IDENTIFICATION GUIDE
Ontario Pest Library
Identify common pests found in Ontario homes and businesses. Learn what they look like, where they hide, and when to call a professional.
39 Common Ontario Pests
🔍 Identification Details
📞 Same-Day Service Available
✅ Health Canada Approved
Use this Ontario pest identification library to identify insects, rodents, and wildlife commonly found in Ontario homes and businesses. Select a category below, or browse all 39 pests. Not sure what you’re dealing with? Call 1-855-501-0074 for a free same-day assessment — serving Toronto, Mississauga, Brampton, Hamilton, Oakville, Burlington, and 57+ Ontario cities since 2016.
🐜 ANTS
Ants
Carpenter Ant
Size:Workers 6–13 mm; Queen 25 mm+
Colour:Reddish-brown or black
Notes:Large mandible, rounded thorax, single node, cone hairs on tip of abdomen
European Fire Ant
Size:4–5 mm
Colour:Red to dark reddish-brown
Notes:Two-segmented waist (petiole), stinger present, painful sting, builds mounds in lawns
Little Black Ant
Size:1.5–2 mm
Colour:Jet black
Notes:Two-segmented pedicel, 12-segmented antennae, found in woodwork and masonry
Pharaoh Ant
Size:1.5–2 mm
Colour:Yellow to light brown
Notes:Multi-node waist, very small, common in hospitals and food facilities
Pavement Ant
Size:2.5–3 mm
Colour:Dark brown to black
Notes:Parallel lines on head and thorax, two spines on back, nests under pavement and slabs
🪳 COCKROACHES
Cockroaches
German Cockroach
Size:Adult 10–15 mm
Colour:Yellowish-brown
Notes:Two dark parallel bands on pronotum; most common indoor species; rapid reproducer
Brown-Banded Cockroach
Size:10–14 mm
Colour:Light brown
Notes:Two lighter bands across wings and abdomen; prefers warm, dry locations away from water
Oriental Cockroach
Size:Male 18–29 mm; Female 20–27 mm
Colour:Dark brown to black
Notes:Shiny body; strong musty odour; prefers cool, damp areas like basements and drains
American Cockroach
Size:35–40 mm
Colour:Reddish-brown
Notes:Yellowish figure-8 pattern behind head; largest common cockroach; can fly short distances
Pennsylvania Wood Cockroach
Size:20–25 mm
Colour:Dark brown
Notes:White or cream border on thorax and wing tips; attracted to lights; enters homes from firewood
🛏️ BED BUGS
Bed Bugs
Bed Bug
Size:4–5 mm
Colour:Reddish-brown
Notes:Flat oval body; swells and darkens after feeding; nocturnal; detected by blood spots or shed skins
🐭 RODENTS
Rodents
Norway Rat
Size:Body 18–25 cm; tail shorter than body
Colour:Brown-grey
Notes:Blunt snout, small ears, heavy body; burrows in soil; leaves gnaw marks and greasy rub marks
House Mouse
Size:Body 7–10 cm
Colour:Grey-brown
Notes:Large ears, pointed snout; leaves droppings the size of rice grains; nests in insulation and wall voids
🐛 OTHER INSECTS
Other Insects
Centipede
Size:25–50 mm
Colour:Yellow-grey with dark stripes
Notes:15 pairs of long legs; very fast; prefers damp areas; venomous but rarely harmful to humans
Silverfish
Size:12–19 mm
Colour:Silver-grey
Notes:Fish-like movement; three tail filaments; feeds on starch, paper, glue and textiles
Fleas
Size:1.5–3.3 mm
Colour:Dark reddish-brown
Notes:Laterally compressed; powerful hind legs for jumping; feeds on blood of mammals and birds
Black Carpet Beetle
Size:2.8–5 mm
Colour:Black
Notes:Oval body; larvae are destructive to natural fibres, wool, fur, feathers and stored food
Box Elder Bug
Size:11–14 mm
Colour:Black with red markings
Notes:Distinctive red veins on wings; clusters on south-facing walls; enters homes in autumn
European Earwig
Size:10–15 mm
Colour:Grey to brownish-grey; flat, oval segmented body with two rear appendages
Notes:Flat body with distinctive pincers (cerci) at rear; nocturnal; attracted to moisture and light; found under mulch, rocks, and debris; enters damp basements and crawlspaces.
