A common gray or brownish-gray mouse (Mus musculus) that lives in or near buildings and often carries disease. It is frequently used in laboratory experiments. Common mouse species (Mus musculus, family Muridae), the mouse most often encountered in buildings. The house mouse has been distributed by humans from Eurasia to all inhabited areas of the world and usually seeks shelter and food in human dwellings. Brown or gray, it grows up to 8 in. (20 cm) long, including a 4-in. (10-cm) tail. It consumes almost anything edible, even sampling soap, paste, and glue. It matures quickly and is ready to mate two to three months after birth. In warm areas or heated buildings, it breeds throughout the year