Male Fishers may weigh as much as seven kilograms, but females weigh much less. The fur of the Fisher, particularly the female, is soft and glossy, dark brown with some silvery tipping of the hairs. Fishers and Martens both have curved claws, and they are excellent climbers. These animals are found throughout mainland British Columbia, with the exception of the southern Interior. They are absent from the coastal islands.
Fishers are forest animals, and seem to be most common in mixed coniferous and deciduous woodlands.
They prey on small mammals and birds, but they are large enough to take grouse and porcupines when they are available. The prickly problem of porcupine consumption is handled deftly, as the Fisher quickly turns his prey on its back to expose its vulnerable belly. Like many members of the family, Fishers are primarily nocturnal, but may be seen by day. Like other members of the family, the gestation includes a long period of delay before the egg is implanted in the uterus. Breeding takes place soon after the young are born in March or April, and the total gestation takes about 50 weeks.