Menacing Mice

Source(s): Jim Howell, Ph.D., Entomologist, The University of Georgia

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House mice are one of the most troublesome and economically important pests in the United States. They consume food meant for human beings, pets and other animals; contaminate areas with their feces and urine; cause considerable damage to structures and property; and spread numerous diseases.

Identification

The house mouse (Mus musculus) is a small, slender, grayish-to-brown rodent having large ears, small black eyes and a slightly pointed nose. A house mouse weighs 1/2 to 4/5 ounce and is approximately 5 to 7 inches long, including the 3- to 4-inch tail. A house mouse lives about one year and reaches sexual maturity in 6 weeks.

Biology

House mice are found in and around homes and commercial structures as well as in open fields and agricultural lands. They came to the United States with the early Colonists and rapidly spread across the entire country.

They are generalist feeders but prefer seeds and grain. They also love foods high in fats, sugar and proteins, like bacon, chocolate candies and butter.

Mice are nibblers and though they may eat only about 3 grams of food a day, they destroy much more food than they consume. A single female may have up to five to ten litters a year, each litter having about five to six young. With that in mind, a single fertilized female can result in a large indoor population in a relatively short period of time.

Nests consist of fibrous material like cloth, rags or paper, usually in the form of a ball about 4 to 6 inches in diameter.

Mice are found in virtually any sheltered location. Indoors, they may be in a hole in the woodwork, or beneath some protective cover. Outside, they may nest in animal burrows, in collected plant material or beneath debris. When mice are present in significant numbers, their infestation is announced by a characteristic musty odor.

They are nocturnal and aren’t often seen by the homeowner, but their droppings, black pellets about 1/8 to 1/4 inch long and tapering on both ends, is a sure indication of their presence.

Damage

The house mouse is considered one of the most irksome and economically important pests in the United States. It gnaws on electrical wiring and may cause fires or failure to appliances; it pollutes clothes, food, furniture and other items with its droppings and urine; and it can spread disease when its waste products contaminate our food.

Control

The homeowner has a few options, including traps, rodenticides (poisons), and calling a licensed pest control company.

When populations are small, traps are the preferred method. They are less of a hazard for pets and children. and the mice can be removed promptly without the accompanying odor of animals dying in wall spaces and other inaccessible places. Snap traps are readily available at most grocery and hardware stores. Baiting with bacon or peanut butter gives excellent results.

Rodenticides should be used as a last resort because of hazards to children and pets. Extreme care should be taken to position these products in areas inaccessible to other animals and children.

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Center Publication Number: 243