WEASEL. The smallest species of the group of animals of which the polecat and stoat are well-known members (see MAMMALIA, vol. xv. p. 440). It is Mustela vulgaris of Linnoaus, but belongs to the section (Putorius) of the genus which has but three premolar teeth on each side above and below, instead of four as in the martens (to which Mustela is commonly restricted) and hence is now called Putorius vulgaris. The dentition is i c ^, p 4, m -g- = f; total 34.
The weasel is an extremely elegant little animal, with elongated slender body, the back generally much arched, the head small and flattened, ears short and rounded, neck long and flexible, limbs very short, five toes on each foot, all with sharp, compressed, curved claws, tail rather short, slender, cylindrical, and pointed at the tip, fur short and close. The upper parts, outside of limbs and tail, are a uniform reddish-brown, the under parts pure white. In very cold regions, both in Europe and America, it turns completely white in winter, but less regularly and at a lower temperature than its near ally the stoat or ermine, from which it is easily distinguished by its smaller size, and by its wanting the black end of the tail. The length of the head and body of the male is usually about 8 inches, that of the tail 2J inches; the female is smaller. The common weasel is pretty generally distributed through-out Europe, Northern and Central Asia, British North America, and the northern portions of the United States. It possesses in a full degree all the active, courageous, and bloodthirsty disposition of the rest of the genus, but its diminutive size prevents it attacking and destroying any but the smaller mammals and birds. Mice, rats, voles, and moles, as well as frogs, constitute its principal food. It is generally found on or near the surface of the ground, but it can not only pursue its prey through very small holes and crevices of rocks and under dense tangled herbage,
but follow it up the stems and branches of trees, or even into the water, swimming with perfect ease.
It constructs a nest of dried leaves and herbage, placed in a hole in the ground or a bank or hollow tree, in which it brings up its litter of four to six (usually five) young ones. The mother will defend her young with the utmost desperation against any assailant, having been often known to sacrifice her own life rather than desert them.