Types of Ants: How to Identify the Ant You Found

How many types of ants are there?

Scientists have named more than 15,700 species and subspecies of ants, and a 2022 study in PNAS suggests there may be as many again still waiting for names. The US has somewhere between 700 and 1,000 kinds, depending on the source. Yet only about two dozen types of ants are common in American homes and yards.

The same PNAS team put the number of ants alive on Earth at about 20 quadrillion. That is roughly 2.5 million ants for every person. So when a trail appears in your kitchen, it is a tiny slice of a very big group.

The US count is a number sources disagree on. PestWorld and the Missouri Department of Conservation say “more than 700”, while Western Exterminator and DoMyOwn put it near 1,000. Some states have a lot on their own: Texas A&M counts about 300 in Texas, and UC IPM counts about 270 in California. On iNaturalist, naturalists have photographed 673 ant species in the US with an expert-confirmed name (read October 21, 2026).

Older numbers still circulate, too. UC IPM’s ant guide says “more than 12,400” worldwide, which is below today’s count, because new species are named every year. For pests the list is short: Penn State’s pest key covers just 21 species that matter around buildings in North America.

The 10 most common types of ants in US homes

These are the ants that the extension guides we checked name most often as house pests. Each one has a short entry further down this page.

1. Odorous house ant, the small brown kitchen ant that smells of coconut when crushed.
2. Pavement ant, which piles soil in sidewalk and slab cracks.
3. Carpenter ant, the big black ant that nests in damp wood.
4. Argentine ant, which forms huge trails, above all in California.
5. Pharaoh ant, a tiny yellow ant of heated buildings.
6. Little black ant, a tiny, shiny black ant of lawns and kitchens.
7. Thief ant, also called the grease ant.
8. Fire ant, the stinging mound ant of the South.
9. Acrobat ant, which raises a heart-shaped abdomen when disturbed.
10. Field ant, the medium red, black or red and black ant of lawn mounds.

How to identify an ant in five checks

To identify an ant, use five checks in order. First make sure it is an ant, then measure it, note its color in daylight, and count the one or two nodes in its waist. Finally, note where you found it and smell a crushed one. Those five clues name most US house ants without a microscope.

The top-ranking guides list ants one by one but rarely let you sort the ant in your hand. These checks are the features a phone can see, so they work at the kitchen counter.

One node or two

The node is a small bump on the thin waist between the middle of the body and the abdomen. Some ants have one, and some have two in a row. Illinois Public Health calls the number and shape of the nodes “useful features for identifying ant species”. Seen from the side, even a zoomed phone photo often shows it.

One node points to odorous house, Argentine, carpenter, field, winter, crazy, ghost and citronella ants. Two nodes point to pavement, pharaoh, thief, fire, acrobat, harvester, big-headed and little black ants. However, on odorous house and ghost ants the single node hides under the abdomen, so look closely before you decide.

The crush-and-sniff test

Several ants give off a smell when crushed, and the smell is a fast, free clue. Crush one ant on a paper towel and sniff it. Then compare it with this table, which uses the descriptions in the extension guides.

What a phone photo can and cannot show

A sharp photo shows size, color and often the node count. But it rarely shows antenna segments, spines or hairs, and those settle the close calls. Extension experts say so often. In one 2024 Ask Extension case, an Oregon expert needed “to see a specimen to look at identifying features under a dissecting scope”.

For the best photo, put a few ants on white paper beside a ruler and shoot from the side in daylight. Use workers, not winged ants. If you still need a name, take a few ants to your county Extension office. The ants do not need to be alive, the Oregon expert told the asker, but they do need to be whole: “no squishing please!” You can also try our free photo bug identifier first.

Ant identification key: sort by size

Size is the fastest way to sort the common types of ants. Tiny ants are about 1/16 inch (2 mm), small ants about 1/8 inch (3 mm), medium ants 3/16 to 1/4 inch (4 to 7 mm), and large ants 1/4 inch (6 mm) or more. Find your size band, then read the first column of its table.

Each table puts the feature that separates the ants first. Also note whether every worker in a trail is the same size. Fire ants, carpenter ants and leafcutter ants come in mixed sizes in one colony, while most small house ants do not.

Tiny ants, 1/16 inch (2 mm) or less

Small ants, about 1/8 inch (3 mm)

Medium ants, 3/16 to 1/4 inch (4 to 7 mm)

Large ants, 1/4 inch (6 mm) and up

Sizes from UC IPM, Texas A&M, Ohio State, Illinois Public Health, Mississippi State and Ohio State BYGL. Where sources differ, the table gives the range they cover.

