Carpenter Ant Biology and Habits

Carpenter Ants are indigenous to many parts of the world. They nest outside in dead, damp wood, building smooth, distinctive-looking nests. They remove wood to create passageways through wood grain to provide access to various nest areas known as galleries. Indoors, Carpenter Ants nest in any natural hollow, such as hollow-core doors, window sills, and wall voids.

Unlike Termites, Carpenter Ants do not eat wood; however, they damage wood, from hollowing out trees to damaging the materials used in the construction of buildings. Sometimes you can find their nesting location by observing the presence of frass, the very fine sawdust they leave behind when constructing nests.

Carpenter Ant Appearance

Scale : Small Ants to the larger Carpenter Ants

Carpenter Ants are large, from 1/4–3/8-inches long. They are dark brown to black, but some may have red or yellow coloration. The Black Carpenter Ant, Camponotus pennsylvanicus, in the east and C. modoc in the west are the most thoroughly studied species in the United States. Other species of Camponotus are distributed throughout the country. The queens are slightly bigger than the workers. The workers of an established colony vary in size. The most common variety of Carpenter Ant is large and black, but the Florida Carpenter Ant is smaller and ranges in color from yellow, red, brown to black.

Black Carpenter Ant

black carpenter ant

Florida Carpenter Ant

Florida Carpenter Ant

Eastern United States:

(Camponotus pennsylvanicus)

Color: All black

Workers: 1/4–1/2-inch in size

Queen: Large, over 1/2-inch in size

Swarming: Colony matures in 3–4 years,
swarming occurs in late spring–summer

Distribution: Mid West to Eastern States

Western United States:

(Camponotus modoc) (Camponotus vicinus)

Color: Black Body, red dark legs

Workers: 1/5–1/2-inch in size, but variable

Queen: Large, over 1/2-inch in size

Swarming: Occurs in late spring–summer.

Colony size: Up to 15,000 workers

Distribution: Western US States

Nests: Generally excavates in decayed or damaged wood.
Creates smooth tunnels adn galleries.
They can compromise structural integrity
by expanding into sound wood.
Nests may be found in dead trees and stumps outside.

black carpenter ant
Univ. of Nebraska (click on image to enlarge)

(Cabdominalis floridanus)

Color: Red head, black abdomen, thorax, and legs

Workers: Smaller, 3/16–3/8-inches in size

Queen: Large, over 1/2-inch in size

Swarming: Unmated swarmers in satellite colonies

Distribution: Florida and southeast U.S.

Colony size: Up to 3,500 workers.

Nests: Seeks to nest in existing voids or excavates soft woods
that are rotten and styrofoam.

florida carpenter ant
Univ. Of Florida (click on image to enlarge)

Field Ant-Not to be confused with the Carpenter Ant


Univ. of Nebraska (click on image to enlarge)

The Field Ant (Formica)may be identified as a Carpenter Ant. Both Carpenter Ants and Field Ants have one node or a one-segmented waist. The Field Ants have an uneven thorax, and the Carpenter Ants have an evenly rounded thorax. The Field Ant may be found throughout the US.

Field Ants may come inside to forage, but do not establish nests inside like the Carpenter Ant. They nest in soil or decayed logs and construct their nest from grass stems, twigs, pine needles, etc., forming a mound. They form low profile mounds in the yard. Their mounds can reach a foot or more in diameter. If the mound is disturbed, they may aggressively swarm out ant bite the intruder. The bite may sting.

They are commonly noticed during the fall months as they swarm from underground to new locations to establish new colonies. Use an ant bait granular around the mound like Maxforce Complete Ant Bait.

Carpenter Ant Diet

Outdoors, Carpenter Ants feed on protein-based foods (such as living and dead insects) and sweet-based foods (such as the honeydew produced by aphids and certain scale insects). Indoors, Carpenter Ants feed on meat and fats, and any sweet food such as syrups and jellies.

Most foraging is done at night between sunset and midnight during the spring and summer months. Sometimes workers travel up to 100 yards from a nest in search of food.

Carpenter Ant Habits

Carpenter Ants are nocturnal. They prefer to hollow out their nests in softened wood, such as moist or partially decayed wood. Their nests are called galleries. These galleries are clean and have a sandpaper appearance.

In comparison, Termite galleries are rough looking. Wood that has been damaged by Carpenter Ants contain no mud-like material, as is the case with Termites.

Florida Carpenter Ant nests are commonly found indoors in such places as the moist, hollow wall void behind dishwashers. Nests are usually found in areas where water leakage could occur, such as around bathtubs, sinks, roof leaks, poorly-flashed chimneys, or poorly sealed windows or door frames. Outdoor nests are found in places like tree stumps, hollow logs, fence posts, or dead portions of standing trees. However, these persistent creatures have even been known to build nests in cracks and crevices of sound wood.

Carpenter Ants may establish nests in a number of different locations. It is important to understand that you can have both inside and outside nests. Carpenter Ants construct two different kinds of nests: parent and satellite colonies. Parent colonies, when mature, contain an egg-laying queen, a brood, and 2,000 or more worker Ants. Satellite colonies may have large numbers of worker Ants, but contain no queen, eggs or larvae. For example, the Ants found in your home may have originated from parent nests outdoors,
perhaps in a tree stump, timber or woodpile, or from one or more satellite nests hidden behind a wall in the kitchen or bathroom, or perhaps from wood dampened by a roof leak in the attic. Although large Carpenter Ant colonies can cause structural damage,
the damage is not normally as serious as Termite damage.

Often, the Ants you see inside your home are simply foraging for food, and you may not see large numbers of them. Foraging workers can travel 100 yards from nest to food and can be found wandering throughout your house.