But strip that veneer away and genetic imperatives can reassert themselves with frightening force. A salutary example, discussed by Ridley, concerns the fate of the early Pitcairn Islanders. The nine mutineers from the Bounty settled the island with six male and 13 female Polynesians. Eighteen years later when the colony was rediscovered, only one man survived along with a harem of 10 women. Twelve of the men had been murdered in an orgy of violence prompted by sexual competition.
Human behaviour is placed in context by studying the sexual activities of other animals.
Some birds, such as the albatross, are strictly monogamous, while others like the sage grouse are polygamous. More light is shed on sexual behaviour by a branch of mathematics called game theory. Consider the choices facing a young female. Joining a powerful male's harem offers resources that help her young survive, but she has to share those resources with others. Bonding to a monogamous male and enlisting his exclusive help in rearing the young offers an alternative.