Deer Mice and Other Disease-Carrying Mice

They Can Be Deadly

Deer Mouse (Peromyscus maniculatus)
The Cute but Deadly Deer Mouse. Kitchin and Hurst/All Canada Photos/Getty Images

As cute as it appears to be, the gray to brown and white deer mouse (Peromyscus maniculatus) is actually a very deadly creature.

The deer mouse is about 5 to 8 inches long with

  • Big eyes
  • Ears that are prominent and leaf-like, but generally shorter than a hind foot
  • 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.

Deadly Disease-Carrying Mice

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 DiseaseDeer 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. First recognized in 1993, more than 130 people have been diagnosed with Hantavirus Pulmonary Syndrome (HPS) since then. Half of those affected died from the disease. 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 (4) usually longer hair or fur.
  • Together, its head and body length is about 4 inches, and its tail about 2 - 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 measures 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 carry viruses or diseases, it is wise to avoid close contact with rodents in general.

Rat and Mouse Control

Some standard rodent control methods will work against these rodents as well, but the best defense against virus-transmitting rodents is a good defense as detailed in 10 Common Pest Control Terms.