Squirrels of the World

Otospermophilus variegatus 295

Otospermophilus variegatus

(Erxleben, 1777)

Rock Squirrel

description: This species has a variable pelage, as its Latin
epithet suggests. The dorsum can range from grayish mixed
with cinnamon buff to light brown to bone brown to dark
blackish brown, sometimes with the head and the shoul-
ders, or nearly the entire dorsum, being black. The head is
pinkish buff to cinnamon buff to seal brown to fuscous
black. The prominent eye ring is white to buff to tawny. The
venter is grayish white to cinnamon buff. The tail is large
and bushy, resembling that of a tree squirrel at fi rst, with a
mixed black or brown and buff y white coloration.

size: Female—Mass 450–796 g.
Male—Mass 470–875g.
Both sexes—HB 430–540 mm; T 174–263 mm.

distribution: Rock squirrels are found in Nevada east to
Colorado and southwestern Texas (USA), and south to
Puebla (México).

geographic variation: Eight subspecies are recognized.

O. v. variegatus—central Nayarit and northern San Luis Po-
tosí to Puebla and Oaxaca (México). This large form has

a blackish head, a gray dorsum, and a grizzled black and

white tail.

O. v. buckleyi—central Texas to the Rio Grande (USA). This

is a small form, with a dark dorsal pelage.

O. v. couchii—Coahuila northwest into Chihuahua, south

into San Luis Potosí, and to western Tamaulipas (México).

It is a small pale form, dominated by brown, including a

dark brown cap on the head and the shoulders.

O. v. grammurus—northern Colorado and New Mexico (USA)

south to Sonora and central Chihuahua (México), and

from southeastern California to westcentral Texas (USA).

This form is also small and pale, but it lacks the dark

coloration on the head.

O. v. robustus—eastcentral Nevada (USA). This is a larger

form. The head is brownish black, the upper back is

white, and the lower back is cinnamon buff. The eye ring

is creamy white.

O. v. rupestris—eastern Sonora and central Chihuahua to

central Nayarit and central Zacatecas (México). This

subspecies is pale; and the dorsum is dominated by

brown or buff , including a dark brown head with buff

underparts.

O. v. tularosae—southcentral New Mexico (USA). This

form lacks a black head or dorsum, and it has a tawny

posterior.

O. v. utah—northern Utah to southern Nevada and north-

western Arizona (USA). This is also a diminutive form,

but with a dark dorsum, due to an increased infusion of

a tawny color.

conservation: IUCN status—least concern. Population

trend—stable.

habitat: Rock squirrels inhabit semiarid regions with

rocky canyons, cliff s, and hillsides. They can also be found

in urban areas.

Otospermophilus variegatus. Photo courtesy Randall D. Babb.