A new study out of Denmark shows that bats use different parts of their voice box to make noise in a range that is “tremendous” compared with other mammals. Most humans can hit three to four octaves — bats have nearly double that range. The study, published in the PLOS Biology journal on Tuesday, reveals new details about how the winged animals communicate.
Elite singers, such as Carey, can reach more octaves than the typical person. The “All I Want For Christmas Is You” singer is known for a five-octave range that allows her to reach high notes, such as those in her 1991 hit “Emotions,” making the song a challenge for many singers to replicate. Legendary artist Prince also had an atypical vocal range, with some speculating that he may have sung notes across six octaves.
But bats? The sounds they make can span seven octaves, the study shows, surpassing both Carey and Prince.
For the first time, researchers from the University of Southern Denmark caught on video how the mammals make sound — a process that involved using the voice boxes of eight Daubenton’s bats, medium-sized bats with short ears that are found across Europe and Asia.
To do this, the team used cameras that could capture high speeds to track movement in the bats’ voice boxes, said Coen Elemans, a biology professor who led the Danish research team.
Like dolphins and toothed whales, bats use echolocation, a navigation technique based on how sounds are reflected. The study captured the varying sounds bats use while echolocating, including a fast, high-frequency sound that researchers believe the creatures use while flying to find and catch insects.
To observe that sound, the Danish team created a setup that blew air through each bat’s voice box and recorded the experiment to see what parts vibrated.
But the process led them to another discovery.
The bats made low-frequency sounds through their false vocal folds, a part of the voice box not typically used by humans to speak or sing, Elemans said.
The people who do use them? Death metal growlers and Mongolian throat singers, the research team said in a news release.
The howls and growls of metal music can damage singers’ vocal cords if they use improper technique and fail to protect their voices. Matt Heafy, lead singer of the heavy metal band Trivium, had to learn proper techniques and routines after he blew out his voice about eight years ago, Loudwire reported.
While bats can make similar growling sounds, it’s still unclear what they are trying to communicate. That probably will take more research to answer, according to the Danish team.
“Some seem aggressive, some may be an expression of annoyance, and some may have a very different function,” Lasse Jakobsen, a co-author of the study, said in the news release. “We don’t know yet.”