Bats can fly mute to avoid jamming natural sonar signals among their species

August 27th, 2008 - 12:56 pm ICT by ANI  

National Geographic

Washington, August 27 (ANI): A new research has indicated that by shutting down their natural sonar, some bats can prevent crossed signals with others of their species, while flying.

Bats measure distances, dodge objects, and locate prey by listening to their own sound signals bounce off objects.

Flying mute could signal active cooperation among the mammals, but scientists dont know for sure.

According to a report in National Geographic News, the researchers made the surprising discovery while tracking how groups of captive big brown bats adjusted their signals as they pursued prey.

Some simply shut down their sonar for up to 800 milliseconds, according to Cynthia Moss, of the University of Marylands Auditory Neuroethology Laboratory, and colleagues.

To humans that sounds very short, but bats operate on a completely different timescale, Moss explained.

The time from detection of an insect to capture is often less than a second. Typically, when they approach an insect, they wait only 20 to 50 milliseconds between sounds. So, if they go silent for 600 or 800 milliseconds, thats a long time for them, she added.

Biologist Richard Holland of the University of Leeds, UK, said that the exciting finding appears to show bats using passive listening to hear the calls of other bats.

There has been a lot of speculation that they could do this, but I think this is possibly the first demonstration that they are listening to other animals calls in addition to their own, he said.

So far, scientists have only theories to explain the behavior.

When one bat went silent, it was typically trailing another bat. So, it was in a good position to listen to the echoes and vocalizations produced by the leading bat, Moss said. But whether they are cooperating is an open question, she added.

According to Moss, though bats without sonar are flying deaf in a sense, they likely have ways to compensate.

In the wild, they could rely on spatial memory in familiar surroundings, and they could also use vision in moonlight that would aid them in locating obstacles, she said. (ANI)

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