Pest Information The Differences Between a Rat and a Mouse, and Why You Need to Know

The Differences Between a Rat and a Mouse, and Why You Need to Know

It’s easy to mistake rats and mice for eachother, because you often only see a fleeting glimpse as they scurry to hide. But knowing the difference between them is important if you need to get rid of them from your home. Learn how to tell them apart from their looks, behavior, droppings, and signs they leave around your home.

If you hear the pitter-patter of tiny feet in your home — and it’s not your kids — you might have a rodent problem. But, if you’re not much of a zoologist, how can you tell who the culprits are?

You may not think it matters whether it’s rats or mice, but the approach to extermination and exclusion will be slightly different. It’s important to know which creature you have in your home for effective, permanent removal.

We often only catch fleeting glimpses of invasive species in our home. Let’s face it; they haven’t made a successful living out of being where they aren’t wanted without learning a few things about stealth!

Once you know what to look for, though, it’s not so difficult to make the call: Mouse or rat?

So today, we’re going to teach you the fundamental differences in appearance and behaviors of mice and rats. Plus, we’ll help you solve the mystery without even laying eyes on the trespassers by identifying the tell-tale signs each type leaves behind.

Please keep reading for our rodent round-up!

What Does a House Rat Look Like?

Side view two brown house rats sitting on a wooden table

As with mice, there are many species of rats in the world, and they have made themselves at home virtually everywhere. They are intelligent, adaptable, and thrive in urban conditions that drive other mammals away. And just like mice, wild rats are quite different to their domesticated fancy pet rat cousins.

Most rat infestations involve either Norway rats (sometimes known as the sewer rat or brown rat) or roof rats (aka the black rats).

The Norway rat is pretty hefty, with a large body, thick neck, and large head. The body alone may be up to 10 inches, already larger than a mouse. Add in the tail, and your beast could be a

foot-and-a-half long (18 inches).

Roof rats are a bit smaller, topping out at 9 inches, including the tail, with a more slender body. Unless you live near the coast and somewhere reasonably warm, you’re unlikely to have roof rats.

Here’s the problem, though, with identifying by sight — a juvenile rat is about the same size as an adult mouse.

Points of difference include:

  • Tails, which on rats are shorter than the body, thick, and hairless, and may appear scaly
  • Ears look proportionately smaller than on mice
  • Snouts are typically blunter

Animals Commonly Mistaken for Rats

A grey, american squirrel sitting looking into the camera
Easy to tell apart from a rat when you can see their tail, not so easy at first glance from other angles.

Do rats have any look-alikes? One comes to mind…


This is another rodent species that has done well making a life for itself in the city. If there’s enough green space, like urban parks, squirrels will thrive. They may also decide to choose your attic for a home.

Fortunately, their fluffy tails and “friendly” faces (large eyes, chubby cheeks) make them easy to tell from rats if you get a long enough look. Squirrels will rarely use your home for anything other than lodging and are seldom found in kitchens and pantries, unless you left the door wide open.

What Does a House Mouse Look Like?

A house mouse sitting on some grey bricks

There are many species of mice, and they’re found in nearly every country on the planet. Within your area, you may have both native and invasive species of mice; the famous house mouse found all over Europe and North America, likely came originally from somewhere near Iran.

Fortunately, almost all mice look very similar. You can tell one species from another by its colour and other characteristics, but that’s a level of detail we don’t need.

In basic terms, a mouse is a small rodent typically ranging from 2.5 – 4 inches in length, not including the tail. Adding the tail typically doubles the animal’s length, and it’s usually quite thin with only a light coat of hair.

Fancy pet mice may have interesting color patterns, but the types you’ll find in your home are almost always brown or gray. Why? Because mice hide for safety, and a flashy coat is a dead give-away.

Looking at the head, mice have long, triangular snouts and noses, with long whiskers to feel their way around and sense the environment. Their ears may look disproportionately large for the small head, and their eyes define “beady”; they’re little, dark, shiny, and protruding.

Animals Commonly Mistaken for Mice

Two photos, one each of a vole and a mole, both on grass and mud
On the left a vole, on the right a mole. Both are often mistaken for mice.

