The Essential Guide to Mice

Mice have been around for centuries. While their size has varied throughout history, mice have proven to be very adaptable to climates and terrain. Every single continent has mice save for Antarctica because it’s too cold there, even for a mouse.

Mice have long been a pest for humans. They are notorious for making messes, chewing through walls and creating other annoyances around homes and businesses, not to mention causing damage to everything from crops to physical structures. Mice have also been connected to various diseases throughout history and continue to be a problem, especially as humans expand further and further into mice’s preferred wilderness territories.

If you have ever had the experience of seeing a small gray creature run past you in the middle of the night or heard these rodents chewing away on furniture or within the walls, you know the dread of a mouse infestation. Ehrlich Pest Control understands how mice get inside houses and what damage they can do. Below, we provide answers to some of the most common mouse questions we have been asked.

If you think you have a mouse infestation, contact your local Ehrlich Pest Control office today and discuss our mouse treatment and prevention plans.

Basic mouse questions

• What is a mouse?

• What do mice look like?

• What do mice eat?

• What sounds do mice make? When mice squeak, what does it mean?

• When do mice sleep?

• Where do mice live in the wild? Where do mice build their nests? Where do mice hide?

• When do mice have babies? When do mice breed?

• How smart are mice?

• What animals eat mice?

Mice as pests

• How do mice get into houses? Why are mice in the house?

• How do mice end up in the toilet?

• What do mice sound like in the walls?

• How do mice climb walls?

• Do mice bite? When do mice bite?

• Why are mice dangerous? Why are mice bad? What diseases do mice carry?

• How do mice spread disease?

• Why do mice chew wires?

Mouse control and prevention

• How do you get rid of mice? How do you trap mice? How do mice avoid traps?

• How do you prevent mice in the house? How do you keep mice away? What repels mice?

Basic mouse questions

What is a mouse

Mice are, in the simplest terms, rodents. They are characterized by being very small, especially when compared to other common urban rodents like rats. The singular for mice is mouse. These rodents are generally found within the order Rodentia, within the genus Mus.

Mice are one of the most common and numerous pests in the world. Most of the time, mice prefer to live in the wild but have easily adapted to urban environments. They are also common pets, but also used for medical experiments due to their genes having such similarities to that of humans. Mice are also common prey for a number of predators and are even sometimes sold as food for certain pets like snakes in pet stores.

Most species of mice are nocturnal, which is why you don’t often see or hear them around your home or property during the day. Instead, you can often hear them get active in walls, across floors, chewing or moving about at night. Because the mouse has been proven adaptable to so many environments it is considered one of the most successful mammals on the planet.

What do mice look like?

Often confused for rats, mice are usually very small, furry rodents. Generally, mice have pointed snouts, large, mostly hairless ears, small black eyes, tiny paws and a scaly tail which is usually longer than their body. Mice are also characterized by their tendency to breed very fast. Mice come in a variety of colors. Most of the common mice found in North American homes are gray or brown with whitish fur on their stomachs. However, there are black and white mice, although most mice of unique colors are found in pet stores or for medical uses. Some albino mice also have totally white bodies with reddish eyes, although these are very uncommon. Mice usually get to be about three inches in length in terms of their bodies, but they have tails that are as long or longer than their bodies. The sizes and shapes of mice bodies can vary based upon species.

Most species of mice are nocturnal, which is why you don’t often see or hear them around your home or property during the day. Instead, you can often hear them get active in walls, across floors, chewing or moving about at night. Because the mouse has been proven adaptable to so many environments it is considered one of the most successful mammals on the planet.

What do mice eat?

Mice in the wild are generally herbivores, which means they eat plants and plant material. They prefer to eat things like grains and fruit. This is why mice are such a threat to agriculture and those within the farming and food processing industry.

While this is true of most wild mice, mice have adapted their diets as well as their appearance to suit almost any environment. As urban sprawl has put more and more humans, buildings and homes in the territory usually housing wild mice, the typical mouse has adapted their diets. They have become omnivorous in urban settings and have been known to eat meats. Mice who find their way into a home will devour just about anything they can get their tiny paws and sharp teeth on or into. In fact, it has been documented in cases where the mouse infestation is so large that food has become scarce mice will even eat each other.

What sounds do mice make? When mice squeak, what does it mean?

