The house mouse (Mus musculus) is one of the most frequently encountered rodent pests found near people and buildings. It quickly can establish itself in your home. This mouse is believed to be the second most populous mammalian species on Earth, after Homo sapiens. Mice nest in any undisturbed location, often in wall cavities, behind cabinets, in attics and garages. Their nests are made of shredded fibrous material such as cloth or paper. The house mouse usually weighs no more than one ounce. Its body is 2-3½" long with a tail measuring 3-4". Mice are primarily nocturnal, meaning they are active and feed mostly during the night. They get the water they need from the food they eat but will drink water when they find it. They'll eat many foods, but prefer seeds and cereal grains. On average, a mouse ventures only 10-30 feet from its nest. Mice can jump over 12" high, climb up the sides of buildings, and cross cables and wires. They also swim.

Mice have litters of 3-14 young. The unborn mice develop in 19-21 days. One female can have 5-10 litters per year. The newborn are blind and furless. Females reach sexual maturity at about 6 weeks and males at about 8 weeks, but both can breed as early as 35 days. House mice usually live under a year in the wild.