Previous studies had shown natural variation in GHC style - including palm-to-palm, wrist-to-wrist and forearm-to-forearm clasping.

BBC: Chimpanzee grooming is a 'postcode lottery'

Of the four groups studied, two engaged in GHC behaviour - one had a preference for wrist-to-wrist GHC whilst the other preferred palm-to-palm.

BBC: Chimpanzee grooming is a 'postcode lottery'

The researchers recorded GHC behaviour in four social groups of semi-wild chimpanzees living in the Chimfunshi Wildlife Orphanage Trust (CWOT) in the north west of Zambia.

BBC: Chimpanzee grooming is a 'postcode lottery'

Celebrating GHC attendees and women entrepreneurs who exit!

FORBES: Connect