Wolf yawns are contagious

TOKYO, Aug. 27 (UPI) -- Everybody knows yawning is contagious. It seems like folklore, but it's true. No matter whether an expression of tiredness or boredom, research has shown that a person is more likely to yawn after they see someone else yawn. And apparently, wolves do it too. Researchers at the University of Tokyo have found that yawns pass from wolf to wolf, just as they do among humans.

Though a number of theories as to why people yawn in the first place have been bounced around over the years, there's been little consensus. But most scientists agree that the reason yawn's are contagious is that humans are empathetic.

Yawning is like a built-in, subconscious way to tell your yawning friend, "Hey, I'm with you, I'm tired too." Studies have shown yawning is more likely to be infectious among family members and loved ones, suggesting the more time people spend together and care about each other, the more likely they are to greet a yawn with another yawn.

Until now, chimpanzees were the only non-humans who'd been shown to demonstrate the contagious yawning effect. But Tokyo researchers have been able to prove that when it comes to yawning, wolves are equally as empathetic as chimps and humans.

The conclusion didn't come easy. Researchers spent 524 hours, over the course of five months, watching a pack of 12 wolves in Tama Zoological Park and waiting for them to yawn. When they did, researchers recorded; and also jotted down whether or not the wolves nearby yawned too. The result: some 50 percent of observed yawns occurred after a wolf saw another pack member yawn. Only 12 percent of yawns were unaccompanied -- the elusive solo yawns, if you will.

As has been shown among humans, researchers found yawns were most contagious among wolves with close social bonds. The work was detailed in a study published this week in the latest edition of the journal PLOS ONE.