The fisher (Pekania pennanti) is a small, 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 (weasel) family and is closely related to, but larger than, the American marten (Martes americana). Fishers have few predators besides humans. They have been trapped since the 18th century for their fur.