How to Identify Types of Ants

Acrobat Ants

Acrobat ants (Crematogaster genus) are found across the U.S. and are a favorite of Entomologist Charles Armstrong. “Simply because I love—if you’ll excuse the pun—their cute little heart-shaped abdomens and the fact that they’re also aptly called Valentine ants,” he says.

• How to identify acrobat ants: These 2.5 to 3mm long ants have the unique ability to lift their abdomen over their heads. Entomologist Kait Chapman says they have a two-node petiole (waist) and one pair of spines on the thorax (mid-section connecting to the legs).
• Do acrobat ants bite or sting? They can bite when provoked, but the pain isn’t significant.
• Are acrobat ants dangerous? Chapman says these moisture-loving ants nest in dead or rotting wood, but they don’t cause structural damage.
• Acrobat ant management: “Effective management involves the removal of infested wood and addressing any underlying moisture issues,” she says.

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Argentine Ants

South American native Argentine ants (Linepithema humile) are invasive pests across the U.S. They’re often confused with the odorous house ant but don’t emit a noticeable smell when crushed. Entomologist David Price explains that colonies can coexist to form supercolonies.

• How to identify Argentine ants: 3 to 4mm long, reddish brown, a single-node, pointed petiole and spineless thorax. As with many ant species, you might need a microscope or magnifying glass to see any of their distinguishing features.
• Do Argentine ants bite or sting? No
• Are Argentine ants dangerous? Though Argentine ants aren’t dangerous, Price explains that super colonies can be large and difficult to control if they enter homes searching for food and water. They also protect honeydew-producing, sap-feeding insects, like aphids and scale, in exchange for access to the sugary liquid, which can damage plants in your yard.
• Argentine ant management: Professional ant pest control is often best when a super colony nests on your property.

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Big-Headed Ants

The big-headed ant (Pheidole megacephala) is another problematic invasive species found in southern North America. Sometimes confused with subterranean termites, these soil-nesters can leave piles of loose, sandy soil in your yard.

• How to identify big-headed ants: Major workers have large heads and are around 4mm long, while minor workers are around 2mm long and reddish brown. Both have a two-part petiole and long body hairs.
• Do big-headed ants bite or sting? They don’t sting; a bite is rare and not painful.
• Are big-headed ants dangerous? Nope. However, while they don’t cause structural damage, large colonies can be numerous and extend across property lines.
• Big-headed ant management: Hire a professional pest control company to get large populations under control.

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Carpenter Ants

Carpenters ants (Camponotus spp.) are among the most common and damaging ants for homeowners across North America. Armstrong, who works in Maine, explains they cause problems for cabins and second-home owners in the woods. “They aren’t there for large portions of the year, and problems may not be discovered until the ants have already established a strong foothold somewhere inside the structure,” he says.

• How to identify carpenter ants: Hefty for an ant at 1/4 to 1/2 an inch long, Chapman says carpenters can be black or black and red and have a one-node petiole, evenly rounded thorax and hairs on the abdomen. Reproductive swarmers have wings.
• Do carpenter ants bite or sting? They occasionally bite in self-defense, but it’s rarely serious.
• Are carpenter ants dangerous? Carpenter ants can become hazardous if left unaddressed. “Unlike termites, carpenter ants do not consume wood but excavate galleries within it, making them a significant concern for structural damage,” Chapman says.
• Carpenter ant management: Integrated pest management specialist Jody Ganglogg-Kaufmann says baits can be effective for getting rid of carpenter ants, but because large colonies have the potential to cause costly structural damage, she recommends hiring a professional.

Citronella Ants

There are two types of citronella ants: the large yellow ant (Lasius interjectus) and the small yellow ant (Lasius claviger). When threatened or crushed, both ants smell like citronella.

• How to identify citronella ants: Chapman describes these ants as having a one-node petiole, an unevenly shaped thorax and hairs on the abdomen. Both are very small, measuring 3 to 4.5mm long.
• Do citronella ants bite or sting? No.
• Are citronella ants dangerous? Not really. “They’re primarily a nuisance when swarming in or around homes,” Chapman says. However, they aren’t a significant issue and can be beneficial, as they feed on plant-damaging aphids.
• Citronella ant management: “Swarming ants can be removed using a vacuum,” Chapman says.

