PLAINS POCKET GOPHER Geomys bursarius 225-325mm, 60-121mm, 120-250g
Sparsely haired tail is about one third of body length. Inhabits deep sandy or loamy soils in most Great Plains habitats, as well as roadsides, lawns, and pastures.
TEXAS POCKET GOPHER Geomys personatus 216-360mm, 62-125mm, 156-400g
Medium-sized, drab brown gopher with soft, short pelage that is pale to whitish on the underparts. Very similar to Attwater’S, but skull has a distinct sagittal crest, and it differs in habitat, occupying only deep, sandy soils in coastal and river bottoms (red area on map).
DESERT POCKET GOPHER Geomys arenarius 218-302mm, 52-106mm, 165-254g
Distinguished from the other pocket gophers in its range by having two grooves on the upper incisors. Inhabits sandy and disturbed soils along the upper Rio Grande Valley (see yellow area on map of Texas Pocket Gopher), where it occupies desert scrub and man-made habitats.
SOUTHEASTERN POCKET GOPHER Geomys pinetis 215-324mm, 57-120mm, 135-208g
Only gopher in range. Inhabits deep, sandy soils in long-leaf pine forests. Can be a pest in orchards and lawns.
PLATE 36
WESTERN DESERT PEROGNATHUS
POCKET MICE - These small, nondescript mice are quite diverse, and sometimes hard to tell apart. All have relatively long feet, but are poor jumpers compared to their cousins the kangaroo rats. Pocket mice are typically distinguished by the amount of spiny guard hairs present (i.e., spiny or smooth) and by subtle differences in the markings on their bodies and tails. They use their fur-lined cheek pouches (also known as pockets) to carry seeds back to underground larders.
WHITE-EARED POCKET MOUSE Perognathus alticolus 130-183mm, 70-97mm, 16-24g
Rarest of the Perognathus, this species resembles Great Basin Pocket Mouse, but is restricted to isolated mountain ranges bordering the Mojave Desert. With white or yellowish hair on the ears, it also differs from San Joaquin and Little Pocket Mouse in having a lobed antitragus and a somewhat longer, darker crest on the tail. Nocturnal and secretive, little is known of their natural history, but captive animals fed on seeds and green vegetation. Found in open grassland and upland arid shrub communities between 1000 and 2000m.
SAN JOAQUIN POCKET MOUSE Perognathus inornatus 128-160mm, 63-78mm, 7-12g
Medium-sized mouse whose tail averages longer than head+body. Pelage is soft, with upperparts yellowish to pink overlaid with blackish hairs; the extent of the overlay determines the overall tone in various subspecies. Lateral line is moderately well marked, and underparts are white, with tail faintly bicolored. Posterior third of sole of hind foot is haired, and whiskers are rather short. Uses arid annual grassland, savanna, and desert scrub, with sandy washes, fine soils, and scattered vegetation below about 600m.
ARIZONA POCKET MOUSE Perognathus amplus 135-173mm, 75-88mm, 9-14g
Small pocket mouse with orangish-tan upperparts sprinkled with black to varying degrees depending on soil color, and white or pale tan underparts. Tail is longer than head and body, slightly bicolored, and lacks a terminal tuft. Although not true hibernators, they spend cool winter months in their burrow, feeding on stored seeds. Solitary and nocturnal, they forage between small shrubs or bunch-grasses in flat habitats with fine-textured soils, venturing into open areas only when the moon is dark.
LITTLE POCKET MOUSE Perognathus longimembris 110-151mm, 56-86mm, 6-11g
Smallest pocket mouse in its range, with coloration varying from gray to reddish-brown to cream dorsally, with paler buff or white hairs on undersurface. Tail relatively longer than that of San Joaquin Pocket Mouse, hind foot averages shorter than that of Arizona Pocket Mouse. The subspecies that uses sandy habitats in southern California (P. l. pacificus) was once thought extinct, but a few endangered populations were rediscovered in 1993. Uses open grassland, shrub-steppe, and coastal sage habitats, in addition to very arid desert areas.
PLATE 37
GREAT PLAINS PEROGNATHUS
OLIVE-BACKED POCKET MOUSE Perognathus fasciatus 125-142mm, 57-68mm, 8-14g
Resembles other Perognathus in having soft pelage, with no spines or bristles, and somewhat hairy soles of feet. The olive-colored back distinguishes it from the otherwise similar Plains Pocket Mouse, and a yellowish lateral stripe separates the pure white belly. The only pocket mouse occurring northward into Canada east of the Rockies, it is a resident of grassland, shrub-steppe, and desert scrub habitats of northern Great Plains and intermontane west.
