North American Porcupine (Erethizon dorsatum)

North American Porcupine (Erethizon dorsatum) FAMILY: Erethizodontidae North American Porcupines are large, slow-moving, tree-climbing rodents, protected from predators by their formidable quills. In winter, they eat the bark, phloem, and cambium of trees, particularly conifers. In spring and summer, they mostly forage on the ground, feeding on grasses, sedges, acorns, and flowers. They readily consume crops or gnaw on automobile tires, so are sometimes regarded as pests. Porcupine young are exceptionally well developed at birth. Their eyes are open and they have teeth and even quills, which are soft at birth but harden within a few hours. Within a week, they can feed on their own. Few predators even try to kill Porcupines with any regularity, except one, the fisher. Fishers attack Porcupines from the front, grabbing them by the face, thus avoiding the quills. Porcupines do not throw their quills - which are modified hairs - but the quills pull loose from the Porcupine when they are stuck into an adversary, and they have barbed tips, so they are not easily removed. Credit: painting by Todd Zalewski from Porc-epic, Hedgehog, Quillpig, Quiller Males are heavier than females. Average: 772 mm Range: 600-1,300 mm Range: 3.5-18 kg

American Beaver (Castor canadensis) FAMILY: Castoridae The largest North American rodent and the only one with a broad, flat, scaly tail, the Beaver is now common and widespread, even in areas it did not inhabit during pre-colonial times. The modifications it makes to the environment by felling trees and building dams result in changes to plant, animal, and microbial communities that are sometimes desirable and sometimes not. The Beaver itself is not easily seen, being nocturnal and secretive, but it can be spotted in ponds, lakes, or large streams at twilight by a quiet observer. Its pelage is brown, with gray underfur, and is prized by trappers. The webbing on its hind feet help it to swim; claws on the digits of its forefeet give it dexterity in handling food; comblike claws on its hind feet help it in careful grooming; and it can close its mouth behind its front teeth, so that it can carry woody material without taking in water. Beavers cache and consume the inner bark of both deciduous and evergreen shrubs and trees, as well as terrestrial and aquatic plants. Their young, called kits, leave the colony at the age of six months. Credit: painting by Todd Zalewski from Canadian Beaver, North American Beaver None Range: 1,000-1,200 mm Range: 16-30 kg

Yellow-faced Pocket Gopher (Cratogeomys castanops) FAMILY: Geomyidae The Yellow-faced Pocket Gopher feeds on starchy, tuberous roots of desert shrubs and on the roots and leaves of low-growing forbs. Like other pocket gophers, this species is considered an agricultural pest, doing extensive damage in orchards, gardens, potato patches, and other croplands. It digs long burrow systems, preferring deep sandy or silty soil. Burrow systems seem to contain only one nesting chamber, and except when breeding or raising young, these animals live alone. Yellow-faced Pocket Gophers live from less than one year (males), to a little more than one year (females). Females may reproduce within the same season as their birth and can have up to three litters in a season. Litter size averages 2-3, and ranges from 1-5. Cratogeomys castanops - yellowish variation, left; reddish variation, right Credit: painting by Elizabeth McClelland from Males are larger than females. Range: 220-315 mm Range: 385-410 g males; 225-290 g females

Texas Pocket Gopher (Geomys personatus) FAMILY: Geomyidae Only soils with low percentages of silt, clay, and gravel will do for the Texas Pocket Gopher, so many of its populations are isolated from one another. The species occurs in southern Texas and extreme northeastern Mexico, burrowing in deep, sandy soils and only infrequently emerging aboveground. It forages on plant root systems, and is capable of pulling some plants through the soil and into its burrow. While in the burrow, Texas Pocket Gophers keep any entrance to the surface plugged with soil; this closed-door policy not only helps to keep out unwanted guests, it also helps to maintain a suitable subterranean environment. Variation in size is one notable trait of the species, probably a result of population isolation. Credit: painting by Elizabeth McClelland from South Texas Pocket Gopher, Carrizo Springs Pocket Gopher, Del Rio Pocket Gopher, Nueces Pocket Gopher, Padre Island Pocket Gopher, Rio Grande Pocket Gopher, Seaside Pocket Gopher Males are larger than females. Average: 270 mm Range: 216-360 mm Range: 165-400 g

