Fishers are large members of the mustelid (weasel) family; second in size only to the river otter, male fishers may weight up to 13 pounds. Solitary for most of the year, fishers prefer dense, old-growth forest where they hunt on the ground and in the trees; snowshoe hares and porcupines are their most common prey species but these omnivores also consume other small mammals, wild turkeys, grouse, fish (rarely, despite their name), fruit, nuts, mushrooms and carrion. Though they seem to have few natural predators, records of attacks by lynx, coyotes, bobcats and mountain lions have been documented.
Fishers reach sexual maturity within one year and generally have a lifespan of 5 years or less in the wild; captive animals may live ten years or more. Females give birth to an average of 3-4 kits in spring, most often using a tree cavity as a den; mating occurs soon thereafter but implantation of the fertilized eggs is delayed until the following spring. Young fishers become independent by autumn and the litter mates disperse to establish their own territories; like their parents, they may be active day or night.
Native to North America, fishers inhabit the boreal forests of Canada and mature forests in New England, the Upper Great Lakes Region and the Northern Rockies (primarily in Canada, Idaho and Montana); isolated populations have also been found in the northern Sierra Nevada. Over-trapping significantly reduced their population by the early 1900s but their numbers have since rebounded and stabilized.
