Carpenter ants are large (¼–1 in) ants indigenous to many parts of the world. They prefer dead, damp wood in which to build nests. Sometimes carpenter ants will hollow out sections of trees. The most likely species to be infesting a house in the United States is the Black carpenter ant, Camponotus pennsylvanicus. However, there are over a thousand other species in the genus Camponotus.

Symbionts
All ants in this genus, and also some related genera, possess an obligate bacterial endosymbiont called Blochmannia.[1] This bacterium has a small genome, and retains genes to biosynthesize essential amino acids and other nutrients. This suggests the bacterium plays a role in ant nutrition. Many Camponotus species are also infected with Wolbachia, another endosymbiont that is widespread across insect groups.

Habitat
Carpenter ant species reside both outdoors and indoors in moist, decaying or hollow wood. They cut "galleries" into the wood grain to provide passageways for movement from section to section of the nest.

As Pests
Carpenter ants can damage wood used in the construction of buildings. They can leave a sawdust like material behind that provides clues to nesting location.

Exploding ants
In at least nine Southeast Asian species of the Cylindricus complex, such as Camponotus saundersi, workers feature greatly enlarged mandibular glands. They can release their contents suicidally by rupturing the intersegmental membrane of the gaster, resulting in a spray of toxic substance from the head, which gave these species the common name "exploding ants"
Its defensive behaviors include self-destruction by autothysis. Two oversized, poison-filled mandibular glands run the entire length of the ant's body. When combat takes a turn for the worse, the ant violently contracts its abdominal muscles to rupture its body and spray poison or glue in all directions.[3][4] The ant has an enormously enlarged mandibular (abdomen) gland, many times the size of a normal ant, which produces the glue. The glue bursts out and entangles and immobilizes all nearby victims.
The termite, Globitermes sulphureus has a similar defensive mechanism.