Smithsonian.com

An Egyptian fruit bat aims for an apple (image courtesy of Yossi Yovel)

The Egyptian fruit bat (Rousettus aegyptiacus) pinpoints its meal with its sonar not by aiming in front but by “looking” off from side to side, according to a study in a recent issue of Science.

With sonar, a bat (or whale or submarine) will emit a sound that is reflected off nearby objects. Those sound waves are altered by the objects, and the bat can use those changes to gain information about what the object is and its distance and direction. There are two strategies for sonar detection: A sonar beam that is sent directly forward, which returns more information overall, or a signal that hits objects on an angle, which can give more precise information.

Mathematically, strategy number two is the best strategy, and that is the one that Egyptian fruit bats use. The researchers suggest that such a strategy tradeoff may be involved in other detection methods, such as smelling, vision and hearing.

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