From: Saunders, D. A. 1988. Adirondack Mammals. State University of New York, College of Environmental Science and Forestry. 216pp.
Description: The mink has short legs; a long, muscular body and neck; and a short flattened head. The ears are short and rounded. The eyes are small, beady and black. The five, clawed toes of each foot are partially webbed. The furred tail accounts for about one-third of the total length, and is slightly busy. Long, glossy guard hairs overlay the dense underfur. The fur is a dark, chocolate brown except for the white chin, small white patches that may be present on the underparts of the body and the black-tipped tail. An adult is approximately 46-68 cm (18.1-26.8 in) in total length, and weighs 0.5-1.4 kg (1.1-3.0 lb). Females are smaller than males.
Range and Habitat: The range is Alaska, most of Canada and the U.S. except for parts of the arid southwest. Minks are common residents of the water courses of the Adirondack Park, especially lakes, rivers, and the larger streams. Minks dig burrows or use those of other mammals such as muskrats. Burrows, which are always near water, consist of tunnels 0.3-0.9 m (1-3 ft) below the surface of the ground, 10-15 cm (4-6 in) in diameter, and up to 3.7 m (12 ft) in length. Burrows often contain a nest chamber 15 cm (12 in) in diameter lined with dry vegetation and the fur and feathers of prey. Each burrow usually has several entrances. A mink may use up to 20 different burrows during its life. Minks also den in hollow logs and stumps, muskrat huts and rock piles.
Food and Feeding Behavior: The carnivorous mink hunts a variety of aquatic and terrestrial prey. Frogs, fish, crayfish, mice, voles, muskrats, shrew, moles, freshwater mussels, turtles, snakes, birds and their eggs, and even insects are some of the animals that occur in the diet. Fish, crayfish, frogs, and small mammals are major food items. Minks rely on their keen sense of smell to locate prey on land, and hunt and kill prey in a manner similar to other weasels. Minks frequently carry or drag prey to their dens before consuming it. They may cache excess food in the den or some other nearby location.
Activity and Movement: Minks travel on land and in the water. They walk, run, and bound on land, and may attain speed of 13 km/hr (8 mph) for brief periods. Minks may occasionally climb trees, but are not normally arboreal. This semiaquatic species swims on the surface and underwater, covering as much as 15 m (50 ft) or more when submerged. Individuals range widely during the breeding season and periods of food scarcity. A mink may remain in its den for several days after a severe winter storms, but otherwise is active throughout the year. Much activity occurs at twilight and at night, but it is not unusual for a mink to forage during the day in winter and while caring for young.
Reproduction: Mating takes place in late winter or early spring. The gestation period is variable but averages 51 days (range 40-75). Most embryonic development occurs during the last 28-32 days of pregnancy. Females bear their annual litter in April or May. Litter size varies from 2-10, but averages 4 or 5. Newborn minks weigh 8-10 g (0.3-0.4 oz). They are blind at birth and either naked, or have white, fine-textured fur on their backs. The eyes open at 21-35 days, and weaning commences at 35-42 days. When they are 56 days old, the young begin to capture prey while accompanying the female on her hunting trips. The young disperse in August-September, and are sexually mature at 10 months of age. Potential longevity is 16 years, but most wild minks survive only 3-6 years.
Predators: As is typical of most mustelids, the mink has few predators other than humans who harvest this valuable furbearer. Bobcats, foxes, coyotes, fishers, and great-horned owls occasionally kill minks.
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Hamilton, W.J., Jr. 1940. The summer foods of minks and raccoons on the Montezuma Marsh, New York. Journal of Wildlife Management, 4:80-84.
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