How Do Rats Get in My House?

Rat using window to get into house

Whether you have a rat infestation or you’re trying to prevent one, it’s important to know how rats get in the house in the first place. From cracks in the foundation to holes in the roof, rats don’t discriminate as long as they can find shelter, food, and water.


How do rats get in your house?

Don’t let a rat problem stop you from relaxing in your own home. Learn more about popular entry points for these pesky pests in order to keep them out! Rats get into your house…

1. Through cracks in the walls and foundation

Rats can squeeze through spaces that are as small as a quarter! That’s why it’s important to repair any damage in the foundation and walls in your house.

2. By sneaking into chimneys

When it starts to get cold, rats tend to sneak into homes through the chimney in search of warmth and shelter. If rats are entering through your chimney, try installing a mesh-covered chimney cap to keep small rodents from getting in.

3. Crawling in through roof damage

If you have rats in your attic, there’s a good chance you have holes in your roof. Make sure you have any damages in your roof repaired ASAP!

4. Through vents

Vents commonly have openings that are large enough for a rat to get through; rats can also squeeze through any gaps around the vent. To prevent rats from sneaking into your home through vents, seal any gaps and holes right away.

5. Entering through gaps around windows

Rats have no problems entering through gaps or cracks around windows. Solve this problem by sealing any openings and checking your screens for damages.


The best way to keep rats out of your home is by getting in touch with Griffin Pest Solutions! Our expert team can get and keep rodents out so you can spend time in your home worry-free. Contact our pest control experts today to keep pesky pests out of your space… no ifs, ants, or bugs!

How Long Do Rats Live?

Pet rats can live for four years, but a rat in the wild generally only survives between 1 to 3, and many won’t make it past their first. Overall rat longevity varies by species and is highly affected by the availability of food and water and the prevalence of predators.

Rats are social creatures and prodigious breeders. Even if they live out a fast and hard life, they can leave behind a legacy of several litters. Understanding and interrupting the life cycle of invasive rats can help keep them from becoming a larger problem in your home or business. Here’s what you should know:

Rat Life Cycle

Rats come into the world blind, hairless and helpless, but they don’t stay that way for long. Litters average from 6 to 10 pups who adapt and mature quickly. The pup’s eyes open after 12 days and within three weeks they will be fully grown and weaned. This means a whole batch of young, eager and hungry rats set loose on the world in a very short time.

Rats reach sexual maturity after three months and will breed for about a year. The gestation period for a pregnant female is 21 days, then the cycle begins all over.

On average, a female rat will be able to produce five litters during her lifetime. Multiply that by ten pups/litter and you quickly realize that a single rat can be responsible for 50 new rats within the span of a year. This doesn’t take into account the offspring those new rats will produce once they reach their sexual maturity in three months, either. Any way you slice it, that’s a whole lot of rats.

Life of an Adult Rat

Adult rats spend most of their life foraging and mating. This makes them formidable pests. They are nocturnal animals who seek new food sources by night. Their heightened sense of smell and ability to squeeze into small areas has allowed them to integrate all too comfortably in urban areas where they eat nearly anything.

Rats are social animals who live and travel in packs. This means if you see signs of one rat, you’re probably seeing signs of many rats. Packs are formed when a male and female pair branch off into an uninhabited space. It doesn’t take long for more rats to appear on the scene after they nest. Male rats move on to new partners quickly after they’ve mated and don’t contribute to the upbringing of newborns (bunch of deadbeats).

Though rats can live up to three years in the wild, the University of Michigan estimates that 91% to 97% of wild rats die after one year. The most common causes of death are predators, disease and harsh conditions. Adult males are especially susceptible to cancer and kidney disease.

How Can I Tell If I Have Rats?

The two most common types of rats in Michigan are the Norway rat or brown rat and the Roof rat or black rat. They are noisy and messy invaders. Signs that there may be rats living near you include:

  • Feces. Rats can produce up to 40 dark rice shaped droppings in a night. Look for them in basements and crawl spaces, especially along walls and corners.
  • Oily rub marks and smudges. Rats have very poor eyesight and establish regular travel routes via touch to move around spaces safely. As they utilize these routes, the dirt and grease from their bodies eventually leave marks along surfaces as they rub up against. Check for these marks along walls in your basement.
  • Bite marks. Rats need to constantly chew to keep their teeth from overgrowing. They’ll constantly gnaw on walls, floorboards, mesh, wiring… and pretty much anything else that’s soft enough to get a purchase on. This behavior is actually what makes rats dangerous, as they can start electrical fires if they chew through wiring until it sparks.
  • Scratching and squeaking sounds. Rats climb and chew within walls. Their teeth make a grinding sound, and they squeak to communicate among themselves. Rats tend to hide in the day and resume activity at night, so you’ll probably hear them late.
  • Nests. Rats build nests in lofts, attics or basements using foraged materials like insulation or cardboard. Check for these nests in secluded, cramped, and hidden places like beneath workbenches or shelving, corners, or even in ventilation systems

If you observe any of these signs, it’s time for a plan to remove the infestation before your rat population grows. Rats and mice in your home pose many risks.

