American Mink

(Neovison vison)

American mink in summer coat by Anna Wójtowicz
Alternate winter coat: Link

American mink, also known as North American mink, are native to North America, but can be found introduced in several continents. American mink and their recently extinct cousin the sea mink († Neovison macrodon) are generally considered the only “true” species of mink. This is because the so-called European mink is actually a semi-aquatic polecat, being much closer related to the European polecat and steppe polecat.(1)(2) The American mink was once considered a weasel of the genus Mustela, but in the late 1990s their Latin name was changed to Neovison.(3)

Appearance (non-feral)

Relatively slim, but the face in particular has blunt and boxy features. The eyes are small and the nose is large in comparison, emphasized by prominent whisker pads that gives the mink an otter-like quality. The long and dense fur hides most the ears and emphasizes the robust anatomy. Their paws are partially webbed and more sparsely furred than the rest of the body; supporting their semi-aquatic nature.

The fur is usually chocolate to reddish brown in colour, decorated with white patches on the chin, chest, or throat. It is smooth and thick in structure, with oily guard hairs that waterproof the coat.

Winter coat

The winter coat tends to be longer, denser, silkier and darker than the summer coat. The coat does not turn white for winter.

Habitat

The American mink dwells in forested areas near rivers, streams, lakes, ponds and marshes.

Behaviour (non-feral)

American mink are mostly nocturnal and solitary animals, with males being particularly intolerant of one another. There is however, extensive overlap in territories between the opposite sex. Their home ranges are usually 1–6 kilometres (0.62–3.73 miles) long, with male territories larger than females’.(4) Like most mustelids, American mink use their enlarged anal glands to mark the boundaries of their territories.

American mink will dig their burrows in river banks, lakes and streams; also holes under logs, tree stumps, or in roots and hollow trees. They will at times use abandoned dens of other mammals, such as badgers, skunks and muskrats. Sometimes dens located in rock crevices, drains, and nooks under stone piles and bridges are also chosen. The burrows that they dig themselves are usually four inches in diameter, and may continue along for 300–370 cm (10–12 feet) at a depth of 61–91 cm (2–3 feet).(5) These burrows are characterised by numerous entrances and twisting passages, consisting of one to eight exits.(6) They will occasionally line the interior of their den with dried grass and leaves, or fur from past prey.(7) American mink are also excellent swimmers, and have been reported to swim 30 meters (100 feet) underwater, and dive to depths of 5 meters (16 feet).(8)

Reproduction

Mating season ranges from February in the southern range, and to April in the north, and lasts for three weeks. The mating process is aggressive, with males typically biting the nape of the female’s neck and pinning her with his forepaws. Mating can last anywhere from 10 minutes to four hours. Once a female is impregnated, the gestation period last from 40 to 75 days. The young are born from April to June, with litters consisting of four kits on average. The kits are blind at birth. They depend on their mother’s milk for five weeks, and begin hunting after eight weeks of age. They do not become fully independent until autumn. Sexual maturity is reached the following spring at about 10 months old.(9)

Diet

The diet of American mink varies by season and region. During the summer they consume crayfish and small frogs, as well as smaller mammals such as shrews, rabbits, mice, and muskrats. Fish, ducks and other water fowl provide additional food choices.(8) In British Isles, European rabbits are common summer prey, while European hares are preyed on occasionally.(10) In South America’s Cape Horn Biosphere Reserve, several native and exotic mammals are the American mink’s main prey.(11)

Surplus killing

The American mink will occasionally exhibit surplus killing behaviour when presented with an abundance of food. However, surplus food is often carried to a den to be cached for later consumption.(12) This is more beneficial during the winter months when carcasses do not spoil as quickly. It is possible that surplus killing in the American mink is an evolutionary response to unpredictable food resources;(13) never knowing when their next meal is coming along.

Predators

Although adult American mink can generally defend themselves, their young can fall prey to bobcats, coyotes, wolves, and birds of prey.(8)

Bloodsucking and blood-drinking myth

The American mink does not “suck” the blood of its prey. This is a common misconception that has been applied to several mustelid species, none of which have the necessary jaw muscles to be physically capable of sucking blood. Some argue that American mink are capable of sucking blood because they draw milk from their mother when unweaned, however, this is called “suckling”, which is a completely different reflex from “sucking”. They are also not hematophagous and do not indulge in drinking blood.

Both of these myths are likely a construct of what some people heard or thought they saw, rather than what actually happened. Following an event of surplus killing, seeing uneaten animals with teeth marks left in their necks or skulls may have given rise to the myth that their blood was simply “sucked out” by the mink. Even if they could suck blood, this would serve the animal little dietary benefit, since consuming meat is far more important.

