Human Yawns Unleash Dog Yawns

Dogs catch yawns from their sound alone, scientist from the Universidade do Porto in Portugal have found. They also catch their owner's yawns easier than those from others, supporting the theory that contagious yawns are empathy-based and emotional in nature, the researchers say.

Previous research has linked contagious yawning to empathy (the ability to understand and interpret another's emotions) in humans. They've shown that people who perform better on empathy-related tasks also contagiously yawned more.