There are two living species referred to as "mink": the American mink and the European 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 weasels, otters and ferrets. The American mink is larger and more adaptable than the European mink. Due to variations in size, an individual mink usually cannot be determined as European or American with certainty without looking at the skeleton. There is one exception to this rule: all European minks have a large white patch on their upper lip, while only some American minks do. Thus, any mink with no such patch is certainly of the American variety. Taxonomically, both American and European minks 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.