The fisher (Pekania pennanti) 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.^[3]

The fisher is closely related to, but larger than, the American marten (Martes americana) and Pacific marten (Martes caurina). In some regions, the fisher is known as a pekan, derived from its name in the Abenaki language, or wejack, an Algonquian word (cf. Cree ocêk, Ojibwa ojiig) borrowed by fur traders. Other Native American names for the fisher are Chipewyan thacho^[4] and Carrier chunihcho,^[5] both meaning “big marten”, and Wabanaki uskool.^[6]