Ants
Carpenter Ant
The largest and most damaging ant in Northern Ontario. Carpenter ants tunnel into damp or damaged wood to build their nests.
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Quick facts
- Size
- 6–13 mm (workers)
- Colour
- Black, sometimes with reddish parts
- Active season
- Spring to fall; year-round if nesting indoors
- Where found
- Damp or rotting wood, wall voids, window frames, decks
How to Identify
- Large black ant, often over 6 mm long
- Evenly rounded back when viewed from the side
- A single bump (node) between the thorax and abdomen
Signs to Look For
- Small piles of sawdust-like wood shavings (frass)
- Large ants indoors, especially at night or in early spring
- Faint rustling sounds inside walls
- Winged ants indoors in spring
Why It Matters
- Hollow out wood, weakening sills, frames and structural members
- Often point to a moisture problem in the building
- Satellite colonies can spread through a home
Prevention Tips
- Fix leaks and replace damp or rotting wood
- Trim branches touching the roof or walls
- Store firewood away from the house and off the ground
- Seal gaps around utility lines
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Big-Headed Ant
A small, light-brown ant whose larger workers have oversized heads.
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Citronella Ant
A yellow ant named for the lemon-like smell it gives off when crushed.
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European Fire Ant
An invasive, reddish-brown ant that stings aggressively when its nest is disturbed.
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Pavement Ant
Small, dark brown ants that nest under sidewalks, driveways and slabs, and often trail indoors looking for food.
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