Rodents (Order Rodentia)

Marmots, Ground Squirrels, and Chipmunks (Family Sciuridae)

Yellow-bellied Marmot,Marmota flaviventris. (Fig. 12.7) Head and body 14–19 in (36–48 cm); tail 4.5–9 in (11–23 cm); weight 5–10 lb (2.3–4.6 kg); upper surface yellowish brown with white-tipped hairs, underside yellow; white band below eyes. Marmots occur from 9,000 ft (2,744 m) to 13,500 ft (4,115 m) elevation. They inhabit rocky terrain near vegetated areas, preferably alpine meadows bordering talus slopes. White Mountain marmots hibernate from September to late April. During the active season they forage on grasses, sedges, and forbs, storing body fat for overwinter sustenance. When not feeding, marmots usually bask in the sun on rocks, which also serve as refuges from predators. Sharp alarm whistles are given when a predator, such as a Coyote or Golden Eagle, is suspected to be nearby. Yellow-bellied Marmots live in colonies of related adult females and their young. Juveniles are born in early June and first emerge aboveground in early July. Litter size averages five to six.

Golden-mantled Ground Squirrel,Spermophilus lateralis. (Fig. 12.8) Head and body 6–8 in (15–20 cm), tail 2.5–4.8 in (6–12 cm); head and shoulders golden; one white stripe bordered by two long black stripes on each side of back. Golden-

Figure 12.7
Yellow-bellied Marmot.

Figure 12.8
Golden-mantled Ground Squirrel.

mantled Ground Squirrels occur from about 7,000 ft (2,130 m) to 14,000 ft (4,270 m) in most habitats within this range. Their diet consists primarily of seeds, nuts, and fruits. In winter these hibernators subsist on body fat stored during the summer months, and may also eat food cached in their burrows during periodic arousals. Hawks, eagles, Coyotes, and weasels are their main predators. Young appear above-ground in July; litter size is two to six.

Antelope Ground Squirrel,Ammospermophilus leucurus. (Fig. 12.9) Head and body 5.5–6.5 in (14–16.5 cm), tail 2–3 in (5–7.6 cm); grayish brown with one stripe on each side and no dark stripes; tail usually held closely over the back while running, exposing white underside. This fast-moving desert ground squirrel occurs from the floor of Owens Valley to 8,300 ft (2,530 m) in the White Mountains. Whereas most other rodents that live in such hot and arid environments are nocturnal, the Antelope Ground Squirrel is day-active and avoids overheating by allowing its body temperature to rise up to 109°F (43°C) — higher than that of any other nonsweating mammal. Once it reaches this high body temperature, the Antelope Ground Squirrel cools itself by going into an underground burrow, where it dissipates the excess body heat. Highly efficient kidneys and evaporative cooling by fur licking also help this rodent maintain body temperature and water balance in a hot environment. Its diet consists mainly of seeds and fruits, but some animal matter is also eaten. Litter size is six to eight.

Figure 12.9
Antelope Ground Squirrel.

Chipmunks,Eutamias . The chipmunk has alternate dark and light stripes on the body that extend to the head, in contrast to ground squirrels, which lack head stripes. Sides are yellowish to reddish brown, with the undersurface whitish. There are three species of chipmunks in the White Mountains. Identification of individual species requires careful observation of physical characteristics as well as locality and habitat type.

Sagebrush Chipmunk, E. minimus . Head and body 3.7–4.5 in (9.3–11.4 cm), tail 3–4.5 in (7.6–11.4 cm); short, grayish fur with contrasting stripes — dorsal stripe black, outer light stripe white, all stripes extending to base of tail; tail held vertically when moving, yellowish underneath. Occurs from 7,000 ft (2,134 m) to at least 11,800 ft (3,598 m) in sagebrush, mixed Pinyon-juniper Woodland, and Alpine Fell-field habitats.

Panamint Chipmunk, E. panamintinus . Head and body 4.5–4.7 in (11.4–11.9 cm), tail 3.5–4 in (8.9–10.2 cm); crown of head noticeably gray; shoulders and back reddish; outer dark stripes, below the outer white stripes, are inconspicuous; other dorsal dark stripes are reddish or grayish. Occurs above 5,900 ft (1,800 m) to 9,500 ft (2,900 m) in Pinyon-juniper Woodland.

