Critter Curriculum
mink photo
Mink Mustela vison The mink (Mustela vison) is a highly prized furbearer. It is a member of the weasel family, and is larger than both the long-tailed and short-tailed weasel. It is also one of the most aquatic members of the weasel family.

Physical Description The mink is approximately the size of a small house cat, with the male a tad larger than the female. It can grow to be 25 to 32 inches in length and may weigh from two to five pounds. Like all members of the weasel family, the mink has a long slender body and short legs. The five toes of each foot are partially webbed. Its small head is adorned with beady small eyes and short ears. The mink's coat is dark brown to black in color and has white patches on the chin, chest and belly. The fur also has long black oily guard hairs that stick out from under the soft undercoat. The mink is prized for its pelt and, in some areas, it is farmed for its pelt.

Life Cycle One female will likely find many suitors during the breeding season, which occurs from late February to early April. After mating, the fertilized egg remains in limbo through a process known as delayed implantation. During this period, all development of the embryo ceases for approximately seven to 30 days. After this time, the fertilized egg is implanted into the uterus wall and development of the embryo begins. A total gestation period of 51 days is average, but it can range from 40 to 75 days. The litter is born from April to May, and may vary in size from two to ten young, but is typically six or seven. The kits are born with eyes closed, little body hair and completely dependent on the female for survival. The young develop quickly; their first teeth emerge at 2 weeks, eyes open around four weeks, and they are soon weaned from their mother's milk. By seven weeks of age, the kits are roughly half of their adult size. They will stay with the mother through the summer and, in the fall, leave to establish their own territories. The females attain adult weight at four months and reach sexual maturity by 12 months of age. The males do not attain adult weight until nine to 11 months and reach sexual maturity by 18 months of age. Mink give birth and raise only one litter a year. Mink are extremely prolific and are able to replace their population entirely over a three-year time period.

Food Items The mink is an aggressive carnivore seeking out prey on land and in the water. It eats muskrats, rabbits, small rodents, waterfowl, marsh nesting birds, crayfish, aquatic beetles and fish. The mink swims well because of its partially webbed feet, which allow it to feed in and along rivers, streams, lakes and ponds. It is also a capable predator on land, quick and agile and an excellent tree climber. The mink's diet varies with the season, habitat and prey availability. In summer, much of its diet consists of small mammals, frogs, rodents, fish, and waterfowl. In winter, the mink relies more on mammals. The mink is a fierce predator that often attacks animals larger than it. Its underwater vision is poor so it will often locate the animal above the surface before diving in to retrieve it. On land, the mink relies on its sense of smell. The mink commonly stalks its prey by slinking along the ground. Being an opportunistic hunter, it will also frighten and then chase down its prey.

Habits & Habitat Though water is the determining factor when establishing territories, mink are more often found in coniferous and mixed forests than in deciduous forests. They can be found along streams, rivers, lakes and marshes. Any areas with a permanent water source are possible mink habitat. Wetlands that have abundant vegetation along the shoreline are also important, as well as those that have irregular shorelines, as they offer more cover and protection than if it were open and exposed. Mink live in burrows, which they may excavate themselves or use abandoned dens of another animal, such as muskrat dens or beaver lodges. These dens are commonly found along streams or pond banks. Mink often line the interior of their home with leaves and grass as well as fur from past prey. Mink are mainly nocturnal, mostly active at night, but can be seen any time of day. Mink are solitary creatures, except when rearing kits, and are considered to be more aggressive than sociable. It is not uncommon for male mink to fight, especially during mating season. Mink are territorial animals and mark ranges with a scent to warn other minks to stay away. They will challenge other mink and other species as well.

Abundance Mink are highly adaptable and tolerant of human activity. They are abundant in Vermont and well distributed. However, mink are susceptible to toxins in the water, such as mercury because they are at the top of the food chain. Maintaining clean water is important to mink survival and reproduction.

History The mink has always been a highly sought after pelt in the fur industry. Its sleek, luxurious coat is used to produce high quality clothing, which was in great demand in the early 1900s. In efforts to conserve the wild mink population, mink farms became popular and profitable in the mid 1950s. This greater supply of mink pelts provided consumers with mink clothing at a more affordable cost. From the 1950s to today, the value of the mink has fluctuated, reflecting our increasing and decreasing demands for fur.

Resource Utilization The mink is highly prized for its beautiful pelt, which has always been popular in the fur industry. With the high demand for this luxurious fur, mink are now raised on ranches, so as not to deplete their natural population. Although there has been a decline in demand in recent years, the number of mink pelts (wild and domestic) sold in 1999 was almost 3 million at a value of 72 million dollars.

Management Efforts The mink is a common species. In Vermont, its population is protected through highly regulated hunting and trapping seasons that occur in the fall. Another management tool is to protect their preferred habitat. The best habitat management practice for mink is to restore wetlands, and protect existing wetlands and buffer areas along streams and rivers.