Wild chimpanzees use at least 66 distinct gestures to communicate, according to new research.
Chimpanzee behaviour filmed
A team of scientists, from the University of St Andrews in Scotland, filmed a group of chimpanzees at Budongo Conservation Field Station, Uganda. The footage was then analysed, looking for signs that the chimps were intentionally signalling to each other.
To be sure that the chimpanzees were making deliberate signals, the researchers looked for clear signs such as the gesturer looking at its audience, or repeating the gesture to get a response. Earlier studies on captive chimpanzees had revealed about 30 different types of gesture, so this new research shows the species to have a larger repertoire than previously thought.
According to Dr Catherine Hobaiter, one of the researchers, “We think people previously were only seeing fractions of this, because when you study the animals in captivity you don’t see all their behaviour. You wouldn’t see them hunting for monkeys, taking females away on ‘courtships’, or encountering neighbouring groups of chimpanzees.”
Deciphering the chimpanzee repertoire
The next stage of the project will be to decipher the meanings of the different gestures. In some cases the chimpanzee’s intention appears to be clear. For example, in one piece of footage, a mother chimpanzee reaches her arm towards her daughter, indicating that the mother wants to move away and is requesting that her daughter climb onto her.
However, actions may not always have the effects the signaller intended. “So to understand the intended meaning, it’s no good just discovering the gesture’s typical effect. We have to look for what effect makes the signaller stop gesturing and appear satisfied and content with the outcome, to be sure that that was what they intended,” said Professor Richard Byrne, another of the researchers.
Gestures common to great apes
Dr Hobaiter said, “This supports our belief that the gestures that apes use (and maybe some human gestures too) are derived from ancient shared ancestry of all the great ape species alive today.”
Liz Shaw, ARKive Species Text Author