Uinta Chipmunk, E. umbrinus . (Fig. 12.10) Head and body 4.5–5 in (11.4–12.7 cm), tail 3.5–4.6 in (8.9–11.7 cm); back of neck and crown grayish; outer light stripes pure white, dorsal stripes well demarcated, outer dark stripes indistinct. Distribution restricted in the White Mountains to the Bristlecone Pine Forest, 9,500–11,500 ft (2,900–3,510 m).

Chipmunks store large caches of seeds and fruits in their burrows for sustenance during the winter. They may hibernate in some years, but their periods of torpor are not as predictable as those of ground squirrels and marmots. Chipmunks also eat insects and fungi and are themselves eaten by hawks, weasels, Coyotes, snakes, and other carnivores. Litter size is three to six, and young are generally active aboveground by June or July.

Figure 12.10
Uinta Chipmunk.

Pocket Gophers (Family Geomyidae)

Pocket Gophers,Thomomys. Head and body 4.8–7 in (12–18 cm), tail 2–3.8 in (5–9.5 cm); yellowish brown-gray fur; head small and flattened; neck short; shoulders and forearms broad and muscular; eyes small; fur-lined internal cheek pouches on either side of mouth. Two species of pocket gophers inhabit the White Mountains: the Northern Pocket Gopher (T. talpoides ), which ranges from the floor of Owens Valley to 8,200 ft (2,500 m); and the Valley Pocket Gopher (T. bottae ) (Fig. 12.11), occurring from the valley floor to about 10,500 ft (3,200 m). Preferred habitat for both is around meadows in soft soil, rarely in densely wooded or rocky areas. Pocket Gophers are strictly herbivorous, feeding on a wide range of foods including roots and succulent vegetation. The long, curved claws and chisel-like incisors are used to excavate tunnels below the ground surface. Gopher activity is apparent from the characteristic fan-shaped pile of soil marked by concentric rings where soil has been pushed up from below. Predators include owls, hawks, Badgers, Coyotes, and weasels. Young are born in the spring, and number three to six to a litter.

Pocket Mice, and Kangaroo Rats and Mice (Family Heteromyidae)

Pocket Mice,Perognathus. Head and body 2.5–4.8 in (6.4–12.2 cm), tail 3.2–4.8 in (8.1–12.2 cm); upper surface yellowish brown, white below; ears small; an external fur-lined pouch at each side of mouth; forelegs and feet small, hind feet and tail long; hind feet without hair. Two species of these nocturnal rodents are present in the White Mountains. The Long-tailed Pocket Mouse (P. formosus ) (Fig. 12.12) ranges up to 7,100 ft (2,165 m) and is common in rocky areas. It is distinguished by its bicolored tail that is heavily crested with a tuft at its end and darker than the rest of the body. The Great Basin Pocket Mouse (P. parvus ) occurs in sagebrush and Pinyon-juniper Woodland up to about 8,300 ft (2,530 m). Pocket Mice are quadrupedal except for isolated bipedal leaps away from danger. Their cheek pouches serve to transport seeds to underground food caches. During times of extreme weather conditions or food scarcity, Pocket Mice go into torpor, (i.e., lower their body temperature, heart

Figure 12.11
Valley Pocket Gopher.

Figure 12.12
Long-tailed Pocket Mouse.

rate, and metabolic rate to conserve energy). Their main predators include owls and Coyotes. Litter size is two to six, and young are born in June or July.

Kangaroo Rats,Dipodomys. Head and body 4–5 in (10.2–12.7 cm), tail 5–7.3 in (12.7–18.5 cm); body yellowish brown above, whitish below; ears small; external cheek pouches; hind legs large; tail always longer than head and body, has dark dorsal and ventral longitudinal bands with lateral longitudinal stripes and is tufted with long hairs. The White Mountains contain three species of kangaroo rats: Ord's Kangaroo Rat (D. ordii ) (Fig. 12.13) ranges up to 6,500 ft (1,982 m); Merriam's Kangaroo Rat (D. merriami ) occurs up to 7,200 ft (2,195 m); and the largest of the three species, the Great Basin Kangaroo Rat (D. microps) , has been reported up to 7,100 ft (2,165 m). Kangroo Rats are bipedal, foraging at night mostly on seeds. The Great Basin Kangroo Rat is also known as Chisel-tooth, because it uses its flattened incisors to shave off the salty outer layers of saltbush (Atriplex ) leaves before consumption. Kangaroo Rats are noted for their highly developed water conservation ability. Water is derived solely from oxidation of carbohydrates, fats, and protein and is conserved by kidneys that are able to dispose of wastes with an extremely small output of water. Their large auditory chambers help to alert them to attack by owls and Coyotes, their main predators.

