When celebrities or singers use the lowest range of the voice, known as vocal fry, it tends to produce extreme reactions.
From Kim Kardashian to Britney Spears, this creaky, low-register dip in voice patterns either attracts or repels people, many of whom view it as an irritating affectation.
For some dolphins and whales, however, vocal fry serves a much more significant purpose: it allows them to communicate in the pressurized abyss of the deep ocean. Scientists have long understood that cetaceans had a special ability to continue producing sound — even at depths where the massive amounts of water pressure should make that impossible.
Now, they finally understand how. According to new research published in Science on March 2, specialized structures in the animals’ noses, called phonic lips, allow them to produce a large range of sounds with a minimal amount of air.
That’s necessary when you’re hunting for giant squid or other prey that live a kilometer below the ocean’s surface.
“One thousand meters down, you have one percent of the air you had at the surface,” Peter Madsen, a study co-author and zoophysiologist at Aarhus University in Denmark, told The New York Times. “To me, it’s always been super provocative to see a sperm whale or beaked whale or pilot whale dive deep, clicking happily, while having the knowledge in the back of my head that they’re supposed to use air for this.”
Finding the phonic lips
Marine biologists have long known about the special abilities of deep-sea diving mammals, also called toothed whales.
Dolphins, pilot whales, and sperm whales reach the sea’s sunless depths to find prey, sometimes working — and communicating — as a team. But figuring out just how they accomplish that hasn’t been easy.
Madsen and his colleagues tried a new strategy for their latest research. They inserted endoscopes in the nasal cavities of trained Atlantic bottlenose dolphins and harbor porpoises to record footage when the animals make their characteristic vocal fry.
That experiment proved that the sounds were coming from their nasal cavity, if not exactly what physical characteristic was producing it. To confirm that phonic lips were making the sounds, the next experiment involved dead porpoises (only beached or bycatch).
The scientists filmed the phonic lips while pushing air through the nasal complex. That allowed them to see the lips briefly separate and then collide, resulting in a tissue vibration that releases sound into the water.
