Fisher

Martes pennanti

Class: Mammalia

Order: Carnivora

Family: Mustelidae

Fisher range map

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Minnesota Conservation Volunteer articles

 

Hunting/Trapping information -

Furbearers

 

Fisher

The fisher is a member of the weasel family, resembling a very large mink. It weighs as much as a red fox, but has much shorter legs. Fisher are extremely agile and active predators. Excellent tree climbers, they can outclimb marten and red squirrels. They prey upon snowshoe hare, mice, squirrels, and porcupine. Fisher will also eat insects and berries.

The fisher is a remarkable predator (meat eater). It is one of a very few animals that can kill a porcupine. Despite its name, the fisher does not catch or eat fish. Instead, it eats small animals, carrion (already dead animals), wild berries and nuts.

Identification

General description: The fisher is a medium-sized long-shaped predator that belongs to the weasel family.

Length: Adult fishers are 24 to 30 inches long, including their long, bushy tail.

Weight: Female adults weigh 6 to 8 pounds, and males weigh up to 18 pounds.

Color: The fur of a fisher is a grizzled dark brown, blackish on the rump and tail, with a white or cream-colored bib on their chest.

Reproduction

Like most members of the weasel family, female fishers have what is called "delayed implantation." Females get pregnant in spring, just 10 days after they have given birth. For the next several months, the young exist as tiny embryos. Then, two months before being born, the embryos develop into fetuses. One to five young fisher are born in a hollow tree, log or rock cavity. Within days after giving birth, the female will seek out a new mate.

Young fishers stay with their mothers for just a few months. The young leave the female in early fall to find their own home territory.

Food

Fishers kill and eat mice, chipmunks, squirrels, snowshoe hares, and even deer fawns. They also eat almost any carrion as well as berries and nuts.

Predators

Few animals can take on a fisher. Because bobcats and fishers compete for the same food and habitat, bobcats occasionally kill young and adult fishers.

Habitat and range

Fishers live in a variety of young and old forest types in northern Minnesota. Sometimes they are found in western prairie areas and southeastern river valleys. They are solitary, except during the breeding season and when the young are with the female. Fishers range over 7 to 10 square miles, traveling at any time of day or night.

Fishers prefer large areas of continuous forest, particularly older timber stands. They are adaptable, but avoid open areas. They prefer the edges of conifer stands when these are adjacent to stands of deciduous trees. Hollow trees, rock crevices, slash piles, abandoned beaver lodges in dry ponds, and old porcupine dens are preferred denning sites.

Population and management

Fishers were nearly extinct in Minnesota by the early 1900s. But the population has grown steadily since then. Since the late 1970s, the population has remained at more than 10,000, enough to support a regulated trapping harvest of about 2,000 each year.

Fun facts

The fisher hunts in trees. Female fishers are pregnant for 350 days of each year.