Dealing with house mice can be incredibly stressful, especially when you can tell the issue is getting worse, but you can't figure out where the mice are coming from. Mice create sanitation issues and can spread disease. They cause structural damage by chewing holes and attract other rodents with their smell and mess. Mice destroy stored goods and products with their urine and droppings and leave debris and chewed nesting materials scattered about their favorite hiding places. So anyone will agree that having unwelcome mice in the house is a big problem, but what do you do when you suspect you have a mouse infestation?
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First, identify what might be attracting the mice and how they're entering your home, then follow our guide to getting rid of mice and deal with this pest issue for good.
Mice and other rodents spread a variety of viral and bacterial diseases. If you are dealing with a rodent issue, even if you are just cleaning up a space that has had rodent activity inside, wear gloves and an approved mask or respirator to protect yourself.
What Do Mice Look Like?
Mice are small mammals with long tails (which can even be as long as or longer than the mouse's body), large eyes, fur on their bodies, and large ears. When fully grown, they are typically about 7 1/2 inches in length including the tail, though actual size will vary by type of mouse. Many species of mice are common in the U.S., including the house mouse (Mus musculus), deer mouse (Peromyscus maniculatus), the white-footed mouse (Peromyscus leucopus), and various species of field mouse from the Apodemus genus.
Mice are tiny and can squeeze through holes as small around as a dime! They also do not stray far from their nesting sites, meaning that if you are finding mouse activity inside, they are likely nesting somewhere nearby, either inside or in the yard.
4 Ways to Get Rid of Mice
Seal Entry Points
When rodents are accessing the inside of your space, it is important to find where they are entering and seal those spaces up. While many DIYers would run for a can of spray foam in this instance, this is not ideal. Spray foam may fill the space, but mice and rats can easily chew right through it, making re-entry a breeze. Instead, use some sort of metal sheet or mesh and screw it in place.
Modify Their Habitat
When attempting to get control of a mouse issue, ask yourself what is attracting them to your property in the first place.
- Is your yard providing mice with easy access to food or water?
- Where are the mice seeking shelter or nesting?
By determining where the mice could be feeding, finding water, and hiding, you can start to change these factors to make the environment around your home less desirable to these unwanted visitors. Cut back ivy and vegetation where mice could be hiding, make sure that you aren't leaving food around for them to enjoy, and turn off irrigation systems when not in use to reduce water sources.
Set Snap Traps
Some people have no desire to try and trap rodents themselves, but if you're trying to manage a severe mouse infestation on your own, there may be no choice. Snap traps can be used for mice, but make sure that the mouse traps you are buying are special mouse snap traps and not rat traps. Rat snap traps are too big for mice.
Try Glue Trays
The other traps to consider when controlling mice are glue trays. These can be controversial, as they are not as quick and humane as snap traps. They can also scare mice that are caught live, causing them to urinate and further expose you to disease. That being said, snap traps only have the ability to catch one animal at a time and require emptying and resetting. When using glue trays to control severe mouse infestations, it is not uncommon to find multiple mice on just one tray, making these very effective traps for mice.
When it comes to rodents, there are two primary pieces of evidence you're looking (and listening) for: scratching sounds and droppings.
If you're sitting on the couch reading or lying in bed at night and you hear a scratching or scurrying sound from inside the walls, this could indicate the presence of an animal in your space. Sounds in the walls or attic don't always mean rodents. It could also be squirrels, birds, or even yellow jackets, so you'll need to do some further investigating to figure out what's causing the issue.
If you are finding droppings in your garage, pantry, or other spaces, this is definitely an indicator that an animal is coming in and looking to help themselves to whatever they need.
Animal droppings can actually tell you a lot about what pest is present around your home. If you find droppings that you think belong to a rodent, compare one to a grain of rice. Mouse droppings are significantly smaller than a grain of rice. If the dropping is close to the same size or larger than the grain of rice, you are likely dealing with a rat issue.
What Causes a Mouse Infestation?
Like it or not, mice and other rodents are an important part of a healthy eco-system, and they will likely be present around your home. If you are seeing evidence of mice, consider what could be attracting them to your home. Do you have bird feeders around that are providing them food? Could they easily find water in your yard? Is there dense vegetation against the foundation of your house that gives them a place to hide against the house?
