In a house, barn, or storage building, mice are a big problem. They eat and contaminate grains and other foods. House mice chew or shred anything that they can get their teeth on, including furniture, clothing, and electrical wires. Chewed electrical wires can sometimes start fires and cause electrical shorts in homes. Mice gnaw holes in walls, floors, and baseboards, and can even weaken wood structures. Like Norway rats, mice can also spread many diseases. Mice cost homeowners and farmers millions of dollars in damages every year.
 

The back of the deer mouse varies in color. Backs can be many shades of brown and some mice are pale gray. The underparts are usually white, including the underside of the tail, which tends to be as long as the body. It is a very small animal and weighs under 1 ounce. The total length of the body, including the tail ranges from 4 to 8 inches. The ears are quite large and are covered with fine hairs.
 

The deer mouse is found throughout North America. It likes dryland areas and is not found where the ground is continually wet. One study found that the female deer mouse was better at selecting home ranges with good food sources than the male mouse. Perhaps the female is more selective because she requires an excellent diet when raising her young. In order to produce the milk needed to feed the babies, the female must eat about three times the amount of food that she would normally require. Adults are usually solitary except during the mating periods. In winter, however, the animals sometimes share nests and sleep together for additional warmth.
 

The deer mouse is an omnivore, which means it eats both plants and animals. In the summer, their diet consists mostly of seeds and fruits but insects also are an important food source. Its favorite foods include rasberries, blackberries, blueberries, spiders, and beetles.
 

Mice are a source of food for many animals and therefore have many enemies. Only about five percent of the babies born live past the first year of life. Some enemies of the deer mouse are owls, weasels, foxes, snakes, skunks, minks, raccoons, bears, coyotes, and wolves.
 

It's difficult to say exactly how many litters the female deer mouse has each year. It varies from year to year and depends upon many things such as the weather and the local food supply. On average, the deer mouse has about four litters each year, but when conditions are very good, it may have up to 14 litters in a single year. Each litter normally consists of about four to six babies but a single litter may have as many as 12 or 13. In a very good year, a deer mouse that has 12 litters will produce 72 new offspring.
 

The male deer mouse plays an important role in the care of the babies. This is quite unusual because in many animal species the male plays no part in the raising of the young. Although the male is not present when the young are born, it does return to care for the babies. The male assists in the grooming of the young, helps with the nesting site, and teaches the young mice how to explore for food near the nest.