Botta's Pocket Gopher (Thomomys bottae) FAMILY: Geomyidae Pocket gophers dig with their front claws and with their teeth. A pocket gopher can close its mouth behind its front teeth, so it can dig without getting a mouthful of dirt. Its "pockets" are fur-lined, external cheek pouches, one on each side of its mouth, which it uses to transport food. Botta's Pocket Gopher has an extremely broad geographic range, and individuals vary widely in appearance: they can be nearly white, gray, brown, or blackish-brown. They vary in size, too. Males are larger than females. Males grow throughout their lives, whereas females stop growing after their first pregnancy, so older males can be much larger than females. Pocket gophers live in small, local populations, spending almost their entire lives underground in their network of burrows. Credit: painting by Elizabeth McClelland from Valley Pocket Gopher Males are larger than females. Range: 170-280 mm males; 150-240 mm females Range: 110-250 g males; 80-160 g females

Gulf Coast Kangaroo Rat (Dipodomys compactus) FAMILY: Heteromyidae Gulf Coast Kangaroo Rats are confined to barrier islands of northeastern Mexico and southern Texas and the nearby Texas mainland. No fossils of this species have been found, but because of features of its teeth and skull, scientists think it is the most primitive living species of kangaroo rat. It has five toes on each hind foot, unlike most kangaroo rats, which have four. Seeds are its main food, although it also eats insects. Unlike Ord's Kangaroo Rat, which shares part of its range, it can take advantage of areas that have been cleared for farming and ranching. It must have soft soil to dig its burrows, however, whereas Ord's Kangaroo Rat usually lives where the soil is hard-packed and vegetation is thick. Credit: painting by Elizabeth McClelland from Males are larger than females. Average: 228.1 mm males; 227.6 mm females Range: 203-255 mm males; 210-266 mm females Average: 53 g males; 45 g females Range: 46-60 g males; 44-46 g females

Hispid Pocket Mouse (Chaetodipus hispidus) FAMILY: Heteromyidae "Hispid" refers to the coarseness of this pocket mouse's fur. Hispid Pocket Mice are larger and more robust than other pocket mice in their range, and like the others, they are solitary except in the breeding season. The gestation period is not known, but females in the northern part of the range may have two litters of 4-7 young a year. In the southern part of the range, mating activity has been seen year-round. None Range: 198-223 mm Range: 30-47 g Credit: painting by Elizabeth McClelland from

Mexican Spiny Pocket Mouse (Liomys irroratus) FAMILY: Heteromyidae The Mexican Spiny Pocket Mouse occurs in central and northeastern Mexico and the extreme south of Texas. It inhabits a variety of semi-arid brushy or rocky habitats, and is common where it lives. The "pockets" of the pocket Mouse are fur-lined cheek pouches, where seeds are carried from the foraging area to the burrow. Mexican Spiny Pocket Mice are grayish-brown, with white underparts. On the back, a mixture of stiff spiny hairs and soft ones gives the animal a somewhat coarse appearance. These Mice are nocturnal and are active year-round. Credit: painting by Elizabeth McClelland from Males are larger than females. Average: 238 mm males; 226 mm females Range: 216-262 mm males; 207-251 mm females Range: 40-60 g males; 35-50 g females

Merriam's Pocket Mouse (Perognathus merriami) FAMILY: Heteromyidae Merriam's Pocket Mice are found in short-grass prairie, desert scrub, and open, arid brushland. They are most common where the vegetation is dense enough to provide them with seeds and some protection from predators, but not so dense that it inhibits their movements. Grazed pastures suit their needs well. Their silky fur is yellowish-orange with a slight blackish tinge on the back, and their bellies are white to pale buff. A dark stripe runs just behind the nose, and a pale ring encircles each eye. They are very similar in appearance to Silky Pocket Mice and Plains Pocket Mice. They are docile, readily tamed, and easily kept in captivity. None Average: 112 mm Range: 95-121 mm Average: 8 g Range: 5-9 g Perognathus merriami - indistinguishable visually from P. flavus; differentiated by territory Credit: painting by Elizabeth McClelland from

