Squirrels of the World

Otospermophilus beecheyi 293

fornia rock squirrel is considered a habitat specialist that is
subject to considerable habitat fragmentation.

natural history: This species has received very little at-
tention. No information is available on its behavior, popula-
tion biology, or general ecology. O. atricapillus has been col-
lected during winter months and is thus considered either
active throughout the year or as having a limited period of
torpor. This species may be preyed on by coyotes (Canis la-
trans), and it is host to at least one species of sucking louse
(Enderleinellus orborni).

general references: Álvarez-Castañeda, Arnaud, et al.
1996; Álvarez-Castañeda, Castro-Arellano, and Lacher 2008;
Castro Arellano and Ceballos 2005; Durden and Musser
1994a, 1994b; Goodwin 2009; Grajales et al. 2003; R. G. Har-
rison et al. 2003; Helgen et al. 2009.

Otospermophilus beecheyi

(Richardson, 1829)

California Ground Squirrel

description: O. beecheyi has a grayish brown back speck-
led with white spots, and sometimes a grayish white collar
on the back, the neck, and the sides. The venter is yellowish
white to light brown; the tail is bushy; and white eye rings
are usually present. This species shows sexual dimorphism

(larger males) and temporal, spatial, and latitudinal varia-

tion in body size.

size: Female—HB 254.3 mm; T 171.0 mm; Mass 508.5 g.

Male—HB 273.2 mm; T 181.7 mm; Mass 621.3 g.

Sex not stated—HB 246.9 mm; T 179.0 mm; Mass 599.5 g.

distribution: The California ground squirrel ranges from

western Washington through most of California (USA) to

Baja California, México.

geographic variation: Eight subspecies are recognized.

O. b. beecheyi—westcentral California (USA). See description

above.

O. b. douglasii—Washington and the Columbia River south

to San Francisco Bay, California (USA). The shoulder

patch is dark, ranging from brown to black.

O. b. fi sheri—California, from Madera County south to the

southern San Joaquin Valley and east to the Panamint

Mountains (USA), and extending farther south to Baja

California (México). The general color is paler, with more

silvery gray on the sides of the neck and the shoulders.

O. b. nesioticus—Santa Catalina Island and the Santa Barbara

Islands, California (USA). The general color is darker, with

less yellowish brown. The top of the head and the ears are

black. The sides of the neck are gray, extending into a

stripe of gray along the shoulders. A patch between the

shoulders is mixed black and tawny ochraceous.

O. b. nudipes—Sierra Juarez, Baja California (México). Its

general color is darker than O. b. rupinarum, and it has a

silvery white mantle.

O. b. parvulus—Argus Mountains, California (USA). This

form is similar to O. b. fi sheri, but O. b. parvulus is smaller.

It is also paler than the typical O. b. beecheyi.

O. b. rupinarum—Catavina, Baja California (México). It is

similar to O. b. nudipes, but O. b. rupinarum is grayer on

the dorsum, with many light spots. The venter is very

pale whitish.

O. b. sierrae—Lake Tahoe, in California and Nevada (USA).

This subspecies is similar to O. b. beecheyi, but O. b. sier-

rae is less buff y in general, with the sides of the head

grayer; the venter is paler whitish.

conservation: IUCN status—least concern. Population

trend—stable.

habitat: O. beecheyi occurs in a variety of habitats, includ-

ing meadows, grasslands, chaparral, successional stands,

and agricultural lands. It is often found along roadsides and

in disturbed areas.