Introduced range and fur farming

The American mink’s fur has been highly prized for use in clothing, with hunting giving way to fur-farming. Their treatment on fur farms has been a focus of animal rights and animal welfare activism.(14) According to the Game & Wildlife Conservation Trust, there is a modern misconception that Britain’s feral American mink originated from mass releases by wildlife activists in the 1990s, when in actuality the wild population was established decades earlier.(15)

Between the 1920s and 1950s, American mink were imported from North America to Europe, the USSR, and southern South America to stock fur farms. In parts of Europe, escaped and released farmed American mink have established self-sufficient feral populations, and have been classified as an invasive species linked to the decline of the European mink,(16)(17) as well as other small mammals and birds. Pejorative humanisations of the American mink by the public remain chronic. Nevertheless, we cannot shift all the blame onto the American mink for this ecological disruption, since they were willfully introduced to the continent, despite the reasonably foreseeable consequences from possible escapes or releases.

The American mink was once blamed for the decline of the Eurasian otter population in Great Britain.(18) Further studies revealed that during the mid-20th century, many otters were dying from dieldrin poisoning; a organochlorine insecticide used by farmers.(19) Dieldrin was withdrawn from use in 1962 and eventually banned in 1989.(20)

Colour mutations

Selective breeding of farmed American mink (also referred to as domestic mink) have resulted in a range of colours from beiges, greys, and to a brown that is almost black.(21) They are often portrayed as pure white in visual media, but this colour too (unless born albino) is usually only seen in farmed mink. The American mink’s natural fur colour is brown.

Decline of wild American mink

Due to large numbers of domestic American mink escaping or being released from fur farms and establishing themselves in the wild, conservationists believe that wild American mink populations in North America are not only threatened by disease and competition for resources with domestic American mink, but also by hybridising with them.(22)

Both types of mink are solitary and territorial, and overpopulation often results in the animals killing each other through direct conflict, or by causing weaker mink to be driven from their territory until starvation sets in. Too many domestic mink escaping into the wild can flood the ecosystem, and cause disruption; resulting in not only the deaths of the majority of the feral mink, but as well as many of the wild ones from starvation or injuries incurred while fighting over territory.(23) If a domestic American mink manages to survive long enough to reproduce, it may lead to problems for the wild American mink, since adding weaker domestic genes to wild populations can also contribute to their decline.(22) Some researchers believe this is a contributing factor for the decline of wild American mink in Canada.(24)

SARS-CoV-2 outbreaks on mink farms

American mink are susceptible to SARS-CoV-2 (the virus that causes COVID-19) infection, and there have been numerous outbreaks reported on mink farms in Europe and North America. [Further reading on this subject…]

Use in hunting (minkenry)

If properly trained during their youth, American mink can make excellent hunting companions, as demonstrated by Joseph Carter “The Mink Man” on his YouTube channel.

Geographic range

Body length: 34–45 cm / 13–18 in (males), 31–37.5 cm / 12–15 in (females)
Tail length: 15.6–24.7 cm / 6–10 in (males), 14.8–21.5 cm / 6–8 in (females)
Weight in winter: 500–1,580 g / 1–3 lb (males), 400–780 g / 1–2 lb (females)
Lifespan: Up to 10 years (wild), up to 11 years (captivity)
Range: North America, and introduced to parts of Eurasia and South America.
Conservation status: Least concern
Subfamily: Mustelinae
Recognised subspecies(25)