Like many animals, mice are known to vocalize (make noise) for a variety of reasons. Mice will make sounds often described as "squeaking" to convey a number of things. The squeaks change in pitch and intensity, as well as volume, depending on what these rodents are trying to convey. A mouse may be trying to find out if there are other, friendly, mice nearby. They may be indicating they have found food to others within their nest or family. Mice make louder and faster squeaking sounds when mating and will also alert to danger.

Mice also make scratching and chewing sounds. Mice have very poor eyesight, so they stay close to the perimeter of the room, near the baseboards. Often, homeowners who hear scratching noises along walls are hearing the tiny claws of the mouse as they scurry along the wood. Mice also make noise when climbing up or down inside of walls.

Mice also have sharp teeth and have a compulsion to chew, much like rats, gophers and other rodents. Mice will chew through fabric, plastic, as well as wood. Mice also use their teeth to chew up suitable nesting materials they use to raise their young. Sometimes mice chew loudly and this can be heard quite clearly within a home or building.

Since mice are nocturnal, most of the time homeowners realize they have a mouse problem when they are trying to sleep, which can be very disconcerting.

When do mice sleep?

Mice are nocturnal, which means they come out at night. This is why pet mice are often active and run around their cages at night more than they do during the day. This means mice sleep in their nests and burrows during the day.

Where do mice live in the wild? Where do mice build their nests? Where do mice hide?

When in the wild, mice will build their nests just about anywhere they can find a place with warmth and where they can nestle down, hide food, breed, and raise their young. Some mice build burrows, where they dig down below the soil and then find materials such as grass, moss and other substances they can use to create soft nesting areas. Some other species of mice also build nests in rocks or areas thick with weeds, which is why it is so critical homeowners keep vegetation away from their homes.

Once inside a home, mice can build nests in just about any alcove, niche or hidden area. They will shred up paper or other substances they find around the house to build nests. Some house mice build ball-shaped nests out of torn or shredded paper and fabric. They can hide in walls, behind kitchen appliances, in attics, in basements, hidden among boxes, within furniture, in closets or anywhere.

It's important to know that mice have very limited eyesight, so they will build their nests and breed where they can easily access food. This is why kitchens, pantries, cupboards and other areas around food preparation areas are such hot spots for mice infestations. If you find mice around your kitchen, make sure you look in any hiding spot nearby. To make sure you have the entire area reviewed, call in professionals.

When do mice have babies? When do mice breed?

The thing about mice is that they, unlike most mammals around the world, do not have a standard or set breeding season. Female mice become fertile at just six weeks of age. If the rodents have found a nice cozy place to nest and easy access to food, they will just breed whenever they want. Each female offspring then becomes ready to have babies when they are six weeks old. The female mouse can have up to 5 or 6 babies in a litter. You can easily see how quickly just a couple of mice can quickly become a full-on infestation throughout a house or property. The average length of a female mouse's pregnancy is just 19 days, so they get pregnant fast, give birth fast, and can be ready to have more babies very quickly, too.

This is why calling in a professional in mouse control to come in and remove the mice which are already present and prevent them from returning. Missing just a couple of rodents can quickly become a new infestation.

How smart are mice?

The key element to remember when thinking about mouse intelligence is that you cannot measure it in the same way you do for humans. There is no IQ for a mouse and no test which can definitively demonstrate such a thing.

Works of fiction have been created where mice are listed as among the smartest creatures in the universe, but this is not really true. Your average mouse is not likely to be smarter than a human, for example.

However, mice can be very smart. They are curious, social, playful and can even be taught to respond to their name. In fact, a mouse can even be trained to respond to his or her name, sit up and ask for a treat. Mice can also be trained to perform simple tasks and tricks.

One of the key things to remember when determining intelligence has to do with the size of the living creature compared to the size of their brain. Humans have, roughly, a 1 to 40 ratio in terms of body weight compared to brain weight. Mice have roughly the same ratio, which indicates mice are generally fairly intelligent creatures.

Mice are regularly studied in labs. It has been demonstrated that mice can solve rudimentary problems. They also have to think quickly since they need to use their intelligence to avoid predators and dangers.

This is why mice can be very good at hiding. They can also be very good at resolving issues, including rebuilding nests. Removing rodents such as mice can be a challenge.

