Sexual Selection, Paternal Care, and Concealed Ovulation in Humans

Changes in the social structure of early humans greatly enhanced the potential for paternal care to contribute to offspring success. Selection therefore favored females who mated with more paternal males. Since paternal care limits mating effort, males least successful as polygynists would have the most to gain by paternal behavior, while the successful polygynists would gain least. Concealed ovulation may have evolved because it promoted the paternal tendencies of the less polygynous males who advanced female reproductive success the most. Since the offspring of indulgent males would have a competitive advantage over the offspring of more polygynous males, and females revealing the time of ovulation would become increasingly scarce, all males would eventually pursue a reproductive strategy emphasizing paternal effort over mating effort. In nonhuman primates the most polygynous males mate selectively with females who are likely to be ovulating. Sueh males would probably not mate with females having dhninished cues to the time of ovulation. The more paternally prone males could therefore consort with these females and experience a high confidence of paternity. Another characteristic of nonhuman primates is that the most successful polygynists tend to have a high dominance rank. Thus, female hominlds who mated with more paternal males may have sacrlflced having offspring with some of the gene& advantages that contribute to dominance. However, subconscious physiological and psychological correlates of ovulation in humans may have tempted females to exploit infrequent, lowrisk opportunities to mate outside the pair-bond with males of superior genetic fitness. These correlates may also promote conception irrespective of mating partner, or they may have helped females avoid rape.