American mink (Neovison vison)

Also known as: eastern mink, New World mink, North American mink
Synonyms: Lutra vison, Mustela canadensis, Mustela rufa, Mustela vison, Vison lutreola
KingdomAnimalia
PhylumChordata
ClassMammalia
OrderCarnivora
FamilyMustelidae
GenusNeovison (1)
SizeMale head-body length: 33 - 43 cm (2)
Female head-body length: 30 - 40 cm (2)
Male tail length: 15.8 - 23 cm (2)
Female tail length: 12.8 - 20 cm (2)
Male weight: 681 - 2,310 g (2)
Female weight: 790 - 1,089 g (2)
Top facts

The American mink is classified as Least Concern (LC) on the IUCN Red List (1).

The American mink (Neovison vison) is a medium-sized, semi-aquatic mustelid with a long, slender body and relatively short legs (3) (4). Its tail is less than half the length of its head and body (2) (3) (5) (6), and its short, rounded ears barely project above its fur (2) (5).

The American mink’s fur is soft and luxurious (2), with a thick, warm layer of underfur and longer, oily guard hairs which make the coat water-resistant (5). The feet are fully furred, except for on the toe tips and pads, and the toes are webbed at the base (5). The American mink’s glossy fur is usually dark brown to black, often with white patches on the chin and throat and sometimes also white spots on the chest and belly (2) (4) (5) (6). However, this species has been selectively bred in captivity and many different colour variations have been produced (2) (3) (4) (5). These colour variations can sometimes be seen in escaped, feral individuals, and can range from white to grey, yellowish-brown or black (3).

Although the male and female American mink are similar in appearance, the male is usually slightly larger and heavier than the female (4) (5). A number of subspecies of American mink have been described (5).

In parts of Europe, where the American mink is an introduced, non-native species, it can easily be confused with the native European mink (Mustela lutreola). However, the European mink can generally be distinguished by its smaller size and by the more extensive white patch on its upper lip (4) (5) (7).

As its common name suggests, the American mink is native to North America, where it occurs from Alaska and Canada south through most of the United States, except for dry parts of the southwest (1) (2) (5) (7).

The American mink is highly prized for its fur, and has been introduced or has escaped from fur farms in a number of countries outside of its native range. This species has now established wild populations in Russia and many parts of Europe, including the United Kingdom and Ireland. The American mink also now occurs in the wild in Iceland, China and Japan, and feral populations have been reported from parts of South America, including Chile and Argentina (1) (3) (5) (7) (8).

The American mink is usually associated with water, being found along streams, rivers, lakes, marshes and swamps (2) (3) (4) (7), and also inhabiting coastlines (4) (5) (7). However, this species also occurs in drier areas away from water and even in urban areas if food is abundant (3) (4) (5) (7). The American mink tends to prefer habitats with dense vegetation (2), which provides it with plenty of cover (3).

The American mink is usually nocturnal, although it may sometimes also be active during the day (2) (5). Although it is an excellent swimmer and can dive to depths of five to six metres (2) (5), this species is thought to be only partially adapted to an aquatic lifestyle and does not have the underwater endurance needed to pursue prey in open water (5). The American mink is a skilled tree climber and can jump from tree to tree as well as being able to descend from trees head first (5).

A voracious and opportunistic predator, the American mink takes a variety of prey, including small mammals, fish, amphibians, birds, crayfish, crabs, insects and worms (2) (3) (4) (5). The exact composition of the diet depends on the location and season, and the American mink may also opportunistically hunt rabbits, squirrels, reptiles, bats and snails, as well as sometimes eating carrion. This species can be a significant predator of waterfowl and their eggs (5). The American mink often kills more prey than it can eat, storing the surplus to feed on later (3) (5).

The American mink is usually solitary and marks its territory with pungent secretions from anal scent glands (2) (5). It is also able to empty the contents of these glands under stress, possibly as a form of defence (5). This species sometimes digs its own burrows in which to shelter, but it more commonly uses abandoned muskrat or beaver houses, the burrows of other small mammals, or builds a den among tree roots, stones or brush piles (2) (3) (5). Its dens often have more than one entrance and are typically located close to water (2) (5).

Mating in this species occurs in the spring, usually between February and April, with births taking place in April, May and June (2) (4) (5). The female American mink shows delayed implantation, with the fertilised eggs not implanting in the uterus or developing straight away. Therefore, although the actual development of the embryo only takes 30 to 32 days (2) (5), the overall gestation period may last for 39 to 78 days (2), becoming shorter with increased temperatures (4) (5).

The female American mink gives birth to a single litter of two to ten young each year (2), although four or five young is more typical (2) (5). The young are born in a nest lined with fur, feathers and dry plant material (2), and are blind, naked and helpless at birth (2) (5). Their eyes open at four to five weeks old and they are weaned at five to six weeks. Young American mink begin to hunt at about eight weeks old, but remain with the adult female until the autumn (2) (5).

Female American mink reach sexual maturity at about 12 months old, but males are not mature until they are around 18 months old (2) (3). This species can potentially live for eight to ten years in captivity (2) (4) (5), but three to four years is more typical in the wild (2) (4) (5) (7). Potential predators of the American mink include birds of prey, owls, foxes, coyotes, lynx and otters (5) (7).

The American mink has a large distribution and a stable population and is not currently considered to be under threat, although some populations may be affected by the alteration of wetland habitats and by water pollution (1). Individuals may also sometimes be killed on roads or by accidental capture in fish cages or gill nets (5). One subspecies of the American mink in southern Florida appears to be quite rare and may potentially be threatened by water diversion projects (2).