What animals eat mice?

Mice are the preferred prey of a number of different species of predators. In fact, in some areas of the world, mice are eaten by humans, too. However, the number of species that consume mice and other small rodents is large, which is why mice in the wild prefer to build nests below ground and will try to get inside homes and buildings. It is safer to be inside than outside, and it's safer to be out foraging for food at night than during the day.

There are a number of mouse predators in the wild and they are in a number of different species. Here is a list of some of the animals which prefer to eat mice:

• Birds - raptor birds such as hawks, eagles, falcons, and owls are very fond of eating small rodents such as mice. If you want to know if there are mice in a field near a home, seeing a large number of hawks, falcons or other predatory birds can be an indication. Of course, owls are also famously nocturnal, so even nighttime is not safe for mice in the wild.

• Mammals - there are a large number of other mammals which prefer to devour mice. Cats are probably the most famous mouse-eaters. Some wild canine mammals like foxes, wolves, coyotes will gladly snack on mice. Weasels and ferrets are also known to eat mice and people who keep ferrets as pets often feed them dead mice purchased from pet supply stores.

• Reptiles - snakes and lizards of all sizes and species love to snack on mice. Most species of reptiles eat mice whole, swallowing them entirely. Snakes will often strike their prey, paralyzing or killing them before they are consumed. Again pet snakes are often fed live mice purchased from pet stores and will often not eat anything else.

For pet owners, it's not really advisable to let cats and other domestic animals just feast on wild mice. Wild mice can carry a number of parasites and these can be ingested or consumed by the pet. Thus, cats who are allowed to play with or eat mice can end up with health problems from doing so. Mice bought from pet shops are more advisable and safer.

Mice as pests

How do mice get into houses? Why are mice in the house?

Mice have very unique bodies. They are small to start with and have collapsible skeletons. This allows them to compress their bodies small enough to squeeze through even the tiniest openings. In fact, mice can easily claw and pull their way through holes that are no bigger than the width of a pencil.

Mice will take advantage of any opening to get inside homes and properties. They will crawl beneath garage doors, exterior doors of any kind. They will also come in via screens with holes, holes in siding. Mice will crawl into chimneys, vents, and holes in walls created by cables and wires which extend from inside to the outside. Mice have been known to crawl into attics from loose and broken roof tiles and into basements from drains. Although mice are not quite as good at swimming as rats, they can swim into toilets and basement bathrooms.

The reason mice come into homes and properties is the same reason they will make burrows when left in the wild. They are looking for shelter, food and a safe place to create nests and have their young. Mice will try to find hidden areas in which to build their nests and, if necessary, will chew their way through wood and drywall to get inside.

How do mice end up in the toilet?

Mice will use any access point they can find in order to try and get inside home and property. Their larger rodent cousins, rats, are probably more famous for being able to hold their breath and swim up into homes via basement bathrooms. Mice can still swim and depending on the amount of water within the pipes and toilets, can also find their way inside basement bathrooms through the toilets and pipes. It is much rarer, but not impossible. Mice can be very good climbers and will use pipes and vents to get into homes and even up to upper floors.

What do mice sound like in the walls?

Mice will get in between walls and use their tiny claws to climb up and down between them. This is often one of the signs homeowners will hear and confirm they have mice. The sound of scratching and chewing is usually heard and often at night, which most homeowners find disturbing and upsetting. Thus, the sound of scampering, clawing and chewing on wood is what it sounds like when mice are between the walls.

How do mice climb walls?

Mice have large teeth which continue to grow throughout their lives, just like rats, gophers, and other rodents. Because of this, they are compelled to chew. Since mice, by their nature, are also burrowers, they have powerful front legs and tiny claws.

So, how do mice climb walls? They use their powerful teeth to chew through wood and even siding to gain access to the space between walls. Then, with the help of their claws, they climb. These claws are strong enough to dig into softer substances, such as wood, to reach higher levels. Remarkably, mice can even use their claws to climb metal surfaces, like air ducts or vents, making them incredibly versatile climbers.

Do mice bite? When do mice bite?

It must be stated that mice biting humans is very, very rare. It takes a lot to get mice to bite you and they do not go out looking for people to chew on. The chances of being bitten by a mouse are very small and will likely only happen if you handle them by holding them or pulling them out of their nests. Thus, the real way to get bitten by mice is to corner them and leave them no option but to use their teeth to try and get away.

