Three years ago, an adult chimpanzee called Nick dipped a piece of moss into a watering hole in Uganda鈥檚 Budongo Forest. Watched by a female, Nambi, he lifted the moss to his mouth and squeezed the water out. Nambi copied him and, over the next six days, moss sponging began to spread through the community. A chimp trend was born.
Until that day in November 2011, chimps had only been seen to copy actions in controlled experiments, and social learning had never been directly observed in the wild.
To prove that Nambi and the seven other chimps who started using moss sponges didn鈥檛 just come up with the idea independently, of the University of St Andrews, UK, and her colleagues used their own innovation: a statistical analysis of the community鈥檚 social network. They were able to track how moss-sponging spread and calculated that once a chimp had seen another use a moss sponge, it was 15 times more likely to do so itself.
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A decade ago it was believed that only humans have the capacity to imitate, says of Emory University in Atlanta, Georgia. 鈥淭he present study is the first on apes to show by means of networking analysis that habits travel along paths of close relationships,鈥� he says, adding that a similar idea was shown not long ago for humpback whale hunting techniques.
Caught in the act
Copying may seem like the easiest thing to us, but not all animals are able. Chimps at the reserve in Tanzania can copy each other using twigs to fish out termites, but the baboons that watch them haven鈥檛 picked up the trick. 鈥淭hey don鈥檛 get it,鈥� says of the University of St Andrews.
Whiten 39 behaviours that were found only in some communities of chimps, suggesting these were picked up from other group members rather than being innate behaviours. Since then, more have been added, but they still number in the dozens, not the thousands.
Given how rarely chimps pick up trends, it鈥檚 exciting that someone was on hand to watch it happen in this latest study, says Whiten.
Ultimately, he says, our ability to both invent and copy meant our ancestors could exploit a cognitive niche. 鈥淭hey began hunting large game by doing it the brainy way.鈥� Imitation, it turns out, is not just the sincerest form of flattery, it鈥檚 also a smart thing to do.
Journal reference: , DOI: 10.1371/journal.pbio.1001960