How Do I Keep Rats from Living in My Home?

Rats are dirty animals that carry worms, ticks and diseases. They contaminate any food source they get into. Keeping rats out of your home or business means sealing your perimeter against invasion and preventing access to food sources. Here are a few preventive steps you can take:

  • Seal cracks and holes in your home’s exterior.
  • Cover chimneys, vents, and fans with mesh.
  • Seal windows and door frames.
  • Repair broken screens.
  • Secure trash and compost.
  • Clear leaf and brush piles in your yard.

Rats have an amplified olfactory system that can detect food smells through walls. They are very agile and can climb onto roofs and slip under doors and into cracks ¼” wide. Don’t underestimate a determined rat’s ability to breach your perimeter.


Hopefully with the right combination of rat control and prevention, you can reduce the average lifespan of rats in your home or business to zero. If you have rats inside already, it may be time to call in the professionals.

Call or contact us for a trained pest control technician to handle the dirty job of removing rats from your property and keeping them from coming back.

What Do Rats Eat?

Rats are not picky eaters, but they are smart. In the wild they eat fruits, nuts, grains, and insects. In urban settings, they’ll chow down on human food, pet food, and garbage, and spend their time hoarding as much food as they can while constantly seeking out new sources.

Though rats have near-unlimited appetites, they’re ironically careful around new foods. Because they lack the muscle structure to vomit, they’ll sample small amounts of new foods to be sure they won’t experience nausea after eating them. This means curious rats in your home or business will want to sample as much as possible before digging into your pantry. Here’s what you should know about what the rats around your home will want to eat, and how you can keep them from getting it.

What Can Rats Eat?

Rats are omnivores, meaning they eat both plant and animal-based foods. The type of foods they prefer can depend on the species of rat. The two most common rats in Michigan are the Norway Rat and the Black Rat.

The larger Norway rats prefer foods high in fat, protein, and sugar content. The smaller black rats (sometimes called roof rats) tend to be more interested in fruits and nuts. In the wild, both species are opportunistic and will eat fallen fruit, insects, and rotting animals.

If you are creating a bait station to trap rats, foods like bacon, peanut butter, chocolate, and dried fruit tend to work best. It’s important to bait the area around the trap and not just the trap. Rats are careful animals and will sample the food, let it gestate, and return to the source if they liked it.

What Can’t Rats Eat?

There are a few foods that rats don’t like or are toxic to them. These include:

  • Citrus fruits
  • Green bananas
  • Green potatoes
  • Rhubarb
  • Blue Cheese

Male rats are especially vulnerable to these and can experience kidney failure as a result.

Rats may not digest the wood, plaster, or electrical wiring in your home, but they certainly will chew on it. Rat’s teeth are constantly growing, sometimes 4 to 5 inches per year. This means that rats need to continually gnaw at whatever is on-hand to keep their bothersome biters from getting too long. In fact, rats gnaw so constantly that the bite marks they leave behind are one of the telltale signs of infestation. The worse your rat problem, the more evidence of gnawing damage you’ll find over time. Rats will even gnaw on electrical cables, which can make this behavior quite dangerous!

How Do Rats Find Food?

Rats are nocturnal scavengers who forage under cover of night and social creatures that travel in tight family packs.

Rats locate food through their exceptional sense of smell. They are genetically wired to pick up different smells via their olfactory epithelium. They also have a secondary organ that specializes in pheromone and chemical smells called the vomeronasal organ (VNO). The VNO is key to their communication, courtship, and parenting. The net result is that rats have a very sensitive sense of smell that allows them to locate food sources quickly. Their heightened pheromone sensitivity and smell senses mean they can even tell other rats what food is available and where to find it.

Rats outside your home or business can smell foods inside very easily through tiny cracks or even walls. Once they smell it, rats are very adept at literally following their noses to tiny access points where they can sneak inside.

How Do I Keep Rats Out of My Food?

Rat crawling through a crack to get into a house

Rats are unhealthy creatures that you don’t want in your home, let alone your food. According to the centers for disease control, rats and mice spread over 35 types of disease through their urine, feces, saliva, and bites.

