People do it. They see someone near them yawn and then they yawn too. But new research shows that yawning is contagious among animals, mainly wolves, as well.
Watching a pack of wolves at the Tama Zoological Park outside Tokyo last year, Japanese researchers found that the sight of a wolf yawning often triggered yawning in packmates. And the more time the wolves spent together, the more likely it was to happen.
This phenomenon was recently demonstrated in bonobo monkeys, but this is the first study to document the act in wolves.
Yawning in response to another yawn isn't exactly an emotional reaction, but their contagious nature has been "clinically, psychologically, neurobiologically, and behaviorally linked to our capacity for empathy," the study authors wrote in the journal PLOS ONE.
This is as much true for humans and monkeys as it is for wolves, according to the study.
Contagious yawning is also observed in dogs; although, they don't yawn in response to yawns from other dogs, but to yawns from people. What's more, the yawns are more contagious when the person doing the yawning has a strong emotional connection to the dog. This prompted researchers from the University of Tokyo to study whether this was common among wolves, the closest living relatives of dogs.
Lead researcher and biologist Teresa Romero and her team spent 524 hours over five months observing a pack of 12 wolves at the Tama Zoological Park - its naturalistic enclosures made it the most realistic setting possible. They noted every time a wolf yawned spontaneously, then recorded the responses of any wolves nearby that had seen the yawn. The researchers also measured how frequently the wolves yawned without seeing their packmates also doing so.
Their observations showed that 50 percent of the time a wolf yawned after seeing another do so, and wolves yawned only 12 percent of the time when they didn't see another wolf do so.
Wolves with close social bonds were also more likely to demonstrate contagious yawning.
"Yawning in wolves is contagious," the researchers concluded. And that makes sense, they added.
"For a highly social animal such as the wolf, coordinating activities has obvious adaptive advantages, since it promotes social cohesiveness of the pack."