Northern Bog Lemmings have a large geographic range, but they are seldom encountered, and the reason for their apparent scarcity is not known. Their preferred foods sedges and grasses are abundant, and they do not have very limiting habitat requirements. These short, stocky rodents are active all year. When there is no snow cover they are active both on the surface and in burrows, but they are more exposed to predators in the summer, and so spend more time underground. Freshly clipped vegetation and droppings indicate their presence. In the winter, they build nests of grasses, sedges, and mosses on the ground, beneath the snow. They breed from May until late August, have litters of 2-8, and females can bear more than one litter a season.

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Mammal Species of the World