Chimps, our favorite primate cousins, communicate with each other through a complex gesture language, partially decoded by scientists. Depending on the situation and the gesture, chimps tell each other things like “Stop that,” “Climb on me,” or “Move away.” Now, an exciting new study found that chimps also communicate through vocalization. Researchers found that the primates would “speak” to their peers and relay what their favorite fruits are and where the best trees can be found.
“Chimpanzees definitely have a very complex communication system that includes a variety of vocalisations, but also facial expressions and gestures,” says project leader Ammie Kalan of the Max Planck Institute for Evolutionary Anthropology.
“How much it resembles human language is still a matter of debate,” she says, “but at the very least, research shows that chimpanzees use vocalisations in a sophisticated manner, taking into account their social and environmental surroundings.”
The biologists closely followed chimpanzees for more than 750 hours in the Ivory Coast’s Taï Forest and analyzed their calls. When the chimps encountered fruits from Nauclea trees, they elicited high pitched calls. Further yet, when the trees were small the high pitch was kept, while bigger trees were relayed to peers with lower hums. In total, some 379 food calls produced for five different food species were analyzed, but higher pitched calls were produced for the Nauclea.
“I never tried these fruits myself, but they do smell very good in the forest,” Kalan says. “They are also quite big and easy to ingest, and we also know that they have a high energy content, which is important for wild animals.”
Granted, this is far from being a conclusive finding and the authors highlight further work is needed to determine whether variation in food call pitch can influence receiver foraging behaviour. Still, if this is true, then chimps communicate with fellows in their community which foods are of better quality and where these are found, which is impressive in itself and not that unlikely considering complex chimp behaviour. Besides a complex gesture language, chimps establish cultures and pass down skills to their peers. They even exhibit fashion-like behaviour.
Findings appear in Animal Behaviour.