They chew out the wood and use the tunnels as shelters in which to breed and from which to forage. Worker ants, the destructive form in the carpenter ant family, gnaw tunnels to house the colony. These ants do not use the wood as food, the way termites do. Carpenter ant galleries can be distinguished from termite galleries by the fact that the ant galleries are entirely clean, without debris, and have a sandpapered appearance. The harder summer wood layers are left creating a wafer-like effect.
Most damage occurs during warm months when carpenter ants are most active.
In heated buildings, ant activity may continue later in the fall and begin earlier in the spring than is usual with outdoor colonies. Flights of winged ants occur in spring and mid-summer. These ants are searching for suitable nest sites. The most common variety is black. Some varieties, of less importance, are partly red.