Imo was a primate genius, an Archimedes or an Edison among the macaques. Her inventions spread slowly; macaque society, like traditional human societies, is very conservative. … As is usually true, adult males were the slowest to catch on, obstinate to the last; a female invented the process, other females copied her, and then it was taken up by youngsters of both sexes. Eventually, infants learned it at their mother’s knee. The reluctance of the adult males must tell us something. They are fiercely competitive and hierarchy-ridden. They are not much given to friendships or even to alliances. Perhaps they felt impending humiliation–if they were to imitate Imo, they would be following her lead, becoming in some sense subservient to her, and thereby losing dominance status. They would rather eat sand.