Least Weasel

Least Weasel

weasel
The Flickr photo was taken by Keven Law.

The Least Weasel (Mustela nivalis) is small mammal generally larger than a mouse yet smaller than a rat. It has an elongated slender body (5-7 inches) with a short tail (1-2 inches) and short limbs. In the summer, the Least Weasel has short dense brown fur with a light underbelly and white feet and black eyes. In the winter months, it molts into its camouflage white color with a few black hairs on the tip of its tail. Its dark eyes, smaller round ears, and long whiskers are easy to see. Teeth are small and sharp, with prominent canines. The feet have five fingers with sharp claws. Weasels are not rodents but are closely related to skunks and minks. 


The Least Weasel inhabits open areas such as meadows, marshes, brushy areas, and agricultural fields. Weasels are mostly nocturnal. It easily slips through the burrows of mice and other small rodents, killing its prey quickly with a bite to the back of the skull. Pound for pound one of the toughest predators around, the Least Weasel is a fierce predator and possibly Nebraska's smallest carnivore. Food habit studies revealed that they eat mice primarily, and sometimes consume 50% of their weight in mice nightly. Small birds, eggs, small snakes, and shrews are fair game when the opportunity presents itself.
Least Weasels mark their territory with a pungent musk that they also use to warn predators. They elicit a high-pitched sound when challenged.

A Least Weasel can enter domestic poultry, fowl, or avian confinements and readily take eggs, and kill chicks and smaller adult species. Proper exclusion is the best solution. These weasels can dig, climb, and slip through any entries greater than ½ inch. Use strong secure wire as they can rip thin wire and many materials. You are allowed to trap weasel in Nebraska but first must obtain a permit from Nebraska Game & Parks Commission. No toxicants or poison baits are registered for use on weasels in Nebraska.

Image of Dennis Ferraro
Dennis Ferraro
Professor of Practice - Conservation Biologist/Herpetologist and Community Engagement Coordinator

Dennis Ferraro is the resident herpetologist and an professor of practice at the University of Nebraska - Lincoln School of Natural Resources. He has been a UNL faculty member since 1990.

Dennis is located at:
415 Hardin Hall
3310 Holdrege Street
Lincoln NE
68583-0974
402-472-8248