Unlike Norwegian Lemmings, Brown Lemmings do not migrate en masse when they overpopulate their homes in the treeless regions of the north, but they do tend to wander. These are stout-bodied, herbivorous rodents with extremely short tails. Their fur is tawny brown to cinnamon, and a rusty-colored patch can be seen on older adults. Brown Lemmings are most abundant in low-lying, wet habitats with sedges, grasses, and mosses. They cannot eat dried, dead plants; they must have living ones, so what they eat changes with the seasons. During winter months, they feed heavily on mosses, which are not very digestible. Brown Lemmings have to spend many hours in a 24-hour winter day feeding to get enough nourishment. Arctic predators, including snowy owls, least weasels, and Arctic Foxes rely on Brown Lemmings, and when Brown Lemmings are in short supply, these predators usually do not breed successfully.

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Mammal Species of the World