Hugging before stressful events may be an ancient way of building trust, say scientists studying apes.

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