Although bats can see, in order to sense their surroundings in the darkness of night, most species use echolocation—determining the distance of an object by means of reflected sound. For example, some bats can distinguish a mosquito from a beetle by the speed of the insect’s wing beats.
Consider: Most bats produce pulses of sound in their larynx and project them through their mouth or nostrils. They use their large ears to detect the echoes produced when the sound waves rebound off objects. These echoes enable a bat to build a mental 3D image of its surroundings. The bat is able to determine the location, elevation, and distance of an object, even amid the noise clutter produced by other bats.
The bat’s echolocation needs to be extremely precise because an error of just one millisecond (one-thousandth of a second) could cause the bat to miss its target by as much as 17 centimeters (6.7 in). According to some researchers, a precision greater than one millisecond “appears impossible.” Yet, experiments suggest that bats have an echo time precision of 10 nanoseconds (100,000,000th of a second), enabling them to determine distances with an accuracy of a millimeter or even less!
Researchers have developed an electronic cane that uses echolocation to help blind people visualize their surroundings and avoid obstacles, including those at head height, such as a protruding tree branch. “A major inspiration for the work was knowledge of the impressive capabilities of echolocating bats,” state Brian Hoyle and Dean Waters, two of the designers of the so-called Batcane.
What do you think? Did the bat’s extraordinary echolocation ability evolve? Or was it designed?