The fisher (Pekania pennanti) is a small carnivorous mammal native to North America. It is a member of the weasel family.The fisher is closely related to but larger than the American marten. It is a forest-dwelling creature whose range covers much of Canada to the northern United States. They are sometimes also called pekan, pequam, wejack, and woolang. It is also called a fisher cat, although it is not a feline.

Males and females look similar. Adult males are(35–47 in) long and weigh (8–13 lb). Adult females are (30–37 in) long and weigh (4–6 lb). The fisher prefers to hunt in full forest. It prefers the snowshoe hare and is one of the few animals able to prey successfully on porcupines. Despite its common name, the fisher rarely eats fish.

Fishers have few predators besides humans. While fishers usually avoid human contact, encroachments into forest habitats have resulted in some conflicts.

Although fishers are competent tree climbers, they spend most of their time on the forest floor. Since female fishers require moderately large trees for denning, forests that have been heavily logged and have extensive second growth appears to be unsuitable for their needs. Fishers tend to avoid areas with deep snow. Habitat is also affected by snow compaction and moisture content.