The best way to track a moving object with a flashlight might be to aim it to one side, catching the object in the edge of the beam rather than the center – just ask a bat.

New research at Israel’s Weizmann Institute of Science reveals that bats skew their sonar or echolocation beams off-center when they want to locate an object. The research, which recently appeared in the journal Science, shows that this strategy is the most efficient for locating objects.

The Egyptian fruit bats studied by Dr. Nachum Ulanovsky and postdoctoral fellow Dr. Yossi Yovel of the Institute’s Neurobiology Department threw their sound beams to alternate sides of a sphere, just where a mathematical formula for sonar sensing predicted they would be most effective. As the sphere was easily detectable, the bat’s optimal strategy was one of localization.

The scientists also tested a situation in which detection was needed as well as localization, and found that as the bats approached their target they began to narrow their sweep and aim the beams more or less directly toward the sphere, thus proving that bats can choose the best echolocation strategy.

A string of special microphones traced the bats’ sound waves, while two infrared video cameras tracked their flight patterns.