Adam Li / NOAA/NMFS/SWFSC
Coen Elemans was waiting for his flight at Copenhagen Airport. Safety and passenger frequent announcements about the inter-cascade.
“They usually never say anything at this airport!” observed Elemans, a bioacoustic scientist at the University of Southern Denmark. “They are very vocal today.”
He says the airport is as good a place as any to hear the different ways they proclaim.
“I hear a lot of people talking,” he notes. “The most they use is what is called a command box.” This is our typical voice.
Then Elemans notes some music. It’s the thing where we most often hear our upper vocal register in pitch – falsetto.
We also have a lower panel, below the frequency range where we usually talk. Fry is vocal. In English, it is usually seen as an affect – that changes the feeling or attitude of what is said. Some people are known to him, like Kim Kardashian or Leonard Cohen. In other languages, such as Danish, Elemans says to change the meaning of words.
We produce all of these sounds—roasted vocals, chest voice, and falsetto—by passing air through our vocal cords into the larynx (the structure that allows air to pass from your throat to the rest of your respiratory system). And the vocal folds roll differently for each individual.
“In a vocal fry,” Elemans explains, “your vocal folds are generally relaxed, so they’re thick and heavy, and they vibrate at low frequencies.” And in the false record the longest and most tense are drawn. very deep And this at the highest frequency.
Elemanni wondered if something similar could be played in toothed whales (such as dolphins, orcas, and pilot whales), allowing them to produce different vocal sequences. Such sounds range from hissing to snapping (sounds we associate with Flipper) to echolocation clicks – pulsed sounds used for hunting prey. These clicks act “more or less like a flashlight,” says Elemans, “to scan their surroundings with highly focused beams.”
Toothed whales have a larynx, but it does not produce sound. Indeed, a “new structure” that is located in his nose that generates sounds – called the phonic lips”, says Elemans.
For decades, it has been difficult to observe phonics in action. No technology is up to the task and we are not yet able to observe whales in the depths where they often feed. But Elemans and colleagues developed several experiments to peck inside these animals. They report their findings in the latest journal Science.
They first lowered the endoscope into a few trained, captive dolphins and porpoises. You don’t need a small, tall camera; it was just that he could move his lips as fast as possible. “And we show their specific movements” [lips] while they make echolocation clicks, Elemans summarizes.
For the next experiment we need recently dead animals.
“Of course that’s difficult,” explains Elemans. “Usually when they die, they collapse. So it’s very difficult to study their physiology because we don’t have access to fresh tissue.”
But Elemans and others worked with marine mammal nets, especially in Germany, to collect harbor porpoises that had perished in the wild. Then they blew the air through their lips.
“What we have been able to demonstrate,” says Elemans, “is that these are phonic lips.” [are] it is not moved by muscle control like, for example, the purring of a cat. Rather, they become like the human voice through the flow. And this is really like that.
Additional experiments involving vocalization analysis and some CT scans suggested that toothed whales likely have separate vocal folds that generate numerous sounds, just like us.
On top of that, different registers have different functions. For example, through the sounds of wild animals in their habitats (by attaching acoustic tags to each animal) as well as to the hosts of porpoises and dolphins, the research team determined that it is the vocal fold that is responsible for echolocation in toothed whales. .
“The strength of this work,” says Kelly Benoit-Bird, Chair of Science at the Monterey Bay Aquarium Research Institute, “is that it combines field observations.” [toothed whale] Sounds and laboratory physiology studies combined with our understanding of marine mammal evolution provide a clear and complete picture of how dolphins produce a wide repertoire of sounds critical to their survival.”
Benoit-Bird, who was not involved in the study, points out the way researchers have investigated this scientific challenge from different angles.
“This work is all the enigmatic pieces, figuring out exactly how they fit together, filling in the gaps, finally making a clear picture of the dolphin’s sound production,” he says.
Agnese Lanzetti, an evolutionary biologist at the University of Birmingham, who was not part of the research, agreed.
“This is the very best research that shows how sounds are made mechanically,” he said, “and to prove that these sounds are generated from air.”
The physics of air plays a different role in the bodies of toothed whales than it does for us on land. When an animal like a sperm whale jumps a few thousand feet below the surface of the water, it collapses with a forced lung. But within the bony structure of the nose, air can pass through and power echolocation to move around.
“By moving all the air into their nostrils,” says Elemans, “these toothed whales can generate much higher pressures to propel the system. And with that, they can basically make the loudest sounds of any animal on the planet.”
And more importantly, they feed themselves in the process – turning vocal fry into fish fry.
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