The Queen - Matt Ridley

THE BASTARD BIRDS

Compared to our ape cousins, we, the most common of the great apes, have pulled off a surprising trick. We have somehow reinvented monogamy and paternal care without losing the habit of living in large multimale groups: Like gibbons, men marry women singly and help them to rear their young, confident of paternity, but like chimpanzees, those women live in societies where they have continual contact with other men: There is no parallel for this among apes. It is my contention, however, that there is a close parallel among birds: Many birds live in colonies but mate monogamously within the colony: And the bird parallel brings an altogether different explanation for females to be interested in sexual variety. A female human being does not have to share her sexual favors with many males to prevent infanticide, but she may have a good reason to share them with one well-chosen male apart from her husband.

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This is because her husband is, almost by definition, usually not the best male there is—else how would he have ended up married to her? His value is that he is monogamous and will therefore not divide his child-rearing effort among several families. But why accept his genes? Why not have his parental care and some other male ' s genes?

In describing the human mating system, it is hard to be precise. People are immensely flexible in their habits, depending on their racial origin, religion, wealth, and ecology: Nonetheless, some universal features stand out: First, women most commonly seek monogamous marriage—even in societies that allow polygamy.

Rare exceptions notwithstanding, they want to choose carefully and then, as long as he remains worthy, monopolize a man for life, gain his assistance in rearing the children, and perhaps even die with him. Second, women do not seek sexual variety per se. There are exceptions, of course, but fictional and real women regularly deny that nymphomania holds any attraction for them, and there is no reason to disbelieve them. The temptress interested in a one-night stand with a man whose name she does not know is a fantasy fed by male pornography: Lesbians, free of constraints imposed by male nature, do not suddenly indulge in sexual promiscuity; on the contrary, they are remarkably monogamous: None of this is surprising: Female animals gain little from sexual opportunism, for their reproductive ability is limited not by how many males they mate with but how long it takes to bear, offspring. In this respect men and women are very different.

But third, women are sometimes unfaithful. Not all adultery is caused by men. Though she may rarely or never be interested in casual sex with a male prostitute or a stranger, a woman, in life as in soap operas, is perfectly capable of accepting or provoking an offer of an affair with one man whom she knows, even if she is

" happily " married at the time. This is a paradox. It can be resolved in one of three ways. We can blame adultery on men, asserting that the persuasive powers of seducers will always win some hearts, even the most reluctant. Call this the " Dangerous Liaisons " explanation.

Or we can blame it on modern society and say that the frustrations MONOGAMY AND THE NATURE OF WOMEN

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and complexities of modern life, of unhappy marriages and so on, have upset the natural pattern and introduced an alien habit into human females. Call this the "Dallas " explanation. Or we can suggest that there is some valid biological reason for seeking sex outside marriage without abandoning the marriage—some instinct in women not to deny themselves the option of a sexual "plan B"

when plan A does not work out so well. Call this the "Emma Bovary " strategy:

I am going to argue in this chapter that adultery may have played a big part in shaping human society because there have often been advantages to both sexes from within a monogamous marriage in seeking alternative sexual partners. This conclusion is based on studies of human society, both modern and tribal, and on comparisons with apes and birds. By describing adultery as a force that shaped our mating system, I am not "justifying" it. Nothing is more " natural" than people evolving the tendency to object to being cuckolded or cheated on, so if my analysis were to be interpreted as justifying adultery, it would be even more obviously interpreted as justifying the social and legal mechanisms for discouraging adultery: What I am claiming is that adultery and its disapproval are both "natural: "

In the 1970s, Roger Short, a British biologist who later moved to Australia, noticed something peculiar about ape anatomy.

Chimpanzees have gigantic testicles; gorillas have minuscule ones.

Although gorillas are four times the weight of chimps, chimps' testicles weigh four times as much as gorillas'. Short wondered why that was and suggested that it might have something to do with the mating system. According to Short, the bigger the testicles, the more polygamous the females. 1z

The reason is easy to see. If a female animal mates with several males, then the sperm from each male competes to reach her eggs first; the best way for a male to bias the race in his favor is CO

produce more sperm and swamp the competition. (There are other ways. Some male damsel flies use their penis to scoop out sperm that was there first; male dogs and Australian hopping mice both

" lock " their penis into the female after copulation and cannot free

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it for some time, thus preventing others from having a go; male human beings seem to produce large numbers of defective

" kamikaze" sperm that form a sort of plug that closes the vaginal door to later entrants.)" As we have seen, chimpanzees live in groups where several males may share a female, and therefore there is a premium on the ability to ejaculate often and voluminously—

he who does so has the best chance of being the father. This conjecture holds up across all the monkeys and across all rodents. The more they can be sure of sexual monopoly, as the gorilla can, the smaller their testes; the more they live in multimale promiscuous groups, the larger their testes."

It began to look as if Short had stumbled on an anatomical clue to a species' mating system: Big testicles equals polygamous females: Could it be used to predict the mating system of species that had not been studied? For example, very little is known about the societies of dolphins and whales, but a good deal is known of their anatomy, thanks to whaling: They all have enormous testicles, even allowing for their size: The testicles of a right whale weigh more than a ton and account for 2 percent of its body weight. So, given the monkey pattern, it is reasonable to predict that female whales and dolphins are mostly not monogamous but will mate with several males: As far as is known, this is the case. The mating system of the bottle-nosed dolphin seems to consist of forcible

"herding" of fertile females by shifting coalitions of males and sometimes even the simultaneous impregnation of such a female by two males at the same time—a case of sperm competition more severe than anything in the chimpanzee world." Sperm whales, which live in harems like gorillas, have comparatively smaller testicles; one male has a monopoly over his harem and has no sperm competitors.

Let us now apply this prediction to man. For an ape, man 's testicles are medium-sized—considerably bigger than a gorilla 's.

Like a chimpanzee 's, human testicles are housed in a scrotum that hangs outside the body where it keeps the sperm that have already been produced cool, therefore increasing their shelf life, as it were.'

This is all evidence of sperm competition in man: MONOGAMY AND THE NATURE OF WOMEN