Mammals of North America
Page 7
HOPI CHIPMUNK Tamias rufus 197-221mm, 81-95mm, 52-62g
Stripes are tawny and underside of tail is reddish. Where they overlap, the larger Colorado Chipmunk has darker stripes, and the smaller Least Chipmunk has browner stripes. Tail is carried horizontally when running. Uses rocky areas in pinyon-juniper woodlands.
UINTA CHIPMUNK Tamias umbrinus
T. u. adsitus from the Kaibab Plateau is similar to the sympatric Hopi Chipmunk, but has darker dorsal stripes. (For more details, see page 72.)
PLATE 30
SOUTHERN CALIFORNIA CHIPMUNKS
LODGEPOLE CHIPMUNK Tamias speciosus 220-222mm, 79-100mm, 51-61g; 197-229mm, 67-102mm, 55-69g
A brightly colored chipmunk with broad, pure white outer dorsal stripes. Outermost dark stripes are poorly distinguished. Underside of tail has a black tip. Sides are reddish brown. Top of head and rump are grayish. Winter pelage is grayer overall, with browner dark dorsal stripes. Larger than the Yellow-pine Chipmunk, with less distinct outermost dark stripes. Smaller than the Long-eared Chipmunk, with relatively smaller ears. Climbs trees more than most chipmunks. Common in open coniferous forests.
MERRIAM’S CHIPMUNK Tamias merriami 240-255mm, 100-115mm, 70-80g
Large chipmunk with a bushy tail. Contrasting dorsal stripes are light gray and brown. Duller, but very similar to California Chipmunk; genital bones may be needed for certain ID. Distinguished from Townsend’S Chipmunk by having gray (not brown) cheeks. Edging on tail is buff-colored, not white like in the Long-eared Chipmunk. Darker on coast (see page 78). Calls with “chips” and a trill from elevated perches in pine and oak forests.
CALIFORNIA CHIPMUNK Tamias obscurus 200-250mm, 70-120mm, 60-84g
Large chipmunk with a bushy tail. Head is grayish on top and striped in white on the sides. Back has brown and gray stripes. Striping is less distinguished in winter pelage. Overlaps slightly in range with the very similar Merriam’S Chipmunk; genital bones needed for certain ID. Stands on hind feet to give “chip” vocalization. Common in sandy and rocky areas with sparse pinyon pine, juniper, and scrub oak vegetation (yellow area on map).
PALMER’S CHIPMUNK Tamias palmeri 210-223mm, 87-101mm, 50-69g
A small chipmunk from the Spring Mountains of southwest Nevada. Has only three (not the usual five) dark stripes on back. The center pair of pale stripes is grayish, the outer pair and belly are creamy white. Colors are more muted in the winter. Only the larger Panamint Chipmunk overlaps in range. These two are also distinguished by the grayer shoulders of Palmer’S Chipmunk. May be conspecific with T. umbrinus; genital bones are shown for certain ID. Emits chippering, chip, and chuck calls along cliffs. Found in rocky coniferous habitat above 2000m elevation (see red area on map of California Chipmunk).
PANAMINT CHIPMUNK Tamias panamintinus 230-239mm, 85-100mm, 74-89g; 230-245mm, 90-101mm, 81-105g
A pale-colored chipmunk with a grayish head, rump, and thighs. Back has contrasting pale and brown stripes. The center pair of pale stripes are grayish, the outer pair are creamy white. Head is somewhat flattened. Colors are brightest in spring, dullest in late winter. The subspecies from the Kingston mountains is smaller and darker. Redder than the Least Chipmunk. Has paler facial stripes and less contrasting dorsal stripes than Palmer’S, Lodgepole, Yellow-pine, and Uinta chipmunks. Genital bones are shown for certain ID. Call rate lower (eight syllables) than Palmer’S Chipmunk. Lives in pinyon pine and juniper habitat at high elevations (1500-2600m).
PLATE 31
NORTHWESTERN COASTAL CHIPMUNKS
CONFUSING CALIFORNIA CHIPMUNKS - These species are difficult to tell apart. Four (T. ochrogenys, senex, siskiyou, and townsendii) were once lumped together in the Tamias townsendii species group. Geographic range and color patterns are useful, but genital bones (from the skeleton) and voice are the only 100% reliable methods to distinguish all species. To aid in comparisons, we have placed the duller coastal morphs and the brighter inland morphs on different pages.
