Class MAMMALIA: Vertebrate Animals That Nurse Their Young [p.43] Order RODENTIA: Gnawing Animals Family SCIURIDAE: Squirrels, Chipmunks, Prairie Dogs, Ground Squirrels, and Marmots Glaucomys sabrinus canescens Howell Pale Flying Squirrel Glaucomys sabrinus canescens Howell, Proc. Biol. Soc. Washington, vol. 28, p. 111, 1915.       Type locality.--Portage la Prairie, Manitoba.       General characters.--About twice the size of the little southern species.8 Wide membranes connecting the front and hind legs along each side when spread form a monoplane which enables the animal to soar or glide from tree to tree. Tail, wide and flat; fur, very soft and silky, of a delicate cinnamon-brown color over upper parts, creamy white below. Average measurements of adults: Total length, 297 millimeters; tail, 138; hind foot, 37 or 38.       Distribution and habitat.--The pale flying squirrel, a big northern member of the family, comes into eastern North Dakota along [p.44] the timber of the Red River Valley and up some of the streams to the west. Specimens have been examined from Pembina, Grafton, Portland, Grand Forks, and Fargo. These squirrels are common throughout the forest areas of the Pembina Hills and probably occur in the Turtle Mountains, although no definite records have been obtained. At Portland, in 1895, J. A. Loring caught one in a meat-baited trap set under a log in an oak grove. At Grafton, in 1915, Remington Kellogg reported several taken during the preceding winter when the timber was being cleared from some bottomland, but he was unable to obtain any specimens. He found one in the collection of H. V. Williams, which was examined later by Howell (1918) for identification while preparing his revision of the flying squirrels. At Manvel, in the eastern part of Grand Forks County, he reported a family of flying squirrels including a nest and six young, found by a farmer, William Brown, the preceding year; the nest was made of bark fibers and placed in the fork of an elm tree, but when Kellogg examined it it was empty. W. B. Bell told the writer of a family of flying squirrels found by a boy in the woods at Fargo, in 1912.       General habits.--Owing to their strictly nocturnal habits flying squirrels are rarely seen although they are much more common than is supposed. In a wide range over the northern timbered country wood choppers and lumbermen frequently see them leaving the hollow of some falling tree and soaring on widespread membranes to a neighboring trunk, or sometimes, in their confusion, to the ground from which they quickly seek the nearest tree. Usually their nests are within the hollow cavities of tree trunks, sometimes in hollow limbs, knotholes, or the old nest cavities of woodpeckers. Occasionally nests of moss and bark fibers are built among the branches, much like those of the red squirrel. Where the little animals are common it is not difficult to frighten them out of their nests by pounding the hollow trees with an ax. A few smart raps on the base of their trees will usually induce them to peer out of their nests, and continuous pounding will often alarm them into making long flights to neighboring trees. Often one will run to the top of its tree to get a good start and, sailing downward until momentum is gained, go coasting off 50 or 75 feet and, curving gracefully upward to check its speed, strike lightly on the trunk of another tree much lower down than where it started. By running up each tree and soaring downward to the next, the squirrels pass rapidly through the woods until some safe retreat is found.       They are soft, silent, owl-like animals and in the daytime seem sleepy and sluggish. At night their presence is mainly shown by their getting into traps set for fur animals and by their tracks on the snow between trees whose span is too great to be bridged by their soaring flight. Little is known, however, of their real habits except that they make interesting and often mischievous pets, are easily tamed, and become playful and affectionate, but insist on sleeping through the day and carrying on most of their activities at night. They are frequently preyed upon by cats and owls, which occasionally leave their tails uneaten to mark the place of a nocturnal meal.       Food.--A great part of the food of flying squirrels consists of nuts and seeds of trees, shrubs, and vines. At Moorhead, in 1908, Murie [p.45] watched several of them by moonlight feeding on the seeds of ash trees. He says: "They sailed about from tree to tree, stopping occasionally to eat some seeds. Several times I saw one turn a little in its flight and they turned up a little just before landing on a tree trunk." The woods where they occur are usually well supplied with acorns, basswood, boxelder, ash, elm, hackberry, ironwood, birch, and alder seeds and a great variety of berries, grapes, and other seeds, fruits, and buds that remain all winter and are easily obtained, so that generally these animals do not lay up stores of food. They are more omnivorous than most squirrels and will readily take bread, oatmeal, fruit, or meat used for trap bait, and closely related varieties are often caught in marten or weasel traps baited with meat, fur, or feathers.       Economic status.--Though rarely of sufficient abundance to be of economic importance, flying squirrels are, so far as known, practically harmless. Crops and cultivated fruits are rarely if ever disturbed by them and the tree seeds they consume are doubtless well paid for in the scattering and wider planting of those not eaten. As pets for children few animals are more gentle and attractive. Sciurus carolinensis hypophaeus Merriam Minnesota Gray Squirrel; Black Squirrel Sciurus carolinensis hypophaeus Merriam, Science, vol. 7, p. 351, 1880.       Type locality.--Elk River, Minn.       General characters.--Larger and darker colored than the Carolina gray squirrel, with little or no white on the underparts. Color, generally dark gray, often becoming dusky or black. Tail, large and bushy. Average measurements of adult specimens: Total length, 496 millimeters; tail, 220; hind foot, 67. Weight of adult female, 14 ounces (Murie).       Distribution and habitat.--The large Minnesota gray tree squirrels barely come into the southeastern part of North Dakota along some of the timbered stream valleys, although they are abundant throughout the oak region of Minnesota. At Wahpeton, in 1915, an old resident said that he had killed one there 18 years before, but had never seen one since. Later, some squirrels had been brought from Minnesota and placed in a grove on the Dakota side of the river, but they were not protected and all were killed. At Fargo and Moorhead, O. J. Murie remembers them as long ago as 1906, and thinks they have always been there. Since 1910, they have been increasing and in 1919 were common on both sides of the river, and especially in the extensive and beautiful parks just south and north of Fargo, where an abundance of old hollow trees, oak, basswood, elm, and ash, furnish safe homes and choice food. At Valley City, in 1912, Eastgate reported them as introduced in the city parks and slowly increasing. In Minnesota their northern limit seems to be in the vicinity of Crookston, and it would be strange if they did not occasionally extend into the Red River Valley in the neighborhood of Grand Forks. Records, however, are wanting north of Fargo.       General habits.--Besides being good game animals, these large, handsome squirrels are one of the popular attractions of city parks and protected grounds, where they readily become familiar and, with a little care, very tame. Constant hunting keeps them extremely [p.46] shy and secretive in their wild state; but, for rodents, they show a high order of intelligence and quickly learn the protected areas, eagerly responding to friendly advances in the way of food, water, and nest boxes. In their native habitat their food consists very largely of acorns from the numerous species of oaks with which they are associated, but it also includes nuts and seeds of many other plants. For a successful introduction into parks or private grounds they must he supplied with acorns, nuts, or grain.       Their winter homes are usually in the hollow trunks of trees, where in well-protected and warm nests of bark and plant fibers they pass the coldest winter weather in comfort. In summer they build large nests of leaves in the branches of the trees, covering them over to form comfortable, rain-proof houses, with nest cavities in the center, which they enter through half-concealed side doors. In some cases the houses are made large and warm for occupation throughout the winter, but usually a hollow trunk or warm box is preferred for a winter residence.       The interest and delight of children in watching the squirrels, which in parks and private grounds become so tame that they will come to the hand and beg for nuts gives them a value far greater than that of game and fully repays the effort to provide them with comfortable quarters and to plant such trees as will insure their permanent food supply. Sciurus hudsonicus hudsonicus Erxleben Red Squirrel; Chickaree Ahjiduhmo of the Ojibways (Wilson) [Sciurus vulgaris] hudsonicus Erxleben, Syst. Regni Anim., p. 416, 1777.       Type locality.--Hudson Strait.       General characters.--About half the size of the gray squirrel, with full bushy tail and a general reddish or rusty color over the upper parts; a black line along each side in summer borders the white underparts, which in fall is lost in the reddish-gray winter coat. Average measurements: Total length, 340 millimeters; tail, 140; hind foot, 50. Weight, 8½ to 9 ounces (Murie).       Distribution and habitat.--The sprightly little red tree squirrels are generally abundant in the timbered areas along the Red River Valley from Wahpeton to Pembina and along all of the streams which carry lines of timber into the prairie country west of the valley; also in the Pembina Hills and Turtle Mountains as far west as the Mouse River and upper timbered strips of the Sheyenne River near Stump Lake. In 1887 they were common near Fargo, Grand Forks, and Pembina, and in the Turtle Mountains. In 1912, there were said to be a small number in the timber around Lake Elsie, near Hankinson, in the extreme southeastern corner of the State, though they had been mostly killed off there. At Portland, in 1892, J. Alden Loring took a specimen, and reported them as common in the groves along the Goose River. In 1893, A. K. Fisher saw one in the timber along the Sheyenne River near Lisbon. In 1912 Eastgate reported a few along the Sheyenne River 3 miles south of Tolna. At Valley City he reported them as very common all along the river in the timber and occasionally in the larger groves around farm buildings on the prairie close to the river valley, [p.47] and at Lisbon, farther down the river, he said they were common in patches of woods sufficiently large to afford them suitable homes; often two or more pairs were found in a single grove, and from his tent in one of these groves he was able to see three occupied nests at one time. At Fargo they were still common in the timber along the Red and Sheyenne Rivers. Kellogg, in 1915, found them in good numbers at Grand Forks, Grafton, and Pembina; near Towner, in the timber along Mouse River, he reported them fairly common and saw many of their nests in the branches of the trees.       General habits.--In June, 1912, while camping near the fish hatchery in the eastern part of the Turtle Mountains, the writer found red squirrels common throughout the timber, as they apparently are throughout the Turtle Mountains and Pembina Hills. At that season, when the females taken for specimens were still nursing young, they were quiet and keeping out of sight as much as possible. Only once was a subdued barking heard. They live mainly in hollow trees, but a few nests of grass and bark fibers were found in the branches of the trees, and in places the squirrels apparently were occupying burrows and hollow spaces in old stumps and logs. As soon as the young are safely out of the nest and able to care for themselves the squirrels become noisy and for the rest of the year their sprightly chatter and scolding is heard throughout the forest.       Their food consists of acorns, nuts, seeds, mushrooms, and occasionally birds' eggs. Their omnivorous tastes are strikingly different from those of the gray squirrel, and for this reason they have incurred the enmity of those who appreciate the value and beauty of birds as well as of squirrels, and also those who have unprotected corncribs or grain bins to which squirrels may gain access. It is often necessary to reduce the numbers of these cheerful little marauders for the protection of birds and crops, but where they are not doing serious damage they are among the brightest and most attractive forms of wild life either in the forest or in parks and private grounds. In winter, although they spend much of the time within their warm nest hollows, they are active even during the coldest weather, visiting their food caches, to which they gain access by endless tunnels in the deep snow. One of the cheeriest sounds of the forest on a bright winter's day is the long chr-r-r-r-r-r from the feeding branch of one of these squirrels as he cracks a hazelnut or eats an acorn above the glistening field of snow. Eutamias minimus borealis (Allen) Little Northern Chipmunk (Pl. 10) Tamias asiaticus borealis Allen, Monogr., North Amer. Rodentia, p. 793, 1877.       Type locality.--Fort Liard, Mackenzie, Canada.       General characters.--Readily distinguished from the larger gray chipmunks, with which often associated, by the series of fine longitudinal light and dark stripes extending over the back from head to tail, by their slender build, long slender tails and pointed ears, and by the generic character of five molars in each upper tooth row. A specimen from the Turtle Mountains measures in total length, 223 millimeters; tail, 106; hind foot, 33. Weight of adult female, 52.6 grams.       Distribution and habitat.--The little northern chipmunks are abundant throughout the forested and brushy areas of the Turtle [p.48] Mountains and Pembina Hills, and they have been reported in the forest along the Mouse River near Towner (fig. 1). H. V. Williams in 1912, reported them abundant in the Pembina Hills throughout the timbered parts, where they lived in underbrush and around brush piles, old stumps, and fallen trees. They were very tame, but when alarmed always sought protection in their ground burrows rather than in the trees.       General habits.--in all parts of the Turtle Mountains the writer found them more or less common and often very tame and unsuspicious, although nervous and quick to take alarm. Their fine rapid chuck-chuck-chuck notes are usually the first indication of their presence. It is often difficult to locate them by their voices, which are more or less ventriloquial, but by moving cautiously one can usually find a chipmunk perched on the branch of a bush, on a brush heap, or on a stump or log close to its underground home. In a dense thicket careful search is often necessary to locate the voice, but if it does not vanish with a sharp chipper, one may find the little striped gray-coat perched half way up a willow or aspen bush, chirping and waving its tail. To the casual observer its actions may indicate mere curiosity, but its curiosity is far from idle. It involves parental care, mutual protection, watching for enemies, and warning of danger. Although restless sprites, disappearing like a flash and quickly reappearing, at times they will sit quietly for some minutes, calling in a monotonous churp-churp-churp, much like the cry of a robin in distress. If an enemy approaches the note often changes to a more rapid quit-quit-quit suggesting the note of the ruffed grouse when about to take wing. When suddenly frightened they run with a rapid twitter, which at times becomes frantic in their haste to get to cover.       [p.49] in the Turtle Mountains in August, 1887, northern chipmunks were found feeding extensively on the seeds of chokecherries, the shelled kernels of which were stuffed in their cheek pouches, evidently to be stored for winter food. Acorns and various seeds also were found in their pockets. Their feeding grounds show traces of many seeds and berries that have been eaten. They are said to do some mischief in gardens and along the edges of grainfields, but nowhere were they found a serious pest.       In the Pembina Hills in 1919 up to October, they were busily storing seeds and grain. They were often seen with cheek pouches distended, running for their storehouses in underground cavities, where evidently enough food was being laid up to carry them through the winter, for they showed no signs of becoming fat or preparing for hibernation. FIG. 1.--Records of three species of chipmunks in North Dakota: Squares, Gray chipmunk; triangles, little northern chipmunk; circles, pale chipmunk Eutamias minimus pallidus (Allen) Pale Chipmunk (Pl. 10) Sachho of the Arikaras (Gilmore); Hetkadan of the Dakotas (Gilmore); Hinudek of the Mandans (Gilmore); Kokokshi of the Hidatsas (Gilmore). Tamias quadrivitatus var. pallidus Allen, Proc. Boston Soc. Nat. Hist., vol. 16, p. 289, 1874.       Type locality.--Camp Thorne, near Glendive, Mont.       General characters.--Differs from borealis mainly in lighter coloration, which goes with the more open and arid habitat; the brown tones are more yellowish, the gray lighter, and the white markings more extensive. Adult specimens average in total length, 206 millimeters; tail, 91; hind foot, 31. A male of the year taken October 15 at Sanish measured 200, 90, and 30 millimeters, respectively, and weighed 38 grams.       Distribution and habitat.--The sagebrush Badlands country along the Missouri River and westward is the home of the little pale chipmunk. (Fig. 1.) Specimens have been taken at Wade and Parkin on the Cannonball River, Palace Buttes, 6 miles north of Cannon Ball, near Sanish, Williston, Buford, Oakdale, Quinion, Medora, Sentinel Buttes, the former Dakota National Forest, and Marmarth. A little below Williston and near Grinnell and Elbowoods a few are found on the north side of the Missouri River, but generally they are restricted to the country south and west of the river. In 1833, Maximilian (Wied, 1839-1841, Bd. 2, p. 49, 1841) wrote of them: "A few miles below the mouth of the Muddy River, these pretty little four-striped squirrels are in great numbers running along the ground and up the trees with the fruit of rosebushes in their mouths." In 1843, Audubon (1897, p. 27) reported them in the very same place, running over the ground. In 1913, in company with W. B. Bell, the writer crossed the river at this point and was greatly interested to find the chipmunks still there in the brush and timber on both sides of the river. In 1910 H. E. Anthony collected a series at Fort Buford and found them common also on the south side of the river. Near the Sioux Crossing, 6 miles southeast of Buford, he found them abundant along brushy banks and coulées and about ranches where there were woodpiles or old buildings near the banks of ravines on the south side of the river. Some were also found in [p.50] the heavy brush, but apparently they are partial to the more open country. In 1915 Remington Kellogg, on his way down the river from Williston to Bismarck, reported them very common near Grinnell, in Williams County, both in the Badlands and in the brush along Beaver Creek, where several were taken. At Goodall, in McKenzie County, they were very common along creeks, rivers, and in the Badlands. Others were seen along the river on the way down to Elbowoods, where they were most abundant on the west side. Near Expansion in Mercer County, a few were found in the willows, and at Stanton a pair was seen in a buffaloberry bush eating the ripe fruit. They are said to occur at Mandan, and Russell Reid says that he has seen them on the east side of the river at Bismarck. In 1913 Jewett found them in the Badlands and gulches about Medora, near Quinion, and also in the Killdeer Mountains. At Sentinel Butte he collected two specimens among the rocks of the large buttes south of town, and they were found common both along the gulches about the Little Missouri south of Sentinel Butte and on the Dakota National Forest. At Marmarth, in the southwestern corner of the State, they were found common in 1909, over the brushy sides of the Badlands buttes.       General habits.--The little Badlands chipmunks are skilful climbers, but as they generally live in thickets and sagebrush their climbing is mainly through the branches of these dwarf trees and is largely done in search of food or to get high enough above the ground to watch for their enemies. Their real homes are in the ground or in cracks and crevices of cliffs or Badlands banks, to which they dart when alarmed. They are often seen running over the sides of banks and bare walls, from one brush patch to another, or from their dens to the patches of brush and weeds which furnish food and shelter. When alarmed they run with such speed even over the roughest ground that pursuit is useless, and the collector in search of specimens must use much patience and skill to secure them. At other times they are so sure of their safe retreats that they come out boldly to satisfy their curiosity and are easily collected at close range.       Their voice is similar to that of many other species of small chipmunks, but very fine and light. It varies from the slow chip-chip-chip as one sits confidently near a safe retreat, to the much more rapid chipper of alarm as it flies for cover. At times this chipper is heard from the top of a bowlder, the point of a clay bank, or from a branch of bullberry or other bush.       These chipmunks eat a great variety of seeds and berries and a little green vegetation. They seem particularly fond of the bullberries, which in fall load the bushes with masses of scarlet fruit. The seeds of these berries are removed and either eaten on the spot or carried away for winter stores. Serviceberries are also a favorite food. The chipmunks eat the outer pulp of the rose haws as well as the hard seeds within and are fond of the flesh and seeds of the little wild currants and purple gooseberries. Their cheek pouches often contain the seeds of various grasses, sedges, and numerous other plants, which are carried away to be eaten at leisure or stored up for winter use. In the Killdeer Mountains Jewett says that acorns and hazelnuts furnish them with a choice supply of food.       [p.51] Economic status.--In places the Badlands chipmunks become very numerous around the edges of gardens and fields, where they do some mischief to growing crops. Anthony says that at one ranch near Buford they became so troublesome that the owner was forced to shoot them, killing 26 in one afternoon. They are easily trapped or poisoned, however, when it is necessary to thin them out, and by a little care their mischief can be controlled. Tamias striatus griseus Mearns Gray Chipmunk (Pl. 10) Tamias striatus griseus Mearns, Bul. Amer. Mus. Nat. Hist., vol. 3 (1890-91), p. 231, 1891.       Type locality.--Fort Snelling, Minn.       General characters.--Large and heavily built, with broad stripes on the back; readily distinguished from the two species of small chipmunks by larger size, heavier build, more phlegmatic dispositions, more reddish-brown in the colors of the upper parts, and by the generic character of only four molars in each upper tooth row. Average measurements: Total length, 260 millimeters; tail, 95; hind foot, 87. An adult female weighed 3¾ ounces.       Distribution and habitat.--The grayish race of the large rusty-brown chipmunk is common in the timber all along the Red River Valley from Wahpeton to Pembina, and westward along the timbered valleys as far as Lisbon, Kathryn, Portland, Larimore, Grafton, and throughout the Pembina Hills and Turtle Mountains (fig. 1). Apparently they do not reach the timbered area of the Devils Lake region. They are restricted entirely to timbered and brushy areas, where they live in hollow logs, stumps, trees, and underground burrows.       General habits.--The gray chipmunks climb trees readily, but are more often seen running over the ground, logs, stumps, or fences. Their summer nests are usually placed in hollow logs or trees, but their winter homes and food stores are mainly in burrows underground. These burrows are also used throughout the summer as safe retreats and for storing winter food supplies.       The chipmunks are occupied through the spring and early summer with their family cares, and as soon as the half-grown young are out of the nests in June, the search for food, and a little later the storing of a winter's supply of nuts, seeds and grain fill the daylight hours. Soon after frosty nights begin late in September, they enter their winter burrows, where they remain buried under the snow until the following March or April. The four to six young are born about the first of May. During the breeding season they are very quiet and shy, keeping as much as possible out of sight, but later a slow chuck-chuck-chuck is often heard from the woods and thickets, or a shrill chipper of alarm, as the startled animals rush for the nearest cover or up the trunk of some friendly tree.       Their food includes a great variety of nuts, seeds, grains, berries, and some green vegetation, as well as occasional insects, frogs, and lizards. Acorns and hazelnuts are the favorite winter stores and often are deposited in cavities near the nest chambers, a quart or more in a place. Just when these food stores are used is not well known; they may furnish an occasional meal throughout the winter, [p.52] or tide over the drowsy period of entering upon and emerging from hibernation, or carry the chipmunks through the spring, when the ground is still frozen and wet and food scarce, or even through the breeding period. It is improbable that the stores are used up before spring, as hibernation seems to be complete and considerable fat is laid up inside the skins of the animals to carry them through the winter.       Economic status.--In places where they are abundant chipmunks sometimes do serious mischief along the edges of fields, digging up the planted corn in spring and harvesting more than their share of the ripe grain later on. Many of the missing hills of corn along the edge of a brush-bordered field are due to the fact that these little squirrels have carried away the seed just when it was sprouting or earlier. Where their mischief becomes serious it is easily checked by scattering poisoned grain along the fences and under the logs were they run. Citellus tridecemlineatus tridecemlineatus (Mitchill) Striped Ground Squirrel; Thirteen-lined Ground Squirrel; Leopard Squirrel Tashnáheca of the Dakotas; Tshísh-karani of the Arikaras; Naksátshi of the Hidatsas; Mashedónikcha of the Mandans (all, Gilmore). Sciurus tridecem-lineatus Mitchill, Med. Repos., vol. 21 (n. s., vol 6), p. 248, 1821.       Type locality.--Central Minnesota.       General characters.--Short ears, slender body and tail, seven dark-brown and six narrow buff lines on the back, and buffy underparts. The brown stripes are dotted and these distinguish it from chipmunks and all the other striped squirrels. A rather large specimen from Fargo measures in total length, 300 millimeters; tail, 115; hind foot, 39.       Distribution and habitat.--The striped, or thirteen-lined ground squirrel, with its paler western form, covers the whole of North Dakota, and most of the specimens east of the Missouri River are referable to the typical dark form (fig. 2). Belonging to a widely distributed group, covering most of the prairie and Great Plains region of the United States and southern Canada, they are fortunately never so numerous as some of the other species of ground squirrel. They inhabit both the prairie and brushy areas, but usually are not found in heavy timber or on low, wet ground. Open grassy ridges and dry prairies are their favorite habitat, and here their numerous burrows and striped coats afford the best of protection.       General habits.--They are true ground squirrels, spending all but their working hours below the surface in their well-made dens and burrows.9 They are strictly diurnal and are partial to warm weather. Early on bright summer mornings they may be seen running over the prairie in search of food or mates or in playful exercise, but in cold or chilly weather they keep mainly within their burrows, where a supply of food is generally stored. In the tall grass, weeds, or brushy patches they keep out of sight for the most [p.53] part and would rarely be noticed but for their call notes, long bubbling trills, given as signals of alarm or to convey other information among themselves.       Breeding habits.--Breeding activities begin soon after the adults emerge from hibernation in March or early in April, but the actual dates of birth of young are not easily obtained. Females collected in May usually contain embryos showing various degrees of development, but the young do not appear above ground until June or July. They are then nearly half grown and able to run about and take care of themselves under the watchful care of their mothers. When first born the young are very small, naked, and helpless. Doctor Hoy (Kennicott, 1857, pp. 76-77), who observed them in confinement, says that they have no hair on the body before they are 20 days old, and that the eyes do not open till the thirtieth day. The number of young in a litter varies widely, but seems to be usually from 7 to 10. A female taken by Sheldon at Fairmount, on May 9, contained 11 embryos, and there are other records of still larger numbers up to 13 (Lee) and 14 (Seton). The full number of mammae in adult females is 12. Apparently but one litter of young is raised in a season, and even for that the time is short for them to mature and lay up sufficient fat and food to carry them through the six months of hibernation.       Food habits.--Although a great part of their food consists of seeds, grain, and nuts, they are omnivorous in habits and take besides berries and some green vegetation, numerous insects, and the flesh of mice, birds, or any small animals which they can capture or find dead. Acorns and hazelnuts are eagerly gathered and stored for winter food, but over most of their range only the smaller seeds and nutlets are obtained, unless grainfields are within reach. Seeds and grain are stored for future use, but much soft food that will [p.54] not keep is eaten as it is taken. The examination of the contents of large numbers of stomachs shows a considerable portion of grasshoppers, crickets, caterpillars, beetles, ants, cocoons, insect eggs and even traces of flesh, hair or small mammals, and feathers of birds; also green foliage, the white pulp of bulbs and tubers and the fruit of solanum, cactus and strawberries. The contents of the ground squirrel's capacious cheek pouches give a good index to the selection of seeds and grains. The pouches are often distended with wheat, oats, barley, rye, or any of the cultivated grains that are obtainable, but also are found to contain acorns, hazelnuts, seed of sunflower, cactus, bindweed, goosefoot, puccoon, wild peas and beans, and a great variety of grass seeds.       During late summer and fall, all work industriously, laying up their winter stores, quickly filling their cheek pouches and running to the burrows to empty them into the storage cavities near the winter nests. The seeds of native plants are gathered over a considerable area. Sometimes a quart or more is found in a storage chamber, and at the edge of a field where an abundance of grain can be rapidly gathered the winter's stores assume much larger proportions.       Economic status.--In spring the planted seed is dug up and eaten or stored from the time it is sown until long after it has sprouted. Then the green stalks are eaten during the early summer, and as soon as the grain is headed out great numbers of the heads are cut off for kernels, from the very beginning of their formation. Thus, before harvest time the edges of the grainfields have become ragged and thin for a considerable distance into the field. Although depredations of these ground squirrels do not compare with those of the more abundant Flickertails, their wide distribution over North Dakota and many other States renders them one of the most serious of rodent pests.       But for their natural enemies, which are legion, it would be impossible to raise crops within their territory. They are constantly preyed upon by many species of hawks, and some owls, and by foxes, weasels, skunks, and badgers, so that in spite of their rapid increase their numbers are usually kept somewhat within bounds. However, it is necessary over much of their range to supplement the work of their natural enemies by the systematic use of poison. FIG. 2.--Distribution of the thirteen-lined ground squirrel (1), and its pale western form (2), in North Dakota Citellus tridecemlineatus pallidus (Allen) Pale Striped Ground Squirrel; Pale Thirteen-lined Ground Squirrel Miniwakao of the Cheyennes [Spermophilus tridecemlineatus] var. pallidus Allen, Monogr. North Amer. Rodentia, p. 873, 1877.       Type locality.--Plains of Yellowstone River, Mont.       General characters.--A pale western form of the thirteen-lined ground squirrel, slightly smaller, and with paler tones of buff and lighter brown stripes. Average specimens from the type region measure in total length, approximately 255 millimeters; tail, 82; hind foot, 84.       Distribution and habitat.--The striped ground squirrels become gradually paler across the middle part of the State, but not until the semiarid Badlands country is reached west of the Missouri [55p.] do the pale forms become clearly recognizable. In the part of the State west and south of the Missouri, they are the only ground squirrels, and here with the prairie dogs they occupy the short-grass plains country in considerable numbers. While sometimes seen in the open, where there is not sufficient grass to conceal them, they are more often found in the better cover of grass and weeds and low bushes. In this region they were originally one of the interesting and harmless forms of native life, but since grain farms have spread over it they have become one of the serious problems with which the farmer has to contend.       General habits.--In habits these squirrels do not differ from their darker relatives to the eastward, except as a change of environment gives them other kinds of food and local conditions which they seem always ready to meet. In many places some protection is sought for their burrows, such as grassy spots or weedy ground. Sometimes a piece of paper or cloth is drawn over the entrance to the burrow, apparently for concealment or protection.       At Parkin, on June 28, 1916, a burrow was found where fresh earth had been lately thrown out and the entrance was securely packed with sand from the inside. As the entrance to this burrow was opened a half-grown young of the species poked its head out of another entrance near by. In the tunnel, about 8 inches below the surface of the ground, was found a large, soft nest in a roomy chamber, with two doors opening out on opposite sides. The nest was made of dry grass, bark fibers, and bits of paper from the railroad track. It was soft and well matted together like a bird's nest, but not covered over. The young had escaped in the branching burrows. Evidently this was their home nest, from which they had not yet begun to make excursions to the world above. The closing of their doors from within was evidently in this case to protect the young from outside enemies.       Economic status.