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Least Weasel Mustela nivalis


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Least Weasel
credit: Kevin Law/CCSA

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Family: Mustelidae, Weasels view all from this family

Description North America’s smallest carnivore; lacks a black tail tip. In summer, back varies from rusty brown to pale sandy tan; belly is white or yellowish. Northern populations have a pure white winter coat. Molting animals may appear spotted.

Dimensions 180-205mm, 25-40mm, 40-55g; / 165-180mm, 22-30mm, 30-50g

Habitat Alpine & subalpine habitats, Grasslands & prairies, Swamps, marshes & bogs, Beaches, shorelines & estuaries, Meadows & fields

Range Plains, Great Lakes, Mid-Atlantic, Rocky Mountains, Southeast, Eastern Canada, Western Canada, Alaska

Discussion Rarely seen, even though active day and night year-round. Well-developed senses of sight, smell, and hearing allow them to use postural, vocal, and olfactory communication. Preys on mice day and night; must eat its body weight in food each day. Slender body plan allows them to chase mice down burrows. Prefers marshes, grasslands, and other nonforested areas.