The house mouse is the smallest member of the subfamily in Oregon and smaller that most other members of the family. The ears are large and membranous; the tail is long, tapering, and scaly; and the soles of the feet are naked. The pelage is short, harsh, and usually grayish brown to nearly black dorsally, lighter brown or buffy ventrally. Albino, spotted, and other colormorphs are known to occur.

House mice occur throughout the world in association with humans. In Oregon, this mouse is found in 30 of the 36 counties. House mice are usually more active at night, but within barns, warehouses, and other buildings with subdued light, they may be active at any time. Even when active, these mice usually spend most of their time behind or beneath some object and dash between the items that provide cover.

Photo by J. N. Stuart, Flickr