Monday, February 3, 2020

Fishers: Don’t Give A Damn About Their Bad Reputation

fisher provided by Adirondack Wildlife RefugeWhenever the subject of fishers comes up, you hear they’re mean, nasty and vicious – a smaller wolverine with 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, and they don’t really eat many house cats at all.

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 to the fisher and marten to the ermine and weasel. I also believe they get blamed for acts which they are not responsible for.  Great horned owls, for example, have smaller territories than fishers and are probably much more likely to take your cat.

The ancestors of fishers appear in North America between two and a half to five million years ago. 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 three square miles in summer, and five in winter. They prefer 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 like cats, 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. Despite the sometimes common name “fisher cat,” fishers are not 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. Fishers also eat some greens, insects, nuts and berries and will scavenge dead animals.

Contrary to popular lore, fishers don’t flip porcupines to attack the belly. It’s way too dangerous a strategy. 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, such as laying out a 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.

fisher by Joe KostossSurprisingly, 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 appear to have less luck with bobcats, and often end up as their prey.

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 spring, who will stay with her through 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. Fishers are on a strong comeback in New England, maybe due in part to the increase in porcupines there, an important prey animal. The fisher and marten trapping season in the Adirondacks is in November. (I hope non-target animals have their calendars marked.)

Joe Kostoss photo provided by Adirondack Wildlife Refuge.

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Steve Hall

Steve and Wendy Hall run the Adirondack Wildlife Refuge and Rehab Center in Wilmington. They've been rehabbing and releasing wild animals for over 45 years, specialize in predators, keep wolves as the cornerstone of their educational program, and have lived in the Adirondacks for the past 20 years. The Adirondack Wildlife Refuge became a non-profit about 10 years ago.

Visit www.AdirondackWildlife.org to learn more.




34 Responses

  1. Boreas says:

    I can personally attest to the fisher’s tactics with attacking porkies.Once while birding midday along RR tracks in Maine, my friend and I happened upon a poor porcupine standing in the middle of the tracks. He was breathing and moving slightly, but the entire front of his snout, eyes, and skull were missing. At first we suspected he had been hit by a train wheel, but saw no signs of this on the tracks. So our next guess was an interrupted attack by a fisher. We had no humane way to dispatch the animal, so left him where he was and hoped the fisher would return as soon as we left and finished the job. Nature is often not pretty.

    • Ethan says:

      Boreas, you never even saw a fisher? You say “so our next guess was an interrupted attack by a fisher”.
      I can see why you’d feel bad though, as would I, having to leave the porcupine to suffer.

      • Boreas says:

        We were walking toward the tracks on an access road, so didn’t have a view of the scene until we got close. We suspect the fisher saw us and took off as we approached, but was waiting nearby. I don’t believe the porcupine could have lived too long that way, so we assumed we interrupted the attack. My friend had been a trapper and knew about fisher than I did. He had heard that is how they attack porkys. Made sense to me.

        I have only seen 3 fisher in my life. I did get a night photo of one on a game camera I have behind my garage near a brook.

  2. Ed Burke says:

    Last year my trail cam in Edinburg caught the briefest glimpse of a fisher, this year one hung around a bit longer for a better look at it. https://twitter.com/EdBurkeToga/status/1217555279631519745

  3. ADK Bill says:

    I will start with Owl’s, I doubt many can lift a full size cat. Fisher mostly catch a porcupine’s in trees, and then attack the face, causing them to fall from the tree, one porcupine, will sustain a fisher for 3 weeks. If you want to see a fisher attacking, check out you tube,(Siamese Pond Trail) one has a gray fox pinned when some hikers interrupt his meal. Amazing video. I had one walking up a game trail, last hunting season, toward me. When he see me, he jumped up onto the side of a tree and hissed, turned and ran off. I have seen several over the years, that was the first one with any aggression shown. I get them all the time on trail cameras

  4. Boreas says:

    It would be interesting to see a study on the ecological viability of re-introducing a few wolverines to the ADKs. Would probably be more likely to be successful than the failed lynx project.

    • geogymn says:

      I think wolverines need a lot of snow and a lot of cold for a lot longer time than we get in the Adirondacks.

      • Boreas says:

        They don’t really NEED snow and cold – that is just what they got stuck with as they got pushed out of their historical range, which was from ocean to ocean and as far south as PA and IL. Basically, they just need a big range. An historic range map can be found here:

        https://www.amnh.org/exhibitions/permanent/north-american-mammals/wolverine

        If the wildlife corridor programs spread across the NE, a small population may be possible.

        • geogymn says:

          Not to argue but on your linked graphic did you read the notation under “Current Range”.
          I am all for wildlife corridors and the wolverine has been my favorite animal since I was a wee lad.
          I have been lucky to have come across Fishers in the wild several times both inside and outside the blue line.

          • Boreas says:

            I read it, but it doesn’t address why. Obviously, they lived much further south and had a much wider range than now. An opportunistic predator/scavenger can survive most anywhere there is food – assuming we don’t put a target on their back.

