Fastest muscle in a mammal

A study of the hunting behaviour and associated anatomy of Daubenton’s bats (Myotis daubentonii) revealed that superfast muscles in their throats can move (i.e., contract and relax) up to 200 times per second (200 Hertz). That's once every five milliseconds or, to put it in context, around 20 times faster than the muscles that control blinking in the human eye (the fastest human muscles). This state of high oscillation in the larynx produces a barrage of calls – referred to as “terminal buzz” – which are used to home in on prey through echolocation in the final stages of a hunt. The results were published in the journal Science on 30 September 2011.

The same research found that the bats’ hearing is also more advanced than previously thought, with an ability to hear and distinguish an estimated 400 echoes per second.

The study was conducted by the University of Southern Denmark (Denmark) and the University of Pennsylvania (USA), led by Associate Professor Coen Elemans of the University of Southern Denmark.

While this was the first example of superfast muscles in a mammal, this physiological feature has previously been encountered in other animals, such as the tails of rattlesnakes and the vocal apparatuses of songbirds. Subsequent research suggests that there could be a cut-off point for super-fast muscles among vertebrates of 250 Hertz, as documented in the journal eLife on 22 November 2017.

Researchers postulate that along with evolving the ability to fly, and to echolocate flying insects in low-light conditions, the “terminal buzz” (enabled by the superfast muscle in their throats) also played a key part in the success of aerial hawking bats when they began to emerge c. 50 million years ago.