An adult rat can crawl under a door or through a crack ¼” wide. Keeping rats out of your home or business means keeping all potential entrances sealed. This is especially important in late summer and fall when they seek new food sources and nesting grounds.

Keep rats out of your space by:

  • Sealing all cracks in your foundation and siding.
  • Weather stripping around doors and windows.
  • Moving firewood at least 20 feet from your home.
  • Trimming tree branches near your home.
  • Securing trash and compost.

A certified pest control technician can assess your property, point out high risk areas, and even do the work to secure you against rat infestation.

What Do I Do if I have Rats?

Killing rats is a tricky job. There are many different over-the-counter traps and poisons you can try, but rats are cunning and good at evading them. Disposing of dead rats isn’t a fun job either.

If you’re in Michigan and want guidance at any level, call or contact Griffin Pest Solutions today. Our certified staff are rat control experts. We can eliminate on-site invaders and rat-proof your home or business against future infestations to be certain your would-be rodent restaurant stays closed for good.

The Late Summer Rat Problem

Outside rats move inside when temperatures fall

We don’t like it any more than you do, but it’s time to face facts: summer is ending. Fall will be here before we know it, whether we’re ready or not. If you pay attention, you’ll notice the whole world preparing. Squirrels are busy gathering food, ants are reproducing, and bees are swarming.

Unfortunately, some of these fall preparations might be a problem for you. Rodents like mice and rats are gearing up for fall and winter like everything else. The first item on any rat’s fall preparation list is finding a warm place to stay. If you’re not careful, that place could be your home. The only way to keep rats out this late summer is to beat them at their own preparation game. Here’s what those rascally rodents are up to and how to counter them at every turn:

Looking for Food

Rodents have an incredibly keen sense of smell. Rats can interpret all kinds of information from different scents. This sense of smell helps guide rodents toward accessible food supplies. Rats can smell food through walls, even if it’s dry and stored. They can even smell how easily they’ll be able to access it. Rats literally follow their noses to sources of food, letting scents guide them to vulnerable access points.

Rats are looking for consistent sources of food they can access easily. They want to be able to sneak into boxes of food to chow down without anyone noticing. Make that as hard as possible. Store all your dry goods in airtight plastic containers. Clean up your dining and kitchen areas after every meal. Take your garbage out every night. If you can make your food hard for rats to get at, they’ll be much less interested in trying.

Rats start building nests in late summer and fall

Building Nests

Rodents aren’t picky about nesting material. They build small, tightly-packed clumps of various debris, which they rest and eat in. Rats build their nests of paper, insulation, stray fabric, and other trash. They gather these materials by dragging them into dark corners. Often, rats will rip paper or other objects to shreds to use as nesting material. Rodents also rear their young inside these nests, where they can stay safe and hidden.

Rats build their nests in dark, secluded, and warm areas. They want to be able to rest and forage for food without fear of being spotted. Consequently, if there’s a rat nest in your home, it’s probably in your basement, attic, or crawl space. Look for nests in corners or beneath furniture. Rats often build nests into damaged insulation, walls, or other nooks and crannies. Prevent rats from building nests by taking care to keep your basement clean and tidy.


Rat and mouse teeth never stop growing, so the rodents never stop teething. Rats and mice have to gnaw on something constantly to keep their teeth sharp and healthy. They’re not particularly picky about what they chew on. As long as it’s soft enough to bite down on safely, rats are all over it. Teething is a big reason why rats can be dangerous inside homes. When rats bite down on wiring, they could start dangerous electrical fires.

Rats gnaw on soft materials that they can access while they’re sneaking around. Usually, they’re chewing on boxes, storage materials, fabrics, or wiring. The best way to keep rats from damaging your stuff by chewing on it is to elevate it. Keep vulnerable stored materials in an elevated place where rats can’t reach it. Replace your cardboard boxes with hard plastic ones. Conceal and protect electrical wiring whenever possible, and consider affixing it to the wall.

Rats sneak into homes to find shelter in late summer and fall

Looking for Shelter

Rats have extremely keen perceptive senses developed over centuries of hard-won survival. One of the main reasons why they have these developed senses is so they can prepare for environmental changes early. When they start sensing a season’s change, they start looking for warm shelter right away. Rats use several senses to start searching for shelter. Their whiskers help them locate drafts and warm breezes, which they can follow into structures.

Rats use their heightened senses to find all kinds of access points. Once they find these access points, they can twist and squeeze their way in through surprisingly tiny openings. Rodents frequently squeeze through openings in door and window frames, utility lines, and small foundation cracks. Many rodents can climb surprisingly well to access openings, but most get in via access points close to the ground. Finding and blocking off these access points is the most important thing you can do to prevent rodent infestations.

