The European mink (Mustela lutreola), also known as the Russian mink and Eurasian mink, is a semiaquatic species of mustelid native to Europe.
It is similar in colour to the American mink, but is slightly smaller and has a less specialized skull. Despite having a similar name, build and behaviour, the European mink is not closely related to the American mink, being much closer to the European polecat and Siberian weasel (kolonok). The European mink occurs primarily by forest streams unlikely to freeze in winter. It primarily feeds on voles, frogs, fish, crustaceans and insects.
The European mink is listed by the IUCN as Critically Endangered due to an ongoing reduction in numbers, having been calculated as declining more than 50% over the past three generations and expected to decline at a rate exceeding 80% over the next three generations. European mink numbers began to shrink during the 19th century, with the species rapidly becoming extinct in some parts of Central Europe. During the 20th century, mink numbers declined all throughout their range, the reasons for which having been hypothesised to be due to a combination of factors, including climate change, competition with (as well as diseases spread by) the introduced American mink, habitat destruction, declines in crayfish numbers and hybridisation with the European polecat. In Central Europe and Finland, the decline preceded the introduction of the American mink, having likely been due to the destruction of river ecosystems, while in Estonia, the decline seems to coincide with the spread of the American mink.
Evolution and taxonomy Fossil finds of the European mink are very rare, thus indicating the species is either a relative newcomer to Europe, probably having originated in North America, or a recent speciation caused by hybridization. It likely first arose in the Middle Pleistocene, with several fossils in Europe dated to the Late Pleistocene being found in caves and some suggesting early exploitation by humans. Genetic analyses indicate, rather than being closely related to the American mink, the European mink's closest relative is the European polecat (perhaps due to past hybridization) and the Siberian weasel, being intermediate in form between true polecats and other members of the genus. The closeness between the mink and polecat is emphasized by the fact the species can hybridize.
Subspecies , seven subspecies are recognised.
SubspeciesTrinomial authorityDescriptionRangeSynonymsNorthern minkM. l. lutreola (Nominate subspecies)Linnaeus, 1758The pelt is dark brownish-chestnut or dark brown with a diffuse broad belt on the back. The tail tip is black and the underfur is dark bluish-grey. The overall pelage is long, compact and silky. Adult males measure in body length and have a tail length of (38% of its body length).Northern European Russia and Finlandalba (de Sélys Longchamps, 1839) alpinus (Ogérien, 1863) europeae (Homeyer, 1879) fulva (Kerr, 1792) minor (Erxleben, 1777) wyborgensis (Barrett-Hamilton, 1904)French minkM. l. biedermanniMatschie, 1912Francearmorica (Matschie, 1912)M. l. binominataEllerman and Morrison-Scott, 1951caucasica (Novikov, 1939)Middle European minkM. l. cylipenaMatschie, 1912A very large subspecies, it is only slightly smaller than M. l. turovi. The fur is quite dark and corresponds to the colour of M. l. novikovi. Adult males measure in length, while females measure . Tail length in males is , while in females it is .The Kaliningrad Oblast, Lithuania, western Latvia, middle Europe (except the extreme west (France), Hungary, Romania, the former Yugoslavia and Poland)albica (Matschie, 1912) budina (Matschie, 1912) glogeri (Matschie, 1912) varina (Matschie, 1912)Middle Russian minkM. l. novikoviEllerman and Morrison-Scott, 1951A moderately-sized subspecies, it is slightly larger than M. l. lutreola. It is lighter-coloured than M. l. lutreola, being dark tawny or dark brown with a film of light reddish highlights. The dark belt on the back is weakly defined or absent. The pelage is overall shorter, less dense and less silky than M. l. lutreola. Adult males measure in body length.The middle zone of the European part of the former Soviet Union (Estonia, eastern Latvia, Belarus, eastern Ukraine, and the lower Don and lower Volga regions)borealis (Novikov, 1939)Carpathian minkMustela l. transsylvanicaÉhik, 1932Smaller than M. l. turovi, with dark tawny furMoldavia, Romania, Hungary, Bulgaria and the former Yugoslaviaehiki (Kretzoi, 1942) hungarica (Éhik, 1932)Caucasian minkM. l. turoviKuznetsov in Novikov, 1939A large-sized subspecies, it has quite long, but sparse and coarse pelage and less compact underfur. The fur is light tawny or light brown with clear rusty highlights. The underfur is light bluish-grey. White chest markings are much more frequent in this subspecies than in others. The ends of the limbs are often white. Adult males usually measure more than long.The Caucasus, the lower Don and lower Volga regions, probably eastern Ukraine
Description Build
The European mink is a typical representative of the genus Mustela, having a greatly elongated body with short limbs. However, compared to its close relative, the Siberian weasel, the mink is more compact and less thinly built, thus approaching ferrets and European polecats in build. The European mink has a large, broad head with short ears. The limbs are short, with relatively well-developed membranes between the digits, particularly on the hind feet. The mink's tail is short, and does not exceed half the animal's body length (constituting about 40% of its length). The European mink's skull is less elongated than the kolonok's, with more widely spaced zygomatic arches and has a less massive facial region. In general characteristics, the skull is intermediate in shape between that of the Siberian weasel and the European polecat. Overall, the skull is less specialized for carnivory than that of polecats and the American mink. Males measure in body length, while females measure . Tail length is in males and . Overall weight is . It is a fast and agile animal, which swims and dives skilfully. It is able to run along stream beds, and stay underwater for one to two minutes. When swimming, it paddles with both its front and back limbs simultaneously.
