Whenever the subject of fishers come up, you hear descriptions like mean, nasty and viscious, a smaller wolverine with just as much attitude. Fishers get a pretty bad rap, but when they do, there's a great deal of projecting and anthropomorphizing going on. Fishers aren't mean or evil. People are... and our motives for being so are complicated, often mean spirited, and generally not related to simply surviving.
What members of the mustelid family, the weasels, are is uncompromisingly aggressive, which is why they are such efficient and successful hunters, from the wolverine down through the fisher and marten to the ermine and least weasel. I also believe they get blamed for acts which they are usually not responsible for. For example, great horned owls, which have smaller territories than fishers, are probably much more likely to take your cat than fishers are.
The ancestors of fishers appear in North America between two and a half to five million years ago, while individual remains from 125,000 years ago, show no significant anatomical differences from modern day fishers.
Fishers are meso predators who defend and scent mark territories of about 3 square miles in Summer and five square miles in Winter, preferring mature conifer forests with good cover, large trees and fallen logs with hollows for denning. Fishers may also den under bushes or in crevices. Fisher territories often overlap, and are frequently patrolled, using shared, common routes. Male fishers have slightly larger territories, which overlap female territories, making it easier to find females for mating.
Fishers are seasonally brown to dark brown to mottled in Summer, with moulting between Summer and winter. Male fishers average three to four feet long, and can reach 8 to 13 pounds, females about half that. Fishers are not “fisher cats”, nor do they eat much fish, even though they are great swimmers, as well as climbers.
Fishers have small round ears to prevent heat loss, and broad, blackish five toed feet featuring retractable claws, which act as snowshoes. Their ankles have a rotating capability of 180 degrees, which makes them very nimble in trees, even allowing them to run down trees head first. Their rear foot pads have a central scent gland, which may assist in marking territories, and in finding other fishers during mating season.
Studies of fisher stomach contents do not commonly find domestic cats, but porcupine, snowshoe hare, wild turkey and smaller rodents are more likely prey. Know what wildlife lives around you. Understand that starvation is generally the number one killer of wildlife... it's real tough out there!... It's not like they're specifically out to get your cat, but also consider when and where to let pets out. Please don’t let your cat out in Spring, as domestic cats have devastating impacts on the young of nesting birds and small mammals. Fishers also eat some greens, insects, nuts and berries and they will scavenge dead animals.
Contrary to popular lore, fishers don't flip porcupines to attack the belly. Way too dangerous a strategy, and probably believed because someone observed the fisher eating a porcupine's organs first, with the unquilled underside the easiest way into the carcass. Rather the swift and shifty fisher attacks the porcupine's face with a series of quick bites, sort of like Muhammed Ali jabbing an opponent relentlessly to discourage them and weaken their resolve.
One surprising find from a study in Maine led by Scott McKlellan, Maine Department of Inland Fisheries and Wildlife, indicate that fishers will occasionally attack the much larger Canadian lynx, often in snowy weather, when the lynx may be taken by surprise, while trying to lay out the storm. Tracks in the snow, and the distance between canine punctures found post mortem on the lynx head, throat and neck tell the story. It appears that the fisher seizes the lynx and tenaciously holds on until the cat suffocates.
Surprisingly, the victims were not adult lynx weakened by starvation, as there were sufficient numbers of their favored prey, snowshoe hare, in lynx habitat at the time, and the lynx remains did not show anatomical signs of starvation. Fishers have less luck with bobcats, and often end up as their prey, though I wasn’t able to determine why this would be so.
Male fishers have little to do with females, except during mating season. Female fishers, like bear sows and about 100 other mammals, feature delayed implantation, which means that the blastocysts don’t implant in the uterine wall after mating, delaying pregnancy, and insuring the female will deliver one to four kits in the Spring, who will stay with her through the Summer. The female will again go into estrus in April or May, a couple of weeks after giving birth, thus starting the cycle anew.
Fishers have been trapped out and extirpated from many regions more than once, as the sale value of pelts rose and fell, but efforts to fur farm them, have been frustrated by their extended reproductive cycle. Fishers are on a strong comeback in New England, probably because of the increase in porcupines, an important prey animal. The fisher and marten trapping season in the Adirondacks is in November. Let’s hope non target animals have their calendars marked.
Black legged ticks pick up the Lyme borrelia bacterium from rodents, and then pass it on to you, your dog or your horse. Any predator, from birds of prey to small mammalian predators are therefore key in the battle against lyme disease. I believe trapping for any mammalian predator which consumes rodents, such as foxes and weasels should be suspended as we work through the expansion of the black legged tick and lyme disease into areas further north and at higher elevations. There is nothing new about lyme disease. Our ice age ancestor, dubbed Otzi, who was murdered in the French Alps 5,300 years ago, and then managed to get preserved in a glacier, apparently suffered from lyme disease.
From our experience rehabbing and releasing injured and orphaned fishers, the kits start out pretty gentle, becoming increasingly more aggressive toward each other at about four months, as well as to their keepers, until such time, even mom has had enough, and kicks them out of the den. Studies in Glacier National Park indicate that kits of the larger wolverine female, are raised by mom, but then do an apprenticeship with Dad, with the focus on hunting. I don’t know whether fishers display similar familial behavior.
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