A fun article in today’s New York Times about chimpanzee cooperation.
A key paragraph: “In one series of experiments, Dr. Hare, Alicia P. Melis and Michael Tomasello placed an adult chimpanzee in a cage, outside of which was a plank with food on it. It was possible to get the food by pulling on two ropes. In some trials, the ropes were too far apart for one chimpanzee to get the food on its own. The chimpanzee could get help by opening the door of an adjoining cage where another chimpanzee was waiting.”
As the saying goes, read the whole thing!