Figure 12.13
Ord's Kangaroo Rat.

Mice, Rats, Lemmings, and Voles (Family Cricetidae)

Western Harvest Mouse,Reithrodontomys megalotis. Head and body 2.8–3 in (7.1–7.6 cm), tail 2.3–3.2 in (5.8–8.1 cm); upper parts and sides buffy, underparts grayish brown; tail indistinctly bicolored; no external cheek pouches. Western Harvest Mice have been reported up to 6,700 ft (2,040 m) in the White Mountains, inhabiting damp grassy meadows and marshy areas, but they may occur in other habitats during population peaks. They eat mainly seeds and fruits, with some insects, and they are preyed upon by owls, snakes, and a number of mammalian predators. They commonly use the runways of meadow mice (Microtus spp.) during their nightly foraging periods. Litters are produced several times per year and average four to six young.

Deer Mice,Peromyscus. There are three species of Deer Mice present in the White Mountains. They can be distinguished from other mice by several characteristics, including their large, membranous ears, lack of external cheek pouches, and a tail exceeding 70% of the head and body length. Their diets consist of seeds, fruits, and insects, particularly butterfly and moth larvae. They are active year-round and store caches of food for winter consumption. Deer Mice are preyed upon by many avian and mammalian predators.

Pinyon Mouse, P. truei . Head and body 3.6–4 in (9.1–10.2 cm), tail 3.4–4.8 in (8.6–12.2 cm); brown to dark brown above, creamy white underneath; feet whitish; tail bicolored, whitish below, length exceeds 90% of head and body length; ears very large. Pinyon Mice have been documented up to 9,500 ft (2,896 m) and are common in the Pinyon-juniper Woodland, where they feed on juniper berries and Pinyon Pine nuts. Much of their time is spent in trees.

Deer Mouse, P. maniculatis . (Fig. 12.14) Head and body 2.8–4 in (7.1–10.2 cm), tail 2–5 in (5–12.7 cm); yellowish brown to grayish above, pure white below; feet white; bicolored tail usually less than 90% of head and body length. The Deer Mouse, probably the most common mammal in North America, has the greatest elevational range of any mammal in California. The same subspecies of Deer Mouse that lives on the floor of Death Valley also occurs on White Mountain Peak (14,246 ft, 4,340 m). Deer Mice live in nearly all habitat types.

Figure 12.14
Deer Mouse.

Canyon Mouse, P. crinitus . Head and body 3–3.4 in (7.6–8.6 cm), tail 3.5–4.3 in (8.9–10.9 cm). Fur long and soft, pale yellowish buff above and creamy white below; long hairs on tip of tail; feet white; tail usually longer than the head and body, with a broad, light brown dorsal stripe, creamy white below. Canyon Mice frequent rocky areas up to 8,250 ft (2,515 m) in the White Mountains.

Southern Grasshopper Mouse,Onychomys torridus. Head and body 3.5–4 in (8.9–10.2 cm), tail 1.6–2 in (4–5 cm); light cinnamon above, white below. The Grasshopper Mouse has been found up to 5,000 ft (1,524 m), most commonly in canyons. The diet is 90% animal matter, most of which is arthropods. These nocturnal rodents emit high–pitched calls and usually nest in burrows dug by other mammals. Predators include snakes, weasels, owls, Bobcats, and other carnivores.

Wood Rats,Neotoma. The scaly tail of the largely nocturnal Wood Rat is covered by overlying hairs. Wood Rats eat mostly vegetation and are preyed upon by Coyotes, foxes, owls and large snakes. Litter size is three to four, and young are born in the spring. There are two species of wood rats present in the White Mountains.

