Fisher

(Pekania pennanti)

Photo provided by the Mount Rainier National Park

The fisher is a forest-dwelling mustelid native to North America. The fisher is unfortunately another mustelid whose name tends to be misspoken as a compound of another species. They are often misleadingly called “fisher cats”, when they have no relation to felines.(1) 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.(2)

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.(3)

Habitat

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) 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.(5)

Diet

Its name is misleading, given that the animal seldom hunts fish. However, it’s possible that ”fisher” is derived from the French word ”fichet”, which means ”ferret”.(3) The fisher mainly feeds on small mammals, birds, insects, nuts, berries and carrion. Perhaps the most well known trait of the fisher is that it is 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.(6) This is in contrast to the exaggerated misconception found in popular literature that they can flip a porcupine onto its back and “scoop out its belly like a ripe melon”.(7)

Size: 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 (females)
Weight: 3.5–6.0 kg / 8–13 lb (males), 2.0–2.5 kg / 4–6 lb (females)
Lifespan: 3–4 years
Range: Northern forests of North America
Conservation status: Least concern
References

  1. About FishersMass Audubon. Retrieved September 2,2018.
  2. Koepfli, Klaus-Peter, et al. “Multigene phylogeny of the Mustelidae: resolving relationships, tempo and biogeographic history of a mammalian adaptive radiation.” BMC biology 6.1 (2008): 10.
  3. Powell, Roger A. “Martes pennanti.” Mammalian Species 156 (1981): 1-6.
  4. Powell, p. 88.
  5. Powell, p. 92.
  6. Powell, pp. 134–6.
  7. Doyle, Brian. “Fishering.” Ecotone 2.1 (2006): 1-2.

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