Bat mouths are already pretty much completely awesome, thanks to their amazing echolocation abilities. So this almost seems like overkill: bats are the first known mammals to possess superfast muscles, moving a hundred times faster than the average human muscle.
It all goes back to echolocation - as bats close in on their prey, they let out a super-concentrated sonic burst of up to 190 calls per second. This is known as the terminal buzz, and as you can probably guess, you don't want to be on the receiving end of it if you're bat prey. It's a remarkable ability, but it's only now that scientists have actually worked out what allows bats to make such calls.
It turns outs that the terminal buzz is created by superfast muscles unlike anything ever seen in any other mammal. A few reptiles, birds, and fish possess similar muscles, each capable of contracting at least a hundred times per second, but this is unheard of among mammals. Most muscles in the human body only contract about once per second, and even the very fastest muscles in our bodies - those that control our eyes - still only operate twenty times slower than these bat muscles.
Coen Elemans and his team at the University of Southern Denmark and the University of Pennsylvania studied how the Eurasian species Daubenton's bat created the terminal buzz. They quickly discovered that the buzz is impossible to create in normal vertebrate skeletal muscle. The bat's laryngeal muscles represent a unique adaptation that allows them to contract 200 times per second, though it appears that in practice they only need to contract half that fast to create the terminal buzz.
We have discovered them in mammals for the first time, suggesting that these muscles – once thought extraordinary – are more common than previously believed. We determined the power the muscles can deliver, much like how you measure a car's performance. We were surprised to see that bats have the superfast muscle type and can power movements up to 190 Herz (times per second), but also that it is actually the muscles that limit the maximum call rate during the buzz.
That's right - bats are using one-of-a-kind superfast muscles unknown in any other mammal...and they still could go faster if they wanted to. Fellow researcher John Ratcliffe estimates bats could actually get all the way up to 400 calls per second before the sound would start to confuse their brains. Even then, it's possible the muscles could still go faster...but, you know, that would quite literally blow the bat's mind.
So, these are pretty remarkable muscles, and the fact that they've now been found in one mammal might mean that they're actually more common than we thought. Either way, these superfast muscles are likely the key to bats' remarkable success as the world's only flying mammal, as Elemans explains:
Before the bats evolved more than 50 million years ago, the night skies were full of flying moths and other insects. Next to flight and echolocation, we now think that it is the buzzes powered by superfast muscle that allowed bats to better track the often erratic movements of insects in the dark and made them so successful.