North Cascades

Threatened and Endangered Species

Pacific Fisher Martes pennanti pacifica The Pacific fisher is a member of the weasel family. The fishers have long, thin bodies that measure 31-40 inches in length. Their fur is mostly dark brown. Individuals weigh between three and 18 pounds, with the male being larger than the female. Fishers require a great deal of undisturbed land; they have home ranges of 50-150 square miles depending upon food abundance. "Most records of fisher are in western hemlock, Pacific Silver fir, and Sitka spruce forest zones" (Bob Kuntz, NPS wildlife biologist, personal conversation). They den in hollow trees and rocky crevices. Fishers are mostly nocturnal. The prey upon porcupine and snowshoe hare, although they do eat smaller mammals, fruit, and other plants. The fisher's stomach can soften porcupine quills enough for them to pass through the animal's intestinal tract. (Talk about an adaptation!) "Fishers can rotate their hind feet almost 180 degrees for running down tree trunks. Apparently, they're fast enough to run down and kill martens. The only predators tough enough to overcome fishers rarely consider it worth the fight and aren't fast enough to chase them either" (Matthews, Dan. Cascade Olympic Natural History. 1988. InterPacific Printing Corporation. p.345.) Trapping, timber harvesting activities, and human settlement are thought to be responsible for the reduction in the fisher population.