The fisher is a North American marten, a medium sized mustelid.
The fisher is agile in trees and has a slender body that allows it to pursue prey into hollow trees or burrows in the ground.
Despite its name, this animal seldom eats fish; the name may originate from the French word fichet, which referred to the pelt of a European polecat.
The fisher is found from the Sierra Nevada in California to the Appalachians in West Virginia and north to New England (where it is often called a fisher cat), as well as 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.
There is recent evidence, however, that a Montana population persisted in a refugium despite extensive fur trapping in the area during the 1800s and 1900s.
Fishers are most often found in coniferous or mixed forests with high, continuous canopy cover.
Adults weigh between 2 and 7 kg (12-25 lbs) and are between 65 and 125 cm (27-49 inches) in length.
Males are about twice the size of females, with the smallest females having been recorded being as small as 1.4 kg (3.1 lbs), hardly larger than most other martens, and males at as much as 9 kg (20 lbs).
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 head first.
A circular patch of hair on the central pad of their hind paws marks plantar glands that give off a distinctive odor, which is believed to be used for communication during reproduction.
Fishers are also known for one of their calls, which is often said to sound like a child screaming, and can be mistaken for someone in dire need of help.
Hunting and diet Fishers are solitary hunters.
Their primary prey include hares, rabbits, squirrels, mice, shrews, and porcupines.
While fishers and mountain lions are the only regular predators of porcupines, the fisher is the only predator to have a specialized a killing technique.
By repeatedly biting and scratching at the porcupine's face, they cause it to bleed to death.
Because most of the porcupine is covered in quills, the fisher then eats the porcupine by flipping the dead animal over.
Fishers are also known to eat ground nesting birds such as grouse and turkeys.
Often, young of the year and eggs make easy targets.
Also, in some areas fishers can become pests to farmers because they will get into a pen and kill large numbers of chickens.
Fishers have also been known to eat small pets left outside, such as stray cats and dogs.
While this is rare, when densities are high and food resources are low, animals may become desperate.