Chimp populations, like humans, have local customs, and these cultural practices can spread to other troops, researchers say.
The spread of such traditions and innovations to different groups is an important hallmark of culture, and a necessary part of development through social learning, they say.
Andrew Whiten at the University of St Andrews, UK, and colleagues taught individual chimpanzees one of two ways to solve complex foraging tasks, and observed how the different techniques spread across two sets of three groups. The chimps had to manipulate a combination of buttons, levers or discs to extract treats from cubes. Watch a video of chimps completing the tasks.
Although no chimps cracked the puzzles without instruction during an initial encounter with the cubes, animals in the two groups learned quickly how to work the devices when watching a peer who had been trained in one of the two possible sets of solutions.
Within a few days, most chimps mastered the techniques that had been "seeded" this way in their group.
The cubes were then moved into the view of a second set of chimp groups, so they could observe their respective neighbours solving the tasks. The new groups learned the same techniques as demonstrated in the adjacent enclosure, and then passed their set of tricks on to a third group in another round of experiments.
"This is the first time we can show such transmission of socially learned behaviour patterns between groups of animals", says Antoine Spiteri, who was involved in the study.
The team had previously found social learning of similarly complex tasks within groups, but to spread widely, cultural traditions must catch on with new groups, too, the researchers say.
Carel van Schaik at the University of Zurich in Switzerland, who studies orang-utan culture, says that the new results show "beyond a doubt that apes are capable of transmitting pretty complex traditions. The question is now to what extent this reflects what's going on in the wild."
Van Schaik's group hopes to find out more about this by measuring "peering" behaviour in wild orang-utans - highly-focused watching of another animal from a short distance which may be a potential mechanism for social learning. "The whole picture is coming together", he says.
Next Spiteri wants to unravel exactly how chimp culture spreads: "We need to see how status and prestige of different animals affect who learns from whom."
An analysis of Whiten's group's studies already shows that the order in which individuals in each group picked up new traditions was similar for foraging tasks, but not for unrelated tasks, giving first insights into the dynamics of cultural transmission.