Richard Collins: Cultural loss in chimp groups — and the role of humans

Nor is cultural variation peculiar to humans; animals exhibit it also.

Bird song repertoires vary geographically. Wrens have local accents. I remember tracking down a strange caller in the laurel forests of Madeira, only to find that the bird was a humble chaffinch. It just happened to speak a different dialect to the ones in my garden at home.

Humpback whale pods evolve a new ‘song’ every year. It’s an essential passport renewal. When Keiko, the orca star of the Free Willy film, was returned to the North Atlantic, he was ostracised by his wild cousins probably because he couldn’t speak the current whale dialect. Exclusion cost him his life.

But are there also body-language ‘dialects’ among animals?

Dogs and wolves share 98.9% of each other’s genes. The two species began to go their separate ways a mere 33,000 years ago, the blinking of a palaeontologist’s eyelid. How different their two cultures have become in the short time since then! Dogs bark. Wolves don’t; they howl. Your pet can suss out your mood and ‘read’ your posture. Captive wolves, zoo keepers tell me, never master such skills. These behavioural differences result from artificial selection, but cultural variation must surely occur also among canine populations in the wild?

The Ivory Coast Chimpanzee Project began in 1979. Wild chimp behaviour has been studied intensively in the Tai National Park or 45 years, with selected individuals being monitored from the moment they rise in the morning until they go to bed at night.

New paper alert 📢📢📢
Study from @TaiChimpProject shows cultural use of some gestures to solicit copulations and loss of one signal due to human activity.
Signal traditions and cultural loss in chimpanzees: Current Biology https://t.co/D8Fm6eZMle

— Taï Chimpanzee Project (@TaiChimpProject) February 3, 2025

Researchers from the Manx Planck Institute have identified differences in the chimps’ body-language signals, particularly in the chat-up lines used by males, of four separate social groups.

According to a paper just published, the scientists documented ‘454 copulation solicitation events’. They have identified "four distinct auditory gestures produced by males to solicit copulations, each involving the use of objects to produce noise — branch-shake, heel-kick, knuckle-knock and leaf-clip".

But, as with the evolution of dog and wolf behaviour, chimp body-language can change in response to human interference. Poaching has been a problem in the National Park. Since 1999, the researchers say, the chimp population has been losing members. In 2008, a poacher broke into the Park and killed the last adult male in one of the social groups being studied.

Several years followed in which there were no adult males present. As a result, one traditional courting gesture, ‘the knuckle-knock’, disappeared; it has not been used members of the group for 17 years.

Dialects in #chimpanzees. Human influence has led to cultural loss & calls for #conservation strategies to include preserving cultural distinctiveness. New study in @CurrentBiology by @MPI_EVA_Leipzig, @ISC_MJ & @TaiChimpProject. https://t.co/Z1pRScDjBU & https://t.co/112rseobsC pic.twitter.com/nq74qEwScv

— MPI-EVA Leipzig (@MPI_EVA_Leipzig) February 5, 2025

"There is an urgent need to integrate the preservation of chimpanzee culture into conservation strategies," according to Mathieu Malherbe, lead author of the recent paper.

"This initiative is crucial, not only for the survival of the species but also for understanding our own evolutionary history," he says.

• Mathieu Malherbe et al. Signal traditions and cultural loss in chimpanzees. Current Biology. 2025