WIKIMEDIA, ZYANCEAn orangutan named Rocky impressed scientists at Durham University, in the United Kingdom, by mimicking more than 500 vowel-like sounds in human speech, the researchers reported today (July 27) in Scientific Reports It’s the first time a nonhuman primate has demonstrated this level of vocal fold control, hinting out how humans evolved speech after they split off from great apes.
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The discovery, led by Dr Adriano Lameira of Durham University, UK, shows that orangutans could have the ability to control their voices.
Eight-year-old Rocky was studied at Indianapolis Zoo in the USA, where he still lives, between April and May 2012.
Rocky the orangutan now knows how to talk like humans.
While with Rocky, the researchers conducted a simple, but extremely insightful test. If he copied the sound correctly on the first try, he was rewarded.
For the imitation game, a researcher made random sounds with their voice, varying the pitch and tone. These skills could suggest that humans’ ability to speak can be traced back to the great apes.
Surprised scientists then asked him to mimic the tone and pitch of human vowel sounds and compared what he said to a large database of recordings of wild and captive orangutans.
“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”.
The results showed that “a nonhuman great ape can achieve levels of volitional voice control qualitatively comparable to those manifested in humans”, such as “real-time, dynamic and interactive” vocal control “beyond the species-specific vocal repertoire”, the researchers wrote.
Additionally, the experimenter was someone Rocky had never seen before, ensuring the orangutan did not develop conditioned responses. It’s an important distinction, the scientists suggest, because it now appears the ape vocal system was evolving parallel to the human one.
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They believe Rocky could be the key to understanding how human speech evolved.
