Report, if you have a problem with this page“ ...two chimpanzees were observed maltreating a chicken: One would extend some food to the fowl, encouraging it to approach; whereupon the other would thrust at it with a piece of wire it had concealed behind its back. The chicken would retreat but soon allow itself to approach once again--and be beaten once again. Here is a fine combination of behavior sometimes thought to be uniquely human: cooperation, planning a future course of action, deception and cruelty. ”
Carl Sagan
From : Dragons of Eden: Speculations on the Evolution of Human Intelligence
