Common Types of Ants

Ants can cause serious problems for your business. Due to their size, it can be difficult to know what ant species you are dealing with and the risk that is associated with them. Use this guide to help identify the most common types of ants to help ensure you can confidently maintain a pest-free facility.

Acrobat Ant (Crematogaster)

Found throughout the U.S.; name derived from how it raises its abdomen over its head and thorax when disturbed
Workers are the same size, ¹⁄16” – ¹⁄8” (2.5 – 4 mm) long, light brown to black in colour, have 11-segmented antennae with a three-segmented club and a thorax with one pair of dorsal spines
Infests foam insulation and structures, preferring moisture-softened wood
Nests in moderate to large colonies, with swarmers active from mid-June to late September
Can sting, bite and emit a repulsive odour

Carpenter Ant (Camponotus)

Found throughout the U.S.; hollows out galleries in moist wood for nests, which can cause structural damage
Workers range in size from ¹⁄8” – ¹⁄2” (3.5 – 13 mm) long; are black with combinations of red and black, have 12-segmented antennae with no club, evenly rounded profile on upper side and no stinger
Colonies usually have one queen; can have satellite nests separate from main colony with no queen
Swarmers appear from May to August in the East and from February to June in the West
Do not sting, but can have painful bites and emit a strong acidic odour when disturbed

Odorous House Ant (Tapinoma sessile)

Found throughout the U.S.; named for strong, rotten coconut-like odour it produces when crushed
Workers are the same size and ¹⁄16” – ⅛” (2.4 – 3.3 mm) long, brown to black in colour, have 12-segmented antennae with no club; no stinger
Major structure-invading species; constructs nests near moisture sources such as voids near hot water pipes and around sinks
Prefers sweets but eats greasy foods such as meats and cheeses
Colonies have multiple queens; ants from different colonies are friendly and move along trails

Pavement Ant (Tetramorium caespitum)

Found in the eastern half of the U.S. and on the West Coast; named because nests are commonly located in pavement cracks
Workers are the same size, ¹⁄16” – ⅛” (2.5 – 3 mm) long, light brown to black with paler legs and antennae and a head and thorax that are furrowed/grooved with parallel lines; has 12-segmented antennae, with a three-segmented club, unevenly rounded profile and a thorax containing a pair of small spines
Nests inside walls, insulation and under floors and slabs near heat sources during winter
Swarmers appear outside in June and July but can emerge anytime inside; workers bite and sting only when provoked

Pharaoh Ant (Monomorium pharaonis)

Found throughout the U.S.; named for Linneaus’ mistaken belief that this ant was one of Egypt’s plagues during the time of the pharaohs
Workers are the same size, ¹⁄16” (1.5 mm) long with a pale, yellowish to reddish body and darker abdomen, an unevenly rounded profile, stinger and 12-segmented antennae with a three-segmented club
Nests inside warm, humid areas near food and water sources; common in commercial buildings; of concern in hospitals where they will enter patient wounds, IV bottles and tubes; can carry more than a dozen pathogenic bacteria
Nests are difficult to find as they tend to be hidden in wall voids and behind baseboards

Thief Ant (Solenopsis molesta)

Found throughout the U.S.
Workers are the same size, ¹⁄16” (1.3 mm) long, pale yellowish to dark brown, have 10-segmented antennae with a two-segmented club, an unevenly rounded profile and miniscule stinger
Nests near other ant species and robs them of food; forages in trails and prefers high-protein foods and sweets
Nests inside in small crevices, woodwork and masonry; commonly enters structures during hot weather
May carry disease, as it is known to feed on dead animals

More Resources

Ants: Complex, but Controllable Pest

With more than 12,400 species of ants in the world, controlling ants seems complex. By understanding ant behavior, you can easily eliminate them.

Pest Files: Locating Ant Nests

A major key to dealing with ants at your facility is knowing how to locate an ant nest and understanding what attracted the ants in the first place.