PLAINS POCKET MOUSE Perognathus flavescens 117-155mm, 50-89mm, 7-16g
Small, soft-furred pocket mouse that is somewhat larger than Silky and Merriam’S Pocket Mouse, with a relatively longer tail, and smaller buffy patches behind the ears. Occupies sand dunes and other stabilized, sandy soils in the Great Plains and mountain states. Normally detected only by tracks in the sand, they can be seen at night by careful observation with good lights. Found from grassland and desert scrub up through oak woodlands and into pinyon-juniper communities.
MERRIAM’S POCKET MOUSE Perognathus merriami 95-121mm, 42-61mm, 5-9g
Tiny pocket mouse with yellowish-orange fur tinged with black on the back, and underparts that are white or pale buff and clearly separated from the darker sides. Very similar to Silky Pocket Mouse, but with a relatively longer tail, shorter, slightly coarser pelage that is paler and more yellowish, and slightly smaller buffy spots behind the ears. Common in short-grass prairies, desert scrub, and open, arid, brushy areas from sea level to 1800m.
SILKY POCKET MOUSE Perognathus flavus 100-130mm, 44-60mm, 5-10g
This is one of the smallest pocket mice, and among the smallest rodents in North America. Looks essentially identical to Merriam’S Pocket Mouse. Yellowish or reddish brown on back and sides, and white on the belly, with buffy patches behind each ear. With a diet of mostly dry seeds, they minimize water loss by foraging only on cooler, more humid nights. Occupies grassy and shrubby habitats in western and southern plains and southwestern intermontane areas.
GREAT BASIN POCKET MOUSE Perognathus parvus 160-181mm, 85-97mm, 21-31g; 160-190mm, 85-90mm, 16-29g
This is the largest Perognathus. Differs from others in having hind feet longer than 20mm, buffy hair on the inside of the ears, a lobed antitragus, an olivaceous lateral line and a bicolored tail that is is dark above and has only a slight terminal tuft. Capable of surviving on dry seeds with no free water, they will take insects and succulent vegetation when available. Occupies arid and semiarid sandy areas of sagebrush, steppe, open shrub, woodland, deserts, and dry grasslands.
PLATE 38
LIOMYS AND SPINY CHAETODIPUS
CALIFORNIA POCKET MOUSE Chaetodipus californicus 190-235mm, 103-143mm, 18-29g
Large pocket mouse with whitish spinelike stiff hairs on rump. Differs from San Diego and Spiny Pocket Mouse in larger size, longer ears (average 13mm), and relatively longer tail. Uses arid grassland and desert and coastal scrub communities as well as montane chaparral (yellow area on map).
SAN DIEGO POCKET MOUSE Chaetodipus fallax 176-200mm, 88-118mm, 17-22g
Medium-sized pocket mouse with broad region of yellowish to orangish hair on its sides that contrasts with its dark brown back. Has a number of stiff bristly hairs or spines in the rump region, but fewer than Spiny Pocket Mouse. Uses sparse, low, desert shrublands up to dense, high, coastal, sage-scrub vegetation (see red area on map of California Pocket Mouse).
NELSON’S POCKET MOUSE Chaetodipus nelsoni 182-193mm, 104-117mm, 14-18g
Drab gray, medium-sized mouse with harsh pelage and a distinctly tufted tail that is longer than the head and body. Soles of hind feet are black. Numerous and prominent spines on the rump; distal ends of the rump spines usually dark-colored dorsally; entire rump spine is pale-colored laterally. White spots below the ears. Uses rocky places in Chihuahuan desert shrub vegetation with rocky soils and cactus, creosote, sotol, and lechuguilla provide scattered cover. Avoids sandy soils.
SPINY POCKET MOUSE Chaetodipus spinatus 164-225mm, 89-128mm, 13-18g
&n
bsp; Upper pelage is drab brown and shaggy. Hairs are dark gray near base, pale tan in middle, black at tips. Lateral line is faint or absent. Underparts are buff-white. Ears are small (average 10mm) and dusky, and there is a small white spot at the base of each ear. Tail is bicolored, with a distinct crest near the tip. Spines are located mostly on the rump, but scattered spines occur as far forward as the shoulder region. Inhabits rough desert landscapes of boulders, washes, rocky slopes, coarse soil, and sparse vegetation.
ROCK POCKET MOUSE Chaetodipus intermedius 157-188mm, 84-112mm, 10-20g
Medium-sized mouse with drab grayish-brown fur on back, a pale orange-brown line on the sides, and white underneath. Comparatively harsh fur with weak “spines” on the rump, and soles of hind feet are naked to the heels. Tail is longer than the head and body and distinctly tufted at the tip. Uses rocky gulches, canyons, or boulders and rarely found on sandy or silty soils.
