We yawn. So do bears, bats, guinea pigs, dogs and others. It’s a mystery as to why. In fact, it’s likely the least understood common human behavior. It’s also a contagious behavior that may have social and communicative functions.
Source: NPR, May 15, 2017.
But recently, two more species have been added to the list of contagious yawners: dogs and chimpanzees. When two groups of chimpanzees were show videos of familiar and unfamiliar chimps yawning, the group watching the chimps they knew engaged in more contagious yawning. This study, by Matthew Campbell and Frans de Waal, supports the theory that yawning plays a role in the evolution of social bonding and empathy.