Squirrels of the World

Urocitellus townsendii 363

response to aerial predators. The number of callers in a
population indicates the severity of the potential threat.
Richardson’s ground squirrels will eat cereal grains; thus
they are considered a pest and are poisoned in some agri-
cultural areas.

general references: Dobson, Michener, et al. 2007; Mi-
chener and Koeppl 1985; Michener and McLean 1996; Swen-
son 1981.

Urocitellus townsendii (Bachman, 1839)

Townsend’s Ground Squirrel

description: Townsend’s ground squirrels have a uniform
pale smoke gray back suff used with pinkish buff. The cheeks
and the hind limbs are washed with red to rust. The venter is
white to cream, washed with pinkish buff. The tail is grizzled
smoke gray above, with a cinnamon cast to the underside.

size: Female—Mass 125 g.
Male—Mass 174 g.
Both sexes—HB 212 mm (200–232 mm); T 46 mm (32–
54 mm).

distribution: U. townsendii occurs in southcentral Wash-
ington (USA), north and west of the Columbia River.

geographic variation: Two subspecies are recognized.

U. t. townsendii—Washington, south of the Yakima River and

north of the Columbia River (USA). This subspecies has

a chromosome number of 2n = 38.

U. t. nancyae—Washington, north of the Yakima River and

west of the Columbia River (USA). This subspecies has

a slightly lighter dorsum, and a chromosome number of

2 n = 36.

conservation: IUCN status—vulnerable. Population

trend— decreasing.

habitat: Townsend’s ground squirrels inhabit high desert

sagebrush (Artemisia) regions and cultivated fi elds.

natural history: This species is diurnal. U. townsendii is

now restricted to two subspecies found in Washington,

and little ecological information is available about these

populations. Two clear karyotypic forms, once considered

subspecies of U. townsendii (U. canus and U. mollis), are much

better known. Townsend’s ground squirrels hibernate from

late May (males) or June (females and young) until late Jan-

uary to February. Breeding occurs soon after emergence.

A single litter of 4–16 young (to judge from embryo counts)

is born within the burrow in March. Juveniles emerge

from the burrow about 4 weeks later, in late March or

Urocitellus townsendii. Photo courtesy Jane Abel.