Urocitellus washingtoni 365natural history: This species is diurnal. Long-tailed
ground squirrels hibernate in burrows from September
(males) or October to March or April; males emerge one to
two weeks before females. For individuals more than 1
year old, copulation occurs soon after female emergence.
After a 30–day gestation, a litter of three to nine young is
born in the burrow. The young begin to leave the burrow
at about 4–5 weeks of age. Only one litter is produced each
year, but greater than 90 percent of females often repro-
duce. A single male and several females traverse and de-
fend a group home range of about 0.16 ha; males scent-
mark throughout their territories. Dense colonies have
numerous conspicuous burrows, with large soil mounds
demarcating the entrances. Burrows are complex and of-
ten have multiple entrances, a substantial length (up to 15
m), and depths of up to 3 m. U. undulatus is an herbivore
and feeds primarily on green shoots, leaves, fl owers, and
seeds; however, it will eat insects and animal matter op-
portunistically. Long-tailed ground squirrels will collect
food in their cheek pouches and carry it back to the bur-
row for an overwinter food supply. This species’ primary
predators are felids, foxes, wolves (Canis lupus), mustelids,
and raptors. Alarm vocalizations are high-pitched but rela-
tively soft. Long-tailed ground squirrels formerly were
hunted in large numbers for their pelts; however, this use
has nearly ended. U. undulatus is considered a local pest
when found near agricultural areas.
general references: Badmaev 2008; Ognev 1963; Rican-
kova et al. 2006; A. T. Smith and Xie 2008.
Urocitellus washingtoni
(A. H. Howell, 1938)
Washington Ground Squirrel
description: Washington ground squirrels have a pale
smoke gray dorsum washed with a pinkish buff , with small
cream to buff fl ecks. The venter is grayish white washed
with pinkish buff , and the feet are white to buff. The tail is
grizzled gray, suff used with cinnamon above and with a
pinkish cinnamon underside; the tail is frosted with white
to buff.
size: Male—Mass 158 g in late February, 257 g in late May.
Both sexes—HB 185–245 mm; T 32–65 mm.
distribution: This species is found in eastern Washington
and northeastern Oregon (USA).
geographic variation: None.conservation: IUCN status—near threatened. Population
trend—decreasing. U. washingtoni is a candidate species for
protection under the U. S. Endangered Species Act. This
species is endangered in Oregon (USA).habitat: Washington ground squirrels occupy shrub-
steppe habitats of the Columbia River Basin and are most
abundant in areas of extensive grass cover on deep soils
with a high clay content.natural history: U. washingtoni is diurnal. After accumu-
lating fat stores, adults enter estivation that grades into hi-
bernation from late May to early June; juveniles enter estiva-
tion one to two months later. Adults emerge in January to
mid-March. Females breed within a few days of emergence.
After a gestation of 23–30 days they give birth to young in
February and March, in a nest chamber in inconspicuous
underground burrows. The young emerge in late March or
April and reach adult size by late May to early June. Female
coalitions appear to form within colonies, and group mem-
bers are highly social. Juvenile males typically disperse 880
m (on average), with a maximum dispersal distance of 3.5
km. Annual mortality rates exceed 60 percent, and maxi-
mum lifespan is less than 5 years. Badgers (Taxidea taxus),
coyotes (Canis latrans), raptors, Northern Ravens (Corvus co-
rax), and snakes are probably this species’ principal preda-
tors. Major threats to conservation of U. washingtoni are the
conversion of grasslands and sagebrush (Artemisia) steppes