Mouse Vs. Rat - How to Tell The Difference

01.10.2006 - Rats and mice are similar in appearance. In fact, people often confuse juvenile rats for mice, and the two do look extremely similar. While there are several species of rats and mice, I will examine the two most common ones, the Roof or Black Rat, and the House Mouse, both seen in the above photograph. As you can see, the biggest difference is size. Rats grow to a body of 8 inches and a tail of 9 inches, and a weight of almost a pound. Mice rarely grow more than 3 inch body 3 inch tail, and a couple of ounces. Next is color, and rats tend to be gray with white bellies, turning more brown as they get older. Mice are more brown to begin with, and have darker bellies. Next is the tail. It's black with scaley rings on a rat, and tan and more smooth on a mouse. The feet of a rat are also longer in proportion to the body, and a rat's ears are also larger. But these variations are subtle. The primary thing, of course, is the size difference. Mice are really small!

Their behavior is also similar of course, very similar, and once again, the differences are subtle. The main difference is that mice are bolder. They will investigate new things, explore their environment, and blunder right into traps. Rats are a bit craftier, dodgier, and much more cautious. Rats live their lives in fear. They are wary of investigating new things, and they don't explore much. In that sense, people believe that they are harder to trap, but I've never had any problem trapping rats.

I caught both the above rat and mouse today in Orlando. Not in the same place, mind you, although they probably share territory in some areas. Mice are actually very rare in central Florida. I caught this mouse at a lawyer's office in downtown Orlando. The attic has a mouse infestation that I will soon remedy. I've already sealed the building 100% airtight, so now it's just a matter of catching the rodents stuck inside. Same as my method for solving a rat problem. The primary difference for me between these two critters? Different sized trap!

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Do it yourself: Visit my How To Get Rid of Mice page for tips and advice.
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CUSTOMER EMAIL: How can I tell the difference between a mouse and a young roof rat?

Hi, Short question, long story.

We definitely have roof rats – I saw one, in broad daylight, coming down the outside back corner of our stucco-sided garage (I guess they don't need overhanging trees to get to the roof after all) in southern California. It paused at about eye level and looked at me, like, “What are YOU doing here?” as I looked at it, loudly thinking, “What are YOU doing here?” then scampered off down to the ground and ran out towards the front fence of the yard. It was sleek and shiny-coated, warm black in color, and about 7 inches long, with a pointy nose and large ears.

Meanwhile, my husband has been seeing grey rodents out of the corner of his eye in the garage, running along the top plate towards holes leading into the attics (our attics have no access for humans, unfortunately). He also saw one outside behind our shed in the back of the property, where he has been storing a collection of clutter outside. When we first moved in about 6 months ago, we found a dead (desiccated) grey mouse in the garage in one of the built-in base cabinets near the front of the garage, about 2?-3” long. I also hand-watered the lawn one day and had a soggy light-grey mouse about 2 - 2?” long run over my foot to get out of the wetness and over to the trees along the back edge of the property. So we definitely have mice, too, so I wasn't sure whether my husband has been seeing mice or rats.

Before I cleared out all of the weeds under the trees along our back fence, I used to frequently hear animals running back and forth the length of the back fence. I still hear them every once in a while, but not as often. We have two orange trees, and one of them has a lot of fruit that have a one- to 1?-inch hole bitten into them and the insides completely hollowed out, most likely by rats. That tree is near the shed at the back of the property. And there are grease marks where rats have been climbing up another corner of the house, and both rat and mouse poop in various places. We also had a ground squirrel family with 5 babies that had a nest at the edge of our garden, but some chicken wire around the vegetables seems to have been adequate to protect them. It was fun to watch the babies grow up, expand their range, and eventually leave our yard.

For a couple of months, I've been hearing occasional scratching and scrabbling over the bedroom ceiling and the upstairs bathroom ceiling at about 7-8am, so we had to do something. I've also heard scrabbling above the ceiling in the kitchen, which means they are also in the walls/the space between first floor ceiling and second floor flooring. We had a pest control company out that does do rodent exclusion, and they did a couple of weeks of snap-trapping prior to the exclusion work, but I've been checking and re-baiting the traps in between their visits. We've caught two rodents in the rat traps, one along the garage top plate near an attic entrance, and one behind the AC compressor on the patio behind the garage near the man door. As mentioned, our attics don't have any access to them, so no inspection or trapping was done inside the attics, but several entry points in roof transitions and in the garage were identified, as well as the rub marks on the side of the house. Three bait stations of detex blox along the back fence were completely emptied in a week, with the pins holding the blocks in place were removed as well, so it's like they're hauling the entire blocks out.

