London, August 11 (ANI): Orang-utans have been caught on camera performing "pantomimes", behaviours that are exclusive to humans.
Non-human great apes such as orang-utans and chimpanzees were already known to display meaningful gestures. But that is a far cry from displaying actions that are intentionally symbolic and referential - the behaviour known as pantomiming.
"Pantomime is considered uniquely human," the New Scientist quoted Anne Russon from York University in Toronto, Canada as saying.
"It is based on imitation, recreating behaviours you have seen somewhere else, which can be considered complex and beyond the grasp of most non-human species."
Yet over years she has worked with great apes, Russon has seen several cases that she thought could be considered pantomiming.
So to gather more concrete evidence, she and colleague Kristin Andrews searched through 20 years of data on the behaviour of free-ranging, rehabilitated orang-utans.
They found 18 cases of orang-utans clearly acting out a message.
Sometimes it was a simple mime, such as body-scratching using a stick, probably to encourage another orang-utan to groom the actor.
In more elaborate cases, orang-utans faked an inability to do something in order to elicit help.
"Now it has to be clear that this is not exclusive to humans," says Robert Shumaker of Indianapolis Zoo, Indiana, who has studied orang-utans. I
It adds to the evidence of complex culture among orang-utans, which have even been seen to fashion musical instruments.
The study is published in Biology Letters. (ANI)