1: Biosonar Signals		1 of 2

A biosonar signal is a short sound used by an animal to probe its environment with its sonar system (have you looked at the introductory demonstration?). All echolocating animals produce these short pulses of sound. Most of the sounds are ultrasonic, so we can't hear them (have you seen the ultrasound demonstration?). Clicks, chirps, squeaks, calls and cries are all words used to describe the animals' sonar signals, but because most are ultrasonic, we don't know what they really sound like.

In any case, it is unlikely that animals using biosonar listen to echoes in the same way that we would do. Instead, they receive and analyse them with their sonar receivers, to form images. What is critically important to the animal is how its sounds perform as sonar signals. Everything that animals perceive about their environment by means of biosonar is down to differences between the sonar signal that they transmit, and the copies of that signal that return as echoes.