The mice that we’ve been trapping lately in our garage look different. They’re more brown in color with a white belly. These aren’t baby rats, are they!? A. Y., Paxton, MA

No, they’re not baby rats. I suspect that you have been trapping deer mice, the country cousins of house mice. Deer mice (Peromyscus maniculatus) are so closely related to white-footed mice (Peromyscus leucopus), that the term deer mice is often used for both species.

No Longer Strictly an Outdoor Mouse

The deer mouse is the most widely distributed outdoor mammal in North America. Deer mice used to be considered mostly rural, outside mice while house mice were the mice we found indoors. Those boundaries seem to have blurred lately since deer mice are commonly found today trying to move indoors (see Are Deer Mice More Common Than House Mice?).

Deer mice are a tawny brown compared to the overall gray of house mice. Deer mice also have a white belly and white legs and feet. Most people that have an opinion about mice agree that deer mice are cuter than house mice with their large eyes and ears (see What Does a Deer Mouse Look Like?). The two mice are similar in size.

The habits of deer mice are similar to those of house mice. They will construct nests of shredded paper, insulation, furniture stuffing, or whatever they can find. Deer mice are known for hoarding food in out-of-the-way places, saving for a rainy day. Unfortunately, this stored food often becomes infested by food beetles and moths which creates a new pest problem.

Deer Mice Have a Connection With Lyme Disease

In our Northeast region, both the white-footed mice and deer mice are known for their role in the transmission of Lyme disease. Both act as reservoirs for the disease when they are bitten by the blacklegged tick (=deer tick) that transmits Lyme disease (see Deer Mice Are Cute, But Could Be Bad For Your Health!). This doesn’t mean that having deer mice in your home is going to subject you to Lyme disease, you have to be bitten by an infected tick for that to happen. Deer mice are only part of the equation. But a high incidence of deer mice on your property, if combined with other conditions, could mean that you are at higher risk for Lyme disease transmission.

Deer mice are also directly connected with the transmission of hantavirus. This disease is spread when people inhale airborne dust particles that are contaminated with mouse urine, droppings, or saliva. Hantavirus is rare in the U.S., occurring mostly in a few western states.

If you’re having a problem with deer mice, you should contact a professional exterminator. At Colonial, we’re very familiar with the control of deer mice and we are also experts at rodent-proofing – sealing up all those little openings that mice use to get inside. Give us a call.
Photo credit: Friends of Seney National Wildlife Refuge / Foter / CC BY-SA