Gray, brown, or black coat; lighter underparts; short hair; oval ears; long tail. Females have five pairs of nipples, while males have none. Because mice have a similar biology to humans, they are used in laboratories to study diseases and test drugs.
Mainly nocturnal. Territorial. Agile climber and swimmer. Often stands on hind legs while foraging.
Mainly on seeds and plants.
Occurs in all habitats, including deserts. Common in urban areas in proximity to humans.