Fisher

(Pekania pennanti)

Photo provided by the Mount Rainier National Park

The fisher, also known as the pekan, or erroneously called a fisher cat, is a forest-dwelling mustelid native to North America. A couple of names for the fisher are incredibly misleading, given they do not hunt fish and have no relation to cats.(1) It’s possible that “fisher” is derived from the word “fitch”, referring to the more familiar European polecat,(2) while the “cat” half is likely a superficial comparison to felines. The fisher was previously placed with the martens in genus Martes, until DNA analyses suggested a number of differences and evolutionary relations, and it was given its own genus, Pekania.(3)

Appearance

The fisher’s dorsal surface ranges from medium to dark brown—changing with the season and being slightly different between sexes, with males having coarser fur than females. The fisher’s coat is dense, glossy and dark brown to black in early winter. From the face to the shoulders, fur can be hoary-gold or silver due to tricolored guard hairs. The underside is almost completely brown, save for a cream-coloured chest patch varying in size and shape. During summer the fisher’s dorsal surface tends to be lighter.(2)

Habitat

Fishers are more likely to be found in old-growth forests, since trees in heavily logged areas with extensive second growth are not large enough to suit the denning requirements of female fishers.(4)

Behaviour

Fishers are most active at dawn and night. They are believed to be solitary animals that only associate when mating. Although fishers are arboreal like martens, they tend to spend most of their time on the forest floor and prefer coniferous forests, but they are also found in mixed and deciduous forests. They are likely to be found in areas with many hollow trees and continuous overhead cover, with greater than 80% coverage; avoiding areas with less than 50% coverage.(4)

Reproduction

Female fishers are sexually mature after one year of age, with breeding season lasting from late March to early April. After fertilization, blastocyst implantation is then delayed for ten months until mid-February of the following year. After gestating for about 36 days, the female gives birth of one to four kits.(5) Females then enter estrus seven to ten days later before the breeding cycle resumes.(6)

The kits are born blind and helpless, but begin to crawl after three weeks. They open their eyes about seven weeks later,(7) and start to climb after eight weeks. They will depend on their mother’s milk for the first eight to ten weeks of their lives, before being introduced to solid foods. After five months the mother will lead them out on their own, and after a year the juveniles will have established their own range.(6)

Diet

Despite their name, fishers seldom hunt fish. They mainly feed on small mammals, birds, insects, nuts, berries and carrion. Perhaps the most well known trait of the fisher is that they are one of few predators that hunt porcupines. Observational studies show that fishers make repeated biting attacks on the face of a porcupine and kill it after about 25–30 minutes.(4) This is in contrast to the dramatized rumor found in popular literature, where the fisher is said to flip a porcupine onto its back and “scoop out its belly like a ripe melon”.(8)

Natural predators

Although adult fishers are generally safe from predation, young fishers will occasionally fall prey to hawks, red foxes, lynx and bobcats.(9)

Fur trade

Since the 18th century, fishers have been popular with trappers due to the value of their fur. During the early 20th century, fishers were nearly exterminated due to a combination of overtrapping and changes to their habitat; especially in the northeastern United States. It wasn’t until 1934 when the fisher started to receive some form of protection. A few years of closed seasons helped the fisher make a gradual recovery of their former range, but once their numbers had improved, trapping resumed in the United States in the mid 1960s. Their numbers once again declined in the late 1970s, leading to a few more years of closed seasons. Trapping of fishers again resumed in 1979, but with restricted bag limits. Since then, their numbers have steadily increased.(3)(10)

Poisoning

In 2012, a study conducted by the Integral Ecology Research Center, UC Davis, U.S. Forest Service, and the Hoopa tribe showed that isolated populations of the fisher in California (also known as the Pacific fisher) are exposed to and killed by anticoagulant rodenticides associated with illegal marijuana cultivation.(11) Their study revealed that 79% of fishers tested in California were exposed to an average of 1.61 different anticoagulant rodenticides, with four fishers having died due to these toxicants. A follow-up study in 2015 determined that the fisher’s exposure and mortality from these toxicants increased to 85%, with a now exposed average of 1.73 different anticoagulant rodenticides, resulting in 9 more deaths.(12)

In 2017, Days Edge Productions released Forgotten but not Gone: The Pacific Fisher, to bring attention to the Pacific fisher’s struggles, and the controversial 2016 decision by the U.S. Fish and Wildlife to not list the species under the Endangered Species Act.

