Gestures used by chimpanzees to communicate with each other follow some of the same rules intrinsic to human language, according to a study of wild chimps living in Uganda’s Budongo Forest Reserve.
Budongo Central Forest Reserve has a total surface of approximately 825 square km, of which 430 square km is continuous forest. The reserve sits atop the Albertine Rift, part of the Great Rift Valley, and is located within the boundaries of Murchison Falls National Park.
Raphaela Heesen, at the University of Roehampton in the UK, and colleagues analysed video recordings of more than 2000 uses of 58 different types of “play” gestures, and found that more frequently used gestures were shorter in duration, and that longer signing sequences were made up of shorter, syllable-like gestures. These two patterns are known to apply to all human languages.
“Primate gestural communication is, of course, very different to human language, but our results show that these two systems are underpinned by the same mathematical principles,” says Heesen.
Like other great apes, chimpanzees lack the ability to speak but make use of meaningful gestures, much like deaf people signing to each other.
In the case of spoken language, this translates to longer words consisting of shorter syllables.
Lead researcher Raphaela Heesen said: “We hope that our work will pave the way for similar studies, to see quite how widespread these laws might be across the animal kingdom.”
As well as using hand and foot gestures, chimps communicate with noises, body postures and facial expressions. Research findings published in September last year found that that chimps and human toddlers use similar stamping, pointing and clapping tactics to get attention.
The latest findings appear in the journal Proceedings of the Royal Society B.