Orangutan communication works just like a game of charades, according to new research. Orangs and other apes who use signals to communicate what they want pay careful attention to whether their audience understands their gestures—if something works, they repeat it, and if they aren't getting through they try another signal.
The experiment tested the apes by using a desirable food—bananas—and bland foods—leeks and celery. If the orang made a gesture to the keeper and got half a banana, it would repeat it with extra emphasis to get the second half. If the faux-naive keeper handed over a leek, the ape would reach into its repertoire for a new signal. Scientists say the smart simians probably evolved the mime skills millions of years ago.