        • Jesse B says:

          Boreas, that may not necessarily be true. It has been posited that wolverines need (or at least prefer) persistent snowpack lasting until spring to serve as adequate den sites (https://www.jstor.org/stable/3801996). It is likely that they were never abundant in the southern portions of their range since conditions were less than ideal. And climate change will only make things worse. Furthermore, wolverines are far more sensitive to human presence compared to other weasels (e.g. skunks, fishers) and as mentioned require very large ranges. Unfortunately, the Adirondacks and northeast will probably not serve as good habitat for reintroduction (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4747315/)

          • Boreas says:

            No, they were certainly not plentiful here in the last thousand years or so. But they are adaptable, so I guess we’ll have to wait and see if they come back on their own as contiguous forests regrow and snowpacks diminish. Yes, they prefer snowpack to den – but mostly to avoid extreme cold. Take away the cold, and they may change their habits and habitat as well. Climate and habitat pressures are what drives evolution and sub-speciation. I give mammals a fair amount of credit when it comes to habitat loss.

            Wolverines like moose and other winterkill and Northern Ontario isn’t that far away. Virtually all animals learn early on to avoid humans, but the more adaptable species find we offer opportunity as well. Another large predator/scavenger would likely be beneficial in the Park. Just wishful thinking on my part.

            Polar bears are being pushed around as well because of the lack of sea ice. We may well see them continuing to move into other new habitats as well if the tundra continues to warm and they need to adapt to change food sources. Or they go the way of the Mammoth.

          • Boreas says:

            Jesse,

            More interesting reading, especially the quoted excerpt:

            https://www.fs.usda.gov/treesearch/pubs/28925

            “MANAGEMENT IMPLICATIONS

            Given the fragmented nature of suitable habitat conditions
            for the wolverine at the southern extent of its historical range
            in North America (Figs. 3, 4, 7), and extensive urban and
            agricultural development in intervening areas, the reestablishment of southern wolverine populations seems unlikely to occur without human intervention. Because southern
            wolverine populations appear to have been extirpated by human-caused mortality factors that no longer pose a
            significant threat, reintroduction may be an appropriate
            management strategy. However, the potential effects of
            increased human activities and disturbance on the reestablishment and persistence of wolverine populations should receive careful consideration during reintroduction planning.”

    • Ed Burke says:

      That project may have failed because they sourced their lynx from Yukon Territory. One DEC biologist thought the project would have had better success had they trapped them in the Gaspé Peninsula of Quebec where the environment is similar to the Adirondacks.

  5. Suzanne says:

    Several times I have seen a fisher crossing our road at night, always at the same spot, and neighbours down the hill see his tracks in the snow. My parents told me that in the ’30s Charley Beede had a pet fisher (not exactly a cuddly pet, one would think) and I’ve wondered whether this one may be a descendant. Walking down Phelps Brook one afternoon several years ago, I saw a fisher kit running down the opposite bank. A friend was chased up the Giant trail by an angry fisher and said it was a scary experience.

  6. Jeffrey Dickson says:

    in the opening paragraph – I believe the author has confused the words “viscous” and “vicious”. Might want to check on this.

  7. Tim Quade says:

    You should not be writing until you post accurate history. The earth is 6 to 10 thousand years old certainly not millions. People like you should not even be allowed to continually deceive an already messed up society.

    • John Warren John Warren says:

      I’m thinking you shouldn’t breed.

    • Boreas says:

      The Flat Earth Society?

      Heck, I have underwear older than that!

    • Steve Hall Steve Hall says:

      People like me? Tim, is this satire? The earth is actually around 4.5 billion years old, and there are a number of means of dating the earth, all of which pretty much agree, give or take 50 million years. One exception is the Bible, with the Old Testament written down about 3500 years ago by folks who didn’t know why it rained, never mind how the universe worked, but a later “scholar” decided that by adding the generations since Adam, he could figure out how old the earth was. Let’s hope you’re not a school teacher.

  8. Wendy Block says:

    Fischers seem to be fond of chickens, too! I also recently saw one run across my rd with a large crow in its mouth!

  9. Charlie S says:

    ” I also recently saw one run across my rd with a large crow in its mouth!”

    What is rd?

  10. Charlie S says:

    “The earth is 6 to 10 thousand years old certainly not millions.”

    I’ve been doing genealogical research and I can attest this is an untrue statement. I discovered a great great grand great, grander great, greater grand to the 200th great ancestor who used to sell firewood to aborigines in caves in a remote stretch of the land that is now Alsace Lorraine.

  11. John Knudsen says:

    Very much enjoyed the article on the Fisher! I am from Rome, NY lived in NH last 25 years. We descend on Eagle Bay Village with friends for a week each July! Noted your reference to increase of Fishers in NE – we can attest to that. I would like to know more about that blood curdling (scream) or cry usually late at night! Last time I shined a flashlight ? toward the sound and got 4 bright beady eyes looking back from at least 30+ feet up a stand of tree about 50 yards off our Lake shore !! Thanks for the info !!

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