Despite their declining numbers, the Pacific fisher has yet to receive federal protection under the Endangered Species Act. On the 14th of May, 2020, the United States presidential administration denied Endangered Species Act protections to the Pacific fisher from Northern California to the Canadian border. They were however, granted endangered status in the southern Sierra Nevada.(13)

Interactions with domestic animals

In some areas, fishers will occasionally raid chicken coops. There have also been reports of fishers preying on domestic cats.(14)(15) Contrary to popular belief, cats are not on the fisher’s main menu. A 1979 study examined the stomach contents of fishers trapped in the U.S. state of New Hampshire, and discovered that cat hairs were found in only 1 of over 1,000 stomachs.(16)

Unless a fisher is threatened or cornered, attacks on humans are extremely rare. There has however, been a couple of isolated claims of attacks regarding children.(17) However, some of these claims are merely speculation, since the animal was not caught to confirm it was a fisher. Considering most people do not know what a fisher is or have ever encountered one before, it’s difficult to say if they were truly able to identify what they saw at a glance.

Fishers are simply trying to find food and survive, so to lower the chances of fisher attacks, it is recommended to restrict access to garbage, pets, pet foods, and domestic fowl.(18)

Range map

Body length: 90–120 cm / 35–47 in (males), 75–95 cm / 30–37 in (females)
Tail length: 37–41 cm / 14.5–16 in (males), 31–36 cm / 12–14 in (females)
Weight: 3.5–6.0 kg / 8–13 lb (males), 2.0–2.5 kg / 4–6 lb (females)
Lifespan: Up to 7 years (wild), up to 10 years (captivity)
Range: Northern forests of North America.
Conservation status: Least concern
References

  1. About FishersMass Audubon. Retrieved October 21, 2019.
  2. Roger A. Powell, Martes pennanti, Mammalian Species, Issue 156, 8 May 1981, Pages 4–6, https://doi.org/10.2307/3504050
  3. Koepfli, K., Deere, K.A., Slater, G.J. et al. Multigene phylogeny of the Mustelidae: Resolving relationships, tempo and biogeographic history of a mammalian adaptive radiation . BMC Biol 6, 10 (2008). https://doi.org/10.1186/1741-7007-6-10
  4. Powell, R. A. “The Fisher: Life History.” Ecology sity of Minnesota Press, Minneapolis MN (1993).
  5. Burt, William Henry. A field guide to the mammals: North America north of Mexico. Vol. 5. Houghton Mifflin Harcourt, 1976, p. 55.
  6. Feldhamer, George A.; Thompson, Bruce C.; Chapman, Joseph A. (2003).Wild mammals of North America: biology, management, and conservation. pp. 635–649. ISBN 978-0-8018-7416-1. Retrieved September 12, 2020.
  7. Pattie, Donald L.; Fisher, Chris C. (1999). Mammals of Alberta. Edmonton: Lone Pine Pub. p. 82.
  8. Doyle, Brian. “Fishering.” Ecotone 2.1 (2006): 1–2.
  9. Kurta, A. 1995. “Mammals of the Great Lakes Region”. Ann Arbor: University of Michigan Press.
  10. Novak, Milan. Furbearer harvests in North America, 1600-1984. Ministry of Natural Resources, 1987.
  11. Gabriel, Mourad W., et al. “Anticoagulant rodenticides on our public and community lands: spatial distribution of exposure and poisoning of a rare forest carnivore.” PloS one 7.7 (2012): e40163.
  12. Gabriel, Mourad W., et al. “Patterns of natural and human-caused mortality factors of a rare forest carnivore, the fisher (Pekania pennanti) in California.” PLoS One 10.11 (2015): e0140640.
  13. The Center for Biological Diversity “Trump Administration Denies Endangered Species Protection for Pacific Fisher Across Most of Species’ Range” (May 14, 2020) Retrieved June 08, 2020.
  14.  “Weasel-like fishers rebound; backyard pets become prey”. San Diego Union-Tribune. June 12, 2008. Archived from the original on October 9, 2011. Retrieved June 08, 2020.
  15. O’Brian, Brian (August 25, 2005). “On the wild side: Once nearly extinct, weasel-like fishers thrive in the suburbs, where their ravenous feeding habits threaten family pets”. Boston Globe. Retrieved June 08, 2020.
  16. Orff, Eric B. “The Fisher: New Hampshire’s Rodney Dangerfield”. New Hampshire Fish and Wildlife News. Retrieved June 08, 2020.
  17.  “Family says boy, 12, attacked by fisher cat”. WCVB News. July 1, 2014. Retrieved June 08, 2020.
  18. Rhines, C. 2003. “Martes pennanti” (On-line), Animal Diversity Web. Accessed September 12, 2020.

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