London, Sept 9 : It's not just humans who like cuddling after a heated argument with a friend, for chimps too follow in their footsteps by comforting each other with a consoling hug and a reassuring peck on the cheek.
That's the conclusion of a study at Chester Zoo.
The behaviour could indicate some level of empathy, Dr Orlaith Fraser told the British Association Science Festival.
"We can't actually say what's going on in a chimpanzee's mind; we can only deduce from their behaviour what's going on," BBC quoted the Liverpool John Moores University researcher, as telling.
"Because this behaviour is actually reducing stress levels and it's being offered by a valuable partner, it seems likely that this is an expression of empathy," Fraser added.
To reach the conclusion, the research team spent 18 months observing 22 adult chimps at Chester Zoo.
They watched closely what happened immediately after the animals had a scrap - perhaps a fight over food, a mate or simply where to sit.
In about 50 percent of cases, the victim in the fight would be consoled by another member of the group. The soothing was always done by a valuable - or best - friend, a chimp with whom the victim would routinely play or share food.
The consolation was usually in the form of a kiss or embrace, a grooming session or even play - which helped in reducing stress levels - indicated by the return to the animals' normal activities of self-scratching and self-grooming.
"If these chimpanzees are actually motivated by empathy to console victims of aggression, they must first of all be able to recognise that the victim is distressed and then they must know what to do in order to act appropriately to respond to this distress," said Dr Fraser.
"This is something often thought to be a unique trait to humans, so understanding the link between consolation and stress reduction in chimpanzees is an important step towards understanding whether or not chimpanzees are capable of this level of empathy," the researcher added.
The study has been published in the journal Proceedings of the National Academy of Sciences.