American Mink

(Neovison vison)

Photo by Needsmoreritalin

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 supposed European mink is actually a semi-aquatic polecat; being much closer related to the European polecat and Siberian weasel.(1)(2) The American mink was once considered a weasel of the genus Mustela, but in 1999 the Latin name was changed to Neovison.(3)

Appearance

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 patches on the chin, chest, and throat. It’s smooth and thick in structure, with oily guard hairs that waterproof the mink’s coat. The summer coat is generally shorter, sparser and duller than the winter coat.

Winter coat: Longer, denser, silkier and much darker.

Habitat

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

Behaviour

American minks 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 minks use their enlarged anal glands to mark the boundaries of their territories.

American minks 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.(5)

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).(6) These burrows are characterized by numerous entrances and twisting passages, consisting of one to eight exits. They will occasionally line the interior of their den with dried grass and leaves, or fur from past prey.(7) American minks 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.(9)

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. They reach sexual maturity the following spring at about 10 months old.(9)

Diet

The diet of American minks 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.(10)

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)

Natural predators

Although adult American mink can generally defend themselves, their young can fall prey to bobcats, coyotes, wolves and birds of prey.(7)

Surplus killing

The American mink will occasionally exhibit surplus killing behaviour when presented with an abundance of food. However, most surplus food is 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. Similar to how we humans tend to hoard more food than we can eat during times of uncertainty, 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.

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. When it comes to mother’s milk “suckling” is a completely different reflex, and is something all mustelids stop doing once weaned. They also do not indulge in drinking blood.

Both of these myths are a construct of what some people have 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, it would serve the animal little dietary benefit, since consuming meat is far more important.

Colour mutations

Due to selective breeding, farm-bred American minks can range in colour from beiges, greys; to a brown that is almost black.(14) You’ll often see them portrayed as pure white in visual media, but this colour too is only created through selective breeding. The American mink’s natural colour in the wild is brown.

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.(15) Between the 1920s and 1950s, American minks were imported to Europe, the USSR and southern South America for fur-farming. Today in parts of Europe, released or escaped American minks have been classified as an invasive species and linked to the decline of the European mink,(16)(17) as well as other small mammals and birds. Similar to the importation of stoats in New Zealand, it was human greed and irresponsibility that led to this ecological disruption, not the imported mink.

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

Use in hunting (minkenry)

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

Range map

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: 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
Recognised subspecies(20)

  1. N. v. aestuarina
  2. N. v. aniakensis
  3. N. v. energumenos
  4. N. v. evagor
  5. N. v. evergladensis
  6. N. v. ingens
  7. N. v. lacustris
  8. N. v. letifera
  9. N. v. lowii
  10. N. v. lutensis
  11. N. v. melampeplus
  12. N. v. mink
  13. N. v. nesolestes
  14. N. v. vison
  15. N. v. vulgivaga

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.
  5. Seton, Ernest Thompson (1909). Life-histories of northern animals: an account of the mammals of Manitoba. New York: Scribner.
  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.
  10. Harris, S., and D. W. Yalden. “Mammals of the British Isles, 4th edn (Southampton: Mammal Society).” (2008).
  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.
  13. Does surplus killing represent a waste of energy for foxes? Wildlife Online. Accessed 19 July 2020.
  14. Bachrach, Max (1953). Fur: a practical treatise (3rd ed.). New York: Prentice-Hall.
  15.  Dutch minister reverses battery and mink ban. (Netherlands).(Defeat f…. 29 January 2009. Archived from the original on 09 May 2020.
  16. Clode D; MacDonald DW, 2002. 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, 49:118-123.
  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. 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.
  19. “Otter numbers ‘continue to grow” BBC News 11 June 2007. Accessed 20 May 2020.
  20. Wilson, Don E. & Reeder, DeeAnn M. (Editors) 2005. Neovison vison in Mammal Species of the World. – A Taxonomic and Geographic Reference.

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