A weasel is a mammal of the genus Mustela of the family Mustelidae. The genus Mustela includes the least weasels, polecats, stoats, ferrets, and minks. Members of this genus are small, active predators, with long and slender bodies and short legs. The family Mustelidae (which also includes badgers, otters, and wolverines) is often referred to as the "weasel family". In the UK, the term "weasel" usually refers to the smallest species Mustela nivalis.