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Smithsonian National Museum of Natural History, North American Mammals

  Carnivora · Mustelidae · Mustela frenata

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Mustela frenata

Long-tailed Weasel

Order: Carnivora
Family: Mustelidae

Image of Mustela frenata
Mustela frenata - winter coat, left; summer coat, center; "Bridled Weasel", right
Click to enlarge. (65 kb)

Conservation Status: Least Concern.

Long-tailed Weasels are voracious predators, foraging day and night for small vertebrates, and scavenging for carrion when necessary. In captivity, adults can consume an amount equal to one-third their own body weight in 24 hours. In the wild they may store food in a burrow or near a kill site. They are solitary except for the July-August breeding season. Both males and females maintain territories, marking them with chemical secretions from anal glands. Litters usually comprise 4-5 pups, born in a den. In 12 weeks they reach full adult body weight and begin hunting for food, pursuing mates, and establishing territories. Foxes, raptors, Coyotes, domestic dogs and cats, and rattlesnakes all prey on Long-tailed Weasels, and although they can live in a variety of habitats, population densities are low. In some locations they are endangered, and in others, considered threatened or species of concern.

Also known as:

Bridled Weasel

Sexual Dimorphism:

Males are larger than females.


Range: 330-420 mm males; 280-350 mm females


Range: 160-450 g males; 80-250 g females


Lichtenstein, M.H.C., 1831.  Darstellung neuer oder wenig bekannter Saugethiere, pl. 42 and corresponding text.


Mammal Species of the World (opens in a new window).

Mammalian Species, American Society of Mammalogists' species account * (opens in a new window).
* PDF reader available here (opens in a new window).

Distribution of Mustela frenata

Image of Mustela frenata
Click to enlarge. (119kb)

Image of Mustela frenata
Click to enlarge. (64kb)

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