Orangutans give clue to early human speech
Meet Rocky, an 11-year-old orangutan who might reveal clues to how human speech first developed.
Rocky, who lives at the Indianapolis Zoo, has been part of a Durham University study that examines orangutan vocal control to better understand how human speech evolved from that of our primordial ancestors.
Research fellow Adriano Lameira and his team found that Rocky had a knack for imitation. The great ape could produce vowel-like calls by copying the pitch and tone of sounds made by the human researchers. Rocky's sounds were then compared to those compiled in a database of orangutan calls that came from more than 12,000 hours of observation of over 120 orangutans from 15 wild as well as captive populations.
How did Rocky compare to his peers? The research team found that the sounds Rocky made were unlike those recorded in the database. Unlike the other orangutans, he was able to not only learn and replicate new sounds, but he was able to control and alter his voice in a "conversational" way.
"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," Lameira said in a press 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."
Lameira initially conducted his study of Rocky prior to joining the university's anthropology department in 2015, and this kind of research has long been a focus of his work prior to discovering Rocky's gift for gab.
He published a previous study during his days at the University of Amsterdam, in the Netherlands, when he studied a female orangutan at Germany's Cologne Zoo. She was able to make sounds that approximated human vowel and consonant-infused calls. The vocalizations were uttered with the same rhythm of human speech.
"Our latest findings open 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," he said.
The study was published in the journal Scientific Reports.