Northern Pygmy Mouse (Baiomys taylori) FAMILY: Cricetidae Northern Pygmy Mice are the smallest rodents in North America. They live in a variety of habitats where there is dense ground cover, and eat grass seeds and leaves, prickly pear cactus fruit and stems, mesquite beans, and granjeno berries (granjeno is an evergreen shrub). They will also eat snakes, snails, and insects if presented with them. They cope with desert heat by entering torpor. Males help care for the young, grooming them and returning them to the nest. Nests have been found under fallen logs or in thick clumps of grass. Young Mice reach sexual maturity quickly, females at about 60 days and males at about 70-80 days. The median life span is only 23 weeks, although captives, in laboratories, have been known to live as long as 170 weeks. Snakes and owls prey on them. Credit: painting by Wendy Smith from None Range: 87-123 mm Range: 6-9.5 g

Southern Plains Woodrat (Neotoma micropus) FAMILY: Cricetidae Southern Plains Woodrats are found in places where grasses, creosotebush, mesquite, and cactus grow. Local populations can reach high levels and then crash. Crashes can be associated with changes in habitat for example, an unusually rainy year may kill cactus the Woodrats rely on for food. Like many rodents, these woodrats are active between dusk and midnight. When disturbed, individuals thump or drum their hindfeet, possibly to communicate territorial ownership. They live in association with many other mammals, including armadillos, cotton rats, kangaroo rats, grasshopper mice, jackrabbits, and cottontails. Hoary Woodrat, Baird Woodrat, Black Woodrat, Plains Woodrat, Gray Woodrat, Rata de Campo Males are larger than females. Average: 370 mm males; 356 mm females Range: 334-411 mm males; 310-382 mm females Range: 210-317 g males; 180-274 g females Credit: painting by Ron Klinger from Kays and Wilson's Mammals of North America, Princeton University Press

Northern Grasshopper Mouse (Onychomys leucogaster) FAMILY: Cricetidae Northern Grasshopper Mice are highly predatory, and their skulls and teeth resemble those of flesh-eating carnivores such as cats and dogs. Their forelimbs, equipped with elongated fingers and claws, have developed great dexterity, so they are able to manipulate captured prey. These Mice have a complex social system, using howling vocalizations to broadcast information on sex, identity, body size, and location. Grasshopper Mice prey primarily on grasshoppers, crickets, and beetles, yet they incorporate some seeds into their diet, presumably a dietary preference retained from a seed-eating ancestry. None Range: 119-190 mm Range: 26-49 g Onychomys leucogaster - gray (left) and cinnamon (right) variations Credit: painting by Ron Klinger from Kays and Wilson's Mammals of North America, Princeton University Press

Coues's Rice Rat (Oryzomys couesi) FAMILY: Cricetidae Coues s rice rats prefer cattail-bulrush marshes for habitat. Like the closely related Marsh rice rat, Coues s is thought to be highly aquatic, active at night, and carnivorous. They are excellent climbers, and nest above the ground. Their nests are built either in cattails or in small trees. When they nest in cattails Coues s rats only use the cattail leaf to build their nests. In trees, the rats use a mix of plant materials for the nest. They tend to breed during the non-winter months, and may breed throughout the year when winter is mild. They usually have litters of five, after a gestation of about 25 days. The distribution of Coues s rice rat in the United States - limited to southern Texas - along with their restricted habitat preference makes this species one of the rarest rodents in the United States. Credit: painting by Ron Klinger from Kays and Wilson's Mammals of North America, Princeton University Press Reasca Rice Rat Males are larger than females. Range: 390-410 mm Range: 67-71 g My North American Mammals Field Guide Page 1 of 2

Marsh Rice Rat (Oryzomys palustris) FAMILY: Cricetidae Marsh rice rats are among the most common mammals inhabiting tidal marshes of the Gulf and Atlantic coasts. Being good swimmers, diving to 10 m and crossing 300 m stretches of water, and able climbers, these rice rats are suitably equipped for life in an environment where water levels fluctuate. They and Coues's rice rats are carnivores: they prey on crabs, clams, snails, fish, insects, baby turtles, and birds. As opportunistic feeders, they will also eat carrion and even some plant material. In some places, they breed throughout the year, and in other places, they breed from March to October. A litter of five, after a gestation of about 25 days, is typical. In a little over a week, the newborn rats' eyes open and they are beginning to nibble solid food. They are weaned before they are three weeks old. As with many nocturnal rodents, owls are the main predator. Orysomys palustris - lower image is silvery subspecies O. p. argentatus of Florida Keys Credit: painting by Ron Klinger from Kays and Wilson's Mammals of North America, Princeton University Press Rice Rat Males are larger than females. Average: 226 mm males; 217 mm females Range: 193-262 mm males; 191-253 mm females Average: 56 g males; 48 g females Range: 46-80 g males; 40-60 g females My North American Mammals Field Guide Page 2 of 2

