If You See One Mouse, How Many Do You Have?

Q: While my family and I were on vacation, our living room security camera caught a mouse scurrying over the couch. Now I’m wondering if you see one mouse, how many do you have?

A: If a homeowner spots one mouse in their house, likely, there are at least a few more where that one came from. While there are several ways to gauge the number of mice hiding out in a home, the time of day of the mouse spotting could be a helpful first indicator. If the occurrence happened during the day, there are probably at least several more mice. Mice usually keep to themselves and are nocturnal, so movement in the daytime may indicate their nest is overcrowded.

Having mice in your home is a common problem many homeowners face, and there are potential solutions to help drive them out. It can be overwhelming, and thoughts can spiral if you see one mouse and wonder how many do you have. However, it may take patience to solve a mouse infestation completely.

A single mouse is a rare occurrence, but the mouse might be alone if the weather has been cold.

On average, most mouse sightings indicate a more significant infestation, so having a solitary mouse in your home is pretty rare. However, this may be the case if the weather was particularly cold several days prior and there have only been a few mouse droppings. The mouse may have somehow wandered inside looking for food or shelter or was fleeing a pursuing predator.

Keep in mind that mice can have litters up to 10 times a year so that one mouse can turn into many quite quickly if even just one more entered the home with it. It’s best to keep an eye out for signs of a larger infestation.

If you see a mouse at night or in a low-traffic area of the home, you likely have many more nearby.

Mice are nocturnal. They prefer to be active at night in low-traffic areas—especially in homes—because there is less of a chance of harm from predators.

Mice can produce litters as quickly as every 20 days with consistent litters of at least six mice. One mouse can turn into 127 mice in 150 days (about 5 months) if the infestation is left unchecked. For homeowners who suspect mice may be in their walls, attics, or crawl spaces, it’s essential to look for additional evidence to confirm the presence of mice.

Mouse droppings are sure signs of mouse presence.

Homeowners with a mouse infestation are likely to come across mouse droppings. Droppings are usually found in several places: near mice nests or where they live, near food sources, and around usual paths to and from the nest or food source.

Mouse droppings are very small cylindrical shapes that almost look like dark brown or black rice grains, and they’re pointed on both ends. These droppings can carry diseases like hantavirus or listeria, so it’s important to clean them up quickly and address a potential mouse problem as soon as possible.

Scratching or rustling in the walls can indicate a mouse infestation.

Even if physical evidence like mouse droppings isn’t present, scratching or rustling in the walls, especially after sunset, can be a sure sign that mice are in a home. Pets can also alert their owners to mouse infestations with their great hearing—if a dog or cat starts staring at, barking, or growling at walls for no apparent reason, trust their instincts and call in a professional to confirm suspicions.

Mice can squeeze through the tiniest holes to get to shelter and barely make a sound while doing so. An adolescent mouse can fit its body through a hole that’s the width of a pen. If a mouse sees a hole that’s not big enough, it will use its teeth to widen it and nest.

Why do mice take up residence in walls and air ducts? It all has to do with safety and security. Mice keep to low traffic areas and prefer darkness to bright or harsh light. As such, the small rodent finds safety from predators, an unimpeded way to get around to food and nesting supplies, and comforting darkness in the walls of a home.

Look for signs of a mouse nest, which may help determine how long mice have been in the home.

As foragers, mice build nests out of what they can find around them. Not only are mice skilled at hide-and-seek from larger predators and foraging for food supplies, but they can also chew through a large variety of building materials, including drywall, insulation, rubber, and even power lines!

If you scour your house—especially basements, garages, crawl spaces, and attics—and can’t find a mouse nest, it means the mouse or mice haven’t been in your home long enough to build a nest.

Mouse nests are made of materials like paper, cardboard, bits of insulation, and other soft materials to build their nests, and they are not orderly housekeepers. Looking for mouse droppings, bits of food, and urine can make finding a mouse nest easier.

Places mice like to nest are somewhere that is safe from predators (especially if a home has cats), is dry and warm (especially during the winter), offers enough nesting materials, and has easy access to a food source.

Professionals are best equipped to handle a mice infestation of any size.

Not only do mice reproduce at an alarming rate, but their bodies and droppings carry disease—and one mouse can produce 50 to 75 droppings a day. As mentioned above, hantavirus is one of the main diseases mice can carry, which presents with flu-like symptoms but can become potentially life-threatening. In addition, mice can chew through wires and start electrical fires, putting a home and its inhabitants at risk.

While homeowners can usually handle the responsibility of identifying a mouse infestation, pest control professionals are equipped to identify and rid homes of mouse infestations in the safest way possible for all parties.

If homeowners suspect a mouse infestation based on mouse dropping sightings, scratching in the walls during the night, or seeing one or more mice in person, it’s best to call an exterminator or pest control company to eradicate the problem adequately.