The Red Queen_ Sex and the Evolution of Human Nature - Matt Ridley [80]
Grant, then, that men prefer women with relatively wide hips and large breasts. That still does not explain the gaining of fat on breasts and hips; fat breasts do not produce more milk than lean ones of the same size, and fat hips are no further apart than lean ones of the same bone structure. Low thinks women who gained fat in those places may have deceived men into thinking they had milk-full breasts and wide hip-bones. Men fell for it, because the cost of distinguishing fat from heavy breasts, or of distinguishing fat from wide hips was just too great and the opportunity to do so has been lacking. Men have counter-attacked, evolutionarily speaking, by ‘demanding’ small waists as proof of the fact that there is little subcutaneous fat, but women have easily overcome this by keeping waists slim even while laying down fat elsewhere. After all, the name for the ratio of breasts and hips to waist is ‘vital statistics’. A woman whose vital statistics are 35–35–35 is overweight, pregnant, or middle-aged. A woman whose vital statistics are 35–22–35 is a candidate for the centrefold of Playboy.65
Low’s theory might not be right, as she is the first to admit, but it is no less logical or far-fetched than any of its rivals, and for our purposes here it serves to demonstrate that a Red Queen race between a dishonest advertiser (in this case, unusually, a female) and a receiver who demands honesty may not always be won by the honesty-demanding gender. It is essential, if Low is right, that fat is cheaper to gain than mammary tissue, just as it is essential, for Dawkins and Guilford, that cheating is cheaper than telling the truth.66
Chucking Frogs
The male’s goal is seduction: he is trying to manipulate the female into falling for his charms, to get inside her head and steer her mind his way. The evolutionary pressure is on him to perfect displays that make her well-disposed towards him and sexually aroused, so that he can be sure of mating.
The evolutionary pressure on a female – assuming she benefits from choosing the best male – is to invent resistance to all but the most charming displays. To say this is merely to rephrase the whole argument of female choice with a greater emphasis on the how than the why. But such rephrasings can be illuminating and this one has proved exceptionally so. Michael Ryan of the University of Texas rephrased the question a few years ago and he did so partly because he studies frogs. It is easy to measure female preferences in frogs because the male sits in one spot calling and the female moves towards the sound of the male she most likes. Ryan replaced the males with loudspeakers and offered each female different kinds of recordings of males to test her preference.
The male tungara frog attracts a female by making a long whine followed by a ‘chuck’ noise. All of its close relatives bar one make the whine but not the chuck. But at least one of the chuckless relatives turns out to prefer calls with chucks to those without. This was rather like discovering that a New Guinea tribesman found women in white wedding dresses more attractive than women dressed in tribal gear. It seems to indicate that the preference for the chuck just happens to exist in the fact that the female’s ear (to be precise, the basillar papillae of the inner ear) is tuned to the chuck’s frequency; the male has, in evolutionary terms, discovered and exploited this. In Ryan’s view, this deals the whole house of female-choice theory a blow. For that theory, whether in Fisher’s sexy-son form or the Good-genes form, predicts that the male’s ornament and the female’s preference for such an ornament will evolve together. Ryan’s result seems to suggest that the preference existed, fully formed, before the male ever had the ornament. Peahens preferred eyed trains a million years ago, when peacocks still looked like big chickens.67
Lest the tungara frog be thought a fluke, a colleague of Ryan’s, Alexandra Basolo, has found exactly the same thing in a fish called the platyfish. Females prefer males who have