Monkeys. We already know they can wash cats. But did you know they also enjoy a laugh at someone else's expense?
A recent study in the journal Evolution & Human Behavior found that laughter assists in social bonding among primates. In particular, the apes in the study enjoyed slapstick humor. According to the observations of study co-author Robin Dunbar, the apes also played practical jokes on each other and would laugh at another ape's bad luck. Those findings were not included in the study, however.