One size is worth a note. UC IPM, Ohio State and Texas A&M all give the thief ant as 1/32 inch, while DoMyOwn says 1/16 inch. Ohio State gives a range of 1/32 to 1/20 inch. That puts a thief ant at roughly 1 to 1.5 mm, and either way it is the smallest ant you are likely to find in a kitchen.

Common house ants: the kitchen and bathroom types

The types of ants that come into kitchens and bathrooms are about a dozen small species, most of them 1/16 to 1/8 inch (2 to 3 mm) long. They come in for sweets, grease and water. Odorous house, pavement, Argentine and pharaoh ants cause the most calls, and most of them nest outdoors and only forage inside.

Many people call any of these “sugar ants”, but that is a nickname, not a species. Our guide to what people mean by sugar ants sorts out which ant is usually behind the name. For bait choice and removal, our ant control guide matches each house ant to the bait it takes.

Odorous house ant

The odorous house ant (Tapinoma sessile) is a brown to black ant about 1/8 inch long. Crush one and it smells of rotten coconut, which settles the ID. It lives across the US, Texas A&M says, though it is rare in the southwestern deserts. DoMyOwn says it is not found in the Southeast, but iNaturalist has hundreds of confirmed records from North Carolina, Georgia and Alabama.

Argentine ant

The Argentine ant (Linepithema humile) is a dull brown ant about 1/8 inch long. It forms wide trails that run for yards, with many queens spread over many nests. UC IPM calls it the most common ant in and around California homes. On iNaturalist, California holds 10,646 of its 12,024 US records. PestWorld places it “mainly throughout the southeastern United States”, which misses where it is worst.

Pavement ant

The pavement ant is a dark brown to black ant, 1/8 to 3/16 inch long, with fine parallel grooves on its head and thorax. It pushes small piles of soil up through cracks in sidewalks, driveways and slabs. Illinois Public Health calls it “probably the most common ant in structures”. Its scientific name has changed to Tetramorium immigrans, so older guides call it T. caespitum.

Pharaoh ant

The pharaoh ant (Monomorium pharaonis) is a tiny yellow to reddish ant, about 1/16 inch long, with a darker tip on its abdomen. In most of the US it lives only in heated buildings. Never spray it. Texas A&M and Maryland Extension both warn that sprays and dusts make the colony split into new colonies, which is called budding. Baits are the method extension services recommend.

One Reddit user in r/pestcontrol reported a pest technician who insisted pharaoh ants “only live in hospitals”. That is wrong. They are well known in hospitals, but Texas A&M says they live in heated structures throughout the United States.

Little black ant

The little black ant (Monomorium minimum) is shiny jet black and about 1/16 inch long, with two nodes. Outdoors it leaves very small craters of fine soil in the lawn. It is native across the North and East and common in southern California, Texas A&M says. DoMyOwn limits it to southern California, Texas and Oklahoma, which leaves out most of its range.

Thief ant, also called the grease ant

The thief ant (Solenopsis molesta) is the smallest common house ant, yellow to light brown and about 1/32 to 1/16 inch long. Ohio State calls it the grease ant, because it feeds on grease, oils, cheese and meat rather than sweets. It gets its name from nesting near other ants and robbing their food and young. It belongs to the same genus as fire ants, Solenopsis, but it is far smaller.

Ghost ant

The ghost ant (Tapinoma melanocephalum) is under 1/16 inch long, with a dark head and thorax and a pale, almost clear abdomen and legs. The pale body is hard to see on a counter, which is where the name comes from. Outdoors it lives mainly in Florida and Hawaii. Farther north it turns up indoors, and Texas A&M lists finds in heated buildings as far away as Iowa and Oregon.

Crazy ants

Crazy ants are named for the way they run in fast, jerky zigzags instead of straight lines. The longhorn crazy ant is grayish black and about 1/8 inch, with very long legs and antennae. The tawny crazy ant, also about 1/8 inch but reddish brown, arrived near Houston in 2002. It now forms huge outdoor populations in Texas and Florida, and it does not sting, Texas A&M says.

