Ever since Galileo argued that the sun was the center of the solar system, the idea of Earth as the universal hub has been the classic example of scientific arrogance. It's certainly a foolproof example of the way humans consider themselves the rule by which everything else should be measured, but when we use it, there's a sense that we don't make that kind of mistake anymore. Yet even today scientists are swayed by the notion that humans stand at the center of the biological universe, especially when it comes to what we care about most: our minds.
Meaningful, communicative gestures are shared by humans and other great apes. As with human groups, different groups of chimpanzees and bonobos may use the same gesture to mean completely different things. New Scientist, The Economist, PNAS.