Orangutan's vocal control offers insight into early human speech

"Our research proves that orangutans have the potential capacity to control the action of their voices," researcher Adriano Lameira said.

By Brooks Hays

INDIANAPOLIS, July 27 (UPI) -- A young orangutan has shown the ability to make vowel-like calls, mimicking the tone and pitch of sounds made by researchers -- a first.

Scientists say speech is a learned behavior. Until now, apes hadn't demonstrated the ability to learn new vocalizations. Thus, researchers argued the evolutionary origins of language lie with early humans -- not our earliest ancestors.


The latest discovery has scientists reconsidering.

The young orangutan's name is Rocky. He's 11 years old and lives at the Indianapolis Zoo. For several months when Rocky was eight, researchers attempted to teach the ape new sounds. Without disrupting his environment or schedule, biologists engaged in regularly copycat games, introducing Rocky to a range of new vocalizations -- regularly changing tone and pitch.

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Rocky showed the ability to mimic the varied sounds, and responded in a way that reflected human conversation patterns. Analysis of a database of orangutan calls confirmed Rocky's vocalizations were entirely new.

"Instead of learning new sounds, it has been presumed that sounds made by great apes are driven by arousal over which they have no control, but our research proves that orangutans have the potential capacity to control the action of their voices," Adriano Lameira, an anthropologist at Durham University, said in a news release. "This indicates that the voice control shown by humans could derive from an evolutionary ancestor with similar voice control capacities as those found in orangutans and in all great apes more generally."


The latest research builds on previous analysis of Rocky's mimicry, arguing that voice control isn't limited to specific species but reflective of broader capabilities among all orangutans -- and potentially all great apes.

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Lameira and his colleagues detailed these abilities and their relevancy to the evolution of language in a new paper, published this week in the journal Scientific Reports.

"This opens up the potential for us to learn more about the vocal capacities of early hominids that lived before the split between the orangutan and human lineages to see how the vocal system evolved towards full-blown speech in humans," Lameira concluded.

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