Smithsonian National Museum of Natural History, North American Mammals
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Urocitellus richardsonii

Richardson's Ground Squirrel

Order: Rodentia
Family: Sciuridae

Image of Urocitellus richardsonii
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Conservation Status: Least Concern.


Richardson's Ground Squirrels inhabit short grass prairie, and when prairie lands are cultivated, they are perfectly happy to eat grain and forage crop, so they are considered pests. Like other ground squirrels, they spend most of their lives in hibernation. Adults are active for only about 110 days a year. Males emerge from hibernation in March, establish territories, and become extremely aggressive toward other males. After about two weeks, the females emerge, and on about the third day out of the burrow, are sexually receptive for a few hours. They usually mate with two or three males, and produce a litter 6-8 young. Males are the first to enter hibernation, usually disappearing in June. Females follow in about two weeks. The last to enter hibernation are the juveniles, after they attain full adult weight. Each Ground Squirrel curls up in a tight ball in its own chamber, which is insulated with dry grass.

Also known as:
Prairie Gopher, Flickertail

Sexual Dimorphism:
Males are slightly larger than females.

Length:
Average: 307 mm males; 291 mm females
Range: 283-337 mm males; 264-318 mm females

Weight:
Range: 290-745 g

References:

Sabine, J., 1822.  Account of the marmots of North America hitherto known, with notices and descriptions of three new species, p. 589.  Transactions of the Linnaean Society of London, 13:579-591.

Links:

Mammal Species of the World

Mammalian Species, American Society of Mammalogists' species account

Distribution of Urocitellus richardsonii

Image of Urocitellus richardsonii
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