Mice have very sharp, powerful teeth. They are constantly growing and mice have to gnaw and chew to keep them from becoming lethal to themselves. This means their teeth are very sharp and very strong and can easily chew through wood, siding, and soft metals. This is to say that being bitten by a mouse can definitely break the skin, causing bleeding and infection. Mice are far from clean and a wound by a mouse can be infected with bacteria and there are known health risks associated with rodent bites of both rats and mice.

Why are mice dangerous? Why are mice bad? What diseases do mice carry?

It's never a good thing to have mice around. They are messy and cause property damage. They leave behind feces and urine. The problem is that mice are infested with pests and bacteria which can transmit disease to humans. In fact, there are numerous health risks associated with mice which is what makes them risky and dangerous to have around your home or property.

Some diseases linked directly to mouse feces, urine or bites include:

• Hantavirus - a potentially life-threatening illness connected specifically to deer mice. It's found in rodent urine and feces but doesn't make the rodent carriers sick. Humans who come into contact with the urine or feces can catch the virus. Since the feces can dry out and become dust particles, inhaling the virus can be transmitted that way, too.

• Salmonella - probably most often you hear about this one when a serious bout of food poisoning breaks out at a local restaurant. However, mice are known transmitters of this potentially life-threatening bacterial infection. This is because mice and other rodents crawl over food surfaces and the bacteria can end up in food. The symptoms can be serious and severe with vomiting and diarrhea.

Mice also carry ticks and parasites which can jump to humans and transmit diseases, too, such as:

• Lyme disease - which can cause serious, life-long, illnesses and health detriments.

• Colorado Tick Fever - this is a potentially serious illness that usually hits people in two stages. Symptoms include a fever, chills, headache, muscle pain and more for about three days. Then, the symptoms seem to go away, only to come back for an additional three days. The virus can also sit in the bloodstream for up to 120 before becoming active.

• Rickettsialpox - transmitted by mites which can be found on mice and who have no problem jumping to humans and biting them. It is a relatively mild illness with the first symptom being a bump around the bite area. Over time, the bump becomes a black, crusty scab and then flu-like symptoms of fever and chills. Sometimes a rash breaks out and can eventually cover the entire body.

• Babesiosis - another infection that ticks can transmit to humans. Flu-like symptoms are common and can be mild to moderate in strength. When the symptoms become severe, it can resemble and be as bad as malaria.

Mice are also known to be a potential fire hazard because they will gladly chew the insulation off of wires they find between the walls or within electronics. This can create a risk of shorting out wires and creating sparks which can ignite dry timber or the shredded paper the mice have used for their nests and cause a dangerous situation.

How do mice spread disease?

Mice spread disease a number of ways.

1. Feces and urine - mice urinate and defecate where they live. The urine and feces mixture is tarry and nasty and it contains all kinds of bacteria and virus. The feces and urine can also dry and turn into a fine dust which just walking past can kick up and make airborne. This can be inhaled and transmit disease.

2. Bites - very rare, but if they do happen, they can transmit illnesses. This is why handling mice without gloves and protection is not wise.

3. Food surface contamination - since mice often walk through dirty areas such as dumpsters and garbage, they easily pick up viruses and bacteria on their paws. Mice are looking for food and at night will walk across kitchen counters, stovetops and food preparation areas. This can transmit the bacteria into food and then into humans.

4. Parasite transmission - mice often carry mites and ticks. The mites and ticks feed on blood and will gladly jump from the mice to humans and become vectors of diseases they can pick up from the mice.

This is why mice need to be removed from homes and properties as quickly as possible. They carry with them serious health risk potential and can easily transmit disease to humans. Professionals should be called to ensure an entire mouse infestation has been removed.

Why do mice chew wires?

Mice are always looking for things to chew on. They are not very particular about what they chew, either. This is why they chew on wood and other substances. Because their teeth are constantly growing, they have to chew and gnaw on things to make sure their teeth do not grow too big and become fatal to the mouse. Mice also chew on softer things and what they chew on with wiring is not necessarily the wire themselves, but the rubber insulation around the wires.

