A colony of carpenter ants contains workers of several sizes. The smallest workers are usually less than 1/8″ long. The largest workers can be more than 0.5″ long.
The carpenter ants that invade homes usually come for food or water. When the workers find a source of food or water (or both), they often make a nest nearby. The carpenter ant workers frequently nest in hollow spaces like wall voids around doors or windows and even inside hollow doors. If the workers find wood that is damp and decaying, they hollow it out to use as a nesting site.
Carpenter ants are usually active at night and on cloudy days, so they can often become established in homes before the homeowners notice them. At first, a homeowner might only see a few ants. However, if the homeowner finds a nest, he or she may come face-to-face with hundreds of large ants. If the homeowner disturbs the nest, he or she may be bitten by some of the ants.
Carpenter ants do not sting, but their jaws, called mandibles, are very strong. The large workers can deliver a painful bite. The Florida carpenter ant, Camponotus floridanus (Buckley) has such a fierce bite that many people call it the “bulldog ant”.
Many years ago, medical practitioners used carpenter ants to “stitch up” wounds. They held the ant over the wound until it closed its jaws. Then the head of the ant was removed. This left the ant's jaws firmly clamped in the skin like a staple. The ant's jaws held the wound closed while it healed.
Carpenter ants, like other ants, have glands in their mandibles. The chemicals that they produce are used for defense and for alarm signals. If the carpenter ants break the skin when they bite a human, it is very possible that these chemicals could be irritating. Some people may be allergic to these chemicals. If carpenter ants bite a person, he or she should be watched carefully. If the victim shows signs of allergic symptoms, a doctor should be consulted.