Traits: Small mouselike mammal with a thick neck and very short tail; two gnawing teeth (incisors) on both upper and lower jaws

Habitat: Alpine and lowland tundra, muskegs

Foods: Shoots and leaves of grasses and sedges; bark, twigs, and buds of willow and dwarf birch; some insects, berries, fungi

Eaten by: Owls, jaegers, gulls, rough-legged hawks, arctic foxes, weasels, wolves

Do You Know? Collared lemmings turn white in winter and grow shovel-like claws for digging through ice and snow.