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The fisher is an elusive animal

On a lazy summer afternoon a few years ago while I was strolling through a jack pine woodland, a large furry animal leapt from a thickly limbed nearby pine. The dark form hit the ground in a loud thud, and was immediately running as fast as it could in the opposite direction I was heading.

I had just surprised a slumbering fisher. And though the tired fellow provided me just a fleeting glimpse, I was thrilled for having observed a rare sight. While Minnesota does indeed harbor plenty of fishers, few people ever see one. In fact, some folks don't even know they're around.

Fishers are members of the weasel family. Other relatives of the fisher include the pine marten, river otter, mink, badger and wolverine. The fisher is reputed as the fastest tree-climbing mammal in North America. These rather large and powerful animals with bear-like claws can literally run up and down trees as they hunt for prey such as squirrels and porcupines, or to escape possible predators.

The fisher has a curious name. There are only a few records in existence of a fisher actually observed eating or catching fish. Undoubtedly, an opportunistic creature that will take advantage of most any available food and prey, fishers were nonetheless named in reference to fishes. That said, these highly intelligent and swift hunters of the forest are better known at finding and killing forest dwelling, terrestrial prey.

Other names for the fisher include pekan, black cat or black fox, and Pennant's cat, evidently in reference to T. Pennant, the man who gave the fisher its Latin scientific name, Martes pennanti. But perhaps a more fitting name for the fisher was what the Ojibwe traditionally called the animal: "tha-cho", which means "big marten."

Undeniably marten-like in appearance and habits, the fisher is much larger than its smaller cousin the pine marten. Both species are arboreal weasels, that is, tree-loving weasel-like mammals. And both species are known to hunt similar prey such as red squirrels, mice and voles, rabbits and hares and birds. However, the two species are not believed to be competitors.

Elusive in every way, fishers are adept at avoiding detection. In part, this stems from its nature as a nocturnal hunter. In order to capture fleet-of-foot prey like rabbits and squirrels, and sometimes even young deer, fishers are deliberate and determined hunters that take advantage of their natural surroundings and abilities. What's more, the fisher is one of the only mammals known to actively hunt and kill porcupines for food.

Fishers accomplish this by first being fast, but also by being extremely cunning. Porcupines, which are well armed with a coat of quills that can inflict serious harm to would-be predators, are creatures known for their defense strategies, not their ability to outrun or outsmart their enemies.

When confronted, a porcupine will often turn its rear toward the aggressor, puff out its quills and rely on its protective armor -- or a well-placed slap of its heavily quilled tail across the snout or body of its attacker -- in order to repel it. But what the fisher will do to counter the porcupine's defenses is to repeatedly attack the facial portion of a porcupine until the animal is disoriented or wounded badly enough in order to quickly and safely kill the porcupine without causing undue injury to itself.

Another of the many amazing attributes of a fisher is its physiology. A female fisher is only receptive to mating for a very short period of time in the spring after giving birth to her litter. Once mating commences and successful fertilization occurs, female fishers enter into an incredibly long gestation period -- about 350 days. Actually, this is common in all members of the weasel family. Still, timed so the fertilized egg attaches to the female fisher's uterine wall just months before the baby fishers are born in the springtime, this "delayed implantation" helps to ensure that the young fishers are born at the right time and have the best chance of survival.

Another unique characteristic of fishers, indeed, found in all members of the family, are its odor producing scent glands. Fishers have two anal scent glands that produce a musky odor, though not as strong as some of the other family members or closely related mammals. Mink produce stronger odors than fishers do from their glands, and skunks, of course, even more so than both mink and fisher.

Ranging mostly in forested lands, especially in mixed deciduous-coniferous forests throughout Minnesota's northern third, fishers are also found in other not-so-typical habitats. I have seen fisher tracks in the snow in far northwestern Kittson County, as well as observing a few fishers bounding along creek bottoms in western Marshall and Polk counties. They also occupy suitable habitats in central Minnesota.

Fishers are distinctive and interesting animals that few people observe in the wild. Trapped for their valuable fur during the state's closely regulated fisher trapping season, this large member of the weasel family continues to thrive while remaining virtually unseen. Once nearly extirpated from the state because of deforestation and unregulated trapping, this mysterious Minnesota mammal is abundant once again as we get out and enjoy the great outdoors.


Blane Klemek is the Bemidji area assistant wildlife manager, DNR Division of Fish & Wildlife. He can be reached at