Mice as Pests:Identification, Risks, and Behavior

Mice are small rodents of the order Rodentia distinguished by their pointed snouts, small rounded ears, body-length scaly tails, and relatively high breeding rate. There are several species of mouse, though the most common mouse pests in North America are the house mouse (Mus musculus), the white-footed mouse (Peromyscus leucopus), and the deer mouse (Peromyscus maniculatus).

These three mouse species vary only slightly in appearance. All are between 5 and 8 inches long (including tail), with the house mouse being the smallest. House mice are gray-brown with almost completely-hairless tails. Deer mice are greyish- or reddish-brown with white-colored feet and undersides and shorter, hairier tails. White-footed mice looking virtually identical to deer mice, except they are slightly larger.

Mice are considered problematic pests for two reasons: disease and structural damage. Mice are prolific chewers and can gnaw through almost anything, from papers and plastics to rubber-coated cords and wood support beams. A large-scale mice infestation can cause severe property damage over time. Worse, individual mice can harbor a host of diseases — including Hantavirus, Salmonella, and Lymphocytic Choriomeningitis (LCMV) — that they can transmit directly to humans. Mice can also carry ticks and fleas, which can transmit the following diseases: Lyme Disease, Colorado Tick Fever, Babesiosis, and Rickettsialpox.

Causes of Mice Infestations

Mice infest human properties in search of food and shelter. As the weather gets colder, mice will gravitate towards indoor spaces to keep warm. They can enter buildings through small holes in roofs, walls, and foundations, or sneak in through open doors and windows. When inside, mice will feed on small crumbs and other food scraps left out in the kitchen or other rooms. They will also raid open trash cans and chew through easily-accessible paper and plastic to find food and shelter. To stop mice from entering your space, block all openings into your property, no matter how small. If you already have mice in your space, remove all easily accessible food sources to make traps more effective.