The Red Queen: Sex and the Evolution of Human Nature

by Matt Ridley

The degree to which an animal of either sex is choosy correlates exactly with the degree to which it invests in parental care. A black grouse, investing no more than sperm, is prepared to copulate with anything that even resembles a female: A stuffed bird or a model will do.40 A male albatross, who will put all his best efforts into raising one female’s young, is elaborately suspicious and selective, striving for the best female on offer. So man’s choosiness reflects once more the fact that man does indeed form a pair bond and invest in his young, unlike some of his undiscriminating ape cousins. It is a legacy of his past monogamy: Choose well, for it may be the only chance you will get. Indeed, the overwhelming fascination of men with female youth argues that pair bonds have lasted lifetimes. In this we are quite unlike any other mammal. Chimpanzees find old females just as attractive as young ones as long as both are in estrus. The fact that men do prefer twenty-year-olds adds one piece of evidence to the theory that a Pleistocene man, like a modern man, married for life.