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Types of mice in Western U.S.

There are many different species of mice in the United States. The four most common mouse species found in the Western United States are the following:

If you see any type of mouse in your home or business, there is a good chance there are more to be found. Give us a call or send us a message to have one of our specialists come out to survey the property.


Deer mouse

Deer mouse (or field mouse)

(Peromyscus maniculatus)

Deer mice are common along the west coast from Mexico to the Northwest territories of Canada. They may also be referred to as field mice.

What they look like

  • Length: 4-9 inches, including the tail
  • Weight: 0.38-1.25 oz.
  • Long bi-colored tails, covered in very short hair
  • Fur can be pale gray to deep red on the head and back and white on the belly
  • Hind feet have six pads each


  • Gestation period is 21-24 days
  • Three to five mice per litter
  • Two to four litters per year
  • Lifespan of 2-24 months due to high predation


  • Nocturnal creatures - come out at night to find food
  • Excellent climbers
  • Seek shelter inside during colder months
  • A primary carrier of the hantavirus, which leads to Hantavirus Pulmonary Syndrome in humans
  • Commonly found near structures that border wooded areas
House mouse

House mouse

(Mus musculus)

House mice are active all year round, which means you could find them invading your home or business at any time. A house mouse will eat and contaminate stored food, and transmit disease through droppings, urine, bites, as well as contact with cats, fleas and mites.

What they look like

  • Length: 5-8 inches in length, including the tail
  • Weight: ½-1 oz.
  • Fur is usually a dusty gray on top and a light gray or cream color on the stomach
  • Pointed muzzle and small eyes
  • Tails are scaly and mostly naked
  • Adult droppings are up to ¼ inch long and rod-shaped with pointed ends


  • Approximately 35 days from birth to sexual maturity
  • Gestation period is 18-21 days
  • Litter size ranges from five to eight
  • Eight litters per year
  • Life expectancy is less than one year


  • Usually live on the ground or in burrows, but can climb
  • Very inquisitive - will explore anything new or changed
  • Only eat small amounts of food at a time - particularly seeds and sweet liquids, but will eat almost anything
  • Main feeding periods are at dusk and right before dawn
  • Love dark, secluded places with plenty of privacy and comfort to nest in
harvest mouse

Western harvest mouse

(Reithrodontomys megalotis)

The Western Harvest Mouse can be found along the western border of North America, from southwestern Canada through California and Arizona, down into Mexico.

What they look like

  • Length: 6-9 inches, including the tail (which is as long as the head and body combined)
  • Weight: 0.23-0.6 oz.
  • Fur is soft and brown in color, and lighter in color on the belly and feet
  • Ears are large and hairless
  • Incisors have a groove on the surface


  • Gestation period is 24 days
  • Two to nine young per litter
  • Breeds throughout the year, except during deep winter
  • Lifespan is rarely over one year


  • Primarily a nocturnal creature
  • Spherical nests are built on the ground or in low vegetation
  • Uses tunnels and runways of other small mammals
  • May congregate in communal nests
  • Eats seeds, plants, and insects
White-Footed Mouse

White-footed mouse

(Peromyscus leucopus)

While common in the eastern United States, the White-footed Mouse can be found in the West as well, weather-permitting. They are often found in wooded areas or places where it is warm and dry.

What they look like

  • Length: 5-8 inches, including the tail
  • Weight: 0.37-1.5 oz.
  • Fur ranges from grayish to reddish brown on their back and head and is white on their belly and feet
  • Tail is covered in short hair
  • Hind feet have six pads each


  • Gestation period is 21-24 days
  • Two to six young per litter
  • Two to four litters per year
  • Lifespan is generally two to three years in the wild


  • Nocturnal creatures
  • Build nests in concealed locations
  • Will seek warmth in homes, garages, sheds, and infrequently used vehicles
  • Drums the front feet when alarmed
  • Primarily feeds on seeds, fruits, nuts, and insects

Have a mouse in your house?

Western Exterminator specialists are trained to track down mice and other rodents around your home and property. Our specialists can determine how mice are getting in and offer solutions not only to get rid of mice already in the house, but to prevent them from returning. The key to controlling mice includes sanitation, elimination of shelter, and rodent-proofing your property. This allows the setting of control measures and monitoring for population decrease. Western Exterminator specialists are well-trained in all of the most effective house mouse control solutions.

The first step is to reach out and contact your local Western Exterminator office. We'll help take care of the rest.

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