LEMMING, a short-tailed, rat-like animal, related to the European voles and American meadow mice, which inhabits the high moun tains of Scandinavia. Its technical name is Myodes 'menus, and closely related species are found in northern Siberia and in Arctic Amer ica. In general appearance these animals are more like miniature short-eared, yellowish rab bits or pikas than like mice; they subsist wholly upon vegetable food, dwell in nests; Made of bark, grass, etc., in some sheltered nook, and do not hibernate but force their way about un derneath the snow in search of moss, lichens, sprouting woody plants and other edible things. They are very prolific, •rearing two broods of four to six young annually, and hence few years they become so numerous that the moue tams can no longer support the hordes. At such times, occurring at irregular intervals of sev eral years according to circumstances, an exodus takes place and great numbers of lem mings descend from the mountains and spread over the lowlands. There the easier climate, more abundant food and absence of enemies, permit a still further multiplication, so that by folloiiing season the little,animals have in creased into a plague. They wander more and more widely, overrun and damage, or some times wholly devour crops, gardens and mead ows, and make themselves a destructive nui sance. Such an invasion is felt more severely
in the narrow and fertile valleys of Norway than in the broader and more forested spaces of Sweden. At such a time concerted measures are devised to kill them off, carnivorous mam mals and birds flock to the feast and epidemic diseases often break out among them. Spread ing with a restless energy for travel, the lem mings overcome or attempt to overcome all obstacles and heedlessly plunge into lakes too large or rivers too swift to be crossed. When the remnants of the host reach the sea many of them boldly swim out in their ignorance of its magnitude and are drowned. Such overrun-. ing of the country by lemmings is not known in Arctic Asia or America, where different con ditions exist.
certain small, mice-like animals closely related to the lemmings and having similar traits, inhabit the region about Hudson Bay and the southern part of Green land, of which the most prominent is Gutsiestlus torquotus, chiefly remarkable for its turning white in winter. Other species belong to the genera Synaptomys, Lemmus, etc..