Dicrostonyx groenlandicus
Bering collared lemming
(Also: Victoria collared lemming; northern collared lemming)

Tundra biomes of Alaska; arctic islands of Canada, Northwest Territories; Greenland; St. Lawrence Island and Wrangel Island(Siberia) (Nowak, 1999; Wooding, 1982).

D. groenlandicus is mainly terrestrial and fossorial, however, this lemming can also be found swimming in the arctic waters.

The collared lemming is short and stocky with a very heavy coat year round. Pelage varies with the seasons: in summer the coat is light to dark grey with a buffy to reddish brown tone. Dark lines down the back and on the sides of the head are characteristic, however, the length of the stripe varies from ending just before the withers, to continuing down the length of the back (Hinton, 1926). The winter coat color is uninterrupted white. Dicrostonyx is the only genus in Rodentia in which the individuals have completely white coats in the winter season.

The head and body length equal approximately 100-157 mm with a tail of between 10 and 20 mm. This species is fossorial, developing a unique double digging claw in the winter to break through the ice and snow of the tundra (Marsden, 1964; Nowak, 1999). D. groenlandicus can easily be distinguished from other species of the genus by its narrow rostrum, smaller, straighter incisors and the unusually short hind foot (Hinton, 1926).

The female estrus cycle lasts for 9.6 days, occuring several times in the breeding season, which runs from January to September (it may begin early depending on the severity of the weather). After a 19-21 day gestation, a litter of between 1 and 11 is born. A female typically has two to three litters per year in the wild; however, in captivity they can have up to five. The young weigh 3.8 g (average) at partruition and are weaned at 15-20 days (Marsden, 1964; Nowak, 1999).

Members of this species have a fossorial lifestyle, using tundra sod as a substrate in the summer and snow in the winter (Wooding, 1982). Their burrows can reach up to 6 meters long and 20 cm wide, and they eventually lead to a "nest". Nests made of grasses are placed beneath the snow or inside a snow bank. The males engage in polygyny as the main breeding system. Nests are protected by the males, but evidence of territoriality is inconclusive.

Populations cycles are typical of lemmings: every few years the numbers peak, followed by a "crash" that some observors have described as a mass suicide, although this is doubtful (Hinton, 1926; Marsden, 1964; Nowak, 1999; Wooding, 1982).

The diet of D. groenlandicus consists of willow buds, fruits, flowers, grasses and twigs (Wooding, 1982). They will eat mushrooms and mosses in captivity. The morphology of the teeth suggests that they prey on insects, but this behavior has not been observed by individuals in the wild (Marsden, 1964; Nowak, 1999).

Eskimos use the soft white winter coats of the collared lemming for clothing decoration and toys for the children (Nowak, 1999).

Predators of the Varying Lemming include Norwegian snowy owls, Norwegian short-eared owls, ermines, foxes, wolves, pomarine jaegars, least weasels, falcons, gulls, hawks, wolverines and the polar bear (HInton, 191926; Wooding, 1982)

It is uncommon for this species to live longer than one year in the wild (Marsden, 1964).