Russian mink, Eurasian mink
The European minks (Mustela lutreola) are small carnivores once widely distributed over almost the whole of the European continent and currently surviving in a few enclaves as fragmented populations. The huge change in its numbers and distribution means it is one of the most endangered mammals in Europe and the world.
The European mink has a greatly elongated body with short limbs. It has a large, broad head with short ears. The limbs have relatively well-developed membranes between the digits, particularly on the hind feet. 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 that 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.
The current range of the European mink 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). In Estonia, the European mink population has been successfully re-established on the island of Hiiumaa, and there are plans for repeating the process on the nearby island of Saaremaa. European minks inhabit riparian areas where they are found on banks of rivers and streams. They rarely occur far from fresh water.
European minks are solitary wanderers, with home ranges of river. Summer territories are smaller than winter territories. Along shorelines, the length of a home range varies from 250-2,000 m (270-2,190 yd), with a width of 50-60 m (55-66 yd). They rarely use the same burrow, the female usually staying close to the den, except when a food shortage drives her to find another site. An individual will use a permanent burrow as well as temporary shelters, the permanent one used all year round except during floods, being 6-10 m (6.6–10.9 yd) from the edge of the water. European minks are somewhat sedentary and stay in their burrows for long periods during very cold weather. Around dusk and before sunrise are their most active times. They are fast and agile animals, which swim and dive skilfully. They are able to run along stream beds, and stay underwater for one to two minutes. When swimming, they paddle with both their front and back limbs simultaneously.
European minks are carnivores and opportunistic predators. They mainly eat rabbits, rates, birds, fish, crayfish and frogs. They may also eat insects and vegetation.
Little is known about the mating system of European minks, however, as they lead a solitary life and meet only to mate, it may suggest the animals exhibit a polygynous mating system. The mating season is from February to March. Gestation is about 35-72 days, and births occur in April and May. A litter numbers between two and seven, and usually is about four or five. The young can open their eyes at 4 weeks and their teeth appear within 15-17 days, being replaced with adult teeth at 60-72 days. Weaning takes place at about 10 weeks, when they begin tracking and catching prey. At 56-70 days they go with their mother on hunting expeditions, and become independent at 70-84 days. European minks reach reproductive maturity at about 1 year of age.
Populations of this species have suffered a series of commercial and ecological threats. In parts of Europe, serious threats facing this sensitive species are habitat loss and degradation, due to the significant increase during the past decades of water pollution and hydroelectric developments. Another major threat is commercial trapping for the animal’s fur. Accidental deaths due to pest control trapping and poisoning occur, as well as vehicle collisions, particularly frequent in the west of this species’ range. Furthermore, all mink species are susceptible to Aleutian disease, which causes persistent infection, is highly contagious and often is lethal.
According to the Animal Diversity Web (ADW) (University of Michigan) resource, the world total populations size of the European mink is less than 30,000 individuals. This includes approximately 25,000 European minks in Russia, approximately 2,000 minks found in France and approximately 1,000 minks in northern Spain. According to the IUCN Red List, the Russian population of European mink has been estimated at about 20,000 individuals; Spain holds near 500 individuals; in Romania - 1,000-1,500 individuals; Estonia - fewer than 100 individuals on Hiiumaa Island. Overall, currently European minks are classified as Critically Endangered (CR) on the IUCN Red List and their numbers today are decreasing.