--In many places it has been found necessary to poison these squirrels for the protection of grainfields and garden crops; the methods given for the Richardson ground squirrel, or flickertail, will be found to apply equally well to this species. Citellus franklinii (Sabine) Gray Ground Squirrel; Franklin Ground Squirrel Arctomys franklinii Sabine, Trans. Linn. Soc. London, vol. 13, p. 587, 1822.       Type locality.--Carlton House, Saskatchewan, Canada.       General characters.--Largest of the ground squirrels of this region; sometimes mistaken for the gray tree squirrel, which it approaches in size and slightly resembles, but from which it differs in slender form, very short ears, and much smaller and less bushy tail. Color, dark gray with a brownish wash and a mottled effect in fine, wavy cross lines or scallops over the back. Adults measure in total length 388 millimeters; tail, 136; hind foot, 55.       Distribution and habitat.--Extending over a wide range in the central United States and Canada, from Oklahoma and Illinois to the Athabaska River, the large gray ground squirrels cover approximately the eastern half of North Dakota (fig. 3). Their greatest abundance within the State lies within the Red River Valley and westward to the Dakota River Valley, Devils Lake, and the Mouse River. There is an indefinite record for Burleigh County near Bismarck, [p.56] and another for Turtle Lake in McLean County, but the most westward authentic record is from Kenmare, in the valley of the Riviere des Lacs, where W. B. Bell collected a specimen in 1913. They are particularly animals of open timber and brush land and do not occupy wide stretches of prairie unless there is ample cover for concealment. FIG. 3.--Records of the Franklin ground squirrel in North Dakota       General habits.--Although occasionally seen up among the branches of low trees, the Franklin squirrels are strictly ground squirrels, living in burrows generally concealed in brush or weed patches, from which well-worn trails or runways radiate to other burrows or feeding grounds. They are shy and secretive, keeping much under cover of protecting vegetation, as they are too large and dark colored to be inconspicuous the open. When frightened they rush for their burrows, usually uttering a trill of alarm and warning to other members of the family. Their voice is much like that of the thirteen-lined ground squirrel but is as much heavier as they are larger. It is often heard in a long bubbling trill from a weed patch and is almost birdlike in musical quality.       In the timber and brush patches along the Red River Valley, about Stump Lake, Devils Lake, the Sweetwater Lakes, and in the Turtle Mountains, the squirrels are especially numerous and in such situations they are generally the most abundant of the three species of ground squirrel occupying the general region. Throughout the Turtle Mountains they were found along the edges of meadows, fields, and clearings along roadsides, and in all the open places where woods and small brush served for cover. They gathered around camps or dwellings where there were no dogs or guns and even came into the writer's cabin and helped themselves from the grub box. They persisted in getting into traps set for others long after enough of them had been secured for specimens and most of the trails and runways attributed to other animals proved to belong to them. [p.57] Their burrows were generally in groups of three or four, or more, not far apart and evidently connected below ground. They were in all sorts of situations, but a sloping bank, brush heap, old log, or stone pile usually provided the protection sought for their dens. A considerable quantity of earth is usually thrown out in front of one of the burrows but others open out with less conspicuous markings. Many old dens and burrows are located through the brush and woods and one seems always to be convenient when danger approaches. Often the animals will stop at the entrances of their burrows and straighten up in the picket-pin attitude, to make sure whether an enemy is pursuing. If approached too closely, they quickly dive into their burrows with a flirt of the tail and a parting chatter, but if all is quiet they soon reappear cautiously to reconnoiter.       Franklin squirrels are easily tamed and make interesting, though rather mischievous, pets. H. V. Williams, at Grafton, had a tame one for which he made a den by burying a box underground. The squirrel carried about a half bushel of grain into this box, and in fall hibernated as usual. When examined in January it was unconscious, but before its awakening time in spring water ran into the box and it was drowned. While collecting specimens at Fish Lake in the Turtle Mountains, Williams fed one around his tent until it became so tame as to take food from his hand and come to the tent regularly at meal times. It finally became so bold that it would enter the tent and search through the baggage for food. After breaking and carrying off a lot of birds' eggs that had been collected for specimens it had to be killed to prevent further trouble.       Hibernation.--With the first freezing weather in fall, usually in September, Franklin squirrels go to their nests deep underground and usually do not reappear until the following April. Before entering upon their hibernation they become very fat and depend upon this concentrated form of nutriment to carry them through the winter rather than upon the ample stores of food laid up in convenient chambers near their nests. Just when these stores are eaten is not well known, but probably before the squirrels have become entirely inactive in fall and again before the outside food supply is available in spring.       Breeding habits.--Their half dozen young are usually born in May or June and by the last of July are half-grown squirrels, out of the burrows, and hunting for their food.       Food habits.--Living largely upon nuts, seeds, and grain, these squirrels show an appetite for a wide range of food. The examination of a large number of stomachs and cheek pouches shows their food to consist not only of a great variety of grains and seeds, but also of berries, green vegetation, roots and bulbs, beetles, caterpillars, grasshoppers, crickets, ants, and eggs and pupae of insects. They also eat young birds, birds' eggs, and young mice, and are said to kill young chickens. When caught in traps or found dead they are even eaten by their own kind. They feed upon grain from the time the seed is planted until the last bundle is removed from the fields. Unlike the smaller ground squirrels, they do not cut the standing grain, but pull down the heads and in this way destroy the grain even more rapidly. In their capacious cheek pouches seeds of [p.58] grain are rapidly carried to their winter storehouses. Where a large number of the squirrels gather along the edge of a field they will often harvest considerable of the grain after having fed upon it during every stage of its growth through the summer.       Economic status.--To a great extent the Franklin squirrels occupy the limited areas where the other two ground squirrels of the State, the thirteen-lined and the Richardson, are absent or less numerous. In extensive areas, therefore, they are the dominant species and levy their toll of destruction on the grainfields and gardens that otherwise would be comparatively safe. In some places, however, the three species occupy the same ground and in combined numbers cause enormous losses of crops. Although larger and according to their numbers possibly more destructive to grain than the Richardson squirrels, the Franklin ground squirrels are apparently less numerous in most of their habitat. They are easily poisoned and their abundance may be controlled at comparatively little expense, using the same methods as recommended for the Richardson, or flickertail. Citellus richardsonii (Sabine) Richardson Ground Squirrel; Flickertail Honkóta of the Arikaras; Pinsa of the Dakotas; Shopka-sop of the Mandans; Tsipá sopa of the Hidatsas (all, Gilmore). Arctomys richardsonii Sabine, Trans. Linn. Soc. London, vol. 13, p. 589, 1882.       Type locality.--Carlton House, Saskatchewan, Canada.       General characters.--A plump little ground squirrel much resembling the prairie dog, but about half the size. Color, rich buffy yellow, darkened over the back with obscure mottling and wavy scallops. Ears, minute; tail, short. Measurements of average adult: Total length, 237 millimeters; tail, 73; hind foot, 45. Ebner gives the usual weight In fall as 16 to 17½ ounces and in spring as 11 to 13 ounces.       Distribution and habitat.--From a wide range over southern Saskatchewan, Alberta, and Montana, Richardson ground squirrels, or flickertails, cover practically all of North Dakota east and north of the Missouri River (fig. 4). They are absent from most of the immediate valley of the Red River and the wooded bottoms and timbered areas generally being most abundant over the high open prairie of the central part of the State. For some unknown reason they seem to stop at the Missouri River where the prairie dogs begin, although the ranges of the two species overlap slightly in Montana, where no enmity between them is noticeable. The more humid and fertile part of the country was occupied by them long before the great wheatfields spread over their range to supply a new and choice food. Of the three species of ground squirrel in the State, these are by far the most numerous and most destructive. FIG. 4.--Records of the Richardson ground squirrel in North Dakota       General habits.--Originally the flickertails had a continuous distribution over the prairie in great numbers. On some favorite slopes they were so numerous as to suggest a colonial tendency, but apparently this only showed a preference for certain kinds of ground yielding an abundant food supply.       In 1887, when much of the prairie was still unbroken, they were living in their primitive manner on such food as the prairie afforded and doing practically no harm except as grainfields and crops encroached [p.59] upon their original range. Their greatest numbers often appeared to be in the areas of the shortest grass and lowest vegetation, possibly because the grasshoppers and other insect life on which they fed to some extent were most easily obtained there. In places the prairie seemed alive with them and they could be seen scampering about together or standing up like picket-pins, while their shrill whistle was heard on all sides. With each call-note their short little tails are flipped up and down, a farewell twinkle being given as they disappear down the burrow, hence the popular name of "flickertail." In 1887 they were often seen also in the main streets of Devils Lake and Bottineau, which were then in their early stages of construction, and in 1916, it was most surprising to find them still occupying vacant lots on the edge of the city of Devils Lake. It was a striking illustration of their tenacity in holding to their original habitat through years of vigorous but sporadic efforts to destroy them.       As soon as the grainfields spread over their range they quickly gathered along the edges to feast on this wonderful new and abundant food. They did not long confine themselves to the edges of the field, however, but went into the middle of large cultivated areas and made their burrows in the plowed ground or in the growing grain.       No reliable estimate of their numbers can be obtained, but a general idea of their abundance may be gained from the statements of Elmer T. Judd, of Cando, in a letter of August 1, 18,90, in which he, says:       An old gentleman here killed 1,500 'gophers' by actual count, before the first of June. From the first of June to the middle of July, he and a cotton broker from St. Louis, who spends the summer here on his farm, calculated that they killed over 2,500 more. One forenoon they killed 135, as shown by the tails they had captured.       [p.60] These 4,000 animals were killed on and around the outer edges of one section of land.       Breeding habits.--The number of young to a litter is given by Ebner as 6 to 11, with an average of 7 or 8, born in the underground nests mainly in May. By the first of June the young are out of the burrows and find part of their own food while still under the anxious care of their mothers. Small young are occasionally seen much later than the first of June, and apparently the breeding season extends over a considerable period. It has been supposed that flickertails raise two or more litters in a season, but this seems improbable on account of the brief period between their emerging from hibernation in the latter part of March or early April, and entering hibernation in the latter part of August or early in September. This is scant time for even the earliest young to get anywhere near their full growth and lay in sufficient fat to carry them through the winter. By the first of September there are always many individuals that are still small and these are the last to hibernate, presumably because they have not laid up sufficient fat. Even in spring many of those that are seen before the young are born are not nearly full grown and apparently these late young of the previous year are late in breeding. The principal mating season is early in the spring soon after hibernation but sometimes it is as late as the latter part of June. On September 1, 1914, at Bismarck, a few were seen but these were the young of the year, the adults having already gone into their winter dens. At the same time, Silver, who had been studying them at Garrison, for the previous week reported only young of the year caught. At Van Hook on October 16, 1919, the writer saw one out on a warm, sunshiny day after a cold wave, but none had been seen before for some time.       Food habits.--During the summer much green vegetation is eaten by the flickertails--largely the leaves and stems of grain, grass, and a great variety of succulent plants--and apparently it would be possible for these rodents, like the prairie dogs, to subsist entirely upon such vegetation were no grain and seeds available. Late in summer and in fall, when the seeds of the prairie plants and grasses begin to ripen, they constitute the principal food of the squirrels. An important part of the summer food consists also of such insects as grasshoppers, crickets, and caterpillars, though these vary greatly with season and locality. At Crosby, in July, 1913, they were found feeding extensively on the little juicy striped-backed armyworm caterpillars, which swarmed over the roads and fields. Some of the squirrels examined had their stomachs half full and others entirely filled with the caterpillars. Where grasshoppers are abundant they are often fed upon extensively, but wherever grain can be obtained it seems to be the favorite food. One flickertail, shot as it ran out from under a shock of grain, had 269 kernels of oats in its cheek pouches. One recorded by Seton had 162 grains of oats in its pouches and another 240 grains of wheat and nearly a thousand grains of wild buckwheat. Their cheek pouches are so capacious that when well filled they often make the head appear more than double its natural size. The stores gathered are rapidly carried home to be deposited in the burrows and large quantities of food are thus provided for future use. No [p.61] stores of grain have been found in the hibernating dens, however, and more study is needed to show when it is used.       Destruction of crops.--The annual loss in grain crops in North Dakota occasioned by these ground squirrels has been estimated at $6,000,000 to $9,000,000 in addition to the annual expenditure of at least $100,000 of public and private funds to combat their depredations. Their tendency is to multiply rapidly in a well-settled and cultivated part of the country because many of their natural enemies are destroyed or kept at a distance, and the food supply is most abundant. As soon as they emerge from hibernation early in spring they begin digging up the seed and eating the young grain that has been sown in the fall and as soon as the spring sowing starts they dig up the new seed and eat or carry it away. When the grain sprouts they dig both sprout and kernel, and after the kernels are entirely exhausted they feast on the young growing grain until it is headed out, when they begin on the young heads, cutting down the stalks and eating the young seed through all its growing stages. As soon as the grain is ripe they carry it away as rapidly as possible to their storehouses, and this is continued until the last bundle is removed from the fields. Four thousand of these squirrels on or around the edges of a section of land would remove a considerable portion of the crop, and it is not surprising that they are considered the greatest pest of the region. They seem to have no preference between wheat, rye, barley, oats, or flax, but take whatever is nearest their dens.       Natural enemies.--The natural enemies of these ground squirrels are numerous, and but for them the abundance of the animals would be many times greater. Badgers are constantly digging them out and feasting upon them, from early spring until long after they have hibernated or until the ground becomes well frozen and the badgers themselves go into winter quarters. The long-tailed weasels enter their burrows and kill and feed upon them without the least trouble or hindrance and apparently destroy great numbers besides those merely killed for food. At the first appearance of one of these weasels, the squirrels give frantic alarm calls that set the whole prairie community in a panic. They rush to their burrows, but the weasel follows and helps itself to as many as it cares to kill for food or pleasure. This goes on as long as the burrows are open and probably even during the winter, when the weasels can gain access to the dens through the snow, as they are active all winter and sleeping squirrels fill their needs as well as any others. Skunks probably dig out a few, and foxes, coyotes, and bobcats help also to reduce their numbers.       Hawks and some owls prey upon them to a greater or less extent. The ferruginous rough-legged hawk apparently feeds upon them almost exclusively where they occur in its neighborhood and brings them in to feed its hungry broods. The Swainson, marsh, red-tailed and red-shouldered hawks feed on them extensively, and even the bird-catching sharp-shinned and Cooper hawks may occasionally take one. The little sparrow hawks, which feed mainly upon grass hoppers, probably destroy some of the young ground squirrels, and it is likely that both the short-eared and long-eared owls capture many of them during early evenings or on cloudy days. Gopher [p.62] snakes feed upon them to considerable extent, but few data are available in regard to some of the most important species of snakes. The protection of such of their natural enemies as are not otherwise harmful in habits is one of the most important measures for the control of these ground squirrels.       Methods of destruction.--Most efficient methods of controlling these ground squirrels have been carefully worked out by members of the Biological Survey and the North Dakota Agricultural College and Experiment Station. In campaigns against these squirrels, the most economical preparation of poison that has been found to be effective is grain lightly coated with strychnine and starch in the proportions of 1 ounce of strychnine alkaloid to 1 tablespoonful of gloss starch made into a paste with 1 pint of boiling water and stirred into 20 quarts of oats. A teaspoonful of this coated grain placed near each occupied burrow disposes of a large percentage of the squirrels at the first application and the few that remain can be practically cleaned up at the second application. Well-organized and coordinated work over a large area is necessary for satisfactory results, as no matter how thoroughly the squirrels are cleaned out from one or a half dozen farms they will quickly reinfest the whole area from those remaining. This preparation of poisoned grain is equally successful with the other species of ground squirrels and chipmunks where it is necessary to reduce their numbers or clean them out of a section of country.       Ground squirrels as pets.--On a street car from Devils Lake to the Chautauqua Grounds one day the writer saw a boy who had one of these squirrels, which he had caught with a snare earlier in the day. It was about half grown and had become so gentle that he was playing with it and handling it freely, letting it climb his coat sleeve and carrying it in his pocket or in his cap on his head. It made no attempt either to escape or to bite, but snuggled up to him in a way that suggested the possibility of using these squirrels as pets for children, a vital need that is not well met by any of our domestic animals. Cleaner, neater little pets could not be found. Although quiet in disposition, they have sufficient vivacity to be very attractive. If taken young and well tamed these native squirrels would certainly be far more attractive, interesting, and intelligent than white mice, rats, or guinea pigs, which seem to be the only small mammals available for this important phase of child development. The supply would be endless and easily obtained, and by using only one sex in one part of the country any danger from recolonization would be avoided. Cynomys ludovicianus ludovicianus (Ord) Black-tailed Prairie Dog Pinspinsa of the Dakotas; Achks of the Arikaras; Shopka of the Mandans; Sinhpa or Tsipá of the Hidatsas (all, Gilmore). Arctomys ludoviciana Ord, Guthrie's Geogr., 2d Amer. ed., vol. 2, pp. 292, 302, 1815. (Reprint by S. N. Rhoads, 1894.)       Type locality.--Upper Missouri River, where discovered by Lewis and Clark.       General characters.--Prairie dogs might be described as big, husky ground squirrels or little, plump woodchucks, to both of which they are related and [p.63] between which they range in size. Although belonging to the squirrel family, they are compactly built for digging and for life on and under the surface of the ground. The ears are minute, the tail short, and the legs short and muscular. The color generally matches well the fresh yellow earth of their burrows, being a yellowish or pinkish cinnamon above and buffy below; the tip of the tail is blackish, and coarse black hairs are scattered over the upper parts; the fur is soft and silky in winter, coarse and harsh in summer. Average measurements: Total length, 388 millimeters; tail, 86; hind foot, 62.10 Weight, 2 to 3 pounds.       Distribution and habitat.--From a wide range over the Great Plains from western Texas to northern Montana, these prairie dogs extend over that part of North Dakota west of the Missouri River (fig. 5). In this latitude they are all west of the Missouri River, but farther south they occur on both sides. Fortunately they are colonial in habits and have a scattered distribution, so that the country is not fully occupied by them, but the colonies, or "dog towns," have been numerous over the part of the State which they occupy. In 1910, Anthony reported a few prairie dogs on the south side of the river not far from Buford, and many 20 miles south of there. In 1909, prairie-dog towns were reliably reported near Mannhaven, just west of the Missouri River, and on the Little Missouri near Marmarth in the southwest corner of the State. In 1913 there was a considerable dog town east of Sentinel Butte. In 1913, Jewett reported a large colony on the flats about a mile west of Fort Clark, where the prairie dogs were doing considerable damage to crops, another colony on a piece of level prairie about 3 miles east of Oakdale, and many others along the Little Missouri River from Quinion to Medora, with exceptionally large colonies at the mouth of Ash Creek and near the head of Magpie Creek. Most of the dog towns he found around Sentinel Butte had been destroyed, but a small colony still existed about 10 [p.64] miles east of there. A considerable dog town was located a couple of miles east of Medora and another along the Northern Pacific Railroad between Hebron and Glen Ullin. Kellogg, in 1915, found near Goodall an uninhabited dog town that had covered about 400 acres. A small colony on the west side of the river opposite Elbowoods was said to be decreasing in population. About a mile north of Mannhaven a colony was found covering about 100 acres. At Stanton there had formerly been a large colony but it had been destroyed by poison. In 1915, Sheldon reported a small prairie-dog town on Deep Creek near the former Dakota National Forest, and other colonies scattered over that general region. At a point about 4 miles northwest of Cannon Ball he located a town containing about 2,000 prairie dogs and covering an area of approximately 160 acres. Another colony was located near old Fort Rice, covering about 40 acres and containing about 500 animals; still another about 9 miles south of Cannon Ball of approximately 90 acres and about 500 animals. He was told that the Indians had kept them down by shooting them for food. Near Wade, in 1913, Doctor Bell reported them as occurring in scattered colonies. FIG. 5.--Distribution of prairie-dog towns in North Dakota       In 1915, U. S. Ebner, in charge of field operations in the rodent control work of the Biological Survey in cooperation with the North Dakota Agricultural College and Experiment Station, investigated the prairie-dog situation over a part of the range west of the Missouri River. He reported small prairie-dog towns covering 25 to 250 acres scattered along the Little Missouri River in Billings County, larger colonies of 60 to 640 acres in the northern part of Dunn County, a number of towns of 20 to 160 acres along Big Beaver Creek in the northern part of Golden Valley County, other towns of 25 to 500 acres in the eastern part of McKenzie County, and some large towns running as high as 600 acres on the Berthold Indian Reservation. In most of these prairie-dog towns he estimated 20 to 40 burrows to the acre.       Although these records show only the colonies that have been located, they indicate a very general distribution of prairie dogs over this part of the State, and a careful survey would doubtless show a surprising number of inhabited prairie-dog towns in a region that is rapidly filling up with grainfields.       As a general thing the colonies are located on the open level prairie and often on the best of the grain land. In the Badlands they are usually on the flat and level spaces where the best grass grows, always away from the brushy and barren areas.       General habits.--Prairie dogs are highly social in disposition, almost invariably living in colonies. On rare occasions a new location is chosen where family or a few prairie dogs have started a colony, but generally there is evidence of their long residence. The old burrows and mounds remain for many years and the sites of ancient prairie-dog towns are marked by little swells of grassy turf scattered over the prairie.       A well-populated prairie-dog town on a bright summer morning is as animated as any busy village could well be. At the first appearance of the sun the animals come out of their burrows and begin their breakfasts of grass and roots, most of them busily digging up grass and little plants for food, nibbling off the grass blades and [p.65] plant leaves like rabbits, or sitting up holding them in their hands like squirrels. There are always, however, a few on sentinel duty, usually sitting straight up on the highest mounds, or stretching up occasionally to full height from the grass where they are feeding. Some are always scampering from one point to another, and when the young are out there is much playing and scuffling among them. A populous town of prairie dogs, all busy and many of them calling back and forth, with a few on sentinel duty, barking in steady little yap-yap-yap-yaps at some real or imaginary enemy, makes an interesting picture. If an enemy really approaches, the barking becomes frantic and is taken up by other members along the line, and there is a general scamper for the nearest burrows. If one walks toward them to within rifle range the panic increases and the nearest animals rapidly disappear down the burrows with a farewell twinkle of their tails. The barking passes along farther and farther through the town, usually beyond where the enemy can be seen, every prairie dog taking notice and most of the them joining in the alarm. Occasionally one of the guards will stretch up to its utmost height and throwing its head back utter a long Chu-r-r-r-r-r-r-r-r-r-r, as if a dozen barks were crowded into one. This seems to be their only note besides the regular yap-yap, and a chuckling, scolding Chu-r-r-r-r-r, after entering their burrows, as if they were grumbling at having been disturbed.       The burrows are deep and go down at steep angles, sometimes almost straight down, for 2 or 3 feet and then slope off gradually. A pebble dropped into one can be heard rolling and bounding down, often for 5 or 6 feet, and a prairie dog with a string tied to its hind foot will sometimes take down 12 or 15 feet of string before reaching the end of the tunnel. The burrows are simple and almost never lead out to a second opening.       The nest, instead of being at the lowest point, is usually in a chamber well protected from any rain water that may run down the burrow. As a further protection the earth thrown out is carefully placed around the entrance to form a craterlike rim that serves the double purpose of a watch tower and a dike to prevent the entrance of water from heavy rains.       Originally the mound is built of the earth brought out of the burrow, but later fresh earth is scraped up from outside and brought back and added to the sides, and when the ground is moist after a rain the mound is carefully formed and patted and pushed with the end of the nose until externally it has the most approved slopes and internally the correct funnel form. A well-kept mound shows numerous dents and dimples where pushed and poked with the pudgy noses of the prairie dogs. Many old burrows with neglected and broken mounds are used, but the main nest burrows are always kept in good condition. Nest material of dried grass and soft plant fibers is carried into the burrows and the old material is occasionally brought out and scattered about the entrance. The cheek pouches of the prairie dogs are small and little used, and apparently no food is stored.       Breeding.--The 4 to 6 or 8 young are born early in May, but usually do not appear out of the burrows until the first or middle of June. They are then seen in family groups around the entrance to [p.66] their homes and always under their mother's watchful eye. At a signal from her they quickly rush to the burrow and disappear. As their experience increases they are left more to their own discretion, but even when half grown if danger appears the mother insists on their all getting down the burrow before she will enter. Small young are often seen later in the year, but in the northern part of their range it is doubtful if more than one litter is raised in a season, the late young probably being the first litter of females of last year's brood.       Hibernation.--In fall the adults become very fat and the young moderately so. They are always ready to hibernate in case of very cold or stormy weather or deep snow, but do not enter their dens to remain unless cold weather comes. In mild seasons they are sometimes active until midwinter and may be seen foraging on warm days when there is no snow. In severe winters, however, they disappear for a long period and evidently pass completely into the state of hibernation. They are out with the first warm days of spring and in March, when a few sagebrush tops were the only visible vegetation, the writer has seen them sitting on top of 2 feet of snow through which they had burrowed to the surface. As soon as the snow is off in spring they find plenty of food in the dry grasses and roots, and their store of fat helps to carry them through the mating season.       Food habits.--The food of the prairie dogs consists principally of grass, including seeds, leaves, stems, and roots, but it includes also everything that grows over the surface of the ground to a considerable distance around their burrows. The short blades of grasses are not only eaten off to the ground, but the roots also are dug up and the tender bottoms of many species are eagerly eaten. Other little plants are eaten to the ground and those with edible roots or bulbs are dug up and exterminated. Often tall plants, grasses, and weeds that have sprung up in the prairie-dog town are cut down, if not for food, to keep the ground clear and the view unobstructed. An old and well-populated prairie-dog town is often so completely cleared of vegetation that parts of it have to be abandoned, the animals moving on toward the best grass on the margins. In this way parts of the prairie are progressively denuded of vegetation.       The stomachs of prairie dogs are relatively large, as in all grazing animals, and at any time of the day except early morning they are found well filled with finely masticated vegetation, usually showing a good combination of green and white pulp from the foliage, stems, and roots of plants, often with streaks of color from various kinds of flowers and seeds. Many ripening seeds are included in their food, and fields of grain tempt them to extend their colonies into this unusual food supply. When the dog towns are plowed up and seeded to grain the occupants cling to the old burrows with great tenacity, opening them up and if left undisturbed living in the midst of wide grainfields.       Depredations.--An area occupied by a colony of prairie dogs may usually be considered stocked to its carrying capacity and of little or no value for grazing or agricultural purposes. It may also be considered that the area thus occupied is just so much withheld from [p.67] other use, and it is only a matter of determining the area of land given over to these animals to know the extent of the loss in grazing. If a well-populated prairie-dog town is plowed and seeded, prairie dogs will be the ones to harvest the grain unless they are first destroyed.       Destruction of prairie dogs.--Fortunately prairie dogs are easily poisoned by the use of oats or other grains coated with strychnine, as described for the Richardson ground squirrel, and a farm suffering severe losses may be reclaimed at comparatively small expense. Full directions for preparing and using the poisons will be furnished by the Biological Survey on request. Marmota monax rufescens Howell Rufescent Woodchuck; Groundhog Marmota monax rufescens Howell, Proc. Biol. Soc. Washington, vol. 27, p. 13, 1914.       Type locality.--Elk River, Minn.       General characters.-Heavy-bodied animals, with short ears, short legs, and short, bushy tails. Similar in general appearance to the southern and eastern woodchucks, but more reddish brown above and below. Upper parts dark brownish gray, sides and underparts strongly washed with reddish or rusty brown; feet blackish; tail black or dark brown, longhaired and bushy. Average measurements: Total length, 548 millimeters; tail, 143; hind foot, 83.11 Weight, about 8 to 12 pounds, but individuals have been recorded as heavy as 13½ and 18 pounds. (Anon., 1900; Fellows, 1881.)       Distribution and habitat.