Not every small furry thing is a mouse. Here are some of the animals most commonly misidentified as mice.


These tiny, burrowing mammals are nearly identical in size and color as mice. However, they’re usually a bit chunkier, with shorter snouts and tails. They have smaller ears, too, which may be difficult to spot. Voles seldom come indoors, since they prefer eating your garden vegetables and plants.


Again, some species are very similar in color and size to mice. The most obvious distinguishing characteristics are large claws for digging and tiny eyes — they’re so small, you might think they don’t have any. Moles are not often found indoors, but they can make a royal mess of your yard.

Where do Mice Live in a Home?

Mice are very small and can squeeze through tiny openings, including under doors. They’ll move in anywhere that seems cozy and secure on any floor from the attic to the basement.

Cardboard boxes that are seldom disturbed are ideal homes for mice, as are sheltered corners, voids between walls, and accessible drawers or cabinets.

They will most often choose to nest near reliable water sources and food, typically no more than 50 feet away, to minimize their exposure. Mice can be problematic in the home, as they can also carry fleas with them.

Where do Rats Live in a House?

Rats will access your home through air vents, large cracks in the foundation, or even through drain pipes — they are fabulous swimmers.

Roof rats, of course, prefer high-level access and love to set up camp in attics, walls, and above drop ceilings.

Norway, or brown rats, are burrowing animals and habitually sticking to the basement or ground floor, or may choose to nest just outside your home, perhaps under a porch or patio, and access your home for food raids.

How to Tell a Mouse Infestation from Rat Infestation

Here are some basic indicators of who’s causing you grief, mice or rats.


Rodents are stealthy by nature and may be very hard to spot. Their droppings, however, are plainly seen. Based on this unpleasant evidence, it’s usually possible to tell if you have mice or rats depending on which droppings you see in your home.

Mouse droppings are usually black and look like a burnt grain of rice. Depending on the mouse, they may be anywhere from about 1/10″ – 3/10″ long (3–8 mm). Mice tend to poop not far from the nest but will leave droppings scattered about just about anywhere. Lots of them, too; an average mouse leaves up to 100 pellets daily.

Brown rat droppings are wide, dark brown, are tapered at the ends and are up to 1/2″ long. Black rat droppings are curved, long, thin, and pointy. Black rat poops are smaller than brown rats, but both are larger than mice droppings. You’ll find that rats leave fewer “souvenirs” for you than mice, about half as many per day.

Because they are so different, being able to identify brown rat droppings, black rat droppings or mouse droppings is a sure fire way to know precisely which pest you are dealing with.


Listen carefully. Do you hear footsteps in the ceiling or walls? If you answered “yes,” it’s probably rats. Mice are so small, they are often difficult to hear. Rats, however, are large enough to hear walking, running, or even chewing.

The main reasons rodents break into our homes are for food and shelter. You may be able to tell if it’s mice or rats based on what they’re eating and where.

All rats and mice eat cereal grains, such as wheat, rice, and oats. You might see that mice remove the husk and eat the insides, and rats chew them in half. Mind you, both species tend to take food back to their nest for storage, so you may not see evidence in the kitchen. Black rats also enjoy fruit, so if you have a fruit bowl out, you’ll want to remove it.

Brown rats will raid the same spot repeatedly, and mice will have a couple of preferred locations. Brown rats wisely mix it up, seldom returning to the same place two nights in a row.

Finishing Thoughts

By now, you should have a clearer picture of whether you have rats or mice in your home. Either way, you’ll want to take immediate action to get them out. Rodents can cause damage to homes and may also be a health hazard. And, it’s just plain unsettling to know they’re there.

For more on mouse and rat infestations, search the site for helpful information. This is a fixable problem, but it’s essential to do something ASAP, whether that’s dealing with it DIY, or calling in pest control experts.

Thanks for coming to us for help; together, we can handle the situation.

Managing Editor & CEO Jack has been writing as a contractor and for businesses for over 10 years. He owns his own home, and has been doing his own pest control since he bought his first house.

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