Lip-Smacking Vocalizations of Rare Baboons Hint at Human Speech

Scientists looking for the origins of human speech think they may have clue in the lip-smacking of certain primates.

The new research examined geladas, rare primates that only live in the remote mountains of Ethiopia.

A species of baboon, geladas use vocal lip-smacks during friendly encounters with one another --- a speech-like undulating rhythm significantly different from the vocalizations of other apes and monkeys that typically use just one or two syllables and lack rapid fluctuations in pitch and volume.

Geladas spend most of their time on the ground, foraging in grasslands.

Lead researcher Thore Bergman said in a press release he started focusing on the geleda vocalizations in 2006.

The geladas' vocalizations, or, "wobbles" as they are called, are structurally similar to human speech because the primates produce the sounds while smacking their lips.

"I would find myself frequently looking over my shoulder to see who was talking to me, but it was just the geladas," Bergman said. "It was unnerving to have primate vocalizations sound so much like human voices."

Both humans and geladas use a form of communication that corresponds to opening and closing parts of the mouth, said Bergan, who goes on to theorize it's possible gelada communication could sometimes have the same function as human small talk, rather than always sending a direct message.

"Language is not just a great tool for exchanging information; it has a social function," Bergman said.

Examining the similarities between human and gelada communication could help scientists to better understand how human speech arose, what eventually led to the formation of language.

Complex and intricate, and allowing people to be subtle or blunt when interacting with others, the ability to speak makes human communication superior to that of any other species, scientists say.

The findings of the gelada study are published in the journal Current Biology.

Click here to see and hear the geladas vocalizing for yourself.