--From the Transition Zone of the eastern United States woodchucks extend across Minnesota and into southeastern North Dakota as far as Devils Lake (fig. 6). In revising the group Howell examined specimens from Fargo, Grafton, and Leonard, in North Dakota; and at the biological laboratory in 1913 there were skins collected near Stump Lake and Devils [p.68] Lake. At Wahpeton woodchucks are reported common along the banks of the timbered river bottoms. At Fargo and Grafton they are occasionally found. In 1915, Kellogg collected a half-grown young near Larimore and obtained a specimen at Grafton. While at Manvel, Grand Forks County, he saw their burrows and one young that had been captured. In 1919, Williams reported then becoming more numerous each year at Grafton. Eastgate says they are occasionally found in the forest near the biological laboratory at Devils Lake, but that they are by no means common. Apparently they fill the forested belts along the rivers, extending west from the Red River Valley and thus reaching the Devils Lake and Stump Lake forested tracts. Although mainly restricted to forested and brushy locations, where no timber is available they will live in the open. Steep banks and sidehills are favorite situations, but in many cases the burrows are found on level ground or under stumps, trees, or stones. Woodchucks are not fastidious as to habitat, the one requisite for their existence seeming to be an ample supply of green food during the summer season. FIG. 6.--Localities where woodchucks are known in North Dakota       General habits.--These largest and least squirrel-like of the squirrel family have generally the burrowing habits of the ground squirrels and prairie dogs. They are mainly burrowing and grazing animals, occupying the region of rich plant growth rather than the short-grass prairie, and depending to a great extent on cover and concealment for protection. They are not colonial in habits, except as mother and young remain together during the season, but if undisturbed they often multiply so rapidly as to be seriously destructive to crops and forage.       Their burrows are extensive, and instead of being one simple tunnel, usually open out in two or more directions from the central den. Near Larimore Kellogg dug out a den where an old female and her half-grown young were living. There were four entrances and three nests in different chambers. The nests were made of dry grass and leaves and one contained some fresh-cut plants, including nettles. The branches of the den were respectively 6, 7, and 9 feet long, but apparently there were other branches not discovered, as the old woodchuck and her young had been seen to enter the burrow, but could not be found. When first seen, one of the young was up in a basswood tree and when alarmed ran down into the burrow. These woodchucks are good climbers and in places where there are no fences or rocks to serve as watch towers, they are often found up in trees where a good view can be had. They also take refuge in trees to escape from dogs and other enemies. A family of seven young is reported from Manvel, by Kellogg, and this seems to be about the average number for the species.       Food habits.--The food of woodchucks consists largely of green vegetation, with which their large stomachs fire usually filled. They are particularly fond of clover, alfalfa, or any of the native leguminous plants, but will eat grass and growing grain and vegetables with great relish. In fall, flowers, seeds, and grain furnish a richer food from which more rapidly to accumulate their winter fat. Apparently they do not lay up stores of food, but depend on finding an ample supply until time to hibernate, and in spring live on their store of fat until green vegetation is available. They usually come [p.69] out in spring while the ground is still covered with melting snow. Doctor Bell took a specimen at Fargo on April 29, 1906.       Economic status.--The fondness of woodchucks for almost every kind of garden or field crop renders them serious pests wherever they are numerous. Here on the border of their range they may never become troublesome, but they should be watched and their numbers kept down wherever an undue increase is noticeable.       It is unfortunate that the habits of so many of our native animals conflict with the interests of man, as their presence would otherwise add much to the interest of life. A few woodchucks in the meadow and along the fences, where their loud, shrill whistle is occasionally heard and where they are seen sitting up in the grass or on the fence watching for danger, or with flopping tails scampering to their burrows, would add a touch of life and interest to any landscape. Their depredations, however, are too serious to be taken lightly, and it is often necessary to destroy them. Usually they may be shot or trapped, or killed with carbon disulphide placed in their burrows, but they are not easily poisoned, as there is usually an ample supply of their favorite food within reach.       Woodchucks as food.--Woodchucks have some value as food animals; their meat is like that of squirrels, but coarser. Many persons are fond of them, and in the markets they sometimes bring as much as a dollar each. There could be no cleaner or more exemplary animal in food habits and their underground dens are as clean and fresh as the abode of any burrowing animal. When necessary to destroy them their use as food should be encouraged. Marmota monax canadensis (Erxleben) Canada Woodchuck; Groundhog [Glis] canadensis Erxleben, Syst. Regni Anim., p. 363, 1777.       Type locality.--Quebec, Quebec, Canada.       General characters.--In size somewhat smaller than rufescens. Color, strongly rufescent. Average measurements: Total length, 513 millimeters; tail, 108; hind foot, 76.       Distribution and habitat.--From a range extending across Canada from Nova Scotia on the east to Fort Simpson on the Mackenzie, the small northern form of the monax group of woodchucks barely enters the extreme northeastern corner of North Dakota. One specimen collected at Pembina in 1887 was identified by Howell as belonging to this form. It was taken on the North Dakota side of the river, but after it had been seen to swim across from the Minnesota side. In 1915, Kellogg reported a few woodchucks at Pembina, but did not obtain any specimens. The river at this point has considerable timber along both sides, and woodchucks are likely to pass back and forth freely, if not during the summer, they certainly would early in spring before the river breaks up. At Walhalla they are fairly common, but by October 1, 1919, they had all denned up for winter. One found in the bank and later mounted was evidently the little dark-colored canadensis.       General habits.--The only difference in habits between this form and the more southern rufescens may be attributed to climate and environment. With a longer winter, more snow, and a somewhat different set of plants from which to draw their food supply, these [p.70] rodents readily adapt themselves to local conditions. In the shorter season they are still able to lay up sufficient fat to carry them through the long, cold winters, and in spring they come out of hibernation even while the snow is still deep. As early as March 18, in northern Minnesota, they sometimes come out on 4 feet of snow, making tracks in the soft, melting surface or on the frozen crust and visiting back and forth from one burrow to another, opened out through snow tunnels. This is the mating season, and, according to Seton (1909, vol. 1, p. 426), the four or five young are born about the end of April. Over this great northern country they are generally harmless, except where locally they come in contact with fields and gardens. Family MURIDAE: Old World Rats and Mice Rattus norvegicus (Erxleben) Brown Rat; House Rat; Wharf Rat [Mus] norvegicus Erxleben, Syst. Regni Anim., p. 381, 1777.       Type locality.--Norway, where introduced in 1762.       General characters.--Size, variable; ears, small; nose, long and pointed; tail, long, nearly naked, and minutely scaly; color, dull brownish-gray above, light or whitish below, occasionally bluish black. Measurements of average adults: Total length, 415 millimeters; tail, 192; hind foot, 43; measurements of a large individual, 468, 212, and 44, respectively. Weight of large individuals, about 1 pound.12       Distribution and habitat.--The familiar house rats are not native to America, but came over on ships about 1775, and since then have spread over most of this country, except some of the arid interior. They follow railroads and settlements into every part of the country where they can find food and cover, preferring the buildings and habitations of man. It is safe to say that they first entered North Dakota with the early steamboat traffic up the Missouri River.       In 1833, Maximilian (Wied, 1839-1841, Bd. 2, pp. 72, 251, 256-257, 1841) found them a great pest among the grain stores of the Indians at Fort Clark. He says that in the loft of the stores of the fort were 600 to 800 bushels of maize that a great number of Norway rats assiduously labored to reduce. They were so numerous and troublesome that no kind of provision was safe from their voracity, but their favorite food was the maize, among which they created much havoc, and it was calculated that they devoured 5 bushels, or 250 pounds, daily. The rats were brought thither by American ships, but as yet had not reached the Minnetaree villages. The following winter, in the house which had been built for him among the Mandan Indians, Maximilian says: "We were molested during the night by numerous rats and put my little prairie fox in the loft above us, where some maize was kept and here he did excellent service."       In 1887, these large rats were abundant at Fort Buford, which was then the terminus of the Great Northern Railway. The old buildings about the fort were filled with them and they were very destructive. Even in the little adobe hotel they were racing about the room every night until caught in traps. At Grand Forks they were said to have only recently arrived and they were not known [p.71] at Pembina, Devils Lake, or Bottineau. In 1909 they were common at Bismarck and Mandan and were said to be at Devils Lake and Rugby Junction, but at Bottineau none had been found. In 1912 they were abundant and troublesome about Fargo, Hankinson, Valley City, Lisbon, Stump Lake, and Grafton. At this time a dead rat was seen at a ranch near Marstonmoor, Stutsman County; Williams reported them at Walhalla, in Pembina County; and within a few years they had begun to infest the country along the eastern edge of the Turtle Mountains. In 1915 Sheldon found them at Fairmount, where they were a great pest around barns and granaries. He says that the farmers who tried to raise poultry had considerable trouble with them, as they took the little chickens at every opportunity. During his visit at the Hoffman farm, two of the farmhands, while transferring a quantity of hay from one section of the barn to another, killed about 100 rats in a few hours. Most of these were about half-grown, only 1 adult being killed. At Lidgerwood, in Richland County, Sheldon found them less common than at Fairmount. On a trip west across the rest of the southern part of the State, however, he did not find any further trace of them.       In 1915 Kellogg found them at Wahpeton, at Grafton, and a few at Oakes, in Dickey County; at Towner, McKenzie County, he reported them as not very common. In 1913 Jewett reported that no trace of them could be found at Sentinel Butte and old settlers living there had never seen them. At Medora, also, none were found. It is probable that the rats will not find their way to the scattered farms over considerable portions of the western and more arid parts of the State for some years to come, but eventually they will undoubtedly cover practically the whole State.       General habits.--So closely have rats been associated with man and his works and for so long a time, that they have become largely parasitic in habits, seeking the cover and protection of buildings and preying upon the food supplies produced and gathered by man. Their sly, filthy habits, mean appearance, and vicious dispositions have not only won the enmity of mankind, but have done much to instill a dislike for other harmless and more attractive native animals with which their name has become associated. To their destruction of property is added the even more serious menace of conveying disease to man. They are by far the most destructive and dangerous of rodent pests and warfare against them should be relentless.       Breeding habits.--A large female rat was sent to the Biological Survey from Fargo by K. F. Bascom, who reported that it had contained 12 well-developed fetuses. This is not an unusual number of young at a birth, and the rats breed so rapidly that under favorable conditions of food supply and protection the rate of increase is enormous. Litters of young are said to be produced sometimes at intervals of 25 days and the breeding season lasts for a large part of the year (Lantz, 1909, p. 16).       Food habits.--Probably no rodents are more omnivorous than rats. They accept anything of an edible nature from fresh or stale meat to young chickens, eggs, fruit and vegetables, grain, nuts, seeds, and even green vegetation. They revel in garbage of all sorts and will often find an abundance of food in city dumps, manure piles, and in the refuse about stables. In a grain-producing region their fondness [p.72] for grain leads to enormous losses, as where an abundant supply is available they merely take the germ and ruin far more than they require for food.       Control measures.--The depredations of these animals are so serious that it is generally found to be good economy to make buildings rat-proof, or as nearly so as possible, by means of concrete, brick, stone, and wire mesh. Where grain and other food can be kept away from them their numbers can easily be controlled, but they are so skilful in burrowing under walls and gnawing through wood that special methods are necessary to exclude them. So adept are they in avoiding traps and poison that a combination of rat-proofing, poison, and traps is often necessary to prevent serious losses from them. The most successful methods of combating them are given in Biological Survey bulletins and circulars, which are available for free distribution. Mus musculus musculus Linnaeus House mouse [Mus] musculus Linnaeus, Syst. Nat., ed. 10, t. 1, p. 62, 1758.       Type locality.--Sweden.       General characters.--Size small, with slender, tapering tail, pointed nose, and rather small ears. Color, brownish-gray above, buffy-gray below, usually without any clear white. Measurements of average adults: Total length, 160 millimeters; tail, 81; hind foot, 19. Weight of adult female, 23.5 grams.       Distribution and habitat.--Troublesome little Old-World mice have become well established over almost every part of North Dakota, in fact through most inhabited parts of North America. So thoroughly have they become dependent on the habitations of man that little is known of their origin and distribution. They followed quickly on the heels of the first settlement of the country and generally appeared within a few years after the establishment of a ranch or farm, even at a considerable distance from other habitations. At almost every place over North Dakota where field work has been done by the Biological Survey, these mice have been reported as common or abundant and troublesome about buildings, and in many cases they have been caught in the fields in traps set for native species.       At Fargo, in 1912, these little mice were so numerous along the edges of fields and roads that it was difficult to catch other species until enough trapping had been done to reduce the numbers of the house mice. Near Williston, in 1913, they were abundant at the ranches and very destructive of grain in the bins and sacks. In the bunk house at one of the ranches the mice kept up a racket all night, and in the morning there were little piles of oat shells on the floor where grain had been brought in and eaten. Their musky odor was very evident in the room, leaving no doubt as to the identity of the species, and one was shot as it ran across the floor. At Kenmare, in the northwestern part of the State, they were abundant both in town and in the weedy bottomland, where many were caught in traps. At Mandan, in 1913, Jewett found them abundant in town and also on rough slopes in the surrounding fields to a distance of 2 miles from town. At Glen Ullin he caught them on the sides of buttes a mile from town, and also in the tall grass along the creek [p.73] bottoms. At Sentinel Butte they were found at almost every ranch; also at Fort Clark, and around Oakdale in the Killdeer Mountains. Specimens were also taken at Buford, Bismarck, Cannon Ball, and many other localities over the State.       General habits.--House mice are generally imported in boxes and loads of goods where they have made their nests, and are carried long distances on trains or in wagons. They prefer the protection of buildings, but when they have become numerous overflow into the surrounding fields and country wherever food and cover are to be obtained. They breed and increase with great rapidity and but for their natural enemies would soon overrun the fields and render agriculture unprofitable. Cats are generally used to keep down their increase, but serve as a very limited check. The native owls, hawks, and weasels, however, do much to control their abundance.       In habits the mice are often filthy, running through the dirt of stables and cellars and then over the food in pantries or kitchens, in this way not only destroying food but distributing disease germs.       They are so slender that they can slip through cracks and narrow openings into places supposed to be proof against their entry, and they will also gnaw through a considerable thickness of wood to get at food or grain that is stored. Concrete, plaster, and fine wire mesh are the best protection against their inroads, but in spite of all efforts it is often necessary to resort to poison and trap in order to destroy them. Inverted boxes covering poisoned grain, with small openings through which larger animals can not pass, may be kept in buildings where mice occasionally enter and many may be destroyed in this way. Directions for preparing poisoned bait, as well as for trapping these pests, will be furnished by the Biological Survey, United States Department of Agriculture, on request. Family CRICETIDAE: White-footed Mice, Harvest Mice, Grasshopper Mice, Wood Rats, and Voles Peromyscus maniculatus osgoodi Mearns Osgood White-footed Mouse (Pl. 11, fig. 1) Tepa-uti13 of the Omahas (Gilmore) Hesperomys leucopus nebrascensis Mearns, Bul. Amer. Mus. Nat. Hist., vol. 2 (1887-1890), pp. 285, 287, 1890 (not of Coues, 1877). Peromyscus maniculatus osgoodi Mearns, Proc. Biol. Soc. Washington, vol. 24, p. 102, 1911.       Type locality.--Calf Creek, Custer County, Mont.       General characters.--One of the smaller-sized white-footed mice, of rather pale buffy ochraceous color over the upper parts and pure white below; tail sharply bicolor. Immature individuals are more bluish-gray above, only the adults being buffy ochraceous. Average measurements of adults: Total length, 158 millimeters; tail 64; hind foot, 20. Weight of adult male, 20.5 grams.       Distribution and habitat.--The little native white-footed mice are abundant over the western, drier part of North Dakota east to the Missouri River Valley, thence grading insensibly into the darker eastern form bairdi. The area of intergradation is mainly east of the river, including such localities as Kenmare, Minot, Napoleon, and Linton. In the Missouri Valley the mice seem to be typical [p.74] of this western form. They are abundant in almost every locality and situation over the areas they inhabit. At Fort Buford, in 1887, they were found abundant, and again in 1913 about equally abundant over the prairies and Badlands buttes, in marshes, and in wooded bottoms. In 1910 Anthony reported them there as numerous in the brush, among the rocks, and on the hills and prairies. At Fort Clark, Jewett caught them in traps set over a wide range of country, but most commonly among rocky buttes and around wheatfields. Along the Little Missouri River from Medora to Quinion he caught them wherever his traps were set, in the willows along the river, in the sagebrush, and on the rocks and hills. At Oakdale, in the Killdeer Mountains, he also caught them in traps set on rocky slopes, in the brush, along the creeks, and in the swamps around springs. At Sentinel Butte they were found on the open prairie, among rocks on the buttes, and in wet grassy places at the edges of ponds. At Glen Ullin he found them very common, living in burrows and among rocks all over the country. At Mandan he caught them in the brush, along the river, in rocks on the open prairie, and along fences or borders of wheatfields. At Cannon Ball, Sheldon reported them as inhabiting the grainfields principally, but also the arroyos and sandy bluffs.       These reports indicate great abundance, a continuous distribution, and perfect adaptation to a great variety of environment.       General habits.--These beautiful little animals, with large eyes, long whiskers, and large, expressive ears, show much intelligence by adaptation to a great variety of conditions of life, but are nervous and timid and do not readily accept conditions of domestication. In the woods they climb trees and are fond of living in hollow logs or other cavities, but in the Badlands they find safe retreats among the rocks, cliffs, and clay banks, and on the prairies they live in natural cavities or abandoned burrows of other animals. They probably dig burrows for themselves when necessary, but usually are able to find plenty of those abandoned by pocket gophers and other burrowing rodents. They often live in the driest situations and seem not to be dependent on a permanent water supply, although they have no objection to wet or marshy ground. Strictly nocturnal in habits, as is indicated by their large, dark eyes, they are rarely seen except when disturbed in their diurnal retreats, and although abundant, they are not generally well known. The plow often turns them out of their underground nests and they are frequently disturbed when land is cleared; after haying and harvesting they are found in haycocks or grain shocks that have been standing for some time in the fields. Wherever they take up their abode they quickly make a soft nest of fine plant fibers and seem perfectly at home if shelter and food are obtainable. They are often so numerous as to be very troublesome to the naturalist in search of rare specimens, as they fill his traps night after night until they have been thinned out.       Near the mouth of the Cannonball River one evening while it was still light enough to see fairly well, a brown-backed old Peromyscus ran out from under a stone. It darted about nimbly from one stone to another, then stood still and watched for half a minute, its big ears and bright eyes giving it a very animated expression. This [p.75] is one of the few times when these little mice have been seen out foraging of their own accord before daylight was entirely gone. They will often run over a person, however, while he is sleeping on the ground, and there is generally plenty of evidence of their presence about camp in the morning.       In winter on soft snow their tracks may be found leading from tree to tree, or bush to bush, or from one weed to another where they have run in search of food, but most of their tracks lead to or from holes in the snow which connect with tunnels under the snow or cavities under ground.       At Mandan and Cannon Ball late in October, 1919, the writer followed many of their tracks to nest cavities in the ground, and dug down and caught the mice in the hands. All were in old stump holes, where cottonwoods had decayed and left rotten wood or hollow spaces deep in the mellow soil of the forested bottomland. At a depth of 6 inches to a foot below the surface, nests of soft leaves and plant fibers were found, lined with cottonwood cotton and rabbit fur, and in these nests from one to four of the mice were comfortably housed for the winter. When disturbed they came out to see what was the matter and they were tied in a handkerchief or gloves and carried home for further study. Even, when the temperature was -15° F. and the snow 11 inches deep the mice were out making long lines of tracks at night, in following which much was learned of their food and other habits. They seemed to know where to go directly to every seed-laden tree, vine, bush or weed, and whether to climb up or dig down to get the seeds or fruit.       Breeding habits.--The females usually bring forth four to six young at a litter and they apparently breed several times during the summer. Their increase is rapid, and but for numerous enemies their abundance would be far greater than at present.       Food habits.--The white-footed mice are dainty feeders. The contents of many stomachs examined show a mass of clean white material so carefully selected and finely masticated that there was no trace of shells or hard parts to show from what kinds of seed it came. Most of their food is of various seeds and grain, although sometimes a bit of green vegetation, some bright-colored flowers or berries, or a few insects are eaten. At Mandan the mice were feeding largely on the bullberries, which they gathered nightly from the well-laden bushes, apparently eating both the sweet pulp and seed kernels. There were bits of scarlet skins scattered over the snow and the mouse pellets neatly deposited in a cavity not far from the nest were mostly colored dull scarlet by the berries, while some of the seeds were found in mouse caches. From one cache near the nest a handful of seeds was saved and brought back for identification. Among them were seeds of chokecherry, woodbine, wild grape, smilax, buffaloberry, hosackia, dogwood, bindweed, two species of knotweed, two of pigweed, ragweed, Russian thistle, black henbane, sedge, barnyard grass, and dropseed grass. The mice seem fond of any kind of camp food, as flour, meal, oatmeal, grain, meat, butter, bread, or crackers. Rolled oats generally make the most attractive bait with which they can be tempted into traps. They are active throughout the year and do not put on fat to carry them [p.76] through the winter, but instead store up a limited supply of seeds and grain for winter use or for bad weather when they can not come out and run over the surface of the snow in search of food.       Economic status.--The small toll these mice take from grainfields would not in itself cause very serious loss, but added to that of many other species the constant drain on farm products is sometimes serious. They cut some grass in the meadows and eat the seeds of many grasses, thus, to some extent, retarding the forage reproduction and in places taking away so much seed as to form a serious check on the reproduction of other vegetation. Probably more than any other animals they check reforestation, whether this depends upon naturally or artificially sown seeds. So small, so numerous, and so widely distributed are they that they are not easily controlled, except by their natural enemies, which are numerous. They are favorite prey of all small owls and even of many of the larger owls, and form an important article of diet for weasels, skunks, badgers, foxes, and such of the other small predatory species as occur within their range. Reasonable protection of the species that prey upon them, especially the owls, forms the simplest and most effective means of keeping down their abundance. Peromyscus maniculatus bairdii (Hoy and Kennicott) Baird White-footed Mouse Mus bairdii Hoy and Kennicott, Rpt. Comr. Patents. [U. S.] 1856, p. 92, 1857.       Type locality.--Bloomington, McLean County, 111.       General characters.--About the size of osgoodi, but colors much darker, often dusky along the back, and less buffy or ochraceous; underparts, white. Measurements of an average specimen: Total length, 150 millimeters; tail, 60; hind foot, 19. Weight of adult male, from Fargo, 18.5 grams.       Distribution and habitat.--From Ohio and Oklahoma the little dark-colored white-footed mice (bairdii) extend over the eastern half of North Dakota and into southern Manitoba. In their typical form they do not reach west of the Missouri River, but at about the one-hundredth meridian they grade insensibly into the paler, more buffy osgoodi. There are specimens from almost every locality where collecting has been done in eastern North Dakota, from Hankinson to Pembina and westward to Linton, Towner, and Kenmare. They are found on the tall-grass prairies in the area of humidity and ample cover, where their dark color is protective in the grassy and weedy shadows.       General habits.--These little mice, like their western form, osgoodi, are the most abundant and generally distributed mammals of their region. They live in a great variety of situations, from brushy weedy bottoms in the woods, half-dried tule marshes, and dead-weed rows along the roadsides to the middle of grainfields and out over the wide, open, grassy prairie, making nests and homes in hollow logs or trees, in underground cavities which are found, or if necessary, excavated, or under any cover that will offer a dry bed. From osgoodi of the drier, more open plains farther west, they differ in habits only in adaptation to more abundant plant growth and more nearly continuous grainfields.       Where food is plentiful they congregate in great numbers, but where it is scanty they become scarce. At Stump Lake, in a line [p.77] of traps set along the sandy beach, 16 of these mice were caught in one night where they were finding a choice food supply in the cockleburs which covered the sandy ground. At Crosby the writer found them feeding largely on little caterpillars. At Valley City many were caught in the rows of tumbleweeds or Russian thistles along the fences, where they were feeding on the seeds of these weeds under the cover of which they found ample protection. Eastgate reported 19 caught in his line of 41 traps the first morning after he camped near this place. They are often found in the haycocks and wheat shocks in the fields, and if these are left for a considerable time the mice are sure to make their nests in them and do more or less mischief.       In breeding and food habits these mice are essentially the same as the western osgoodi. Their injury to crops is somewhat greater because of the more general cultivation of land over their range. Their enemies are practically the same and if only given a fair opportunity will keep down the too rapid increase of these interesting but destructive little rodents. At Fargo in the well-cleared city parks not a mouse could be caught, while in the uncleared woods near by, where weeds and bushes protected them from the little owls, these mice filled the traps the first night. Peromyscus leucopus noveboracensis (Fischer) Northern White-footed Mouse; Deer Mouse [Mus sylvaticus] noveboracensis Fischer, Synop. Mamm., p. 318 (p. 14, δ.), 1829.       Type locality.--New York.       General characters.--Largest of the white-footed mice of North Dakota, with relatively long tail and dark colors; upper parts of adults, dark buffy or tawny-gray, with more blackish or dusky about face and ankles than in aridulus; underparts and lower half of tail, pure white. Young and immature, bluish gray or plumbeous. Measurements of adult male from Fargo: Total length, 185 millimeters; tail, 78; hind foot, 22. Weight, 27.5 grams.       Distribution and habitat.--The northern form of the white-footed mouse is the common deer mouse or woods mouse of the northeastern United States and southeastern Canada from Nova Scotia to eastern North Dakota. It is largely a forest species, rarely found far from forest or brushland and seems not to extend over the open prairie country. Specimens taken at Fargo, Moorhead, and at Manvel, just north of Grand Forks, are fairly typical of this eastern form and certainly referable to it rather than to the paler aridulus of the Missouri Valley. They probably have a continuous range along the timber of the Red River Valley, but seem not to be abundant.       General habits.--Deer mice are largely forest dwellers, but have a wide range of adaptation and will go anywhere that safe cover and an attractive food supply lead them. From their original homes in hollow trees and logs or in the ground under old trees and stumps they readily follow the rail fences and brushy fence rows around the fields, taking up their quarters under grain shocks, haycocks, or haystacks, or entering new buildings erected in the clearings. They are great climbers and will run up the trunks and branches of tall trees or up vines and through bushes in search of [p.78] seeds or berries, or over walls and timbers of buildings, with ease and skill.       They are strictly nocturnal and very timid, nervous little sprites, with long, sensitive whiskers and large, thin, delicate ears that are constantly changing form and expression, apparently catching the faintest sounds; their large, prominent black eyes are owl-like in their adaptation to the dark of night. Apparently they can see fairly well in the daytime, but are rarely natural or at ease in the light and lose much of their vivacity and beauty as usually seen when driven out of their diurnal beds or captured and held as unwilling prisoners. They are among the most beautiful and expressive of our small native rodents, to which the unfortunate name of "mouse" is generally applied, and but for their occasional mischief and nocturnal habits might be as interesting and popular as many of our song birds. In fact, they are not without voices, and certain individuals have a fine squeaking trill that might well be called a song. They have many little squeaks and low notes that doubtless mean much to them if little to us. A more common means of communication, however, consists of a rapid tapping with their finger tips on any hard surface or thin material, which produces a sound suggestive of the drumming of minute woodpeckers. These vibrations vary in length and tone and doubtless mean much to them in the way of communication.       Breeding habits.--Nests containing young are frequently found under grain shocks or haycocks, or are plowed out of hollows below the surface of the ground. They are usually as soft, well built, and well lined as those of any bird; and the delicate, naked young are found resting on silk or cotton wool from various plants or on feathers or fur or other equally soft materials provided by the parents. Usually 4 to 6 young are born at a time and apparently several litters are raised each year. The mammae of adult females are six in number, arranged in two posterior or inguinal pairs and a single pair of anterior or pectoral. Often when suddenly disturbed the mother runs from the nest with 5 or 6 young, each clinging securely to a nipple, as she drags them rapidly to some safe cover.       Food habits.--Although the greater part of their food consists of seeds, grain, and nutlets, deer mice also are fond of berries, fruit, and a great variety of such foods as the human species regards as its own and exclusive perquisite. This often leads to trouble, for the little moonlight people get into fields, gardens, granaries, and even cellars and pantries and help themselves, always to the best there is to be had. The fact that they consume large quantities of seeds of noxious weeds is generally overlooked and some easy method of lessening their abundance is sought. Unfortunately, this often takes the form of keeping cats, which may scare some of the mice away, while the cats live largely on song birds. If little owls could be kept instead, there would be no more trouble from the mice. In fact, there are usually enough little owls to keep down the abundance of the mice, where brush, weeds, and rubbish are removed so the mice will have no protecting cover. [p.79] Peromyscus leucopus aridulus Osgood Badlands White-footed Mouse Wiyashpena14 [moon nibblers] of the Dakota Indians (Gilmore). Peromyscus leucopus aridulus Osgood, North Amer. Fauna No. 28, p. 122, 1909.       Type locality.--Fort Custer, Yellowstone County, Mont.       General characters.