House Mouse

What is a House Mouse?

One of the more common pests found in the United States, the house mouse frequently takes up residence in homes and other manmade structures. When the rodents invade homes, they consume and contaminate foodstuffs and wreak havoc on structures and property. House mice also spread diseases such as salmonellosis and are known carriers of other vectors, such as fleas and lice.

What Do They Look Like?

house mouse

Size: The house mouse ranges in size from 5 to 7 inches long, including the 3- to 4-inch tail.

Color: House mouse fur varies in color from light brown to black, while the underbelly typically appears beige. Interestingly, the closer a house mouse lives in relation to humans, the darker the fur becomes.

Characteristics: The tail of the house mouse bears some fur and has circular rows of scales. House mice thrive in various environments and are found in and around both homes and businesses, contaminating food meant for humans and domesticated animals alike. Adult mice reproduce rapidly and tend to live around a year in the wild.

house mouse image
house mouse

House Mouse vs Deer Mouse

Where Do They Live?

Native to Central Asia, house mice found their way to North America on ships going from Europe to the New World. Distributed across the world, the rodents can be found anywhere humans are.

What Do They Eat?

House mice are omnivores with a diet focused on seeds, roots, leaves, and stems. The pests also feed on insects and other sources of meat when available. When house mice live with or near humans, they become opportune feeders that will eat any available foodstuff or household item, including glue, soap, and paper.

Problems Caused by House Mice


House mice contribute to a variety of issues in and around the home. The rodents can spread diseases that cause varying levels of sickness in humans, as well as contaminate food with their droppings.

These may be transmitted in several ways:

  • Ingesting waste left by foraging mice in pantry food.
  • Not washing hands thoroughly when cleaning up after rodents.
  • Breathing in particles of the pests’ dried droppings.

Some of these diseases have serious symptoms, so mouse infestations shouldn’t be ignored.


The rodent may cause significant aesthetic damage to property due to its propensity to nibble or gnaw on items, edible and non-edible, in search of suitable sustenance. Commonly damaged items include insulation in walls, electrical wires, and any area the house mouse nests. House mice often destroy containers and bags in houses or barns in order to reach food. In some cases, large populations of house mice may decimate crops by digging up seeds or consuming the maturing plants.

Life Cycle

Female house mice can produce between 5 and 10 litters per year, with each litter containing anywhere from 5 to 12 young. Pregnancy lasts up to 21 days until the young are born furless, blind, and helpless. Newborn house mice develop quickly, maturing to adulthood in just 6 to 10 weeks. Females are ready to mate about a month after birth, while most males reach sexual maturity two months after being born.

How Long Do They Live?

The average house mouse lifespan ranges from 4 to 20 months in the wild. Outdoors, the pests usually succumb to predators or starvation. However, inside homes house mice may live up to two years as long as they have access to shelter and food. This explains why rodent infestations are so common in residential areas.

Because these pests reproduce so quickly, the house mouse lifespan can be troublesome. It only takes baby mice about six or seven weeks to reach maturity, start mating, and cause damage.


  • Fecal pellets, urine stains, and grease trails may indicate a house mouse infestation.
  • Look for gnawing damage and tracks along baseboards.
  • Listen for audible signs, such as squeaking and scratching in walls, ceilings, attics, and crawlspaces.

Signs of Infestation


The most prevalent sign of a house mouse infestation is either seeing the rodents themselves or finding their droppings around the home.

Identifying House Mouse Droppings

house mouse poop
house mouse droppings


Secretive and able to survive with little food and water, rodents are usually first discovered by finding their waste. House mice leave behind 50 to 75 droppings a day, readily making their presence known.

House mouse feces is easy to distinguish from other pests’ poop, as it is only about one-fourth of an inch in length. These dark brown to black pellets have tapered ends.

Problems Associated with Mouse Waste

Locating mice is key to getting rid of an infestation. While the pests leave noticeable trails of waste along their favorite routes between nests and food sources, this doesn’t mean removal will be easy. House mouse droppings cause several health problems, so finding a nest is only the beginning.


Sounds of scratching, rustling, and squeaking coming from walls, attics, crawlspaces, sheds, or garages may also indicate a large incursion of mice.


Bite marks with noticeable tooth patterns prove common on wooden furniture and doors, plastic containers, hard foodstuffs, and other stored items. Homeowners may also find footprints or smudge marks in barns or dusty areas of the house where mice have traveled

Prevention Tips

Proper sanitation may help reduce the likelihood of a house mouse invasion. While no amount of sanitation will keep mice away for long if food still remains available, preventative actions like properly storing groceries and pantry items, eliminating attractive nesting sites, and sealing off points of entry to the home can help. Applying steel wool mixed with caulk around openings for pipes and wires may also help to keep mice away, as does the use of metal and concrete where necessary.

Learn how to manage a mouse infestation in your home.