Neovison visonAmerican mink

Geographic Range

Mink are found throughout the United States, appearing in parts of every state except Arizona. They are also present in most of Canada, including an introduced population on Newfoundland. Only along the Arctic coast and some offshore islands are they absent.

American mink have also been inadvertently introduced to the British Isles, where they escaped from fur farms in the 1960's. As a non-native predator their effects on native wildlife there are serious.

Habitat

Although mink are found throughout North America, they tend to frequent forested areas that are in close proximity to water. Streams, ponds, and lakes, with some sort of brushy or rocky cover nearby are considered optimal territory. (Kurta, 1995)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams
  • coastal

Physical Description

Mink fur is usually dark brown with white patches on the chin, chest, and throat areas. The fur is soft and thick, with oily guard hairs that waterproof the animal's coat (Chapman and Feldhamer 1982). The body is long and slender with short legs and a pointy, flat face. The toes are partially webbed, showing the mink's semi-aquatic nature. Body length is usually around 2 feet or 610 mm (Van Gelder 1982) with up to half of this length being the tail. Females, on average, are substantially smaller than males. Adult females weigh between 0.7 to 1.1 kg, while males range from 0.9 to 1.6 kilograms (Chapman and Feldhamer 1982). Body length varies as well, with males measuring from 580 to 700 mm and females from 460 to 575 mm (Chapman and Feldhamer 1982). (Chapman and Feldhamer, 1982; Van Gelder, 1982)

  • Sexual Dimorphism
  • male larger
  • Range mass
    700 to 1600 g
    24.67 to 56.39 oz
  • Range length
    460 to 700 mm
    18.11 to 27.56 in
  • Average length
    610 mm
    24.02 in

Reproduction

During the winter, female mink become fertile and mate with one or more males (who are also promiscuous).

Both males and females begin mating at ten months (Chapman and Feldhamer 1982). Once a female is impregnated, her gestation period varies from 40 to 75 days (Kurta 1995). The young are born in late spring (April or May), with litter sizes usually ranging between 1 to 8 individuals (Chapman and Feldhamer 1982). Each newborn weighs 8 to 10 grams and appears pink and wrinkled, with a thin coat of white fur covering the body. (Chapman and Feldhamer, 1982; Kurta, 1995)

  • Breeding interval
    Breeding occurs once yearly.
  • Breeding season
    Mating occurs during the winter months.
  • Range number of offspring
    1 to 8
  • Range gestation period
    40 to 75 days
  • Average weaning age
    6 weeks
  • Range time to independence
    6 to 10 months
  • Average age at sexual or reproductive maturity (female)
    10 months
  • Average age at sexual or reproductive maturity (male)
    10 months

The young open their eyes at three and a half weeks and are weaned at a month and a half (Van Gelder 1982). They remain with the mother through the summer until fall, when they leave to establish their own territories. (Van Gelder, 1982)

  • Parental Investment
  • altricial
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

The maximum lifespan for a mink is usually around 10 years. (Kurta, 1995)

  • Typical lifespan
    Status: wild
    10 (high) years

Behavior

Mink are primarily solitary animals, with males being particularly intolerant of one another. They mark the boundaries of their home range using musky secretions from enlarged anal glands. They are mostly active at night, especially near dawn and dusk. Mink are also skilled swimmers and climbers. In searching for food, they can swim up to 30 meters (100 feet) underwater and dive to depths of 5 meters (Kurta 1995). Mink dig their burrows in the banks of rivers, lakes and streams, or they may utilize the old dens of other mammals, such as muskrats. Mink may line the interior of their home with dried grass and leaves, as well as with the fur from past prey. (Kurta, 1995)

Communication and Perception

Mink communicate using a variety of cues, including chemical, visual, and auditory signals. They are fairly quiet, but rely heavily on chemical signaling for communicating territorial boundaries and reproductive status.

Mink have excellent senses of vision, smell, and hearing.

Food Habits

The diet of mink varies with the season. During the summer it consists of crayfish and small frogs, along with small mammals such as shrews, rabbits, mice, and muskrats. Fish, ducks and other water fowl provide additional food choices. In the winter, they primarily prey on mammals.

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
  • Animal Foods
  • birds
  • mammals
  • amphibians
  • reptiles
  • fish
  • aquatic crustaceans

Predation

Mink have few natural enemies. They are occasionally killed by coyotes, bobcats and other carnivores, but their main threat remains humans. Mink, like most mustelids, are aggressive and fearless predators. They do not hesitate to defend themselves against animals larger than themselves. Mink may be occasionally taken by birds of prey, or young in a nest may be taken by snakes, but they are agile, cryptic in coloration, and secretive in nature, thereby avoiding most predation. (Kurta, 1995)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Mink are important predators of small mammals throughout their range.

Economic Importance for Humans: Positive

Mink pelts have for years been considered one of the most luxurious furs on the market. Originally all fur came from natural populations, causing a severe strain on the species. However, starting in the mid 1900s, mink ranches were established to help bring a more consistent pelt supply to the market. Ranching was very successful, with the number of mink ranches in the United States reaching a high of 7200 during the mid-1960s (Chapman and Feldhamer 1982). While the number of ranches has declined nationally to 439 (1998), a total of 2.94 million pelts were still produced (both wild and domestic mink), that were valued at $72.9 million dollars (USDA 1999). The quality of a pelt, which significantly affects the price, is determined by its size, color, texture and density. ("National Agricultural Statistics Service: Mink", July 22, 1999; Chapman and Feldhamer, 1982)

  • Positive Impacts
  • body parts are source of valuable material

Economic Importance for Humans: Negative

The only negative affects that can be attributed to mink is the possible competition between mink and humans for water fowl or other game species.

Conservation Status

The main threat towards mink survival is the continued existence of the fur market. Forty-seven states and all Canadian provinces currently conduct limited trapping seasons on mink, with the length of the season varying from area to area (Chapman and Feldhamer 1982). Quotas on catch size have also been set in many places. Both of these tactics allow the limited removal of mink in order that population densities will remain constant.

Another threat includes the destruction of mink habitat. Mink depend heavily on aquatic areas. Creating, enhancing, and maintaining such habitat allows for the continued existence of healthy populations throughout the range of the species (Chapman and Feldhamer 1982).

The presence of environmental contaminants such as mercury and hydrocarbon compounds (e.g., DDT and PCBs) pose an additional threat to mink (Kurta 1995). These chemicals accumulate within the mink's tissues and can cause problems in reproduction or even threaten the animal's life. Closer regulation over the use and disposal of these chemicals is necessary. (Chapman and Feldhamer, 1982; Kurta, 1995)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Allison Poor (editor), University of Michigan-Ann Arbor.

Kurt Schlimme (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

taiga

Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5? N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

July 22, 1999. "National Agricultural Statistics Service: Mink" (On-line). Accessed Oct. 14, 1999 at http://usda.mannlib.cornell.edu/reports/nassr/other/zmi-bb/mink0799.txt.

Chapman, J., G. Feldhamer. 1982. Wild Mammals of North America. Baltimore and London: The Johns Hopkins University Press.

Kurta, A. 1995. Mammals of the Great Lakes Region. Ann Arbor, MI: The University of Michigan Press.

Van Gelder, R. 1982. Mammals of the National Parks. Baltimore, MD: The Johns Hopkins University Press.