Lemming, a small rodent of the subfamily arvicolinae or field mice, and the genus myodes (Pallas); authors have also referred it to geo-rychus (111.), lemmus (Zinck), and hypudaeus (111.). The lemmings may be distinguished from the arvicolas by the hairy soles, very short tail, long sickle-shaped claws for digging, and small size or absence of external ears; the last lower molar has four or five triangular prisms alternating with each other. The species are confined to the arctic regions of both hemispheres, and are the most northern form of rodent known; of the North American species none have been found within the United States; they live in the thick mosses and sphagnous swamps in the vicinity of the arctic circle. The Norway lemming (M. lemmus, Pall.) has a stout body 5 in. long, a short and broad head, short and robust legs, and coarse bristly hair; the whiskers are in five horizontal series; the fore feet are provided with very long, stout, and fossorial claws, the third the longest, and the thumb rudimentary; the hind feet short and broad, well armed with claws; the short tail is densely coated with hair.

The dentition consists of incisors 1/1-1/1, molars 3/3-3/3,; the skull is massive and broad, the orbits very large, the temporal fossae small, and the zygoma high; the incisors are thick, large, and much rounded anteriorly. The color above is yellowish and reddish with black markings, and yellowish white below. Its natural habitat is the mountainous regions of Lapland and Norway, from which it descends at irregular intervals in immense troops, which devour every green thing in their course, and commit as great devastations as the migratory locusts; it has been supposed that an unusual multiplication of these animals and an actual or anticipated scarcity of food impel them to these migrations. They move chiefly by night or early in the morning, proceeding obstinately in a direct line, swimming rivers, crossing mountains, and permitting nothing but an absolutely insurmountable obstacle to alter their straight course; many are destroyed by fire and water, by each other, and by rapacious beasts and birds.

They are not disposed to live in society, but dwell in a scattered manner in holes in the ground; they lay up no regular provision for the winter's use; they produce five or six young at a time, and it is said several times in a year; the flesh, which tastes like that of the squirrel, is eaten in Lapland. The food consists of plants, seeds, roots, and any vegetable matter that comes in their way. - The best known American species is the Hudson bay lemming (M. Torquatus, Keys, and Blas., or M. Hudsonius, Wagner), a cir-cumpolar animal, coming down as far as Labrador and more southward on the Pacific coast. There are no external ears, and the two middle claws of the fore feet are remarkably large; the color above is a mixed reddish brown and pale yellow, palest on the sides, beneath whitish, whiskers black, and sometimes with a whitish collar edged with brown on both sides; the color is white in winter, with a few black hairs interspersed. The length is about 5 1/3 in.; the thumb is rudimentary on the fore feet, and the two middle toes appear to have double nails, as the callous end projects under the nail.

It is an inoffensive animal, living in burrows in the ground or under stones, feeding on roots and similar substances. - For details on the lemmings, see Sir John Richardson's Fauna Boreali-Americana.

Lemming (Myodes lemmus).