Book Summaries health

Chapter 5: The Peacock’s Tale (The Red Queen)

Every female animal wants a mate with sufficient genetic quality to make a good husband and good father. Every male animal wants as many wives as possible, and to sometimes find good mothers and dams – rarely to find good wives.

Genetic Sieves

Males act as a kind of genetic sieve: only the best males get to breed and the constant reproductive extinction of bad males constantly purges bad genes from the population.

It has sometimes been suggested that this is the ‘purpose’ of males but that falsely assumes that evolution designs what is best for the species.

Samuel Butler, ‘ a hen is only an egg’s way of making another egg’,

In choosing mates, males are after quantity, while females are after quality. The peacock male will go through their ritual courtship display for any passing female; females will mate with only one male, usually the one with the most elaborately decorated tail. It is the female’s fault that the male has such a ridiculous tale, according to sexual selection theory.

Females evolved the ability to be charmed to be sure of picking the best males.

Darwin suggested that peacocks have long tails (they are elongated rump feathers that cover the tail) because peahens will only mate with peacocks that have long tails. Since then, the peacock has been the mascot of sexual selection.

But what is the explanation behind this? Is it competition between males that determine aesthetic characteristics or is it simply innate female choice?

There are two techniques – wooing or winning – both are equally likely to sieve out the ‘best’ male.

The difference is that whereas the first technique will select dandies, the second will select bruisers. Thus bull elephant seals and red deer stags are big, armed and dangerous. Peacocks and nightingales are aesthetic show-offs.

Experiments have shown that females choose. And female preference for male ornaments can be a threat to the survival of the males.

Females choose; their choosiness is inherited; they prefer exaggerated ornaments; exaggerated ornaments are a burden to males. That much is now uncontroversial. So far, Darwin was right.

Mimetic Females

In the 1970s, Fisher suggested that females prefer long tails simply because other females also prefer long tails. This sexy-son reason suggests that peahens prefer beautiful males because they seek heritable beauty to pass on to their sons, so that their sons could attract females.

A competing theory is the one based on good-genes: peahens want beautiful males because beauty is a sign of good genetic qualities – disease resistance, vigor, strength, and these are qualities that females want to pass down to their sons.

A mutation in a gene will make an ornament smaller, and less colorful. Mathematicians think that this mutational bias is sufficient for females to choose an ornamented male, because by doing so, she is choosing the male with fewest mutations.

The result, then, of a decade of mathematical games has been to prove that the Fisherians are not wrong. Arbitrary ornaments can grow elaborate for no other reason than that females discriminate between males and end up following arbitrary fashions; and the more they discriminate, the more elaborate the ornaments become.

If you look around, you will see that the ornaments that exist are truly arbitrary – whether peacock’s eyes, sage’s air sacs, or the melodies of nightingales. There is nothing indicative or vigor – if there was, the ornaments we see would not be so random.


Advertisers don’t sell their product by giving people information about it. they exaggerate and try to associate whatever they are selling with pleasurable feelings and images. They sell ice cream using sexy pictures, and cigarettes using cowboys. When a man seduces a woman, he does not send her a picture of his bank statement, but a pearl necklace. He does not show her a report from his doctor, but mentions that he runs ten miles a week and never gets sick. He doesn’t tell her about his university degrees but dazzles her with wit. Each gesture has a message.: I’m rich, I’m fit, I’m clever, I’m nice.

In courtship, as in the world of advertising, there is a discrepancy of interests between the buyer and the seller. The female needs to know the truth about the male: his health, wealth and genes. The male wants to exaggerate and distort the information. The female wants the truth; the male wants to lie.

Matt Ridley, The Red Queen

"Silence is the best expression of scorn" - G.B. Shaw

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