Researchers discover that great apes play pranks on each other. Like teasing behavior in humans, ape teasing is provocative, persistent, and includes elements of surprise and play.
This playful teasing occurs in all four species of great apes: orangutans, chimpanzees, bonobos and gorillas. The presence of playful teasing in the four great apes and its similarities with playful teasing and teasing in human babies suggests that playful teasing may have been present in our last ancestor, at least 13 million years ago.