Bats Use Superfast Muscles to Create High-Pitched Buzz

Bats are known to be able to create a high-speed buzz to help navigate and search for prey in the dark. Until now, researchers had no idea how they managed to create that buzz.

Researchers from the University of Southern Denmark and University of Pennsylvania suggest that the ability is made possible by a physical trait never before seen in mammals - the so-called “superfast” muscles.

We discovered that Daubenton's bat (found throughout Eurasia) controls its echolocation calls with the fastest-contracting muscle type described, Coen Elemans, of the University of Southern Denmark and the study's lead author, said in a press release.

“This indicates that the kind of superfast muscles are much more widespread in the animal kingdom than we went and thought,” he added.

Superfast muscles are capable of contraction about a 100 times faster than muscles in the body and as much as 20 times faster than the fastest human muscles - those that control eye movement.

The new study, published in the latest issue of the journal Science, put bats on a short list of animals that possess these rare superfast muscles. These high-performance muscles were previously only believed to have been found in the sound-producing organs of rattlesnakes and a few species of fish.

But recently we also found them in birds who use them to sing their beautiful songs. And now we have discovered them in mammals for the first time suggesting that these muscles – once thought extraordinary – are more common than previously believed,” Elemans said.

The bat can increase its echolocation call rate to 190 calls per second, in the dark, to form a terminal buzz, just moments before capturing its target.

It was unknown how bats are able to produce calls so quickly. We figured that this rate would be limited by the bats ability either to process the returning echoes or produce the calls themselves,” explains John Ratcliffe, a senior author on the study.

Our data suggests that bats could theoretically produce calls much faster - up to 400 calls a second - before the returning echoes would become confusing to the bat, said Ratcliffe.

Ratcliffe concludes that it is actually the muscles that limit the maximum call rate during the buzz and believes this ability allows the bats to better track the often erratic movements of insects in the dark.