The Fisher is considerably larger than the marten and males are considerably larger than females. It is more stockily built than the weasels, but is similar in that the head is somewhat pointed, the body elongate, and the legs short. The pelage is long except on the face. The fur is dark brown grading to black on the rump and legs; the tail is black.
Fishers once occurred throughout the coniferous and mixed forests of Oregon's Coast Range and Cascade Mountains. Currently, there is a native population in the Siskiyou Mountains and an introduced populations in the southern Cascades that remains from ODFW's reintroductions of fishers from British Columbia and Minnesota in the 1960s and 1980s.
Fishers are active year-round, but more active in summer than in winter. They are capable of making extensive movements in relatively short periods, and have the reputation of being fleet and agile. Its ability to prey on porcupines is unique and renowned.