--A pale buffy western form of the northern white-footed mouse quite distinct from Peromyscus osgoodi with which often associated. Differs in larger size, relatively larger ears and longer, less sharply bicolor tail, and in lacking the tiny white tuft of hair at upper anterior base of ear; otherwise the color and markings of the two species are practically identical. The young and immature are slaty gray. Measurements of type specimen: Total length, 177 millimeters; tail, 73; hind foot, 22. Weight of adult female, 27 grams.       Distribution and habitat.--The Badlands white-footed mice probably have a wide distribution over North Dakota, but are much less numerous than the smaller species and have not been so thoroughly collected. There are specimens from along the Missouri River Valley at Cannon Ball, Mandan, Sather, Fort Clark, Oakdale, Williston, and Buford, but to the eastward there are no more specimens of this group until we find noveboracensis in the Red River Valley. Typical specimens may be expected only from the Missouri Valley and westward. Apparently these are not prairie dwellers, as specimens have been taken only in timbered flats along the streams.       General habits.--At the mouth of the Cannonball River they are comparatively common and in August, 1915, Sheldon collected a series of 17 specimens in the forest of the river bottoms. In June of the following year the writer found them common there in the forest and caught them in traps set in thickets and at the bases of hollow cottonwood trees on the river bottoms. In one hollow tree, about 4 feet from the ground, one of the mice was found in a well-made nest lined with the silky down from the cottonwood seeds, and in another hollow cottonwood an old female was caught well up in the cavity of the trunk. At Mandan late in October 1919, when the ground in the bottomland woods was covered with 11 inches of soft snow, some of these mice were tracked to their nest cavities in hollows where old stumps had decayed. In one of these honeycombed, rotten-wood cavities a nest was found about a foot below the surface of the ground and four of the five occupants were caught as they came out. There were an adult male, two adult females, and two immature of the year in the blue coats. They came out of a nest in one of the side cavities where a root had decayed, but they had free access to all parts of the porous wood from deep in the ground to the leaf-covered surface. Curiosity seemed to bring them up to see what was disturbing their home and they were caught and put in handkerchief and gloves and kept [p.80] for many months as interesting pets. The nest was a large, soft, warm ball of dry leaves and plant fibers lined with cottonwood cotton and was evidently the home of a family. In captivity they were very friendly and sociable, making a happy family in one nest with four of Peromyscus maniculatus osgoodi.       Like other members of the group, Badlands mice are strictly nocturnal in habits and are rarely seen except as caught in traps for specimens or driven out of their diurnal retreats. When seen by daylight, they are beautiful little animals with beady black eyes, large expressive ears, and long trembling mustaches, which give them a keen and animated expression. They are quick and agile in habits, running with long leaps, and climbing rapidly and skillfully over the trunks and branches of trees. In fall they do not become very fat, but lay up supplies of winter food and continue active throughout the coldest weather. Their delicate lines of tracks may often be seen from tree to tree, or from some old log to a stump or brush heap, or centering around a hole in the snow through which they have access to the surface of the ground, where their winter nests and stores are hidden. Over much of their range they are found only in limited numbers, but in certain localities are exceedingly numerous and at times become very mischievous around outbuildings and granaries. As they avoid the open country, they are less mischievous in grainfields than are their smaller and more generally distributed relatives. They are not usually considered a serious pest, but locally they add their little to the constant tax of such rodents upon farm crops. Reithrodontomys megalotis dychei Allen Prairie Harvest Mouse (Pl. 12) Reithrodontomys dychei Allen, Bul. Amer. Mus. Nat. Hist., vol. 7, p. 120, 1895.       Type locality.--Lawrence, Kans.       General characters.--A slender little mouse with large ears; buffy brown upper parts, and white underparts, distinguished from the house mouse, which it somewhat resembles in size and color, by slenderer and not noticeably tapering tail, and by pure white feet and underparts. From both the house mouse and white-footed mouse it is still better distinguished by a longitudinal groove down the front surface of each upper incisor. Average measurements of adults: Total length, 133 millimeters; tail, 52; hind foot, 16.       Distribution and habitat.--From the Upper Sonoran plains and prairie regions of the Central States the little prairie harvest mice come into North Dakota along the Missouri and Dakota River Valleys. There are specimens from Cannon Ball and Fort Clark in the Missouri Valley, Ellendale, Ludden, and Oakes in the Dakota Valley, and from farther east at Lidgerwood and Hankinson, and Fargo in the Red River Valley. At Cannon Ball, Sheldon found the mice quite common over the prairie and on sandy flats, but more abundant along the brushy borders of grain fields and even out in the fields. At Fort Clark, Jewett caught four in traps set near small burrows at the edge of a wheatfield and on the high prairie. At Ellendale, Sheldon found them fairly common in grass along the fences, in brushy places, and occasionally in wheatfields, and at Lidgerwood he took [p.81] two specimens in tules at the edge of the lake. At Hankinson, W. B. Bell found them common in the tumbleweeds along the fences on sandy soil, and at Fargo Murie took four specimens on the grassy river bank at the edge of a field.       General habits.--These little harvest mice live mainly on the surface of the ground under cover of grass and low vegetation. Their tiny runways may be distinguished from those of meadow mice by being narrower. The harvest mice like the open ground, but must have sufficient cover to protect them from a host of enemies overhead. In places they apparently live in small burrows, but generally their trails seem to terminate at neat little nest balls on the surface or in low bushes and weeds. The nests are rarely found more than 8 or 10 inches from the ground, and more often they are lightly placed on the surface under some ample cover. At Hankinson, a harvest mouse was frightened from a pretty little grass nest in a lock of hay; the nest was a compact ball of fine grass lined with soft fibers, with a tiny opening at one side for a doorway.       Breeding habits.--Usually four to six young are brought forth and cared for in these birdlike nests, but at Oakes, on June 4, Eastgate took an old female that contained seven embryos. Apparently they breed more than once during the season, and in places where there is abundant food and good cover they sometimes become very numerous.       Food habits.--The principal part of the food of harvest mice consists of seeds, largely of grasses, which are found cut in small sections and drawn down until the seed-laden tops are within reach. The mice are fond of rolled oats and other grains used for trap bait and their presence in the fields indicates a fondness for the growing grains. They do not become fat in fall and evidently do not hibernate.       Economic status.--These little mice cover so small a part of North Dakota that they are of slight economic importance, but in areas where they are widely and abundantly distributed their inroads on the grain and forage production materially help to swell the total of rodent depredations. Although they are so small that any artificial means of combating their mischievous tendencies would be futile, effective check is constantly kept on their overabundance by such predatory birds and mammals as small owls, hawks, and probably crows, jays, magpies, and butcherbirds, as well as by weasels, skunks, and badgers. Onychomys leucogaster leucogaster (Wied) Maximilian Grasshopper Mouse (Pl. 13, fig. 1) Michtika of the Mandans (Maximilian)15; Michtik-tak of the Mandans (Gilmore). Hypudaeus leucogaster Wied, Reise in das Innere Nord-America, Bd. 2, p. 99, 1841.       Type locality.--Fort Clark, Oliver County, N. Dak.       General characters.--Somewhat resembling the white-footed mice, but recognized at once by larger size, heavier build, short, thick, tapering tails, and [p.82] smaller ears. Legs also shorter and feet heavier, to harmonize with their entirely ground-dwelling habits. Upper parts dark drab brown, darkest along the back; underparts and lower half and tip of tail white; Immature specimens, dark slaty gray; occasional individuals nearly black. Average measurements of adults: Total length, 164 millimeters; tail, 42; hind foot, 22.       Distribution and habitat.--In his revision of the genus Onychomys, Hollister (1915, p. 434), refers all of the specimens from eastern North Dakota to the typical dark-colored subspecies leucogaster as described by Maximilian, Prince of Wied, from specimens taken by him at Fort Clark in 1833. The species as thus restricted covers little more than the eastern half of North Dakota, reaching slightly into western Minnesota and northeastern South Dakota and northward into southern Manitoba. There are specimens from Fort Clark, Linton, Grace, Devils Lake, Minot, Pembina, Sherbrooke, and Hankinson. None has been taken in the immediate valley of the Red River nor in the Turtle Mountains, but apparently the species covers the rest of the State either in this dark form or in the paler western form. It is strictly a prairie animal occurring neither in the forest nor the dense thickets, but scattered over the open country in bare and exposed situations as well as under the cover of grass, weeds, and low scattered shrubbery. Though widely distributed it is never very abundant locally.       General habits.--These anomalous little rodents, like the badger and other predatory animals, are apparently wanderers, to some extent, scattering out singly to cover their hunting grounds to the best advantage. Traps set at different kinds of burrows and holes in the ground over the prairie, under a variety of conditions, catch them apparently at random. Sometimes a whole family will be caught in a little thicket or weed patch or a few may be caught every night along a weedy fence row, where they evidently are hunting for their nocturnal prey, but there seems to be no specific place to look for them and rarely is there an trail, burrow or sign found that can be unmistakenly attributed to them. Most of the specimens taken are caught by accident in traps set for other species. At Fort Clark, Jewett caught them at small holes or the deserted burrows of ground squirrels and pocket gophers over the prairie or along the edges of fields. At Hankinson specimens were taken among the sandy dunes, often on bare sand, but also in the rows of tumbleweeds along the fences. Some were caught in burrows of other animals and some in burrows that may have been made by the mice themselves; others in trails made by scraping with the foot in the sand for a distance of 8 or 10 feet; like many other species of mice, they will follow such a trail and are easily caught in traps set across it. Often they are caught in old badger holes, where apparently they are foraging for insects.       While mainly nocturnal they are less strictly so than the white-footed mice, and the writer has seen them running through the weeds in the daytime and on one occasion he shot one about 8 a. m. Generally they are unknown to residents of the country, who probably mistake them for the common white-footed mice. Many are doubtless thrown out of their burrows by the plow, but no one seems to have recorded anything regarding their habitations or home life. At night their fine, prolonged whistle, almost insectlike in pitch and quality, was often heard around the camps, but nearly the whole [p.83] summer of 1887 passed before it was discovered to what form the voice belonged.       Hibernation.--In fall these mice become moderately fat, but whether they hibernate in this climate is still a question. Farther south closely related species are caught at all seasons, but in a region well covered with snow for a large part of the winter they would have difficulty in procuring a food supply, as apparently they do not lay up stores or make any provision for winter.       Breeding habits.--An old female caught at Grace, July 2, 1912, contained four large embryos, which seems to be the usual number of young. The mammae of the females are arranged in three pairs, two pars of inguinal and one pair of pectoral, and probably like other species of the genus the young are occasionally five or six in number.       Food habits.--Grasshopper mice are omnivorous in their tastes, readily accepting rolled oats, bread, cake, cheese, seeds, or grain as trap bait, but show a decided preference for animal food, as indicated by the examination of a great number of stomachs. At Fort Clark, the type locality, Jewett took a fine series of specimens, both old and young, in traps set around the edges of wheatfields and baited with fresh meat or bacon. He says some were taken in meal-baited traps, but that they prefer meat. Grasshoppers, crickets, beetles, and a great variety of other insects are found in their stomachs, also often the flesh and hair of other mice which have been caught or found dead. At Hankinson many of the other mice in the traps were eaten and the stomachs of grasshopper mice caught near by often proved that they had been the trap robbers.       Economic status.--The only complaint of these mice doing any mischief seems to come from their discoverer, Maximilian (Wied, 1839-1841, Bd. 2, p. 101, 1841), in 1833, at the Mandan villages, where he reported them as common over the prairie and in winter coming into the Indians' houses, where all sorts of stores were kept. He says the Mandans call them "mihtick," as they do all kinds of mice. There is no doubt that Maximilian knew the species, as his description is full and perfect, but it is suspected that the mice which did the mischief in the Indian stores were mainly the white-footed species, which also were abundant there. At Fort Berthold, in 1872-73, Doctor McChesney (1878, p. 206) reported them abundant and inhabiting the underground caches of the Indians. Before a definite statement can be made as to the destructiveness of these mice, more complete knowledge of their habits will be necessary. The great numbers of injurious insects eaten by them and their destruction of some other and more troublesome species of mice should class them among the highly beneficial mammals. A more detailed study of their habits is likely to prove of practical value. Onychomys leucogaster missouriensis (Audubon and Bachman) Audubon Grasshopper Mouse Mus missouriensis Audubon and Bachman, Quad. North Amer., vol. 2, p. 327, 1851.       Type locality.--Fort Union (now Buford), N. Dak.       General characters.--Very similar to leucogaster, but slightly smaller and much paler, the upper parts being buffy brown, darker in winter pelage, and underparts white; immature specimens, slaty gray. Average measurements of adults: Total length, 150 millimeters; tail, 39; hind foot, 21.       [p.84] Distribution and habitat.--The paler form of the grasshopper mouse comes into western North Dakota from a wide range over the semiarid plains of Montana, Wyoming, and Saskatchewan. There are specimens from Buford, Dickinson, Glen Ullin, and Cannon Ball. Although few specimens have been taken, the mice undoubtedly cover the whole western part of the State, grading insensibly into the darker-colored leucogaster near the type locality of that species, Fort Clark. They belong to the short-grass prairie or plains of the semiarid region and seem to be generally distributed over the open country.       General habits.--One of these mice brought to Audubon at Fort Union on July 14, 1843, was figured and described in his (Audubon, 1851-1854, vol. 2, p. 327, pl. 20-C, 1851) Quadrupeds of North America. Thus the species was made known and named, but nothing whatever learned of its habits. In 1887, with instructions to make a special study of the habits of this mouse, the writer visited Fort Buford. With such crude collecting traps as were available at that time a considerable number of specimens was obtained, most of them being caught alive in little tin box traps. They were common over the hills and prairies, living in burrows of other small animals, as pocket gophers, ground squirrels, other mice, and even in old badger holes. Some were caught at the burrows of the pale field mouse Microtus pallidus, which they were probably hunting for food. Some of the fresh burrows in which they were caught may have been of their own construction, but probably were the burrows of other mice, to which they were only paying visits in order to capturing prey. The bait first used for them was cheese and doughnuts, but since then a bit of fresh meat has been found much more attractive.       One of the mice caught in a box trap was not quite full grown and seemed so gentle and interesting that a cage was made for it and it was kept for some months. From the first it was not in the least alarmed and when handled never offered to bite nor struggled to escape, although in the cage at times it became frantic in its efforts to get back to its natural haunts. Unless very hungry it would sleep all day, but on waking up in the evening, after stretching and gaping and blinking for a while, would become thoroughly roused and eager to get out and hunt for its supper. It did not like a bright light and would show signs of discomfort by blinking its eyes, but, with its box faced away from the light, was very bright and animated. At a touch on the box it would come to the front and eagerly take whatever food was put in between the wires. Any insect put inside was quickly caught, and even flies would rarely escape it.       From the trap line the writer always brought back plenty of food for the mouse and greatly enjoyed watching it eat the different kinds of insects. In one forenoon it ate 16 crickets, 11 grasshoppers, 1 spider, 1 black bug, and 1 big fly. Its favorite food seemed to be crickets, and it would never touch anything else while there was a cricket in its box. Next to crickets it liked grasshoppers or flies, but did not seem to care much for beetles, although it would eat any kind offered including some ladybugs and a small black species that was common under sticks and stones, and it seemed to relish a potato bug found [p.85] for it, as it ate all but the wings and legs. One day it ate 12 crickets and 1 spider in 7 minutes; and a little later, 11 grasshoppers, 4 crickets, 1 black bug, and 1 large fly, making 29 large insects and 1 spider eaten in about 4 hours, and it still seemed hungry. On another day the mouse ate 28 crickets, 15 flies, 8 grasshoppers, and 2 beetles, in all 53 insects in less than 12 hours. It seemed to relish a common gray moth and enjoyed a black hornet until it came to the tail, when the stinger evidently pricked its nose. Ants were the only insects it ever refused and a few of these in its box would make it violently frantic.       To see it eat a large grasshopper was amusing. The mouse would hold the grasshopper upright between its hands and begin on the head, when a few vigorous kicks of the grasshopper would tip it over backward; but it would never let go until the head was eaten off and the body devoured. The wings and legs would drop off as it progressed, and if the mouse was still hungry they would be eaten later. If a number of grasshoppers were put into its box at one time, it would first bite off the heads of all, so that none would escape, and then finish them at its leisure. One day the mouse killed and ate a small frog, but did not seem to care much for it. Only when very hungry would it eat seeds and green leaves of plants.       It pounced like a cat upon a dead white-footed mouse dropped into its box, caught it beside the head near the ear, and began biting with all the ferocity of a carnivore. The bones could be heard to crack, and when taken out a small hole was found broken through the base of the skull. Its teeth had penetrated well into the brain. The dead mouse was returned to its captor, which began to tear and pull off strips of skin and flesh from the neck, shoulders, and head, and ate both of its eyes. Another mouse that was put into its cage was treated in the same way, and a song sparrow that had been accidentally killed the mouse bit through the head and then partially ate. It ate part of a mouse of its own kind, thus proving to be cannibalistic as well as carnivorous. It was fond of bits of fresh meat and especially of brains that were given it while specimens were being prepared.       The fierceness shown in attacking mice indicated a habit of capturing and killing these animals in their free state. In spite of its savage disposition and carnivorous tastes, it was the gentlest rodent to handle, as well as one of the most interesting and attractive pets; others of closely related species generally show similar dispositions.       Breeding habits.--On May 30, 1910, H. E. Anthony caught an old female at Buford, containing four embryos. Little is known, however, of the breeding or other home habits of these mice.       Hibernation.--One adult caught at Fort Buford in September was so fat as to suggest preparation for hibernation, but the fat was not distributed in a thick layer under the skin as is the case in most hibernating mammals. The question of their hibernation in the North is still to be determined.       Economic status.--Grasshopper mice make extremely interesting pets and their field of usefulness seems well worth careful investigation. They might in certain cases be used to advantage in keeping down insect pests in greenhouses and other buildings, and it is probable that their carnivorous propensities would render them valuable in combating other more destructive mice. [p.86] Neotoma cinerea rupicola Allen Pale Bushy-tailed Wood Rat (Pl. 13, fig. 2) Neotoma rupicola Allen, Bul. Amer. Mus. Nat. Hist., vol. 6, p. 323, 1894.       Type locality.--Corral Draw, southeast base of Black Hills, S. Dak.       General characters.--About the size of the wharf rat, but of very different appearance. Ears and eyes, large; mustache, very long; tail, bushy, almost squirrel-like; fur, long and soft; expression, animated. Color of upper parts, pale pinkish buff; the feet and underparts, white. Young, light buffy gray; tails, mostly white, not buffy. Measurements of average adults: Total length, 349 millimeters; tail, 144; hind foot, 43.       Distribution and habitat.--Wood rats are scattered over the State from the Missouri River Valley westward, or throughout the Badlands region. Just where they grade into the slightly darker cinerea is not entirely worked out, but probably somewhat west of the line between North Dakota and Montana. They are nowhere abundant or even common, but seem to be generally distributed wherever there are Badlands cliffs and ledges to afford suitable homes and protection from their enemies. Their range can hardly be considered continuous, but they have managed to scatter from one cliff to another until they have occupied almost every suitable rocky slope. There are specimens from Mikkelson, Oakdale, Wade, and the Little Missouri River near the former Dakota National Forest, and their unmistakable signs have been found at Marmarth, Deep Creek, Medora, the White House Ranch (18 miles southeast of Williston), and near Goodall and Parkin. A few were reported at Cannon Ball, and Doctor Bell caught two at Wade. In 1833, Maximilian (Wied, 1839-1841, Bd. 1, p. 438, 1839; Bd. 2, p. 89, 1841) reported them in the forest at Fort Union, at Cedar Island, and at Fort Clark. In 1869 Cooper (1869, p. 296) reported them in the rock bluffs that border the Missouri River above Great Bend. In 1872, Doctor Allen (1875, p. 42) found them more or less frequent in the timbered portions of the streams west of Fort Rice. Their principal strongholds are cliffs and ledges, but they also occupy the cottonwood forests in the stream valleys, where hollow logs and trees often offer choice homes, and dense masses of bullberry brush and impenetrable cover afford the protection necessary for their existence. They are quick to find and occupy buildings of any sort, and for this reason their presence is soon made known wherever they occur.       General habits.--In habits as well as appearance wood rats are entirely unlike the Old World rats, and it is unfortunate that they should have to bear the odious name. Their long mustaches and big ears and eyes give them an even more animated expression than that of the squirrels. While mainly nocturnal, they are occasionally see by day when disturbed from their cozy nests in cabins or cliffs. They are timid animals, with practically no means of defense against numerous enemies except the barricades of their dwellings. Their favorit home is a cleft in the rocks where narrow cracks admit them to deeper cavities or where the openings can be blocked with sticks, stones, and rubbish to keep out larger animals. This building habit has become so fixed that their first instinct is to gather building material wherever they are. Even where it is not [p.87] needed they often pile up heaps of rubbish, sometimes in front of their doorways, sometimes in large openings that they could never hope to fill. These accumulations remain for years in the eaves and caverns, or hollow logs, trees, or cabins, where the wood rats have been; as also do the long black pellets of excrement. In buildings to which they have gained access all small articles of a convenient size are usually gathered into one corner to protect the nest, but sometimes they are piled into a box, cupboard, or stove, or heaped up in some doorway that the rats would like to be able to close. In occupied buildings they are noisy and mischievous, but may soon be discovered and disposed of.       Roosevelt (1900c, pp. 66-67), on returning to his ranch on the Little Missouri when it had been unoccupied for some months, found that "within doors the bushy-tailed pack-rats had possession and at night they held a perfect witches' Sabbath in the garret and kitchen." Half the cotton had been dragged out of a mattress and made into a big, fluffy nest that entirely filled the oven. In 1909 one of their old rubbish houses was found in the rocks not far from Marmarth and two of the animals were said to have been caught in a house at the edge of town not long before. At Medora, Jewett was told that they occasionally came into the houses, but he could not find any while there, although he found signs of their characteristic work in the rocky ledges about 10 miles farther north, and took two immature specimens near Mikkelson. At Goodall, in the Killdeer Mountains, he was told that they rarely came into buildings, but he obtained two specimens in a ledge about a mile south of town. In the little Missouri Valley, about 25 miles south of Medora, the writer found their signs and old building material quite common in the Badlands gulches, in one of which Jewett obtained a specimen. South of the Missouri River, a little below Williston, old signs were found among the rocks in several places, but no specimens were taken.       Near Goodall, Kellogg reported one caught by a cat on the Goodall ranch, but apparently they were not common in that vicinity. Near Cannon Ball, Sheldon learned of several that had been caught, one in the cellar of an old sod building, and another near the mouth of the Cannonball River in the forested bottoms. At Wade, farther up the Cannonball River, W. B. Bell collected two specimens in a cave in the cedar-covered buttes, and reported them as frequently entering houses and stables of settlers, where they occasionally did considerable mischief.       Breeding habits.--Wood rats, like the other members of the group, probably have two or sometimes four young, which are raised in the soft birdlike nests of their safe retreats. Apparently only one litter of young is raised in a year, so that reproduction is not rapid and there is little danger that these rodents will become very numerous.       Food habits.--Examination of stomachs shows that the food of wood rats consists largely of green vegetation. One taken on the Little Missouri River had green foliage and buffaloberries in its stomach. About their occupied dens there are always traces of various plants brought in for food, and apparently these are brought in for the foliage more than for seeds. The rats, however, are eager for rolled oats, grain, fruit, or bacon used as trap bait and are easily [p.88] caught wherever they occur. They do not become fat in fall nor show any signs of hibernation during the coldest winter weather. Generally they lay up stores of green plants, berries, and seeds, which become dried and well cured for winter food, the dry vegetation forming the great bulk of the winter stores.       Economic status.--In North Dakota wood rats are not sufficiently abundant to be of any great economic importance, although related species in other parts of the country are very injurious to crops, forage, and native vegetation. Here they merely add a feature of interest to the picturesque cliffs of the Badlands, with which they are closely associated. They have a strong and not unpleasant musky odor which, apparently comes from the glands of the skin; it in no way affects the flesh, which is sweet and delicate as that of young rabbits. Although too small to be of any value as game animals, wood rats are in every way suitable for food. There is a possibility of their serving as interesting pets for children, if properly tamed and kept within bounds. Evotomys gapperi loringi Bailey Red-backed Mouse Evotomys gapperi loringi Bailey, Proc. Biol. Soc. Washington, vol. 11, p. 125, 1897.       Type locality.--Portland, N. Dak.       General characters.--In size somewhat smaller than the meadow mouse and of the same general form; ears small, nearly concealed in the long fur; tail, short; legs, short; eyes, small. Whole back, rich chestnut brown, lighter brown in winter; sides, gray; underparts, whitish. Average measurements: Total length, 123 millimeters; tail, 31; hind foot, 18. Weight, 18 to 22 gram.       Distribution and habitat.--Red-backed mice, which represent a small, pale form of a wide-ranging Boreal forest species, occupy the woods and thickets of the Transition-Zone plains region of North Dakota and central Minnesota. Specimens have been taken at Pembina, Grafton, Portland, Larimore, Devils Lake, Stump Lake, Valley City, Kathryn, throughout the Turtle Mountains and Pembina Hills, at Towner, Williston, Buford, Goodall, Elbowoods, Oakdale, Fort Clark, and Cannon Ball. In most of these localities the mice are abundant in the thickets and timber and it is probable that they occupy every suitable locality within the State.       General habits.--In the Turtle Mountains red-backed mice were abundant throughout the woods and brush, and many were caught in traps set under logs, near old stumps, at the bases of trees, in holes in banks, and on smooth ground where the leaves were scraped off to make an easy runway. At Portland, Loring reported them common, many being caught in traps set under logs and roots of trees. At Stump Lake the writer found them numerous in the woods, along the lake shore, and in the thickets out on the prairie. After dark one evening, the writer entered a dense thicket and, scraping away the leaves, set seven traps at random within a radius of 6 feet; the next morning five contained red-backed mice. At Cannon Ball he found the mice common in the forest on the river flats, and at Fort Clark and Oakdale, Jewett found them in similar situations. At the White House Ranch, 15 miles southeast of Williston, Doctor Bell and his party caught several among the dense growth of reeds [p.89] (Phragmites) at the edge of the woods, and at Fort Buford, Anthony found them common in the brushy river bottoms. Unlike meadow mice, they rarely make trails or roadways, but run at random over the leaves and open ground in the woods and bushes, or, preferably, under the cover of thickets and brush, so that little sign of them is noticed, even where they are abundant. They are by no means strictly nocturnal; occasionally the little animals are seen rustling about in the leaves and grass and nearly as many specimens are caught during the day as at night. To some extent they burrow in the ground, but any natural cavities in or under logs, stumps, or trees seem to answer their purpose for homes and nests.       Breeding habits.--Many of the females taken for specimens are found to contain embryos varying in number from 4 to 6, and occasionally 8. These are found at all times through the summer, which would indicate that several litters are raised in a season. As the mice do not hibernate, the breeding season probably covers all but the midwinter period.       Food habits.--The examination of stomach contents of red-backed mice shows usually a combination of seeds and green vegetation. Considerable grass and many small plants are found cut and partly eaten on their feeding grounds and some of these are drawn under the logs and brush where the animals live. They are always eager for rolled oats and will take almost any kind of grain or seed used for trap bait. At Walhalla, Williams caught one in his hands in the daytime, as it was eating piece of bread crust in front of his tent. At Portland, Loring caught a large series of specimens by baiting his traps with meat, and found that occasionally they eat their own kind or other varieties of mice caught in traps where they run. For the greater part of the year, however, their principal food is green vegetation, which they find abundant even under the deep snow of winter, for they plow along the surface of the ground and come in contact with the tender shoots of frozen grass or roots under the leaf mold, or if these are not sufficient they gnaw the bark from bushes and small trees as high up as the snow offers concealment from their enemies above.       There is some evidence that the red-backed mice may be one of the bean-storing species of the Missouri River region. In attempting to discover what animal was really responsible for these caches of food which the Indians find, specimens of all of the small mice occurring at Cannon Ball were trapped, but the only evidence obtained in September, before the mice had begun making their winter stores, was the fondness shown by these mice for the mouse-beans (Falcata comosa). In one bean patch seven traps set on the bare ground, each baited with a half of one of these large juicy underground beans, caught four of the mice in one night. The eagerness of the mice for the beans and their abundance in the localities where the beans grow suggests that the species may be in part responsible for the stores which have been an important food of the Indians and a boon to many early explorers.       Economic status.--As the red-backed mice occupy mainly woodland and thickets they are of no great economic importance in the grainfields or meadows, but wherever they come in contact with orchards [p.90] and shrubbery, if present in great numbers, they are capable of doing considerable mischief, for trees and bushes girdled by them under the snow are usually killed or seriously injured. Their chief enemies are the small owls and hawks, weasels, skunks, and badgers, and these afford the principal protection we have from their depredations. Microtus pennsylvanicus pennsylvanicus (Ord) Eastern Meadow Mouse (Pl. 14) Mus pennsylvanicus Ord, Guthrie's Geogr., 2d Amer. ed., vol. 2, p. 292, 1815. (Reprint by S. N. Rhoads, 1894).       