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The House Mouse

Above photo: House mouse, Mus musculus, from Purdue Extension publication AS-692-W

The most common rodent pest in structures is the house mouse, Mus musculus. House mice exist in all 50 states of the U.S. When seen, some people scream, others climb on furniture, and others simply make a trip to town for some mouse traps or poison.

According to the Internet Center for Wildlife Damage Management (ICWDM), house mice are small, slender rodents with a slightly pointed nose; small, black, somewhat protruding eyes; large, sparely haired ears; and a nearly hairless tail. House mice are gray-brown with a gray or buff-colored belly. Adult house mice have a body length (nose to base of tail) of 3 to 4 inches. They typically weigh 0.4 to 0.9 ounces.

I think most people recognize a house mouse when they see it. However, similar species include other mice species and shrews. Rats resemble mice, but they are larger rodents.

ICWDM indicates that litters of 5 or 6 young are born 19 to 21 days after mating, although females that conceive while nursing may have a slightly longer gestation period. Mice may breed year-round, but when living outdoors they mostly breed in spring and fall. A female may have 5 to 10 litters annually.

House mice live in and around homes, farms, commercial establishments, and open fields.

ICWDM indicated that mice eat many types of food but prefer seeds and grain. They sample new foods and are considered “nibblers.” Foods that are high in fat, protein, or sugar (e.g., bacon, chocolate, butter, nuts) may be preferred, even when grain and seeds are present. An individual mouse consumes about 1/10 of its body weight each day and up to 8 pounds per year. Mice contaminate far more food than they consume through their urine and feces. 

They said that mice cause damage to structures through gnawing and nest-building. In livestock confinement facilities and similar structures, they quickly can cause extensive damage to insulation inside walls and attics. Such damage also occurs in homes, apartments, and commercial buildings.

ICWDM said that mice often damage large electrical appliances by chewing wiring and insulation, resulting in short circuits, fire hazards, and other costly malfunctions.

They said that in homes and commercial buildings, mice may feed on stored food items and pet foods. They contaminate food with their urine, droppings, and hair. On farms, they damage structures that store feed and equipment. Mice often act as reservoirs or vectors of diseases, such as swine dysentery, leptospirosis, and salmonellosis.

ICWDM said that mice and their parasites transmit salmonellosis (food poisoning), rickettsial pox, and lymphocytic choriomeningitis to humans. Mice also may carry leptospirosis, rat bite fever, tapeworms, and the organisms that cause ringworm, a fungal skin disease of humans. Urine of mice may be an asthmatic trigger in some people. 

They covered several preventive and control methods people can employ. Proper sanitation around structures is helpful. This reduces sources of food, water and shelter. Rodent-proof construction is recommended, along with proper storage and disposal of refuse and garbage. They indicated that ultrasonic frightening devices are generally not effective. Repellants and toxicants are options to consider. Trapping devices, such as snap traps, cage and box traps, and glueboards may also be considered for use.

ICWDM provides research-based wildlife damage information. For more information, visit their website at

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