Lemmings feed on tundra grasses, branches, leaves, buds, bark of tundra shrubs and dwarf trees, berries. Forest lemmings feed exclusively on mosses and lichens. Since vegetable food is poor in minerals, the lemmings, on occasion, gnaw the dropped deer horns, the eggshell from the bird nests. Like all rodents, lemmings are quite voracious and eat almost all free time.
All kinds of lemmings are very prolific, only forest lemming gives 2 litters a year, the rest species multiply even more often – 3-4 times a year. Moreover, these northern rodents can multiply not only in the warm season (after all, summer in the tundra is short), but also in winter! Winter weddings lemmings play directly under the snow, without leaving the surface. There are no special courtship rituals for these animals. Pregnancy lasts 20-22 days, the female brings from 3 to 9 cubs. The number of young people depends on the feeding conditions: in years with an abundance of feed in the litter there may be 5-7 calves, in the famine period only 3-4. It is interesting that young lemmings are able to participate in reproduction even before they fully develop. Young females are already pregnant 3 months after birth, when they reach only half the size of adult animals. Such fertility makes lemmings the most numerous animals of the tundra.