Mice and other rodents are also incredibly sensitive to air flow, especially in the fall and winter. If mice are running around the perimeter of your house and there is a gap that is allowing air from inside to flow outside, they will want to follow this airflow because it leads somewhere warmer and food could be present. Seal up gaps along the foundation of your home, make sure rodents can't feel air flowing from inside, and be sure to close all doors (including garage doors), especially at night.
How to Prevent Mice From Entering Your Home
The best prevention against mice is to maintain a well-kept home. Make sure crumbs are swept up and store food in sealed containers. Also pay attention to your home's exterior and seal up holes and cracks—anything that may allow a mouse into your house—promptly.
It may seem obvious, but the first and most important step in solving any pest issue is identifying what specific pest is causing the problem. Rats and mice cause similar damage, but they look and behave differently, and it can be important to know these differences if you are trying to address a rodent issue.
Mice are significantly smaller than rats, and so are the holes and burrows they make. Mice are more likely to come inside the living space than rats are, and they also nest in larger numbers than rats. They are also not as neophobic as rats, which can make controlling them with trapping easier and more productive than trapping rats.
What Is Neophobia?
Neophobia is the fear of new or unfamiliar things. Rats are incredibly neophobic, which can make controlling them difficult, as they are very sensitive to changes in their environment and are likely to be suspicious of newly placed control methods. Mice, on the other hand, are considered more curious and do not become wary of new things the same way rats do.
Rats, unlike mice, have a larger wandering range and will come and go from a variety of places. If you are dealing with rats, they could be nesting anywhere nearby. Rats are significantly larger than mice and leave holes that range in size from a half dollar to a baseball. Rats do not nest in the large numbers that mice do, as they are territorial once they reach adulthood. Their smaller numbers and wariness of new things can make it difficult to entice them to enter a trap.
Smaller than rats
Can fit into holes as small as dimes
Don't wander far from nest
Nest in larger numbers
Larger than mice
Can fit into holes as small as half-dollars
Wander far from nest
Nest in smaller numbers
Afraid of new things
Where do mice come from?
Mice are all around us, hiding in plain sight. This is especially true if you live in an area that is heavily wooded, has lots of vegetation, or backs a greenbelt.
Will mice go away on their own?
If there are mice present in your home, it is highly unlikely that they will go away on their own. Try to address and change what is attracting them to your property, including food, water, and harborage sources.
How long do mice live?
The average lifespan of a mouse is anywhere from 12 to 18 months. Mice reproduce rapidly, meaning that even when the initial mice causing the issue are gone, there will be plenty of offspring left behind.
When to Call a Pro
There are a number of reasons to call a professional for a mouse issue. Maybe you have no interest in trying to eliminate the mice yourself, or perhaps you've already tried and can't seem to get a handle on the problem. If there is a mouse situation that is so severe it feels like chemical control (poison) is necessary, definitely call an IPM professional.
While mouse and rodent baits are available at the hardware store, there are a number of risks that come with improper use of rodenticides (poisons designed for rodents), especially if entry points around the home have not been sealed adequately. These risks include:
- Pets and children coming in contact and/or ingesting the product
- Neighborhood wildlife and pets being harmed by the product
- A rodent feeding on bait, climbing into an open entry point, and dying in a wall void, creating smell and potential fly infestation issues
It is important that mouse poison is used correctly. Professional pest control experts should be putting rodenticide blocks in a locking station that is anchored in place. These stations encourage rodent feeding while keeping bait locked away from people and pets. When poison baits are left in the open where children or other animals can access it, the results can be catastrophic.
Diseases Directly Transmitted by Rodents. Centers for Disease Control and Prevention.
Controlling House Mice. UM Extension.
Trap Up! Centers for Disease Control and Prevention.
Modlinska, Klaudia, and Rafał Stryjek. Food Neophobia in Wild Rats (Rattus norvegicus) Inhabiting a Changeable Environment-A Field Study. PloS one, vol. 11, no. 6, 2016. doi:10.1371/journal.pone.0156741
Can Rodenticides Hurt Kids and Pets? National Pesticide Information Center.