The two living species referred to as "mink" are the European mink and the American mink. The extinct sea mink is related to the American mink, but was much larger. All three species are dark-colored, semiaquatic, carnivorous mammals of the family Mustelidae, which also includes the weasels, otters and ferrets. The American mink is larger and more adaptable than the European mink. It is sometimes possible to distinguish between the European and American mink; a European mink always has a large white patch on its upper lip, while the American species sometimes does not. Thus, any mink without such a patch can be identified with certainty as an American mink, but an individual with a patch cannot be certainly identified without looking at the skeleton. Taxonomically, both American and European mink used to be placed in the same genus, Mustela (weasels), but most recently the American mink has been reclassified as belonging to its own genus, Neovison.
The American mink's fur has been highly prized for its use in clothing, with hunting giving way to farming. Its treatment has also been a focus of animal rights and animal welfare activism. American mink have found their way into the wild in Europe (including Ireland and Great Britain) and South America, after being released from mink farms by animal rights activists or otherwise escaping from captivity.
American mink are believed to have contributed to the decline of the less hardy European mink through competition (though not through hybridization; native European mink are in fact closer to polecats than to the North American species). Trapping is used to control or eliminate feral American Mink populations.
Mink are primarily nocturnal, but bordering on crepuscular.
Mink oil is used in some medical products and cosmetics, as well as to treat, preserve, and waterproof leather.
European mink, Mustela lutreola