Common species are dark, often black.
Carpenter ants cannot sting but if handled can inflict a painful bite with their powerful jaws. They emit a noxious excretion of formic acid when disturbed. Carpenter ants enter buildings in search of food and may construct nests containing several thousand individuals somewhere within the building. Nests constructed indoors may be satellite colonies of a larger nest located outside near the building, usually in trees. Although ants do not eat wood, they bore into wood to make their nests, which consist of extensive networks of galleries usually begun in areas soft from decay.