Fur
The winter fur of the European mink is very thick and dense, but not long, and quite loosely fitting. The underfur is particularly dense compared with that of more land-based members of the genus Mustela. The guard hairs are quite coarse and lustrous, with very wide contour hairs which are flat in the middle, as is typical in aquatic mammals. The length of the hairs on the back and belly differ little, a further adaptation to the European mink's semiaquatic way of life. The summer fur is somewhat shorter, coarser and less dense than the winter fur, though the differences are much less than in purely terrestrial mustelids.
In dark coloured individuals, the fur is dark brown or almost blackish-brown, while light individuals are reddish brown. Fur colour is evenly distributed over the whole body, though in a few cases, the belly is a bit lighter than the upper parts. In particularly dark individuals, a dark, broad dorsal belt is present. The limbs and tail are slightly darker than the trunk. The face has no colour pattern, though its upper and lower lips and chin are pure white. White markings may also occur on the lower surface of the neck and chest. Occasionally, colour mutations such as albinos and white spots throughout the pelage occur. The summer fur is somewhat lighter, and dirty in tone, with more reddish highlights.
Differences from American mink The European mink is similar to the American mink, but with several important differences. The tail is longer in the American species, almost reaching half its body length. The winter fur of the American mink is denser, longer and more closely fitting than that of the European mink. Unlike the European mink, which has white patches on both upper and lower lips, the American mink almost never has white marks on the upper lip. The European mink's skull is much less specialised than the American species' in the direction of carnivory, bearing more infantile features, such as a weaker dentition and less strongly developed projections. The European mink is reportedly less efficient than the American species underwater.
Behaviour
Territorial and denning behaviours
The European mink does not form large territories, possibly due to the abundance of food on the banks of small water bodies. The size of each territory varies according to the availability of food; in areas with water meadows with little food, the home range is , though it is more usual for territories to be . Summer territories are smaller than winter territories. Along shorelines, the length of a home range varies from , with a width of .
The European mink has both a permanent burrow and temporary shelters. The former is used all year except during floods, and is located no more than from the water's edge. The construction of the burrow is not complex, often consisting of one or two passages in diameter and in length, leading to a nest chamber measuring . Nesting chambers are lined with straw, moss, mouse wool and bird feathers. It is more sedentary than the American mink, and will confine itself for long periods in its burrow in very cold weather.
Reproduction and development During the mating season, the sexual organs of the female enlarge greatly and become pinkish-lilac in colour, which is in contrast with the female American mink, whose organs do not change. In the Moscow Zoo, estrus was observed on 22–26 April, with copulation lasting from 15 minutes to an hour. The average litter consists of three to seven kits. At birth, kits weigh about , and grow rapidly, trebling their weight 10 days after birth. They are born blind; the eyes open after 30–31 days. The lactation period lasts 2.0 to 2.5 months, though the kits eat solid food after 20–25 days. They accompany the mother on hunting expeditions at the age of 56–70 days, and become independent at the age 70–84 days.
Diet The European mink has a diverse diet consisting largely of aquatic and riparian fauna. Differences between its diet and that of the American mink are small. Voles are the most important food source, closely followed by crustaceans, frogs and water insects. Fish are an important food source in floodlands, with cases being known of European minks catching fish weighing . The European mink's daily food requirement is . In times of food abundance, it caches its food.
Range and status The European mink is mostly restricted to Europe. Its range was widespread in the 19th century, with a distribution extending from northern Spain in the west to the river Ob (just east of the Urals) in the east, and from the Archangelsk region in the north to the northern Caucasus in the south. Over the last 150 years, though, it has severely declined by more than 90% and been extirpated or greatly reduced over most of its former range. The current range includes an isolated population in northern Spain and western France, which is widely disjunct from the main range in Eastern Europe (Latvia, Estonia, Belarus, Ukraine, central regions of European Russia, the Danube Delta in Romania and northwestern Bulgaria). It occurs from sea level to . In Estonia, the European mink population has been successfully re-established on the island of Hiiumaa, and a project to re-establish them on the nearby island of Saaremaa is underway, with the first minks arriving in 2022.
Decline