Winter ant (small honey ant)

The winter ant (Prenolepis imparis), also called the small honey ant or false honey ant, is a shiny dark brown ant about 1/8 inch long. It handles cold better than other house ants. Illinois Public Health says it may be the first and the last ant seen each year, and it can vanish in summer heat. It is the third most photographed ant in the US on iNaturalist, with 21,553 confirmed records.

Big-headed ant

Big-headed ants (Pheidole) are reddish brown and 2.4 to 3.8 mm long, with two kinds of workers. The small workers look ordinary, but the large ones have a head far too big for the body. The native Pheidole dentata lives from Kansas to Virginia and south to Florida. An introduced species, the African big-headed ant, is one of the most reported ants in Hawaii.

White-footed ant

The white-footed ant is a black ant just over 1/8 inch long, with pale yellowish feet. It forms huge colonies with many egg-laying females, so it is hard to clear. Texas A&M lists it in South Florida, Hawaii and San Francisco. On iNaturalist, nearly all US records come from Florida.

Rover ant

Rover ants (Brachymyrmex) are about 1/16 inch long and range from black to pale blond. They neither bite nor sting, Texas A&M says, but they can turn up indoors in large numbers. Indoor problems usually go with moisture or rotting wood. Texas A&M also says rover ants are spreading in Texas.

Ants in wood and walls

Four types of ants nest in wood or wall voids: carpenter ants, acrobat ants, velvety tree ants and moisture ants such as the citronella ant. All of them prefer wood that is damp or already rotting. Finding one of them indoors usually points to a leak or a wet spot near the nest.

Carpenter ants

Carpenter ants (Camponotus) are the largest common house ants, 1/4 to 1/2 inch (6 to 13 mm) long, with one node and a smooth, evenly curved back. They are black, or red and black. They do not eat wood but dig nests in it. The eastern black carpenter ant is the most reported ant in the US on iNaturalist, with 36,276 confirmed records.

A colony has workers of many sizes, a clue Reddit users often point out. When one North Texas poster asked about ants “bigger than sugar ants”, with “some bigger than others”, the top answer was carpenter ants. Our carpenter ant guide covers the look-alikes and the damage, and our page on removing carpenter ants covers finding the nest.

Acrobat ants

Acrobat ants are about 1/8 inch long and lift a heart-shaped abdomen over their back when disturbed. They nest in damp wood and foam insulation, often around window frames. Our page on acrobat ants and the debris they leave explains how to tell them from carpenter ants by the waist.

Velvety tree ants

The velvety tree ant (Liometopum occidentale) is a western ant, 1/8 to 1/4 inch long, with a red thorax and a velvety black abdomen. It gives off a strong smell when crushed, UC IPM notes. It nests in dead limbs and stumps, and in California it sometimes moves into attics and walls where wood is damp.

Citronella and other moisture ants

The citronella ant, or larger yellow ant, is yellow to orange and up to 1/4 inch long. Crushed, it smells of lemon or citronella. Its winged swarmers often pour out of basement cracks in winter and spring, and people mistake them for termites. Illinois Public Health says baits do not work, because these ants feed only on honeydew from aphids on roots underground.

Pest companies call several yellow ants of this group “moisture ants”. They nest in soil and water-damaged wood, so a damp crawlspace or basement is the usual cause.

Ants in the lawn and yard

The yard ants people notice most are the mound builders: fire ants, harvester ants and field ants, plus pyramid ants and Texas leafcutter ants in the South. Mounds range from a tiny crater to Allegheny mound ant hills nearly 3 feet (1 m) high. Fire ants and harvester ants sting, so identify the mound first.

Fire ants

Fire ants are reddish brown, 1/16 to 1/4 inch long, with workers of mixed sizes in one colony. Their mound is loose soil with no single hole on top. In the US the main one is the red imported fire ant, found across the South and in parts of California. See our fire ant guide, with its state-by-state range, before you treat a mound.

Harvester ants

Harvester ants are large red to dark brown ants, 1/4 to 1/2 inch long, that clear a bare circle around one nest hole and collect seeds. They have a beard of long hairs under the head. Their sting is painful, so keep children and pets off the nest. Our harvester ant guide covers the kinds in Texas, the West and Florida.

Field ants and mound ants

Field ants (Formica) are medium ants, about 3/16 to 1/4 inch long, colored red, black, or red and black. They are often taken for carpenter ants, but their back is uneven, not smoothly curved. They have no sting. Instead, NC State Extension says, they pinch the skin and squirt formic acid into it, which can feel like a sting.

