The fisher is a carnivorous mammal native to North America, a forest-dwelling creature whose range covers much of the boreal forest in Canada to the northern United States. It is a member of the mustelid family, and is in the monospecific genus Pekania. It is sometimes referred to as a fisher cat, although it is not a cat.

The Mustelidae are a diverse family of carnivorous mammals, including weasels, stoats, badgers, otters, martens, grisons, and wolverines. Otherwise known as mustelids, they form the largest family in the suborder Caniformia of the order Carnivora with about 66 to 70 species in nine subfamilies.