Primate Sex and Its Role in Pleasure, Dominance and Communication

SIMPLE SUMMARY: Sex is inextricably linked to reproduction, but in humans at least it also has many other roles. In the animal kingdom sex has traditionally been considered as having only a reproductive function. However, many animal species regularly engage in sex outside of their fertile period, and homosexual and immature sex are more common than previously thought. This suggests that sex has also an important role outside of reproduction. Is the human sexual experience, which includes pleasure, dominance, and communication, unique, or do other animals also share these experiences to any extent? If so, is there any way to measure them, or are they beyond the rigour of scientific objectivity? What would be the evolutionary implications if human-like sexual experiences were found amongst other animals? In this commentary we attempt to address these questions looking at the evidence from our relatives, non-human primates, and suggest potential methods for measuring some of these experiences empirically. ABSTRACT: Sexual intercourse in the animal kingdom functions to enable reproduction. However, we now know that several species of non-human primates regularly engage in sex outside of the times when conception is possible. In addition, homosexual and immature sex are not as uncommon as were once believed. This suggests that sex also has important functions outside of reproduction, yet these are rarely discussed in sex-related teaching and research activities concerning primate behaviour. Is the human sexual experience, which includes pleasure, dominance, and communication (among others) unique, or do other primates also share these experiences to any extent? If so, is there any way to measure them, or are they beyond the rigour of scientific objectivity? What would be the evolutionary implications if human-like sexual experiences were found amongst other animals too? We comment on the evidence provided by our close relatives, non-human primates, discuss the affective and social functions of sex, and suggest potential methods for measuring some of these experiences empirically. We hope that this piece may foster the discussion among academics and change the way we think about, teach and research primate sex.