White-footed Deermouse (Peromyscus leucopus) FAMILY: Cricetidae The White-footed Deermouse has a very wide distribution. It is the most abundant rodent in mixed deciduous and coniferous forests in the eastern United States, and is probably equally abundant near farms. Its habitat preferences are very different in southern Mexico, however, as it prospers in semi-desert vegetation. White-footed Deermice are excellent swimmers, and so are able to colonize islands in lakes with relative ease. They are not agricultural pests, and they are important ecologically because owls, weasels, snakes, and many other predators eat them. Individuals may live several years in captivity, but an almost complete turnover occurs annually in wild populations. In some places they carry the tick that transmits Lyme disease. Credit: painting by Wendy Smith from Wood Mouse, Deermouse, White-footed Mouse Range: 150-205 mm Range: 15-25 g

Fulvous Harvest Mouse (Reithrodontomys fulvescens) FAMILY: Cricetidae The fulvous Harvest Mouse is a nocturnal species that lives in grassy fields where there are shrubs. These Mice are good climbers, and build baseball-sized nests up off the ground, in vegetation. Winter nests are sturdier than summer nests. When a nest is occupied often by two Mice the one or two entrances are plugged. Fulvous Harvest Mice eat invertebrates when they are available, during the spring and summer, and switch to seeds in fall and winter. Along the Texas coast, where invertebrates are available year-round, they are the dominant item in the diet. Males and females seem to travel together, which suggests they may pair-bond in monogamous relationships, a rarity for mammals. These Mice live for about a year, and seldom longer than 14 months. Credit: painting by Wendy Smith from Males are larger than females. Range: 134-189 mm Range: 6.5-25 g

Hispid Cotton Rat (Sigmodon hispidus) FAMILY: Cricetidae The Hispid Cotton Rat's fur is sprinkled or streaked with blackish or dark brownish and grayish hairs. The Rats molt, losing and getting a new coat, three times in three months as they move through juvenile and subadult stages and into adulthood. Hispid Cotton Rats inhabit tall, dense grasses that protect them from birds of prey. Their range has recently expanded northward into central Virginia, Kentucky, northern Missouri, southern Nebraska, and northern New Mexico, and westward into western Colorado and the Imperial Valley of California. Where their range and the ranges of Prairie Voles and Pygmy Mice now overlap, the Hispid Cotton Rat appears to be competitively excluding these species. Sigmodon hispidus - upper right (with S. ochrognathus) Credit: painting by Todd Zalewski from Males are larger than females. Range: 224-365 mm Range: 110-225 g males; 100-200 g females

Common Muskrat (Ondatra zibethicus) FAMILY: Cricetidae Common Muskrats, so-called for their odor, which is especially evident during the breeding season, are highly successful semi-aquatic rodents. They occur in both brackish and freshwater lakes, ponds, streams, rivers, and marshes throughout much of North America, except in parts of the South where tidal fluctuation, periodic flooding, or drought limit their distribution. Common Muskrats have a variety of aquatic adaptations, including a rudder-like tail that is flattened side-to-side, partially webbed hind feet, and fur that traps air for insulation and buoyancy. Because their fur has commercial importance, they were taken to Japan, South America, Scandinavia, and Russia, and there are now feral populations in some places where they were introduced. Credit: painting by Todd Zalewski from Mudcat, Muskbeaver, Musquash, Muskrat Range: 410-620 mm Range: 680-1,800 g

Texas Antelope Squirrel (Ammospermophilus interpres) FAMILY: Sciuridae Notable for its running speed, the Texas Antelope Squirrel has the longest hindlimbs and tail of any antelope squirrel. In the field, the squirrels are noticeable because of the way they carry the tail arched forward over the back. This common inhabitant of the Chihuahua Plateau occurs in rocky habitats in desert mountain ranges, nesting in burrows or in between rocks and crevices, and eating various seeds, berries, and insects. Antelope squirrels do not hibernate--they are active year round. Trader Spermophile None Average: 226 mm Range: 220-235 mm Average: 110 g Range: 99-122 g Credit: painting by Todd Zalewski from

