An Army Ant colony, which can consist of more than 1,000,000 members, is almost a life form itself. Unlike many other insects, Army Ants migrate. This migration is a necessity, as they otherwise would starve. Army Ants will eat almost anything in their paths, and an ant colony can eat as many as 50,000 insects per day.
Army Ants do not limit their feeding to insects. They are so powerful that they are capable of bringing down much larger animals, including lizards, birds, pigs, and even horses. Although the larger animals can usually escape the hungry ants, if hurt or sleeping, they are more susceptible to being eaten. Because of the Army Ant's voracious appetite, they must constantly migrate to find new sources of food. About 150 different species of Army Ants migrate around North, Central and South America. The colonies are not made up entirely of ants. Other species of insects have been known to travel with Army Ant colonies. As many as 100 species of interlopers have been identified and there are most likely more.
Army Ants live in very hierarchical societies. The colonies include the queen, her eggs, soldier and workers. Because they are migratory, they must make temporary nests as they travel. Their manner of forming a nest is quite interesting: it is made up of the ants themselves. They form walls by clamping onto one another with their jaws, or mandibles, and their claws. They then attach themselves to a log or other hard surface and enclose the queen and her brood. The queen is at the top of the hierarchy. Her sole purpose is to lay eggs, which she does every day. Soldiers are responsible for defense, and workers either forage for food or tend the queen's eggs, depending on their size. The soldiers are male and the workers are all sterile females. The Army Ants' bodies consist of a head, thorax and abdomen. They have two jaws, more commonly known as mandibles. However, Army Ants can only swallow liquids. Unlike most other insects, Army Ants have single eyes instead of compound eyes. Their eyes do not do them much good, however. They are blind. Instead, they use their antennae to find food and figure out where they are going. The average Army Ant is 8 to 12 milimeters in length.
The name "Army Ant" comes from not only the migratory nature of Army Ants but also because of how the colonies are set up. While migrating, a colony of Army Ants will raid other colonies and take slaves. Like many armies, they march at night and stop to rest in daylight. Although Army Ants can kill very large animals, humans value them. In the Southern United States, villages will gladly surrender their homes to the ants, as they are natural pesticides. People can leave their houses, come home a few days later and find their homes entirely insect free.