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.
- Biogeographic Regions
- nearctic
- palearctic
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.
- Habitat Regions
- temperate
- terrestrial
- Terrestrial Biomes
- taiga
- savanna or grassland
- forest
- Aquatic Biomes
- lakes and ponds
- rivers and streams
- coastal
- Wetlands
- marsh
- Other Habitat Features
- riparian
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).
- Other Physical Features
- endothermic
- homoiothermic
- bilateral symmetry
- Sexual Dimorphism
- male larger
Reproduction
During the winter, female mink become fertile and mate with one or more males (who are also promiscuous).
- Mating System
- polygynandrous (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.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- viviparous
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.
- Parental Investment
- altricial
-
pre-fertilization
-
protecting
- female
-
protecting
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-independence
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
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.
- Key Behaviors
- terricolous
- natatorial
- nocturnal
- motile
- sedentary
- solitary
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.
- Other Communication Modes
- scent marks
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.
- 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.
- 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.
Additional Links
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.
- 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.
- introduced
-
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- Palearctic
-
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
- introduced
-
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
- 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.
- 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.
- 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.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- coastal
-
the nearshore aquatic habitats near a coast, or shoreline.
- marsh
-
marshes are wetland areas often dominated by grasses and reeds.
- riparian
-
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
- 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.
- 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.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- 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).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- 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.
- natatorial
-
specialized for swimming
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- solitary
-
lives alone
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- scent marks
-
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- 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.
- carnivore
-
an animal that mainly eats meat
References
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.
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 .