Black-tailed Prairie Dog (Cynomys ludovicianus) FAMILY: Sciuridae Although there are still large populations of this species, some have disappeared as a result of human activity. Black-tailed prairie dogs exhibit the most complex social behavior of all prairie dogs. Social groups called "coteries" live together in very large colonies called "towns." The largest town ever recorded stretched for 65,000 square km (25,000 square miles) under Texas prairie. An estimated 400 million prairie dogs lived there. Topographical or vegetational features serve to subdivide the towns into clusters of coteries. The members of each coterie cooperate to defend their territory against others. Black-tailed prairie dogs are active all year, although they may spend extended periods of time underground in winter. They breed in February or March and usually have 3 or 4 young, who are first seen aboveground in May or June. Credit: painting by Todd Zalewski from Males are larger than females. Average: 387.8 mm males; 371.2 mm females Range: 358-429 mm males; 340-400 mm females Average: 907g males; 863 g females Range: 575-1,490 g males; 765-1,030 g females

Southern Flying Squirrel (Glaucomys volans) FAMILY: Sciuridae Most of the Southern Flying Squirrel's range is east of the Mississippi River, but it occurs west of the river in central Texas, and as far south as Honduras, in Central America. Like the Northern Flying Squirrel, it has a gliding membrane (patagium) and a flattened tail. Flying squirrels are nocturnal and are much smaller than most tree squirrels, which are diurnal. Although primarily associated with hardwoods, especially oaks and hickories, Southern Flying Squirrels inhabit forests of diverse types, and even live in cities and suburbs. A natural cavity or old woodpecker hole in a live or dead tree is the typical nest site. Where the ranges of the two species of flying squirrels overlap, it appears the Southern Flying Squirrel may out-compete its larger relative. Glaucomys volans - left (with G. sabrinus); G. volans' belly hairs are white at base and tip Credit: painting by Todd Zalewski from Eastern Flying Squirrel Average: 231 mm Range: 198-255 mm Average: 70 g Range: 46-85 g

Eastern Gray Squirrel (Sciurus carolinensis) FAMILY: Sciuridae The adaptable, omnivorous, diurnal Eastern Gray Squirrel is the native American mammal people most frequently see east of the Mississippi River. It prefers to den inside trees, but will construct large nests of leaves in the canopy if tree cavities are not available. An average of two to three blind, hairless young make up a litter. Litters are produced once or twice a year, in February and March and again in July through September. The young are weaned at eight or nine weeks, when their previously protective mother abandons them. In September, yearlings and some adults strike out to establish their own home ranges in a process called the "fall reshuffle." These home ranges are rarely more than one or two hectares in size. Successful as they are, Eastern Gray Squirrels live only 11-12 months on average, but some individuals have survived more than ten years in the wild. Factors affecting survival include the severity of winter, abundance of food, and parasites. One parasite, the mange mite, may cause enough hair loss to threaten survival through winter. Sciurus carolinensis - typical gray, left; black variant, right Credit: painting by Todd Zalewski from Cat Squirrel, Migratory Squirrel None Average: 473 mm Range: 383-525 mm Average: 520 g Range: 338-750 g My North American Mammals Field Guide Page 1 of 2

Eastern Fox Squirrel (Sciurus niger) FAMILY: Sciuridae Eastern Fox Squirrels have long, foxtail-like tails, which they flick when they are excited. They and Eastern Gray Squirrels are alike in many ways. They breed at the same time of year, nest in the same kind of places, and eat the same foods. However, Fox Squirrels prefer more open habitat, whereas Grays prefer good tree cover. Fox Squirrels spend more time foraging and running about on the ground than do the grays, and may be encountered in fields quite far from any trees, where gray squirrel would not stray. Both species feed on acorns, which are rich in tannins. Tannins are poisonous to many animals, including worms, and keep the squirrels free of roundworms and tapeworms. Fox Squirrels accumulate another chemical compound, porphyrin, in their bones and teeth, which makes their bones and teeth pink and bright red under ultraviolet light. Here's a mystery: Gray Squirrels eat the same foods and this does not happen to them nor to any other healthy mammal. Sciurus niger - typical color, right; southeastern variation, top left; black variation, center top; black-headed variation, lower center Credit: painting by Todd Zalewski from Fox Squirrel, Cat Squirrel, Stump-eared Squirrel None Average: 595 mm Range: 454-698 mm Average: 800 g Range: 696-1,233 g My North American Mammals Field Guide Page 2 of 2

