ERMINE, an alternative name for the stoat (Mustela erminea), applicable in its proper sense only when the animal is in its white winter coat. This animal measures loin. in length exclusive of the tail, which is about 4in. long, and bushy towards the point. The fur in summer is reddish brown above and white beneath, changing in the winter of northern latitudes to snowy whiteness, ex cept at the tip of the tail, which at all sea sons is black. In Scottish specimens this change in winter is complete, but in those found in southern England, it is usually only partial. The white colour is protec tive ; it also retains heat better than a dark covering. The colour change seems to be due, not to a moult, but to phagocytes de vouring the pigment-bodies of the hair. See further the articles COLOURS OF ANI MALS and PHAGOCYTOSIS.
The species is a native of the temperate and subarctic zones of the Old World, and is represented in America by a closely allied form. It inhabits thickets and stony places, and frequently makes use of the deserted burrows of moles and other underground mammals. It feeds on rats, water-rats and rabbits, which it pursues with pertinacity and boldness.
It takes readily to water, and will even climb trees in pursuit of prey. The female brings forth five young ones about the beginning of summer. The winter coat of the ermine forms one of the most valuable of commercial furs, and is imported in enormous quantities from Norway, Sweden, Russia, and Siberia. (See FUR; FUR-BEARING ANIMALS.)