Bats are the death metal singers of the animal world, research shows

It's been known for a long time that the comedian has a penchant for bats. The mammals seem to be fans of his.

Scientists have discovered that bats have a vocal range that surpasses that of most humans, and that they have death metal growls.

Ultrasonic chirps are used to echolocate flying insects in the dark, but they also communicate with each other at low frequencies.

The production of sound from ventricular folds, which sit just above the vocal cords, is rare in the animal kingdom, with bats now becoming members of an exclusive club populated almost entirely by death metal and Tuvan throat singers.

Prof Coen Elemans said that if you listen to a bat colony in the summer you can hear the calls. They make the calls when they are angry with each other and when they join a colony.

When the scientists studied how bats produce high frequencies for echolocation, the finding came about. The researchers noticed the ventricular folds vibrating at low frequencies when they took high speed video of bat vocal cords.

Death metal singing and Tuvan throat singing are the only uses for these vocal folds in humans. Death metal grunting has the same effect as the oscillations becoming irregular and rough.

The Black Sabbath singer bit the head off a bat during a performance in 1982. He thought the bat was a toy until he bit down on it. The animal may have died when it was thrown on stage.

Only a few humans have a vocal range of five octaves. The mystery of bats achieving seven is solved by the Danes.

Elemans said that the vocal membranes used for echolocating have a range of three to four vowels.

Bats have evolved a highly specialized larynx that's perfect for producing sound waves up to 120 kilohertz. These calls act like a flashlight and can be used to locate flying insects. The chirps travel only a few metres and the animals need another way to communicate.

Bats need to do something different in order to have a range for communication because of the severe selection on echolocation calls. The study is in a journal.