Humans have been known to yawn when they witness another person yawning, but animals — particularly primates and dogs — might also yawn contagiously. Some scientists believe that yawning after someone else yawns is a sign of empathy. Although primates such as chimpanzees have been generally found to exhibit contagious yawning only to other chimpanzees with whom they have close relationships, studies have found that dogs might yawn contagiously after seeing humans yawn. Some researchers believe that a possible reason is that the dogs pick up on human social cues and can empathize with humans, particularly their owners. Dogs tend to be more likely to yawn contagiously as they age, and puppies typically do not display the trait of contagious yawning.
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