We’ve all seen videos of “talking” animals, from thrashing parrots and warbling huskies to petrified cats. Bizarre and seemingly human-like as these behaviors might be, they’re all variations on the animals’ natural vocal repertoires. Rocky the orangutan is another story. Researchers say he’s learned to imitate human speech by making noises he’d never use otherwise. They published their findings in the journal Scientific Reports. 

Teaching Rocky to talk is not just a party trick. As our very near relatives, the great apes have a lot to teach humans about our natural history. One element of that history is speech. Scientists have long believed that humans are the only apes who can control their voices enough to really speak, but new research is challenging that idea. A 2015 study by Adriano Lameira, president and founder of the Pongo Foundation, found that a 50-year-old orangutan named Tilda could use her voice to echo the pace and rhythm—although not the actual sounds—of human speech. 

Lameira wondered what else orangutans could do. He and his colleagues designed an experiment in the form of a game for an 8-year-old male named Rocky who lives at the Indianapolis Zoo. Researchers had had their eye on Rocky for a few years, as the young ape already appeared to regularly use non-orangutan noises in order to attract his caretakers’ attention. 

In the game, Rocky watched and listened as an experimenter spoke words at various pitches and tones, then tried to repeat each sound as precisely as he could. He got pretty good at it after a while, as you can see here: 

The researchers recorded all of Rocky's unique, human-like vocalizations, which they coined “wookies.” To be sure that these wookies weren’t actually normal ape noises, they compared them to more than 12,000 hours of audio observation of 120 orangutans, both wild and captive. But Rocky’s wookies were unique. He really was controlling his voice in a completely novel way, a fact Lameira says speaks volumes about primate evolution: "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." 

[h/t New Scientist]

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