A baby lowland gorilla rides on his mother's back at the primate sanctuary run by the
Cameroon Wildlife Aid Fund in Mefou National Park, just outside the capital Yaounde.
... 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. No other apes have been seen modifying their signals for infants, although rhesus macaques do change one call when directing it at infants. But Luëf suspects that all great apes can do it. The adults could be encouraging the infants to develop their gesturing, says Richard Byrne of the University of St Andrews, UK. Gorillas have to learn how best to use their repertoire of gestures. That takes practice, and possibly help from older gorillas. "I think it's very likely that's what's going on," Byrne says.American Journal of Primatology via New Scientist