Squirrels of the World

Cynomys leucurus 261

ground for about 5–6.5 weeks, when four to fi ve (range = 1–7)
emerge from the nursery burrow. Weaning usually is not
complete until one to three weeks after the juveniles fi rst
emerge from the nursery burrow, and communal nursing is
common following their fi rst emergence. C. gunnisoni is
highly social. Social groups (clans) are organized into terri-
tories that generally contain one adult male, one or more
adult females, yearlings, and young-of-the-year; neighbor-
ing groups have a minimal overlap, whereas the overlap
among group members is nearly complete. In most popula-
tions females are philopatric, and clans are composed of
close female kin. Amicable interactions among adults and
juveniles include kissing, sniffi ng anal and oral glands, and
playing; hostile interactions among adults of all species in-
clude fi ghts, chases, and territorial disputes.
The burrows of C. gunnisoni increase habitat heterogene-
ity, and the plant communities associated with these bur-
rows create signifi cant increases in that region’s biodiver-
sity. Gunnison’s prairie dogs feed on grasses, forbs, sedges,
and shrubs; insects and other animal foods are rarely eaten.
They do not cache food. Gunnison’s prairie dogs can distin-
guish between potential threats and even identify specifi c
characteristics of the threats, and they code this informa-
tion into their elaborate alarm calls. Survivorship in the fi rst
year after emergence from the nursery burrow is usually
only about 50 percent for both sexes, and less than 15 per-
cent survive through their second year. Males sometimes
live as long as 5 years, and females occasionally can be as
much as 6 years old. The principal predators of C. gunnisoni
are raptors, canids, felids, and mustelids, including endan-
gered black-footed ferrets (Mustela nigripes). Colonies suff er
drastic population declines and are often extirpated during
outbreaks of fl ea-borne sylvatic (bubonic) plague. Gunni-
son’s prairie dogs are hunted for recreation in much of their
range. They are also sometimes considered as competitors
for forage in cattle country or as a threat to livestock, due to
their open burrows that grazing animals might step into.
Although both of these concerns are exaggerated, C. gunni-
soni have been poisoned and shot for pest removal in many
areas of their range. On the other hand, some researchers
consider Cynomys to be a keystone species for ecosystem
health.

general references: Bartz et al. 2007; Davidson and Light-
foot 2008; Haynie et al. 2003; Hoogland 1998, 1999, 2003a,
2003b; Pizzimenti and Hoff mann 1973; Rayor 1988; Slobod-
chikoff et al. 2009.

Cynomys leucurus (Merriam, 1890)

White-Tailed Prairie Dog

description: The dorsum is yellowish buff color frosted

with black, with a paler venter. There is a dark brown or

black stripe above each eye, with some dark brown or black

below each eye. The tail is buff to white at the base, with a

suff usion of cinnamon and white at the tip.

size: Female—TL 353 mm ± 4 mm (315–375 mm); T 40–65

mm; Mass 925 g (675–1200 g).

Male—TL 371 mm ± 4 mm (342–399 mm); T 40–65 mm;

Mass 1139 g (750–1700 g).

distribution: C. leucurus is found in extreme southcentral

Montana, western and central Wyoming, northeast Utah,

and northwest Colorado (USA).

geographic variation: None.

conservation: IUCN status—least concern. Population

trend—decreasing.

habitat: White-tailed prairie dogs inhabit xeric and rela-

tively high-biomass mixed stands of grasses, forbs, and

shrubs in high-elevation meadows, fl ats, and gently rolling

hillsides.