Varieties of Mice in Colorado

Colorado is home of 24 species of mice that fall into one of five varieties. Some mice can become pests, but the majority of species play a necessary role in the ecosystem of Colorado. Mice play a major part in the food chain, converting the energy from plant biomass and passing it on to the various predators that feed on mice.

Two species of harvest mice inhabit Colorado, the western harvest mouse and the plains harvest mouse. Both species are small small, brownish mice and difficult to distinguish. The plains harvest mouse is about 5 inches long, while the western harvest mouse is slightly longer and heavier. Harvest mice live on the eastern plains, and in the valleys of western Colorado. Harvest mice eat mostly grass seeds but also may consume insects. Active year-round, harvest mice reproduce during the warmer months with typical litters of three to five young.

The meadow-jumping mouse and the western jumping mouse comprise the two species of jumping mice in Colorado. These yellowish brown mice have white bellies with buff stripes on their sides and reach about 10 inches in length. The western jumping mouse inhabits the mountains; while the meadow jumping mouse live at the edge of the Great Plains. Jumping mice mostly feed on grass seeds and the occasional insect. Jumping mice hibernate in winter and begin storing fat in late summer. Jumping mice have a single litter of four to eight young in the summer after an 18 day gestation.

Five species of pocket mice call Colorado home; the olive-backed pocket mouse, the plains pocket mouse, the hispid pocket mouse, the silky pocket mouse and the Great Basin pocket mouse. The silky pocket mouse is the smallest species at about 4 inches long; the largest is the hispid, twice the length of the silky and 10 times heavier. Active throughout the year, pocket mice subsist mostly on grass seeds. Pocket mice breed throughout the warmer months, have a gestation period of about four weeks and produce litters of two to nine.

Meadow mice or voles have barely visible, short ears and blunt snouts. Colorado provides a home to eight species of voles. Except for the gray-colored, sagebrush vole and the southern red-backed vole, which has a brick-red patch on its back, voles have brownish coloring. Voles range in size from 6 to 7 inches in length depending on species. Most of Colorado supports one or more vole species. Voles mostly consume plants, though the heather and red-backed vole eat seeds, fruit, fungi, and some leaves. Females produce several litters of one to seven young per year.

The brush mouse, canyon mouse, deer mouse, pinyon mouse, rock mouse and the plain white-footed mouse make up the six species of white-footed mice that call Colorado home. White-footed mice vary in size from 6 to 8 inches long depending on species, all of which remain active year-round. White-footed mice can become pests in back-country cabins, though typically less of a nuisance than average house mice. White-footed mice inhabit all of Colorado. All species eat insects, seeds, fruits, flowers, leaves, and small carrion. They have several litters of five or more young, during the years' warmer months after a three-week gestation period.