Juvenile chimps yawn contagiously when they see humans do it, a response that could signal the animals are developing empathy.
Scientists yawned and wiped their noses in front of 12 infant and 21 juvenile chimpanzees kept in a sanctuary and found that the older animals parroted back the yawns but not the nose-wiping behavior. The infant chimps did not mirror either of the gestures.
Yawning in response to others may be an empathetic response, which is what led Elainie Madsen and colleagues from Lund University to conclude October 16 in PLOS ONE that the juvenile chimps' behavior could be a sign that they are gradually developing empathy during their first years of life.
Other than humans, scientists have only seen this cross-species spread and slow development of yawns in dogs.
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