Fisher

Name and taxonomy

The name fisher has nothing to do with fish. It comes from the Dutch fisse or visse, the word for a polecat or its pelt, which the animal resembles. A 19th century naturalist claimed the name came from the animal's taste for fish bait in traps, but that is probably local lore. The species name pennanti honours Thomas Pennant, who described it in 1771. Buffon had described the same specimen in 1765 and called it a pekan, a name still used in some regions.

Indigenous names include wejack, from an Algonquian word, and thacho in Chipewyan and chunihcho in Carrier, which both mean big marten. Smith placed the fisher in the marten genus Martes in 1843. DNA work in 2008 showed it was distinct enough for its own genus, Pekania. Older sources still write Martes pennanti. Three subspecies were named in 1935, but later work found no way to tell them apart, so the fisher is treated as one form.

Evolution and relatives

The fisher's ancestors crossed into North America in the Pliocene, between 5.0 and 2.5 million years ago. Two extinct relatives, Pekania palaeosinensis and P. anderssoni, are known from eastern Asia. The first true fisher, P. diluviana, appears in the Middle Pleistocene of North America and seems related to the Asian fossils. The living species is known from about 125,000 years ago, and it has barely changed since. Fossils show it once lived further south than it does today.

Pekania differs from the weasels in having four premolars in each jaw, where Mustela has three. The fisher has 38 teeth in all. GBIF notes a suggestion that the fisher and the wolverine may form a group of their own within the martens. Its nearest living relatives are the American marten and the Pacific marten, both smaller.

Appearance

The fisher is long, thin and low to the ground, with short legs and a bushy tail. Males run 90 to 120 centimetres in total length and weigh 3.5 to 6 kilograms. Females measure 75 to 95 cm and weigh 2 to 2.5 kg, so a big male is about twice a female's weight. Head and body take up 47 to 75 cm, and the tail adds 30 to 42 cm. The heaviest male on record weighed 9 kg.

The winter coat is dense and glossy, 30 millimetres deep on the chest and 70 mm on the back. It runs from deep brown to black and looks blackest against snow. Three-toned guard hairs give the face and shoulders a gold or silver frost. The belly is brown with scattered white or cream patches, and many animals carry a cream patch on the chest. The coat lightens and turns patchy in summer, and the moult runs from late summer to November or December.

Each foot has five toes with retractable claws, and the feet are broad, which helps on snow. Coarse hair between the pads of the hind feet gives grip on ice and bark. The ankle joints turn almost 180 degrees, so the fisher can come down a trunk head first. A round patch of hair on each hind pad marks a scent gland that swells in the breeding season.

Habitat and range

The fisher lives in the boreal and mixed forest belt that runs from Nova Scotia to the Pacific coast of British Columbia and into Alaska. It reaches Great Slave Lake in the north and the mountains of Oregon in the south. Separate populations live in the Sierra Nevada of California, across New England, in the Catskills and down the Appalachians to Virginia. It never lived on the prairies or in the southern states.

It wants continuous forest with a closed canopy, above 80% cover, and it avoids stands under 50%. Old growth suits it best, because a female needs a large hollow tree for her den. Heavily logged forest with young second growth does not meet that need. It likes a floor littered with fallen logs, and in the fire-prone west it keeps to riverside woodland. It avoids deep soft snow.

The fisher was wiped out across the southern and eastern parts of its range in the late 19th and early 20th centuries. Releases brought it back to Oregon in 1961 and to Crater Lake from 1977 to 1980. More releases went to Washington from 2008 and to the northern Sierra Nevada from 2008 to 2011. In the east it has moved into farmland and suburbs as far south as northern New Jersey.

Diet and hunting

The fisher is a generalist hunter that takes whatever it can overpower alone. Snowshoe hares and porcupines are its main prey, with squirrels, mice, shrews and birds behind them. It also eats insects, nuts, berries, mushrooms and small apples, and it scavenges deer carcasses. Despite the name, it is not known to eat fish. It sometimes kills animals as large as raccoons, foxes, martens, bobcats and Canada lynx.

In northern Maine, biologists recorded 14 lynx killed by fishers between 1999 and 2011. The fisher attacked lynx that were bedded down in snowstorms, with a single hard bite to the neck. In that study area, fishers were the leading cause of lynx deaths. Where fishers are common, martens are usually scarce, and the reverse.

The porcupine kill is the fisher's best-known feat. The old story that it flips the porcupine and scoops out the belly was shown to be wrong in 1966. Instead it circles and bites the unprotected face over and over, and the porcupine dies after about 25 to 30 minutes. Web sources say the fisher eats the organs first and returns to the carcass over several days. Where fishers were wiped out, porcupines multiplied and stripped bark from timber, and releasing fishers brought the numbers down again.

Behaviour and social life

The fisher lives alone and meets other fishers only to mate. It is most active at dawn and dusk, all year round, though ADW records activity by day and night. Males move more in the mating season, and females move least while pregnant. Males sometimes fight each other, which fits a solitary life.

A hunting range covers about 6.6 square kilometres in summer and 14.1 in winter, and up to 20 in poor habitat. ADW gives home ranges of 15 to 35 square kilometres, averaging about 25. A male's range overlaps with several females but seldom with another male. The fisher follows set trails through its range, on the ground and through the trees.

