The fisher is a North American marten. Despite its name, this animal seldom eats fish, but is a typical marten. It is a medium sized mustelid, agile in trees and slender enough of body to pursue prey into hollow trees or burrows in the ground.

The fisher is found from the Sierra Nevada’s in California to the Appalachians in West Virginia and north to New England (where it is often called a fisher cat). It is also found in southern Alaska and across most of Canada. Fishers are present in low density in the Rocky Mountains, where most populations are the result of reintroductions. Fishers are most often found in coniferous and mixed forests with high, continuous canopy cover.

Adults weigh between 4 to 15 lbs (2 and 7 kg) and are between 29 to 47 inches (65 and 125 cm) long, with the males larger and heavier than the females. Their coats are darkish brown, with a black tail and legs. Some individuals have a cream-colored patch on the chest. All four feet have five toes with retractable claws. Because they can rotate their hind paws 180 degrees, they can grasp limbs and climb down trees headfirst. A circular patch of hair on the central pad of their hind paws is associated with plantar glands that give off a distinctive odor and is used for communication during reproduction. Fishers are also known for one of their calls, which is often said to sound like a child screaming. It can be mistaken for someone in dire need of help.

Fishers are solitary hunters, feeding mainly on small herbivores and omnivores such as mice, porcupines, squirrels and shrews. Fishers also eat carrion consisting of larger mammals such as deer. Female fishers first breed at one year of age. The fisher-breeding season spans late February through late April. Litters are produced annually. The young are born in dens high up in hollow trees.

Fisher populations have declined because of loss of forest habitat and, in the past, because of trapping for their fur. They have the reputation of being shy and secretive. They are difficult to breed in zoos.