Human laugh lines traced back to ape ancestors

Playing chimps’ facial expressions signal that mirthful communication evolved early on

chimps laughing

LAUGH IT UP  Chimps at play make laughlike, open-mouth faces, whether or not they’re laughing out loud, a new study finds. That means that humans’ versatile communication with open-mouth expressions may have its origins in an ancient ape ancestor, researchers say.

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Laughter’s evolutionary story may be written on chimpanzees’ faces.