Most field ants build low mounds in lawns and flowerbeds. The Allegheny mound ant, with a rust-red head and thorax and a black abdomen, builds the big ones. Ohio State describes mounds “nearly three feet high by six feet in diameter”. These ants also inject formic acid into nearby plants, which kills the grass around the mound.

Pyramid ants

Pyramid ants (Dorymyrmex) are about 1/8 inch long, red and black, with a small cone-shaped bump on top of the thorax. They build a neat crater of soil in sunny, bare ground, often near other ants’ nests. In Florida, Buren’s pyramid ant is the fourth most reported ant on iNaturalist.

Texas leafcutter ants

The Texas leafcutter ant (Atta texana) is a rust brown, spiny ant whose workers range from 1/6 to 1/2 inch long. Workers carry cut pieces of leaves home, where they feed them to a fungus garden. Their nests can cover more than half an acre, with crater mounds. Texas A&M places them in central and eastern Texas and northwestern Louisiana, so yes, the US has leafcutter ants.

Twig ants

Twig ants (Pseudomyrmex gracilis) are slender, wasp-like ants about 5/16 to 2/5 inch (8 to 10 mm) long, with big eyes and an orange and dark body. They nest inside hollow twigs and stems and can sting. Terminix says they are “not commonly found” in the US. Yet iNaturalist has 7,089 confirmed US records, mostly from Florida and Texas.

Which types of ants sting?

In the US, five types of ants give a sting that matters: fire ants, harvester ants, the Asian needle ant, the little fire ant and twig ants. Most other house ants only bite, and some, such as rover ants, do neither. A sting can cause a severe allergic reaction in a sensitive person, so know which ants live near you.

The Asian needle ant

The Asian needle ant (Brachyponera chinensis) is a shiny black ant about 1/5 inch (5 mm) long, with orange-brown legs and one tall node. It lives under leaf litter, pine straw and rotting logs in shady yards. It does not trail like house ants. Mississippi State Extension says the sting can “potentially induce a life-threatening allergic reaction” in sensitive people, although this is rare.

It is spreading. iNaturalist has 3,568 confirmed US records from 24 states and Washington, DC, led by North Carolina, Georgia and Virginia. In the Mid-Atlantic and Upper South it now makes up 3.9% of all confirmed ant records, more than the pavement ant. Wear gloves when you move logs or mulch in those states.

Ants that bite but do not sting

Carpenter ants can give a hard pinch with their jaws but have no sting. Field ants pinch and then spray formic acid into the bite. Acrobat ants bite when the nest is opened, and Ohio State says they “bite fiercely”. Tawny crazy ants bite, but Texas A&M says the pain fades quickly. Odorous house, ghost and rover ants are not a bite risk.

One look-alike is worth knowing. A fuzzy red and black “ant” walking alone on bare ground is probably a velvet ant, which is a wingless wasp with a strong sting. Our page on the cow killer and other velvet ants shows how to tell.

Types of ants by color

Color narrows the list but rarely settles it, because about a dozen common types of ants are some shade of brown or black. Use it with size and place. Big black ants over 1/4 inch are usually carpenter ants, and tiny red ants in a southern lawn are usually fire ants. White “ants” are termites.

Are white ants real?

No. There is no white ant in the US. “White ants” is an old name for termites, as Illinois Public Health notes, and termites are not ants at all. A termite worker is soft and creamy white, with a thick waist and straight antennae. When a northern New Jersey Reddit user found “little white ant things” under rocks by a shed, the top answer was short: “They are indeed termites.”

The other white things in an ant nest are the young. The white “ant eggs” that workers carry when a nest is opened are mostly pupae, Illinois Public Health explains, since real ant eggs are almost too small to see. If you found white insects in wood, read our termite guide. If the problem is winged insects, see our guide to telling a flying ant from a termite.

What are the big red ants called?

It depends on where you live. In Texas and the West, a big red ant at a bare circle is a harvester ant. In the North, big red ants in a lawn mound are usually field ants. Red imported fire ants are small, not big, so a big red ant is rarely a fire ant. A big, fuzzy red and black “ant” is a velvet ant.

Red and black ants

Red and black ants are usually field ants or carpenter ants, and the back tells them apart. A field ant has a bumpy, uneven back. A carpenter ant has a smooth, evenly curved one. In the West, the velvety tree ant is also red and black, and pyramid ants are smaller red and black ants of bare ground.

Which ants live in my state?

