weasel

Any of various small, short-legged, lithe carnivorous mammals with bushy tails, especially the genus Mustela, found worldwide except Australia. They feed mainly on small rodents although some, like the mink M. vison, hunt aquatic prey. Most are 12–25 cm/5–10 in long, excluding the tail.

Included in this group are the North American long-tailed weasel, the northern hemisphere ermine or stoat, the Eurasian polecat, and the endangered North American black-footed ferret. In cold regions the coat colour of several species changes to white during the winter.

Black-footed ferrets were so close to extinction in 1987 that the entire wild population was taken into captivity. The captive population has grown from 18 then to 350 in 1998. Some have also been released back into the wild, where the population stands at between 50 and 60.