Koko the Gorilla Reveals Apes May be Closer to Speaking Than Previously Thought (VIDEO)

First Posted: Aug 14, 2015 09:19 AM EDT

Apes may be closer to talking than you might think. It turns out that Koko the gorilla, best known for her ability to use American Sign Language, also used vocalizations when "speaking" with researchers.

"I went there with the idea of studying Koko's gestures, but as I got into watching videos of her, I saw her performing all these amazing vocal behaviors," said Marcus Perlman, one of the researchers, in a news release. "Decades ago, in the 1930s and '40s, a couple of husband-and-wife teams of psychologists tried to raise chimpanzees as much as possible like human children and teach them to speak. Their efforts were deemed a total failure. Since then, there is an idea that apes are not able to voluntarily control their vocalizations or even their breathing."

The theory, instead, went that the calls that apes make pop out almost reflexively in response to their environment. For example, they will automatically respond to the appearance of a dangerous snake.

Now, though, researchers believe that this may not be the case. Scientists examined 71 hours of Koko interacting with humans, and found repeated examples of Koko performing nine different, voluntary behaviors that required control over her vocalization and breathing. These were learned behaviors and not part of the typical gorilla repertoire.

The researchers watched Koko blow a raspberry when she wanted a treat, blow her nose into a tissue, play wind instruments, huff moisture onto a pair of glasses before wiping them with a cloth, and mimic phone conversations by chattering wordlessly into a telephone cradled between her ear and the crook of an elbow.

The findings show that gorillas do have control of their breath and have some flexible control over their vocal tract, which is essential for speech.

"Koko bridges a gap," said Perlman. "She shows the potential under the right environmental conditions for apes to develop quite a bit of flexible control over their vocal tract. It's not as fine as human control, but it is certainly control."

The findings are published in the journal Animal Cognition.

Want to learn more? Check out the video below, courtesy of YouTube.