Although there are about 12,000 different ant species, the most common black ant is the carpenter ant, and it eats a variety of foods, including insects and plants. It is not uncommon for ants to eat household scraps, particularly sweet foods.
Ants will also eat other ants, dead insects and anything else they can gather during foraging. Food scout ants mark the trail to food using pheromones, which is why ants can sometimes be observed in a line, marching up to their meal. Ants can be cannibalistic and have been known to attack one another, especially if one ant is large and the other small.