Mexican Ground Squirrel (Ictidomys mexicanus) FAMILY: Sciuridae Mexican Ground Squirrels have adapted well to human activity and are common inhabitants of roadsides, cemeteries, and golf courses. They are omnivores, feeding on the seeds of a variety of grasses and forbs, green plant material, and larval and adult insects. This burrow-dwelling species can be found in small, social colonies. Alarm calls alert members of the colony to the presence of danger, and an erect posture is used to watch for potential predators. The species may be confused with the closely-related thirteen-lined Ground Squirrel, because both are marked by rows of white spots on the back. However, the Mexican Ground Squirrel has a paler coloration and larger body size. Spermophilus mexicanus - upper right (shown with S. spilomosa (center) and S. washingtoni (lower left)) Credit: painting by Todd Zalewski from Gopher, Picket Pen Males are slightly larger than females. Range: 280-380 mm Range: 137-330 g My North American Mammals Field Guide Page 1 of 2

Thirteen-lined Ground Squirrel (Ictidomys tridecemlineatus) FAMILY: Sciuridae Thirteen-lined Ground Squirrels are often seen standing on their hind legs on roadsides or other places where grass is mowed, such as lawns, golf courses, or cemeteries. The squirrels probably once lived in short-grass prairie, and some human habitats suit them well. They dig a variety of burrows, from short ones used for escape to deeper, longer ones with nesting chambers. Like most ground squirrels, they hibernate. In hibernation, their heartbeat slows from more than 200 beats per minute to no more than five. How long they spend in hibernation annually depends on where they live, and at what elevation. Day length seems to determine when they enter hibernation in the fall, and some sort of internal clock prompts them to emerge in the spring. The Thirteen-lined Ground Squirrel's coat pattern is unique, with 13 dark and pale stripes running the length of the back; the dark stripes are patterned with small white spots. Credit: painting by Todd Zalewski from Gopher, Striped Ground Squirrel, Striped Gopher, Thirteen-lined Gopher, Striped Spermophile None Average: 250 mm Range: 170-310 mm Range: 110-140 g My North American Mammals Field Guide Page 2 of 2

Spotted Ground Squirrel (Xerospermophilus spilosoma) FAMILY: Sciuridae Spotted Ground Squirrels are among the smallest ground squirrels in North America. They inhabit arid and semi-arid regions of Mexico and the Southwest, and are found in scrubland and grassland as far north as Wyoming and Nebraska. They feed primarily on green grasses, forbs, and seeds, but also eat insect larvae, insects, and even small vertebrates such as lizards and kangaroo rats. Their principal predators include snakes and hawks. In the northern part of their range, they hibernate for long periods. It is not known whether this also occurs in the most southern reaches of the range. Gopher Range: 185-253 mm Range: 100-200 g Spermophilus spilomosa - center (with S. mexicanus (upper right) and S. washingtoni (lower left)) Credit: painting by Todd Zalewski from

Rock Squirrel (Otospermophilus variegatus) FAMILY: Sciuridae Rock squirrels, with their long, bushy tails, look very much like tree squirrels, but seldom climb trees. They are most commonly found in rocky habitats canyons, cliffs, and hillsides. Occasionally a nest is found in a tree, but they usually dig burrows, choosing a place that offers a near-by lookout where they can watch for danger. Other mammals and even burrowing owls are known to use their dens if the squirrels abandon them. The rock squirrel's geographic range is large, and it is found at elevations from sea level to 2,900 m. Females produce one litter a year in places or at elevations where winter weather lasts longer, and two in warmer parts of their range. Image shows variable amounts of black coloration in species Credit: painting by Todd Zalewski from Males are larger than females. Range: 466-503 mm Range: 450-875 g

Gray-footed Chipmunk (Tamias canipes) FAMILY: Sciuridae Gray-footed chipmunks are shy and more often heard than seen. They make light "chipper" or low "chuck-chuck-chuck" calls, and when they sense danger, they scurry into deep brush, or underground, or up a tree. They are agile climbers, easily navigating rocks, cliffs, and trees. Acorns are probably their most important food during late summer and fall. They do not get tremendously fat in the fall, as do most animals that hibernate, so they probably feed on stored food. Males are slightly larger than females. Average: 237 mm Range: 210-264 mm Range: 65-75 g Credit: painting by Nancy Halliday from