"Do you want to play wiv mummy? Wocka-wocka-woo?" said the gorilla. Well, not quite, but older gorillas have been found to use a modified system of gestures when communicating with infants. Much like "motherese", the baby talk human parents use when talking to their children, the gorillas' special gestures may help the infants to develop their own communication skills.
Eva Maria Luëf and Katja Liebal of the Free University of Berlin in Germany monitored 24 captive lowland gorillas (Gorilla gorilla) for four months, focusing on the gestures they used to start and stop play. Typically, gorillas might encourage play by slapping others while making a "play face", for instance, or somersaulting, and end bouts by placing a hand on the other gorilla's head. With infants, every older gorilla used more touch-based gestures and repeated their gestures more.