The Fisher, Martes pennanti, is a North American marten. Despite its name, this animal seldom eats fish, but is a typical marten, a medium sized mustelid agile in trees and slender enough of body to pursue prey into hollow trees or burrows in the ground. Their name is thought to originate from the French word fichet, which referred to the pelt of a European Polecat.

The Fisher is found from the Sierra Nevadas 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. They are most often found in coniferous and mixed forests with high, continuous canopy cover. Adults weigh between 2 and 5 kg and are between 75 and 120cm in length, with the males larger and heavier than the females. Their coats are darkish brown, with a black tail and legs, and in some individuals a creamish patch on the chest. All four feet have five toes with retractable claws. Because they can rotate their hind paws by 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 is associated with plantar glands that give off a distinctive odor and is believed to be used for communication during reproduction.

Fishers are solitary hunters, feeding mainly on small herbivores such as mice, porcupines, squirrels and shrews. Female fishers breed first at age 1. The fisher breeding season spans late February through mid-April. After breeding, there is a ten month delay before implantation of the blastocyst phase of the embryo, causing gestation to last a whole year. A litter is 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, and they are difficult to breed in zoos. However, in some places particularly in north-eastern North America, where forest habitat is recovering near to towns, fishers seem to be habituating to human presence and are now seen more readily; there have been reports of them entering suburban areas and scavenging for rubbish, and occasionally attacking domestic animals.

External links

• Animal Diversity Web entry by C. Rhines