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Deer mouse identification: how to recognize the main hantavirus reservoir
Visual and behavioral cues to distinguish the deer mouse (Peromyscus maniculatus) from house mice and other rodents.
The deer mouse (Peromyscus maniculatus) is the primary reservoir of Sin Nombre virus in North America. Distinguishing it from the much more common house mouse (Mus musculus) matters because deer mice carry hantavirus, while house mice do not in the same way.
Visual cues:
- Body color: deer mice have a sharp two-tone coat — brown or grey on top, pure white on the belly and under the tail. House mice are uniformly grey-brown all over.
- Tail: deer mouse tails are bicolored (dark above, white below) and roughly the same length as the body. House mouse tails are uniformly dusky and look "naked".
- Eyes and ears: deer mice have larger black eyes and bigger, more prominent ears relative to body size.
- Size: 7-10 cm body length plus tail. House mice are slightly smaller and stockier.
Where you find them:
- Deer mice are wild rodents — they prefer rural areas, woodlands, fields, sheds, cabins, and outbuildings rather than active human dwellings.
- House mice live with humans year-round in cities and towns.
- Finding deer mice indoors usually means a cabin, garage, or storage space that has been closed for a while.
Other hantavirus reservoirs you should know:
- Cotton rat (Sigmodon hispidus): southeastern USA, carries Black Creek Canal virus.
- Rice rat (Oryzomys palustris): southern USA, carries Bayou virus.
- Long-tailed pygmy rice rat (Oligoryzomys longicaudatus): South America, carries Andes virus.
- Striped field mouse (Apodemus agrarius): Asia and Eastern Europe, carries Hantaan virus.
- Bank vole (Myodes glareolus): Northern Europe, carries Puumala virus.
If you find rodents matching the deer mouse profile in a building, do not sweep or vacuum dry. Follow the wet-cleaning protocol with disinfectant, gloves, and a fitted mask. Report sustained infestations to the property owner or local health department.