Rodents are very, very good at preparing for cold weather. One of their most dastardly techniques is sneaking their way inside before we know to look for them. If they’re safely ensconced in your home before the temperatures even drop, they won’t have to worry about your fall defenses!

If rodents start this early, we have to start preventing them this year, too. Follow these tips starting now to keep rodents from infesting your home this fall. It’s not too early to start thinking about winter! If you do end up with rodents now or later, however, remember that you can always give Griffin a call. No matter how prepared your rodents are, we’ll prove we’re even more prepared.

How to Have a Rodent-free New Year

If you’ve ever had a rodent in your home, you know how persistent they can be. You lay out traps, seal off cracks, and even call in pros, but year after year, there they are. It’s easy to get discouraged or even apathetic about the whole process. But not this year. This year things are going to go differently. This year you stop the rodents. We’re here to help.

Sound ambitious? It’s easier than you think! Just follow these four steps, and you’ll be well on your way to creating a rodent-proof environment. Don’t give up! Getting a jump start on this will give you the momentum you need to complete your other resolutions. It all starts here!  

Replace Weatherstripping

replace weatherstripping to keep pests outWeatherstripping is the long, rubber material that makes up the threshold between doors and windows and their frames. This stripping makes an airtight seal between the door or window and the outside air. Without it, outdoor air would slip through the cracks and enter your home. Over time, weatherstripping can wear down. Damaged weatherstripping may not keep outdoor air out, or it may peel away from the threshold all together. Either way, it provides a perfect opportunity for rats and mice.

When outdoor air seeps in, the pressure difference between that air and indoor air creates a vacuum that sucks heat out. Rodents outside feel this heat escaping and follow it to its source: the damaged weatherstripping. Rats and mice can easily bite through or sneak under weatherstripping that’s already been damaged. Examine all the weatherstripping in your house and replace any that looks worn. You can buy inexpensive weatherstripping materials at most hardware stores.

Seal Utility Lines

Seal utility lines to keep pests outMice only need an opening the size of a dime to wriggle their way into your home. Some of the most common openings they find are around your utility lines. Gas, water, and electrical appliances have pipes, vents, and cords that need to enter your home from the outside. Rodents often follow the smell of gas or water along a pipe. Eventually, they’ll reach the opening where that pipe enters the home.

Cutting off this avenue of infiltration is simple. First, walk the perimeter of your home looking for any utility line access points. When you find them, check to see if there’s an opening rodents could use to enter your home. Remember: it can be a small opening. Use caulk or steel wool to seal this opening as snuggly as you can from the outside. To be doubly sure, go inside and repeat the same process. Utility lines are the #2 way rodents get into homes after windows, so don’t neglect this simple chore.

Clean Yard

Keep the lawn clean to keep pests outBefore rodents are attracted to your home, they’re attracted to your yard. All kinds of things bring them there: food, moisture, shelter, even random debris. Food can mean various things in this context. It could be pet treats, vegetables, fruits, or even bird seed. Moisture could come from bird baths and water features, or from sinkholes and puddles. Shelter is anything they can hide in or under to get away from predators. Random debris can be used for nesting or cover.

Keep your lawn mowed short, and prevent weeds from growing in it. If you have a garden, fence it off and protect it from pests. Be careful not to overwater your plants or grass, and don’t let water sit for hours. Keep your yard uncluttered and clear by picking up fallen seeds, branches, leaves, or fruits. Trim hedges and brush to a short, uniform length. It’s less obvious than the other tips, but yard care is an important way to keep rodents out.

Take Out the Trash

Take out the trash frequently to keep pests outRats and mice have truly incredible noses. Not only can they smell much better than we can, they can discern specific information based on smells. Information like where food is, how much there is, and how easy it would be to take. While rodents may come around looking for shelter, they’re probably interested in your home specifically because of food. Nothing attracts pests, including rats and mice, quite like the pungent aroma of garbage. It’s like an all-you-can-eat buffet.

This is another anti-pest tip that’s surprisingly easy to implement. First: line all your garbage and recycling cans with plastic bags. Make sure all the garbage you put in your cans actually ends up in these bags. Next, take the bags out of the cans and to the outdoor dumpster every night before bed. Seal the bags tightly before you throw them out. Keeping your garbage outdoors and away from your home will remove the main thing attracting pests to your home.


If these tips sound simple, it’s because they are. If they sound too good to be true, just give them a try! Even if you don’t solve your rodent problem overnight, you’ll be on the right track to a rodent-free new year.

