Short-tailed Weasel (Ermine)

Short-tailed weasels are mammals in Yellowstone National Park

NPS

 

Short-tailed weasel track

Scientific Name

Mustela erminea

Identification

• 8–13 inches long, 2.1–7 ounces.
• Typical weasel shape: very long body, short legs, pointed face, long tail.
• Males about 40% larger than females.
• Fur is light brown above and white below in summer; all white in winter except for tail, which is black-tipped all year.
• Compare to long-tailed weasel and marten.

Habitat

• Eat voles, shrews, deer mice, rabbits, rats, chipmunks, grasshoppers, and frogs.
• Found in willows and spruce forests.

Behavior

• Breed in early to mid-summer; 1 litter of 6–7 young per year.
• Can leap repeatedly three times their length.
• Will often move through and hunt in rodent burrows.