I still have a question as to whether the two rodents we've caught were rats or mice, though. They seemed a bit large for mice (3? - 4” long), but grey, not black. The one on the top-plate was caught by its tail in two places and still alive (the whole thing came crashing down to the floor), and I asphyxiated it to kill it by scooping it up, trap and all, into a sealable glass food container and closing the lid. It took several hours to die, which I wasn't thrilled about, and my husband even less so. The one behind the AC compressor had its thoracic spine snapped in two and probably died pretty quickly.

The pest control guy (who has been to a couple of courses on rodent control) took a look at the more recent capture and says it's a juvenile rat, not a mouse. But I wanted to know how I can tell for sure. Roof rats and mice both have pointy noses and larger ears, compared to Norway rats. Are juvenile roof rats lighter in color than adults? The pest control guy said that a mouse would not have been heavy enough to spring the rat traps. He used the Victor Easy Set rat traps, same as the ones you recommend.

Today they closed up the identified entry points (except for one, to let any more juveniles that might be inside, out, right into a trap behind the washer and dryer), as well as one more small one that he found on the roof today. They'll be back again in a couple of weeks for a final visit to close up the remaining entry. The bait stations are still in the back, but empty – I did not sign up for them to bait and monitor them. And the snap traps that were on the roof have been relocated to other places where we have seen evidence of activity on the perimeter of the house.

I just found another vent screen with a tear in it, so I guess I need to find the hardware cloth and repair that today, too. Sigh.

So, more than you needed to know to answer the question.

Thanks, Rebeccah

MY RESPONSE: Sounds like rats to me. Google search for photos to tell the difference. Regardless of whether it's mice or rats, the method of solving the problem is the exact same, but rats are a bit easier:
1 - Inspect the house and find out how the rodents are getting inside.
2 - Seal up every single last entry/exit hole and gap with steel.
3 - Trap, properly trap on rodent runways, ALL the rodents, and remove them from the house.
NEVER USE POISON. It causes more problems than it helps. If you've sealed the house properly, you never need poison anyway.
OPTIONAL - Clean up the attic space (vacuum droppings and spray Bac-Azap) or home once they are all gone for good.
HELP - If you need professional help from an experienced pro that I recommend, go to my directory

It's easy to group mice and rats together as they're both rodents, but they do have significant differences in appearance and habits. When it comes to the removal of rodents, it's important to tell the difference so you can adjust your strategy accordingly.

Similarities between Mice and Rats
First, let's get through what they both have in common. Both mice and rats can make a home out of your house, shed, or garage. Essentially, they seek warmth, safety, and food. Luckily for them, that's also what we seek in our homes.

Both mice and rats chew through wiring, walls, furniture, and contaminate food. They also leave droppings and fur grease on surfaces.

They're both nocturnal, so you can expect a lot of activity in your walls, floors, and ceilings at night.

Differences between Mice and Rats
Now that you know their similarities, it's time to get into what makes them different.

Appearance
Rats are huge, growing up to 19 inches in length with a long, scaly tail. In contrast, mice are only about 7 inches long with large ears. The fur of rats can be red, brown, grey, or black with lighter underbellies while mice are generally just grey or black.

Droppings
Rat droppings are shaped like pills about ¾ of an inch in size. Mice droppings are rice-shaped, meaning they narrow at one end, and are up to ¼ inch in size. Mice droppings are never found in piles, they're always scattered.

Sounds
Rats are aggressive rodents. They gnaw, scratch, and fight over food. They can also swim, which is unsettling, and climb their way to elevated places like roofs. Given their size, it would be impossible for a rat to be silent while splashing around or climbing up your walls.

Mice are quieter (and they don't swim). They squeal and make little scratching sounds. They are great jumpers, and you'll likely hear them sliding against the wall because they try to always maintain contact with it while in the dark.

Markings
Rats leave large, rough-edged holes on things they've chewed, like your drywall. They also enjoy gnawing on pipes, electrical wiring, and wooden beams. Mice, on the other hand, leave small, smooth holes on things like cardboard boxes and plants.

If you spot a rodent in your house, try your best to identify it before calling pest control. It'll be exponentially more helpful in getting rid of them.