When Did Sex Become Fun?

As a spiecies we enjoy speculating on the big questions such as where do we come from: early hominins, monkeys, primordial goo or the Big Bang, to name a few starting points. The more eclectic of you may also stray to more risque side of the speculation - sexual intercourse. And, if you think back to the beginning, hundreds of millions of years before we invented euphemisms and censorship, and let’s ask: How in the evolutionary world did sex begin? The answer is almost 2 billion years ago. But after the origins of sex, it took another 1.5 billion years for sexual intercourse—as we vertebrates know it—to come about. The kind of reproductive sex that humans and other mammals, as well as some birds, reptiles, amphibians, and fish, have—with an external male penetrating organ and an internal female reception area—the seemingly dependable but deceptively complex process of internal fertilization is nearly 400 million years old.

In a recent article the online anthropology magazine SAPIENS discusses how actually, as long as it enables successful reproduction, copulation only needs to be rewarding for one of the mating pair—on condition that one partner is able to manipulate its mate into copulating. Maybe this reward system arose early in the evolution of internal fertilization (like even before penetrating genitalia evolved). Now, what about pleasure?