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Fire Ants

People with a phobia of ants often fear fire ants’ sting. Many types of ants never or rarely sting, and when they do, it isn’t too painful. However, the black and red species of imported fire ants (Solenopsis richteri and Solenopsis invicta) and the European fire ant (Myrmica rubra) have rightfully earned a fearsome reputation.

Found across many parts of the U.S., when you come across a nest, “leisurely, simple activities, like gardening or walking the dog, can become nearly impossible,” Armstrong says.

• How to identify fire ants: Varies, depending on the species, but if you receive a painful sting, there’s a good chance you’re dealing with a fire ant.
• Do fire ants bite or sting? Yes.
• Are fire ants dangerous? These ants aggressively defend their nests. “The stings are painful, and humans and pets alike are often covered in dozens or more of them in only a few short moments,” Armstrong says. If you’re allergic to the sting, it can be life-threatening.
• Fire ant management: “Their colonies can become quite complex, and just as soon as a mound is destroyed, another pops up,” Price says. Given their prolific nature and powerful stings, don’t delay calling the professionals.

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Ghost Ants

Ghost ants (Tapinoma melanocephalum) get their name from their pale exoskeleton. They thrive in the tropical climates of Florida and Hawaii.

• How to identify ghost ants: Tiny workers measure 1.3 to 1.5mm long. The head and thorax are dark brown, and the legs and gaster (back end of the body) are opaque or white.
• Do ghost ants bite or sting? Ghost ants have no stinger. They may bite when threatened, but the bites are insignificant.
• Are ghost ants dangerous? More of a nuisance than a danger, these adaptable pests nest indoors (often in wall voids) or outdoors and are attracted to sweet foods.
• Ghost ant management: For any foraging species, Chapman recommends you “clean spills, store food in sealed containers and practice exclusion through sealing cracks, crevices, and gaps.” If they become a major nuisance, try using sugary bait.

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Harvester Ants

Over 22 species of seed-collecting Harvester ants call the U.S. home. Although they rarely enter homes, they can be a nuisance in yards.

• How to identify harvester ants: 1/5 to 1/2-inch long, black, brown or red, two-node petiole.
• Do harvester ants bite or sting? They can bite aggressively while defending their nest.
• Are harvester ants dangerous? No, but they create large sand mounds, strip vegetation around nesting sites, and their bite is painful.
• Harvester ant management: Using granular baits around nest opening sites can control populations.

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Little Black Ants

Little black ants (Monomorium minimum) are adaptive, opportunistic foragers and common house pests in southeastern regions. You might see a trail of them leading from spilt cereal in your pantry.

• How to identify little black ants: Tiny workers are black, measure 1.5 to 2mm long, and have a two-node petiole.
• Do little black ants bite or sting? They have stingers, but the pain isn’t significant.
• Are little black ants dangerous? Nope. While they can nest in homes, but colonies don’t spread out of control as fast as some species.
• Little black ant management: Chapman suggests following foraging ants to reveal their nest location and, if it’s easily accessible, use an insecticide to treat the colony directly. “However, given ants propensity for foraging long distances, this approach may prove challenging. In such cases, insecticidal baits offer a convenient alternative,” she says.

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Odorous House Ants

“The odorous house ant [Tapinoma sessile] is a peridomestic ant, meaning it thrives in the human environment,” Gangloff-Kaufmann says. “They’re called ‘tramp’ ants because when disturbed, smaller satellite colonies pick up and leave to find a new nesting site,” she says. This home-invading species is widespread across the U.S.

• How to identify odorous house ants: Chapman says these black, 2.5 to 3mm long ants have a one-node petiole hidden by the abdomen and an uneven-shaped thorax. When crushed, they emit a rotten smell.
• Do odorous house ants bite or sting? Rarely bites and doesn’t sting.
• Are odorous house ants dangerous? “The Odorous house ant can become a large nuisance as they have 12 queens with large colonies that overrun other ant species, making them difficult to control,” Price says.
• Odorous house ants management: “They respond well to sugary baits, so this is the best option for management inside,” Gangloff-Kaufmann says. “However, there’s no way to eliminate OHA from a whole property or area.”

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Pavement Ants

“Pavement ants (Tetramorium immigrans) are the type that nest under concrete slabs and pavers, leaving piles of sand on the surface,” Gangloff-Kaufmann says. They’re especially prevalent in the Northwest and Midwest.

