Brown lemmings are found in the tundra regions of Siberia and North America. They can be found in arctic tundra and in subarctic alpine tundra above treeline.

(Jarrell & Fredga, 1993; Rodgers & Lewis, 1986; Stenseth & Ims, 1993c; Wilson & Ruff, 1999)

Biogeographic Regions: nearctic (Native ); palearctic (Native )

Brown lemmings have stout bodies which do not appear as elongated as other microtine rodents. Total body length is 130-180mm, averaging 150mm. Sexes are similar in size, though males are 5-10% larger than females. They have small eyes, small ears hidden under the fur, blunt muzzles, and short tails (18-26mm, averaging 21mm, including hair at the tip). Their backs and sides are tawny brown to cinnamon, with a paler underbelly; unlike some other lemming species (e.g. most species of the genus Dicrostonyx), they do not change colour in the winter. Older adults may have a rusty-coloured patch on the rump.

(Stenseth & Ims, 1993c; Wilson & Ruff, 1999)

Range mass: 45 to 130 g.

Average mass: 80 g.

• Terrestrial

Brown lemmings live in northern treeless regions, usually in low-lying, flat meadow habitats dominated by graminoids and mosses. In summer, they live in areas rich in grasses and sedges, moving in winter to mossy areas with permanent snow cover or wet meadows. (Barkley et al., 1980; Rodgers & Lewis, 1985; Stenseth & Ims, 1993c; Wilson & Ruff, 1999)

Terrestrial Biomes: tundra

Brown lemmings eat only live plant parts. For most of the year, they eat fresh grasses, sedges, and mosses (except sphagnum). In summer in areas of wet tundra, their diet consists primarily of monocot leaves, making up 76 to 90%. In winter they eat frozen (but still green) plant material, the available 1-2cm of basal leaf sheaths, and moss shoots. Mosses can make up nearly one-half of their winter diet, and are also important in dry tundra, where mosses make up about 30% of their diet.

Because their food is so low in nutrients, they must eat quite a lot of it; they forage for 1-2 hours at a time, at roughly 3-hour intervals, throughout the 24-hour day.

(Barkley et al., 1980; Batzli, 1993; Wilson & Ruff, 1999)

Brown lemmings become sexually mature quite early, normally at 5-6 weeks of age, but possibly as early as 3 weeks in some summers. Females can breed immediately after giving birth (post-partum estrus). They give birth to 2-13 young, after a 3 week gestation period. Litter size averages 8 in summer, 4 to 5 in early and late winter, and 3 in mid-winter. There appears to be no reproduction during the spring snow melt (May through early June) nor during the fall snow pack formation (September through early October).

Not much is known about their reproductive habits, but it is likely that females rear the young alone, since no males have been caught in a wild nest with young. Non-receptive captive females have been known to attack males. It is also likely that breeding is promiscuous, since males have larger home ranges than females, and there is substantial overlap in the home ranges of multiple individuals.

(Stenseth & Ims, 1993a; Wilson & Ruff, 1999)

Although there is no recognized, immediate threat to the global population of brown lemmings, they are in danger of decline in years to come. The predicted warming of the Canadian climate, and predicted northward migration of Canadian biota, may result in a reduction of the range of the brown lemming, which is limited in the north by the Arctic Ocean. Brown lemmings are quite inflexible in such traits as diet and preferred terrain, so they would be particularly sensitive to such a loss of habitat.

(Kerr & Packer, 1998)

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

No information available.

No information available.