This species has been prized for its luxurious fur, and some hunting of wild individuals still occurs (1). However, most mink fur is now produced on mink farms, and the American mink is the most important species in fur-farming operations (1) (2) (5). Escapes from fur farms have been common, and farmed mink have also been deliberately released by animal rights activists or intentionally introduced to new areas to be harvested for their fur (3) (4) (6) (7).

As an adaptable and successful predator, the American mink can have serious impacts on native wildlife outside of its natural range. As well as preying on native species, it may also compete with native predators such as otters (Lutra lutra) and European mink (M. lutreola) (3) (4) (5) (7), and can potentially act as a vector of disease (3) (4) (7). By killing and storing more prey than it can eat, a single mink can have large impacts on prey populations, and can decimate entire colonies of waterbirds (3) (4) (9).

The American mink has been implicated in dramatic declines in the water vole (Arvicola amphibius) population in the UK, as well as in declines of ground-nesting birds (3) (4) (7) (8) (9). It is also thought to be negatively affecting the highly threatened European mink (3) (4) (5) (7) as well as native polecat populations (3) (4) (8). In addition to having negative impacts on wildlife, the American mink can also pose a problem by killing domestic poultry and causing damage to fisheries (3) (4) (7) (8).

American mink that have escaped from fur farms can also pose a threat to the species’ wild populations in its native range. For example, studies in parts of Canada have found large numbers of domestic mink and their descendents living in the wild, and it is feared that these will compete with and may introduce diseases to the wild population. Interbreeding between wild and domestic American mink could also lead to ‘domestic’ genes being introduced into the wild population. These genes may not be well adapted to the local natural environment, so could reduce the wild population’s ability to survive (10).

There are no specific conservation measures currently in place for this widespread and successful mammal. Where the American mink has been introduced outside of its natural range, a number of control measures are in place to try and reduce its impacts on native wildlife. For example, eradication attempts have been made in the Outer Hebrides, off the coast of Scotland (3) (4) (7) (8), and the American mink can be legally hunted in some European countries (4). However, total eradication of this species is not always feasible (3) (8), and the success of eradication attempts has varied (4) (8). In the American mink’s native range, identifying and removing feral individuals would be even more complicated (10).

Although it may not be possible to remove the American mink from all of its non-native range, certain measures may help to reduce its impacts on native species. For example, it is thought that an increase in otters can lead to a decrease in American mink, so helping otter numbers to recover would help to keep mink numbers down (3) (8) (11). Vulnerable native species can also benefit from habitat restoration and management that provides them with suitable refuges from mink (8). Local control campaigns can also help to keep mink numbers in check (8), while mink-proof fences and various repellents may be used to exclude mink from sensitive areas (3).

To reduce the spread of the American mink, it will be important to prevent further escapes from fur farms. In the UK, all fur farms have now closed (7), and it is an offence to release the American mink into the wild or to allow it to escape (6). In Estonia, bringing this species into the country for captive breeding is banned, and there are plans to make conditions for existing farms very strict (4). In countries not yet invaded by the American mink, it will be important to prevent mink farms from being established. Where farms are already present, improved measures are needed to prevent mink from escaping, and rapid detection and action will be necessary for any that do make it into the wild (8) (10).

Although its numbers are increasing worldwide, the American mink appears to now be declining in a few European countries, including Sweden and the UK (7) (8). The reasons for this are largely unknown (8), and there is a lack of detailed information on the size, extent and impacts of the American mink population in many countries in its non-native range (3) (8). Monitoring programmes have been recommended so that this species’ introduced populations can be better understood and controlled (4).

Find out more about the American mink:

More information on the American mink as an invasive species:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

  1. IUCN Red List (October, 2013)
    http://www.iucnredlist.org/
  2. Nowak, R.M. (1991) Walker’s Mammals of the World. The Johns Hopkins University Press, Baltimore and London.
  3. Invasive Species Compendium: Datasheets - Neovison vison (American mink) (October, 2013)
    http://www.cabi.org/isc/?compid=5&dsid=74428&loadmodule=datasheet&page=481&site=144
  4. NOBANIS: Invasive Alien Species Fact Sheet - Neovison vison (October, 2013)
    http://nobanis.org/files/factsheets/Neovison_vison_final.pdf
  5. Larivière, S. (1999) Mustela vison. Mammalian Species, 608: 1-9. Available at:
    http://www.science.smith.edu/msi/pdf/i0076-3519-608-01-0001.pdf
  6. GB Non-native Species Secretariat (NNSS): Identification Sheet - American mink (October, 2013)
    https://secure.fera.defra.gov.uk/nonnativespecies/index.cfm?sectionid=47
  7. GB Non-native Species Secretariat (NNSS): Factsheet - American mink (October, 2013)
    https://secure.fera.defra.gov.uk/nonnativespecies/factsheet/factsheet.cfm?speciesId=2272
  8. Bonesi, L. and Palazon, S. (2007) The American mink in Europe: Status, impacts, and control. Biological Conservation, 134(4): 470-483.
  9. Craik, C. (1997) Long-term effects of North American mink Mustela vison on seabirds in western Scotland. Bird Study, 44: 303-309.
  10. Kidd, A.G., Bowman, J., Lesbarrères, D. and Schulte-Hostedde, A.I. (2009) Hybridization between escaped domestic and wild American mink (Neovison vison). Molecular Ecology, 18: 1175-1186.
  11. Bonesi, L. and Macdonald, D.W. (2004) Impact of released Eurasian otters on a population of American mink: a test using an experimental approach. Oikos, 106: 9-18.