Type locality.--Near Philadelphia, Pa.       General characters.--Size rather large for a meadow mouse; ears, tail, and legs, short; body, heavy and compact; fur, long and soft in winter, thin and harsh in summer. Colors, dark brown or blackish above, slightly paler and more grayish below. Average measurements of adults: Total length, 171 millimeters; tail, 46; hind foot, 21.2. An adult female from Grafton measured 162, 34, and 19, respectively, and weighed 43.6 grams.       Distribution and habitat.--From a wide range over the northeastern United States the abundant meadow mice, pennsylvanicus barely reach into eastern North Dakota along the upper Red River Valley, and even here they are becoming slightly smaller than typical, in a very gradual gradation toward the little drummondi, which continues to the northwest. To this race are referred the Red River Valley specimens from Fairmount, Blackmer, Hankinson, Lidgerwood, Wahpeton, Fargo, Larimore, Grafton, and Drayton. Here as in most of the range of the species, they inhabit mainly the marshes, but are occasionally also found on the uplands under any tall grass or dense vegetation.       General habits.--As their build and color suggests, meadow mice are ground dwellers and spend most of their lives under the shadowy cover of dense vegetation. They burrow in the ground, which is often perforated with their little round tunnels, while over the surface they make well-defined roads or runways from one burrow to another or from their nests and burrows to feeding grounds, but always under the protecting cover of grass or other plants. They are partial to moist ground and prefer rough meadows where moisture is abundant and where water often stands over part of the surface. They are good swimmers and seem as much at home in water as on land, swimming from side to side of little streams or ponds and diving and swimming under water when necessary. Their runways often lead through wet places, but dry banks or hillocks are sought for their nest cavities. In summer they frequent the meadows and low moist ground, but in winter they leave their low underground burrows and push out under the snow of the uplands, extending their tunnels along the surface of the ground and building warm grass nests on the surface wherever they find an abundant food supply. In this way they often range over uplands, fields, and orchards in great numbers; and when the snow goes off in spring, leaving their network of winter roads, their grass piles, and their winter nests exposed, they burrow into the around again and do not all get back into the meadows until the dry weather of summer compels their return to the moist lowlands.       [p.91] Apparently they are about as much diurnal as nocturnal, although they appear to be most active in the early evening hours. Some are caught in traps during any part of the day or night, but they seem to fill up the collector's trap line more rapidly during the evening than at any other time. They do not become fat or hibernate and are active throughout the year without regard to weather.       At Hankinson, in July, 1912, they were found common in places where there was tall grass on the prairie, but more especially so in the meadows and among the tall tules on wet ground. After the hay was cut on the meadows they gathered under the haycocks in considerable numbers, and as these were loaded and hauled away the mice were forced out into the open stubble, where hawks or owls were constantly hunting them. As many of the extensive tule marshes in this region are never cut, they afford a safe harbor for the mice in which to multiply and from which to spread over the meadows and prairies. Similar conditions were found at Wahpeton, near Fargo and Grafton.       Breeding habits.--Meadow mice are very prolific and seem to have no well-defined breeding season. Females taken at any time of year from May to October are found to contain from 4 to 6 embryos and sometimes 8. Occasionally even in winter small young are found in nests or females are found with embryos. At times they increase very rapidly and remain abundant for a period, after which they become scarce, the variation presumably being correlated with protection from enemies and the abundance and quality of food. Their waves of abundance, which at times suggest migrating hordes, are undoubtedly due to favorable conditions for rapid reproduction.       Food habits.--During the summer the favorite food of meadow mice consists of tender vegetation, as the young shoots of grass, growing grain clover, alfalfa, and a great variety of plants. Acceptable food is always abundant. Sometimes the tender bases of grasses are chosen, and again the seed-laden tops are drawn down within reach by cutting the stems into inch-long sections. Seeds and grain are always favorite foods, when they are available late in summer and in fall, but in winter the mice thrive equally well on the frozen grass and roots that they get under the snow, or on the bark from bushes or trees which they gnaw off with their sharp cutting teeth, under cover of deep snow.       They are particularly fond of the bark of many fruit trees, especially apple, but will eat the bark of almost any tree or shrub that is not too thick and hard for them to gnaw into. Aspens and willows are found peeled and killed by them, but most of the larger woodland trees are protected by their harsh outer bark. In trapping them rolled oats are a favorite bait, but they will take any kind of grain or seeds and are specially fond of fresh meat, fat pork, or bacon. Their carnivorous propensities are seen in trapping, as they almost invariably eat their own kind or other mice found dead in traps.       Economic status.--Over a wide range of rich farming country these are the most abundant mice in meadows, fields, timber, and orchards, and their total destruction of forage, hay, crops, trees, and shrubs annually causes an enormous loss in agricultural products. Among these losses nothing is more exasperating than the destruction of a few choice fruit trees in an orchard, or some choice shrubbery in [p.92] the yard, during the period of deep snow in winter. Orchards are infrequent in North Dakota, so that the few choice, hardy fruit trees that can be raised are of special importance, and if the bark is gnawed from the base, even on one side, the trees are often weakened so as to be unable to resist the severe climate to which they are exposed.       In wild-grass meadows the hay is not of sufficient value for the mice to cause much loss, but in meadows of clover and timothy and fields of alfalfa their mischief is much more serious. They enter grainfields as soon as the growing crop is sufficiently high to afford protection, and cut the grain shoots for food; then when the grain is headed out, they cut off the base of the stems, drawing down the heads in order to reach the green and ripening grain. After harvest they congregate in the grain shocks and if these are left long in the field considerable grain is eaten or shelled out and destroyed. As either these meadow mice or closely related species with similar habits cover all of North Dakota, the total loss from them is by no means insignificant. The importance of placing every possible check on their increase is obvious.       That they can be successfully poisoned when necessary has been demonstrated, but the expense suggests this method as a last resource. The most practical method of controlling the abundance of such small rodents is by protecting their natural enemies, among which the owls and certain species of hawks are foremost. The little owls, during the dusk of evening and all night long, are watching for them and miss no opportunity to pounce upon an unwary mouse that exposes itself. The marsh hawk, or mouse hawk, as often called, sailing low over the meadow and prairie, with eyes intently fixed on the ground, drops suddenly into the grass and secures a mouse more often than it does any other prey. Many other hawks feed upon them extensively, as do also foxes, badgers, skunks, and weasels. But for these enemies the mice would overrun the farms with disastrous results. Microtus penusylvanicus drummondi (Audubon and Bachman) Drummond Meadow Mouse (Pl. 14) Arvicola drummondii Audubon and Bachman, Quadr. North Amer., vol. 3, p. 166 [1854].       Type locality.--Rocky Mountains, vicinity of Jasper House, Alberta, Canada.       General characters.--Similar to pennsylvanicus, but much smaller and slenderer, and slightly lighter, more yellowish brown in coloration. Average measurements of adults: Total length, 145 millimeters; tail, 39; hind foot, 17.8.       Distribution and habitat.--None of the North Dakota specimens of the little prairie or meadow mice are typical, but they are too small and slender-skulled to be called pennsylvanicus and can best be referred to drummondi, toward which they are slowly grading to the northwestward. The large series of specimens now available from many localities over the State show conclusively continuous range and complete intergradation between the two forms, and, drummondi is here placed as a subspecies of pennsylvanicus. To [p.93] it are referred specimens from Crosby, Lostwood, Kenmare, Towner, Turtle Mountains, Walhalla, Pembina, Sweetwater Lakes, Devils Lake, Stump Lake, Portland, Valley City, Lisbon, La Moure, Oakes, Ludden, Napoleon, and Dawson. This carries the range over the high glacial-prairie region between the Red and Missouri River Valleys to the southern boundary of the State and marks its southern limit from a wide range over western Canada to Alaska.       Over their part of the State Drummond meadow mice are very abundant and occupy the high open prairie, rich bottomlands, and grassy meadows. To some extent they are found in woods and thickets, but primarily they are dwellers in grasslands, wherever the low vegetation affords food and cover. In the Turtle Mountains the writer found them abundant in marshes, meadows, banks, and grassy fields, and even in damp woods, but they were most numerous in the meadows, where the ground was perforated with their runways. In spots nearly half the grass had been cut down for food, leaving the earth strewn with the fragments. At Walhalla, in the Pembina Hills, Williams reported them inhabiting woods, grainfields, and meadows. On Bird Island, in the arm of Devils Lake, where cormorants nest, the grass was full of runways. At Stump Lake the runways were found in the prairie grass apparently without regard to whether the ground was wet or dry. At Valley City Eastgate reported them common along the river valley, around the marshes, and in prairie meadows, and the writer caught them around some seepage springs high up on the side of the bluff. At Lisbon, Doctor Fisher caught one in a swampy thicket; and so on over the State they have been reported from a great variety of localities.       General habits.--If their habits differ at all from those of pennsylvanicus, it is only in a more ready adaptation to high open ground, such as the grassy prairies of their range afford. Their more open habitat may well account for this slightly paler coloration. Their little roadways are often conspicuous through the prairie grass, especially where the old grass has fallen down and made a protecting cover over the surface of the ground. Old winter nests are found scattered over the surface, but rarely are they occupied during the summer; the principal nests are then in underground cavities to which the burrows lead.       Occasionally an occupied nest is found in some old haycock or grain shock that has been left out over winter, and at Crosby a nest was found occupied by young in a heap of last-year's weeds by the roadside. The nest, as usual, was made of soft grass blades, built into a neat hollow ball, clean and fresh, and with a soft lining inside. It was placed in a slight depression in the ground, where it was well protected from rain and snow by the mass of matted vegetation overhead. The four small young inside, with their eyes just opened, were of a beautiful golden-brown color, quite different from the sooty, or slaty gray, young of pennsylvanicus of the same age.       Breeding habits.--In the latter part of June, 1912, in the Turtle Mountains, great numbers of these mice were caught in traps so that many were thrown away after series were selected for specimens. There were all sizes and ages, from little fellows just out of [p.94] the nest to nearly full-grown young of the year, indicating at least two litters of young of that season, while many of the females contained small or large embryos, usually 6, 7, or 8. The mammae are arranged in two posterior and two anterior pairs, so that 8 is probably the normal maximum number of young. Apparently breeding continues throughout the summer, if not throughout the year, and reproduction is so rapid that only through a host of enemies are their numbers kept down to a safe limit.       Food habits.--Grass and weed stems are found cut in little sections near the runways and on the feeding grounds of these mice and over considerable areas where much of the grass has been cut by them. The mice are fond not only of seeds but also of grain, and enter fields readily and help themselves to growing crops. Although never fat, they are always well fed and their stomach contents show various mixtures of green plant tissue, white pulpy root and bulb tissue, and the meal or dough of finely masticated seeds and grain.       Economic status.--Over an immense area of rich grain-producing land these mice swarm in greater or less abundance, varying with the seasons and with the abundance of their enemies. It would be almost safe to predict that at times, through disturbance of normal conditions in the agricultural development of the country, these mice will increase so as to do serious injury to crops. In such case it may become necessary to use artificial means of destroying them, but as with other small rodents, a wise protection of their enemies will generally produce sufficient check on their abundance. The destruction of weasels for fur and too great a reduction of skunks and badgers are likely to have a marked effect on the abundance of these mice while any wanton destruction of owls and mouse-feeding hawks would certainly be followed by an inordinate increase in the numbers of the rodents. Microtus pennsylvanicus wahema16 Bailey Bean Mouse; Hetunka (Pl. 11, fig. 2; Pl. 14) Hintunka of the Dakotas; Gipápuli of the Hidatsas; Sakch of the Arikaras; Bidábaho itáhu of the Hidatsas (all, Gilmore). Microtus pennsylvanicus wahema Bailey, Journ. Mamm., vol. 1, p. 72, 1920.       Type locality.--Glendive, Mont.       General characters.--A pale form of pennsylvanicus, slightly smaller and very much paler and grayer than the eastern meadow mouse, which it represents in the arid Badlands region. Upper parts buffy gray; sides clear gray, underparts and feet and lower surface of tail pale gray or buffy white. Measurements of type specimen: Total length, 178 millimeters; tail, 43; hind foot, 20. Weight of adult female, from Cannon Ball, 30.8 grams.       Distribution and habitat.--Bean mice occupy the Badlands section of the Missouri River Valley and range westward over southwestern North Dakota and eastern Montana. There are specimens from near the mouth of the Cannonball River, Bismarck, Mandan, Fort Clark, 10 miles south of Williston on the west side of the river, Oakdale, [p.95] Glen Ullin, and Sentinel Butte. This indicates a continuous range over the Badlands and sagebrush semiarid section of the State. In places the mice are found in marshy bottoms, but more often in the long grass of draws and on grassy benches of the ridges and buttes. Near the White House Ranch, about 12 miles south of Williston, a fine typical specimen was caught in 1913, on a grassy bench near the top of the Badlands border of the valley. At Fort Clark Jewett found others on high grassy slopes back of the valley bottom, and at Mandan on the high ridges wherever the grass was sufficiently dense to hide the animals and their runways. At Oakdale he found them about a small marshy place near a spring, where they were occupying the tall grass of a limited area. At Glen Ullin he found them common in the tall grass on moist ground along Curlew Creek, where their fresh runways were abundant. At Sentinel Butte he took specimens high up on the grassy slopes of the large butte south of town and others in the grass of a small slough near the station. Near Cannon Ball, Sheldon took specimens on the flats near the mouth of the Cannonball River and also on the high buttes to the north. In June, 1916, the writer collected them on the river flats near the mouth of the river and saw abundant signs in grassy places over the prairie and fields; and on October 30, 1919, took two of the mice at their nest and bean cache on the flats near the mouth of the river.       General habits.--In habits these mice differ from pennsylvanicus and drummondi only as their more arid habitat places them more in the open, sparsely covered, and grayer soil of this semiarid region, where they are evidently more exposed to light and to the numerous enemies overhead. The light-colored soils and minerals and general gray tone of sagebrush and prairie plants is evidenced in the color and, to some extent, in the habits of these little animals. They are less uniformly distributed over the area than are species in more fertile regions and in places they seem almost colonial, so locally are they gathered in the most favorable spots. In summer they were not easily caught in traps, as they seemed not to care for any bait that was offered them, and the few specimens taken merely ran through the traps set in their little runways under weeds and grass.       There has long been a question of whether these could be the bean-storing mice of the Indians of the Upper Missouri River, mentioned by Lewis and Clark and other early explorers as laying up such ample stores of wild beans, bulbs, and tubers, for a winter's supply of food that they formed one of the important sources of food supply for both Indians and whites. To decide this question many specimens of these, as well as of the other species of mice living along the Missouri Valley, were collected in localities where the Indians said the mouse stores were especially abundant. Some of the Indians and white men, who were familiar with the mouse stores, picked out the present species as the one which they had seen running away from the beans, but others were just as positive that the storers were the red-backed mice, white-footed mice, harvest mice, grasshopper mice, and pocket mice, while some thought the deposits were made by pocket gophers, ground squirrels, or chipmunks. Even the weasel was accused of storing these winter supplies. [p.96] The stores were frequently described and all seemed to agree as to their contents.       With pockets filled with underground beans of Falcata comosa (maka ta omnicha) and long tubers of wild artichoke, Helianthus tuberosa (pangi), and the little white tender roots of wild morning glory, the writer was able to question the Indians intelligently about the stores and the way they were found and gathered and cooked. Although the mouse bean seemed to be the principal part of the stores that were sought by the Indians, the artichokes and morning glory were said to be usually found with them, and one Indian insisted that the tipsin, Psoralea esculenta, was also sometimes found in the caches. One man insists that when driven away from their stores the mice often climb and take refuge in trees.       In describing the cache the Indians say that the mouse burrows enter the ground from several sides and the cavity where the food is stored often holds a peck or a pailful of beans and tubers. One Indian, who makes a special business of gathering these beans in the autumn, positively asserted that he could find enough in a day to fill a 2-bushel sack. The method of finding the stores is by noting either the burrows and runways centering at a certain point, or the tracks of the mice in the fresh snow leading to and from them. With a sharp stick the ground is probed, the cavities are soon discovered, and the beans removed. The fresh and wholesome vegetables were at one time an important adjunct to the meat diet of these hunting Indians, but at the present time their fields of vegetables and grain furnish an ample variety of food and the mouse stores are sought only by a few. The Indians claimed that it would be impossible to find the stores until late in October or early in November.       In October, 1919, six years later, the writer returned to the mouth of the Cannonball River in the hope of being able to settle the question of identity, and on next to the last day of the month succeeded in finding his first cache of beans and capturing the mouse with them. The night before he had trampled down the soft snow and in the morning found several fresh mouse holes made during the night entering different sides of a mass of snow and leaves. Digging in one of these holes with the left hand the writer saw a mouse soon pop out on the other side, only to be caught in the right hand, and placed in a glove, and carried home alive. The cavity was then carefully dug out and examined. A warm nest of grass and soft plant fibers was found about 6 inches below the surface in a cavity where an old stump had decayed. In another cavity near the nest was a small collection of the mouse beans or ground peanuts, with artichokes and a few roots of the wild morning glory. As the season had been very dry and both mice and beans were scarce, the cache was meager, but the cavity, which would have held several quarts or a peck, showed the old skins and remains of the previous year's collections. The store would doubtless have been added to until the ground froze so hard that no more beans could be dug. Though there may be other mice which store these beans, this meadow mouse is the first one actually caught at its cache and identified.       The Indians describe the cache as easily recognized by the little roads leading up to it from all sides, and tell how the mice drag [p.97] home loads of the beans on leaves. They have many legends and stories relating to these mice and their stores, which have been well translated by Doctors Beede and Gilmore, stories telling of the respect and reverence of the Indians for their little helpers, the mice people, of the payment in corn or other food for the beans taken, of the punishment of the hard-hearted woman who took all of the beans and left no exchange in food, and of the threat to fight any white man who attempted to capture or injure the mice or take their stores.       History.--The use of these ground beans evidently dates far back. Mr. Will (1917, p. 66) in speaking of the mythical origin of the Hidatsas from a hole in the ground in the vicinity of Devils Lake, says: "At that time the people cultivated ground beans and wild potatoes, two crops that were not really cultivated at all but merely gathered."       Apparently the first white men to mention the beans were Lewis and Clark (1893, p. 161, 263), in 1804, on their visit to the "Ricaras" (Hidatsas), when among other presents of food they were given "a large rich bean which they take from the mice of the prairie, which discover and collect it." The next spring their "Bird Woman," Sacagawea, gathered these food stores of the mice, which must have lasted over winter.       In 1833 Maximilian (Wied, 1843, p. 26) includes this bean among the plants used by the Mandan Indians as food under the name "feverolles (Fabia minor equina), a fruit resembling the bean which is said to grow in the ground but which I did not see."       Again, Father De Smet (1905, p. 655), an early missionary to the Indians of the Upper Missouri, as he left Fort Union in 1851 wrote in his journal:       The earth pea and bean are also delicious and nourishing roots, found commonly in low and alluvial lands. The above-named roots form a considerable portion of the sustenance of these Indians during winter. They seek them in the places where the mice and other little animals, in particular the ground squirrel, have piled them in heaps.       In 1855 Lieut. G. K. Warren (1856, p. 78) wrote:       The groundnut, or Apios tuberosa, is very useful to the Indian. It grows very abundantly along the river bottoms, and is gathered in large quantities by a kind of wood-mouse for his winter store. The squaws make a business, during the months of October and November, of robbing these little animals, and I have often seen several bushels of the tubers in a single lodge. They are boiled with dried buffalo meat, and make a rich and palatable dish.       Thus a long and useful career has been shown for these little animals and we can well appreciate the feeling of regard for them still held by the older Indians. Now, however, that most of their range has become valuable grain land, their services are no longer needed and their inroads on grain, grass, and other crops are likely to prove as serious as those of other related species in agricultural areas. It is safe to say, however, that they will not be exterminated nor their numbers greatly reduced by the presence of the white man's civilization. The only danger is that under cover and stimulus of cultivated crops they may increase to such abundance as to become a menace, but if their natural enemies, owls, hawks, and weasels, are given a fair chance any overabundance will be effectively checked. [p.98] Microtus ochrogaster haydenii (Baird) Western Upland Mouse (Pl. 14) Arvicola (Pedomys) haydenii Baird, Mamm. North Amer., p. 543, 1857.       Type locality.--Fort Pierre, S. Dak.       General characters.--A medium-sized field mouse of the subgenus Pedomys, with short ears, legs, and tail, the tail about twice as long as the hind foot. Color dull gray with a cinnamon tone, only slightly paler below. Fur long and lax, giving a pepper-and-salt effect of light-tipped hairs over dark underfur. Measurements of adult female from type locality: Total length, 180 millimeters; tail, 47; hind foot, 22.       Distribution and habitat.--The pale western form of Microtus ochrogaster of the central prairie States occupies the semiarid Plains region from Kansas to Montana, and comes into North Dakota west of the Missouri River. There are specimens from Cannon Ball and Wade, and the writer saw runways and burrows near Stanton that undoubtedly belong to this subspecies. Unlike the meadow mice, they avoid low or wet ground and usually are found on the high, dry prairie in rather open situations. In many places they occupy little thickets of rose and wolfberry bushes, but their characteristic runways and burrows are often found on the open ground, fully exposed to view.       General habits.--At Cannon Ball, the upland mice were found to be common over the prairie and on the dry valley bottoms. In places they were living under a good cover of prairie grass, where their little roadways over the surface of the ground led to the burrows and some old surface nests that had evidently been used during the winter. In other situations they lived in the thin prairie grass, where their runways were easily followed. In some locations they were living near the edges of thickets, where it would have been an easy matter for them to gather the mouse beans had they been inclined to store them. Specimens were easily caught by setting traps across the runways, baited with rolled oats, or even set unbaited, as in running along their roads the mice would trip over the trigger and spring the traps. To a certain extent they seemed colonial in habits, but probably this is merely because in a good location the family increases until the place is well stocked before the members of the colony begin to scatter out. At times they become very numerous locally, but, generally, the open nature of their habitat exposes them to so many enemies that they do not last long.       Food habits.--The food of this mouse is largely green vegetation, including the stems and leaves of grass and a great variety of little plants that are found cut in sections in their runways. It also eats the flowers and seeds of many plants, is usually eager for rolled oats or other kinds of grain used as trap bait, and will often eat its own kind found dead in traps. Preference for high and dry ground brings it much in contact with cultivated fields, where it finds choice food in the green or ripening crops.       Breeding habits.--Females taken for specimens often contain four to six embryos and the mammae are arranged in two posterior and one anterior pairs. Apparently they breed many times during the season and are only a little less prolific than meadow mice.       [p.99] Economic status.--In North Dakota these mice have been so little observed that any injury to crops has escaped attention, but in other parts of their range, where farms and orchards have been of longer standing, they have been known to occasion serious losses by killing fruit trees and by destroying grain and grass in fields and meadows. Potentially they are dangerous occupants of any agricultural region and with unchecked abundance might become a serious pest. Microtus minor (Merriam) Little Upland Mouse (Pl. 14) Arvicola austerus minor Merriam, Amer. Nat., vol. 22, p. 600, 1888.       Type locality.--Bottineau, N. Dak.       General characters.--Smaller even than drummondi, with short ears, short tail, and coarse, lax fur. Color, coarse pepper-and-salt gray, produced by pale-buff tips of long hairs over black underfur; underparts but little paler. Adults measure in total length approximately 140 millimeters; tail, 33; hind foot, 17.       Distribution and habitat.--In a range extending from southern Minnesota to Edmonton, Alberta, the little upland mice cover approximately the eastern half of North Dakota. There are specimens from Bottineau, Kenmare, Starkweather, Goodall, Devils Lake, Stump Lake, Valley City, Sherbrooke, Oakes, Lidgerwood, Fairmount, Hankinson, and Blackmer. Over the prairie they are usually found on dry ridges or sandy soil, in which they delight to burrow. They seem to avoid low, damp ground and their habits as well as their fur mark them characteristic upland mice, a group quite apart from typical meadow mice.       General habits.--Apparently colonial in habits, the upland mice are usually found abundant in favorite spots and in no others for long distances. Often their burrows enter the ground in groups of half a dozen or more and are more or less connected below the surface. Some of these groups suggest a family colony, and others are more extensive and scattered along for a considerable distance in irregular formation. At Bottineau, in the summer of 1887, these mice were abundant over the dry prairie in small colonies, usually on mellow, somewhat sandy soil. At Kenmare, near the top of a high ridge or point of the prairie running out on the edge of Des Lacs Valley, their little runways and burrows were found numerous over the dry slope. The ground was covered with a network of fresh trails through the short prairie grass and there were three sets of burrows, in each of which 10 or 12 holes entered the ground within a radius of 2 or 3 feet. These seemed to be family or colony dens and several of the mice were caught around each group. Fresh earth was being thrown out on all sides and from each opening a trail led off to the feeding grounds or to other dens and burrows.       A number of traps were set and in one night about 20 of the mice were caught. Many were young of the year and of various sizes, but enough adults were obtained for a good series of specimens. Mouse traps were sunk in the ground across their runways and baited with rolled oats and ripe and green wheat, all of which were eagerly [p.100] accepted as bait. Near Blackmer, Sheldon and the writer found four distinct colonies in an alfalfa field and one on the prairie sod on the Clarey farm, not far from the station. Those in the alfalfa fields were the most extensive covering from 2 to 3 square rods of ground each and consisting of 20 to 50 burrows and innumerable trails. The ground was thickly perforated by the burrows and generally half the alfalfa had been killed over the range of the colony. Much was cut and eaten on the surface, but considerably more was killed from below, evidently by having the roots eaten off in winter. As pasturing kept the crop low, there was no trouble in finding the mice, observing their habits, and obtaining a good series of specimens. A pair of short-eared owls were nesting in the adjoining field, and served to keep the mice within bounds, but if the alfalfa had been allowed to grow to full height the mice could have increased without interference.       At Valley City the writer caught one on the high prairie under tumbleweeds, where a few of their old trails were found, though the mice seemed to be scarce. At Sherbrooke, Loring took six specimens in traps baited with meat and rolled oats, set along their beaten runways through the weeds. On the Peterson farm, 10 miles West of Portland, he took two in the daytime in runway traps, and at Portland caught others in similar manner. At Towner, Kellogg secured a specimen in an upland meadow, and at Goodall he found a colony on the sandy flats close to the river bank.       On the short-grass prairies these mice are exposed to view from overhead, but on the dark prairie soil in their little roadways they are protectively colored, and their habit of keeping close to their burrows and darting quickly from one burrow to another seems to be their main protection against numerous enemies.       Breeding habits.--As in other members of this subgenus (Pedomys) the mammae of the females are arranged in two pairs inguinal and one pair pectoral. Females have been taken containing four and eight embryos, but the normal maximum number of young is probably not more than six. Evidently the young are born at irregular times throughout the season, but the length of the breeding season and the number of litters have not been definitely determined.       Food habits.--Grass stems and many prairie plants are found cut in sections along the runways of these mice and near the burrows, while in numerous places little prairie bulbs, as those of the wild onion and the blazingstar, have been dug up and eaten. In the alfalfa field at Blackmer both the green leaves and tender stems of alfalfa plants were eaten, and underground the roots had been extensively gnawed. The fondness of the mice for rolled oats, grain, and meat, used for baiting traps, indicates a wide range of food.       Economic status.--From the nature of their habitat in fields and on the uplands these mice are likely to prove as injurious to crops as any of the other species, and under favorable conditions of food and cover, such as are found in extensive alfalfa fields, they might well become a serious pest. Where exposed to their natural enemies, however, they are not likely to do more than merely swell the total loss chargeable to small rodents. [p.101] Microtus pallidus (Merriam) Pale Mouse (Pl. 14) Arvicola (Chilotus) pallidus Merriam, Amer. Nat., vol. 22, p. 704, 1888.       Type locality.--Fort Buford, N. Dak.       General characters.--Recognized by its small size, compact form, and very short tail, which is but little longer than its hind foot; fine soft fur of a light buffy gray color over the upper parts and creamy white below; ears and nose conspicuously yellow. The type, an adult female, measures in total length, 121 millimeters; tail, 20; hind foot, 18.       Distribution and habitat.