The Chiroptera, commonly called bats, fascinate as much as they frighten. These animals with a complex social organization continue to intrigue researchers. A Danish study published Tuesday in the journal Plos Biology and relayed by the magazine New Scientist points out that bats “grunt” like death metal singers or Mongolian throat singers.
To understand these vocal properties, scientists have hooked a microphone to dissected bat larynxes and observed them under the microscope. Then, they circulated air in it as if it was coming out of one of them. This airflow produced sounds that originated from two different laryngeal structures. According to their results, the extreme highs and lows would extend three or four octaves more than in the average human. This is the first project to have filmed the vocal membranes of Chiroptera. To show the movement produced by vibrations“we had to film at extremely high frequencies [avec une caméra de haute vitesse], up to 250,000 frames per second. We have observed many adaptations in the larynx, which we believe are responsible for the ability of bats to rapidly emit calls at very high frequency, in order to be able to catch insects in flight,” says the first author of the study, Jonas Hakansson.
These nocturnal animals also have their own built-in tracking system: echolocation. A sixth sense, even a “acoustic vision”, which allows them to move without using their eyes. “A bat can determine the shape, size and texture of objects echoing it within milliseconds,” details Lasse Jakobsen, co-author of the study.
An artists voice
The team discovered that these high-frequency echolocation cries are produced by thin, translucent vocal membranes that rest on the vocal cords. The lower frequency squeaks come from vocal folds. These “creases” are also present in humans “but they are rarely used, never for normal human speech and singing,” explains Coen Elmans, professor of biology at the University of Southern Denmark, in a statement attached to the study. Only death metal growlers and throat singers from a few cultures in the world use their vocal folds like bats.
These mammals are true artists whose vocal abilities would exceed those of Mariah Carey. According to the Danish team, the vocal range “normal” of a bat spans seven octaves. “It’s amazing. Most mammals have a litter of three or four [octaves], and humans have about three. Some human singers can reach a litter of four or five, but they are very few. The best known examples are Mariah Carey, Axel Rose and Prince. And it turns out bats go beyond that by using different structures in their larynx.” raves Professor Elmans. Now you can imagine the concerts Batman attends when he’s not saving Gotham City.