Bonobos catch yawns from friends and family
Family or social ties in two bonobos significantly increase the likelihood that one of them, who watched a yawn, then spontaneously follows suit in response.
Yawns spread more easily between family and close friends, and from high-status monkeys to those lower on the totem pole, according to a study.
This pattern of social yawning mimics one found in humans and suggests infectious yawning is a byproduct of empathy, which coordinates emotions in a group.
"It underlines that the mechanism of yawn contagion in the two species is the same," said study co-author Elisabetta Palagi, a primate researcher at the University of Pisa in Italy.
"One of the possible functions of yawn contagion is to synchronize individuals of a social group. In humans, yawn contagion is extremely important but just between people who share strong bonds," she added.
The study was recently published in the open access journal PLOS ONE.