Mice vs rats
A simple comparison of size, droppings, noises and entry gaps to help you tell mice from rats.
Mice and rats cause similar problems, but they are not the same animal, and they are not handled the same way. Here is how to work out which one you have before you decide what to do.
Quick comparison
| Mice | Rats | |
|---|---|---|
| Size | Small, fits in the palm of your hand | Much larger and heavier |
| Head and nose | Pointed nose, large ears | Blunt nose, smaller ears |
| Droppings | Small and pointed | Larger and blunter |
| Entry gap | A bit over 1/4 inch (about 6 mm) | A bit over 1/2 inch (about 13 mm) |
| Typical sounds | Light scratching | Heavier scratching or thumping |
| Common nest spots | Wall voids, cupboards, storage | Burrows outdoors, attics, wall voids |
The gap sizes come from University of Nebraska extension guidance.
Which is bigger, and how do they look?
Mice are small and slim, with a pointed nose, big ears and a long, thin tail. Rats are heavier, with a thicker body, a blunter nose, smaller ears and a thick tail.
Young rats can look like mice, so size alone is not always enough. Use several clues together. Our pages on mice and rats cover each in more detail.
How do droppings and gnaw marks differ?
Mouse droppings are small and pointed at the ends. Rat droppings are larger and blunter. Sources vary on exact measurements, so compare what you find against both descriptions rather than relying on a number.
Gnaw marks work the same way: smaller, finer marks suggest mice, and larger, rougher ones suggest rats. Both gnaw wood, wiring, plastic and packaging.
Wear rubber gloves and a dust mask when cleaning droppings. Health Canada says to dampen them first and never sweep or vacuum them dry.
What do they sound like, and where do they nest?
Light, quick scratching in walls often means mice. Heavier scratching or thumping, especially in attics or under floors, is more typical of rats.
Mice nest inside buildings, in wall voids, boxes, drawers and insulation. Rats may nest in burrows outside, under sheds, decks or concrete slabs, and also inside walls and attics.
How small a gap can they get through?
University of Nebraska extension guidance says mice need only a little more than a quarter inch, and rats a little more than half an inch. Gnawing can enlarge small cracks quickly.
Health Canada recommends metal weather stripping on doors, steel wool around pipes, and fine metal mesh over vents. These materials apply to both.
Which is more dangerous?
Health Canada says both can carry disease and damage property. It names the deer mouse as the most common carrier of hantavirus. Neither is a reason to panic, but both call for careful cleanup and prompt action.
Do they need different treatments?
Often, yes. Rat problems frequently involve the yard, bins and burrows, as well as the building. Mouse problems are more often about gaps indoors and food in the house. Because the plan depends on the animal, correct identification comes first.
Our four steps (inspect, identify, treat, follow-up) are explained in our integrated pest management guide. Our rodent control page covers both mice and rats.
Can I have both?
Yes, though it is uncommon. In a larger building, mice may be in one area and rats in another. An inspection confirms what is there.
Rules for owners and tenants
In Toronto, the City says residents and business owners are responsible for keeping their property free of conditions that attract rats. Tenants in apartments should first contact the landlord or property manager, then 311 if the problem is not dealt with. See our Toronto page for the area we serve.
Get a free quote
If you still can’t tell which you have, we can help. Request a free quote and quote details reach you within 30 minutes. You can also call on the number at the top of the page.
Common questions
Can a baby rat be mistaken for a mouse?
Yes. Young rats are small and can look like adult mice. The clues are the head and feet, which look large for the body on a young rat, and a thicker tail. Droppings and gaps help confirm.
Which causes more damage?
Both gnaw wiring, insulation and packaging. Rats are larger and stronger, so they can do more damage per animal. Mice often cause more trouble in total because they are so hard to see and spread widely.
Are rodents active in the daytime?
Mainly at night. Seeing one in daylight can mean there are many, or the nest has been disturbed. Either way, it is worth getting checked.
Do I have rats in the attic or mice?
Heavy thumping or gnawing at night suggests rats, and light scratching suggests mice. Droppings size and entry holes help. If you are unsure, an inspection can confirm which you have.
What smells point to rodents?
A musky, stale smell in closed spaces, such as cupboards, wall voids and attics, is a common sign. A strong smell can also come from other sources, so use it alongside droppings and noises.
Do cats keep them away?
Not reliably. A cat may catch the odd one, but mice and rats hide in walls and attics. Sealing entry points and removing food matter far more.
Get a free quote
Tell us what you found and where. We send quote details in under 30 minutes.