Clethrionomys gapperi
(Southern Red-backed Vole)

Order: Rodentia
Order Description:Rodents
Family: Cricetidae
Family Description:
Mice and Rats

This small, mouse-type mammal has dark brown hair on its back with a reddish, rusty colored band from its head to its tail. Its is grayish to whitish underneath. Its short tail is somewhat bicolored. Total length is about 5 to 6.8 inches (124-170 mm), tail length is 1.4 to 1.8 inches (34-45 mm), and they weigh 0.6 to 0.7 ounces (18-22 g).

Most of forested Canada, south through Rockies, northern Great Plains, northern Great Lakes, New England, and Appalachian Mountains.

Prefers cool, moist, deciduousClick word for definition, coniferousClick word for definition or mixed forests, especially areas with large amounts of ground cover. Will also use second-growth areas. Mossy logs and tree roots in coniferous forests are optimal. Idaho study found species prefers mature grand fir stands over younger stands.

The red-backed vole might be best described as an opportunistic feeder; feeding on fungi (mushrooms) during summer and fall, but shifting to seeds, some roots and bark during the winter. They are also known to eat insects.

They are active year-round, and they appear to be mainly nocturnalClick word for definition. Like deer mice, they travel under thj snow all winter and range over an area of about 1.3 acres (0.5 ha). They build round nests about 4 inches across, composed of grasses and other fine materials. The nests are on the ground and usually tucked under logs or stumps. They appear to have a large water requirement for their size (compared to other similar-sized mice) which probably accounts for their moist habitat requirements. They are know to be important dispersers of viable spores of mycorrhizal fungiClick word for definition and nitrogen-fixing bacteria. Mature females are thought to be territorial. Their populations are do not cycle like other “voles”. In Idaho, population density peaks in late summer to early fall and density up to 26 per acre (65 per ha) have been recorded. This species does not colonize area that have been recently burned, and clearcut logging may reduce their populations. This species is preyed upon by mustelids, canids and raptors. The red-backed vole is often the most common small mammal in coniferous forests.

They breed in mid-January to late November, but peak breeding activity occurs February to October. Gestation lasts 17 to 19 days, and litterClick word for definition size varies from 1 to 9 young (average 5.6 in Alberta, 6.5 in Colorado). In Alberta, young females produce 1 to 4 litters per year, older females produce 1 to 6; in Colorado, females produce 2 litters per year, and young-of-year breed as well.

Status: Unprotected nongame species

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Important State References:
Scrivner, J.H. and H.D. Smith. 1984. Relative abundance of small mammals in four successional stages of spruce-fir in Idaho. Northwest Science 58:171-176.

Information written by Donald Streubel,© 2000
Map image provided by
Stephen Burton,© 2000
Design by Ean Harker©1999, 2000.