  1. Alaskan mink – (N. v. ingens)
  2. California lowland mink – (N. v. aestuarina)
  3. Common mink – (N. v. mink)
  4. Eastern or little black mink – (N. v. vison)
  5. Everglades mink – (N. v. evergladensis)
  6. Florida mink – (N. v. lutensis)
  7. Hudson Bay mink – (N. v. lacustris)
  8. Island mink – (N. v. nesolestes)
  9. Kenai mink – (N. v. melampeplus)
  10. Mississippi Valley mink – (N. v. letifera)
  11. Southern mink – (N. v. vulgivaga)
  12. Western or Pacific mink – (N. v. energumenos)
  13. N. v. aniakensis
  14. N. v. evagor
  15. N. v. lowii
References
  1. Davidson, A., Griffith, H. I., Brookes, R. C., Maran, T., MacDonald, D. W., Sidorovich, V. E., Kitchener, A. C., Irizar, I., Villate, I., Gonzales-Esteban, J., Cena, A., Moya, I. and Palazon Minano, S. 2000. Mitochondrial DNA and paleontological evidence for the origin of endangered European mink, Mustela lutreolaArchived 12 May 2020 at the Wayback Machine. Animal Conservation 3: 345–357.
  2. Marmi, Josep, Juan Francisco López‐Giráldez, and Xavier Domingo‐Roura. “Phylogeny, evolutionary history and taxonomy of the Mustelidae based on sequences of the cytochrome b gene and a complex repetitive flanking region.” Zoologica Scripta 33.6 (2004): 481-499.
  3. Abramov, A. V. A taxonomic review of the genus Mustela (Mammalia, Carnivora).” Zoosystematica rossica 8.2 (2000): 357.
  4. Harris, Stephen; Yalden, Derek (2008). Mammals of the British Isles (4th Revised ed.). Mammal Society. pp. 489–490.
  5. Seton, Ernest Thompson (1909). Life-histories of northern animals: an account of the mammals of Manitoba. New York: Scribner. pp. 879–880.
  6. Heptner, V. G.; Sludskii, A. A. (2002). Mammals of the Soviet Union. Vol. II, part 1b, Carnivores (Mustelidae and Procyonidae). Washington, D.C.: Smithsonian Institution Libraries and National Science Foundation.
  7. Kurta, A. 1995. “Mammals of the Great Lakes Region.” Ann Arbor, MI: The University of Michigan Press.
  8. Schlimme, K. 2003. “Neovison vison” (On-line), Animal Diversity Web. Accessed May 20, 2020.
  9. Feldhamer, George A., Bruce Carlyle Thompson, and Joseph A. Chapman. “Wild mammals of North America: biology, management, and conservation.” JHU Press, 2003. pp. 663–664.
  10. Harris, S., and D. W. Yalden. “Mammals of the British Isles, 4th edn (Southampton: Mammal Society).” (2008). p. 492.
  11. Ibarra, José Tomás, et al. “Invasive American mink Mustela vison in wetlands of the Cape Horn Biosphere Reserve, southern Chile: what are they eating?.” Oryx 43.1 (2009): 87-90.
  12. Macdonald DW; Harrington LA, 2003. “The American mink: the triumph and tragedy of adaptation out of context. New Zealand Journal of Zoology, 30(4):421-441. pp. 426.
  13. Baldwin, Marc. Wildlife Online. “Does surplus killing represent a waste of energy for foxes?” Accessed 19 July 2020.
  14. Olson, Kathryn M., and G. Thomas Goodnight. “Entanglements of consumption, cruelty, privacy, and fashion: The social controversy over fur.” Quarterly Journal of Speech 80.3 (1994): 249-276.
  15. Game & Wildlife Conservation Trust. Mink in Britain. Accessed February 21, 2021.
  16. Clode, D. A. N. I. E. L. L. E., and DAVID W. Macdonald. “Invasive predators and the conservation of island birds: the case of American mink Mustela vison and terns Sterna spp. in the Western Isles, Scotland.” Bird Study 49.2 (2002): 118-123.
  17. Maran, T. and Henttonen, H. 1995. “Why is the European mink, Mustela lutreola disappearing? – A review of the process and hypotheses.” Annales Fennici Zoologici 32: 47–54.
  18.  BBC Wildlife on One. (1992). “Invasion of the Killer Mink“.
  19. Jefferies, D. J., and H. M. Hanson. “The role of dieldrin in the decline of the otter (Lutra lutra) in Britain: the analytical data.” Journal of the International Otter Survival Fund 1 (2000): 95-143.
  20. BBC News. 11 June 2007. Otter numbers ‘continue to grow. Accessed 20 May 2020.
  21. Bachrach, Max (1953). “Fur: a practical treatise” (3rd ed.). New York: Prentice-Hall.
  22. Kidd, A. G., et al. Hybridization between escaped domestic and wild American mink (Neovison vison). Molecular Ecology 18.6 (2009): 1175-1186.
  23. Dunstone, Nigel. The mink. T. & AD Poyser, 1993.
  24. Bowman, J.; Kidd, A.; Gorman, R.; Schultehostedde, A. (2007). Assessing the potential for impacts by feral mink on wild mink in Canada. (PDF)Biological Conservation. 139 (1–2): 12–18. doi:10.1016/j.biocon.2007.05.020. Archived from the original (PDF) on 14 December 20202.
  25. Wilson, Don E. & Reeder, DeeAnn M. (Editors) 2005. Neovison vison in Mammal Species of the World. – A Taxonomic and Geographic Reference.

What Are Mustelids?

American Mink | Badgers | Ferret-Badgers | Fisher | Grisons | Martens | Otters | PolecatsTayra | Weasels | Wolverine