In Quebec, the deer mouse, a field and woodland mouse of the genus Peromyscus, is often called a "mulot" in French. It looks like the house mouse but doesn't carry the same risks. The Norway rat, on the other hand, is much bigger.
At a glance
- Deer mouse ("mulot"): brown or grey back, white belly and feet, hairy tail that's dark on top and white underneath.
- House mouse: body length of 6.5 to 9.5 cm, uniform light brown to grey fur, nearly hairless, scaly tail.
- Norway rat: body length of up to 28 cm and about 0.5 kg, small ears, droppings about 2 cm long.
- The deer mouse is the main carrier of hantaviruses in Canada.
How to recognize it
The deer mouse is the size of a house mouse, but its fur is clearly two-toned: brown or grey on the back, white on the belly and feet. Its tail is covered with fine hair, dark on top and white underneath. Its ears and eyes are large and prominent. Its close relative, the white-footed mouse, looks exactly like it.
The house mouse has more uniform fur and a nearly hairless, scaly tail as long as its body.
The Norway rat (Rattus norvegicus), also called the brown rat or sewer rat, is bulky: blunt snout, small ears, thick tail slightly shorter than its body.
| Criterion | Deer mouse ("mulot") | House mouse | Norway rat |
|---|---|---|---|
| Body size | Similar to the house mouse | 6.5 to 9.5 cm | Up to 28 cm (about 40 cm including the tail) |
| Fur | Brown or grey back, white belly and feet, sharp contrast | Light brown to dark grey, belly slightly paler | Greyish brown, paler belly |
| Tail | Hairy, dark on top and white underneath | Nearly hairless, scaly, as long as the body | Thick, scaly, slightly shorter than the body |
| Ears and eyes | Large ears, big prominent eyes | Large ears, pointed snout | Small ears, small eyes, blunt snout |
| Droppings | 3 to 6 mm, rod-shaped | 3 to 6 mm, rod-shaped with pointed ends | About 2 to 2.5 cm |
| Gets through | A gap barely the width of a 10-cent coin | A hole the size of a 25-cent coin | |
Where is it found in a Montreal home?
The deer mouse lives mainly in woods, fields and semi-rural areas. It mostly comes inside in the fall, into cottages, sheds, garages and homes next to a park or wooded area.
The house mouse is the city mouse. It settles in year-round inside walls, behind appliances, under kitchen cabinets and in the basement, with a peak of entries in the fall. The Norway rat digs burrows at ground level and prefers damp places: backyards, compost, under sheds, basements, sewers. Common signs: noises in the walls at night, gnawed packaging, droppings.
Is it dangerous?
According to Health Canada, the deer mouse is the main carrier of hantaviruses in the country. People are mainly infected by breathing in particles from dried droppings, urine or nests, stirred up by sweeping or vacuuming. The disease is rare, but it can cause serious, sometimes fatal, lung illness.
To clean up rodent droppings, the Public Health Agency of Canada recommends:
- wearing rubber gloves and, in an enclosed space, an N95 mask;
- never sweeping or vacuuming droppings;
- spraying a disinfectant, or one part bleach to 9 parts water, then letting it sit for 10 minutes;
- picking everything up with paper towels, throwing it all out in a double plastic bag and washing your hands thoroughly.
House mice and rats also contaminate food and surfaces, and gnaw on insulation and electrical wires.
How to get rid of it
Start by sealing entry points and removing whatever attracts them:
- Install metal door sweeps and caulk windows and foundation cracks.
- Plug holes around pipes with steel wool; cover dryer exhausts and vents with fine metal mesh.
- Store food in metal or glass containers.
- Keep garbage bins and compost closed; raise firewood about 30 cm off the ground.
- Set snap traps along the walls, about one per metre, baited with peanut butter. Check them every day.
A professional starts with an inspection before any treatment, seals entry points, then sets up traps and secured stations with products registered by Health Canada, applied according to the label. For mice, it usually takes 2 visits, with a follow-up 15 to 20 days later depending on the infestation, and a 6-month written guarantee. For rats, plan on 3 visits in total: the follow-up happens as soon as there are captures, otherwise 10 days later at the latest, with a 1-year written guarantee.
When to call an exterminator
Call if you see droppings in several rooms, if you hear scratching in the walls several nights in a row, if you're still catching them after a week of trapping, or if a garage is covered in deer mouse droppings. With a rat, don't wait. See our pages mouse exterminator in Montreal and rat extermination in Montreal. Our vehicles are unmarked.
Frequently Asked Questions
Is a deer mouse really a mouse?
Yes. In Quebec, the French word "mulot" usually refers to the deer mouse, a wild mouse of the genus Peromyscus. You can recognize it by its white belly and feet and its hairy tail, dark on top and white underneath.
How can I tell if I have a mouse or a rat?
Look at the droppings: mouse droppings measure 3 to 6 mm, Norway rat droppings about 2 to 2.5 cm. The rat is also much bigger, with small ears and a blunt snout.
Do deer mice transmit hantavirus?
According to Health Canada, the deer mouse is the main carrier of hantaviruses in the country. People are mainly infected by breathing in dust from dried droppings, urine or nests. The disease is rare but serious.
How many visits does it take to deal with a mouse or rat problem?
For mice, it usually takes 2 visits, with a follow-up 15 to 20 days later depending on the infestation, and a 6-month written guarantee. For rats, plan on 3 visits in total, with a follow-up as soon as there are captures, otherwise 10 days later at the latest, and a 1-year written guarantee.
Seeing this insect in your home? Our certified technicians serve Montreal, Laval, the North Shore and the South Shore, 24 hours a day. Request a free quote or call (438) 835-8401.
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