Four Fascinating Facts About the Evolution of Human Sexuality

Making a definitive statement about the true nature of human sexuality is a dangerous game, as how can we ever truly know what is natural and what is not? One group’s natural may be akin to another group’s wildest dream.

Looking at human sexuality from a historical, social and culture perspective, married authors Christopher Ryan and Cacilda Jetha pose some intriguing questions and offer controversial theories on why we behave the way we do in the bedroom and beyond in their new book Sex at Dawn.

1 – Maybe monogamy isn’t as natural as we’re led to believe it is

Ryan and Jetha reject the Hobbesian view of life in the state of nature as “solitary, poor, nasty, brutish, and short” and offer compelling evidence that up until about 10 000 years ago, tribal people enjoyed a high level of sexual freedom. The nomadic tribal lifestyle depended upon fierce egalitarianism, where sharing was not just encourage but mandatory and they suspect that sharing extended to every aspect of life, including sexual relations.

It was the introduction of agriculture and corresponding importance placed on property ownership that caused paternity to become a concern, leading to monogamous, heterosexual pair-bonding. Of course it didn’t help that the church was espousing commandments like “thou shalt not commit adultery” and “thou shalt not cover thy neighbor’s wife.”

The central argument of their book is that accepting this flawed myth of the origin and nature of human sexuality is ultimately destructive, as it distorts our understanding of our sexual capacities and needs. If monogamy is so natural, the authors wonder, then why has adultery existed in some way, shape or form in every culture throughout history, even under the threat of gorey punishment like being stoned to death.

Furthermore, if the well of love runs deep or even bottomless for family, friends, films, foods, and so on, how can it be true that sexual love is a finite resource?

2 –Extended receptivity is the way to go, just ask the bonobos

Human females are practically unique amongst mammals in that our fertility cycle is concealed, and we engage in sexual activity throughout the duration of our menstrual cycles, not just during ovulation. This is referred to as “extended receptivity” in scientific circles.

We may have evolved this way as a means of males constantly keeping tabs on their women, to ensure paternity, or it may be that women were given the capacity of consistent mating to confuse the men as to whose children were really whose, protecting the fate of the child from the wrath of the jealous alpha.

The only other mammal whose females exhibit this trait is the bonobo ape of central Africa. Bonobos are well-known for their high levels of sexual behavior. They use sex for social purposes like conflict resolution, pleasure and stress reduction, as opposed to chimpanzees and other primates who do it primarily for reproducing. Dutch primatologist Frans de Waal has found that this increased sexual receptivity on the part of the female bonobo leads to dramatically decreased levels of male conflict.

While we often look to the chimpanzee as a mirror in the ape world, maybe we ought to pay equal attention to the bonobo, as our DNA differs from that of both species from a mere 1.6 percent. As Ryan and Jetha point out, this makes us closer to them than an Indian elephant is to an African elephant.

Interestingly enough, monogamy is not a common trait amongst primates either. The lone monogamous ape is the tree-dwelling gibbon, native to Southeast Asia.

3 – Maury would have a field day with this one!

There are societies in the Amazon that view a fetus as an accumulation of semen within an egg. Women in these tribes often seek out a varying assortment of sexual partners in order to pass on a variety of useful skills and traits to their offspring. The Paraguayan Ache tribe, for example, cites four different categories of fathers:

“Miare: the father who put it in;

Periare; the fathers who mixed it;

Momboare; those who spilled it out; and

Bykuare; the fathers who provided the child’s essence”

With more males looking out for them in the tribe, Ache children have a significantly better chance of surviving through childhood than those born into the similar societies with just one recognized father.

 4 – Marriage by any other name might smell as sweet… or sweeter

“’Marriage, mating and love are socially constructed phenomena that have little or no transferable meaning outside any given culture,” write Ryan and Jetha. In fact, there are cultures where the concept of traditional marriage doesn’t even exist, such as the matrilineal Chinese Mosuo tribe. Their language has no word for husband or wife, and the word they use for sexual coupling sese is synonymous with walking. Though this term is often translated by anthropologists as walking marriage, it has very little in common with the fidelity or vows of its Western counterpart.

Mosuo couples do not live together and their relationships exist only within the present. As soon as they are no longer in each other’s physical presence, it comes to an end, though they may visit again in the future. Men and women are encouraged to pursue as many relationships as they wish, and complete discretion is expected from all parties.


So what does this all this mean for the future of monogamy? While we’re definitely a long way off from the sexual freedom of our prehistoric ancestors or their contemporary incarnations like the Mosuo tribe, we’re getting closer to accepting alternatives to monogamy. It may take generations for the stigmas associated with non-monogamy to erode completely, but research like Ryan and Jetha’s is helping us get closer by getting the conversation started.

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