Can Evolutionary Biology Reveal What's Kinky? (Op-Ed)
A pair of vampire bats caught mating.
Credit: Michael Lynch | Shutterstock

Marc Bekoff, emeritus professor at the University of Colorado, Boulder, is one of the world's pioneering cognitive ethologists, a Guggenheim Fellow, and co-founder with Jane Goodall of Ethologists for the Ethical Treatment of Animals. Bekoff's latest book is Why Dogs Hump and Bees Get Depressed (New World Library, 2013). This Op-Ed is adapted from one that appeared in Bekoff's column Animal Emotions in Psychology Today. He contributed this article to Live Science's Expert Voices: Op-Ed & Insights.

Biologist Carin Bondar recently delivered a phenomenal and learned TED talk called "The Birds And The Bees Are Just the Beginning," an exploration of sexual behavior in a wide variety of nonhuman animals.

Her tongue-in-cheek style is engaging (clearly she enjoys what she does) but she isn't kidding when noting that if people only studied birds and bees , we'd lose a ton of interesting information about the sex lives of other animals — many unfamiliar to me.

One size doesn't fit all

The essence of Bondar's presentation is that there is a lot of diversity in sexual behavior and anatomy among nonhuman animals (animals) and that "one-size-fits-all" explanations don't work.

For example, she explains that paper nautilus males have a detachable, swimming penis that once was thought to be a distinct organism, rather than an organ. The roving swimming penis finds females using pheromones (chemicals). Some of the nautilus penises are huge beyond imagination when scaled to the size of the male's body — though elsewhere in the talk, Bondar points out that vaginas and clitorises also come in a wide variety of shapes and sizes in the animal kingdom. [The 9 Weirdest Animal Penises ]

Bondar also reveals that bed bug sex is incredibly traumatic because of the male's barbed penis , which he may stab anywhere on the female's body to impregnate her. He goes from flaccid to ejaculation in less than one second. I wonder what Alfred Kinsey would have thought about all of this?

I've long been interested in the evolution of different aspects of social behavior in animals, a topic that I cover in my recent book "Why Dogs Hump and Bees Get Depressed." As I listened to Bondar I wondered if evolutionary biology could shed light on what some people consider to be "kinky," loosely defined as some form of unusual or unconventional sex that is considered to be abnormal (and embarrassing). I immediately thought that perhaps people really don't know what is unusual or unconventional because surveys about human sexual behavior may be replete with inaccurate reports of what people really do in bed, on couches, in telephone booths or on kitchen counters.

A web search confirmed my suspicion that sex surveys may not actually tell us what people consider conventional or kinky, or what their intimate lives truly are like.

You drive me batty!

It's clear that other animals aren't as inhibited as humans when they want to get it on in one way or another. After watching Bondar's talk, I thought about oral sex in animals, something that I can't recall having crossed my mind even after having watched thousands of interactions in dogs, coyotes and wolves in which a good deal of attention — both sniffing and licking — is paid to another individual's genital area. I wondered if we're the only animals who engage in fellatio or cunnilingus. So, I did a web search for "oral sex in nonhuman animals" and I found more than 13 million hits! Once again there are problems with the definition, because people define oral sex differently, ranging from oral-genital contact to stimulation that feels good to stimulation resulting in orgasm. Regardless, it's pretty clear that oral sex involves a mouth.

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What I found about the animal kingdom was interesting and new to me. There have been observations of oral sex among nonhuman primates including baboons and bonobos. Bats, too, do it . In fruit-eating Indian flying foxes, cunnilingus as foreplay is a major part of their sexual repertoire and that it lengthens their sex sessions. Males get about an extra two seconds of penetration if they perform cunnilingus for 15 seconds before entering the female.

In the short-nosed fruit, bat fellatio has been observed even during copulation. I wonder if these examples of oral sex in bats are where the phrase, "You drive me batty" (where batty means insane or crazy) comes from? Is it rooted in evolutionary biology?

Is it kinky or not?

Depending on one's take on what's kinky or not, oral sex is unconventionally kinky or "yucky" or normal sexual behavior. If one wants to look to evolutionary biology to tell us what's kinky or not, it's clear there's a lot of what we would call "kinkiness" among nonhuman animals, so for something to be really kinky it would have to be an act that goes beyond standard ranges of imagination. Humans have pretty narrow definitions of sex when compared to other animals.

So, yes, I think evolutionary biology can help us understand what's kinky and what's not. I think of the bumper sticker for evolutionary continuity to go something like, "If we have or do something, 'they' (other animals) have it or do it too."

And, judging from the incredible variability and broad range of sexual behavior among nonhuman animals for which Bondar's lecture gave us but a small taste, you better get ready for a wild ride if you are going to outdo what we know about the sex lives of the fascinating animals with whom we share different niches on our magnificent planet. We can learn a lot from them, but I'm not sure the reverse is true.

Bekoff's most recent Op-Ed was "Science Suggests 'The Dog' Doesn't Exist" This article was primarily adapted from the post "Can Evolutionary Biology Tell Us What's Kinky?"in Psychology Today. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.