• How to identify pavement ants: “Two-node petioles, one pair of spines on the thorax, workers are 1/8-inch long and reddish-brown-black in color,” Chapman says.
• Do pavement ants bite or sting? They can sting but rarely do, and it isn’t overly painful.
• Are pavement ants dangerous? Gangloff-Kaufmann says these ants aren’t harmful to people, but could present a structural hazard. “Over time, their excavations under man-made hardscapes will undermine those structures.”
• Pavement ant management: Gangloff-Kaufmann suggests using baits, and Chapman says it’s possible to locate and treat outdoor nests directly.

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Pharaoh Ants

Pharaoh ants (Monomorium pharaonis) are hungry, invasive scavengers that frequent establishments with unlimited food sources, such as restaurants, hotels, grocery stores and hospitals.

• How to identify pharaoh ants: Very small (1.5 to 2mm long), two-node petiole, spineless thorax, and yellow to red.
• Do pharaoh ants bite or sting? Rarely.
• Are pharaoh ants dangerous? “Pharaoh ants are known to transmit over a dozen pathogens and are a threat to medical and food facilities,” Price says. “They’re small and can splinter into smaller colonies, making them difficult to control.”
• Pharaoh ant management: Because of their disease-carrying potential, it’s best to seek professional help to get rid of these ants.

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Pyramid Ants

Docile pyramid ants (Dorymyrmex bureni) are most common in southern regions of the U.S. They aren’t a major nuisance as they don’t enter houses and are non-confrontational.

• How to identify pyramid ants: 3 to 3.5mm long workers, yellowish-orange to orange-brown, one-node petiole, triangular projection on top of their thorax and emits an unpleasant odor.
• Do pyramid ants bite or sting? Won’t bite unless provoked.
• Are pyramid ants dangerous? No, though they can create unsightly, crater-shaped mounds that might necessitate lawn repair. On the plus side, they prey upon problematic pest species in your yard.

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Slender Twig Ants

The slender twig ant (Pseudomyrmex gracilis) is widespread in the southeastern U.S. and nests in a wide range of vegetation.

• How to identify slender twig ants: Big ants measuring 8 to 10mm long, with an elongated and wasp-like body, two-node petiole and large eyes. Colors vary.
• Do slender twig ants bite or sting? They have a painful sting.
• Are slender twig ants dangerous? Nope. While their sting is not pleasant, you won’t typically find them in large numbers, so management isn’t typically a requirement.

Tawny Crazy Ants

Also known as the raspberry ant (Nylanderia fulva), this invasive species is predominantly found in the southeastern U.S. Entomologist Jason Williams explains that they’re “supercolonial” ants, meaning that populations are genetically similar, don’t recognise boundaries between each other and are interconnected and cooperative.

• How to identify tawny crazy ants: About 2.5 to 3mm, yellow-brown to orange-brown and covered in spiky hairs. Their name comes from their quick and erratic movement.
• Do tawny crazy ants bite or sting? “If disturbed, they will bite and excrete formic acid, which causes brief pain that fades quickly,” Price says.
• Are tawny crazy ants dangerous? Williams explains these seriously invasive pests can cost hundreds of millions of dollars annually in the U.S. “They’re well known for nesting in and damaging electrical equipment,” he says.
• Tawny crazy ant management: “Because infestations can cover large areas, it can be near impossible for an individual homeowner to manage them on their own,” Williams says. “Perimeter sprays around the house are ineffective because the ants will continuously pile up at the walls of the house until, eventually, ants can cross the dead bodies of other ants to enter the home without contacting the pesticide.” This phenomenon is known as “crazy ant drift.” Williams recommends implementing control measures early before populations explode and suggests fipronil baits as a good first line of defense.

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Texas Leafcutter Ants

Leafcutter ants are iconic because of the images of them carrying pieces of leaf much larger than their bodies. They cut and gather this vegetation to grow fungus on in their nests for food. Mostly found in tropical regions, the most common of these species in the U.S. is the Texas leafcutter ant (Atta texana), which thrives in the heat of the southern states.

• How to identify leafcutter ants: Brown, 4mm to 12mm long, prominent spines on the thorax.
• Do leafcutter ants bite? Their strong mandibles can draw blood.
• Are leafcutter ants dangerous? No, they’re more of a nuisance. Rarely do these ants enter homes, but they can wreak havoc on the plants in your yard.
• Leafcutter ant management: Their nests are large and complex, and it’s tricky to control colonies. You can protect your plants by spraying them with appropriate insecticides.

