bio

Echolocation

A form of active sensing: instead of waiting for the world to send a signal, the animal emits a sound and reads the returning echoes to build a picture out of sound. Bats and dolphins emit high-frequency calls and decode the echoes for distance (from the time delay), speed (from the frequency shift - the Doppler effect), and size and texture (from the amplitude and tone of what returns). It is active because the animal generates its own probing signal, unlike the eye, which passively receives whatever light is already there.