[...]... demonstrates that there was evolutionary maintenance of the glands during the evolutionary history of mammals Some kind of evolutionary mechanism must account for the retention of the glands in the Tree of Life after their appearance Were the glands selected directly, indirectly, or neither? If neither, their retention is explained by drift Given the obvious functional design of the glands—their precision... branches of the Tree of Life comprising Mammalia Had mammary glands not appeared, current mammals would not now possess them Had they not been maintained, however, current mammals likewise would not now possess them The causes of both the origin and maintenance of mammary glands jointly explain their existence today But these causes are themselves distinct 18 The Evolutionary Biology of Human Female Sexuality. .. concealed ovulation, but rather reflect other adaptations We need not expand on these points here; in many ways, the goal of this entire book is to do so For precisely the reason that, in many ways, the purpose of this book is to expand on these themes, however, we do mention these themes here Naturally, a good deal of what we offer describes details of the studies and key findings of the past decade or two... get at least a few things right in the end If we do not, however, we hope that our own efforts assist others who do 12 The Evolutionary Biology of Human Female Sexuality Overview of the Book We analyze four major features of woman’s sexuality using evolutionary methodology Chapter 2 discusses the methods we use, those of adaptationism and phylogenetics Three of the four features we address—continuous... fertility The evolution of woman’s concealed fertility in the menstrual cycle did not involve the evolutionary loss of signals of cycle-related fertility Rather, by-products of female peak fertility that males were selected to detect were disguised by selection on females during the evolution of woman’s concealed fertility We suggest that the slight sexual ornamentation that the earliest females in the human. .. Concealed Fertility 266 12 Coevolutionary Processes: Men’s Counterstrategies and Women’s Responses to Them 290 13 Reflections References Index 393 331 321 The Evolutionary Biology of Human Female Sexuality This page intentionally left blank 1 Background and Overview of the Book An Abridged History of the Study of Woman’s Sexuality “I should say that the majority of women (happily for them) are not very much... increasingly aware of the ways by which intersexual conflict fuels antagonistic coevolution of the sexes In so doing, they more fully incorporated Hrdy’s view of female sexuality being strategic and situation dependent Estrus Redux The scientific investigation of women’s sexuality has a noble history The dedicated pursuit of the truth of women’s sexual design and the phylogenetic origin of the design is... primate female sexuality (and multiple mating) cannot be understood solely in terms of its direct reproductive effects on number of conceptions and thereby offspring number; rather, its effects on female reproductive success must be partly understood in terms of its effects on the survival and well-being of individual offspring (1981) Specifically, she proposed that langur females and females of many other... emphasized the important role of female choice in evolution (Bajema, 1984, p 150) Yet more than a century would pass before Darwin’s claim that female choice is a salient evolutionary force was vindicated and became widely accepted in evolutionary biology this did not occur until the past few decades, supported by literally hundreds of empirical 3 4 The Evolutionary Biology of Human Female Sexuality. .. disguise of fertility cues that has actively been selected—must be distinguished from “undisclosed estrus,” the lack of overt cues of fertility status resulting simply from lack of active selection for them We propose, in an extension of the cuckoldry hypothesis of Benshoof and Thornhill (1979) and Symons (1979), that, in human evolutionary history, the importance to female reproductive success of securing . alt="" The Evolutionary Biology of Human Female Sexuality Randy Thornhill and Steven W. Gangestad This page intentionally left blank 1 2008 The Evolutionary Biology of Human Female Sexuality Randy. supported by literally hundreds of empirical 4 The Evolutionary Biology of Human Female Sexuality documentations of female choice and male adaptations to impress choosy females in many animal taxa. demonstrated in nonhuman female mammals. In the 1930s, these hypotheses guided psychological investigations, the  rst of their kind, of patterns of women’s sexual behavior across the menstrual