--The rare little Pale mouse (subgenus Lagurus) is known from only a few scattered localities from western North Dakota, Montana, and Alberta. Two localities only are represented by specimens from North Dakota--Fort Buford and Glen Ullin. In September, 1887, the writer first found them on a Badlands butte, 2 miles east of Fort Buford, where they seemed quite common in the half-barren ground just below the top on the north slope. The only reason that could be suggested for their choice of location on the north sides of the hills was that the twilight, their favorite time for activity, was longer on the shady slopes. The vegetation seemed to be about the same all the way around the summits of the hills and at best was only scantily represented. At Glen Ullin, Osgood collected three specimens in September, 1901. This is on the high dry prairie, but no report was made of the exact location at which they were caught.       Apparently this is one of the rare species which occurs only at widely scattered localities, and may be nearing extinction. No mammal has been more sought for by collectors in the region where it occurs, and with so little success. In 1915, and 1919, the writer again visited the butte where the type was collected, but could find no trace of burrows or runways on this or any of the neighboring buttes.       General habits.--Apparently all that is known of the habits of the pale mouse is the little gleaned from the few specimens collected at the type locality, where they were living in a colony along the shady slope of the butte. The little round burrows entered the side hill at frequent intervals along the well-worn runways leading around the slope. In places the runways passed over grassy ground, where they were well packed by the little feet constantly using them. In other places they passed over naked soil and were only detected by the smoothly worn surface. At that time no suitable traps for catching such little animals were available and the mice seemed strangely suspicious of the clumsy box traps. Only four specimens were taken, although the colony was quite extensive and probably contained a dozen or more individuals. Rolled oats and traps now used had not been invented in those days and the mice did not care for any of the baits offered them.       Food habits.--A large part of the food of these mice seemed at that time to consist of the flowers of the little silver sage (Artemisia frigida) and the blazing star (Liatris graminifolia), and the stems and pieces left from these plants were scattered along the runways and about the entrances of the burrows; heads and seeds of winterfat (Eurotia lanata) also were eaten. Many grasses and other plants [p.102] had been cut, apparently for food. A partly eaten bulb of the blazingstar was found near a runway, where it had been dug up. Corn and oats, and the seeds of cactus and other plants and also bread, cake, and cheese, were placed around the burrows, but it all remained untouched. None of the specimens taken showed any signs of becoming fat and it is improbable that they hibernate, even in this northern latitude.       As a young naturalist, for the first time away from his home fauna and among new and strange animals where the thrill of discovery was not infrequent, the writer recognized this mouse as something strange and probably new, and it was with the keenest pleasure that a communication was received from Doctor Merriam, stating that he, also, had been unable to identify it as a member of any described species. Fiber zibethicus cinnamominus Hollister Great Plains Muskrat Zih-zirukka of the Hidatsas (Maximilian); Sinkpé of the Dakotas (Gilmore); Shantshuke of the Mandans (Will); Citakh of the Arikaras (Gilmore). Fiber zibethicus cinnamominus Hollister, Proc. Biol. Soc. Washington, vol. 23, p. 125, 1910.       Type locality.--Wakeeney, Trego County, Kans.       General characters.--Size medium for a muskrat, not so large as the more northern nor so small as the southern species. Fur, dense and soft; ears, short; tail, long, nearly naked, flattened and rudderlike; hind feet, large and webbed; musk glands, well developed. Measurements of adults: Total length, about 496 millimeters; tail, 240; hind foot, 73 or 74. Weight, about 2 or 3 pounds.       Distribution and habitat.--The bright-colored Plains form of the muskrat, as defined by Hollister (1911), covers the central Plains region from Oklahoma to Manitoba, including all of North Dakota. There are specimens in the National Museum collections from Fairmount, Oakes, Lisbon, Valley City, Grafton, Fish Lake, Wood Lake, Towner, Elbowoods, Grinnell, Buford, and Dawson. It is safe to say there are muskrats in every suitable slough and lake, marsh and stream in North Dakota, in numbers ranging from a few individuals in the smaller ponds to thousands in some of the extensive marsh and lake areas. While it is impossible to obtain a reliable estimate of their numbers, or of the numbers taken for fur each year, they certainly are the most abundant and valuable fur-bearing animals of the State, as they are of the whole United States.       General habits.--In the lakes and extensive tule marshes near Hankinson, the writer found muskrats abundant in 1912, and there were many old muskrat houses along the shores and numerous bank burrows leading up from under water along the margins of the lakes. As usual, much trapping kept the animals down to a small part of the number that the lakes could profitably carry. They were common at Wahpeton in the river and sloughs, and at Fargo, where they live in the Red River banks, and at Stump Lake and Devils Lake in the tule-bordered sloughs over the prairie; they were scarce, however, in the brackish and alkaline water of the lakes.       [p.103] In the Turtle Mountains they were found in the lakes and sloughs with which this hilly and forested region abounds, and were especially numerous in the beautiful clear water of Gravel Lake, where a novel use was found for them near the fish hatchery, and where trapping was not allowed. The lake had been stocked with trout, perch, and bass, and the muskrats were protected and allowed to build their houses along the shores in order to keep breathing holes open to prevent the ice from closing up so completely as to smother the fish. Both fish and muskrats were thriving and multiplying rapidly and the system seemed to be working remarkably well. The muskrats were comparatively tame and it was a pleasure to watch them swimming, diving and feeding out in the water. They would often lie stretched at full length on the surface, eating roots which they held in their hands above the water. Others would sit in round furry balls on the ends of logs or on the edges of their half-submerged houses, munching the green plant stems or tender roots and bulbs, which they had procured from the bottom of the lake or from the grassy banks.       Just across the ridge from this lake, at the fish hatchery, other muskrats were doing considerable mischief in the fish-breeding pond by tunneling through the banks and letting out the water. The half dozen animals that were doing this mischief could have been caught with very little trouble and the banks protected, but the feeling seemed to be growing that the muskrats were a great nuisance, fostered probably by the lake full of valuable fur just over the ridge. Wherever the lake banks are high enough for burrows the muskrats live mainly in bank dens, but in the wide tule-bordered lakes and sloughs, where the water is so deep that the winter ice will not reach the bottom, they build large winter houses out in the water. Thus the abundance of muskrat houses in one situation is no indication of a greater number of the animals than in adjoining lakes where none are seen.       Around the Sweetwater Lakes muskrats are generally abundant in spite of much trapping, as the marshes are very extensive and the conditions ideal or them. About Castleton, Loring reported them wherever any water could be found. Sheldon reported them common along the lake shore near Dawson, and Kellogg reported them in Wood Lake, and especially abundant in Muskrat Lake, Sullys Lake, along Shell Creek, in Turtle Creek, and at many points along the Missouri River and adjoining sloughs and streams, from Grinnell to Bismarck. In 1915 Sheldon found them abundant across the southern part of the State, from Fairmount and Oakes to Napoleon and Cannon Ball and the Badlands farther west. Along the Little Missouri River Valley, in 1913, Jewett found comparatively few in the creeks and sloughs.       Although leading mainly aquatic lives, muskrats are perfectly at home on dry land, and often when their stream or pond dries up will strike out across the prairie to find a new home. Their peculiar tracks, showing the large hind feet and small front feet, with a narrow line where the tail drags, are often seen in dusty roads and in trails between sloughs. They are sturdy fighters, and if cornered will combat anything that comes along, but if taken when young and tamed they make gentle and interesting pets.       [p.104] They are great builders and work industriously to make the walls of their houses thick and firm before cold weather comes. It is often said that the larger the houses and thicker the walls, the colder the winter is going to be, but even muskrats sometimes make mistakes in their forecasts. As long as open water is available underneath, cold weather has no terrors for the animals in their winter homes; but the thicker and icier the walls of their houses, the safer they are from all enemies except man and his traps. Usually two or more openings lead from the nest chamber in the center of the house down into the water, and as long as these openings are kept clear the animals are free to come and go as far as water extends under the ice. Air holes through the ice are kept open in the vicinity of the houses or bank burrows and apparently the animals obtain plenty of oxygen from these and the bubbles lying under the ice, or from the air carried in their dense coats of waterproof fur.       Breeding habits.--The young are usually brought forth in bank burrows, apparently sometime in May, and in June they are first seen swimming about as little quarter-grown muskrats. Apparently six to eight to a litter are the usual numbers; some credit them with two or three litters during a season. Half-grown young occasionally caught in fall are generally supposed to be from second litters, but they may be merely the first litters of late young of the previous year. Apparently the young of the year do not attain full size and weight the first fall, but by the following spring it is difficult to distinguish between most of the yearling and older animals. They are very prolific, have few enemies except man, and will quickly and abundantly restock suitable grounds where they are given protection. Like other rodents, they show no signs of mating for more than a brief temporary period. The whole care of the family devolves upon the mother, for after the young are born the male has no further place in the family life. Apparently the males fight for supremacy, as occasionally one is caught with its skin cut full of slits, evidently by the incisor teeth of an opponent.       Food habits.--In summer the muskrats feed on the tender shoots and stems of numerous grasses, tules, cattails, and water plants along the shores, on roots and bulbs, which they take from the bottoms and banks, and to some extent on mussels and other animal food. In July, 1893, Doctor Fisher reported that in the Sheyenne River, near Lisbon, where they were common, he found piles of mussel shells at various places along the banks where the muskrats were in the habit of feeding. In Apple Creek, near Bismarck, they were found in the same ponds with the beavers and several were caught in beaver traps. Many little heaps of freshwater mussel shells were found along the banks where muskrats had been feeding, and Doctor Bell actually saw a muskrat bring up and cut open one of these shells. In many places where they are in the habit of feeding, the accumulation of grass and plant stems builds up little mounds or platforms on which they sit while eating their meals. They are said to be very fond of carrots and parsnips, which are often used for trap bait.       Economic status.--Under certain circumstances muskrats do serious damage, as when they get into irrigation ditches, artificial ponds with dams or raised banks, or in roadways through marshes. [p.105] Their burrows will quickly destroy ditch banks and dams. In 1916, they had nearly ruined a graded road running west from Devils Lake for about 2 miles through a large marsh. In about 50 places they had burrowed into the sides of the grade and in many cases clear across under the road, causing the surface to break through into the soft mud below. They had also made hollow dens under the road into which passing horses had broken through. The road was graded only about 2 feet above the surface of the marsh, but even if it had been raised much higher the burrows would have been a constant menace. It would have taken at least $100 to repair this road at the time it was examined, and repairs would have been useless as long as the muskrats were left there. This seemed a serious situation, but it could have been controlled with no expense, merely by allowing and encouraging thorough trapping, in this particular marsh, where every muskrat could have been caught at a profit. In very few places in North Dakota, however, is there any complaint of mischief done by muskrats, while the annual income from their fur reaches many thousands of dollars, well distributed among the residents of the State.       Fur farming with the muskrat in its native marshes has been successfully carried on in many sections of the country, as fully described by Lantz (1910, 1917), in Farmers' Bulletins 396 (issued in 1910) and 869 (issued in 1917) of the United States Department of Agriculture. Family CASTORIDAE: Beavers Castor canadensis canadensis Kuhl Canada Beaver Ah-mik' of the Ojibways; Ah-misk' of the Crees (Seton). Castor canadensis Kuhl, Beitr. Zool., p. 64, 1820.       Type locality.--Hudson Bay.       General characters.--Beavers, largest of all our rodents (sometimes weighing 60 pounds or more), are heavy-bodied, strong, powerful animals, with large, webbed, hind feet; broad, flattened, naked, scaly tails; dense, fine underfur, and long coarse outer hair of a dark chestnut-brown color; and short ears and huge chisel-like incisor teeth well adapted for cutting wood. In fresh fall fur they are dark, rich chestnut-brown in color, which fades to a somewhat lighter brown before the spring molt. An adult female from Mouse River, near Towner, collected by Remington Kellogg, July 30, 1915, measured: Total length, 1,150 millimeters; tail, 400; hind foot, 195; and weighed 53 pounds; it is unusually dark brown, but otherwise seems to be typical of the northern beaver. The young of all ages agree closely with the adults in coloration.       Distribution and habitat.--Although there is very little material from which to judge, it seems safe to assume that all beavers in the Hudson Bay drainage, including the Mouse River and Red River Valleys, are of the typical form (canadensis), and very different from those of the Missouri River drainage (missouriensis). Formerly beavers were abundant in all the streams and many of the lakes of North Dakota, but today they are restricted to a few scattered localities where colonies have received sufficient protection to enable them to regain a foothold since the days of overtrapping.       [p.106] In 1800 Alexander Henry (1897, pp. 117, 143, 145, 154, 175, 177, 408) said that beaver houses were numerous along Red and Goose Rivers, near Grand Forks, and more numerous than elsewhere on the upper Sheyenne River. Two of his trappers, from a trip up the Red River, brought in 60 beaver skins on November 17, two others, 60 skins from the Hair Hills on Park River, and the next spring two men brought in 30 skins from the vicinity of Grand Forks. Two other trappers on Park River took 25 skins in two days, and so for six years Henry's bands of Indian trappers scoured the branches of Red River and trapped in the Pembina Hills and Turtle Mountains for the furs that were poured out through the waterways eastward, to be shipped to England. As a result of this systematic destruction, Henry, in 1806, further records that where formerly plentiful beavers were becoming very scarce. Following is a partial record of beaver skins taken by his parties from the Red River Valley during the years 1801-1808: In 1801, Reed River, 832; Park River, 643. For the winter of 1802, Grand Forks, 410; Hair Hills, 200. In 1803, Turtle River, 337; Hair Hills, 30; Pembina River, 550. In 1804 Grand Forks, 856; Hair Hills, 182; Park River, 147; Pembina River, 211. In 1805, Hair Hills, 121; Park River, 160; Pembina River, 829. In 1806, Grand Forks, 342; Pembina River, 776. In 1807, Pembina River, 565. In 1808, Grand Forks, 150; Hair Hills, 53; Pembina River, 339. Although these localities merely indicate the camps from which his men worked out in all directions, the records give a good idea of the fur harvest in its prime, and also of the rapidity with which the beaver was reduced to numbers that no longer paid the trappers for their time and effort. As early as 1848 David Thompson (1916, p. 249) wrote that the beaver had become very scarce in the Red River Valley near the mouth of Park River.       The former abundance of beavers in these streams shows conditions favorable to their habits and in many instances marks the places where they could now be maintained in considerable numbers as an attractive and profitable form of livestock.       In 1887 no trace was found of beavers along the Red River Valley nor were any colonies heard of on the way down the valley to Pembina.       In 1893 Doctor Fisher noted a few in the Sheyenne River, near Lisbon, but in 1912 Eastgate reported them as extinct there 16 years before, although he found old cuttings and dams. It is possible that there are still a few beavers along the banks of the Red River, but no one has been able to get any trace of them in recent times.       In the Turtle Mountains, in 1912, only one colony of beavers was found, and that was carefully protected by the owner of the property, who was anxious to have them multiply as rapidly as possible. All through these mountains, however, old traces of the former abundance of beavers was found, while dams closing the outlets of ponds, marshes, and lakes showed where they had been responsible for retaining the richness of the land and spreading it out instead of having it washed away by the spring floods. The best of the meadows in this region are all old beaver ponds that have been filled up with silt. There are also numerous lakes where the beavers used to live in the banks, as shown by old burrows, and where to-day [p.107] the interesting animals might live in considerable numbers without doing harm. If adequate protection could be afforded they would soon increase and restock this whole region, once a trappers' paradise.       One morning before daylight in 1915, Kellogg counted 15 beavers about 8 miles north of Towner, where they had built a big brush house on the bank of the Mouse River. At this place the water was about 15 feet deep, but a dam had been built part way across the river to increase the depth. In the early days beavers had been very numerous along this stream, and old settlers told Kellogg that its course had often been changed by their dams. At the time of Kellogg's visit there was another colony 4 miles farther up the river.       At Kenmare, in 1913, there were complaints of beavers doing great damage to property on Carl Swensen's place on Mouse River, about 20 miles northeast of there. On the bank of the river just below the McKinney Bridge, three or four beaver houses and the places where timber had been cut along the borders of the stream were examined. Apparently there were 20 or 30 beavers occupying the half mile of stream examined, and they were said to be equally numerous below there and above to the Canadian line. C. E. Booth, a taxidermist, reported later that beavers were common in the Mouse River near Minot, and that there were eight dams across the stream just above Burlington. There is considerable small timber scattered along the course of this river and in a great prairie region even small timber is highly prized. At Mr. Swensen's place the beavers had built winter houses along the banks of the stream by piling up the sticks which they had cut, often a wagonload or more, in heap 5 or 6 feet high, above their rooms and nest chambers in the bank and plastering them over with mud. During the visit the houses were not used to any extent, as the beavers were living mainly in bank burrows, but before winter all of these houses would be repaired and put in good condition to protect the dens from freezing during the winter.       The beavers were not cutting many trees at that time, but seemed to be feeding mainly on the green vegetation along the river banks and on willow stems and roots. Mr. Swensen showed the bank where they had cut trees the previous fall and the writer counted about 40 stumps of small ash, 2 to 6 inches in diameter, about 20 boxelders, and a dozen elm stumps of the same general size. The largest ash which they had cut was about 10 inches in diameter and another about that size had been killed by being girdled. Seven boxelders 8 or 10 inches in diameter, entirely or partly girdled, were either dead or dying. Most of these trees were in a narrow strip about 40 rods long on the bank of the river opposite the ranch house. Mr. Swensen estimated that the beavers had killed 200 or 300 trees for him and more for some of his neighbors. A few of these trees were large enough for fence posts but the greater number were too small to be of any value except for shade and protection from the cold winter winds. The Swensens were much interested in the beavers and their work, but strongly objected to feeding so many of them on their choice trees.       It would seem a simple matter for State officials or game wardens to be detailed in such cases to control the abundance of beavers [p.108] where they were doing mischief, and to capture alive and remove any surplus to other parts of the State where they would be of value in stocking suitable waters. Castor canadensis missouriensis Bailey Missouri River Beaver Capa of the Dakotas (Gilmore); Midapa of the Hidatsas (Matthews); Wahrapa of the Mandans (Will); Citukh of the Arikaras (Gilmore); Zhaba of the Omahas (Gilmore). Castor canadensis missouriensis Bailey, Journ. Mamm., vol. 1, p. 32, 1919.       Type locality.--Apple Creek, 7 miles east of Bismarck, N. Dak.       General characters.--Slightly smaller than canadensis; colors, paler and duller brown; back, bright hazel brown; sides, duller brown; and underparts, smoky gray. Young, same color as adults. Measurements of type (about 18 months old and not full grown): Total length, 900 millimeters; tail, 270; hind foot, 170. Weight estimated at 35 or 40 pounds.       Distribution, habitat, and general habits.--Apparently the light-brown subspecies of beaver occupies the Missouri River drainage, at least from Nebraska north and west to Montana. In North Dakota it still occupies the Missouri River and many of its tributary streams. A number of skulls in the National Museum were collected by Lieutenant Warren, along the Upper Missouri, probably in North Dakota. There is also a skull from old Fort Stevenson, part of a skull from the Little Missouri, and a broken skull from Medora, besides the type and one immature specimen from Apple Creek, but much more and better material is needed before a satisfactory diagnosis of the form can be given or the details of its distribution fully made known.       In 1804-5 Lewis and Clark (1893, p. 194) found beavers abundant along the Missouri River throughout the North Dakota section of their journey, even in close proximity to long-established Indian settlements. At the Mandan village they speak of two French trappers coming into camp with 20 beavers that they had caught near there. Trappers were then just beginning to find this river a rich field for their fur harvest.       In 1833, Maximilian reported 25,000 beaver skins bought during the year at Fort Union (now Buford). Among his many observations along the Missouri River he (Wied, 1839-1841, Bd. 2, pp. 54, 55, 1841) wrote on November 5, from just above the mouth of the Little Missouri:       *   *   *   we lay to for the night on the south bank where the forest was completely laid waste by the beavers. They had felled a number of large trees, chips of which were scattered about on the ground. Most of the trees were half gnawed through, broken down, or dead, and in this manner a bare place was formed in the forest. Not far off we saw in the river a beaver den, or as the American sometimes call it a beaver lodge, to which there was a very well trodden and smooth path, which we availed ourselves of to go to and from our boat. Nature appears to have peculiarly adapted these remarkable animals to the large thickets of poplar and willow of the interior of North America, where the whites on their first arrival found them in countless numbers and soon hastened to sacrifice these harmless creatures to their love of gain.       [p.109] Ten years later Audubon (1897, p. 76) at Fort Union, wrote in his journal about the beavers "once so plentiful, but now very scarce. It takes about 70 beaver skins to make a pack of 100 pounds; in a good market this pack is worth $500, and in fortunate seasons a trapper sometimes made the large sum of $4,000."       Already the quest for rich fur harvests had swept beyond this region, but fortunately, where the beavers had the protection of the deep water and high banks of the larger rivers, it had not quite exterminated them. With characteristic tenacity they still cling to their old haunts or merely scatter out to establish new colonies in tributary streams, but the love of gain has not entirely disappeared from the land and these new colonies are rarely able to keep their coats on their backs for any great length of time.       At Buford, in 1910, Anthony reported a few in the Missouri and Yellowstone Rivers, apparently about as many as were found there in 1887. In 1913, Doctor Bell and the writer found many signs of their presence along the Missouri River near Williston and about 18 miles to the southeast, on the west side, found a dam where a few were living in a creek.       At Fort Clark, in 1913, Jewett reported beavers common along the Missouri River and one colony located on a small creek about a mile south of the town. The willows had been cut for houses and dams, and some were also scattered along the river shores, where they had been used for food. In the Killdeer Mountains, Jewett reported beavers common in all suitable creeks in the region; there was a small colony on Jims Creek 3 miles south of Oakdale, and another colony on Charlie Bob Creek on the east slope of the mountains. Their dams and houses were well protected by the owners of the land. At Medora he saw several fresh cuttings along the banks of the Little Missouri and beavers were reported to him as common in places above there.       From Medora down the river to Quinion, Jewett found beavers in several localities along the Little Missouri and on Magpie Creek. In the river at the mouth of Magpie Creek a few had been caught the previous fall, and on Magpie Creek, near Quinion, a beaver dam of aspen, willow, and chokecherry bushes had been built across the creek. The dam was about 8 feet high and 20 feet long between the creek banks and had formed a pond from 5 to 8 feet deep and half a mile long. The colony had been there for several years and was well protected by the ranchers.       In the deep ponds of the Little Missouri River, near what was then the North Dakota National Forest, about 25 miles south of Medora, Doctor Bell and the writer found where beavers had been cutting cottonwood trees and building houses on the banks. Just below the camp they had a large house on the bank of the river made mainly from the branches of several cottonwoods which they had cut down near by. The largest tree cut was about 10 inches in diameter, and others still larger had been cut half way through or the bark eaten from one side. Only cottonwoods and willows had been taken, and as these were abundant and of little value the beavers were not doing serious damage in this section. Along Deep Creek, on the national forest, where there was no timber and only willows and chokecherry bushes, the beavers had made numerous dams and [p.110] some good-sized ponds. On Bullion Creek, south of Sentinel Butte, a colony had built a dam of willow and chokecherry bushes and maintained a large pond, which kept the creek flowing throughout the year where it had formerly gone dry in summer.       In Apple Creek, just east of Bismarck, in 1914, beavers were reported to have destroyed $1,000 worth of timber. To get at the facts, a trip was made to Bismarck and their work all along the stream carefully examined. The beavers were not numerous at that time, but the half dozen old dams that had been cut and broken out showed that the animals had previously been there in much greater numbers. In a distance of about 6 miles, the writer estimated 15 to 20 beavers, including two families of young, but there had probably been twice as many the previous year. In all about 75 stumps of small trees that had been cut down were found mainly elm and ash, but 1 oak and 1 boxelder had been cut and 1 cottonwood had been girdled and killed. Most of these were not 5 inches in diameter, and they would average about 2 inches. Most of the wood, probably 8 or 4 cords, had been hauled to the ranches. The majority of the bushes cut were diamond willows and chokecherry, which are used both for food and for building dams and houses. The actual value of all other timber cut along this creek would not exceed $20. In a prairie country where timber is scarce every little tree has a value for shade and protection as well as for the relief it gives to the monotony of open country, but the beavers also add life and interest to the country, and in addition have a cash value usually greater than that of a few small trees.       Other complaints were made of damage done at the same time by beavers along Sweet Briar Creek, just west of Mandan, but when Doctor Bell went to investigate he found a few small trees cut for food and building purposes, but very few beavers were left. Most of them had been caught and the trappers and farmers were clamoring for permission to catch the rest. In other places, however, the beavers are given adequate protection by residents who are interested in having them on their farms.       In 1915 Kellogg found traces of beavers along the Missouri River and Antelope Creek near Goodall, and reported a fair-sized colony near Expansion, a large colony below Independence, a freshly built dam across Deep Water Creek below Shell Village, and another colony on a lagoon at Armstrong. On the Knife River he found two beaver houses, and near Sather, in Burleigh County, a few houses and some fresh beaver work. Near Sawyer he reported one small colony, and another in a bend of the river near Painted Woods, while from there to Bismarck he found the houses at almost every bend of the river where there were groves of diamond willow and small cottonwoods.       At Cannon Ball, in 1916, the residents said that there were still some beavers along the Missouri River and also along the Cannonball River, its side streams, and old sloughs and channels. At Parkin, about 8 miles above the mouth of the Cannonball, there were a number of beavers in the deep parts of the river, with dens in the high banks. They were cutting willows and cottonwood brush along the shores. One evening as it was getting almost dark a big old fellow came up on the tank of the river and, climbing out [p.111] on a stump, reached up and quickly cut off a cottonwood branch about 6 feet long, dragged it to the water, and then swam down the river, towing it after him, eating it under cover of a steep bank below. Farther up the Cannonball, at Wade, in 1913, W. B. Bell reported a considerable number of beavers in both branches of the river and photographed a dam on the south fork just above the juncture of the two streams. They had done some damage here by cutting down cottonwood trees up to 18 inches in diameter. One ranchman, Mr. Twigg, estimated that 300 trees had been cut on his ranch. On October 23, 1910, O. N. Dvergsten wrote to the Biological Survey from still farther up the Cannonball, near Stowers, inquiring what he could do with beavers that were destroying his little trees along the creek. A few of the animals had come there the previous year, built their winter home, and kept on building and cutting his trees in spite of his efforts to discourage them. Their house had been torn out, but they had rebuilt it and insisted on remaining.       In 1919, after two years of open season on beavers, many of the colonies had disappeared or had been sadly reduced in numbers. A few traces of their work were found along the Missouri River at Sanish and Bismarck, and there were said to be a few beavers still in Apple Creek and Burnt Creek. Near the mouth of the Cannonball River they were very scarce, although they had been fairly common up to 1916.       In a deep loop of the Heart River near Mandan late in October there was still a small colony. Here they had cut down a few scrubby cottonwoods and a large number of willows along the bank and had stacked the green branches and sections of trunks in deep water for winter food. The top of this mass of green wood and brush reached to the surface and was securely held together by several inches of ice. There was one beaver house on the bank and many burrows and dens in the steep banks, which were about 15 feet above the water. Several vent holes opened out from 50 to 80 feet back from the river and warm air was steaming out of them on cold mornings. These beavers were well located for an experimental beaver farm or for a wonderful city-park colony at the edge of Mandan.       Beaver houses.--Large beaver houses are often built out in ponds where the surrounding water is 6 or 8 feet deep, with walls of matted sticks and mud rising 4 or 5 feet above the surface of the water, enclosing safe and comfortable living rooms. The nest chamber, usually just above the water level, has its only doorway leading down through deep water under the house to the pond outside.       Bank houses are generally smaller but equally well-built structures of sticks and logs well plastered with mud. They are commonly built on low banks to protect the dens from outside enemies. In high banks the burrows generally enter water and come up well back in the banks into nest chambers that are unmarked by any external building material.       Beaver dams.--The dams are generally built of brush, sticks, limbs, and trunks of trees that have been cut into sections of a convenient size to be carried, dragged, or floated to the desired spot, pushed into place, and covered with mud from above the dam. Well-built dams [p.112] show a steep lower face of crisscross sticks and a sloping upper face of mud or firmly packed earth. They offer a wonderful resistance to floods and the wear of time, and many old beaver dams may be found to-day that have not been used for a century or more.       On small streams beaver dams are usually of a simple type, built across the channel so as to raise the water above them to sufficient depth for good ponds. A depth of 6 or 8 feet is required to protect the houses, dens and bank burrows, and to insure a winter swimming pool under the ice. Much deeper water is preferred and the beaver will usually leave and hunt for better quarters if a depth of a least 6 feet can not be maintained.       