American mink

The American mink (Neogale vison) is a semiaquatic carnivore native to North America. Semiaquatic animals are those that live both on land and in the water.

While they are native to North America, humans have introduced them to many parts of Europe, Asia, and South America. Because they have expanded into so many new areas, the IUCN classifies them as a least-concern species. This means they are not currently at risk of extinction. However, in their introduced range in Europe, they are often called an invasive species. This is because they can cause declines in local wildlife like the European mink, the Pyrenean desman, and the water vole.

An American mink's body is specialized for a life of hunting. They are carnivores, meaning they eat meat, including fish, crustaceans, frogs, birds, and rodents.

Their long, streamlined body helps them move through water with less resistance. This shape also allows them to enter the narrow burrows of their prey. Unlike stoats or weasels, which have slender, cylindrical tails, the mink has a larger, bushy, and tapering tail.

This tail can make up between 38% and 51% of its total body length. Their feet are broad and feature webbed digits to assist with swimming.

To help with diving, they undergo bradycardia, which is a process where the heart rate slows down to conserve oxygen.

The anatomy of a mink is quite distinct from its relatives. Their skull is more massive, narrower, and less elongated than that of the European mink. They possess larger and more massive upper molars to help them eat.

In the wild, their fur serves as a vital tool for survival. The winter fur is denser, longer, and softer than the summer fur. It is also more water-resistant due to thick underfur and oily guard hairs. This oily coating helps keep the animal dry while swimming. The fur colors range from dark blackish-tawny to light-tawny. Most minks have a white chin and lower lip.

There are 15 recognized subspecies of the American mink, each with unique traits and ranges.

For example, the Alaskan mink (N. v. ingens) is the largest subspecies. It is found in northern and central Alaska and the Yukon. In contrast, the Eastern or little black mink (N. v. vison) is the smallest. It lives in Eastern Canada and parts of the northern United States. Other subspecies have very different colors. The Atlantic salt marsh mink (N. v. lutensis) has a reddish-brown coat.

The Hudson Bay mink (N. v. lacustris) has dark chocolate-brown fur with white on its chin and breast.

Scientists have a long history of studying these animals. Fossil records show that American minks have existed since the Irvingtonian period. During the Pleistocene era, they were not very common among other animals.

While their size has remained somewhat similar to modern minks, there was a slight trend toward larger sizes from the Irvingtonian through the Wisconsinan periods. Taxonomically, the mink has also seen changes. It was once thought to be the only living member of the genus Neovison. However, researchers reclassified it and the extinct sea mink into the genus Neogale. This genus also includes several New World weasel species.

Behaviorally, American minks are very territorial. They maintain individual territories with very little overlap between members of the same sex.

However, there is often extensive overlap between males and females. They prefer undisturbed, rocky coastal habitats or areas with dense cover. Minks are also skilled climbers and can move on land with a bounding gait. They can reach speeds of up to 25 km/h. When they need to mark their territory, they use anal glands. These glands produce a very strong scent used for scent marking. Some observers have even described the smell as more intense than that of a skunk.

Finally, the American mink is a species of great economic importance. It is the animal most frequently farmed for its fur. In terms of economic value, it exceeds the silver fox, sable, marten, and skunk.

This farming has led to the development of various color mutations through experimental breeding. It is also important to note that domestic mink used on fur farms can differ from wild ones. Studies show that domestic mink can have brains that are 19.6% smaller, hearts that are 8.1% smaller, and spleens that are 28.2% smaller than those of wild mink. This shows how different environments and breeding can change a species' biology.