Desert Wood Rat, N. lepida . Head and body 5.8–7 in (14.7–17.8 cm), tail 4.3–6.4 in (10.9–16.3 cm); fur grayish, mixed with black hairs above, underparts white or buffy; tail hairs short. Also known as the Pack Rat, this species occurs up to 8,000 ft (2,440 m) in Sagebrush Scrub and Pinyon-juniper Woodland and frequents rocky areas in these regions. It uses cactus for water and nesting material.

Bushy-tailed Wood Rat, N. cinerea . (Fig. 12.15) Head and body 7–9.4 in (17.8–23.9 cm), tail 5.2–7.4 in (13.2–18.8 cm); fur cinnamon brown to buffy, some tipped with black above; white or grayish below; tail with hairs over 2 cm long. Bushy-tailed Wood Rats have been recorded up to 10,300 ft (3,140 m) in the White Mountains; however, a single individual was collected from the summit hut on White Mountain Peak (14,246 ft, 4,340 m) during the summer of 1983. Whether this is an accurate representation of their usual range in these mountains is uncertain.

Figure 12.15
Bushy-tailed Wood Rat.

Sagebrush Vole,Lagurus curtatus. Head and body 3.8–4.5 in (9.6–11.4 cm), tail 0.6–1.1 in (1.5–2.8 cm); fur long and fine, light grayish above and almost white below. Sagebrush Voles occur up to 12,500 ft (3,810 m) in Sagebrush Scrub and Pinyon-juniper Woodland. Similar to meadow voles, they are active both day and night. They feed on nearly anything green and do not require additional drinking water. This species is endemic to the Great Basin. Litters average five young.

Meadow voles,Microtus. There are three species of meadow mice or voles in the White Mountains. All are active both day and night and are preyed upon by hawks, owls, falcons, Coyotes, weasels, and snakes. They feed on stems and leaves of forbs and grasses. The litter size usually ranges from five to eight young.

Montane Vole, M. montanus . Head and body 4–5.5 in. (10.2–14 cm), tail 1.2–2.6 in (3–6.6 cm); fur dark brown, some reddish tinged; undersurface dark gray; tail usually less than one-third of total body length, nearly unicolored. The Montane Vole occurs up to at least 12,500 ft (3,810 m), commonly in alpine meadows or other high-elevation grassy areas. It builds conspicuous runways through grasses and sedges, and it tunnels beneath the snow during the winter. It feeds chiefly on succulent stems and leaves of forbs, rarely grasses.

Long-tailed Meadow Vole, M. longicaudus . (Fig. 12.16) Head and body 4.5–5.3 in (11.4–13.5 cm), tail 2–3.5 in (5–8.9 cm); dorsal band of reddish brown fur with grayish sides and bluish gray underparts; tail usually more than one-third of total body length and more or less bicolored. The Long-tailed Meadow Vole is common along streams and in wet meadows in higher elevations up to 11,500 ft (3,510 m). Unlike the Montane Vole, it does not construct extensive runways.

California Meadow Vole, M. californicus . Head and body 4.6–5.7 in (11.7–14.5 cm), tail 1.6–2.8 in (4–7.1 cm); buffy or dark brown above, commonly with a reddish tinge on the middle of the back; undersurface blue-gray to white; ears project well above fur. This species has been recorded up to 4,500 ft (1,370 m) in Silver Canyon, but occurs mostly along the Owens River.

Figure 12.16
Long-tailed Meadow Vole.

Beavers (Family Castoridae)

Beaver,Castor canadensis. Beavers were introduced to the east side of the White Mountains in the Cottonwood Creek area about 1950. Environmental damage caused by beavers led to an apparently successful program to remove them in the mid-1970s. Remnants of their dams may still be visible on some creeks.

Porcupines (Family Erethizontidae)

Porcupine,Erethizon dorsatum. (Fig. 12.17) Head and body 18–22 in (46–56 cm), tail 7–9 in (18–23 cm); weight usually 9–15 lb (4–7 kg); yellowish to blackish above; stiff quills and spines, especially on rump and tail. Porcupines exhibit a distinct habitat and diet shift with season. In winter they inhabit wooded areas, where they consume tree bark; a variety of habitats and foods are used in summer. During the summer they may range up to 13,500 ft (4,115 m), where they forage on flowers and leaves of alpine forbs. The spines of these slow-moving rodents are actually modified hairs that are loosely attached to the body. When under attack by a Mountain Lion, Bobcat, or Coyote, a slap of the tail is enough to drive the quills into the predator.