The ant has a highly developed sense of smell. A team of researchers led by Lawrence Zwiebel of Vanderbilt University found that ants have about 400 receptors for different odors, which is more than any other type of insect. Ants perceive smells through their antennae.
Ants' sense of smell is used in communication through pheromones, which are chemical substances that trigger social responses. They use pheromones to mark trails from their nests to food and other resources. Another type of pheromone released by crushed ants serves as an alarm that attracts more ants and encourages attacking behavior. Pheromones also mark territorial boundaries and help identify an ant's task group. Some species of ants even use pheromones to confuse other ants, causing them to attack each other.