Fisher
Martes pennanti
Summary 3
The fisher (Martes pennanti) is a medium-sized mammal native to North America. It is a member of the mustelid family, commonly referred to as the weasel family. The fisher is closely related to the American Marten (Martes americana). A distinguishing factor between fishers and martens is the size. Fishers are much larger than martens. They have similar colorations, but fishers are much larger. The fisher is a forest-dwelling creature whose range covers much of the boreal forest in Canada to the northern fringes of the United States. Names derived from aboriginal languages include pekan, pequam, and wejack. This particular mammal is not found in Iron County, Utah.
Description 4
The Fisher is a forest-loving predator that eats anything it can catch, usually small-to-medium-sized rodents, rabbits, hares, and birds. It also eats carrion. Fishers are among the few predators able to kill Porcupines. They do it by biting the face, where there are no quills, until the animal is too weak to prevent being rolled over and attacked in the soft underbelly. Fishers are active by day or night. They tend to be solitary and defend territories. They were once hunted for their lustrous, chocolate-brown fur, and the range of this species has been reduced greatly in the United States. They are still hunted in some places, but some states and provinces of Canada list the fisher as endangered, and the population has recovered from extreme lows in the last century.
Links:
Mammal Species of the World
Click here for The American Society of Mammalogists species account
Distribution 5
Fishers are found only in North America, from the Sierra Nevada of California to the Appalachians of West Virginia and Virginia. They range along the Sierra Nevada to their southernmost extent and south along the Appalachian mountain chain. They do not occur in the prairie or southern regions of the United States. Populations have declined in the southern parts of their range in recent history.
Biogeographic Regions: nearctic (Native )More info for the terms: cover, natural
According to reviews, the fisher occurs from southern Yukon and southwestern Northwest Territories southeast through British Columbia and possibly extreme southeastern Alaska, Alberta, Saskatchewan, Manitoba, Ontario, southern Quebec, and New Brunswick to Nova Scotia. Its distribution extends south through several forested areas of the northeastern United States including Maine, New Hampshire, Vermont, northern New York, Pennsylvania, western Massachusetts, the upper peninsula of Michigan, and northern Wisconsin and Minnesota. There is also a population in West Virginia. In the western United States, fisher populations are known to occur in western Montana, the Idaho panhandle [94,96,97], the southern Sierra Nevada of California, the Klamath and Siskiyou mountains of northwestern California and extreme southwestern Oregon, and the southern Cascade Range of southwestern Oregon [14,136]. The fisher may be extirpated from Washington [14,118]. For more detailed summaries of the fisher's historic and current distribution, see these sources: [94,96,97]. For a map of the fisher's current and historic distribution, search the National Museum of Natural History's Mammal Species of the World website for fisher.
The following lists are speculative. They are based on distribution information reported no earlier than 1993 and the habitat characteristics and species composition of communities fishers are known to occupy. There is not conclusive evidence that fishers occur in all the habitat types listed, and some community types may have been omitted, especially in areas where fishers have not been recently documented. In addition, the following cover types provide habitat of varying quality for fishers. See Preferred Habitat for more detail.
Food habits 6
Fishers are predators, and most of their prey are plant-eating mammalia. Fishers eat muridae, erithizon dorsatum, sciuridae, lepus americanus, aves, and soricidae, and sometimes, other carnivora. They may also feed on fruits and berries, such as beechnuts and apples.
They have also been seen to eat odocoileus virginianus, though they are most likely scavenging a deer carcass.
Fishers and martes americana are the only medium-sized predators agile in trees that also have the ability to stretch themselves to look for prey in holes in the ground, hollow trees and other small areas. Fishers are hunt alone, and look for prey that is their own size or smaller, although they are capable of taking on prey larger than themselves.
Animal Foods: birds; mammals
Plant Foods: fruitMore info for the term: frequency
Fishers are generalist predators. Their diets are comprised predominantly of snowshoe hares, North American porcupines (Erethizon dorsatum), small mammals, birds, carrion, and/or plants. Snowshoe hares are important prey throughout much of the fisher's range [40,108,130]. Snowshoe hares occurred in 39% of 215 fisher stomachs collected in British Columbia in winter [130] and 28% of 242 fisher digestive tracts collected in Maine from September to April [40]. North American porcupines are another often preyed-upon species [10,98,130]. North American porcupines occurred in 21% of 69 fisher scats collected Maine in winter [10] and 19.5% of 215 stomachs collected in British Columbia in winter [130]. Fishers prey on several small mammals including squirrels, shrews (Soricidae), voles, and mice (Muridae) [66,98,108,124,134]. Of 215 stomachs collected in British Columbia from November to February, 33.5% contained red squirrels (Tamiasciurus hudsonicus), 14.9% contained shrews, 23.3% contained southern red-backed voles (Clethrionomys gapperi), and 15.8% contained deer mice (Peromyscus maniculatus) [130]. Squirrel remains were found in 20.4% of 201 scats collected year-round in the southern Sierra Nevada and included western gray squirrels (Sciurus griseus), Douglas's squirrels (Tamiasciurus douglasii), and northern flying squirrels (Glaucomys sabrinus) [134]. Birds found in stomach contents or scats include Passeriformes [124], Galliformes [10,124,130], and Falconiformes [98]. Fishers also eat carrion, typically from ungulates such as deer (Odocoileus spp.) [10,98,124,130,134] and moose (Alces alces) [130]. American martens and fishers occur in fisher diets [65,130]. It not certain whether the fishers were preyed on or scavenged [130]. Common muskrats (Ondatra zibethicus) [10,124,130], northern raccoons (Procyon lotor) [10,98,124], reptiles (Reptilia), insects (Insecta), [124,134], and several genera of fungi [134] have been found in fisher scats or stomach contents. Fishers also eat plant material, including apples (Malus spp.) [10,124], common winterberries (Ilex verticillata) [10,98], manzanitas (Arctostaphylos spp.), currents (Ribes spp.) [134], black cherries (Prunus serotina), serviceberries (Amelanchier spp.), and blueberries (Vaccinium spp.) [98]. Willson [131] reviews fruits eaten by mammals including the fisher.
