Great Apes kiss and cuddle to keep the peace, says study

Image source, Jake Brooker / Chimfunshi Wildlife Orphanage Trust Image caption, Embrace between Little Jake and Little Joey, two juvenile male chimpanzees in a forested sanctuary

Touching, embracing and kissing before stressful events may be an ancient way of building trust, according to scientists studying the behaviour of our closest ape relatives.

Researchers at Durham University studied chimpanzees and bonobos using physical contact to reassure each other ahead of conflicts over food.

One of the most surprising findings was that chimpanzees, despite their reputation for aggression, engaged in close contact, including placing fingers in one another's mouths.

"Before stressful events, they come together, they reassure each other, they touch each other, they hug each other," said Prof Zanna Clay.

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Watch: Bonobos and chimpanzees displaying reassuring physical touch behaviours such as embracing and kissing

She described the behaviour as "a rallying cry" before a stressful event, much like a football huddle before a big match.

"It's like a 'we' rather than a 'me'," she said.

The experts studied chimpanzees and bonobos living at two great ape sanctuaries in the Democratic Republic of Congo and Zambia.

They designed an experiment to mimic natural feeding in the wild - using peanuts.

The apes were observed during the five minutes before the peanuts arrived, when they knew food was coming.

Researchers recorded instances of reassuring physical contact, including touching, embracing and kissing.

The team found that individuals who touched and hugged were more likely to access food and eat alongside each other peacefully.

More tolerant groups showed higher levels of reassuring touch, including what researchers described as "reassurance trains", in which multiple apes embraced one another in succession.

Image source, Zanna Clay / Lola ya Bonobo Sanctuary Image caption, Juvenile male Tschibo offers a comforting embrace to juvenile male Oshwe following an aggression where Oshwe was threatened