[citation needed] In winter, its fur turns white, and it has large digging claws on its front feet.

[3][4][5] It feeds on grasses, sedges and other green vegetation in summer, and twigs of willow, aspen and birches in winter.

[citation needed] Predators include snowy owls, gulls, wolverines, the Arctic fox and the polar bear.

[citation needed] It makes runways through the surface vegetation and also digs burrows above the permafrost.

[citation needed] Lemming populations go through a three- or four-year cycle of boom and bust.