Large and rapid streams are rarely dammed, except by large colonies of beavers left undisturbed for a long term of years. Some of the old dams show great skill and industry, but the best results seem to be due to persistent efforts in the face of many failures, rather than to the high order of mentality usually attributed to the beavers.       Food habits.--The food of beavers varies with the season. In summer it is mainly grass and other green vegetation. At Apple Creek, in August and September, the beavers were feeding on coarse water grasses and sedges along the shores of the creek. The grass blades were scattered over the surface of the ponds and lodged against the dams and in many places the banks were well cropped. All of this was waste material that could not be cut for hay or grazed by stock. The stomachs of the beavers collected contained large quantities of green pulp, apparently of this material, with the addition of a little of the bark and twigs and roots of willow, and some other plants that could not be identified. The trees and bushes cut at that time had been used mainly for building material rather than for food.       In fall beavers begin to cut down bushes and trees to be stored under water for winter food. Sometimes tons of green brush mixed with limbs and sections of tree trunks are sunk to the bottom in deep, still water, where under the ice it keeps fresh and green and is available all winter. The bark is eaten off the larger stems and the twigs and buds are browsed where they lie or are carried into the houses to be enjoyed at leisure.       That willows are the principal winter food, as well as the favorite building material, is evident from the food stores, the remains of meals and structure of houses and dams. Cottonwoods and aspens are preferred for food where available. The hardwoods--elm, ash, boxelder, birch, and even oaks--are sometimes cut for building material, but rarely for food. On Apple Creek, some elm and ash, one small bur oak about 2 inches in diameter, a small boxelder, a thornapple bush, and a few hop vines had been cut, all of them evidently for building material, as they showed no indications of having been eaten. Boxelder and bullberry bushes were abundant along the stream, but were rarely touched by the beavers. One thornapple bush full of red fruit had been cut and placed on the dam. The rootlets of willows, which grow in dense masses under water along the banks, are also a choice food for both summer and winter, and in deep water, where beavers are scarce and timid, they get much of their food from these tender roots without exposing themselves on the surface.       [p.113] Breeding habits.--Usually four to six young are raised at a time and it is doubtful if more than one litter is raised in a year. Increase is therefore not rapid and the young do not get their full growth for several years.       Beaver parks.--Near Jamestown, in 1914, W. B. Bell visited a beaver colony that had been protected for a number of years and allowed to build a good dam across the Dakota River. The animals were comparatively tame and could be watched at their work on the dam or on the banks, or swimming about in their pond during the daytime, and were a source of much interest and pride to the community.       The beginning of a valuable and educational zoological park was here developing spontaneously without any expense or trouble beyond the mere protection of the animals. Unfortunately, a grainfield extended down to one edge of the beaver pond and naturally the beavers accepted the grain as a part of their food supply. Even after the grain was cut they pulled the bundles out of the shocks and carried them to the water for food and building material. The loss of grain, though scarcely appreciable, naturally irritated the owner and roused a sympathetic feeling for him and against the beavers, until, as a result, the colony was destroyed.       If a woven-wire fence had been placed along the river bank and woven wire wrapped around the bases of a few trees, the beavers might have remained as a harmless and delightful interest for the public. No more interesting or simple and inexpensive zoological park can be maintained by any community than a good beaver colony.       Beaver farming.--In many sections of North Dakota conditions are excellent for raising beavers under control and partial or complete domestication in small lakes or ponds or in fenced sections of creeks and small rivers on owned or leased land. If beavers were included in the list of fur-bearing animals permitted to be raised under special license (North Dakota, 1923, pp. 317-318), a valuable industry might be added to the State, and much waste and unprofitable land made to yield returns to the owners. The selection of stock for beaver farming is of great importance, since the dark, richly colored animals, as found in the Hudson Bay drainage or, still darker, from northern Michigan and Wisconsin, have far greater fur value than the light-brown beavers of the Missouri drainage, and as far as possible should be used for breeding stock.       Beaver meat.--If properly prepared, beaver meat is good and wholesome. In the adults it is dark, tender, rich, and of good flavor. There is usually a layer of fat over the surface next to the skin, and the tail is always of a soft, fatty tissue which if well cooked is especially delicious. Among the trappers beaver tail has always been considered a luxury equal to buffalo tongue.       Lewis and Clark (1893, p. 276), in their journal of April 17, 1805, say, "Around us are great quantities of game, such as herds of buffalo, elk, antelopes, some deer and wolves, and the tracks of bears.   *   *   *   We obtained three beavers, the flesh of which is more relished by the men than any other food which we have." This is almost the unanimous testimony among trappers.       In skinning the beaver care must be taken not to get on the flesh a trace of musk from the large gland located under the skin of the [p.114] belly. The beaver should be hung up by the head and skinned without touching the meat with the hands. It is impossible to handle the skin without getting the hands scented by this very clinging, although not unpleasant odor."17 Family ERETHIZONTIDAE: Porcupines Erethizon epixanthum epixanthum Brandt Yellow-haired Porcupine; Rocky Mountain Porcupine Pahi of the Mandans (Will); Pahi of the Dakotas (Gilmore); Apadin of the Hidatsas (Matthews); Suunu of the Arikaras (Gilmore). Erethizon epixanthus Brandt, Mém. Acad. Imp. Sci. St. Pétersbourg, t. 3 (ser. 6), pt. 2 (Sci. Nat.), p. 390, 1835.       Type locality.--Northwestern America.       General characters.--Heavy, wide-bodied, short-necked, short-legged animals with short, stout tails, long curved claws, flat, naked soles and an armor of quills; upper parts densely covered with very keen barbed quills, embedded in black fur and partly concealed by long yellow-tipped outer hairs; underparts mainly without quills. An adult male from Montana measures in total length 875 millimeters; tail, 314; hind foot, 112. Weight, approximately 20 to 30 pounds.       Distribution and habitat.--From a wide range in the Rocky Mountain region the yellow-haired porcupines reach their eastern limit, so far as known, in North Dakota. They are fairly common in the Missouri Valley and westward in the State, but east of the river valley they are rare and scattered. A specimen collected by U. S. Ebner in the Turtle Mountains in 1914, and now in the collection of the North Dakota Agricultural College, at Fargo, marks the easternmost authentic locality for the species. Near Warwick, just south of Devils Lake, in 1915, Kellogg reported a yellow-haired porcupine killed by two boys the previous year; at Towner on the Mouse River, one killed by Almond Larson in 1905, and another found dead by Clyde Coss in 1911. In 1913 there were reports of porcupines having been killed near Kenmare and Minot, but there was no real clue to the form represented. It was undoubtedly, however, the yellow-haired. At Buford and all the way down the Missouri River through the State porcupines have been reported common from 1910 to 1915 by Anthony, Kellogg, and Jewett, and apparently their numbers have not changed much since the days of Lewis and Clark, Maximilian, and Audubon. In 1913, Doctor Bell reported them fairly common at Wade, on the Cannonball River, where two had been recently killed near Mr. Wade's ranch and a skull of one obtained for a specimen. In 1919 they were found common about Sanish, in the brushy gulches on both sides of the Missouri River.       General habits.--Although well safeguarded by their own spiny armament, the porcupines often seek additional safety in the Badlands and brushy stream bottoms, in the protection of little caves and hollows in the banks or the dense, thorny cover of buffaloberry thickets. Near Williston, the writer found their characteristic oval [p.115] pellets in the little caves of the Badlands, which seemed to be their favorite dens. Often, however, the animals are met in the open and at night they follow trails and roads for long distances, as shown by their double rows of oval, flatfooted, denticulate tracks in the dust.       Although their ordinary gait is not much faster than that of the turtle, they are patient and persistent travelers and sometimes their tracks may be followed for miles. When met with, the porcupine usually attempts to escape, but if crowded, bristles up, erects its quills, and stands at bay awaiting attack. The quills are pointed out at all angles and as the enemy approaches within reach, fierce blows of the heavily armed and muscular tail are struck sideways or upward and the barbed quills thus driven into anything within reach.       The common belief that the quills are thrown to a considerable distance has no foundation in fact, although some are occasionally scattered on the ground if the animal is roughly handled. Porcupines evidently realize that their lower surface is unprotected, as any effort to turn them over is frantically resisted, and when threatened the quickness with which they will wheel and strike is surprising in animals so clumsily built.       Their long, very hooked claws enable them to climb trees readily, and the animals are as much at home on the trunks or branches as on the ground. They also climb about in the bushes and seem to enjoy the tops of the very spiny buffaloberry bushes, which probably give them a feeling of added protection along their own lines of defense. The tops of these bushes are often eaten bare of bark, leaves, and berries and left in a very mutilated condition. The writer has never seen any evidence that porcupines dig burrows, but quite probably they dig out or enlarge some of the cavities in which they dwell.       Breeding habits.--The mating season is said to be in October and one or sometimes two young are born early in spring. At birth the young are unusually large and well developed; their eyes are open and they are provided with a good set of fur, quills, and incisor teeth. They follow the mother until weaned an apparently before they are half grown each one is able to shift for itself and to begin its solitary life. With this slow rate of reproduction the species would soon disappear but for its armored protection.       Food habits.--During the summer porcupines feed on a great variety of green vegetation, accepting apparently almost anything that comes in their way and stuffing their enormous stomachs to the limit of their capacity. At Stanton, Kellogg found one feeding in an alfalfa field with its stomach well filled with alfalfa; he said they were reported to do some damage in the grainfields between Washburn and Bismarck. Jewett reported them as fairly common in the brushy gulches near Sentinel Butte, where they had gnawed the bark from many of the chokecherry bushes. Near Sanish they had eaten the bark and twigs from buffaloberry, black haw, chokecherry, and rose bushes. In 1913, on the former Dakota National Forest, about 25 miles south of Medora, they were found fairly common in the Badlands gulches and on the forested ridges. Many of the yellow pines had been gnawed more or less extensively by [p.116] them. On some of the forested ridges about half of the small trees showed peeled spots from which the bark had been eaten and some had been completely girdled and killed. Most of the old trees showed some scars from earlier gnawings.       Still farther south, along the Little Missouri, near Marmarth, where yellow pines grow irregularly over the buttes, the writer found fully a fourth of the young trees damaged through having the bark gnawed from them by porcupines. In some cases the bark had been eaten from the tops and branches; in others the trunks had been girdled, so that many of the trees were either ruined or killed outright. The old pines showed a long struggle with their enemy, the bushy tops and gnarled forms being largely due to the girdling of tops or branches at different times during their lives. Here, as in many other parts of the country, the bark of yellow pines seems to form the favorite food of the porcupines, at least during the winter season. The rough outer coating of bark is rejected and the tender inner growth eaten as it is scraped clean from the wood of the trunk. Apparently the bark from a space the size of a hat is required for a square meal. Any tree that happens to be conveniently near the porcupine's den is sure to suffer and may be stripped of all of its bark from top to bottom.       Economic status.--Although most wild carnivores have become sufficiently accustomed to porcupines either to let them alone or, by taking advantage of their unprotected bellies, to kill and eat them with little harm to themselves, many dogs gain their first knowledge of the species by sad experience. The greatest complaint of the settlers against the porcupines comes from this injury to their dogs, for if a dog attacks one recklessly as it would any other animal it may be seriously or fatally injured by the quills. The destruction of crops by porcupines is usually of small consequence, but their destruction of many species of pines and other conifers often causes great loss to the forests within their range. It is not improbable that they are largely responsible for the scarcity of timber in the Badlands region; were it not for them a fair stand of pines might have spread over this rough country. If reforestation of these areas is attempted, it will be necessary to first eliminate the porcupines, as where they are common no young trees can reach a well-developed maturity. Erethizon dorsatum dorsatum (Linnaeus) Blackhaired Porcupine; Canada Porcupine [Hystrix] dorsata Linnaeus, Syst. Nat., ed. 10, t. 1, p. 57, 1758.       Type locality.--Eastern Canada.       General characters.--Color, black and white instead of black and yellow; upper parts covered with white, black-tipped quills, mixed with black fur and obscured by long black, white-tipped hairs. Usually not so large as the yellow-haired porcupine from farther west. An adult male from Minnesota measures in total length 740 millimeters; tail, 195; hind foot, 115; an adult female, 735, 195, and 100 respectively. Weight of female, 16 pounds; of male, probably 20 pounds.       Distribution and habitat.--The black-haired porcupines occupy the timbered Canadian Zone area of the northeastern United States and Canada west to the Great Plains, where they probably meet the range of the yellow-haired porcupines. They are common in northern Minnesota, but for North Dakota there seem to be only two or three [p.117] probable records and these unsubstantiated by specimens. M. A. Brannon writes that while at the university, at Grand Forks, he had a small black-haired porcupine for a pet, but it met with an untimely death and was not preserved for a specimen. It was given to him and was said to have come from the Red River Valley, near Pembina. H. V. Williams reports a porcupine of the small dark-colored type, almost black, killed at Hamilton, in Pembina County, on July 31, 1916. The description fits this species, which on geographic grounds ought to be found there rather than the large yellow-haired species which has been taken no farther east than the Turtle Mountains; but the young of both species are blackish, so that identification depends in part on age. The boys at the Indian school near Wahpeton killed a porcupine on the river bank near town in 1914 and described it but no specific characters could be gathered from the description. Others will probably be found along the Red River Valley, and it is hoped that a specimen may be preserved to determine the species positively. Family ZAPODIDAE: Jumping Mice Zapus hudsonius campestris Preble Prairie Jumping Mouse (Pl. 13) Zapus hudsonius campestris Preble, North Amer. Fauna No. 15, p. 20, 1899.       Type locality.--Bear Lodge Mountains, Wyo.       General characters.--A medium-sized mouse with very long, slender hind legs and feet and small front feet; tail, very slender and longer than head and body; ears, small. Upper parts, bright buffy yellow along sides, darker along the back; underparts, pure white. Average measurements: Total length, 222 millimeters; tail, 135; hind foot, 30.5.       Distribution and habitat.--As its name implies, the prairie jumping mouse is a plains species covering practically the whole of North Dakota and the surrounding prairie country. There are specimens in the National Museum from Wahpeton, Fairmount, Blackmer, Hankinson, Ellendale, Fargo, Harwood, Lisbon, Pembina, Necho, Turtle Mountains, Devils Lake, Fort Totten, Valley City, La Moure, Ludden, Cannon Ball, Fort Clark, Grinnell, and Buford. Specimens have also been recorded in the Field Museum from Bottineau, Minot, and Jamestown. Although generally distributed over the State these jumping mice are found mainly in thickets, weed patches, meadows, or tall grass areas rather than on the high open prairie, where the grass is short and the cover scant.       General habits.--Under the protecting cover of bushes, weeds, and tall grass, these timid little jumping mice make their summer homes on the surface of the ground and their winter homes in burrows deep underground. They do not make roads or runways, but go through the grass with long leaps or little hops and occasional with a slow creeping motion on all fours. When startled, they go bounding away with long jumps, suggesting frogs, and usually make two or three leaps before stopping to see if they are pursued. Generally, if the last leap is well noted, one can creep up cautiously and catch the mouse by clapping the hand over it. When caught in this way the mice rarely offer to bite or make much effort to escape, [p.118] but may be handled and examined freely if held gently in the hollow of the two hands. Evidently they are not entirely nocturnal, as they are often startled from their feeding grounds in the daytime, but more often they are disturbed in their nests, from which they bound away when one steps close to them in the grass.       The summer nests are placed on the surface of the ground, well concealed under grass or other vegetation; they are neat little balls of fine grass with a tiny opening at one side and a soft lining in the central chamber. When the grain is cut and the hay mowed the nests are disturbed and the jumping mice go to live in the shocks of grain and cocks of hay where they are discovered when the hay and grain are being loaded on wagons. As they bound from under cover to the open ground they are somewhat dazed by the light and can usually be watched for some time as they sit blinking in the open or progress by long leaps through the air.       Hibernation.--Unlike most of the mice, these little fellows become excessively fat in autumn and with the first frosty nights retire to their warm underground nests and curl up for a long winter's sleep. The thin oily fat is deposited in a layer of white fatty tissue over the whole inside of the skin as well as over much of the surface of the body and fills the inside cavities until the animal is about twice its natural size and weight. This fat supplies sufficient nutriment and fuel for the long winter sleep and probably carries the animal through the early springtime of breeding activities when food is scarce.       Breeding habits.--The five or six young are brought forth in the nests usually in May or June, and are barely full grown by the time their winter sleep is to begin. In this latitude it is doubtful whether more than one litter of young is raised in a summer.       Food habits.--In the examination of a great many stomachs of these jumping mice, nothing has been found but the fine white pulp of carefully shelled, well-masticated seeds. Generally these are from grasses, although grain and a variety of other plant seeds are eaten. The mice are fond of rolled oats used for trap bait, and are easily caught in a variety of traps set where they are in the habit of running. To obtain the seeds of grass, on which they mainly subsist, they cut off the tall stems as high up as they can reach, draw them down and cut them off again, and repeat this until the seed-laden tops can be taken. Little heaps of grass stems cut in sections about 3 inches long are found through the meadows where the jumping mice live and are unmistakable evidence of their presence, being always much longer than the grass cuttings of meadow mice and other short-legged species. Apparently these rodents do not store up food, but live a very carefree life in the midst of abundance while the summer lasts.       Economic status.--Generally the jumping mice are not sufficiently abundant to do any great harm to the yield of grass and grain, but in places over limited areas in the meadows their cuttings might aggregate 2 or 3 per cent of the grass. They cut down and eat or destroy a small quantity of grain along the edges of some fields, but on the whole are far less numerous and injurious than the meadow mice. Still, they help to swell the total of the tax levied by rodents on farm products and only fail through lack of numbers to form one [p.119] of the serious rodent pests. Their natural enemies are the same as those of the other nocturnal mice, chief of which are owls, weasels, badgers, and skunks, through the good offices of which their numbers are kept within bounds. Family HETEROMYIDAE: Pocket Mice, Kangaroo Rats Perognathus fasciatus fasciatus Wied Maximilian Pocket Mouse Apapsá of the Hidatsas, Zhizhina of the Dakotas (Gilmore). Perognathus fasciatus Wied, Nova Acta Acad. Caes. Leop.-Carol. Nat. Cur., t. 19, pt. 1, p. 369, 1839.       Type locality.--Upper Missouri River near its junction with the Yellowstone, northwestern North Dakota.       General characters.--Considerably smaller than the white-footed mice, with small ears, slender tails, and conspicuous fur-lined pockets on the cheeks, opening externally and not connected with the mouth; hair, short and glossy; upper parts, olive gray; underparts, pure white, bordered by a buffy line along each side. Average measurements: Total length, 135 millimeters; tail, 65; hind foot, 17.       Distribution and habitat.--Maximilian pocket mice are scattered over a large part of western North Dakota and adjacent areas of the semiarid plains. There are specimens from Buford, Crosby, Minot, Dunseith, Fort Clark, Cannon Ball, Wade, Dawson, Oakes, Bowdon, and the Little Missouri River north of Medora, but the range is probably more extensive and continuous than these scattered localities indicate. They are animals of the open prairie, where they live in tiny burrows in the barest situations or on the short-grass plains, for, unlike most mice, they avoid the cover of vegetation.       General habits.--In 1833, Maximilian, Prince of Wied (1839, p. 373), found this anomalous little pocket mouse near Fort Union, at the junction of the Yellowstone and Missouri Rivers, and in 1839 first described it as a new genus and species of rodent. For more than 50 years no more specimens were obtained, and the name was confused under another species and not put in its proper relationship until 1889, when Doctor Merriam (1889, pp. 2, 4, 11) published his revision of the North American pocket mice.       In 1887 the writer visited Fort Buford and collected a small series of specimens that served to verify Maximilian's excellent description of the genus and species. At that time he was unacquainted with animals of their general habits and had only common steel traps, old-fashioned choke traps, and little tin box traps, and knew of no more tempting bait than cheese, bread, cake, or meat, none of which they would touch, so that although instructed to look out for them and get specimens, he then failed to catch any in his traps. Their characteristic little burrows were common and their tiny tracks recognized as undoubtedly belonging to the species, were found every morning about the traps, although no attention was paid to the bait. Other methods were evidently necessary to obtain specimens.       During the dusk of evening as the writer walked over the prairie, sometimes one of these little mice would dart over the ground near [p.120] him, and by dropping his gun and making a quick spring he could catch it in his hands. All but one of those seen were caught in this way, but in that one case his fingers came down on the mouse's tail and the rest of him escaped. This kind of hunting, though exciting at times, nearly ruined his shotgun, which invariably was dropped on the ground at the first move of the mouse, although he resolved each time to lay it down carefully when the next one was seen. The half dozen specimens obtained served to reestablish the identity of the species but they did not add much to knowledge of its general habits. Only in later years was it learned that with modern traps baited with rolled oats the mice could be caught in abundance wherever they occurred; since then naturalists have been able to learn more of their habits.       Their little burrows are usually found in groups of two or three on some dry, open spot, often at the edge of a cactus or sunflower patch, or close to sagebrush, and are easily recognized by their very small size. A little fresh earth is occasionally found thrown from some of the burrows, but in most cases the entrances are unmarked and inconspicuous. In 1910, Anthony collected specimens at Fort Buford and reported burrows found sparsely on the prairies and hilltops, usually in the sides of banks or slight elevations. One specimen was taken in an open space in the sagebrush near the river. At Crosby, in 1913, the writer caught one under some old Russian thistle at the edge of a flax field. At Minot, on October 12, 1919, he tracked one over a soft snow from a strawstack to a hole under a furrow, and digging back about 2 feet found it in a cup-shaped nest of soft plant fibers, captured it alive, and kept it for several months for study. At one edge of the nest cavity it had a small collection of seeds, mainly pigeon grass and Russian thistle seeds, which proved its favorite food in captivity. At Fort Clark, Jewett found these mice fairly common about the wheatfields and high dry prairies back from the river, where they were readily taken in traps baited with rolled oats and set near the small burrows. At Cannon Ball, Sheldon found them common in the grainfields on the sandy places and along the flats of the river. At Wade, farther up the Cannonball River, W. B. Bell collected a specimen for the agricultural college museum. In 1892, Theodore Roosevelt caught a specimen on the Little Missouri River, 40 miles north of Medora, which he contributed to the Biological Survey collection.       Small, inconspicuous, and mainly nocturnal in habits these little pocket mice, even where most abundant, generally escape the notice of all but naturalists or keen observers. It has remained for a local naturalist, Stuart Criddle (1915), of Treesbank, Manitoba, to study their habits in a careful and thorough manner. In excavating their winter burrows he learned more of them than was ever known before. He found their burrows penetrating as far as 6 feet below the ground, where the winter nests and stores were well protected from frost. Apparently enough seeds were provided to carry them through the winter. Their winter stores consist mainly of seeds of noxious weeds, and Criddle's conclusions were that the mice are mainly beneficial in their foods habits. Such careful studies of mammal habits by local naturalists are of inestimable value for the better understanding of native species.       [p.121] Hibernation.--These mice are rarely if ever found with sufficient accumulation of fat to suggest hibernation, but Criddle says that when exposed to moderately cold atmosphere they become very sluggish and he thinks that they spend much of the winter in sleep. The writer has found them active up to October 6 in Montana, and to October 12 in North Dakota, and they have been taken even later farther south. A captive specimen was active well into the winter, but in a warm house. The question of hibernation is not yet fully settled.       Breeding habits.--A female caught on May 13 contained six embryos, and Criddle reports one containing four. The mammae are arranged in two pairs of inguinal and one pair of pectoral on four distinct mammary glands. It seems probable, therefore, that six is the normal maximum number of young. There are no data to indicate more than one litter in a year.       Food habits.--In 1887 these pocket mice were found feeding mainly on the seeds of pigweed and knot grass, and at Crosby in 1913, they were living under the Russian thistle, which apparently furnished them food as well as cover. At Buford, Anthony reported their pockets filled with small angular seeds, which were probably of knot grass, and at Fort Clark, Jewett reported several caught at the edges of wheatfields with grains of wheat in their pockets. Others have been taken with their pockets filled with grass seeds, lambsquarters, red root, and tumbleweed, and Criddle found in their homes and pockets seeds of grass, blue-eyed grass, bug seed, wild buckwheat, and puccoon. He also discovered grasshopper eggs stored in their tunnels and found many places where these had been dug out of the ground. One of the mice that he kept in captivity preferred meal worms to seeds.       Economic status.--From the evidence gathered it seems that these mice are very slightly, if at all, harmful, while in many ways they are decidedly beneficial; but there still remains much to be learned of their habits and tastes. Perognathus flavescens perniger Osgood Dusky Pocket Mouse (Pl. 15) Perognathus flavescens perniger Osgood, Proc. Biol. Soc. Washington, vol. 17, p. 127, 1904.       Type locality.--Vermilion, S. Dak.       General characters.--About the size of fasciatus, but more intensely colored, with the rich buff on the upper parts much obscured by a wash of bright black, and the underparts chiefly rich, buffy ochraceous. Measurements of type: Total length, 140 millimeters; tail, 68; hind foot, 17. Weight of live adult, 10 grams.       Distribution and habitat.--The silky little dusty pocket mice come into southeastern North Dakota from their range over the prairie country of western Minnesota, eastern South Dakota, and the adjoining corners of Nebraska and Iowa. There are specimens from Hankinson, Blackmer, Lidgerwood, Napoleon, and Finley, and the writer picked up a dead one in the town of Parkin, about 10 miles above the mouth of the Cannonball River, too mangled to be saved for a specimen. The range of the form somewhat overlaps that of [p.122] fasciatus, from which it is entirely distinct. Apparently this is merely a dark-colored prairie form of the paler flavescens of the semiarid Plains region farther south and west. Sandy prairie soil is their favorite habitat and their little burrows are usually found in the mellow and often barren soil among prairie grasses.       General habits.--In the old lakeshore sand dunes, a little south of Hankinson, these little animals were found fairly abundant. On the crests of many of the low ridges or mounds that bad once been dunes, from one to a half dozen of their burrows or groups of burrows were found. There was generally a little mound of sand like a small gopher hill, and, whether freshly made or old, the entrances to the burrows were invariably closed. Often two or three other burrows, just large enough for the end of the finger, would be found near the closed one, but these were inconspicuous and rarely showed any trace of dirt having been thrown out. Traps baited with rolled oats and set at any of these holes, or across a long trail made by scraping the foot in the sand, readily caught the mice, for while they do not make trails of their own, they invariably follow any clear road through the grass. Often in the morning their tiny tracks were found over the open, drifting sand. A few specimens were taken in traps set near the tracks which led from the burrows to the feeding grounds. Although more easily located on the open sand, the mice were much less numerous there than in the scattered vegetation, which afforded some cover.       At Blackmer two were caught in a sandy field where boys said mice were often turned out by the plow. At Lidgerwood, Sheldon found them common in the grainfields and a series of specimens was taken in traps set in the fields. At Parkin the writer found many of their characteristic burrows and tracks in sandy ground near the edge of the town that had just sprung up on the prairie and picked up a dead mouse in the grassy street.       Breeding habits.--Three females collected at Elk River, Minn., on July 30 and August 12, 1912, contained four embryos each. The mammae are arranged in two pairs of inguinal and one pair of pectoral, which for the present constitutes our total knowledge of the breeding habits of this species.       Food habits.--At Hankinson the traps were baited with a mixture of rolled and whole oats, but as ants carried away most of the rolled oats during the day the whole grain was usually the only attraction for the mice. Most of the specimens caught had in their pockets some of the whole oats, from which they had removed the hulls, and some had also the seeds of needle grass (Stipa spartea), while the pockets of others were entirely filled with these long grass seeds, hulled and neatly packed in little bundles. There were occasionally also a few seeds of bindweeds and small wild beans. Of course, their food varies with the time of year, and at this season, July 19 to 27, the abundant Stipa seeds were just falling to the ground and the mice were busy gathering their harvest. At Lidgerwood, Sheldon found that the pockets of all of those caught in wheatfields contained weed seeds, with the exception of one that had gathered up a few particles of cracked corn; some of them also had included a few kernels of oats from his trap bait. The one picked up at Parkin had its cheek pouches full of little bean seeds, probably of Astragalus, [p.123] which was common there. In Minnesota the writer found where the mice had been feeding extensively on the seeds of sand bur, one of the most troublesome of weed grasses.       In the underground winter storerooms of these mice there were seeds of two species of pigeon grass, a few other grasses, and wild buckwheat. In captivity their favorite food has proved to be first of all the pigeon-grass seeds from their own winter stores, then Russian thistle seed, millet, wild sunflower, hemp, and rolled oats. They nibble a little cabbage, turnip, cooked potato, lettuce, celery, or green grass, but apparently more for the moisture than for food, as in a dry, furnace-heated house, they become very thirsty and eagerly suck water from saturated cotton or drink from a small dish.       None of the animals caught showed any indications of becoming fat as in hibernating species, but it is evident that they store up much food in the form of small seeds.       Economic status.