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Bats equipped with mini computers reveal echo hunting techniques

Scientists equipped wild greater mouse-eared bats with a tiny computer to hear how they go about seeking prey.
Scientists equipped wild greater mouse-eared bats with a tiny computer to hear how they go about seeking prey. Scientists equipped wild greater mouse-eared bats with a tiny computer to hear how they go about seeking prey.

Bats are able to fine-tune minute prey echo sounds similar to a whisper when hunting, according to new research.

Scientists were able to hear how the flying creatures use prey echoes by strapping tiny computers to some wild greater mouse-eared bats in Bulgaria.

The recordings captured echolocation calls, when bats use sound to navigate the movement of each bat in three dimensions, as well as the echoes that bounce back from their environment.

Lead author Dr Laura Stidsholt, from Denmark’s Aarhus University, said: “We experienced the world through the ears of the bats by recording their echoes directly on-board while they were hunting for insects at night.

“We wanted to use the tags to find out how bats control what they ‘see’ when they hunt tiny insects on the wing on superfast timescales.

“We used the sound recordings to find and track echoes from prey and vegetation, and to our surprise we found that the bats are guided by extremely weak prey echoes that would be like a whisper to us.”

Scientists’ research suggests that hunting bats narrow their sensory volumes by more than a thousand times to only focus on the prey, thereby reducing the clutter from other echoes.

According to co-author Dr Holger Goerlitz, from Germany’s Max Planck Institute of Ornithology, it’s “like an acoustic version of a tunnel vision that briefly makes their world much simpler”.

He added: “The weak prey echoes might therefore be a consequence of the small sensory volumes shaped to hunt close to background clutter.”

The research is published in the Science Advances journal.