The mice that commonly infest a home or garage include a number of species in the Mus genus of the Rodentia order of mammals. These small, fairly innocuous creatures are common visitors to human homes simply because these structures offer them the dark sheltering areas and food supply they need to survive. Garages are especially susceptible to infestations since mice often go overlooked here, and because food sources such as grass seeds, bird food, and pet food are often plentiful.

Considering that the house mouse is the very same species sometimes bred as a small caged pet, you might think it poses no particular problem roaming in a garage, but these small gnawing rodents can wreak a surprising amount of damage by chewing through walls, eating seed and other foods, and leaving behind excrement droppings, which can potentially spread disease.1

There are cases where entire homes are destroyed when mice chew through electrical wires and cause fires. Hence, when you hear the tell-tale gnawing or squeaking noises or see small excrement droppings, it’s time to take action.

What Do Mice Look Like?

The best-known species of mouse in the U.S. is Mus musculus, the 3- to 4-inch-long brownish house mouse with a pointed nose and long tail. There are also a number of field mice from the Apodemus genus and deer mice from the Peromyscus genus that can, under some circumstances, infest a home, garage, or outbuilding. These rodents are very similar to house mice, except for having white bellies rather than the solid-colored coat found on the house mouse.

5 Ways to Get Rid of Mice in the Garage

It can be a bit hard to feel too hostile about mice, since they are inoffensive looking creatures that look a lot like the little white mice with pink eyes that are common cage pets. These are, in fact, exactly the same species. But the reality is that wild mice are vermin pests, and in areas where there are no predatory animals (foxes, coyotes, hawks, owls, or prowling housecats) to hunt them, mouse populations can get seriously out of control, infesting an entire house.

Here are five common methods that are effective for ridding your garage of mice.

Spring Traps

Very simple in design, traditional spring traps use a triggering bait tab that loosens a spring-metal bar that snaps down on the offending rodent when it applies pressure while feeding. The iconic bait for catching mice is cheese, but almost any food substance will do. Peanut butter makes for a very good bait substance. Place the baited trap near an area where you know mice frequent, such as where you see signs of nesting or excrement droppings.

Ideally, the traps will snap down on the necks or bodies of the rodent, and death from suffocation is usually fairly painless and quick. The creatures are not crushed, as some people think.  There are instances, however, where the mouse will be caught by the leg or even tail, and here you may need to carefully dispatch the still-living mouse in another fashion.

Check the traps frequently. A dead mouse will soon announce its presence from the odor of decay, at which time it’s much less pleasant to deal with.

Sticky Traps

Using a very sticky wax-like substance, glue traps capture any mouse that wanders onto the sticky pad while in search for food. These are sometimes thought to be more humane than spring traps, but a mouse can remain for hours trapped this way, and may even chew its own paws trying to escape. And if you do trap a mouse, you’re left with then killing it anyway. It is nearly impossible to extricate a live mouse from a sticky trap.

Sticky traps appeal mostly to people who are uneasy about setting spring traps, but they are no more effective and in many ways are less humane.

Live Traps

If killing a mouse is repugnant do you, there are a variety of live traps you can use to catch them. Most designs have some method of baiting the rodent to enter, then tripping a door or hatch that traps the live mouse.

But you will then need to figure out what to do with the live mouse. Released in a residential area, and you’re just off-loading your own problem on someone else. Released in the countryside, you’re just making the mouse a burden for a farmer. If you must live-trap, perhaps releasing the rodent in the woods or another other wildlife area is the best solution, but remember that here the rodent will likely quickly become a food source for an owl, fox, or hawk. Such a fate is by no means more humane that dispatching the rodent through a traditional live trap.

Rodent Bait

A variety of poisons can be used to kill mice. Many of these use an anticoagulant substances such as warfarin, which act by causing the rodent to bleed internally, usually over the course of several days. In addition to the pain this must create for the mouse, the pellets, tabs, or bait stations can be found by pets or children, and if the substances are eaten, they can cause serious illness or even death.2

There are also other toxins used to kill mice and other rodents, and most can be quite toxic for pets and humans.3 Rodent poisons are not a good choice for homes with pets and children. Nor are they a good choice for garages, since the poisons are often carried outside, where wild animals often find them. Small predators, like foxes or owls that eat mice contaminated with poison can also be affected. All in all, poison bait is not the best choice for ridding your garage of mice.

