Previous studies on chimpanzees have suggested that the animals have about 30 different gestures.
However, a team of researchers from the University of St Andrews in Scotland has now revealed that wild chimpanzees use at least 66 distinct gestures to communicate with each other.
They filmed a group of the animals in order to decipher this ‘gestural repertoire’ and then studied 120 hours of footage of the chimps interacting, looking for signs that the animals were intentionally signalling to each other.
“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,” lead researcher Catherine Hobaiter told the BBC.
“You wouldn't see them hunting for monkeys, taking females away on ‘courtships’, or encountering neighbouring groups of chimpanzees," she added.
Hobaiter spent 266 days observing and filming a group of chimpanzees in Budongo Conservation Field Station, Uganda.
"I''ve spent two years studying these animals, so they know me. I follow them through the forest and they just ignore me completely and get on with their daily lives," she said.
She and her colleague, Prof Richard Byrne, scrutinised the footage and categorised each distinct gesture.
They looked for clear signs that the animals were making deliberate movements that were intended to generate a response from another animal.
"We looked to see if the gesturer was looking at their audience," explained Professor Byrne.
"And we looked for persistence; if their action did not produce a result, they would repeat it."
The team is still studying the footage for the next stage of their project - to figure out what each gesture means.
The results have provided clues about the origins of chimps' gestures, suggesting that they are a common system of communication across the species, rather than each movement being a learned custom or ritual within one social group.
In fact, by comparing these observations with those of gestures made by gorillas and orangutans, the researchers showed there was significant overlap in the signals used throughout the family of great apes.
“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," said Hobaiter.
The findings are published in the journal Animal Cognition.