Mustela vison
Order: Carnivora
Family: Mustelidae
Status: This valuable furbearer is one of the most widespread
carnivores in North America. Official Montana furbearer managed and
protected by regulated fur harvest seasons.
Identifying Characteristics: This medium-sized, semi-aquatic carnivore
has a long, thin body; short, sturdy legs; short, pointed nose; short, rounded
ears, and a dorsoventrally flattened head. Thickly furred tail.
Usually rich dark brown in color with a white chin patch. Sometimes white
spots on belly. Fur is soft and lustrous with long, glossy guard
hairs. Dense pelage is its only obvious aquatic adaptation. Total
length: 19 to 28 inches. Weight: 1.5 to 2 pounds.
Habitat: Usually found along streams and lakes. Commonly occurs
in marshes and beaver ponds. Permanence of water and dependable source of
food are most important habitat components. Often uses den sites of other
animals and is commonly found in association with muskrats.
Food Habits: Preys primarily on small mammals, birds, eggs, frogs, and
fish. Its diet is almost entirely animal. During summer preys on
waterfowl.
Life History: Semi-aquatic forager. Can kill prey larger than
itself. Chiefly nocturnal, territorial, and secretive. Dens
underneath piles of brush or driftwood, under rocks, in hollow logs, and in
houses or dens abandoned by beavers or muskrats. Very aggressive mating
behavior. Mates from January through March; 40 to 79 day gestation;
delayed implantation; young born during April or May; averages 4 to 5 per
litter.
Similar Species: Weasel - has white or yellow underparts. Marten
- has buffy patch on throat and breast. River otter - much larger.
Further Information
