Description: The mink can be distinguished by: 1) long, slender body, 2) short legs, 3) toes equipped with nonretractile claws, 4) soft and lustrous fur, the underfur thick and gray-brown in color, while the long, shiny guard hairs range in color from chocolate brown to nearly black, 5) undersides only slightly lighter than the dorsal surface, often with white blazes on the chin, throat, cheeks, and chest, and 6) moderately long, well-furred, bushy tail, the same color as the body at the base, but shading to black towards the tip. Males are larger than females.
Size: Adults may attain the following dimensions: total length 491-686 mm; tail 154-241 mm; hind foot 57-76 mm; ear 22-27 mm; weigh 616-1137 grams.
Range and Habitat: The mink is found throughout Kansas, but is less common in the western third of the state. Mink prefer habitat along stream and river banks, lake shores, forest edges near water, and swamps. Brushy areas appear to be particularly favored. Individuals are rarely found far from water.
Reproduction: Breeding begins in late January and may continue through mid-March. Males will mate with any available female in estrous. Following fertilization the eggs cease development for eight to 45 (average 21) days. Development resumes 30 to 32 days before birth; gestation may cover 40 to 75 (average 51) days. Three to six (usually three or four) blind young are born in late April or early May. The kits are naked or slightly furred. Their deciduous teeth erupt between 16 and 49 days of age, and their eyes open at 25 days, at which time they are covered with short reddish-gray fur. At this time the female begins to bring solid food to the young. They are weaned between five and six weeks. By eight weeks of age the young accompany the female while she hunts. They disperse in late August. The male may help the female raise the offspring, but this has not been verified.
Young females reach adult size at about four months, and are sexually mature at 10 to 12 months. Males are full grown at nine to eleven months, and are sexually mature at 18 months.
Habits: Mink are primarily nocturnal and crepuscular, although they are also active during the day, especially in overcast weather. Home ranges vary due to sex, time of year and habitat. During winter, home ranges appear to be restricted unless food availability is extremely low, in which case the mink may abandon an area. Female home ranges usually cover six to 15 hectares. Males occupy an area of 18 to 24 hectares in rime habitat, but may cover five square kilometers during breeding seasons. Movements of up to 29 kilometers have been reported when food abundance is low, but often cover only 4.8 to 6.4 kilometers. Population densities vary from less than one to eight or nine animals per square kilometer. Unlike other members of the genus, the mink is well-adapted to the water and spends considerable time searching for aquatic prey.
Dens are usually located under tree roots on river banks, and in tree holes or hollow logs. Occasionally mink construct their own dens, but also frequently use abandoned bank burrows of beavers and muskrats. Typically, the mink den consists of a burrow 2.5 to 3.6 meters long and 100 mm or more in diameter. The burrow is usually 0.6 to 0.9 meters below ground and has one or more above-water entrances. The nest area is 0.3 meters in diameter and frequently lined with grass, leaves, and fur. Males females maintain separate dens and are essentially solitary.
Food: The mink's diet is subject to seasonal and local variations. However, they are highly carnivorous, rarely eating any vegetable material. Mammals appear to constitute the majority of the diet, especially voles, ground and tree squirrels, rabbits, and deer mice. Other food items include muskrats, fish, crayfish, mollusks, grasshoppers, worms, birds, frogs and snakes.
Remarks: Mink are not abundant in the western portion of the state, and with lowering water tables will probably become less common there due to habitat alteration. They are major predators of small and medium-sized mammals, and rarely prey on either sport fish or game birds. Predators of the mink appear to be great horned owls, bobcats, bears, red foxes, coyotes, and wolves. The mink is thought to live a maximum of four to six years in the wild, and up to sixteen years in captivity.
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