The family Mustelidae (55 species in 24 genera) is a diverse family, the largest and probably the oldest extant (living) family in the order Carnivora, there are different subgroups within the major group . Weasels include weasels, mink, ferrets, stoats and polecats; martens include martens and fishers; badgers include badgers and wolverine; and otters include sea otters and river otters.