MEXICAN SPINY POCKET MOUSE Liomys irroratus 216-262mm, 106-138mm, 40-60g; 207-251mm, 102-131mm, 35-50g
Liomys is easily distinguished from all other pocket mice by ungrooved upper incisors. Grayish brown with white underparts, separated by buff stripe between the darker upperparts and paler underside. Fur on back has a harsh appearance caused by the mix of stiff spiny hairs and soft slender hairs. Unique spoon-shaped claw on hind foot. Uses dense brushy areas along old river terraces, or in subtropical palm forests in extreme south Texas.
PLATE 39
SMOOTH CHAETODIPUS
BAILEY’S POCKET MOUSE Chaetodipus baileyi 206-240mm, 76-140mm, 25-38g; 176-228mm, 86-125mm, 24-37g
Large, with grayish fur washed with yellow on back and rump, whitish underparts, and a long bicolored tail with a strong terminal crest. Inhabits Sonoran Desert and favors pebbly soils marking transition from sandy flats to rocky slopes (see red area on map).
BAJA CALIFORNIA POCKET MOUSE Chaetodipus rudinoris 198-223mm, 90-113mm, 30-47g
Identical in appearance to Bailey’S Pocket Mouse. This species was recently described based on strong genetic differences of populations west of the Colorado River in California and from throughout the Baja California Peninsula (see yellow area on map of Bailey’S Pocket Mouse).
LONG-TAILED POCKET MOUSE Chaetodipus formosus 172-211mm, 86-125mm, 17-25g
Medium-sized mouse with soft pelage and no stiff bristly hairs on rump. Tail is long, with a distal crest and conspicuous terminal tuft. Smaller than Bailey’S Pocket Mouse and with longer ears than Desert Pocket Mouse. Uses dry and rocky areas, such as lava beds, desert scrub, dry stream beds, and boulder-strewn hillsides in Great Basin and Mojave and Colorado deserts.
HISPID POCKET MOUSE Chaetodipus hispidus 198-223mm, 90-113mm, 30-47g
Large pocket mouse, with distinctly coarse, but not spiny, pelage. The tail is only slightly shorter than the body and distinctively bicolored with no terminal tuft. Upperparts are olive-buff and separated from white underparts by a distinct orangish-yellow stripe. Occupies grassland habitats from desert areas up through pinyon-juniper zones.
CHIHUAHAN POCKET MOUSE Chaetodipus eremicus 170-215mm, 90-115mm, 15-23g
Slightly larger and lighter in color than the very similar Desert Pocket Mouse; best distinguished by geographic range. The two were only recently recognized as distinct species from genetic evidence.
DESERT POCKET MOUSE Chaetodipus penicillatus 155-185mm, 83-110mm, 13-20g
Medium-sized pocket mouse lacking spines on rump, with yellowish-brown to yellowish-gray upper pelage and whitish underparts. Tail is long, bicolored, and strongly crested. Uses sandy soils with creosote, mesquite, or palo verde vegetation, especially along desert washes. Rocky soils tend to be avoided.
PLATE 40
KANGAROO MICE AND SMALL
FOUR-TOED KANGAROO RATS
KANGAROO MICE - With their huge hind feet and long tails, kangaroo mice are miniature versions of five-toed kangaroo rats. They differ by size, and by having a fat deposit in the tail that makes it appear wider in the middle, and with well furred soles on their hind feet. The two species of kangaroo mice are distinguished mainly by color. They are nocturnal seed eaters, and can transport food in their fur-lined cheek pouches.
DARK KANGAROO MOUSE Microdipodops megacephalus 138-177mm, 67-103mm, 10-17g
A dark-colored kangaroo mouse. Brownish, blackish, or grayish dorsal pelage distinguish it from the Pale Kangaroo Mouse. Also, the dorsal surface of the tail is darker than the body, and has a black tip. The hind foot is less than 25mm. Hair on the underparts is dark at the base and white-tipped. Uses Upper Sonoran sagebrush desert, on fine gravelly soils.
PALE KANGAROO MOUSE Microdipodops pallidus 150-173mm, 74-99mm, 10-17g
A pale pinkish-cinnamon-colored kangaroo mouse. Dorsal surface of tail is same color as the body, and lacks a dark tip. Hind foot is more than 25mm. Belly fur is pale pinkish cinnamon at the base. Uses valley bottomlands with stabilized dunes with fine sand in Upper Sonoran life zone dominated by saltbush and greasewood.
