This one's feisty, you guys.
The American Mink (Neovison vison) is a scrappy little semi-aquatic carnivore whose home range is in North America, but has been classified as an invasive species after it was introduced to Europe. Because they are semi-aquatic, they prefer to make their dens in hollow logs or tree stumps, among the roots of trees, or dug into a riverbank close to the water. They are known by several indigenous names: doke-sesch (Yankton Dakota people), tel-chu-say' (Denesuline), atjackasheiv or sang-gwiss or shakzuashew (Cree), lo-chin'-cha (Oglala Lakota), and shang-gwes'-se (Ojibwe).
The body type of the American Mink is closer to that of the American Marten than it is to stoats and weasels. They are streamlined and muscular, with webbed digits, which makes them strong swimmers while reducing water resistance. American Mink are also farmed for their fur, more than any other animal. Farmed American Mink have smaller brains and internal organs than wild American Mink, but are larger in overall body size. Adult males can grow up to 18 inches (45 cm) in body length - not including the tail - and weigh about 3 pounds (1.58 kg). Females are slightly shorter at 15 inches (37.5 cm) and lighter at 2 pounds (0.78 kg).
When describing the diet of the American Mink, it might take up less space to talk about what this animal doesn't eat. Just click through to this gallery of pictures and look at the things that this little guy will try. They will eat amphibians, birds, rodents, fish and crustaceans. It attacks vertebrate prey items by chomping down on the back of its head or neck, and it's not unusual to see them take down prey that is as big or bigger than they are. This voracity is what has made it an invasive species in Europe - its appetite threatens water voles, European mink, and the Pyrenean desman.
Mating season for the American Mink occurs in spring, starting in February for mink in the southern part of its range, and in April for mink in the norther part of its range. It can be a violent season for both males and females, as males will fight each other for access to females and become violent during the act of mating itself. Pregnant females delay implantation to time the births to happen during the summer, with actual gestation lasting about 30 days. There are one to four kits in a litter, and they will stay with their mother until autumn.
It's not uncommon for farmed American Mink to escape their cages, which can have a negative impact on the wild population. They are territorial creatures, and when there are too many of them in one territory they will fight it out. The larger size of the farmed American Mink gives it an advantage in this way, but if it survives to successfully reproduce it can introduce weaker genes into the pool. Though the U.S. Fur Commission claims that American Mink are "fully domesticated," referring to the length of time they have been farmed by humans, they do not make good house pets.
Source for all images used in this post.