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Brown Lemming Facts

The brown lemming (Lemmus trimucronatus) is a species of rodent native to North America, sometimes called the North American or Siberian lemming. The brown lemming, as its name suggests, is brown in color with a gray head and shoulders. Lemmings have small ears, short tails and bristles on their feet. The average brown lemming is six inches long and weighs less than three ounces.

Habitat
- The brown lemming's natural habitat is the tundra. The brown lemming is found primarily in Alaska, as well as parts of Canada, including western British Columbia, the Northwest Territories and the Yukon. Lemmings live underground in colonies and do not hibernate during winter. Predators of the brown lemming include most carnivores and some species of birds. Caribou and the Arctic fox have been known to prey on brown lemmings.
Eating Habits
- Whereas some rodents are omnivorous and even carnivorous, brown lemmings are strictly herbivorous and eat only live plants. Brown lemmings feed mainly on grass shoots, tundra grass, moss, bark, sedge, berries and lichens. During the wet summer months, they eat mostly monocot leaves. In the winter months they eat frozen plants and moss. Because the food they eat is so low in nutrients, they have to eat frequently. During a 24-hour period, brown lemmings generally forage every three hours for up to two hours at a time.
Populations
- Brown lemming populations are estimated to be between 20 and 130 per acre; however, populations are cyclical and only peak every two to five years. Because they eat so much and do not hibernate, lemmings often have to migrate in search of more food. They will often enter areas they are not accustomed to, such as towns and rivers. Brown lemmings often drown, get trapped underneath ice or make themselves vulnerable to new predators, such as wolves, hawks and owls. This behavior has led to an old myth that lemmings follow each other off of cliffs to their deaths.
Reproduction
- Brown lemmings may produce up to three litters per year and may even reproduce underneath the snow. The gestation period is 23 days. The female will give birth to between four and nine babies. Since brown lemmings are not migratory, they may engage in fights with each other, particularly during mating season or during times of overpopulation. They have incisors in their jaws that grow throughout their life span, which may contribute to their overall success as a species.

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