Body Talk

Scientists decode how gorillas talk to each other — watch

Originally Published: 

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You’ve almost certainly seen an image of a gorilla beating its chest at some point.

It’s one of the ape’s most distinctive behaviors.

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Scientists have long thought that gorillas beat their chests to communicate with each other. But they didn’t know exactly what was being communicated — or how.

That’s changed.

New research from the Max Planck Institute for Evolutionary Anthropology suggests chest-beating may help gorillas identify each other and gauge whether they may be threats or potential mates.

Along with the Dian Fossey Gorilla Fund, the researchers monitored 25 wild adult male silverbacks in Volcanoes National Park, Rwanda. They also made audio recordings of six beating their chests.

(Tap to hear the surprising sound.)

Dian Fossey Gorilla Fund

Larger gorillas made significantly deeper drumming sounds than smaller ones. The difference was so clear that researchers could reliably tell a gorilla’s size based on sound alone.

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The researchers say larger gorillas may have larger air sacs near their larynx, which would produce a lower frequency sound.

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Study author Edward Wright tells Inverse:

“We focused on body size since it likely indicates fighting ability and correlates with reproductive success in male mountain gorillas (our previous research) as well as many other species in the animal kingdom.”

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The researchers also found variations in how long different gorillas beat their chests, which isn’t related to size but may help identify which gorilla was making the sound.

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So why communicate this way when looking at each other would convey the same information? The researchers suggest that gorillas’ dense jungle habitats make sound more reliable than sight.

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Study author Edward Wright tells Inverse:

“Other than body size chest beats may also convey other information such as dominance rank, age, sex, individual identity but this is a topic for future research.”

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