Image by Hulton Archive/Getty Images

Earlier this week, Esquire published an article about a new study that seeks to solve an age old mystery: What happened to our penis bones? Yes, even though some of us call erections “boners,” humans do not have penis bones, also known as bacula.

The study, published in Proceedings of the Royal Society, examined the relationship between a species‘ penis bone size and their relative promiscuity. The researchers found that the more promiscuous a species, the bigger the penis bone (reminder guys: humans don’t have penis bones, and evolution takes a long time to work – promiscuity won’t help you out down there).

According to an article on the same subject from The Economist, when a species is more promiscuous, there is a higher chance that a female may be “inseminated by another male before the first male’s spermatozoa have had a chance to fertilize the female’s eggs.” Researchers hypothesize that penis bones act as a means of defending against this reproductive competition.

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So why did human’s lose them? Well, “monogamy became the primary means of reproduction among humans 1.9 million years ago,” Sammy Nickalls at Esquire writes. Without the need to beat out reproductive competition, our penis bones simply shrank out of existence.

But hold on, not so fast “science,” there’s another theory in town. Professor Ziony Zevit of the American Jewish University in Maryland has been thinking about penis bones for quite some time. According to an essay published by Professor Zevit in the journal of the Biblical Archaeology Society, it’s not evolution (who ever heard of such a thing!) we have to blame for our lack of penis bone, but God. You see, all those stories you’ve heard about God creating Eve out of Adam’s rib bone have been sorely mistranslated. Really, Eve was created out of Adam’s penis bone – really. (Though Professor Zevit’s essay appeared in 2015, this debate has been raging on Religiousforums.com since early 2011).

Professor Zevit cites as “evidence” that the Hebrew word for “rib,” “tsela,” appears 40 times in the bible, but is only used to mean “rib” in the context of the story of Adam and Eve. Elsewhere, “tsela” translates to something along the lines of “side,” as in, the side of a building, or a side chamber (which sounds a lot like what ribs are, but hey, I’m no expert). Professor Zevit believes that “tsela” always refers to something that juts out from the center, and you know what juts out from the center? Penises. As further “evidence,” Professor Zevit cites the entirely false idea that men, as opposed to women, have an even number of ribs, which is somehow pertinent, though I can’t figure out why.

Humans are not alone in the world of boneless penises – many types of mammals, like ungulates (deer, cows), marsupials (kangaroos, koalas), and lagomorphs (rabbits), don’t have bacula (though most male mammals do have penis bones). Among primates however, only humans and spider monkeys are lacking the baculum. “Why don’t spider monkeys have penis bones?” you might ask. Well, let me answer your question with another question: Where did all the female spider monkeys come from?

Jake Romm is the Forward’s culture intern. Contact him at [email protected] or on Twitter, @JakeRomm

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