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Thief Ants

Tiny thief ants (Solenopsis molesta) get their name from their pilfering proclivities.

• How to identify thief ants: Chapman describes them as having a two-node petiole and no spines on the thorax. She says the workers measure 1/20-inch long, are orange-brown, and are often confused with pharaoh ants.
• Do thief ants bite or sting? Yes, but only when threatened.
• Are thief ants dangerous? Theif ants can present a food safety hazard. Chapman says these prolific counter surfers prefer greasy proteinaceous foods and will steal and eat larvae from nearby ant nests.
• Thief ant management: Chapman recommends using protein-based baits.

Winter Ants

Also known as the false honey ant (Prenolepis imparis), this native North American species is found nationwide. “They’re known as “winter” ants because they forage in cold weather when no other ants are active,” Williams says.

• How to identify winter ants: “Worker ants are 3-4mm long and can come in various shades from light to dark brown, sometimes even reddish,” Williams says. “Their mesosoma (thorax) is strongly constricted right behind their front pair of legs, making their body look sort of like a little ‘peanut’ or ‘hourglass’ shape.”
• Do winter ants bite or sting? Bites are rare and mild.
• Are winter ants dangerous? Williams says these ants aren’t problematic pests and seldom go indoors. They typically nest at the base of shady trees in old-growth forests.
• Winter ant management: If you have flying ant intruders, keep them out by sealing possible entry routes around doors and windows.

White-Footed Ants

White-footed ants (Technomyrmex difficilis), often confused with Argentine ants, are becoming an increasing household nuisance in the southeastern U.S.

• How to identify white-footed ants: 2.5 to 3mm long, brownish-black to black, yellowish-white feet and one-node petiole.
• Do white-footed ants bite or sting? No.
• Are white-footed ants dangerous? While they don’t cause structural damage, these ants are prolific and love sugary foods. They will forage in your kitchens and protect sweet honeydew-producing aphids, which can be a problem for plants.
• White-footed ant management: Their large colony sizes make control challenging, but sweet baits can be effective ant killers. Chapman suggests strategically placing baits where ant activity is high. “This ensures foragers carry the poison back to the colony, effectively eradicating it,” she says.

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FAQs

What is the biggest ant in the world?

Dinoponera gigantea, a giant Amazonian ant species, is believed to be the largest ant in the world. Female ants can measure over 1.5 inches (4cm) long. However, you won’t see this whopper in the U.S. It’s only found in South America.

Do ants have stingers?

“All ants may bite incidentally or when defending their colony, and some have stingers,” Chapman says. However, only a few species in the U.S. are medically significant, such as the imported fire ants, and typically only when individuals have an allergic reaction.

What ant management hacks should I avoid?

There are lots of suggested hacks for getting rid of ants. Armstrong doesn’t recommend pouring boiling water over outdoor anthills. “That may set them back a little, but it’s usually only a short-term fix.” He also recommends steering clear of oatmeal treated with Borax or homemade solutions of sugar and Borax together. “Also, I don’t believe Diatomaceous Earth is a very good long-term solution because it doesn’t target the queen,” he says.

About the Experts

• Charles Armstrong is the Cranberry Professional and Staff Entomologist at the University of Maine. He provides integrated pest management education and on-site assistance and conducts insect and spider identification in the University’s Cooperative Extension Diagnostic and Research Laboratory; email interview, 14. Jun, 2024.

• Kait Chapman is an Extension Educator of Urban Entomology at the University of Nebraska-Lincoln. She received her Bachelor’s degree in Insect Science and Master’s in Entomology at the University; email interview, 11. Jun, 2024.
• Jody Gangloff-Kaufmann, PhD, is the Associate Director of Community & Urban Integrated Pest Management at Cornell University. She works to reduce pest risks and increase awareness of safe and effective pest management tools in non-agricultural settings; email interview, 14. Jun, 2024.
• David Price is the Director of Technical Services and Associate Certified Entomologist with Mosquito Joe, a Neighborly company; email interview, 12. Jun, 2024
• Jason Williams, PhD, works in the Entomology and Nematology Department at the University of Florida. His research focus is ant systematics, biogeography, and taxonomy; email interview, 14. Jun, 2024.