I was observing a nine-year-old male baboon in the Serengeti of East Africa one day in 1983. Baboon troops are very hierarchical, and this baboon was a familiar type – a young macho bruiser on the way up, intent on toppling the alpha male.

But the alpha male, busy grooming a young female, paid little heed as his challenger threw threatening eyebrow flashes and bared his canines. It was only when the younger baboon got even closer, making guttural vocalisations and slapping the ground, that the alpha stopped and stared at his antagonist for a tension-filled moment. Then the alpha went back to grooming, paying no attention to the histrionics, leaving his challenger to stomp away in frustration.