Mice can create serious fire hazards by exposing wires which have been covered with insulation. What this does is create a hazard where wires close to each other can create electrical arcs or short circuits. This can easily spark a fire within walls where the dry wood or the materials the mice have collected to build their nearby nests can ignite.

Since mice prefer to be within the walls, the wiring they chew on tends to be hidden behind drywall and is hard to spot. Fires which start there are also often hard to spot until they have spread throughout the home or building and it can be deadly.

Mouse control and prevention

How do you get rid of mice? How do you trap mice? How do mice avoid traps?

The best way to get rid of mice is to call in a professional, like the ones we have at Ehrlich Pest Control, to ensure the entire infestation has been removed. This is because removing mice is difficult and just missing a couple of the rodents can create a new infestation.

There are numerous traps and poisons on the market which can be used to get rid of mice. However, there are risks to your family and pets because they will need to be put in places where children and pets can end up either injured from the traps or ingesting the poison. There are also a number of supposed DIY options for mice, but research has shown most of them either do not work at all or in such limited capacity we cannot guarantee they will get rid of the entire mouse infestation.

There are a couple of different types of mouse traps. The first and most common is the snap trap. These are the typical mouse traps you probably think of. They have a wooden base and a spot for some kind of food or bait to be placed. A metal bar snaps shut when the mouse consumes the bait and the trap breaks their neck or back, causing death. There is a risk of these traps snapping shut while being set and are strong enough to break fingers.

Another trap is the glue trap. These are small boards with a sticky substance and a bait set in the middle. Set at floor level and against walls, the mice will run into them and get stuck. This may not kill them instantly and requires clean-up from the homeowner which can be messy.

There are also poisons and poison traps, but the kind available to homeowners pose risks of contaminating others and can get on the homeowner’s hands unless precautions are taken.

Mice are also infamous for being smart enough to avoid traps. They have been shown to sneak bait off of the snap traps and can avoid the glue traps. This is why a mouse infestation can require multiple treatments and varying treatments to get rid of a full infestation.

The best way to really ensure you get rid of mice is to prevent mice from coming into your home or building at all.

How do you prevent mice in the house? How do you keep mice away? What repels mice?

The best way to make sure you do not get mice is to start off inspecting your property. This must be done for both homes and businesses and has to be as thorough as possible. Doing so can be challenging for the average homeowner, but even a tiny hole in the siding, no bigger than the width of a pencil, can provide access to the home.

Some of the things homeowners can do include:

• Seal up cracks and holes – if you have vents leading outside, holes in the roof, holes from cable television or electrical wires, holes in siding due to damage, it all has to be sealed up. Door sweeps should be installed for garage doors and any exterior door and, if possible, include steel fibers that mice cannot chew through. Make sure screens to patios and near exterior doors are sealed up and holes repaired.

• Keep tall grass and vegetation in check – mice will easily set up their nests in tall grass near homes. This is why having an empty lot next to your home with unkempt grass and vegetation can create a mouse infestation in your own home. Since mice breed fast, they quickly outgrow tall grass areas and will seek new areas to build their nests. Living next door to open fields that are overgrown can also lead to mice. Trimming back plants and vegetation from your home is important. Any tall grass or vegetation next to your home or business can give them easy access to the building.

• Remove piles of wood and hiding places from yards – mice will hide just about anywhere. If you have overgrown areas around your yard, or debris, garbage, woodpiles near your home and within your yard, you are creating hiding places for mice. This can quickly lead to mice finding a way into your home.

As for options that the internet tells you will repel mice, there is no hard data showing any of them work. Mothballs, fabric softener sheets, peppermint, and other substances have all been claimed by some to be effective DIY methods of keeping mice away. Ehrlich Pest Control cannot guarantee any of these methods will work and even if they appear to work at first, may not continue to work permanently.

Ehrlich Pest Control specialists are familiar with mice, the various species of mice, and how they get inside your home or business. Our technicians can spot the reasons mice are getting inside and offer solutions to stop them from doing so. Also, our rodent exterminators can offer solutions to get rid of the mouse infestation currently on your property and then prevent a return.

If you have spotted mice, make sure to contact your local Ehrlich Pest Control office and set up a property inspection and discuss treatment methods.

Alternatively, if you think you have a rat issue, please see our rat control page for more information.