Laugh and the whole world laughs with you. Yawn, and so will your dog.
A recent study published in the journal Biology Letters found dogs yawn when humans do, suggesting that canines may have the capacity for empathy.
In their experiment, researchers from the University of London yawned at 29 dogs. 72 percent yawned back—a higher frequency than humans, who typically mimic a yawn 45 to 60 percent of the time.
When the researchers simply opened their mouths wide, no dogs yawned.
Other animals capable of such "facial mimicry" — imitating facial expressions — include orangutans and chimps. Researchers believe that facial mimicry is a rudimentary form of empathy. Studies have found that humans who are more susceptible to contagious yawning score higher on tests that measure empathy.