Everything to Know About House Mice

Updated: Mar. 22, 2024

House mice are pests in every part of the world. We asked a biologist for tips on identifying and handling an infestation of these pesky critters.

Where I live in California, mice are considered a major hazard. It’s not just for what they do inside houses, which is problematic enough, but also for what they do to cars. My friend recently spent more than $2,000 to repair her mouse-infested car for the second time in three years. The mice made nests inside the air vents, chewed through wires and, of course, left droppings and debris everywhere. Be sure to read up about different types of mice.

Mice damage homes just as extensively. But because it’s usually behind the walls, it’s not as noticeable. To mice, fiberglass and cellulose insulation make ideal nesting materials, and plastic wire insulation is a tempting treat.

Once house mice move into a home, they become a constant presence in the kitchen and other food areas, sometimes even taking up residence in the oven if it isn’t used often enough. That also happened to my friend. She ended up discarding the oven to avoid serving mouse-flavored casseroles.

To get the lowdown on these pesky rodents, we consulted Meg Pearson, training manager at Critter Control. She reminded us mice don’t just live behind the walls. “It’s not uncommon to also find mice in attics, crawlspaces and garages,” she says. Also cars, storage sheds, RVs and virtually any other warm, sheltered space on your property.

What Are House Mice?

Yes, there’s an actual species called the house mouse. It’s the most common mouse species in the world, found on every continent except Antarctica.

“The house mouse is also known as the Mus musculus,” says Pearson. “It is known for its large ears, pointed snout and virtually hairless tail.”

House mice are constantly looking for food. Although they prefer grain-based products, they’ll eat virtually anything humans eat. They’re so similar to humans in so many respects that they’re the preferred subjects for biomedical research.

Although the house mouse is most likely to cause an infestation, two other species are also known to nest inside houses, especially during the winter.

The deer mouse, aka the field mouse, is slightly larger than a house mouse, with a more slender and angular body and head. The other is the white-footed mouse, aka the wood mouse. Known for its white feet (hence the name), it’s smaller than a deer mouse. Both prefer the outdoors and rarely cause as much damage as the house mouse.

What Attracts Mice to Your Home?

In the winter, warmth. All other times of the year, they’re looking for shelter from predators.

Because our forested property is home to owls, bobcats, foxes and red-tailed hawks — all of whom prey on mice — we have pests indoors at any given time, despite our ongoing control efforts.

Once mice enter a house and feel safe, they start searching for food. “Mice are always attracted to kitchens, and we highly recommend storing all food in airtight containers for this reason,” Pearson says. “Mice will also gnaw on virtually any surface or material to get into a home, such as insulation, wiring and wood.”

You’ll also hear mice running and chewing behind the walls or in the ceiling.

Do House Mice Bite?

House mice gnaw, that’s for sure. But bite humans? Not really. Although they will defend themselves when cornered, house mice generally avoid humans altogether. When you go to bed, in the highly unlikely event a mouse finds you, it’s even more unlikely it will bite you.

The chances of getting bitten are not zero, however. House mice carry pathogens that cause diseases such as:

  • Hantavirus;
  • Hemorrhagic fever;
  • Leptospirosis;
  • Lymphocytic chorio-meningitis;
  • Salmonellosis.

If you’re bitten, clean and disinfect the wound ASAP. Seek medical attention immediately if you notice signs of infection like fever, heat or redness around the wound, or swollen lymph nodes in your neck, groin or armpits.

Signs of a Mouse Infestation

Mice are adept at hiding because their survival depends on it, but must emerge at some point to eat. That usually happens at night, and they leave copious evidence of their activity.

Tell-tale signs of a mouse infestation include mouse dropping sightings, damaged insulation, stripped electrical wires and gnawed PVC pipes,” says Pearson. “The homeowner may also see the mice throughout their house!”

If mice move into your vehicle, you might not know until you open the hood. They often make nests in crevices on top of the engine block with under-padding from the seats.

They usually run away when you start the engine, but sometimes they retreat into the air circulation ducts. Once when I stopped at a stop sign, a mouse emerged from the intake vent on the hood and perched on the windshield wiper.

How To Get Rid of House Mice

For Pearson, mouse control is a job for the pros.

“The first step is to have a wildlife control professional come to your home and remove all rodents from your property,” she says. “Mice trapping typically lasts five to 14 days, but that can change depending on the size of the house and how well established the mice are.”

For the DIY-minded, trapping is the best control method. We prefer live traps and relocating the mice to a state park far from any houses they could re-infest. If you choose this route, check the traps daily to prevent the mice you catch from dying.

Some people would rather dispatch the critters quickly. For them, snap traps are easier to use and more effective than the old wire traps. Avoid poisons because the mouse dies slowly, and any animal that eats the carcass will be poisoned as well.

How To Prevent House Mice From Coming Back

“The most effective mouse control method is exclusion repairs,” Pearson says. “This involves sealing off any current or possible entry points on the home, followed by a thorough inspection and sanitation process.”

Be sure to keep your house as clean and free of food scraps as possible. Finally, Pearson says, “It’s important to repair any damage the mice may have done to the house, and disinfect any areas with mouse droppings.”