12 Common Questions and Answers About Mice in the House

How Do You Know if You Have Mice?

Although the most obvious sign of mice is actually seeing live or dead mice in your house, there are plenty of other signs that can tell you a mouse infestation might be building. These include:

• Gnawed holes in stored foods, piled papers, insulation, etc.
• Food scraps or wrappings left behind, especially in out-of-the-way places, such as inside shoes or boots or in the corners of closets and cabinets
• Droppings or tiny hairs
• Runways—narrow pathways where dust and dirt have been swept clean, noticeable grease marks, or urine trails that can be seen under a black light
• Nests or piled nesting materials
• Skittering or scratching sounds coming from wall, ceiling, or floor cavities
• Stale, rank, or musty odors

How Do You Know if It's a Mouse or a Rat?

There are key differences between mice and rats. Mice are much smaller than rats. Adult mice are about 7 1/2 inches in length, including the tail. The most common rats in the United States are the Norway rat and the roof rat. They can be anywhere from 13 to 18 inches in length, with tail length varying by species.

What Do Mice Eat?

Mice most prefer to eat cereal grains and plants, but they will feed on almost anything. They are very commonly drawn to dried (and bagged) stored food, including pet food.

How Long Do Mice Live?

A house mouse will rarely live more than a year in the wild. But in a protected environment with food and water (such as a house), it can live up to two years and possibly more.

Do You Keep Finding Shredded Paper and Black Rice-Like Things?

If you encounter shredded paper, you have likely found a mouse nest. A mouse will build its nest from just about any soft material or finely shredded paper. And the little black "rice" is most likely mouse droppings.

Where Should You Put Mouse Traps?

Mouse traps should be placed where the mice are. If you have found any signs of mice—shredded paper or cloth, droppings, urine stains, and gnawed items—place the traps in those areas. Traps are available from home and garden stores or even some grocery stores. Many can be reused, while others are intended to hide the trapped mouse from view and be used only once.

What if Your Traps Aren't Working?

Mice are very curious and will investigate new things. So if mice are not caught within the first days of trap placement, the trap (or mouse bait) is probably in the wrong place and should be moved. Place the trap where any signs of mice are seen or where food or water is available.

What Is the Best Bait for Mouse Traps?

Contrary to popular belief, cheese is not the best bait to use in traps. Peanut butter can be very attractive to mice, but it needs to be replaced if it gets too dry or hard. Other good options are bacon, nuts, dried food, and sticky candies. The bait should be securely attached to the trap trigger, so the rodent can't simply pluck it off and walk away. Often, a small amount of peanut butter worked into the crevices or cup of a trap is the most effective bait. Mice are attracted to the smell and will have to work to get the food out of the bait, setting off the trap.

Why Are You Not Seeing the Mice?

Mice are nocturnal creatures, so they are most active between dusk and dawn. They don't usually like bright lights, but a mouse might sometimes be seen during the day, especially if its nest has been disturbed or it is seeking food. Seeing mice in the day also can indicate a large infestation in a home.

How Quickly Do Mice Breed?

In a single year, one female mouse can breed up to eight litters of five to six young. These 40+ offspring can begin to reproduce themselves in as little as six weeks. So within months, you could have a huge population of mice.

How Do Mice Get Inside a Home?

A mouse can slip through holes and gaps as small as 1/4 inch, or roughly the size of a pencil. And if an opening is not big enough to squeeze through, the mouse can gnaw it until it is big enough. Mice also can jump 13 inches high and can run along wires, cables, and ropes. They are excellent jumpers, swimmers, and climbers and can scale rough and vertical surfaces.

What Can You Do to Get Rid of Mice in Your Home?

There are a number of methods of control, including traps, baits, rodenticides, and professional pest control. However, trapping is generally the best and safest method for homeowners to attempt. Traps can be used to kill the mice, or they can contain the animals for relocation.

In addition to trapping, it's a good idea to exclude mice from the home by sealing openings around pipes, roof vents, and other potential entry points. Keeping a few traps set in likely nesting areas or entry points for mice, such as the garage, can provide early detection of mouse intrusion.