The common name is traced to the Swedish word manumitted The mink's close relation to the weasel is evident in its scientific name, Mustela vison which is the Latin word for weasel.
Description
Adults are almost entirely brown. The mink is one of few mammals in which males are decidedly larger than females. Males are 27 1/4 inches (692 mm) long while the largest female may be only 21 1/4 inches (539 mm) long; males weigh up to 3 pounds (1,474 g), females only 2 pounds (907 g).
A pair of musk glands in the anal region, typical of the Weasel Family, secretes a strong odor, considered by many to be more obnoxious than that of either weasel or skunk. This odor is given off particularly during the breeding season but also at any period of intense excitement.
Distribution and abundance
Minks are generally scarce in Missouri and are most common in the Mississippi Lowland where there is a systematic and extensive network of drainage canals and ditches.
Habitat and home
The basic requirement for mink habitat is permanent water. The presence of standing timber adjacent to water is attractive but not necessary for their environment. Minks dwell along the banks of streams and rivers or the shorelines of lakes and marshes. The increase in the number of farm ponds and lakes in Missouri has provided additional habitat. Minks make their homes under the roots of trees, in cavities in banks, under logs or stumps, in hollow trees or in muskrat burrows and lodges. The nest chamber, which may have several entrances, is about one foot (.3 m) in diameter and contains grass or leaves and sometimes fur or feathers.
Habits
Male minks travel widely. They have a large home range, up to five miles (8 km) in diameter, and take approximately two weeks to cover the entire area. Within this range is a series of temporary homes which are used in turn for a few days at a time. The territories of different males sometimes overlap, and several males may use the dens in succession. Female minks have a small home range which may not exceed 20 acres (8 ha), and they usually occupy only one or two homes throughout the year. Although tending to stay along streams and lakes, minks may cut across country from one body of water to another. One wide-ranging mink is recorded to have traveled 15 miles (24 km) in a night.
Minks are chiefly nocturnal, but they often come out at dawn or dusk and less frequently during the day. They are active all year, although during periods of low temperatures or following snow, they may stay in their dens and sleep for a day or so. Minks are not social and live alone except during the season when their young are being raised. They leave droppings and anal scent on flat stones or logs along watercourses.
Minks are well adapted to life both on land and in water. They usually walk or take low bounds 10-24 inches (254-609 mm) in length, arching their backs at each bound. They occasionally run at a speed of 7-8 miles (11.2-12.8 km) per hour. In order to obtain a better view of their surroundings, they often rear up on their hind legs. When disturbed, minks dodge into the nearest shelter and sometimes escape by climbing trees. They have been observed swimming under water for 50 feet (15 m) and swimming on the surface at the rate of l-l l/2 miles (1.6-2.4 km) per hour.
Minks are aggressive and often attack animals larger than themselves. They are good fighters and put up a good defense. Their eyesight is not acute, and they rely heavily on their sense of smell to locate prey. Most of their victims are killed by a bite in the neck. Their agility under water permits them to pursue and easily capture fish.
Foods
The mink preys upon mice, rabbits and other terrestrial animals as does the weasel, and like the otter, feeds on fish, crayfish and other aquatic forms. The principal winter foods of 372 minks in Missouri are given as percentages of the total volume: frogs 24.9; mice and rats 23.9; fish 19.9; rabbits 10.2; crayfish 9.3; birds 5.6; fox squirrels 2.2; and muskrats 1.3. Miscellaneous items (2.7 percent) include insects, spiders, snails, domestic cats, shrews, moles, bats, turtles and their eggs, snakes, birds' eggs, blood, grass and leaves.
Minks do not kill wantonly. Most food preferably is carried to a den where it is eaten. The surplus is cached in the den but frequently spoils and is not used.
Reproduction
The breeding season begins in late February, and matings occur until early April. Pregnancy varies from 40-75 days with an average of 51. This pattern of reproduction in the mink is similar to that in the long-tailed weasel since both species carry their young in a state of suspended development for some time.
The single annual litter of four or five young is born around the first of May. Males are only slightly larger than females at birth but become noticeably larger as they grow older. The eyes open when the kits are about 5 weeks old and weaning begins at this time.
Although a male may mate with many females, he usually stays with the last one and assists in caring for the young. When the kits are between 6 and 8 weeks of age, the adults take them on foraging trips for the first time. The family stays together until the end of August when all go their own way.
Importance
Mink fur is durable and of excellent texture. Small pelts are made into coats while larger ones are used for trimming. Rearing minks in captivity for fur production is practiced on a limited scale in Missouri.
In general,the mink's food habits are neither beneficial nor harmful to man's interests. At times, minks prey heavily on muskrats, but this occurs primarily when the muskrat population is overcrowded or suffering from drought. Minks occasionally take chickens, but as a rule they are not destructive.
Management
Regulation of the harvest must be continued in accordance with the mink population density. Log jams and brush piles along streams attract minks and should be left as part of the natural stream-course.
This series is abstracted from the revised edition of The Wild Mammals of Missouri by Charles and Elizabeth Schwartz. For more detailed information about this species and other mammals in Missouri, refer to this book. Your school library may have it or can borrow it for you from the inter-library loan service. This book can be purchased from the University of Missouri Press, P.O. Box 1644, Columbia, MO 65211, or the Missouri Department of Conservation, P.O. Box 180, Jefferson City, MO 65102.>
Missouri Mammals
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© 1981 Missouri Conservation Commission
