A team of researchers from Utrecht University, Durham University, and other institutions observed something remarkable at a chimpanzee sanctuary in Zambia.

Several chimpanzees from one particular group were seen dangling blades of grass from their ear holes or their behinds, for no apparent reason.

The behaviour was not seen in other chimpanzee groups at the same sanctuary, despite similar living conditions. “This shows that, like humans, other animals also copy seemingly pointless behaviours from one another,

- You stand there with your fixed expression, casting doubt on all I have to say -