The house mouse is a smooth, silky, gray- to brown-colored rodent (color varies from dark to light) with a lighter belly and a nearly hairless tail. Adult head and body length is 2 1/2 to 3 1/2 inches and the tail are 2 1/2 to 4 inches long. Droppings are 1/8 to 1/4 inch long and tapered at the ends. The eyes are small and the ears are large enough to fold over the eyes. Evidence of a mouse infestation includes fecal droppings and urine stains, an acrid smell, gnaw marks and holes, runways and tracks in the dust, burrows, damaged goods, and sometimes noise.

The reproductive cycle of the house mouse is fast, as mice reach sexual maturity within 35 days. They will mate at the age of 6 to 10 weeks and. once pregnant, give birth about 19 days later. The newborn mice are hairless and blind. In 3 to 4 weeks, young mice are weaned and begin to forage on their own but remain in the nest with their mother. A new litter of 5 to 8 mice can be produced every 40 to 50 days when conditions are good (food and nesting areas are available). Mice will quickly infest a building if they have what they need. Under natural conditions, mice are thought to live about one year, but they can live much longer in captivity. An individual mouse needs only 1/10 ounce of food and 1/20 ounce of water per day to survive. This factor illustrates why sanitation is critical to mouse control.

The house mouse is the number one rodent pest and the most commonly encountered rodent in buildings. House mice gnaw on just about anything. They cause fires by chewing on wires or gathering nesting materials in junction boxes or around electric hardware. Mice damage structures by gnawing holes in wood and wall board. They damage all types of goods and feed on and contaminate stored food, especially cereals, nuts, and seeds. As they move along, mice and other rodents constantly release urine and fecal droppings. A mouse can produce up to 50 droppings a day. They spread disease-causing organisms such as Salmonella in their urine and feces. Many people suffer with respiratory allergies triggered by mouse dander (particles shed from the fur) and the droppings they leave behind. Parasites of mice that affect humans include fleas and tropical rat mites, both of which can become problems when mice die in buildings.