Yawns CON­TA­GIOUS for wolves, too

Close bond between ca­nines boosts fre­quency

SundayXtra - - FRONT PAGE - By Karen Ka­plan

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 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 be­haviourally linked to our ca­pac­ity for em­pa­thy,” the Ja­panese re­searchers who con­ducted the study state.

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. But there’s a twist: 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.

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 be­hav­iours,” they noted in their study, pub­lished Wed­nes­day by on­line jour­nal 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 an in­nate sus­cep­ti­bil­ity to con­ta­gious yawn­ing, then wolves should do it, too. Wolves are the clos­est liv­ing rel­a­tives of dogs, and they are “a highly so­cial and co- op­er­a­tive species,” the re­searchers wrote.

So off they went to the Tama Zoo­log­i­cal Park, a 52-hectare zoo about 32 kilo­me­tres from the heart of Tokyo. Among the res­i­dents was a pack of 12 wolves — a mother, a fa­ther and their 10 off­spring (five males and five fe­males). They logged 254 hours of ob­ser­va­tion time over a five-month pe­riod, pay­ing spe­cial at­ten­tion to in­stances of yawn­ing.

Only yawns that oc­curred when wolves were awake, re­laxed and not in dis­tress were in­cluded in the anal­y­sis. When such a yawn was ob­served, the re­searchers noted the wolf in­volved, the other wolves nearby (de­fined as be­ing “within two body lengths”), and where th­ese wolves were look­ing when the yawn oc­curred. (Nearby wolves were not counted if their eyes were closed at the time of the yawn.) Then the re­searchers watched the nearby wolves for the next three min­utes to see if any of them yawned, too. If they did, they noted the gap in time between the ini­tial yawn and the fol­lowup yawn.

As a con­trol, the re­searchers also watched the wolves for three-minute pe­ri­ods that didn’t start with a yawn.

The sci­en­tists found the wolves were in­deed 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 fol­lowup yawn if the two an­i­mals had a strong so­cial bond. (Not only that, but among fe­males, the closer the bond, the shorter the gap between the first and sec­ond yawn.) 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, co- or­di­nat­ing ac­tiv­i­ties has ob­vi­ous adaptive ad­van­tages, since it pro­motes so­cial co­he­sive­ness of the pack.”

The fact yawns from favourite fel­low wolves were more con­ta­gious than yawns from oth­ers adds sup­port to the no­tion con­ta­gious yawn­ing is re­lated to em­pa­thy, and the “ba­sic build­ing blocks of em­pa­thy might be present in a wide range of species,” they wrote.

The study was funded by the Ja­pan So­ci­ety for the Pro­mo­tion of Sci­ence and the Ja­panese Min­istry of Ed­u­ca­tion, Cul­ture, Sports, Sci­ence and Tech­nol­ogy.

— Los An­ge­les Times

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