DD Animal News – Deep in the rainforests of Côte d’Ivoire’s Taï National Park, wild chimpanzees aren’t just making noise—they’re making sense. In a new study published May 9 in Science Advances, researchers revealed that chimps are combining their grunts, barks, hoots, and pants into complex vocal “bigrams” that carry specific meanings. It’s the clearest sign yet that our closest primate cousins may be working with the earliest blueprints of human-like language.
More Than Monkey Talk
Chimpanzees have long been known for their rich vocal repertoire—around a dozen unique calls—but what scientists didn’t know was how those calls were strung together. Turns out, it’s not random noise.
Using more than 4,300 audio recordings from 53 adult chimpanzees taken between 2019 and 2020, evolutionary biologist Cédric Girard-Buttoz and his team at the CNRS in France discovered that chimps regularly combine calls into two-part sound units, or “bigrams.” Think: grunt + bark or pant-hoot + scream.
These combinations, the researchers found, aren’t just chatter. They carry meaning—and the order matters. For example, a “hoo + grunt” combo is often used during rest or feeding. Flip that to “grunt + hoo” and it’s mostly used during travel or when groups are merging. This flip-flop in meaning based on order is a behavior not previously seen in nonhuman animals and is eerily similar to the way word order affects sentence meaning in human languages.
More Than Just One Trick
What’s especially wild is that chimps don’t just use one rule for combining sounds—they use at least four. Some sounds modify the meaning of others, similar to how humans add suffixes. Others build entirely new meanings from combinations, or rely on the order of sounds to convey something totally different.
The discovery adds weight to the idea that the roots of human language might be much older than we thought, and could even stretch back to our shared ancestors with chimpanzees.
What Makes This Different?
Most animals that combine calls do it in very specific, high-stakes moments—like giving predator warnings or an alarm for a dangerous situation. But the chimps in this study were combining calls during everyday moments: resting, socializing, and traveling. That kind of variety suggests a much more advanced and flexible communication system.
And it gets better: the team suspects chimps may be building longer sequences—three or four sounds in a row—with their own kind of sentence structure. They’re now analyzing whether chimps place a “subject” sound before a “verb” one, just like we do in human language.
So What’s Next?
Girard-Buttoz and his colleagues want to test whether this kind of communication exists in bonobos too. Bonobos—our other closest ape relatives—have already shown some call-combining behavior, but chimps seem to be taking it to the next level.
“It’s a super exciting advance of the field,” says Simon Townsend, an evolutionary anthropologist at the University of Zurich not involved with the new research. “The chimp combinatorial vocal system is more complex than we previously thought.”
So next time you hear a grunt or pant from the primate house at the zoo, just remember: they might not be making noise—they might be making language.
