Lemming is a small thickset rodent which looks like a large, short tailed meadow mouse. There are several kinds of lemmings but one most written about is the lemming of Scandinavia. Closely related species are found in Siberia and the Arctic.
These animals are like miniature short eared, yellowish rabbits. They have large head and short, thick legs. They eat vegetable food and build nests of bark or grass in some sheltered nook. They raise two broods of four to six young every year. They do not hibernate but force their way under the snow, searching for food.
The migration of the Scandinavian lemmings is one of the marvels of rodent life. Every few years they become so numerous that the mountains cannot support them. At irregular intervals, great swarms of lemmings start for new territory and do not stop for rivers, lakes or mountains. Eating everything they can find on the way, they fall prey to disease, larger animals and birds. These armies of rodents have gnawed through haystacks and crossed marshes. When they come to the ocean, they boldy swim out, in their ignorance of its size and are drowned. Their population problem is solved for a few more years.