quote:Beatboxers can use their mouths and vocal cords to produce two sounds at once, often mimicking the percussive sounds of hip-hop music. But while some musically inclined humans are skilled at beatboxing, it’s not a very common behavior—and scientists have long wondered about its origins.
Now, researchers have observed orangutans making two sounds at the same time, a finding they say is moving them closer to answering such questions about our own evolution. Humans’ ability to produce two sounds at once may have originated with our primate ancestors, they write in a new paper published Tuesday in the journal PNAS Nexus.
While analyzing nearly 3,800 hours of video footage, scientists observed the beatboxing-like vocalizations in two separate groups of wild orangutans—one in Indonesian Borneo and the other in Sumatra, Indonesia.
Researchers describe this behavior as making “biphonations.” To produce a biophonic call combination, an animal must make a voiced and unvoiced noise at the same time, reports the Telegraph’s Joe Pinkstone. Voiced sounds come from the larynx in the throat and help make the open sounds of vowels, like “ooh” and “aah.” Unvoiced sounds, for comparison, come from moving the jaw, tongue and lips—humans make these sounds when pronouncing consonants.
Among the orangutans in Borneo, males that were in combative situations would simultaneously make a chomping noise with the mouth and a grumbling noise with the larynx, according to a statement.
In Sumatra, meanwhile, females alerted their fellow orangutans to the presence of a possible predator by making “rolling calls” in their throats and mouth-based “kiss squeaks” at the same time.
The study is “opening our eyes to the diversity” of speech abilities in non-human animals, Marco Gamba, a zoologist at the University of Turin in Italy who was not involved in the research, says to New Scientist’s Sofia Quaglia.
The two studied orangutan populations live far away from each other, on separate islands. But researchers can’t yet tell if all orangutans are capable of producing two sounds at once, or whether it’s a learned behavior.
Beyond shedding some light on the talents of beatboxers, the findings may also offer clues to the origins of human speech. Researchers have long studied songbirds for insights into human vocalizations, since they can also produce two sounds at once. “But bird anatomy has no similarity to our own, so it is difficult to make links between birdsong and spoken human language,” Madeleine Hardus, an independent researcher and co-author of the study, says in the statement.
Historically, many scientists felt that great apes had “very little interesting things to teach us about vocal communication,” as study co-author Adriano Lameira, a psychologist at the University of Warwick, tells New Scientist. But these new observations—plus the close evolutionary ties between humans and primates—suggest scientists studying the evolution of human speech should give great apes another look.
“Now that we know this vocal ability is part of the great ape repertoire, we can’t ignore the evolutionary links,” says Lameira in the statement. “It could be possible that early human language resembled something that sounded more like beatboxing, before evolution organized language into the consonant-vowel structure that we know today.”