TOWNSEND’S CHIPMUNK Tamias townsendii 230-280mm, 95-120mm, 90-118g
The only chipmunk on the coast in its range, has indistinct dorsal stripes and brownish cheeks. The coastal form is dark brownish or olivaceous in color, with indistinct pale and dark lines on the back. Winter animals darker with buff-white stripes while summer animals are brighter. See next plate for details on the brighter inland form. Call has two to three syllables per chip. Lives in forests and recently cleared areas.
YELLOW-CHEEKED CHIPMUNK Tamias ochrogenys 233-297mm, 97-130mm, 60-118g
Has a less bushy tail, a darker back, and more distinct dorsal stripes than other townsendii-group chipmunks. The center stripe on back is the largest. Tail is dark rufous to bright orange ventrally and the same color as the rest of the body dorsally. Winter pelage is long, silky, dense and more dull-colored with dark tawny olive to blue-gray tones. Vocalizes with a unique sounding low-frequency two-syllable “chip.” Thrives in dark, moist redwood forests.
SONOMA CHIPMUNK Tamias sonomae 220-264mm, 100-126mm, 63-77g
A brightly colored chipmunk with a bushy tail that is slightly edged in buff. The outer pair of pale dorsal stripes are dull whitish washed with cinnamon-buff molting to grayish in the winter; the dark dorsal stripes are black (rarely fuscous). Dorsally, tail is blackish mixed with tawny. Ventrally, tail is tawny, bordered with black and tipped with a small amount of pale buff. Call a low, labored, blunt “pok” sound. Lives in chaparral, small brushy clearings in forests, and streamside thickets. (See page 80 for the inland forms and genital bones.)
SHADOW CHIPMUNK Tamias senex 223-281mm, 94-122mm, 90-120g
A dark olive chipmunk with one pair of pale dorsal stripes brighter than the other in the summer. Tail is relatively thin. The dark dorsal stripes scarcely reach the rump. Inland populations are brighter-colored (see page 80). Calls with a rapid series of three to four syllables, sometimes stretching to 10 syllables. Primarily arboreal in humid coastal redwood forests (dull morph), and more arid inland forests.
MERRIAM’S CHIPMUNK Tamias merriami
Large chipmunk with a bushy tail. Distinguished from Townsend’S Chipmunk by having gray (not brown) cheeks. Edging on tail is buff-colored, not white. Brighter inland (see page 76 for more details). Calls with “chips” from elevated perches in pine and oak forests.
PLATE 32
NORTHWESTERN INLAND CHIPMUNKS
TOWNSEND’S CHIPMUNK Tamias townsendii
Larger than the overlapping inland chipmunks (T. amoenus and minimus). Paler than the coastal townsendii subspecies, with more reddish or orangish color. The pale body stripes fade out both near the head and rump, becoming more or less obscured by tawny or grayish shades. (See also the coastal chipmunks, page 78.) Lives in coniferous forest and brush.
SHADOW CHIPMUNK Tamias senex
Orangish, with a gray rump and bright white outer dorsal stripe. The sides are clay color to tawny; rump and thighs are gray; underparts are creamy white. Well-defined dark body stripes are brownish black; middle stripe is darkest. The middle pair of pale, back stripes are grayish white to cinnamon; outer pair are brighter, but fade to duller toward the rump. More details on the previous plate. Uses humid coastal forests (dark morph, see page 78) and arid inland forests (brighter morph).
SONOMA CHIPMUNK Tamias sonomae
A brightly colored chipmunk with a pale-edged tail. Back is cinnamon-buff with blackish dorsal stripes. The medial pale stripes are smoke gray and the outer pair is creamy white. The rump and thighs are gray mixed with cinnamon-buff. Underparts are creamy white. Dorsally, the tail is black, sprinkled with pale buff. Ventrally the tail is tawny and is bordered with fuscous black and edged with buff in the summer and grayish white in the winter. Lives in chaparral, small brushy clearings in forests, and streamside thickets. (See page 78 for more details.)
ALPINE CHIPMUNK Tamias alpinus 166-184mm, 63-81mm, 27-45g
Our smallest chipmunk has a short, broad tail that is frosted above and has black at the tip. Tail is shorter and flatter th
an T. minimus with larger ears and paler dorsal coloration. Smaller than T. amoenus, with duller coloration, more grayish hind feet, and tail with more black at tip. Winter animals are grayer above, with less tawny sides. Lives in rock-bordered alpine meadows and on talus slopes near timberline of the highest peaks of the Sierra Nevada.
