The collared lemming is one of the most interesting Arctic animals because of how it has adapted to the cold Arctic temperatures. It is not a "true" lemming although it is closely related to the lemming. It is a small rodent that burrows under the snow or ground making extensive runways and nesting areas. The collared lemming grows enlarged claws on the third and fourth 'fingers' of its front feet. The lemming has smaller ears and tails than other rodents. The collared lemming is the only true rodent that turns white in the winter.Mating may occur as early as January, but usually takes place from March to September. During the height of the summer breeding season all females are pregnant. Each female may have up to 3 litters a year with an average of 4 and one half young per litter. Baby lemmings are born under the snow and drink their mother's milk to survive. Few lemmings live over a year.Only in the Arctic tundra. During the summer collared lemmings live on the high, dry areas of the tundra. They burrow under the rocks. During the winter the collared lemmings move to lower meadows where there is more snow In summer their main foods are tender shoots of grasses and shrubs. During the winter they eat bark and twigs off willow and dwarf birch.