• Extended female sexuality

    Extended female sexuality

    • Extended female sexuality is where the female of a species mates when infertile. In most species, the female only engages in copulation when she is fertile. However, extended sexuality has been documented in old world primates, pair bonded birds and some insects (such as carrion beetles). Extended sexuality is most prominent in human females who exhibit no change in copulation rate across the ovarian cycle. Although this behaviour incurs costs to females, such as energy and time, many researchers have proposed reasons for its existence. These hypotheses include the male assistance hypothesis, which proposes that females gain non-genetic benefits (such as food and shelter) in exchange for sexual access. A sub-hypothesis of this is Hrdy's; proposing extended female sexuality as an adaptive process aiming to creating paternity confusion in males. Alternative hypotheses, classified as 'male-driven', claim that extended female sexuality occurs due to male adaptations, resulting from an inability to detect fertility status in females or to dampen immune responses against sperm. Finally, Spuhler's hypothesis suggests that the behaviour may have arisen as an incidental effect of larger adrenal glands in humans.

      Although not found in all organisms, researchers have identified sexual intercourse patterns in certain animals that reflect extended female sexuality, such as in some old world primates, birds and insects. Extensive research has focused on analysing the musk shrew's rate of sexual behaviour. The only period that is associated with a drop in female receptivity to copulation is during mid to late pregnancy; yet, even at this time, occasional mating is reported. Therefore, researchers have concluded that this animal has similar sexual receptivity across infertile and fertile phases. Within primates, research has consistently found evidence of extended female sexuality in the rhesus monkey and chimpanzees. Both of these primates mate at all stages of the ovarian cycle, with only slight increases in sexual receptivity during fertile stages, and decreases during menstruation.

      • Buss, D. M. (2015). The Handbook of Evolutionary Psychology, Foundation (Chapter 13). New York: John Wiley & Sons.
      • Campbell, L. (2009, June 17). Comparison of the sexuality of humans, common chimpanzees and bonobos. Retrieved from
      • Shackelford, T. K., & Hansen, R. D. (2015). The Evolution of Sexuality (Chapter 8). New York: Springer.
      • Simpson, J. A., & Campbell, L. (2013). The Oxford Handbook of Close Relationships (Chapter 17). Oxford: University Press.
      • Thornhill, R., & Gangestad, S. W. (2008). The Evolutionary Biology of Human Female Sexuality (Chapter 3). Oxford: University Press.
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    • Extended female sexuality