LONG-EARED CHIPMUNK Tamias quadrimaculatus 230-239mm, 85-100mm, 74-89g; 230-345mm, 90-101mm, 81-105g
A reddish chipmunk with distinct stripes and large, slightly tufted ears. On face, pale and dark stripes contrast strongly, and the pale malar stripe connects with the large creamy-white ear patches. The top of the tail is blackish brown overlaid with grayish white; the undertail is tawny brown, bordered with mixed dark and pale gray fur. Winter animals have a grayish-brown top of the head, rump, and thighs. Summer pelage has less gray and more cinnamon in the upperparts. Call a sharp “whssst” or “pssst.” Forages on ground or in bushes of chaparral and forests.
SISKIYOU CHIPMUNK Tamias siskiyou 250-268mm, 98-117mm, 65-85g
A large, dull-colored chipmunk with a small range. Outer lateral stripes on dorsum are grayish or brownish and paler than the inner stripes. Yellow-pine Chipmunk, the only sympatric chipmunk, is much smaller with lateral dorsal stripes that are white. Vocalizes with an intense one-syllable call that starts at a low pitch, rises, and then falls again. Uses moist coniferous forests and second-growth forests usually dominated by Douglas fir.
PLATE 33
NORTHERN THOMOMYS
GOPHERS - These small rodents are well adapted to life underground with their reduced eyes and ears and enlarged front feet and claws. They also dig with their incisors, and can close their lips around these front teeth, allowing them to continue chewing a new hole without getting a mouthful of dirt. Burrow systems are conspicuous, while the animals themselves are rarely seen. They can transport food in their fur-lined cheek pouches. The three North American genera are distinct by having 0 (Thomomys), 1 (Cratogeomys) or 2 (Geomys) grooves in their upper incisors. All of the Thomomys on this plate have skulls lacking a sphenoidal fissure (see page 85).
CAMAS POCKET GOPHER Thomomys bulbivorus 220-328mm, 56-99mm, 375-543g
Largest of the Thomomys, with a very restricted range. Dull sooty brown on the back, and dark grayish brown below, often with an irregular-shaped white patch on the throat. The ears and nose are blackish. Tips of the upper incisors angle distinctly forward in the front of the mouth, rather than pointing downward, giving the animal a bucktoothed appearance. Restricted to the Willamette Valley, and nearby tributaries in Oregon.
NORTHERN POCKET GOPHER Thomomys talpoides 165-260mm, 40-75mm, 60-160g
A widespread and variable gopher with dark patches behind the ear. Color can be brown or grayish brown to yellow-brown. A small Thomomys, with short soft fur that is less glossy than in most other species. Often has white markings under chin. Lack of a sphenoidal fissure is a feature in the skull, which separates it from other potentially overlapping gophers (see skull illustrations on page 85). This species is associated with “Mima Mounds,” mounded areas up to 2m high and 20m in diameter in grassland areas. The larger the mounds, the more gophers using an area. Uses a variety of open habitat types, even forests with widely spaced trees.
WYOMING POCKET GOPHER Thomomys clusius 161-184mm, 50-70mm, 46-88g
Small gopher with pale yellow color, lack of dark-colored patches behind and below ears, and presence of a fringe of white hair on ears. Often associated with loose gravelly soil and greasewood habitats. Extremely limited distribution (red area on map), where it is the smallest and palest gopher.
IDAHO POCKET GOPHER Thomomys idahoensis 167-203mm, 40-70mm, 46-88g
Very small gopher that is pale yellowish in Idaho and Montana, but darker brown in Wyoming (see yellow area on map of Wyoming Pocket Gopher). Reddish individuals are rare. Differs from others in its range in lacking dark ear patches and contrasting grayish cheeks. Lacks the white ear fringe of the neighboring Wyoming Pocket Gopher. Seems to favor shallow and stony soils.
WESTERN POCKET GOPHER Thomomys mazama 191-233mm, 53-78mm, 75-125g
Richly colored gopher with pale to dark reddish-brown back and gray underparts tipped with buff. Some individuals on dark soils are darker colored. Has long ears for a gopher. Below the ear is a black patch of fur five to six times the area of the ear. Uses deep humic volcanic soils of alpine meadows and small glacial prairies.
