Angela Saini: They may use other members of their own sex. Our aggressive faces are the same with other primates, the more the urge to attack dominates the urge to flee, the more the face pulls itself forwards. Instead, my quarry was old books about nature, anthropology and evolution, and my territory was the dusty shelves of old bookshops. Having been immersed in the same ethological tradition out of which Morris had come, viewing humans this way was no controversial claim. Nudity Why on earth should the haunting ape have become a naked ape? They became more upright-fast, better runners. Only the names have been changed: In the laid-back, blue-smoke atmosphere of the hippy era, the book struck a chord with the wider public — if for no other reason than that, in the decade of free love, it asserted that humans had the largest penis for body size of all the primates. I was the one who broke down the news to my mom, but while I was telling her the terrible news, I found myself smiling! So submissive behavior must be the opposite.