Wolves' yawns are contagious, too
- Article by: Karen Kaplan
- Los Angeles Times
- August 30, 2014 - 4:33 PM
People do it. So do chimpanzees, bonobos and baboons. Even dogs do it: They yawn when someone near them yawns. But why? Scientists believe it’s a sign that these animals are capable of feeling empathy — and a new study of wolves suggests it’s more widespread among animals than experts had realized.
Yawning in response to another yawn isn’t an emotional reaction per se, but the tendency for yawns to be contagious has been “clinically, psychologically, neurobiologically and behaviorally linked to our capacity for empathy,” according to researchers who conducted the study.
Humans and other primates are more susceptible to contagious yawning when they are around those with whom they share “a close social bond.” In people, contagious yawning is more common among those who get high scores on empathy tests, and it’s less common among those on the autism spectrum who lack empathy, the researchers noted.
Yawning is also contagious for dogs. 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 has a strong emotional connection to the dog.
These observations caused researchers from the University of Tokyo to wonder whether dogs’ status as man’s best friend made them the only nonprimate species capable of contagious yawning.
“Domestic dogs are unusually skilled at reading human social and communicative behaviors,” they noted in their study in PLOS ONE. “Thus, it could be possible that dogs’ ability to yawn contagiously evolved with the capacity for reading human communicative signals.”
On the other hand, if dogs had innate susceptibility to contagious yawning, then wolves should, too. Wolves are the closest living relatives of dogs, and they are “a highly social and cooperative species,” the researchers wrote.
So off they went to the Tama Zoological Park near Tokyo to study a pack of wolves — a mother, a father and their 10 offspring.
The scientists found that the wolves were more likely to yawn after another wolf near them had yawned. But not all “trigger” yawns were the same. A yawn was more likely to prompt a follow-up yawn if the two animals had a strong social bond. Yawns were also more likely to be contagious if they could be seen, not just heard.
“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.”
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