Posts

The biology of why guys are obsessed with threesomes

/in , /by

Threesomes. Every man’s fantasy. Personally I’ve never seen the appeal but then again, I’m not a man. I’ve always found it interesting that even though a lot of women have participated in threesomes, very rarely are they participating in a two men/one woman arrangement. It’s almost always two women with one man. Why is that? My guess is that it has to do with our evolution.

You see, humans evolved to be essentially polygamous where one man would have 2, 3, or maybe even more wives depending on his social status and how good of a provider he was. Most indigenous societies around the world function this way and in a lot of ways promiscuity for a man and loyalty to a single partner for a woman makes perfect biological sense.

Our most primitive urge is to procreate and those that are the best procreators are the ones that pass their genes, most successfully, on. We are always, therefore, seeking to be the most effective procrators possible. The best way for men to be good procreators is to have many wives or sleep around a lot (especially if they are saving time by taking the girls 2 or 3 at a go!) Females, on the other hand, are limited in how many babies they can have and so our strategy is to do the best we can to make sure the babies we have stay alive. For women, polygamous life is just practical. With other women around, you have some help with the children and whatever work needs to be done. With them around nobody is ever left alone at home all day with a screaming infant and if you get sick and aren’t able to care for your little one, there is always someone else who can. For this reason I have always suspected that the loss of our tribes is felt most strongly by stay at home moms.

Our primal, polygamous nature is still very much a part of our genetics and its the reason why so many guys are hesitant to tie themselves to just one woman and why, to them, the idea of a threesome is just deliciously tantalising. And likewise, our polygamous nature where many females would have been loyal (for the most part) to a single man is why even those women that could easily attract the attention of a legion of men still generally idealise a romantic union with just one other person.

A lot of my friends are surprised when I tell them that I can really understand the thinking behind the women and also the man in the reality show, “Sister Wives” which centres around a polygamous family in Utah. I can understand how it must be nice for the women to have the company of one another and I respect the man for having an up-front polygamous marriage rather than pulling a Tiger Woods.

Some men are just like gorillas

Coincidently, gorillas are similar to our human ancestors and to the Sister Wives in the way that one male will have a harem of many loyal females.

photo credit: silverback

Men are competing for us even after they have cum and gone (sperm competition in bats and people)

/0 Comments/in , /by

It’s true – even after a man manages to woo us, fend of the competitors and get us into the sack, the job still aint done. At this point he basically just relays the responsibility onto his sperm who continue to compete in what reproductive biologists call a “sperm competition”. For sexually monogamous couples there are no sperm competitions but when a woman cheats on her partner or if she goes on some kind of unprotected Girls Gone Wild SOCal spring break, there can be stiff competition (pun sadly intended) for sperm.

I have just begun research into sperm competition for my master’s degree. I’m studying it in regards to bats. Bats have always been of fascination to me but it wasn’t until I started learning about their sexcapades that I decided to go into major student debt over it!

You see, because many species of bat live in gigantic social groups (sometimes numbering in the hundreds of thousands) there are near unlimited opportunities for them to sleep around (or “hang out” as we Gen-Y’ers call it ..hey maybe we get this term from the bats!). Most bats also don’t believe in monogamy. Only 12 of the over 1,200 species of bat are believed to be monogamous – and with a little genetic testing, I’m convinced it’s even less than that. They tend to live either polygamously or, more commonly, like baboons where any male can mate with any female with the exception of some direct family members. For bats, every day is a SOCal spring break! At least in the breeding season, anyway.

Even more ridiculous, female bats can distend their reproductive tracts to hold huge quantities of semen which they can keep alive in their bodies for up to 200 days!! All of this adds up to a situation where sperm are competing with each other like gang busters.

What happens, then, when the sperm have to compete so much is that natural selection favours males with larger balls (that produce more sperm) in the way that if you want to win a raffle you buy more tickets. Over time, then, bat balls have evolved to absolutely vulgar proportions! In one species, the Rafinesque’s big-eared bat, the combined testes weight is 8.4% of total body weight. That’s the equivalent of a 180lb man walking around with 20lb balls! IT’S INSANITY!!

The craziest part of it, too, is that because bats have to maintain low body weights in order to fly they can’t just carry around these gigantic balls without having to pay for it somewhere else and so not surprisingly – the brains take the hit. They have actually found that the larger the balls of a bat, the smaller the brain*.

I was just thinking about all of this in the shower (as you do) and realised how ridiculous it all is. I mean in an effort to be the winner of the sperm competition, testicles only think to do one thing: produce more sperm. Even if the end result makes them dumber. Does it never occur to them to produce quicker, faster, more efficient sperm and not have to sacrifice grey matter? Nope. Well, sometimes. Occassionally, rather than producing more sperm to win the sperm competition they’ll produce bigger sperm but this really isn’t much better.

And doesn’t this just sum up men perfectly?? I mean the male agenda is always about bigger, better, more. Women on the other hand, understand value. That’s why we produce one perfect, valuable, egg rather than a million crappy ones. Not to mention why we fantasize about one perfect partner instead of a threesome …

*This doesn’t apply to flying foxes

Photo credit