Keep a Cat or Dog

Not just any cat or dog is a hunter that will find and kill mice. In fact, statistics show that homes with domestic pets are sometimes more likely to have mice, largely because they also contain stored pet foods.

However, the right kind of house cat, and certain dog breeds, can be very effective at catching mice. Aggressive young cats can sometimes be very skilled mousers, and many terrier species of dogs are bred specifically to catch small animals. If you’re lucky enough to have this kind of pet, give it a few hours each week of hunting time in your garage, preferably at night.

Signs of Mice in a Garage

You may need to pay close attention to catch signs of a mouse infestation in the garage, mainly because these spaces are often cluttered and because you likely don’t spend much time there. If you suspect an infestation (or see a mouse), listen for squeaking or rustling in the garage (particularly at night) and check wires, walls, and bags of feed or seed for nibble marks or other damage. You should also look out for unusual odors (like urine), holes in any materials that weren’t there before, rodent nests, or scratching or scampering noises. Check the floor along the edges of the room for droppings. If necessary, move large items the mice may be nesting under or inside to look for signs.

What Causes Mice in a Garage?

Mice are a common problem in a garage because these spaces typically have many dark places to hide and nest, often have good food and water sources, and because there are usually plenty of cracks and crevices that allow them to come and go easily. In other words, if a space was designed to shelter mice, it would look a lot like a typical garage. On the other hand, spotlessly clean, well-lit, and airtight garages will not be very attractive to mice and other rodents.

How to Prevent Mice in a Garage

Preventing mice in a garage is largely a matter of denying them their nesting and hiding areas, eliminating food and water sources, and plugging and blocking any cracks, holes, or crevices that allow them to enter. Begin your efforts at prevention by first trapping or baiting any mice already in the garage. At the same time, begin to declutter your garage and seal up holes.

• Keep food sealed or out of the garage, and put dog food, fertilizers, and grains in tightly sealed plastic containers.
• Keep the landscaping around the foundation of your home free of brush and thick layers of mulch. Carefully inspect concrete slaps and foundations for cracks, holes, and crevices, and fill these with concrete patch. With wide cracks in wood walls, stuffing them with steel wool before patching over can prevent additional gnawing.
• Commercial rodent repellant chemicals are available, but if you are leery of harsh chemicals, you can concoct a more natural mixture that mice hate. Mix two tablespoons of hot pepper sauce (the hotter the better) in a gallon of water with several drops of liquid soap. Spray it on the outside of the garage. It works just like commercial repellents and won’t harm your pets or children.
• Peppermint is a natural mouse deterrent and is environmentally safe.4 Spray a solution of peppermint extract and water around the perimeter. This solution needs to be sprayed once a week and after rainstorms. Or, you can plant peppermint around the foundation of your home and garage. The smell repels rodents and perfumes your home. (Note that, while peppermint oil can help deter mice from entering your home, it is much less effective at removing mice already living there.)
• For another eco-friendly solution, use ultrasonic mouse repellers inside the garage. An ultrasonic mouse repeller is inaudible to humans, but the sound it produces is very painful to mice. Mice will not enter a room where this device is humming.

The reality is that mice will usually find a way into a garage, and “preventing” them usually means some form of ongoing seasonal effort. In colder climates, mice will be particularly troublesome during the fall, as the rodents begin to seek warm dark areas to overwinter.

Mice vs. Rats

Another type of rodent can be an even more serious garage pest, especially in certain regions and environments where they are more prevalent. There are two species of rats that are especially problematic for human dwellings: the black rat (Rattus rattus) , also known as the house rat or roof rat; and the brown rat (Rattus norvegicus). Black rats are typically between 5 to 7 inches long, black to light gray in color, while brown rats can be 13 inches long or more, with a brown or light gray color. Certain strains of the brown rat have been domesticated as pets, especially the white varieties.

Rats can be considerably more damaging in a home or garage, and they are also carriers of disease.1 But methods for eliminating and preventing them are largely the same as for mice. Trapping requires much larger, stronger traps.

When to Call a Pro

Eliminating mice from a garage is usually easy enough, but sometimes a severe infestation is more than you can handle yourself.

If you hear mice scratching in unseen areas of the garage or within the walls, if you’re unable to trap them, or if you continue to see droppings after all methods have been tried, it’s time to call a professional exterminator. A professional can help you identify how the mice are entering your garage and can swiftly resolve your issues faster than a do-it-yourself approach. Even better: They can offer solutions that are both pet- and family-friendly.