360 Urocitellus mollishabitat: Piute ground squirrels inhabit high desert sage-
brush (Artemisia) steppes in well-drained soils with native
plants, often near springs and irrigated fi elds.
natural history: This species is diurnal. Piute ground
squirrels begin hibernation in May (males) to July (females,
young), and this lasts until late January to February; males
emerge two to three weeks before females. Breeding occurs
from late January to March; however, reproduction can be
foregone during a drought. After a gestation of 24 days, a
litter of 5–10 young is born within a nest chamber in the
burrow. Males mature after 1 or 2 years; females typically
breed as yearlings. Only one lit ter per year is produced. Bur-
row systems can be extensive, with many short escape bur-
rows. Maternity burrows and hibernation burrows may
contain multiple openings and nest chambers, and these
burrows may penetrate more deeply (to about 1 m). Piute
ground squirrels can form colonies, but individuals in the
colonies live separately, except for mothers and their litters.
Mean home range size is 0.14 ha. U. mollis is primarily her-
bivorous, but these ground squirrels will consume insects
and other animal matter on occasion. Their diet includes
shoots, leaves, fl owers, and the seeds of grasses, forbs, and
shrubs; they of ten feed on crops. They forage on the ground
but will climb shrubs for food. Fecundity is high, but adult
survivorship is low, averaging 30 percent per year. The prin-
cipal predators of U. mollis are badgers (Taxidea taxus) and
weasels (Mustela), coyotes (Canis latrans), raptors, and North-
ern Ravens (Corvus corax). The alarm call of this species is a
short high-pitched “squeak,” often uttered before retreat to
the burrow or while standing upright and remaining vigi-
lant. Piute ground squirrels are a traditional food of local
Native American tribes; low levels of hunting or trapping
seem to have little impact on U. mollis populations. It is con-
sidered a pest in many areas and is poisoned or shot.general references: O’Hare et al. 2006; Rickart 1986;
Sharpe and Van Horne 1999; Steenhof et al. 2006.Urocitellus parryii (Richardson, 1825)
Arctic Ground Squirreldescription: A rct ic ground squirrels have a dorsum t hat is
reddish brown to cinnamon to fuscous, with white to buff
spots. The head is more tawny. The eyelids have a white to
cream ring. The sides, the feet, and the legs are buff to tawny
to cinnamon, becoming gray in winter. The venter is white
to straw yellow to cinnamon buff. The upper side of the tail
is ochraceous tawny, cinnamon, or cinnamon buff , grizzled
with black; the underside is tawny to russet.size: Both sexes—TL 332–495 mm; T 77–153 mm; Mass 530–
816 g.distribution: This species is found from northeast Yaku-
tia (= Sakha), Magaden, Chukotka, and Kamchatka Krai
(Russia) to Alaska (USA) and northern Canada.Urocitellus mollis. Photo courtesy Dean Draper.