It climbs and swims well, but it does most of its hunting on the forest floor, working around fallen trees. It rests in logs, stumps, hollow trees, brush piles and ground burrows. In winter it digs snow dens, reached by long narrow tunnels. Like the marten, it can stretch its body to follow prey into holes and hollow trunks.

Communication and senses

The fisher has good smell, hearing and sight. Scent is its main language. The glands on its hind feet enlarge in the breeding season and probably lay a trail that lets males and females find each other. Its rounded ears pick up the small sounds of prey under leaves and snow.

The fisher is a quiet animal, and no scream is recorded for it in the sources. The blood-curdling night shriek that people blame on the fisher cat is usually a red fox or an owl. Like other mustelids, it probably hisses and growls when cornered.

Reproduction and life cycle

The fisher's breeding cycle takes almost a full year. Mating happens from late March to early April, and ADW notes that copulation may last up to seven hours. The fertilised egg then stops growing for about ten months. It implants in mid February, and active pregnancy lasts about 50 days. The female bears one to four kits, usually three, high in a hollow tree. She comes into season again 7 to 10 days later and goes out to mate, so an adult female is almost always pregnant.

Kits are born blind, nearly naked and about 40 grams. They crawl at about three weeks and open their eyes at about seven weeks. They climb at eight weeks, take milk for eight to ten weeks and then move to solid food. By four months they hunt for themselves and no longer tolerate their litter mates. When they are five months old the mother drives them off, and by one year each has its own range.

A female first breeds at one year and has her first litter at two. A male first breeds at two years. Wikipedia gives a natural lifespan of about 7 years, and ADW says a wild fisher can reach 10. One captive animal lived 14.3 years.

Predators and threats

An adult fisher is rarely hunted by anything but people. Bears, coyotes, lynx, bobcats, cougars, wolverines, golden eagles, bald eagles and perhaps great horned owls can take one. Young fishers fall to hawks, red foxes, lynx and bobcats. It carries roundworms, tapeworms and flukes, including Trichinella, but disease is uncommon.

Trapping is the old threat and logging the modern one. Between 1900 and 1940, unregulated trapping nearly wiped the fisher out across the southern half of its range. Pelt prices soared again in the early 1970s and caused a second crash in 1976. In California, rat poison laid at illegal cannabis farms is a newer killer. A 2012 study found 79% of tested fishers carried anticoagulant poisons, and a 2015 follow-up raised that to 85%, with 13 dead in all.

Population and conservation

The IUCN lists the fisher as Least Concern. No range-wide count exists, but the species has recovered across much of its former range. Most states restricted trapping by the 1930s, and full protection came in 1934. Canada still trapped over 3,000 a year through the low years, and in 1999 sold 16,638 pelts. Forest regrowth on abandoned farms gave the animals somewhere to return to.

Trapping resumed in the United States after 1962, closed again after the 1976 crash, and reopened in 1979 with short seasons and bag limits. Numbers have risen steadily since. The fisher is protected in Oregon, Washington and Wyoming, and the California population is listed as threatened under the Endangered Species Act. Washington released 90 animals on the Olympic Peninsula from 2008, and about 40 went into the northern Sierra Nevada from 2008 to 2011. Radio collars and cameras show the released animals are breeding.

Relationship with humans

The fisher's story with people is mostly the story of its fur. Trappers have taken it since the 18th century for scarves and neck pieces. Its tail went into spodiks, the fur hats of some Hasidic Jews. Winter pelts fetch the best prices. In 1936 a pelt sold in New York for 450 to 750 dollars. In 1979 the Hudson's Bay Company paid 410 dollars for one female pelt. By 1999 the average Canadian pelt brought only 27 dollars.

Fur farmers tried to breed fishers in the 1920s but failed, because no one yet knew about delayed implantation. Females mated in spring and then seemed never to give birth. Most fisher farms closed by the late 1940s. Zoos find the animal a poor exhibit, since it hides all day.

Unprovoked attacks on people are extremely rare, though a fisher will bite if cornered. Two attacks on boys, one aged six and one aged 12, have been blamed on fishers. Fishers raid chicken coops, and they are accused of taking cats. A 1979 New Hampshire study found cat hair in one of over 1,000 fisher stomachs, and two later studies found none.

In culture and myth

In Anishinaabe tradition, Fisher is a bold helper who brings warmth or fire to people. One telling has his tail burned black in the deed. In some Indigenous star lore, Fisher was set among the stars, and the Big Dipper is his body. Woodland peoples usually cast the fisher as a brave hero, while the weasel and the wolverine play the villains. The Abenaki name pekan and the Cree ocêk passed to fur traders as pekan and wejack.

In modern New England folklore, the fisher cat screams in the night, but the sound is almost always a fox or an owl. Popular writing long claimed the fisher flips a porcupine and eats its belly like a melon, a tale dismissed in 1966. Cameron Langford's novel Winter of the Fisher tells of a recluse who frees a trapped fisher and nurses it until it returns to the woods. A fisher hunts porcupines in the children's novel Ereth's Birthday, and one also turns up in The Sign of the Beaver. Conservationists now read the fisher's comeback as a mark of mature, connected forest.