Our closest relatives, chimps and bonobos, get seriously sexually interested when they see a submissive posture, and especially the sight of a red, hot ass, presented for their attention. In human bdsm, many doms feel the same way about the heat and colour of a disciplined submissive’s ass. So, is some of the force of our sexual response linked to our common hominid ancestry?

This is Vanessa Woods, a primatologist who’s lived with bonobos and contributed a lot to our knowledge of their social structures. She’s not responsible at all for suggesting a connection between bonobos and bdsm.

It’s certainly true that we’re closely related to chimps and bonobos. We evolved from the same ancestors, until the family branch split into homo, which is us, and pan, which is them, about 4 to 6 million years ago. That isn’t as long in evolutionary terms as it is when you’re waiting for a bus. We share about 95% of our DNA with our cousins.  

It’s not just genetics. We have quite a few things in common with them that are, in a sense, cultural, including lots of the ways we show affection, the way we do violence (I mean, like two guys getting angry, not mechanised warfare), and quite a lot about the way we do sex. So it’s completely plausible that we, or some of us, are still in thrall to that ancestral sexual signal. 

But we’re different from chimps and bonobos in two important ways. First, we don’t have a strong sexual cycle like them: chimp and bonobo females mostly only mate when they’re at the peak of their monthly reproductive cycle, so they need to signal when they’re most interested in fucking. Human women can fuck any time. No signal is needed, so it won’t be selected for. 

Second, we walk upright. A sexual signal that works best when the ass is the highest and most prominent point of the body doesn’t work so well when you’re standing. So we humans don’t have that signal.

That’s not the end of the argument, but it’s awkward for the case I’m trying to build. 

But I’ve also run her pic because I’m a fan; I’ve read her book, think she’s brilliant, ridiculously brave, and so on. And, like so many women primatologists, she’s gorgeous.

It’d be nice, really nice, if we knew how recently our ancestors lost that bright red sexual signal. Our ancestors probably had it, say, four million years ago, when we were still separating from chimps and bonobos.

But that’s all we’ll ever know.

We can look at our ancestors’ bones, but sadly, one thing that doesn’t fossilise is asses. All the hominid asses, the ones before homo sapiens sapiens, have rotted away and been eaten by worms, and we’ll never know a damn thing about them. 

But we can make some guesses, some of which don’t seem to be completely stupid, and make the best use of the evidence we do have. That’s tomorrow.