Little Jake and Little Joey embrace in a forested sanctuary in Zambia. Hugs like these could help chimpanzees strengthen social bonds before times of stress.
Jake Brooker / Chimfunshi Wildlife Orphanage Trust
Hugs and kisses could help primates keep the peace.
Both chimpanzees and bonobos appear to use friendly physical touch as a way of easing tension among group members in stressful situations, researchers report July 22 in the Proceedings of the Royal Society B. Embraces, pats, hand-holding, genital touches, sticking fingers in each other’s mouths — these buddy-buddy behaviors form the social glue that helps groups stick together, says Zanna Clay, a primatologist at Durham University in England.
Humans could learn a lesson about this love language from our ape relatives, Clay says. Before a sporting event, competition or other intense encounter, a bit of physical touch might make people feel calmer and more connected. “Physical closeness is a really powerful way of managing stress,” she says.
Scientists knew that chimpanzees and bonobos use physical touch to resolve conflicts and offer comfort in times of distress. But Clay’s team noticed that the animals were also getting friendly when no fighting had occurred, says Jake Brooker, a primatologist now at Utrecht University in the Netherlands. He wondered if apes used cuddles to prevent conflicts, not just resolve them.
The researchers observed five different groups of chimps or bonobos in sanctuaries in Zambia and the Democratic Republic of Congo. They filmed the animals before, during and after offering them a limited number of peanuts. When the apes learned about the incoming treats, they’d get nervous and excited, Brooker says. That’s because there weren’t enough peanuts for everyone to eat their fill.
But the more friendly touches the animals shared before feeding, the more likely they were to eat together in peace, the team found. That trend held true for bonobo and chimp groups alike. Chimps often get a bad rap, Clay says; they’re known for being surly and aggressive, while bonobos are considered the ape world’s free-loving hippies. The team’s results suggest the two species may be more similar than people think.
Clay can’t say for sure whether touchy-feely behaviors help apes tolerate one another — or if more tolerant groups just tend to touch each other more. But, she says, it’s probably a two-way street.