The types of ants you meet depend on your region. Carpenter ants and the winter ant lead in the North and East, fire ants in Texas and the Deep South, and the Argentine ant in California, at 24% of confirmed records. We read the 792,099 US ant sightings on iNaturalist and built the table below from the expert-confirmed ones.

The first column lists the ants naturalists photograph most in each region. Next to it are the house ants that extension guides name for that area, and the last column flags the stinging ants to know there.

Percentages are each ant’s share of research-grade iNaturalist ant records in that region. They show what naturalists photograph, mostly outdoors, not how often each ant gets into homes. House ants from UC IPM, Texas A&M, Ohio State, Illinois Public Health and Maryland Extension.

Three findings stand out. First, the eastern black carpenter ant is the most reported ant in the country, with 36,276 confirmed records. Second, the red imported fire ant (22,008) and the winter ant (21,553) come next. Third, the Asian needle ant now outnumbers the pavement ant in records from the Mid-Atlantic and Upper South, a sign of how fast it has spread.

Season matters, too. Across the US, April holds 16.8% of ant sightings and May 15.3%, while December holds only 1.9%. So a trail in your kitchen in spring is normal timing. Ants indoors in midwinter usually mean a nest inside the heated house.

What are the three types of ants in a colony?

Every ant colony has three types of ants, called castes: workers, queens and males. Workers are wingless, sterile females that do all the work. Queens lay the eggs. Males have wings, mate once, and die soon after. Some species split the workers again into small and large sizes.

The ants you see on a trail are always workers. Queens and males only show up when they leave the nest in a mating flight, so a swarm of winged ants is the reproductive castes, not a new type of ant. Our guide to winged ants and what a swarm means covers that moment. After mating, a new queen sheds her wings and starts a colony. Our page on the queen ant and what finding one means explains how to spot her.

Worker sizes are the next clue. Carpenter ants, fire ants and leafcutter ants have workers of many sizes in one colony. Big-headed ants have just two: small workers and large ones with oversized heads, sometimes called soldiers. Honeypot ants go further. Some of their workers, called repletes, swell up with stored food and hang from the nest ceiling like living jars.

Other names for ants, and bugs called ants that are not ants

Many ants have two or three common names, and at least four “ants” are not ants at all. Grease ants are thief ants, electric ants are little fire ants, and sugar ants are a nickname for several house ants. White ants are termites, and velvet ants and blue ants are wasps.

The sugar ant name causes the most confusion. Google’s results mix the Australian banded sugar ant, which is large with an orange band, with tiny American kitchen ants. Our page on sugar ants in US kitchens sorts out which ant you probably have. The pissant name has a similar story. It started with European wood ants that squirt formic acid, and in the US it now means any small ant in the house.

Famous types of ants from around the world

Beyond the US house ants, a dozen kinds of ants are famous for one trait. The bullet ant has one of the most painful stings known. The Saharan silver ant is the fastest, at 855 mm (about 34 inches) per second. Army ants live on the move, and three of these famous groups live in the US.

Two of these come up in US searches often. Are there army ants in the US? Yes. Neivamyrmex nigrescens is the most widespread army ant in the country, and iNaturalist has confirmed records of it from more than a dozen states. Are there bullet ants in the US? No, though a large Texas ant is sometimes called the “Texas bullet ant”. Our bullet ant page explains the sting and the Texas look-alike.

What to do once you know your ant

Once you know which of the types of ants you have, the plan follows from it. Most sweet-eating house ants clear with cleaning, sealing and a bait on the trail within a few weeks. Pharaoh ants must never be sprayed. Carpenter ants mean damp wood, and outdoor field and pyramid ants can usually be left alone.

Start with what costs nothing: wipe up food, fix leaks, and seal the gaps the trail uses. If exclusion and sanitation are successful, insecticide treatments are not required. If you do use a bait or spray, choose an EPA-registered product whose label lists your ant and the place you will use it. The label is the law. Illinois Public Health puts it plainly: following the label is the applicator’s “legal responsibility”.

For a full plan, our guide to matching the bait to the ant covers sugar, protein and grease baits and where to put them. If you would rather start without pesticides, our page on natural ant repellents rates the home remedies honestly. Still not sure what you have? Our six checks for naming any bug help when it may not be an ant at all.

Pest control disclaimer. Photo-based identification can help, but it is not always perfect. For dangerous spiders, large infestations, or anything you are unsure about, contact a licensed pest control professional.