When hunting for their prey, whales find it useful to sing like Mick Jagger and Britney Spears to help them locate, track and catch their quarry, according to a study.
In an extraordinary discovery, scientists have found that sperm whales, dolphins, porpoises and other toothed cetaceans employ a similar vocal technique to humans, known as ‘vocal fry’, which has been crucial to their evolution and survival.
Named because it sounds like sizzling bacon, vocal fry is most commonly associated with the drawling speaking voices of US celebrities such as Kim Kardashian, Scarlet Johansson, and Katy Perry.
But the deeper, creaky voice produced by dragging out certain syllables during a sentence in the lowest vocal register is also a prominent feature of the singing voice.
It has been regularly deployed to convey a sense of depth, intensity of emotion, and empathy by everyone from Mick Jagger to Britney Spears, such as in the opening lines of “Street Fighting Man” and “…Baby One More Time”, respectively.
Janis Joplin, Lady Gaga, and Nirvana singer Kurt Cobain are other well-known proponents on the form.
Vocal fry involves dropping the voice to its lowest natural register, which changes the way a person’s vocal folds vibrate together. Those changes create inconsistencies in the vibrations and lend the speaker’s voice a subtly choppy or creaky quality.
The technique also forms the basis of the hunting songs of the 73 species of cetaceans with teeth, collectively known as toothed whales, which use it to locate their prey through echolocation.
They use this process to bounce sound waves off the surroundings in the dark, as deep as two kilometres beneath the waves, and so detect their prey.
The lower frequency of the deeper pitch of the vocal fry make for better hunting because their longer wavelength and greater energy means they can travel further.
Other toothed whales include the beaked, killer and vaquita whales, along with the narwhal.
While many people find vocal fry in human speech jarring – even as others find the deeper sound authoritative, and others find the technique a bit over the top in singing – in toothed whales the register is an unalloyed success, according to a study in the journal Science, presented at the American Association for the Advancement of Science in Washington on Thursday.
“Vocal fry allows whales access to the richest food niches on earth – the deep ocean,” said Professor Peter Madsen, of Aarhus University in Denmark.
“While vocal fry may be controversial in humans and may be perceived as everything from annoying to authoritative, it doubtlessly made toothed whales an evolutionary success story,” he said.
When using vocal fry, the vocal cords are only open for a very short time – meaning the animals use very little breathing air in the process.
“This air-economy makes it especially ideal for echolocation. During deep dives, all air is compressed to a tiny fraction of the volume on the surface,” Professor Madsen said.
Andrea Ravignani, of the Max Planck Institute for Psycholinguistics, in the Netherlands, who was not involved in the study, said: “This study reveals that toothed whales can display extraordinary vocal abilities while diving at 1000 meters and feasting on seafood. At least vocally, humans are not so special after all.”
When toothed whales hunt in deep and murky water they produce short, powerful, ultrasonic echolocation clicks at rates up to 700 per second to locate, track and catch prey.
The discovery that toothed whales employ vocal fry techniques is part of a bigger study, which found that these animals, like humans, have at least three vocal registers – the vocal fry register, which produces the lowest tones, the chest register, which is similar to our normal speaking voice, and the falsetto register, which produces even higher frequencies.
Overall, the researchers reveal that toothed whales have a wide vocal range, akin to that of a human, with three distinct vocal registers, just like humans.
Only humans and crows have previously been found to have different vocal registers – a range of tones produced by a particular vibratory pattern of the vocal folds.
Toothed whales use the two higher registers to produce a wide range of pulses and whistles to communicate with their fellow creatures, with the lower one used for hunting.
The registers are key because they allow toothed whales to convey a host of emotional and complicated languages in the upper registers, at high frequency, as well as to blast out really loudly at much lower frequencies at five times the volume of any trumpeter, making the loudest noise of any animal on the planet and without damaging their lungs.
Toothed whales can produce an acoustically rich collection of grunts, bursts, and whistles used to compose complex vocalizations used for social communication.
Vocal fry isn’t just for celebrities; all people employ it to some extent. And it’s not just women that use it in their speaking voices, although it is thought to be more noticeable when they do because men typically have a lower pitch.
While the technique is employed to enhance the feeling of songs, it’s not clear why some people have more of a creaky voice than others.
One theory suggests that a lower pitch is a sign of empowerment, so people may be unconsciously signalling their own sense of personal power using this voice quality. Another hypothesis comes to the opposite conclusion: That vocal fry is a sign of anxiety and stress, causing the voice box to tighten.