Identify Your Pest Rodents Deer mouse
Deer mouse
Also called: Deermouse
The deer mouse is a native Alberta mouse with a tan to reddish-brown back, white belly and white feet. People notice it in fall and winter, when it moves into garages, sheds, cabins and rural homes, and because it is the main hantavirus carrier in Alberta.
Size 7 to 10 cm body; tail shorter or as long
Colour Tan to reddish-brown back, bright white belly and white feet
Key feature Sharply two-toned, hairy tail: dark on top and white underneath
Season Active all year outdoors; moves into buildings in fall and winter
Where Garages, sheds, cabins, RVs, farm buildings and rural or acreage homes
What it looks like
The deer mouse is a little larger than a house mouse and looks cleaner and more colourful. Its back is tan to reddish-brown, with a sharp line where the fur turns bright white on the belly. The feet are white. The eyes are large and dark, and the ears are big for its size.
The tail is the clearest clue. It is covered in short hair and is clearly two-toned, dark on top and white underneath. Deer mice often store seeds and build nests of shredded material in quiet, closed spaces such as drawers, boxes, stored furniture and vehicle engine bays.
Often confused with
House mouse
Meadow vole
Signs to look for
Droppings in closed spaces
Hidden seed stashes
Shredded nests
Chewed items
Risks and damage
In Alberta, deer mice are the main carrier of hantavirus. People can catch it by breathing in dust from dried droppings, urine or nesting material, usually while cleaning closed sheds, cabins or garages. Cases are rare, but the illness can be serious. Deer mice also chew wiring, insulation and stored items, and their nests can foul vehicles, furniture and stored gear.
In Alberta
Deer mice are native and live across Alberta, from farmland and parkland to forest edges. Around Edmonton and Calgary, people meet them most on acreages, farms and the edges of towns. They move indoors in fall and winter, so spring cleanups of sheds and cabins often reveal them.
Deer mice store food for winter. People often find a hidden stash of seeds, grain or dog food in a boot, a drawer or even a car’s engine air filter.
How to keep them out
Seal outbuildings
Use hard bins with lids
Remove food sources
Clear cover near buildings
Check stored vehicles and RVs
When it is time to bring in a professional
Call a professional if you find many droppings or nests in a cabin, shed, garage or crawl space, or if mice keep getting into a rural home. Large messes in closed spaces need extra care. Technica’s licensed technicians can remove deer mice, find entry points and advise on safe cleanup.
Frequently asked questions
Do all deer mice carry hantavirus?
No. Only some deer mice carry the virus, and you cannot tell by looking at them. That is why all deer mouse droppings, urine and nests should be handled with care. Hantavirus is not easily passed from person to person.
How should I clean up deer mouse droppings?
Treat every mess as if it carries the virus. Never sweep or vacuum it, since that stirs up dust. Air the building out for half an hour, then glove up. Soak droppings and nests with 1 part bleach to 9 parts water for 5 minutes, then bag, seal and wash up. For a big mess in a closed space, ask Health Link first.
What are the signs of hantavirus illness?
It often starts like a bad flu, with fever, chills, aching muscles and sometimes an upset stomach. It usually shows up 1 to 2 weeks after contact, but can take up to 5. If you feel sick after a mouse cleanup, get medical care promptly and say you were exposed. Trouble breathing needs care right away.