If you need some help making that final push and driving the last of the rodents out of your home, just give Griffin a call. Our rodent experts have been fighting the furry menace since 1929, and they haven’t beat us yet. Have a great, pest-free new year!

The Season of the Rodent

Rats and mice are very active this time of year.

Autumn can be one of the nicest times of the year. The leaves change color. The temperature is perfect. Even the sky just looks bluer. Everyone knows Winter is Coming, but at least fall makes for a nice consolation. At least, it should. Unfortunately, “everyone” knows Winter is Coming. Everyone includes rodents.

When the temperature drops, rodents start trying to get into your place like their lives depend on it. Nothing ruins the last nice weeks we have left like a rat infestation. You should be enjoying the all-too-fleeting pleasures of autumn while you can–not stressing out about the rats in your basement. Here are four good ways you can ensure unwelcome guests stay out of your home this fall.

Seal Doors and Windows

seal doors and windows this fall to keep rodents outMost of the heat that escapes from homes leaks out of gaps around door and window frames. Rodents can feel this warm air escaping from outside, and they can follow it back to its source. Mice and rats are notorious for their ability to squeeze through tiny gaps. Even a tiny crack in a window frame’s weather-sealing is more than enough space for a motivated rodent.  

Double-check every window in your home. Make sure the window pane sits properly and the weather-proofing hasn’t worn down or peeled away. Look for cracks or other damage in the frame itself, as well. Check for condensation on the window sill and run your hand along the frame to feel for cool air. If you find either, it means there’s probably a draft around the window. Find and seal up this draft, and you’ll go a long way toward keeping rodents out of your home. Once you’re finished with the windows, follow these same steps at each outside door.

Put Screens over Vents

put screens over your vents this fall to keep rodents outYour home transfers outdoor air in and out from more places than you’d think. Pretty much every water-using appliance needs to have a ventilation system to function properly and prevent excess humidity. Vents work by transferring hot air out of your home. Unfortunately, rodents can feel this hot air from outside just like they can feel drafts. If your vent systems aren’t appropriately covered, then rats can use them to crawl into your home.

Remember: you need to leave enough space in your vent system to let air pass through. If you don’t, you’re defeating the purpose of having ventilation in the first place. Putting screens over your vent’s outlets will allow air to flow normally while keeping rodents out. Remember, however: rats and mice are notorious gnawers. Check on your screens annually to make sure the annoying munchers haven’t chewed their way through. If any of your screens have been noticeably damaged, you should replace them as soon as possible.

Check Outside

clean up your yard this fall to keep rodents outWhile you’re out checking your vent covers, take a look around the foundation of your home. Look for cracks where you can see light from inside, or where you can feel heat escaping. Pay special attention to areas of the home where utilities like water and gas enter the building. These access points tend to have gaps juuust wide enough for rodents to enter.   

After you’ve “secured the perimeter,” you could take this opportunity to de-clutter your lawn. Fall tends to drop all kinds of debris into your yard. Rodents use fallen leaves, overgrown bushes, weeds, and other clutter as a means to get close. Keep clutter like leaf piles or firewood at least five inches away from your home. Keep trimming your bushes and lawn until they stop growing for the season. Make sure tree branches don’t brush up against your home. This all might sound extreme, but rodents really will use anything they can.

Clear the Clutter

clean up your basement this fall to keep rodents outYou didn’t think you’d get away with only cleaning the outdoors, did you? Sorry, but once you’re finished de-cluttering your yard, it’s time to move inside. Messy basements and attics attract rodents looking for warm, dark, and hidden places. The more space they have to move around in secret, the more attractive your home will look to them. One of the best ways to make sure rats leave you alone is just to demonstrate that you know they’re there.

First, pick up boxes and bags lying on the floor in your basement. Sort through them, organize them, and keep them on shelves or in cupboards. Keep your floor as clutter-free as possible to make rodents feel uncomfortable crossing it. Vacuum and dust every room in your home at least once every two to three weeks. You should vacuum any rooms where you eat or prepare food even more frequently. If you can deprive rodents access to the resources they came looking for, they’ll start looking elsewhere for them.


The stakes never get higher than they are right now. Rodents that get into your home during warmer months come and go as they please. If rodents get into your home in fall, however, they’re staying for the duration. Winter is hard enough without sharing your space with furry roommates.

Even if you do end up with rats this winter, though, you don’t have to despair. Griffin Pest Solutions isn’t flying south; we’ll be here all year to help you with any pest problems you have. We’ll keep pests out so you can get back to enjoying one of the most beautiful times of the year.