Pill Bug
Size:10–15 mm
Colour:Grey to brownish-grey; flat, oval segmented body with two rear appendages
Notes:CAN roll into a tight ball (armadillo-like defence); found in moist soil, under rocks, logs, and mulch; harmless decomposer; often found in damp basements and garden areas.
Sow Bug
Size:10–15 mm
Colour:Grey to brownish-grey; flat, oval segmented body with two rear appendages
Notes:Cannot roll into a ball (unlike Pill Bug); flatter body with two tail appendages; found under rocks, mulch, and organic debris; attracted to moisture; harmless but indicates excess dampness.
🕷️ SPIDERS
Spiders
Northern Black Widow Spider
Size:Female 8–10 mm body
Colour:Shiny black
Notes:Red or orange hourglass marking on underside; highly venomous; builds irregular tangled webs
Brown Spider
Size:6–20 mm
Colour:Brown to tan
Notes:Violin-shaped marking on back; reclusive; bite can cause necrotic skin reaction in rare cases
🐦 BIRDS
Birds
House Sparrow
Size:14–16 cm
Colour:Brown-grey with black bib
Notes:Stout bill; colonial nester; builds messy nests in vents, gutters and building cavities
Starling
Size:19–22 cm
Colour:Iridescent black with white speckles (winter)
Notes:Short tail, long bill; flocks in murmurations; nests in building cavities and roof spaces
Feral Pigeon
Size:29–37 cm
Colour:Blue-grey, variable
Notes:Iridescent neck feathers; roosting causes damage from acidic droppings; carries ectoparasites
🪰 FLIES
Flies
House Fly
Size:6–7 mm
Colour:Grey with four dark stripes on thorax
Notes:Sponging mouthparts; breeds in decaying organic matter; major vector of food-borne pathogens
Drain Fly
Size:1.5–5 mm
Colour:Grey-brown
Notes:Moth-like wings; breeds in organic slime in drains and sewers; weak flier
🐝 WASPS & BEES
Wasps & Bees
Umbrella Wasp
Size:15–22 mm
Colour:Black and yellow
Notes:Paper nest with open cells (umbrella shape); aggressive when nest is disturbed; multiple stings
Yellow Jacket
Size:12–16 mm
Colour:Bright yellow and black
Notes:Hairless body; builds papery nests underground or in wall voids; very aggressive in late summer
Honey Bee
Size:15 mm
Colour:Golden yellow with brown bands
Notes:Fuzzy body; colonial; swarms in spring; important pollinator — removal preferred over extermination
Bumble Bee
Size:15–25 mm
Colour:Black and yellow, fuzzy
Notes:Large robust body; ground or cavity nester; important pollinator; stings only when threatened
European Hornet
Size:25–35 mm
Colour:Brown with yellow-orange markings
Notes:Largest European wasp; builds paper nests in tree hollows and wall cavities; nocturnal activity
🦋 MOTHS
Moths
Indian Meal Moth
Size:Wingspan 14–20 mm
Colour:Pale grey with copper-brown outer wings
Notes:Most common stored-food pest; larvae infest grains, cereals, nuts and dried fruit
🦝 WILDLIFE
Wildlife
Raccoon
Size:40–70 cm body; 5–14 kg
Colour:Grey-brown with black mask and ringed tail
Notes:Nests in attics, chimneys, crawlspaces. Causes structural damage; spreads parasites and diseases.
Squirrel
Size:25–50 cm with tail; 300–700 g
Colour:Grey or reddish-brown; white/cream underside
Notes:Chews soffits and fascia to enter attics. Gnaws electrical wiring — serious fire hazard.
Skunk
Size:40–70 cm with tail; 1.5–5 kg
Colour:Black with white stripe(s) along back
Notes:Burrows under porches and foundations. Sprays potent odour; common rabies carrier in Ontario.
Chipmunk
Size:15–18 cm with tail; 70–140 g
Colour:Reddish-brown with dark and light stripes
Notes:Digs burrow systems near foundations and patios. Can undermine walkways and retaining walls.
Opossum
Size:38–50 cm body; 0.8–6 kg
Colour:Grey-white; pointed white face with pink nose
Notes:North America’s only marsupial. Shelters under decks, scavenges garbage; carries fleas, ticks, leptospirosis.
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