House Mouse

Physical Characteristics

The adult house mouse ranges from 2 1/2 to 3 3/4 inches in combined length of head and body, with a tail length of an additional 2 3/4 inches. Its fur is short and its color is gray, with either light gray- or cream-colored fur under its belly.

house mouse

Mice are found where food and shelter are plentiful, and if you’re seeing mice active in the daytime, you’ve most likely got an exploding mouse population. Their typical lifespan is less than one year, but some live as long as six years. One pair of mice can lead to a population explosion; in a year, they can pump out eight litters, with five to eight pups per litter. Mice prefer nesting sites that are dark, in secluded places with an abundance of nesting materials, which can include paper products, cotton, packing materials, insulation and fabrics. Mice typically will eat anything, but they prefer seeds and insects. When feeding on high-protein food, mice require water, but they prefer sweetened liquids. House mice are territorial, and will show aggression to unrelated males and females outside of their social structure. During daily territory patrols, a mouse will investigate and explore to see if anything is new or different, and it will establish new travel routes if necessary. Territories vary in size, but they typically are relatively small. Mice may gain access through openings larger than 1/4 inch, which allow them many points of entry. Their runways, or paths, tend to be along walls and objects on the floor, and those paths are free of dust or cobwebs, but contain droppings, which are 1/8 to 1/4 long, rod-like and smooth, with pointed ends (if the droppings are grooved with blunted ends, they probably came from an American cockroach). Mice can be vectors, and may carry or contribute to the following diseases: hantavirus pulmonary syndrome, salmonellosis, lymphocytic choriomeningitis, leptospirosis (aka Weil’s disease), rat-bite fever (aka streptobacillary fever, spirilarry fever), ringworm, dermatitis, bubonic plague, murine typhus and rickettsial pox.


Good sanitation practices are essential for effective long-term control – as with other pests, eliminating sources for food and water help to keep mouse populations from exploding. A mouse can enter any opening larger than 1/4 inch, so exclusion measures, such as screening, caulking or otherwise closing off access points, also can help keep mice out. Mouse traps can help control the population, but use baits like peanut butter rather than cheese, and set traps abutting and perpendicular to walls, as mice tend to follow paths along walls. As for rodenticides, some mice will ingest the poison and then escape inside a wall or other hidden place before they die, so odor can become a real problem. If you have an exploding mouse problem, the rodent experts at Clark Pest Control can determine the best means of control for your individual situation.

Latin name: Mus musculus, et al.