Gorillas beat their chests to size each other up, researchers say

  Chest-beating behaviour in male gorillas allows them to signal their size and avoid fights with larger rivals It is a trope used in films from King Kong to Tarzan – a male primate standing upright and beating its chest, sometimes with a yell and often with more than a dash of hubris. But it seems the pounding action is less about misplaced bravado than Hollywood would suggest: researchers studying adult male mountain gorillas say that while chest-beating might be done to show off, it also provides honest information. Continue reading... .. Full story on theguardian.com