Colorado is home to six species of white-footed mice – the deer mouse, brush mouse, pinyon mouse, canyon mouse, rock mouse and just plain white-footed mouse. These animals differ in size (from six to eight inches long), relative length of tail, and length of ear. All are active throughout the year. Deer mice have been implicated as a major carrier of Hantavirus, a serious, acute lung disease. Only knowledgeable people, properly equipped, should work in closed areas where mouse droppings and urine are concentrated. Understanding of Hantavirus is changing rapidly; the Colorado Department of Health and Environment
is an excellent source of current information.
Deer mice (which occur at higher elevations than the other kinds) are quite active beneath the mountain snow-pack, but they also become dormant for hours and days at a time. White-footed mice often are abundant, and they are important food for predators, including snakes, owls, foxes, weasels, badgers and bobcats. They sometimes become pests in backcountry cabins, but generally are less of a nuisance than the introduced house mice.
Range: Only the wettest habitats in the state are without one or more species. The deer mouse lives statewide. The other five species are more restricted to smaller parts of the state. Common names hint at habitats of four of the species: brush mice live in oak-brush, pinyon mice in juniper-pinyon woodland, canyon mice in slick-rock canyons on the Western Slope, rock mice in the rocky foothills of the Eastern Slope. The white-footed mouse proper occurs in woodlands along the Arkansas River and its tributaries and the deer mouse lives just about everywhere that is not under water, paved or previously occupied by a bigger species of Peromyscus.
Diet: All eat seeds, fruits, flowers, leaves, a little carrion and a lot of insects.
Reproduction: All species produce several litters of five or more blind, hairless young after a gestation period of about three weeks throughout the warmer months of the year.
By David M. Armstrong
Department of Ecology & Evolutionary Biology
Environmental Studies Program, University Museum of Natural History
University of Colorado-Bouldermausmann@aol.com