Mice or Rats: How Do You Tell Which One You Have?

Short answer: Look at the droppings and where you hear the noise. Mouse droppings are about the size of a grain of rice. Rat droppings are bigger, closer to half an inch or more. Mice leave small, scattered signs, and rats often turn up in attics or near the ground outside.

You hear something in the wall at night. Is it a mouse or a rat? It matters, because the two behave differently and the fix is not exactly the same. Here is how to tell without having to see the animal.

Start with the droppings

This is the most reliable clue. Mouse droppings are small, around a quarter inch, dark, and shaped like a grain of rice with pointed ends. You tend to find a lot of them, scattered. Rat droppings are noticeably larger, about half an inch or more, and often found in smaller groups. Lay a coin next to what you find and take a photo. That one photo helps a lot.

Listen to where it is coming from

Mice are light and quick. You might hear fast scratching in a wall or ceiling. Rats are heavier, and a rat in the attic sounds more like something running or thumping across the ceiling. Roof rats climb well and love attics and upper areas. Norway rats are diggers and tend to stay low, near foundations, crawlspaces, and basements.

Other clues

• Gnaw marks: rats leave bigger, rougher marks on wood, wiring, and plastic
• Grease marks: dark smudges along baseboards and pipes where they run the same path
• Burrows: holes about the size of a golf ball or bigger along the foundation or under a slab can mean rats
• Nests: shredded paper, insulation, or fabric in hidden spots, from either one
• Size of the entry hole: a rat needs a bigger gap than a mouse does

Why it matters

A rat needs a larger opening, so sealing for a mouse alone may leave a door open. Rats also tend to be more cautious about new objects, which changes how traps and bait have to be placed. And whether the activity is up high or low tells a technician where to look first. None of this is a reason to guess on your own. If you are seeing droppings or hearing noises, a quick inspection pays off.

For the earlier clues, read the signs of a rodent problem. And our rodent control starts by finding exactly where they are getting in.

Hearing something in the walls?

Send us a photo of what you found and we will tell you what it likely is. Call or text us at (205) 855-7975.

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How can I tell mouse droppings from rat droppings?

Mouse droppings are about a quarter inch, like a grain of rice. Rat droppings are larger, around half an inch or more.

Do rats live in attics?

Roof rats do. They climb well and often nest in attics and upper areas, while Norway rats usually stay low near foundations and crawlspaces.

Why does it matter if it is a mouse or a rat?

Rats need larger entry gaps and act differently around traps, so the sealing and treatment plan is not exactly the same.