Pharaoh Ant

Monomorium pharaonis

Size1.5–2 mm

Colony Size1,000–300,000

Active Season:Active year-round indoors. No outdoor swarming in Canada.

Tiny yellow-brown ants that nest exclusively indoors in Canada. A serious pest in hospitals, food facilities, and apartments.

Anatomy

Anatomical Details

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Identification

ColourVery small (1.5-2mm), pale yellow/orange body with a darker abdomen tip

Size1.5–2 mm

Distinguishing Features

Very small—among the tiniest household ants
Two nodes between thorax and abdomen
12-segmented antennae with 3-segment club
No stinger capable of piercing skin

Similar Species

Pavement ants are larger (3-4mm) and darker brown.
Thief ants are similar size but paler yellow with smaller eyes.

Biology

Lifecycle

Egg to adult in 38-45 days at room temperature. Strictly relies on 'budding' (splitting the colony) rather than mating flights. A single colony can split into dozens if threatened—a major control challenge.

Diet

Prefer proteins and fats. Will feed on grease, sweets, dead insects, and even IV solutions in hospitals.

Nesting

Exclusively indoors in Canada. Nest in warm, humid voids near food and water: wall cavities, under floors, in equipment.

Signs of Infestation

Tiny ants trailing along edges

Follow walls, counters, and baseboards in thin lines. Most active at night.

Ants near moisture sources

Check under sinks, around toilets, near dishwashers and refrigerators.

Multiple trailing routes

Unlike other ants, pharaoh ants maintain several simultaneous trails.

Ants in unusual locations

Found in electrical outlets, behind wallpaper, inside appliances.

Where They Nest

Kitchen and bathroom wall voids
Behind baseboards and door frames
Inside electrical boxes and outlets
Under refrigerators and dishwashers
Heating system ductwork
Electrical outlets and junction boxes
IV lines and medical tubing (in healthcare settings)

Common Nesting Sites

Nesting Site Details

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Distribution in Canada

Found in heated buildings nationwide. Cannot survive Canadian winters outdoors.

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Active Season

Active year-round indoors. No outdoor swarming in Canada.

House Types at Risk

This pest is commonly found in these home types

Condo / Apartment

High Risk

Shared walls and utility chases allow colonies to spread building-wide. Coordinated treatment essential.

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Townhouse

High Risk

Party walls enable colony spread between units. Budding can quickly affect entire row.

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Bi-Level

Moderate Risk

Multiple floor levels with utility penetrations create pathways. Warm, humid bathroom conditions attract nesting.

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Prevention

DO NOT USE SPRAYS (Raid, etc.). Spraying causes 'budding,' where the colony fractures and spreads to multiple new locations, making the infestation exponentially worse.
Seal all cracks and gaps in walls and around pipes
Eliminate food sources—clean up crumbs and spills immediately
Fix any moisture issues promptly
Inspect incoming shipments and supplies
In multi-unit buildings, coordinate treatment across units

Professional Treatment

Baiting is the ONLY effective method. Sprays cause colony budding, spreading the infestation. Professional baiting programs take 2-4 weeks but eliminate colonies completely.

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Frequently Asked Questions

What does a Pharaoh Ant eat?

Prefer proteins and fats. Will feed on grease, sweets, dead insects, and even IV solutions in hospitals.

Where does a Pharaoh Ant nest?

Exclusively indoors in Canada. Nest in warm, humid voids near food and water: wall cavities, under floors, in equipment.

When is a Pharaoh Ant most active?

Active year-round indoors. No outdoor swarming in Canada.

What are the signs of a Pharaoh Ant infestation?

Tiny ants trailing along edges: Follow walls, counters, and baseboards in thin lines. Most active at night. Ants near moisture sources: Check under sinks, around toilets, near dishwashers and refrigerators. Multiple trailing routes: Unlike other ants, pharaoh ants maintain several simultaneous trails. Ants in unusual locations: Found in electrical outlets, behind wallpaper, inside appliances.

How can I prevent a Pharaoh Ant infestation?

DO NOT USE SPRAYS (Raid, etc.). Spraying causes 'budding,' where the colony fractures and spreads to multiple new locations, making the infestation exponentially worse. Seal all cracks and gaps in walls and around pipes. Eliminate food sources—clean up crumbs and spills immediately. Fix any moisture issues promptly. Inspect incoming shipments and supplies. In multi-unit buildings, coordinate treatment across units.

How is a Pharaoh Ant treated?

Baiting is the ONLY effective method. Sprays cause colony budding, spreading the infestation. Professional baiting programs take 2-4 weeks but eliminate colonies completely.

Scientific Classification