Fishers mate from mid March to early April. Implantation of the embryo is delayed until the following February, and after 50 days, the young are born. The females mate shortly afterwards, and the pregnancy cycle begins again.
One to four kits are born blind, and covered in very fine hair. They will crawl at 3 weeks, their eyes will open at 7 weeks, they will begin to climb at 8 weeks. They will be dependent on mother's milk for 8-10 weeks. At 5 months, they will venture out on their own, and after a year, will have acquired their own range. They range from 3-5 miles generally.
Male fishers weigh from 8-13 lbs., the females, from 4-6 lbs. They have 5 toes on each foot, their claws are retractable. Fishers feet are large like the lynx, so that they can travel easily on packed snow. Their ankle joints are very mobile like the raccoon, and their hind paws can rotate almost 180 degrees. They have a scent gland on the central pad of their hind paws with an identifying odor, so that males and females can locate each other for breeding
Fishers are part of the weasel family, they are for the most part carnivores, but have also been found to eat nuts, berries and mushrooms.