Chimps Shake Heads 'No'

Saying “no” by shaking our heads back and forth may just be a habit we inherited from our evolutionary precursors. Researchers have filmed Bonobo chimps at the Leipzig Zoo shaking their heads in much the same way, the BBC reports. In one film, for example, a mother shakes her head to indicate her disapproval as her infant plays with its food.

“In Bonobos, our observations are the first reported use of preventive head-shaking,” says one researcher. Bonobos are already known to use head gestures to communicate, but this is the first time they've been caught on film using the head shake. Researchers say it may be a “primitive precursor of the human 'no head-shake.” But they warned that even among humans, the gesture isn't universal; in Bulgaria, head-shaking can mean yes. (More chimpanzees stories.)