Appearance.

Mink are mammals with long, slim bodies and short legs characteristic of mustelids, a family that also includes weasels, the river otter (Lontra canadensis), and the pine marten (Martes americana). Males and females usually have dark brown fur with white patches on the chin, chest, and throat areas. Most similar in size and color to pine martens, male mink are noticeably larger than females. Unlike weasels, mink fur color does not change to white during the winter.

Range and Habitat.

Mink occupy various habitats across North America, favoring streams, ponds, or lakes with nearby brushy or rocky cover. They are not found in the southwestern United States or far northern Canada. Mink occasionally occupy dens, which are often abandoned streambank muskrat burrows. Females with young offspring occupy dens more frequently. Other den sites include roots of trees, logjams, or abandoned beaver lodges.

Hunting and Food.

With eyes that are incompletely adapted to see underwater and with limited capacity to dive for more than a few seconds, mink are better suited for hunting along shorelines than in open water. Mammals such as muskrats, rabbits, and rodents are important year-round foods. In summer, mink supplement their diet with marsh-nesting songbirds and invertebrates such as crayfish and aquatic beetles. Fish become more common in the mink's winter diet.

Reproduction.

Minnesota mink begin breeding in late winter with the lengthening of winter daylight. Young are born in April or May, usually in litters of four to six kits. The young remain with the female until the end of summer. Larger young male mink leave their mother first when grown, followed by smaller males. Some young females delay dispersal until the following spring.

Behavior.

Mink have a reputation for ferociousness based on their aggression during mating and their habit of killing animals of equal or larger size. They tend to be solitary, keeping the boundaries of their home range separate from mink of the same sex. Female mink home ranges, however, are sometimes located within larger male mink home ranges.

Mortality.

Aside from disease and predation, trapping is likely the most significant cause of death. Mink are prey to coyotes, bobcats, snakes, raptors, and other mink.

Relationship to People.

Although mink populations are considered secure throughout their range, human activities that alter shallow-water ecosystems, such as stream channelization, wetland drainage, and dam construction, can damage or destroy mink habitat. Mink are trapped for their fur and are also bred for it. Mink ranching, not trapping, accounts for the majority of commercially marketed mink pelts.