It’s an old party trick—sucking helium from balloons so you can sing like a Wizard of Oz munchkin. When gibbons inhale this non-toxic gas, researchers can detect much more sophisticated impersonations. It turns out that gibbon vocalization techniques mirror those of highly trained soprano opera singers.
“We’ve shown how the gibbons’ distinctive song uses the same vocal mechanics as soprano singers, revealing a fundamental similarity with humans,” explains Takeshi Nishimura, an associate professor with the Primate Research Institute at Japan’s Kyoto University.
Scientists had previously believed that human speech was possible, in part, due to suspected evolutionary changes in the larynx, tongue, and vocal tract. But Nishimura’s new findings suggest that humans may not have vocal anatomy and ability as unique as previously thought.
Listen to a gibbon call:
And to a gibbon on helium:
We share voice-box physiology with gibbons, and likely other primates, but we also share the way we manipulate sound, Nishimura explains. With both humans and gibbons, the origin of the sound—the larynx—is independent from the vocal tools (or training) used to tailor audible messages.
(Related: “Humming Fish Reveal Ancient Origin of Vocalization.”)
Nishimura and his colleagues studied a young female white-handed gibbon at the Fukuchiyama City Zoo in Kyoto, where they exposed her to helium-rich air. Helium, which shifts gibbon sounds to a resonance that is easier to assess with acoustic equipment, is common in animal vocalization research.
This graceful primate normally makes intense, pure-tone—or single-frequency—calls that can travel more than a mile through dense tropical forests in their native Southeast Asia.
It was probably the need to communicate with distant neighbors in such bustling habitats that produced the unique gibbon song. “Such ecological and social requirements forced gibbons, using a soprano technique, to produce their pure-tone and loud voices,” Nishimura said.
(See video of a swinging gibbon.)
Human soprano opera singers learn to shift their vocal range to make their high-pitched sounds the most powerful ones, he explained.
“[Gibbons] use human professional singing techniques with little effort,” he added.
While gibbons won’t be mimicking human conversation any time soon, says Nishimura, “this gives us a new appreciation of the evolution of speech in gibbons while revealing that the physiological foundation in human speech is not so unique.”
(See more gibbon photos in “Pictures: Hundreds of Rare Gibbons Found in Vietnam.”)