Thaindian News

Washington, Sep 14 (IANS) The way fruit bats use sonar to navigate through complex environments is more advanced than first thought.

A study examines Egyptian fruit bats which use echolocation to orient inside their caves and to find fruit hidden in the branches of trees.

Their high-frequency clicks from a sonar beam that spreads across a fan-shaped area, and the returning echoes allow them to locate and identify objects in that region, the journal Public Library of Science Biology reports.

The research team, led by Nachum Ulanovsky of the Weizmann Institute, Israel, and Cynthia Moss, University of Maryland, US, reports that these bats adapt to environmental complexity using two tactics, according to a University of Maryland statement.

First, they alter the width of their sonar beam, similar to the way humans can adjust their spotlight of attention in order to spot, for example, a friend in a crowded room.

Second, they modify the intensity of their emissions. “The work presented here reveals a new parameter under adaptive control in bat echolocation,” Ulanovsky says.

Ulanovsky and his team trained Egyptian fruit bats to locate and land on a mango-sized plastic sphere placed in various locations in a large, dark room equipped with an array of 20 microphones that recorded vocalisations.

Although these new findings may be unique to Egyptian fruit bats because of their rapid tongue movements, Ulanovsky explains that their results “suggest that active sensing of space by animals can be much more sophisticated than previously thought”.

“They call for a re-examination of current theories of spatial orientation and perception,” he adds.