A Talking Orangutan Can Help Us Understand How Humans Developed Speech

Male orangutan.Photo: Razvan Ciuca

One of the most charming things on the internet has to be that video of Mishka the husky dog telling her owners she loves them — not by, like, snuggling up with a wagging tail or licking their faces, but actually telling them. You know the one I’m talking about? Where the person behind the camera says, “Mishka, I love you,” and the dog howls back something that sounds like “Aluvyooooooooooo,” and okay, yeah, you know it’s not actual words, but you still feel something warm and fuzzy in your chest?

This one:

It’s amusing, and a little uncanny, and fulfills a particular anthropomorphic fantasy in which our animal best friends can express their affections like actual best friends. But it’s also just an auditory coincidence: A dog’s vocalizations are pretty limited — bark, growl, yip — and in this case, one of those vocalizations happened to sound like speech. Which is, of course, strictly the domain of humans.

Except new research suggests that idea may actually be too simplistic. No one’s arguing that a talking dog is actually talking, but when you look a little closer to home — at our primate cousins — there’s some evidence that other species can control their voices in a humanlike way. A study recently published in the journal Scientific Reports outlines the case of Rocky, an orangutan at the Indianapolis Zoo who can mimic the sounds of speech.

For the study, a team of researchers “conducted a game in which the ape mimicked the pitch and tone of human sounds and made vowel-like calls,” New Scientist reported. Over time, Rocky — who’d originally caught the researchers’ eye because of the unusual noises he made to attract his caretakers — learned to make “new sounds and control the action of his voice in the way humans do when they conduct a conversation,” a feat that no other ape has yet shown the ability to do. You can listen to the vocalizations (which the researchers dubbed “wookies,” for some reason) here:

To make sure they were really hearing something out of the ordinary, the researchers compared Rocky’s wookies (which, incidentally, is a half-decent band name) to a database of around 12,000 orangutan calls from more than 120 wild and captive apes. Sure enough, the wookies didn’t match anything that had been previously recorded — meaning, the study authors argued, that Rocky should cause scientists to rethink what they know about the evolution of speech.

“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,” lead study author Adriano Lameira, an anthropologist at the University of Durham in the U.K., told New Scientist. “But our research proves that orangutans have the potential capacity to control the action of their voices … 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.”

As New Scientist noted, this isn’t the first time scientists have taught an ape to mimic human speech — in 2015, Lameira co-authored a paper on Tilda, an orangutan whose calls sounded, as he described to NPR at the time, like a garbled cartoon version of someone trying to speak normally. “We are, on average, producing five consonants and five vowels per second,” he said, a pattern matched in Tilda’s gibberish noises. (Tilda, in a cool and slightly related fact, could also whistle, another behavior not seen in the wild.) But this is the first time an ape has made those noises with humanlike inflection, producing a pitch and tone within the ballpark of how people might talk to one another.

“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,” Lameira told New Scientist, “to see how the vocal system evolved towards full-blown speech in humans.” As far as we know, the apes’ noises aren’t imbued with meaning, but in this case, what’s more interesting than what they’re saying is the fact that they can say anything at all. If speech isn’t just the domain of humans, then further research could help us to better understand how we as a species got to where we are.