PLATE 34
CRATOGEOMYS AND SOUTHERN THOMOMYS
BOTTA’S POCKET GOPHER Thomomys bottae 170-280mm, 62-92mm, 110-250g; 150-240mm, 55-73mm, 80-160g
One of the world’S most variable small mammals, usually has a unique purple tinge to the flanks. Ranges from dark blackish brown through various shades of reddish and yellowish browns, pale grays, and yellows, to nearly white. Ventral coloration usually mirrors that of back. Patches of white on throat, chest, or abdomen are not uncommon. Body color is tied to soil color. Dark patches behind ear are most evident in lightly colored individuals. Skull has an obvious sphenoidal fissure. Typically larger than the Southern Pocket Gopher and smaller than Townsend’S Pocket Gopher. Lives in virtually any friable soil, from rich valleys to rocky montane slopes and desert outwash areas. Wide range of habitat types from desert up to coniferous forests, but mainly in open areas where soils are deep enough for burrows (meadows, stream sides, etc.).
SOUTHERN POCKET GOPHER Thomomys umbrinus 210-250mm, 65-80mm, 110-175g; 180-230mm, 55-70mm, 80-120g
Typically has a unique darkened, bluish mid-dorsal band. Color varies from dark, rich reddish brown to blackish brown. Skull has a sphenoidal fissure. Only has three pairs of pectoral mammae, as opposed to four pairs normally found in Botta’S Pocket Gopher. Known in United States only from Pajarito, Santa Rita, Patagonia, and Huachuca mountains in Arizona, and Animas Mountains in New Mexico. Inhabits desert scrub and grasslands through intermediate elevation oak and pine-oak woodlands, to grassy meadows in high elevation pine and fir forests.
TOWNSEND’S POCKET GOPHER Thomomys townsendii 232-315mm, 60-99mm, 201-417g; 226-287mm, 58-92mm, 122-308g
Larger than other Great Basin pocket gophers, nose is usually darkened. Color varies from pale grayish tan through cinnamon to very dark brown. In some areas a white blaze on the top of the head is fairly common. The nose is sooty black, gray, or dark brown, and most animals also have a black spot behind each ear. Typically, the tops of the feet and tail are white and there is a white chin patch. Skull has a sphenoidal fissure. Uses deep, moist soils of river valleys and prehistoric lakebeds.
MOUNTAIN POCKET GOPHER Thomomys monticola 190-227mm, 55-95mm, 75-105g
A uniformly brown gopher with relatively large and pointed (not rounded) ears. Behind the ears there is a large black patch about three times the size of the ear. There is no sphenoidal fissure in the skull. The snout is darker than the face. Favors montane meadows, pastures, and rocky slopes of pine, fir, and spruce in the Sierra Nevadas.
YELLOW-FACED POCKET GOPHER Cratogeomys castanops 220-315mm, 60-95mm, 385-410g; 225-290g
Large eyes and a single groove in the upper incisors distinguish this species from all other pocket gophers. The upperparts vary from pale yellowish-buff to dark reddish-brown, and the underparts are whitish to bright orange. All hairs are grayish at the base, usually with slightly darker hues on the back. It uses deep sandy soil with few rocks, in both grasslands and more arid habitats.
PLATE 35
GEOMYS
TRICKY TEXAS GOPHERS - The first five species of long-tailed gophers are virtually indistinguishable by appearance, and were originally identified by genetic differences. They can be distinguished from other overlapping gophers by size and by skull characters (all lack sagittal crest and knob on zygoma).
BAIRD’S POCKET GOPHER Geomys breviceps 192-222mm, 54-67mm, 78-150g
Limited to sandy soils, or sandy loams in prairie grasslands and oak savannas (yellow area on map).
ATTWATER’S POCKET GOPHER Geomys attwateri 192-235mm, 51-70mm, 102-170g
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br /> Limited range in Texas (see red area on map of Baird’S Pocket Gopher), where it occupies friable soils in grasslands.
KNOX JONES’S POCKET GOPHER Geomys knoxjonesi 203-282mm, 57-104mm, 160-185g
Restricted to areas of western Texas and eastern New Mexico with deep, sandy soils (yellow area on map). Favors yucca grasslands, although can now be found along grassy roadsides, and in lawns and pastures.
CENTRAL TEXAS POCKET GOPHER Geomys texensis 185-272mm, 51-80mm, 125-165g
Smaller than nearby Attwater’S, Plains, and Texas Pocket Gophers. Favors deep brown loamy sands or gravelly sandy loams in live-oak, mesquite, ash, and juniper habitats (see red area on map of Knox Jones’S).