Learn About the Dangers of Deer Mice

As cute as it appears to be, the gray to brown and white deer mouse (Peromyscus maniculatus) is a potentially dangerous creature since it can spread disease.

The deer mouse is about 5 inches long, with:

• Big eyes
• Ears that are prominent and leaf-like, but generally shorter than a hindfoot
• Head and body of about 2 to 3 inches long
• Tail at about the same; another 2 to 3 inches long.

This rodent gets its name from the fact that it resembles a deer: its upper body is gray to reddish-brown, its underbelly and legs are white, and its tail is bicolored—dark on top and white on the sides and bottom.

The deer mouse is omnivorous, eating just about anything, and nocturnal, being most active at twilight. Unlike other mice, it is not a very good climber. Although this mouse prefers woodlands and rural areas, it will also make its home in urban areas. In fact, it will live about anywhere it finds concealed shelter with food nearby, such as in underground burrows, brush piles, and weedy/grassy areas; under logs, stumps, or rocks; in abandoned dens of other animals and cavities of trees.

The Dangers of the Deer Mouse

Found throughout North America, this cute-looking rodent carries and spreads Lyme disease and is the primary carrier of hantavirus in the U.S.

• Lyme disease: Deer mice also transmit Lyme disease. This disease is carried by a bacteria that is transmitted by the deer tick between mammal hosts, such as deer mice, rabbits, white-tailed deer, and, yes, humans.
• ​Hantavirus: The disease is transmitted primarily through the inhaling of contaminated air, but also through contact with the urine, feces, or saliva of infected mice. Because there is still no recognized cure, it is important to avoid contact with deer mice and areas they are known to frequent or where infestations are or have been present.

Hantavirus strains can also be transmitted by other mice, including:

The White-Footed Mouse (Peromyscus leucopus)

• This mouse closely resembles the deer mouse, but can be differentiated by the deer mouse's two-colored tail; hairier, shorter tail; whitish tufts of hair that often appear at the base of ears, and usually longer hair or fur.
• Together, its head and body lengths are about 4 inches and its tail about 2 to 4 inches.
• Similar to the deer mouse, the fur on top of its body is darker—pale to reddish-brown—while its underbelly and feet are white.
• It is found in many areas of the U.S., including the east coast from the south up through southern New England, the Midwest and the west, as well as Mexico.
• Like the deer mouse, it prefers concealed harborage, but it will also live in open areas.

The Cotton Rat (Sigmodon hispidus)

• With its head and body that measure 5 to 7 inches in length and its tail adding another 3 to 4 inches, this rodent is much larger than the deer mouse.
• In coloring, it is grayish-brown to black, and its fur is long and coarse.
• In the U.S., this rat is found primarily in the southeast states and it prefers to live in areas that are overgrown with weeds, shrubs, or tall grass.

The Rice Rat (Oryzomys palustris)

• Smaller than the cotton rat, the rice rat is larger than the deer mouse. It can also be differentiated by its very long tail: with a head and body measuring 5 to 6 inches, this rat can be 4 to 7 inches long.
• Its coloring is more like the bi-colored deer mouse, with grayish-brown fur on top and gray or tawny coloring beneath. Its fur is short and soft.
• As its name would indicate, this semi-aquatic rat prefers areas such as those of rice paddies that are wet and marshy.
• In the U.S., it is found primarily in the southeast.

Because other rodents may also present dangers, it is wise to avoid close contact with rodents in general.