As cute as it appears to be, the deer mouse (Peromyscus spp.) can be a very deadly creature. This innocent-looking little rodent is the primary spreader of hantavirus, which causes very serious disease.
Called a deer mouse because it somewhat resembles a very small deer, this mouse's upper body is grey to reddish-brown, its underbelly and legs are white, and its tail has two colors: dark on top and white on the sides and bottom. With big eyes and prominent, leaf-like ears, the deer mouse is a deceptively cute creature.
Getting rid of an infestation of deer mice, and denying them entry to your home, is a serious matter considering the consequences. Here's what you should do to control the rodent.
3 Ways to Get Rid of Deer Mice
Many of the same control measures used for common house mice will also work for deer mice, but care must be taken to avoid physical contact with the mice. Since deer mice are typically outdoor dwellers that seek indoor shelter only when cold weather approaches, prevention and control measures often focus on outdoor areas and on blocking entry points into the home.
Encourage Natural Predators
A variety of wild predators can help control deer mice populations around your home. Deer mice prefer outdoor locations, so they are especially susceptible to predators.
Owls and other raptor species of birds are prodigious hunters of mice and other small rodents, as are a variety of snakes and hunting mammals, such as foxes and coyotes. If you live in an area where such hunting creatures exist, they shouldn't be feared, but rather encouraged.
Deer mice can be caught with the same types of traps used to catch ordinary house mice. If using kill traps, take care not to touch the mice with your bare hands; you may want to use a protective breathing mask and wear gloves when disposing of mice, and when cleaning up nests or droppings.
Outdoor trapping is possible and live traps are an option for those who live in areas where other wild creatures such as chipmunks and squirrels could be inadvertently caught. It's important to note that live trapping increases the risk of disease exposure and transmission. If one does use this method the utmost caution must be taken when handling the live mouse and the trap.
Use Rodent Baits/Poisons
The same rodenticides used for house mice and rats will also kill deer mice dwelling in your home. But make sure to use these chemicals in a manner that protects humans and pets from accidental ingestion. And never use rodenticides outdoors, where dogs and desirable wildlife can reach them. Make sure to follow label directions when using rodenticides.
What Causes Deer Mice?
Like many other rodents, deer mice seek areas where there are sources of food and water and shelter from the elements. Unlike house mice, which prefer indoor dwelling year-round, deer mice are more typically outdoor feeders living on plant seeds and fruits that seek indoor shelter only when the weather turns cold.
How to Prevent Deer Mice
There are a variety of measures you can take to make your home less likely to experience deer mice:
- Seal holes and gaps in your home or garage. Deer mice very often seek indoor shelter when the weather turns cold, so inspecting and sealing gaps should be part of each year's winterizing routine.
- Clean up and/or put away exposed food to make it less attractive and less accessible to rodents (and other pests). Deer mice are especially fond of seeds, fruits, and other dried foods, so make sure to store birdseed and pet foods in sealed, impenetrable containers.
- Maintain mouse traps in and around your home to monitor rodent presence. This will help you identify if you have a deer mouse problem.
- Clean up litter and piles where rodents like to live and breed.
- Keep the areas near your home free of brush piles, tall grass, and other dense foliage where deer mice often live.
Deer Mice vs. Other Potentially Harmful Rodents
Although it is the primary carrier, the deer mouse is not the only carrier of hantavirus. Other prime carries include:
- White-footed mouse (Peromyscus leucopus): Closely resembling and closely related to the deer mouse, the white-footed mouse is found in many areas of the U.S., including the eastern coast from the South up through southern New England, the Midwest, and the West, as well as Mexico. These rodents are nearly identical to deer mice, but they have distinctive white feet.
- Cotton rat (Sigmodon spp.).: With a head and body that measures 8 to 14 inches from the tip of the nose to the end of the tail, this rodent is much larger than the deer mouse. In the U.S., this rat is found as far north as Nebraska in the west and coastal and central Virginia to the east. It prefers to live in areas that are overgrown with weeds, shrubs, or tall grass.
- Rice rat (Oryzomyini spp.): Though smaller than the cotton rat, the rice rat is still larger than the deer mouse. As its name hints, this semi-aquatic rat prefers wet and marshy areas like rice paddies. In the U.S., it is found primarily in the Southeast.
How does a deer mouse differ from a house mouse?
There are two predominant species of deer mice, both of which can spread hantavirus. They are nearly identical in appearance, distinguished only by the territory they occupy. The eastern deer mouse (Peromyscus maniculatus) is widespread through territory east of the Mississippi, except for lowland areas of the Southeast. The western deer mouse (Peromyscus sonoriensis) is found throughout forests and grasslands of the western U.S., including the desert regions of the Southwest. These two species were once lumped together as P. maniculatus, but are now considered separate. The deer mouse is slightly larger than the common house mouse, around 6 to 8 inches from the tip of the nose to the end of the tail, vs. the 5- to 7-inch overall length of the house mouse. And deer mice have a notable white underbelly that extends to the underside of the tail. This white belly is not found on the house mouse, which is entirely brown or gray. Deer mice are primarily outdoor feeders that may seek indoor shelter during cold weather, while the house mouse is more likely to be a permanent indoor dweller.
Where are deer mice most likely to be found?
Although the deer mouse prefers woodlands and rural areas, it will also make its home in urban areas and cities. It may live about anywhere it finds concealed nesting areas and nearby food, such as in underground burrows, brush piles, and weedy or grassy areas; under logs, stumps, or rocks; in abandoned dens of other animals, and the natural cavities of trees. Though preferring outdoor living, this rodent does seek indoor shelter when the weather turns cold.
For reasons not fully understood, most cases of hantavirus respiratory disease occur in western states, usually at higher altitudes. There have, however, been occasional cases as far east as New York, as well as in the Midwest.
Rodents in the United States That Carry Hantavirus. Centers for Disease Control and Prevention.
Hantavirus Pulmonary Syndrome. British Columbia Centre for Disease Control.
Trap Up! Centers for Disease Control and Prevention.
Deer Mouse Management. Agricultural and Natural Resources, University of California.
Hantavirus remains rare but potentially deadly. Yale School of Public Health.
Hantavirus Ecology. Centers for Disease Control and Prevention.