Animal echolocation

Animal echolocation is an ability of some animals to locate objects by emitting sound waves and listening for the echo. This is used to detect obstacles, predators and prey. It is used by bats, dolphins and some whales. (Humans use the same technique in sonar for navigation of watercraft and medical ultrasound imaging to look inside the body.)

Besides emitting ultrasonic pulses, bats employ two kinds of saccades.

• Position (mechanical translation) saccades: moving the body, the head, or the ear flaps from side to side

Frequency saccades: varying the frequency depending on ambient conditions

Both kinds of saccades result in improvement of the spatial information (distance and location) and resolution.

For a comprehensive description of the echolation used by bats see microbat.

Dolphins emit a focussed beam of clicking sounds in the direction of their head; they receive the echo through the lower jar. When they approach the object of interest, they protect themselves against the louder echo by turning down the volume of the emitted sound. This is in contrast to sonar used by humans and bats, where the sensitivity of the sound detectors is turned down. See Bottlenose Dolphin for some more details.