Like house mice, deer mice in the Peromyscus genus are smaller (2-3″ with 2-3″ tail) than rats. They can be distinguished from house mice by their large eyes and light-colored bellies. Deer mice commonly infest vacant structures or seldom-used outbuildings, but may occasionally be found in occupied homes, especially in rural areas.
Deer mice are the primary vector for hantavirus in western North America. Approximately 10% of deer mice in San Mateo County are infected with hantavirus, a potentially deadly viral respiratory infection.
If you suspect deer mice have been inside your home or another structure, please follow safe cleanup guidelines.