those suggesting the exact opposite: The first kind of argument went as follows: Because he does not know when his wife is fertile, a husband must stay around and have sex with her often to be sure of fathering her children. This keeps him from mischief and ensures he is still around to help rear the babies.'
The second kind of argument went this way: If females wish to be discriminating in their choice of partner, it makes little sense to advertise their ovulation. Conspicuous ovulation will have the effect of attracting several males, who will either fight over the right to fertilize her, or share her. If a female wishes (is designed) to be promiscuous in order to share paternity, as chimps do, or if she wishes to set up a competition so that the best male wins her, as buffalo and elephant seals do, then it pays to advertise the moment of ovulation. But if she wishes to choose one mate herself for whatever reason, then she should keep it secret.'
This idea has several variants. Sarah Hrdy proposed that silent ovulation helps prevent infanticide because neither the hus-
band nor the lover knows if he has been cuckolded: Donald Symons thinks women use perpetual sexual availability to seduce philanderers in exchange for gifts. L. Benshoof and Randy Thornhill suggested that concealed ovulation allows a woman to mate with a superior man by stealth without deserting or alerting her husband.
If, as seems possible, ovulation is less concealed from her (or her unconscious) than it is from him, then it would help her make each extramarital liaison more rewarding since she is more likely to
' know' when to have sex with her lover, whereas her husband does not know when she is fertile. In other words, silent ovulation is a weapon in the adultery game.'
This intriguingly sets up the possibility of an arms race between wives and mistresses: Genes for concealed ovulation make both adultery and fidelity easier. It is a peculiar thought, and there is at present no way of knowing if it is right, but it throws into stark contrast the fact that there can be no genetic feminine soli-darity. Women will often be competing with women: SPARROW FIGHTS
It is this competition between females that provides the final clue to the reason adultery, rather than polygamy, has probably been the most common way for men to have many mates. Red-winged blackbirds, which nest in marshes in Canada, are polygamous; the males with the best territories each attract several females to nest in them. But the males with the biggest harems are also the most successful adulterers, fathering the most babies in their neighbors ' territories, too. Which raises the question of why the males ' lovers do not simply become extra wives.
There is a small owl called Tengmalm ' s owl that lives in Finnish forests. In years when mice are abundant, some of the male owls have two mates, one in each of two territories, while other males go without a mate at all: The females that are married to polygamous males rear noticeably fewer young than the females married to monogamous males, so why do they put up with it?
MONOGAMY AND THE NATURE OF WOMEN
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Why not leave for one of the nearby bachelors? A Finnish biologist believes that the polygamists are deceiving their victims: The females judge potential suitors by how many mice they can catch to feed them during courtship. In a good year for mice a male can catch so many mice that Ire can simultaneously give two females the impression that he is a fine male; he can provide each with more mice than he could catch for one in a normal year. 36
Nordic forests seem to be full of deceitful adulterers, for a similar habit by a deceptively innocent-looking little bird led to a
Some male pied flycatchers in the forests of
It is not clear, therefore, whether the wife or the mistress is the victim of treachery, but one thing is certain: The bigamous male pied flycatcher has pulled off a minor triumph, fathering two broods in one season. The male has fulfilled his ambition of bigamy at the expense of a female: The wife and the mistress would both have done better had each monopolized a male rather than shared him.
To test the suggestion that it is better to cuckold a faithful husband than leave him to become the second wife of a biga-
mist, Jose Veiga studied house sparrows breeding in a colony in Madrid: Only about 10 percent of the males in the colony were polygamous: By selectively removing certain males and females he tested various theories about why more males did not have multiple wives: First, he rejected the notion that males were indispens-able to the rearing of young. Females in bigamous marriages reared as many young as those in monogamous ones, though they had to work harder. Second, by removing some males and observing which males the widows chose to remarry, he rejected the idea that females preferred to mate with unmated males; they were happy to choose already mated males and to reject bachelors.
Third, he rejected the idea that males could not find spare females; 28 percent of males remated with a female who had not bred in the previous year: Then he tried putting nest boxes closer together to make it easier for the male to guard two at once; he found that it entirely failed to increase the amount of polygamy.
That left him with one explanation for the rarity of polygamy in sparrows: The senior wives do not stand for it. Just as male birds guard their mates, so female birds chase away and harass their husbands ' chosen second fiancees. Caged females are attacked by mated female sparrows: They do so presumably because even though they could rear the chicks on their own, it is a great deal easier with the husband 's undivided help. 38
It is my contention that man is just like an ibis or a swallow or a sparrow in several key respects. He lives in large colonies.
Males compete with one another for places in a pecking order.