In some areas there are differences in diet between age classes and gender. For instance, in Massachusetts and New Hampshire juvenile fishers ate significantly more northern raccoons (P=0.002) than adult fishers, and females ate significantly (P=0.006) more eastern gray squirrels (Sciurus carolinensis) than males [98]. The stomachs of female fishers collected in British Columbia had significantly (P≤0.04) higher occurrence of small mammal remains than males [130], and in New Hampshire significantly (P<0.01) more males contained North American porcupine quills [66]. However, no significant differences in diet were observed between the sexes in Maine (P>0.1) [40] or Vermont (P=0.883). Adults and juveniles also had similar diets in Vermont (P=0.836) [124].
Fishers are likely capable of changing diets with changing availably of prey. For instance, in Massachusetts and New Hampshire fisher diets changed with the seasons. Fruits were common in summer and early autumn, while northern raccoons and eastern gray squirrels were common prey in winter. In addition, birds were not detected in the diets of fishers in the early autumn or winter [98]. There was a significant (P<0.1) shift in diet composition from autumn to spring in Maine, with snowshoe hare and white-tailed deer (Odocoileus virginianus) increasing and shrews decreasing in frequency as the winter progressed [40]. In Ontario, fishers displayed a delayed positive response to lagomorph (Lepus americanus and Sylvilagus floridanus) abundance, but appeared to use alternate prey during a period of low lagomorph abundance [27]. In northern Minnesota, predation of small mammals was negatively associated with predation of snowshoe hares for male and female fishers (P<0.02), suggesting the importance of small mammals during snowshoe hare population declines [73].
Reviews of fisher diet [82,97], hunting behavior [94,97], and ecological energetics [94] are available.
Geographic range 7
Fishers are found only in North America, from the Sierra Nevada of California to the Appalachians of West Virginia and Virginia. They range along the Sierra Nevada to their southernmost extent and south along the Appalachian mountain chain. They do not occur in the prairie or southern regions of the United States. Populations have declined in the southern parts of their range in recent history.
Biogeographic Regions: nearctic (Native )More info on this topic.
This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):
BLM PHYSIOGRAPHIC REGIONS [25]:
1 Northern Pacific Border
2 Cascade Mountains
4 Sierra Mountains
8 Northern Rocky Mountains
Habitat 8
Fishers prefer coniferous forests, but they are also found in mixed and deciduous forests. They prefer habitats with thick canopies. They also prefer habitats with many hollow trees for dens. Trees typically found in fisher habitats include spruce, fir, white cedar and some hardwoods. Also, as would be expected, their habitat preference reflects that of their favored prey species.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: taiga ; forest ; mountains
Physical description 9
Male fishers are, on average, larger than females, with a body length of 900 to 1200 mm and a body weight of 3500 to 5000 grams. Females range from 750 to 950 mm in length and 2000 to 2500 grams in weight. Tail length of males is between 370 and 410 mm and tail length of females is between 310 and 360 mm. Their coats range from medium to dark brown, with gold to silver hair tips on their head and shoulders, and with black legs and tail. They may also have a cream chest patch of variable size and shape. Fur color and pattern varies among individuals, sexes and seasons. Fishers have five toes on their feet, and their claws can be drawn up into the paws, like a cat's.
Range mass: 2000 to 5000 g.
Range length: 750 to 1200 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Tracks 10
The front print has a size range of 5.4-9.8 centimeters in length and 4.8-10.8 centimeters in width. These tracks will be plantigrade and are asymmetrical. The first toe is the smallest and is located on the inside of the track. The space between the toes and the metacarpals is usually filled with fur, which can be used to distinguish it from other mammals. The claws may or may not register.
The back print has a size range of 5.1-7.9 centimeters in length and 3.8-8.8 centimeters in width. These tracks will be plantigrade and asymmetrical as well. The furred heel often registers, which helps as a distinguishing factor.
Scat 10
The size of the scat has a range of 0.5-1.9 centimeters in diameter and 5.1-17.8 centimeters in length. They do not often mark on the trails, but they mark all sorts of elevated surfaces. They often will leave their scat where other mammals have left their's. Fisher scats accumulate at dens.
Sources and Credits
- (c) Claire H., some rights reserved (CC BY-SA), http://www.flickr.com/photos/8435962@N06/3388194120
- (c) madilynnehring, all rights reserved
- Adapted by madilynnehring from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Martes_pennanti
- (c) Smithsonian Institution, some rights reserved (CC BY), http://eol.org/data_objects/6625046
- Adapted by madilynnehring from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31405044
- Adapted by madilynnehring from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065529
- Adapted by madilynnehring from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065523
- Adapted by madilynnehring from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065524
- Adapted by madilynnehring from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065525
- (c) madilynnehring, some rights reserved (CC BY-SA)
