Carpenter ants are among the largest ants in the United States, ranging from 3.4 to 13 mm long. The most common color is black, but some species have reddish or yellowish coloration. Workers have large mandibles. Carpenter ants reside both outdoors and indoors in moist, decaying or hollow wood. They cut galleries into the wood grain to form their nests and provide passageways for movement from section to section of the nest. This activity produces wood shavings mixed with parts of dead ants which provide clues to nesting locations. Carpenter ants do not eat wood, but they will feed on a variety of food people eat—particularly sweets and meats.
They will also feed on other insects. Queen lays 9 to 16 eggs the first year and may live up to 25 years. Eggs complete their life cycle in about 6 to 12 weeks. Carpenter ant workers and swarmers (winged ants) are the most likely sign homeowners observe. The workers may be observed foraging for food. Swarmers usually are produced when a colony matures and is ready to form new colonies. These winged individuals often indicate a well-established colony. An additional sign of carpenter ant activity is the debris they produce from tunnelling in the wood. Rough wood shavings mixed with parts of dead ants from the colony indicate carpenter ant nesting activity. A final sign may be the “rustling” sound sometimes heard as the ants go about their activity in the home’s wood.