Besides people and dogs, contagious yawning has been observed in gelada baboons, stump-tail macaques, and chimpanzees. Humans tend to yawn more with friends and acquaintances, suggesting that “catching” someone’s yawn may be tied to feelings of empathy.
Similarly, some studies have found that dogs tend to yawn more after watching familiar people yawning. But it is unclear whether the canine behavior is linked to empathy as it is in people. One clue might be if even the mere sound of a human yawn elicited yawning in dogs.
by Zuberoa Marcos