Utah prairie dog (Cynomys parvidens)

KingdomAnimalia
PhylumChordata
ClassMammalia
OrderRodentia
FamilySciuridae
GenusCynomys (1)
SizeTotal length: 30 - 36 cm (2) (3)
Tail length: 3 - 6.5 cm (2) (3)
Male weight: 355 - 1635 g (2) (3) (4)
Female weight: 327 - 1123 g (2) (3) (4)

Classified as Endangered (EN) on the IUCN Red List (1).

The rare, herbivorous, social Utah prairie dog is not, as its name suggests, a dog, but is in fact a ground-dwelling rodent of the squirrel family (Sciuridae) (5) (6). Hamster- or marmot-like in appearance, with a short tail and small ears (7), the Utah prairie dog usually has light brown on the back, while the fur on the stomach and short tail is usually white. Above each eye is a prominent brown or black line (2) (3). 

The Utah prairie dog occurs in the state of Utah, USA. Its range stretches across the counties of Beaver, Iron, Pine and Buckskin Valley in the southern half of the state, where it occurs at altitudes from 1,500 to 2,700 metres above sea level (2) (3).

As suggested by its name, the Utah prairie dog inhabits grasslands (or ‘prairies’). It requires deep, well-drained soil in which to create its underground burrows, which are usually 5 to 7 metres deep and can have as many as 25 entrances (2) (3) (4) (5) (6).

The Utah prairie dog lives in large colonies that sometimes contain thousands of residents. Within each colony, individuals live in territorial family groups called ‘clans’, which typically contain one sexually mature adult male (at least one year old) and two or three sexually mature adult females (8) (9) (10).

The Utah prairie dog is primarily a herbivore that feeds on grasses, flowers, and seeds, but it sometimes eats insects as well (11). It is a diurnal rodent, and in good weather forages above ground from shortly after dawn until shortly after sunset (2) (3).

The Utah prairie dog hibernates for several months of each year. Emergence from hibernation depends on altitude and other factors, but usually occurs in March and April. Males usually enter and emerge from hibernation one to two weeks before females (8) (9) (10).

The mating season for the Utah prairie dog is usually in late March through early April, during which time each female is sexually receptive for only several hours on a single day. Gestation lasts for 28 to 31 days, and females rear their offspring in separate nursery burrows. The juveniles remain underground for five to six weeks after birth until they are weaned, and a litter of one to seven young first appears above ground in late May or early June (8) (9). Only about 50 percent of young survive the first year after weaning. Should it survive that first vulnerable year, the Utah prairie dog may live as long as eight years (8) (9). Female Utah prairie dogs usually first mate and successfully wean their first litter when they are one year old. Males sometimes mate when they are one year old, but commonly delay first mating until they are two years old (8) (9).

Predators of the Utah prairie dog are numerous (8) (10), and include American badgers (Taxidea taxus), coyotes (Canis latrans), long-tailed weasels (Mustela frenata), red foxes (Vulpes vulpes), golden eagles (Aquilachrysaetos), northern goshawks (Accipiter gentilis), and prairie falcons (Falco mexicanus). Juveniles and females in late pregnancy (when they cannot run fast) are especially vulnerable to predation, as are males during the mating season. A Utah prairie dog commonly gives an alarm call when it sees a predator; the most common callers are females with young offspring within earshot (8). 

The main threat to the Utah prairie dog is a common one: the invasion of its habitat by humans. Ranchers clearing land for grazing view the Utah prairie dog as a pest which spreads disease and consumes vegetation that their cattle would otherwise eat, and so commonly use poisonous bait scattered near burrow-entrances or poisonous gases injected into burrows to eliminate the prairie dog (1) (3) (11). Another threat is sylvatic (bubonic) plague, which is caused by a bacterium (Yersinia pestis) and is transmitted by fleas. Plague is an introduced disease to which the Utah prairie dog has not had time to evolve a good defence (11).  Because of these threats, Utah prairie dogs currently inhabit only about 5 percent of the area that they occupied 200 years ago (11).     

By 1991, populations of the Utah prairie dog had declined so steeply that the United States Fish and Wildlife Service classified it as an ‘Endangered’ species, making it illegal to kill, and a formal recovery plan was established. The plan involved moving prairie dog populations from private to public land, thereby removing the temptation for farmers and ranchers to poison or shoot them. As a result of the success of this, the classification was changed from ‘Endangered’ to ‘Threatened’, but, as this allows this rare species to be hunted once again, several petitioners want the status changed back to ‘Endangered’ (1) (11). 

To learn more about the conservation of prairie dogs see:

Authenticated (24/09/10) by Professor John L. Hoogland, University of Maryland, Center for Environmental Science,
http://www.umces.edu/al/people/jhoogland

  1. IUCN Red List (September, 2010)
    http://www.iucnredlist.org/
  2. Hollister, N. (1916) A systematic account of the prairie dogs. North American Fauna, 40: 1-37. 
  3. Pizzimenti, J.J. and Collier, G.D. (1975) Cynomys parvidens. Mammalian Species, 52: 1-3.
  4. Hoogland, J.L. (2003) Sexual dimorphism in five species of prairie dogs. Journal of Mammalogy, 84: 1254-1266.
  5. Hoogland, J.L. (1995) The Black-tailed Prairie Dog: the Social Life of a Burrowing Mammal. University of Chicago Press, Chicago, Illinois.
  6. Hoogland, J.L. (2003) Prairie dogs. Cynomys ludovicianus and allies. In: Feldhamer, G.A., Thompson, B.C. and Chapman, J.A. (Eds.) Wild Mammals of North America.  The Johns Hopkins University Press, Baltimore, Maryland.  
  7. Burton, M. and Burton, R. (2002) International Wildlife Encyclopedia. Marshall Cavendish, New York.
  8. Hoogland, J.L. (2007) Alarm calling, multiple mating, and infanticide among black-tailed Gunnison’s and Utah prairie dogs. In: Wolff, J.O. and Sherman, P.W. (Eds.) Rodent Societies. University of Chicago Press, Chicago, Illinois.
  9. Hoogland, J.L. (2001) Black-tailed, Gunnison’s, and Utah prairie dogs all reproduce slowly. Journal of Mammalogy, 82: 917-927.
  10. Hoogland, J.L., Cannon, K.E., DeBarbieri, L.M. and Manno, T.G. (2006)  Selective predation on Utah prairie dogs. The American Naturalist, 168: 546-552.
  11. U.S. Fish and Wildlife Service: Species Profile: Utah Prairie Dog (May, 2010)
    http://www.fws.gov/mountain-prairie/species/mammals/utprairiedog/