Fishers are about the size of a large house cat. Males can weigh up to 16 pounds, females just 4 to 6 pounds. (Photo: Aidan Garrity/Instagram.com/framwildlife)

In Massachusetts, fishers (Pekania pennanti) are one of the largest members of the weasel family. Only otters are larger. Although they are called fishers and fisher cats, these mammals do not fish, and they are not cats. (The term probably comes from early European settlers who thought the animal resembled the European polecat, which they called the fichet or fitche.) They are fierce hunters, however – one of the few creatures that hunt porcupines. Fishers have been spotted in the past near Fresh Pond, and are most active now because March and April is their breeding season.

Farmers and loggers in the 1700s and 1800s cleared New England’s forests, prime fisher habitat. Fur trappers targeted fishers for their valuable dense, glossy pelts. It is not surprising then that by the late 1800s, fishers no longer existed in Southern New England. In the late 1800s, as people began moving to cities and farmlands reverted to forests, fishers slowly returned. Fishers prefer wooded areas with overhead canopy because the trees prevent deep snow from accumulating, which helps them hunt in winter.

A fisher’s tail makes up one-third of its body. (Photo: A. Sanford)

In Northern New England in the 1950s, logging companies planted tree seedlings to replace the trees they had cut down. Porcupines ate the bark of these young trees, decimating the baby forests. To control the porcupine population, logging companies released fishers into the region. As you might imagine, porcupines, with 30,000 barbed quills, are difficult to kill, but fishers have developed techniques that help them in this battle. Sometimes fishers climb up a tree after a porcupine and crowd it to the edge of a branch until it falls to the ground. Or a cornered porcupine may press its vulnerable head against a tree, exposing only its quills. Most other predators give up at this point, but a fisher has ankles that rotate 180 degrees. So it jumps onto the tree trunk, faces down and attacks the porcupine’s head from above.

A fisher that finds a porcupine in the open will run in circles around it until the porcupine exhausts itself spinning around trying to expose its quills to the fisher. As the fisher circles, it lunges at and bites the porcupine’s unprotected face. The porcupine loses this protracted, bloody battle eventually. Once it’s dead, the fisher grasps its face and twists the porcupine upside down so it can devour its nonprickly underbelly.

Fishers are dark brown, even blackish in the winter and have small round ears to prevent heat loss. This fisher eats peanuts in Plymouth, December. (Photo: Laurel Weinstock)

Fishers mate in March or April, but the fertilized eggs do not implant in the female’s uterus until 10 or 11 months later in February. Once the eggs are implanted, they begin developing; in only six weeks the female gives birth to about three babies. The helpless kits, with eyes closed and little fur, are born in March, and the female mates again. The babies quickly grow furry, but don’t open their eyes until they are about six weeks old. The female nurses the kits for four months, then teaches the youngsters to kill their own prey. By five months, the kits can capture some of their own food. The youngsters stay with their mother until late summer or fall, when they disperse to begin their solitary life. Because of their delayed egg implantation, female fishers are pregnant most of the time.

In the 1920s, some entrepreneurial farmers decided to raise fishers for their pelts, which were quite valuable at the time (about $100 each). Fur farmers had already raised mink and ermine successfully, so raising fishers did not seem like a daunting task. But they didn’t understand fishers’ delayed reproductive cycle – they knew their fishers had mated in the spring, but then didn’t give birth, and concluded that fishers do not reproduce well in captivity. By the 1940s, most fisher farming had ended.

Fishers have long, weasel-like bodies and travel in an undulating lope. (Photo: Joe MacIndewar, naturalist at EarthwiseAware.org)

Fishers do not hibernate and are active during the day and at night. They tend to hunt at night during the summer and in the daytime during the winter. They follow their nose to find prey, and thus are quiet and elusive animals. The screeching noises often attributed to fishers are actually those of red foxes.

Fishers are largely carnivorous and feed on whatever is available, including squirrels, rodents, rabbits, raccoons, birds, eggs, reptiles, fruit, insects, porcupines, the occasional turkey and carrion. In 1999, wildlife biologists in Maine captured 85 adult lynxes, outfitted them with radio collars, and released them. These biologists learned a great deal about the collared lynxes – including the fact that fishers killed 10 percent of them.

Fisher tracks in the Middlesex Fells in January. Fishers have large feet that distribute their weight over the snow. (Photo: Joe MacIndewar, naturalist at EarthwiseAware.org)

Although they have a reputation for killing house cats, analysis of fisher stomachs has shown that this is rare, even in areas where house cats are common. In 1979 and 1980, for example, scientists in New Hampshire examined more than 1,000 fisher stomachs and found cat hairs in only one stomach. Other studies have found similar results.

Because they are secretive and elusive, spotting a fisher in the wild is difficult. The New Hampshire Fisher Cats, the Double-A affiliate of the Toronto Blue Jays, play in Manchester, New Hampshire, though. If you want to see a Fisher Cat, perhaps heading to Manchester is your best bet.

A fisher climbs a white birch tree in New Hampshire. Fishers have large feet, which distribute their weight over the snow (Photo: Douglas H. Domedion via Wikimedia Commons)

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Jeanine Farley is an educational writer who has lived in the Boston area for more than 30 years. She enjoys taking photos of our urban wild things.