There are three species of weasels in Minnesota, the short-tailed weasel, the long-tailed weasel, and the least weasel. All belong to a family of mostly long, narrow "tube-shaped" animals in the family Mustelidae.

Identification

General description: Weasels are small, elongated predators that are brown in the summer, but that turn white in the winter. During spring and fall, as they change color, weasel fur appears blotchy.

Length: The least weasel is the shortest species, measuring only about 7 inches. The long-tailed weasel is the longest at 16 inches, including the six inch tail.

Weight: The tiny least weasel weighs in at less than two ounces, while its long-tailed cousin weighs about seven ounces.

Color: All species of weasels are brown on top and white-yellow on their undersides in summer, and turn white in winter. The short-tailed weasel's tail has a black tip in winter.

Reproduction

Female least weasels breed in early spring, and five weeks later, give birth. Both the female short-tailed and long-tailed weasels exhibit "delayed implantation," whereby they are bred in summer, but the young do not begin to develop until spring. All weasel species have the same litter size, which averages four to six young.

Food

Ounce for ounce, weasels are fierce predators. They are excellent mousers, and are efficient at raiding mouse nests. Other foods are new-born rabbits, insects, small birds, and carrion.

Predators

For their small size, weasels can defend themselves very well, and their brown-in-summer and white-in-winter camouflage helps them to both kill prey, and avoid being prey. The weasel's main predators are other species of weasels, small hawks and owls, and its bigger cousin, the mink.

Habitat and range

All three species can be found state-wide, but the least weasel is the least abundant, especially in northeastern Minnesota. Weasels can be found anywhere that their main prey, mice, are found. Typical habitats are grasslands, woodlots, and brush piles. Weasels can also be found in firewood piles and garages, where they also hunt mice.

Population and management

Weasels are unprotected in Minnesota, and only a few thousand are trapped for their fur in winter. The short-tailed weasel is also called "ermine" and is best known for its fur used for trim on coats.

Fun facts

The fur of the least weasel fluoresces (glows) in ultraviolet light. Weasels have voracious appetites, and the least weasel eats about 30 percent of its weight each day. Because weasels have a high surface area to weight ratio, they conserve body heat in winter by curling into a ball and lowering their metabolism.