Observant dog owners know that if they yawn, their dog is likely to do the same. It’s called contagious yawning, and it’s something that we do with one another, too. Evolutionary biologists say that we yawn when we see someone else doing so because of our capacity for empathy. But some studies have suggested that dogs yawn not because they’re feeling empathetic, but because they’re mildly stressed. Now, a team of scientists in Japan has tackled the question again. In a study reported online today in PLOS ONE, the scientists filmed 25 dogs of various breeds as they observed their owners and strangers either yawning or making other mouth movements; they also monitored the dogs’ heart rates throughout the experiment. All the canines responded more to their owners’ genuine yawns than to those of strangers, as the poodle, Kikumaru, is doing above. And none of them had a change in their heartbeats, making it unlikely that their yawns are due to stress. The team concludes that contagious yawning in dogs is emotionally similar to that in humans. And that means, as most dog owners would surely attest, that Fido has some form of rudimentary empathy. Perhaps the next question is, how empathetic are we with other species: Do we yawn when our dog yawns?