Mink are dark-colored, semiaquatic, carnivorous mammals of the genera Neogale and Mustela and part of the family Mustelidae, which also includes weasels, otters, and ferrets. There are two extant species referred to as 'mink': the American mink and the European mink. The extinct sea mink was related to the American mink but was much larger. A wild male mink weighs about 1 kg (2 lb 3 oz) and is about 60 cm (23+1⁄2 in) in length. Farm-bred males can reach 3.2 kg (7 lb 1 oz). The female weighs about 600 g (1 lb 5 oz) and reaches a length of about 50 cm (19+1⁄2 in). The sizes above do not include the tail, which can be from 12.8 to 22.8 cm (5+1⁄16 to 9 in). A mink's rich glossy coat in its wild state is brown and looks silky. Farm-bred mink can vary from white to almost black, which is reflected in the British wild mink. Their pelage is deep, rich brown, with or without white spots on the underparts, and consists of a slick, dense underfur overlaid with dark, glossy, almost stiff guard hairs. Mink show the curious phenomenon of delayed implantation. Although the true gestation period is 39 days, the embryo may stop developing for a variable period, so that as long as 76 days may elapse before the litter arrives. Between 45 and 52 days is normal. There is only one litter per year. They typically have between six and 10 kits per litter. Litters as large as 16 have been recorded at fur farms. The maximum lifespan of a mink is usually around ten years, but rarely exceeds three years in the wild. (Source: Wikipedia.org, CC BY-SA)