KANGAROO RATS - Aptly named rats with enormous hind feet, miniature front feet, and long tails. They have large eyes, a white racing stripe along their flanks and tails, and clearly marked dermal glands on neck between shoulder blades. Species are typically identified by their size, the number of toes on the hind feet (four or five), and characteristics of their tail. All spend the day in burrows and the night foraging for seeds, which may be transported in their fur-lined cheek pouches. May leap up to 2m in a single bound.
MERRIAM’S KANGAROO RAT Dipodomys merriami 195-282mm, 120-182mm, 33-54g
A relatively small, four-toed, slender-footed, and usually buff-colored kangaroo rat. The tail is much longer than head and body, ending with a dusky to dark tuft at the tip. Body has dorsal and ventral dusky stripes, and the underparts are white. Smaller than most four-toed kangaroo rats, with a dark (not white)- tipped tail. Different from the San Joaquin Valley Kangaroo Rat by range, body size, and color pattern on the tail. The subspecies from the San Bernardino Mountains (D. m. parvus) is Endangered. Occupies a wide variety of soil types and habitats in the Southwest.
SAN JOAQUIN VALLEY KANGAROO RAT Dipodomys nitratoides 211-253mm, 120-152mm, 40-53g
A small, four-toed kangaroo rat with yellowish-brown upperparts and white underparts. Facial crescents are dusky and meet over the bridge of the nose. Upper and lower tail stripes are sooty blackish, meeting along the terminal third, thus interrupting the white side stripes. Inner aspect of the hind legs to heel are dull fulvous, and the underparts of the thigh stripes are white. Uses alkaline plains sparsely covered with grass, or saltbush and other arid vegetation.
PLATE 41
LARGE FOUR-TOED KANGAROO RATS
BANNER-TAILED KANGAROO RAT Dipodomys spectabilis 315-349mm, 185-208mm, 110-132g; 310-345mm, 180-205mm, 98-130g
A large, spectacular four-toed kangaroo rat with a long, white-tipped tail. It is yellowish-brown above and white underneath, with a long tail covered with short hairs at the base and long hairs at the tip. Spots above the eye and behind the ear, hip stripes, forelimbs, dorsal surface and sides of hind feet, lateral tail stripes, ventral surface, and tip of the tail are pure white. Young animals are grayish on the back and slightly brighter on the sides. Active year-round, but may remain in burrows on cold or rainy nights. Lives in desert grasslands with scattered shrubs, and makes large mounds that contain extensive burrow systems.
DESERT KANGAROO RAT Dipodomys deserti 305-377mm, 180-215mm, 83-148g
Similar to D. spectabilis, but slightly paler overall and with paler, less contrasting dorsal and ventral stripes on tail. Large hind feet are covered with relatively long hairs, and have four toes. Indistinct white spot over eye, and another behind ear that extends across the shoulder to the white underparts. Indistinct white band across the hips and an indistinct darker spot at the base of the whiskers. Soles of hind feet are nearly white. Color of upper parts varies from pale fawn to grayish black, depending on subspecies. Uses loose sandy soil in the most arid areas of North America, f
rom below sea level in Death Valley to 1700m.
TEXAS KANGAROO RAT Dipodomys elator 260-345mm, 161-205mm, 65-90g
Tail is thick and long with dark stripes above and below, and white stripes on the side that end in a white tuft. Similar to Ord’S Kangaroo Rat, but that species has five toes on the hind feet and a dark terminal tail tuft. Belly is white, back is a buff color interspersed with black. Nose and eye rings are black; white thigh patches are present and meet at the base of the tail. Nocturnal and active mainly on moonless or cloudy nights. Now inhabits only three counties in central Texas; human-induced land change has driven them to local extinction in north-central Texas and southwestern Oklahoma. Uses clay and clay-loam soils with sparse vegetation, in what were originally mesquite grasslands.
CALIFORNIA KANGAROO RAT Dipodomys californicus 260-340mm, 152-217mm, 60-85g
Medium-large kangaroo rat with relatively broad face, darker upperparts and white belly. Tail has broad, dark dorsal and ventral stripes and a distinct white tuft. Typically has four toes on the hind feet, but five-toed individuals are occasionally found. Larger and darker than Merriam’S Kangaroo Rat, and smaller and darker than the Desert Kangaroo Rat. Heermann’S Kangaroo Rat is very similar, but has five toes. Burrows can be seen under boulders, bushes, and stumps in well-drained soils. Active even in rain and snow, they store only small amounts of seeds in scattered caches. Uses chaparral and other shrub, but is restricted to places where open areas are available.
Mammals of North America Page 8