Army ant attacks and eats a worker ant gathering around a clump of arequipe (dulce de leche) in my garden. . . Fun facts: army ants feed on other ants and insects, including beetles many times their size. They can even feed on some smaller animals like frogs, snakes and lizards. The only defense against an army ant attack is staying still. This is because army ants are nearly blind, so they rely on light and darkness from movement to detect prey.