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Urocitellus brunneus

Idaho Ground Squirrel

Order: Rodentia
Family: Sciuridae

Image of Urocitellus brunneus
Spermophilus brunneus - showing subspecies endemicus (left) and brunneus (right), distinguishable by coloration and location
Click to enlarge. (61 kb)

Conservation Status: Endangered. Populations are fragmented and declining.


The Idaho Ground Squirrel is the only mammal endemic to Idaho. One subspecies, Spermophilus brunneus brunneus, lives only in about two dozen mountain meadows, and in 1998, biologists counted only 500 of them. Other subspecies may fare better, but the life of a ground squirrel is perilous. Only 40-60 percent of the adults survive their 8-9 month hibernation, and mortality is as high as 90 percent for juveniles. Females can mate for only a few hours a year, shortly after they emerge from hibernation. After mating (in the burrow) males guard the females from other males, which exposes the males to predation by prairie falcons and goshawks.

Also known as:
Idaho Spotted Ground Squirrel

Sexual Dimorphism:
Males are slightly larger than females.

Length:
Average: 233 mm
Range: 209-258 mm

Weight:
Range: 120-290 g

References:

Howell, A.H., 1928.  Descriptions of six new North American ground squirrels, p. 211.  Proceedings of the Biological Society of Washington, 41:211-214.

Links:

Mammal Species of the World

Mammalian Species, American Society of Mammalogists' species account

Distribution of Urocitellus brunneus