--Too scattered in their distribution to be of any serious consequence one way or another, the habits of these little mice appear to be mainly harmless. Their consumption of weed seeds probably counterbalances any possible mischief in grainfields. Perognathus hispidus paradoxus Merriam Kansas Pocket Mouse (Pl. 12) Perognathus paradotus Merriam, North Amer. Fauna No. 1, p. 24, 1889.       Type locality.--Banner, Trego County, Kans.       General characters.--Size, large; tail, long; ears, small; pelage, glossy but coarse and hispid; external cheek pouches, conspicuous; upper parts, yellowish-brown with scattered black hairs over the back; sides, clear yellowish; underparts, white. Average measurements of adults. Total length, 222 millimeters; tail, 108; hind foot, 26.       Distribution and habitat.--These large pocket mice have an extensive range from Mexico over the Lower and Upper Sonoran semiarid plains region to western South Dakota, and one specimen has been taken in North Dakota. This was collected by Doctor Bell, in August, 1913, at Wade, on the Cannonball River. The specimen is now in the agricultural college collection, at Fargo, and is of special interest as marking the northern limit of the known range of this species. It is a large female, measuring in total length 220 millimeters, tail 114 and hind foot 27, and was caught in a trap set on a sandy area on the Wade ranch. At this locality the species represents an element of the Upper Sonoran Zone, which is sparingly shown also by the native vegetation.       General habits.-Over their wide range these mice are generally scattered and not abundant, but occasionally got into the collector's traps set in open country. They live in burrows of their own construction, which are often recognizable by their size and form, as they are larger than ordinary mice burrows and not so large as those of kangaroo rats. Moreover, they often go straight down into the ground like a smooth auger hole, around the entrance of which no trace of earth is found. Always at some place not far away, however, is a burrow at which considerable earth has been thrown [p.124] out, showing that the unmarked openings are those that have been opened from below. Sometimes the burrow at which the earth is thrown out is closed at the entrance; at other times it is left open.       The underground habits of the pocket mice are little known, except that specimens taken often have their cheek pouches well filled with seeds, grain, or trap bait, which they are carrying home, evidently to be stored for food. They are very fond of rolled oats and are readily caught in traps baited with them. A great variety of seeds is eaten, but the mice do not usually show any signs of accumulating fat for winter, and it is doubtful whether they regularly hibernate. Over most of their range farther south they may be caught at any time during the winter. Perodipus montanus richardsoni (Allen) Richardson Kangaroo Rat (Pl. 11, fig. 3) Dipodops richardsoni Allen, Bul. Amer. Mus. Nat. Hist., vol. 3 (1890-91), p. 277, 1891.       Type locality.--Beaver River, Beaver County, Okla.       General characters.--Big head and short body, long brush-tipped tail, long hind legs and feet, small hands, and ample fur-lined cheek pouches combine to produce a most unique and striking appearance. Upper parts, bright buffy-yellow with a white band crossing each flank and white spot over each eye; underparts and stripe along each side of tail, white. Measurements of Montana specimen: Total length, 264 millimeters; tail, 145; hind foot, 40.       Distribution and habitat.--Richardson kangaroo rats are common in eastern Montana and western South Dakota, and undoubtedly occur in North Dakota, although no specimens have been taken and the only actual evidences of their presence are some groups of burrows described by Doctor Bell, at Wade, on the Cannonball River. He describes groups of large burrows on a strip of sandy ground on the Wade ranch, with considerable earth thrown out around the entrances, exactly as had been found around their dens at Glendive, Mont., and in other parts of their range. The species can only tentatively be included in the North Dakota list, but should be watched for and will undoubtedly be found in a few localities over the western part of the State. The animals can not fail to be recognized, and usually their burrows and the long-paired tracks of their hind feet are unmistakable.       General habits.--As indicated by their large, dark eyes, the kangaroo rats are strictly nocturnal, and for this reason are rarely seen except as caught in traps or accidentally driven out of their burrows. They are gentle, timid little animals, depending entirely on speed and their deep dens for protection. In running they hop along on their hind feet, and when hard pressed take flying leaps through the air, balanced by their long, tufted tails. The little front feet are used as hands and rarely allowed to touch the ground.       Food habits.--The food of this species consists of a great variety of seeds and grain, which are gathered and carried in the cheek pouches to the dens, to be eaten at leisure. Most of the rats collected for specimens are found with more or less food and sometimes with the pouches distended with various seeds or grains.       [p.125] Economic status.--It is perhaps fortunate that these interesting rodents do not reach farther into the State as in grain-producing country they often levy a considerable tribute on the crops. Where they are abundant, the quantity of grain carried away, eaten, and stored in their dens for future use is sometimes a serious loss. Family GEOMYIDAE: Pocket Gophers Geomys bursarius (Shaw) Mississippi Valley Pocket Gopher (Pl. 16) Mus bursarius Shaw, Trans. Linn. Soc. London, vol. 5, p. 227, 1800.       Type locality.--Unknown; somewhere in the Upper Mississippi Valley.       General characters.--Characterized by heavy build, large front feet, and long, heavy, digging claws, conspicuously grooved upper incisors, and deep fur-lined pockets on the cheeks extending back under the skin to the shoulders; eyes and ears, small; tail, small and nearly naked at tip; fur, short, smooth, and glossy. Color, light chestnut-brown above, slightly paler on the belly. Average measurements: Total length, 270 millimeters; tail, 80; hind foot, 35. A large female at Grand Forks measured 290, 75, and 35 millimeters, and weighed 14 ounces. FIG. 7.--Records of two species of pocket gophers in North Dakota: Triangles, the Mississippi Valley pocket gopher; circles, the Dakota pocket gopher; dot in circle, type locality. The paler sagebrush pocket gopher from the extreme western part of the State is not shown on this map       Distribution and habitat.--The Mississippi Valley pocket gophers enter eastern North Dakota and range as far West as Ludden, Oakes, Larimore, Valley City, 10 miles west of Portland, Manvel, Grand Forks, and to the vicinity of Pembina (fig. 7). At Hankinson, in 1912, the writer found them abundant over the prairies, especially in mellow, sandy soil. On the high clay hills south and west of Lake Elsie they were scarce or entirely absent from extensive areas. A fondness for mellow soil seems to be a potent factor in outlining the range of the species. At Fairmount, Sheldon found them occupying mellow [p.126] soil along the river and a few scattered out on the wide, low prairies. At Oakes he found a few and at Lidgerwood they were abundant and very destructive to crops. At Wahpeton, Kellogg and the writer found them common along the river valley, and noted a few over the prairies, where they were doing considerable mischief in grain and alfalfa fields. At Lisbon, in 1912, Eastgate took a few specimens, but reported the animals scarce. In 1892, Loring took specimens at Valley City, Castleton, Wheatland, Buffalo, Erie, Portland, and vicinity. At Fargo, in 1912, their hills were abundant over the valley, except on some of the farms where the pocket gophers had been trapped. The hills were large and a long row of them across a green field of young wheat showed up strikingly. At Larimore, in 1915, Kellogg was told by the residents that these large pocket gophers had been the original species there, but the little gray form, Thomomys talpoides rufescens, had come in recently; at Manvel, Grand Forks County, he collected a specimen of Geomys and reported it as the common gopher of that region and especially numerous along railroad tracks. At Grafton, only Thomomys was caught, but the large hills of Geomys were seen at Minto, 10 miles farther south. In 1916, the writer took Geomys just across the Red River from Pembina, where gopher hills were common on a strip of mellow soil, and specimens have been taken at Emerson, just above the Manitoba line. Thus the range has been rather fully worked out and found to extend on the west little beyond the old beach lines of postglacial Lake Agassiz.       General habits.--For a distance of more than 1,000 miles, roughly from Pembina to El Paso, the ranges of Geomys and Thomomys meet without any extensive overlapping, Geomys occupying generally the mellow soil of the fertile valley country and Thomomys the higher, drier, and often more sterile soils to the west. The reasons for this division of territory have caused much speculation, and to obtain some evidence on the question, the writer made a special effort to get living specimens of both to test their dispositions when placed together. A live Thomomys was placed in the cage with the larger Geomys. Without a moment's hesitation the old 14-ounce Geomys pounced upon the 5-ounce Thomomys and began to chew it up, catching it by the ribs and crushing its bones, ribs, neck, skull, shoulders, and legs. When convinced that it was entirely dead the Geomys left it and showed no further interest in the victim. Its bones were broken to bits, but the skin was not cut through, probably because the teeth of the Geomys had been dulled on the wires of its cage. This fierce animosity seems to afford a reasonable explanation of the division of range between the two genera, the larger and more ferocious occupying the choice, fertile portion of the country and leaving the rest to its weaker relative.       To test further the disposition of Geomys, two that had been caught alive were placed near together, the old female that had chewed up Thomomys, and a half-grown young male caught near her home and quite probably one of her last spring's young that had been long ago sent out to dig its own way in the world. As they met face to face both hissed, struck out with their hands, and clashed their incisors together, the larger forcing the smaller one backward, but they did not clinch, and neither gave the other a chance to get [p.127] a hold. Again and again they jumped at each other, hissing and blowing, striking or pushing with their hands, and striking their incisors together with loud clicks, but doing no damage. The smaller animal was constantly forced backward and evidently would have retreated into its burrow had it been within reach. They were separated before any damage was done, but not until they had fully demonstrated the fact that they are not sociably inclined.       Later, while in a cold room in a little hotel, the writer placed a meadow mouse, Microtus drummondi, in the glass bowl with the smaller Geomys. Both were chilly and it was hoped they would keep each other warm. At first "Mike" jumped at "Geo" and bit and squeaked at him, but did not stir up any trouble, so he went over to one side, of the bowl and made a nest for himself in the grass. It was thought they were going to be friendly and would be company for each other, but later in the evening Mike was heard to squeal; when the writer reached him Geo was making his bones crack. It was too late to intervene, and when Geo let go Mike was limp and dead. He was left to see what would happen, and in the morning the victim's bones were found broken to bits, although his skin was intact and no attempt had been made to eat him. While the Microtus may have started the trouble, for its disposition is not amiable, this further demonstration of the unsociable nature of Geomys is worth recording.       Later, after Geomys had become perfectly tame and was no longer interested in eating the writer nor in running away from him, its real nature and disposition were more apparent. It had no objection to being picked up and petted, but if startled would throw up its head as if ready to bite, so that it seemed safer to avoid its nose. If not startled it would take food and climb into the hand to be taken up and carried about.       It would make a large, warm nest in its nest box by carrying in grass, paper, cotton, or any soft material until the box was well filled, then going in would stuff the doorway full and remain buried in its nest, sometimes for 12 or 24 hours at a time. It would sleep longer and eat less in cold weather than in warm.       When awake it would insist on strenuous exercise, eating, chewing up nest material, digging, scratching, and gnawing, or, if out of its box, running around the room for an hour or more at a time at a steady, rapid trot. At first it would butt into every object encountered as it followed the walls around and around, but later seemed to recognize and avoid every obstacle. Finally it became so familiar with the room that it would run in a large circle, missing all the furniture, unless something was moved into its path, when it would promptly bump into it. Its eyes were generally kept open while running, but in a lighted room they seemed to be of little help. In the dark it seemed to see well at close range, and when a nut was held in the fingers well inside its nest door it would take the nut gently without touching the fingers with its teeth. This, however, may have been due to the sensitiveness of its abundant short mustache more than to sight.       Its hearing seemed very dull, except for certain sounds. A touch, scratch, or jar on his house or its nest box would rouse the animal instantly from sleep and put it on the alert, while loud talking, [p.128] music, or open-air sounds seemed to make no impression on it. At first a puff of air or a door being opened across the room would attract its attention, and it could be stopped in its headlong race across the room by a puff of the breath.       Mentally it seemed dull and apathetic, although physically powerful and energetic. It has never shown any play instinct, but was probably too old when captured.       The animal was unable to swim. When put in a bathtub half full of water it floated with its head and back well out, but kicked or tried to run with its usual one foot at a time gait, and made no progress whatever. Apparently pocket gophers are unable to swim, and this may account for some peculiarities in their distribution in other parts of their range.       Pocket gophers have been supposed to have no voice. When caught in a trap or held in the hands against their will they make a hissing or blowing sound by forcing the breath rapidly out and in. This was suppose to be their only sound, but the tame pet on several occasions when hurt or troubled made a low, throaty chur, chur, chur in a complaining tone that seemed to be a real voice.       These powerful little burrowing animals live solitary lives almost entirely below the surface of the ground, and most of the time in total darkness behind closed and well-packed doorways. Their eyes and ears are of little use to them and have become almost rudimentary, but their tails, with sensitive tips, serve an important function in guiding their retreats in their shuttlelike motions back and forth through their extensive tunnels.       With their powerful claws they dig up the earth and push it before them to some point where a temporary opening is made through which it is thrust to the surface of the ground. The little mounds, or gopher hills, that dot the fields and prairies where they live are rapidly made. Load after load of the loose earth is pushed in front of the hands and breast to the entrance and thrown out with a little toss until the gallery is cleaned, and the last few loads are firmly packed in the entrance to close the burrow. Sometimes a few quarts and sometimes a bushel of earth are thrown out in one heap, but there is always the little circular dent, where the last load was pushed up and left in the mouth of the burrow, and often the direction of slope to the burrow below may be known from the greater quantity of earth on one side of the doorway. Later another doorway is opened up to the surface 10 or 20 feet away and another hill thrown up, and so on, day after day, until a long line of hills is formed, or a group if the burrows wind about and among each other.       In 1887, the writer counted the fresh hills thrown up by three pocket gophers 12 days after a rain, and the number of mounds that had not been rained upon were 28, 35, and 40. These hills averaged about 6 quarts of earth each, or approximately 17 quarts a day thrown out by one pocket gopher.       In summer the tunnels are about 10 inches or a foot below the surface, but in winter they run deeper and probably keep below the frozen earth, except at the entrance, where many are kept open to the surface. From these openings the animals push their way through the snow along the surface of the ground, leaving tunnels that later are filled with the loose earth from their burrows.       [p.129] Pocket gophers do not become fat or actually hibernate, but they store up food to some extent, probably for winter use.       Breeding habits.--Long and widely known as these animals have been, it seems strange that there is so little information available regarding their breeding habits. Once on a Minnesota farm, two naked young were found in a nest chamber in the burrow. Their eyes were closed, their skin was delicate, pink, and hairless, and their little round heads and fat chubby hands were almost baby-like. The number of young, as shown by embryos in females collected for specimens is 2 to 6, with apparently 4 the most common. The mammae of the females are arranged in two pairs of inguinal and one pair of pectoral. Only the small young are found in the burrow with the mother. As soon as they are old enough to dig for themselves, and before half grown, they branch off into new galleries, which finally become closed behind them when their solitary careers begin. Most of their lives are solitary, but in the mating season in spring a male and female are occasionally caught in the same burrow. The male soon leaves, however, and takes no further interest in the family affairs. Their reproduction is not rapid, but they are so well protected from enemies above that they increase steadily unless their abundance is controlled by artificial means.       Food habits.--The food of pocket gophers consists entirely of vegetable matter, largely roots encountered in their underground tunnels but also a great variety of green plants from above ground. When the opening is first made to the surface, the pocket gopher examines the plants close by and usually cuts them and fills its pockets before throwing out the earth, sometimes making several trips back to empty its pockets and fill them again before it throws out the earth and closes the doorway. Thistles, dandelions, clover, alfalfa, and leguminous plants generally are favorite foods, but grass, grain, and a variety of other plants are taken as encountered, and the pockets are often stuffed with leaves and stems intended for food or nest material. The many little bulbs, as wild onions, lilies, and the tuberous roots of native plants, are sought for food, but the soft and tender roots of many other plants are eaten, as well as the bark from even the woody roots of shrubs and trees. The contents of stomachs of pocket gophers usually show a combination of green plant tissues and the finely chewed white or light-colored pulp of roots and bulbs. At times ripe grain is eaten, but generally green food seems to be preferred, or is more easily obtained.       Economic status.--In many localities pocket gophers are among the most destructive of rodent pests, as they prefer many of the cultivated crops to wild food and steadily gather into fields where potatoes, turnips, or other root crops are raised, and also into fields of clover and alfalfa and the best of tame-grass meadows. In grainfields they do extensive damage, but are partly kept out by the plowing of the land and by the long period of scant food in the stubble. In orchards and dooryards they also do much damage, eating the roots from fruit trees and ornamental shrubs, and often killing many of the choicest varieties. Their destruction is imperative in any well-kept agricultural land, and in limited areas this is not difficult. They are easily trapped or poisoned, and detailed methods for their [p.130] most economical destruction have been worked out by the Biological Survey. Circulars or leaflets giving the best methods can be had on application. Thomomys talpoides rufescens Wied Dakota Pocket Gopher Machtóhpka of the Mandans (Maximilian); Mánica of the Dakotas (Gilmore); Cipans of the Arikaras (Gilmore); Kípapudè of the Hidatsas (Gilmore). Thomomys rufescens Wied, Nova Acta, Acad. Caes. Leop.-Carol. Nat. Cur., t. 19, pt. 1, p. 378, 1839.       Type locality.--Fort Clark, N. Dak.       General characters.--Smaller and slenderer than the Mississippi Valley pocket gopher, which comes into eastern North Dakota. Upper incisors, not noticeably grooved except in a fine line near inner edge of each tooth; large fur-lined cheek pockets on each side of face reaching back under skin to shoulders; front feet and claws, large; hind feet, comparatively small; tail, nearly naked at tip; fur, short, smooth, and glossy. Color of upper parts, dull brownish-gray; underparts, buffy-gray, often with white markings on chin, throat, and breast. Measurements of adults. Total length, about 240 millimeters; tail, 70; hind foot, 31. Weight of adults, 5 or 6 ounces.       Distribution and habitat.--The Dakota pocket gophers cover the greater part of North Dakota and extend into eastern South Dakota and southwestern Manitoba. Their range covers practically the whole State except the low part of the Red River Valley, south of Grafton, and the western edge of the State, where a slightly different form occurs at the junction of the Yellowstone and Missouri, and probably along the Little Missouri River Valley. The eastern border of their range in the State is marked by Pembina, Drayton, Grafton, Larimore, Portland, Valley City, and a point 4 miles southeast of Ellendale, in an irregular line following closely the old shore line of Lake Agassiz, and also marking the western edge of the range of the larger Mississippi Valley pocket gopher, Geomys bursarius. The cause for this limitation of range may be due to antipathy of the two species, or to combination of factors; nowhere do the two overlap to any great extent. The fact that Thomomys avoids low or wet ground and is partial to high, dry prairies may be one of the determining factors of this border line.       Over all the high open prairie country and often in the timbered areas of the Turtle Mountains and Pembina Hills, these pocket gophers are found in dry meadows, fields, clearings, openings in brushy land, and sometimes even in scattered timber. At Pembina, in 1887, the writer found them common everywhere, except in the thickest growths of trees along the river, and took specimens on both sides of the river as well as on both sides of the border line. A few were found in fields, but they were most abundant over the unbroken prairie, where their favorite food plants were growing. In 1892, Loring succeeded in trapping a specimen at Portland, but in six days' subsequent trapping found no others, so that evidently this was somewhat beyond their regular eastern limit. At Larimore he found them abundant 4 miles west of town, but none farther east, and at Sherbrooke he found them common, as also at Valley City and Jamestown. In the northwestern corner of the State, [p.131] about Kenmare and Crosby, pocket gophers were comparatively scarce in 1915, as their characteristic little mounds were noticed only in scattered localities.       At the type locality of the species, which was visited in 1909 to obtain specimens for determining the validity of Maximilian's name, the pocket gophers were common over prairie and river flats on both sides of the river, occupying both the dry, sandy bottomlands and the high heavy-soiled prairie. Later in 1913, Jewett also found them common over that part of the valley, in the Killdeer Mountains, and farther south in the vicinity of Glen Ullin and Mandan. In 1893, Fisher reported them very common at Bismarck. In 1915, Sheldon traced them across the southern part of the State, from a point 4 miles southeast of Ellendale, westward continuously to Napoleon, Dawson, and Cannon Ball. The same year Kellogg traced them across the northern part of the State from Grafton to Devils Lake, Towner, the Missouri River at Oakdale, and thence down the river to Bismarck. Thus the reports cover practically the whole State and indicate fairly definitely the range and abundance of the species.       General habits.--In many places throughout their range these pocket gophers will average one or more to the acre and their total numbers over the State are enormous. Their presence can always be recognized by the little mounds of earth heaped up in the prairie grass and containing usually from 2 quarts to a peck of earth. Many of these mounds, however, are enlarged by repeated excavations until they contain a bushel or more, and some measured at Pembina, in 1887, were 3 by 3 feet, and 7 inches high, 4 by 4 feet, and 10 inches high; 4 by 5 feet, and 6 inches high; and 4 by 5 feet, and 7 inches high. These, however, were all composite mounds where the earth had been thrown out several times on successive days.       Practically the whole life of the animals is spent underground, where they burrow continuously from point to point, usually 6 inches to a foot below the surface of the ground, bringing out the loose earth by pushing it to the surface in the familiar little mounds, then securely closing the doorways, so that no enemy can enter their homes. Sometimes the row of mounds stretches away for 50 to 100 yards in almost a straight line; they are usually 6 to 8 feet apart, but sometimes 10 to 20 feet, while between some of the larger hills a space of 27 feet has been measured. More often the tunnels wind about and they sometimes form groups, where one of the animals has worked all summer on a few square rods of ground, so that the lines of old and new mounds crisscross and overlap.       The burrows pass through ground that is full of choice food in the form of roots, bulbs, and tubers. Some green food is gathered and tucked into the pockets at the entrance of their burrows, but aside from this the animals rarely come out on the surface of the ground unless for a few seconds at a time when they are throwing out the earth. The earth is pushed out in front of them in little loads about half the size of their bodies, and so quickly that it has the appearance of being thrown from them. Most of the people living in the country where they are abundant never see them, and pocket gopher is misapplied to the ground squirrels. In winter they go deeper so as to escape the [p.132] frost, but keep their burrows open to the surface and often come out under the snow and tunnel long distances to obtain green vegetation, afterwards filling these surface tunnels with earth from below. They do not become very fat and evidently are active throughout the winter.       Breeding habits.--Apparently but one litter of young is raised in a season and judging from the immature specimens caught in July and August these are born some time in June. A record of five embryos, about one-third developed, taken at Carberry, Manitoba, June 29, 1892, by Ernest Thompson Seton (1909, vol. 1, p. 567), seems to furnish the only positive data available for this subspecies, although records for other forms of the same group, with the same arrangement of mammae, two pairs of inguinal, two pairs of abdominal, and one pair of pectoral, indicate a normal litter of six young. Practically nothing is known of the nest and underground habits of these animals, and the small young seem not to have been recorded. Few animals are more solitary in habits, and only during the mating season in spring are a male and female occasionally trapped from the same burrow. The male soon leaves, however, and probably never sees the young. The mother cares for her family until they are about half grown, when they start burrows of their own and are soon shut off from parental care, each beginning a life that is to be mainly solitary. Although breeding but once a year, their increase is comparatively rapid, as they are unusually well protected from enemies.       Food habits.--These pocket gophers live almost entirely on roots and green vegetation, and although they are very partial to certain species of plants, they will eat almost anything that comes in their way if better food is not available. The prairie clover (Psoralea argophylla), prairie turnip (Psoralea esculenta), and wild licorice bush (Glycyrrhiza lepidota) are apparently their favorite wild foods over much of the prairies, and their mounds often become very numerous where these plants are abundant. In their pockets are found the leaves and stems of a great variety of other plants, including grass, lupines, and other legumes, and occasionally roots and tubers, but apparently these are not often brought to the surface. Sometimes the pockets are found stuffed so full of green vegetation that they more than double the apparent size of the animal's head. They are used only for carrying food and not, as is sometimes reported, for carrying earth out of the burrows. To what extent roots, tubers, and bulbs are stored for winter food is not well known, but occasionally well-filled storage cavities are found along the lines of the tunnels.       Economic status.--Next to the ground squirrels, these gophers are generally the most destructive rodent pests of the region where they live. Although for ages they have been industriously plowing and mellowing the prairie soil, burying the surface vegetation and enriching and improving the land, they at once become the farmer's enemy when occupying the ground with his crops. Even on the prairies they destroy or consume much of the choice grass that would otherwise be available for stock, and cover up and prevent the economical cutting of much of the wild hay on the prairie and the best parts of the dry meadows.       [p.133] In fields, gardens, and orchards, however, they do the most harm. Entering through their safe tunnels they find choice food in the clover and alfalfa fields, and if nothing better can be found will live all summer on the green stems, leaves, and heads of grains. In vegetable gardens they are even more destructive, cutting the peas and beans above the ground and drawing them into their burrows to be eaten, or, without the risk of appearing at the surface, taking the onions and turnips or following a row of potatoes and cleaning the tubers from each hill in succession. Nowhere is their mischief more exasperating than in a clean and well-kept orchard, where, lacking other food, they often eat the bark from the roots of the trees and leave them to die, or even cut off so many of the roots that the trees dry up and tip over with the first wind.       Fortunately, pocket gophers are easily controlled, and it is only necessary to know how to poison or trap them in order to protect crops and trees. Where only a few are doing mischief, the simplest method is to trap them by merely opening their doorways and setting traps that will catch them as they come out to close the openings. Armed with a few modern traps and an old table knife, anyone can, with a little practice, catch all the pocket gophers in an ordinary garden or orchard without much loss of time. Where the mischief is on a larger scale, poison is a more rapid and economical control measure. Simple directions can be obtained from the Biological Survey for the most effective methods of administering poison.       Although excellent food and in every way perfectly suitable as a food animal, pocket gophers are not large enough to be of importance as game. In places where it is necessary to catch considerable numbers of them, however, they can be used to advantage as food, and if properly dressed and cooked are as good as rabbit or squirrel. Thomomys talpoides bullatus Bailey Sagebrush Pocket Gopher Thomomys talpoides bullatus Bailey, Proc. Biol. Soc. Washington, vol. 27, p. 115, 1914.       Type locality.--Powderville, Mont.       General characters.--Very similar to rufescens but noticeably lighter and brighter colored, with conspicuously larger audital bullae. Measurements of type specimen: total length, 238 millimeters; tail, 72; hind foot, 30. Weight of female, from Buford, 5 ounces.       Distribution and habitat.--The arid sagebrush-valley form of pocket gopher occupies mainly the Yellowstone and Missouri Valleys of Montana, but comes into North Dakota at Buford and is probably the form occupying the Badlands part of the Little Missouri Valley, as specimens have been referred to it from the valley just below the southwest corner of the State. In an arid, open habitat, often with sandy or light-colored soils, these pocket gophers have become adapted to their environment in coloration, but in general habits show only such differences from rufescens as are occasioned by the conditions under which they live. Over the open range country they are of little economic importance, but as many of the valleys are brought under irrigation with intensive cultivation, they become of serious consequence and their destruction is necessary to satisfactory returns from the cultivated areas.       8 Glaucomys volans volans (Linnaeus). There is still a possibility of finding this little flying squirrel in extreme southeastern North Dakota, as it ranges northward into central Minnesota and could readily extend into the Red River Valley at Wahpeton.       9 For diagrams and descriptions of burrows and general habits see Johnson, G. E. (1917, p. 261).       10 Measurements from North American Fauna No. 40 (Hollister, 1916, pp. 16-17).       11 Measurements from North American Fauna No. 37 (Howell, 1915, p. 26).       12 Weights of more than 2 pounds have been recorded.       13 Mice that live in the buffalo skulls, most likely this species.       14 There is some confusion as to which species of mouse this name should apply. Doctor Beede gave it as one of the names of the bean mouse (Microtus p. wahema, p. 94), but it is not the name in common use by the Dakotas and does not suggest a diurnal, ground dwelling species, but rather a wholly nocturnal and partly arboreal one. The mice that nibble the edge of the full moon until it is all eaten up must be good climbers, and Doctor Gilmore thinks the name probably applies to one of the white-footed mice. As it is doubtful whether the Dakotas distinguished the very similar forms of Peromyscus, this most arboreal of their species is chosen for the beautiful name.       15 This name is merely a general term for mice (George F. Will).       16 Omaha name contributed by Doctor Gilmore, Intshunga wahema, the burying mouse, from its habit of storing food in the ground.       17 For further information on the habits and control of beavers, see U. S. Dept. Agr. Bul. 1078 (Bailey, 1922) and Misc. Circ. 69 (Bailey, 1926). Title Pages & Contents     Introduction     Part I.     Part II. Introduction     Part II. Artiodactyla     Part II. Rodentia     Part II. Lagomorpha     Part II. Carnivora     Part II. Insectivora     Part II. Chiroptera     Bibliography     Index     Scanned and formatted by Kathryn Thomas North Dakota State University Libraries June 14, 2002