Echolocation is an active perceptual system, used by some animals to localize and identify objects in complete darkness. The active component of echolocation is the animal's production of sounds that reflect from objects in the environment, and perception arises from listening to the features of these echoes. Echolocation has been documented in bats, marine mammals, some species of nocturnal birds, and in blind or blindfolded humans to a limited extent. This entry describes echolocation signals, perception by echolocation, and neural mechanisms for echo processing.

Consider an echolocating bat hunting insects in the night sky. Light levels are low, and the bat need not rely at all on its vision. Obstacles are present, but the bat dodges branches and telephone wires with ease. As the animal flies, ...