The most common large black ant problem in a home is caused by carpenter ants. These insects get their name by their preferred living space--namely damp, rotting wood. While carpenter ants do not eat the wood, they do bore into it to make space for their colony. This behavior is very destructive to the wood in your walls, and makes finding the ant colony vital as soon as there are signs of infestation. Specifically watch for small piles of sawdust on the floor inside or outside the home. Sometimes termites might be mistaken for large black (or carpenter) ants. To know which is which note that carpenter ants have narrower waists and bent antennae compared to termites. Also termites tend to be stealthier. They don't like to come out into the light whereas carpenter ants will march brazenly through your home, very often during the night looking for sources of sugar and protein.