266 Cynomys mexicanusgrasses, forbs, fl owers, and seeds. Their diets diff er in areas
grazed by cattle and goats, with only a modest dietary over-
lap. In fact, Mexican prairie dogs are able to persist in pas-
tures degraded by goats. The breeding season of C. mexica-
nus is protracted, and it may extend from January to late
April; many males have descended testes (indicative of re-
productive condition) from December until July. Estrus
peaks in February and March. After a gestation that proba-
bly is between 30 and 35 days, females produce a single litter
(averaging four juveniles) in burrows. The young nurse for
21–23 days, until they are weaned by late April or early May.
Infanticide is not known; however, females vigorously de-
fend nesting burrows from males, suggesting this possibility.
Mexican prairie dogs are highly social and form coteries com-
posed of one to two adult males, one to four adult females,
yearlings, and young-of-the-year of each sex. Natal dispersal
appears to occur during the second year. Group members are
amicable and greet each other by investigating one another’s
cheeks. Amicable interactions among adults and juveniles in-
clude kissing, sniffi ng anal and oral glands, playing, and al-
logrooming; hostile interactions among adults of all species
include fi ghts, chases, and territorial disputes. No informa-
tion is available about communal nursing.
Adults of bot h sexes ca n be seen in a n a ler t posture, sit t ing
on their haunches and being vigilant. C. mexicanus has two
calls: an alarm vocalization, given in response to intruders
and predators; and an elation call, emitted as an apparent af-
fi liative behavior. Their principal predators are raptors, kit
foxes (Vulpes macrotis), badgers (Ta x ide a ta x u s), and coyotes
(Canis latrans), all of which frequently stalk and attack Mexi-
can prairie dogs. Large rattlesnakes may also prey on these
prairie dogs, especially the young. In addition, sylvatic (bu-
bonic) plague is a known cause of local extinctions. Loss of
habitat, due to its conversion to agriculture and livestock
grazing, is a major threat to their persistence. Mexican prairie
dogs are considered (erroneously) as competitors with live-
stock for forage, and they have been the target of intensive
and widespread poisoning historically, which may have re-
duced their range by 65 percent over the last 150 years.
general references: Ceballos, Mellink, et al. 1993; Ce-
ballos and Wilson 1985; Hoogland 2003a, 2003b; Mellado
and Olvera 2008; Trevino-Villarreal 1990.
Cynomys parvidens (Allen, 1905)
Utah Prairie Dog
description: Utah prairie dogs are buff to cinnamon to
clay on the dorsum, with a light cinnamon to pale buff ven-
ter. The upper lip and the chin are a pale buff. A dark brown
or black stripe is found above each eye, with some dark
brown or black below the eye. The tail grades from a proxi-
mal buff to a distal white.size: Female—TL 320 mm (290–368 mm); T 52 mm (47–56
mm); Mass 785 g ± 15 g in June–July.
Male—TL 341 mm (299–370 mm); T 54 mm (49–62 mm);
Mass 1080 g ± 15 g in June–July.distribution: This species is found in southwestern and
southcentral Utah (USA).geographic variation: None.conservation: IUCN status—endangered. Population
trend—decreasing, with fewer than 8000 individuals. C.
parvidens is listed as threatened under the U.S. Endangered
Species Act.habitat: This species is found in open grasslands and sage-
brush fl ats in mountain valleys with well-drained soils. C.
parvidens appears to avoid slopes and areas where vegeta-
tion obstructs its ability to view its surroundings.natural history: The Utah prairie dog is diurnal. It hi-
bernates in burrows for lengthy winters that last up to seven
months. Adults typically emerge in February and enter hi-
bernation in late summer or early fall, whereas juveniles
remain active into October or November. Females usually