Lack of Penis Bone In Humans Linked To Monogamous Relationships and Quick Sex, Study Says (theguardian.com)

The penis bone can be as long as a finger in a monkey and two feet long in a walrus, but the human male has lost it completely. According to a new report published in Proceedings of the Royal Society, the lack of a penis bone in human males may be a consequence of monogamy and quick sex. The Guardian reports: Known as the baculum to scientists with an interest, the penis bone is a marvel of evolution. It pops up in mammals and primates around the world, but varies so much in terms of length and whether it is present at all, that it is described as the most diverse bone ever to exist. Prompted by the extraordinary differences in penis bone length found in the animal kingdom, scientists set out to reconstruct the evolutionary story of the baculum, by tracing its appearance in mammals and primates throughout history. They found that the penis bone evolved in mammals more than 95 million years ago and was present in the first primates that emerged about 50 million years ago. From that moment on, the baculum became larger in some animals and smaller in others. Kit Opie who ran the study with Matilda Brindle at University College London, said that penis bone length was longer in males that engaged in what he called "prolonged intromission." In plain English, that means that the act of penetration lasts for more than three minutes, a strategy that helps the male impregnate the female while keeping her away from competing males. The penis bone, which attaches at the tip of the penis rather than the base, provides structural support for male animals that engage in prolonged intromission. Humans may have lost their penis bones when monogamy emerged as the dominant reproductive strategy during the time of Homo erectus about 1.9 million years ago, the scientists believe. In monogamous relationships, the male does not need to spend a long time penetrating the female, because she is not likely to be leapt upon by other amorous males. That, at least, is the theory.

Comments

Monogamy not that old

[dargaud]

Their dates seem off. I thought that monogamy in humans had emerged with agriculture: once you own a plot of land and invested lots of work into it, you pretty much want to limit access to it (and its production), so that means only to your kids, and to be sure the kids are yours you pretty much have to be monogamous. See all the still existing tribes of hunter gatherers that practice polygamy.

Re:Credible study?

[TheRaven64]

The hypothesis doesn't really make sense. Chimpanzees do not practice monogamy, yet sex between chimps lasts a few seconds. In a pack or herd animal, the difference between spending a few seconds and spending a few minutes penetrating a female makes a negligible difference to that female's general availability: the male is still not going to be inside her for hours of the day. Oh, and chimpanzees do have a baculum, so the correlation is simply not there between longer intercourse and existence of a baculum.

Re:Not the only thing we've lost.

[serviscope_minor]

The immorality of cheating is not always...

That doesn't explain why you think divorce is bad.

Morality and monogamy are both in decline.

No, you have presented no evidence that morality is in decline. Frankly I'm not that convinced about monogamy either unless you're very clear about a decline relative to what.

As humans realize that marriage is more likely going to result in divorce,

That's kind of tautological. You are certainly less likely to get divorced if you don't marry.

I feel the concept of marriage itself will also become extinct.

As far as I'm concerned marriage is basically a mechanism to stop the surviving partner getting massively shafted when the other partner dies. It's also a way to formally build assets as a pair such that a split is fair.

In both cases it's basically there to give some legal protections to someone if something bad happens. Personally I'd be happy for the whole thing to go away and be replaced with civil partnerships across the board.

Celebrities start having kids well before marriage is brought into play

Lots of normal people do too.

and no one gives a shit anymore if they do.

Good! Why should anyone give a shit? If two people have completely separate careers and assets, the legal protections that marriage give don't really amount to all that much: you won't get boned if your partner dies.

That mentality will soon become infectious.

That mentality has already become infectious. And that's bad why, precisely?

Re:Credible study?

[pz]

you need to measure all mammals or a decent cross section.

Did you read the scientific article? They measured a large number of species, but limited their study to primates and carnivores, as it says in the title of the study:

Postcopulatory sexual selection influences baculum evolution in primates and carnivores

within the scientific article they give the details as to how many:

A supertree phylogeny of 5020 extant mammals was used to reconstruct the ancestral states of baculum presence across the mammalian order.

That sounds like a decent cross-section. Five thousand species.

Secondly, I am not sure how they came to their monogamy theory.

Did you read the scientific article? It's pretty well explained there. They correlated the mating strategy of each species with baculum length. The homo erectus link was done by the Guardian article reporter, though.

Primates in polygamous mating systems were found to have significantly longer bacula than those in other mating systems (n = 65, p = 0.032).

and later

Two more phylogenetic t-tests showed that primates in polygamous mating systems and seasonally breeding primates had significantly longer bacula than primates in other mating systems and those without a seasonal breeding pattern, highlighting the importance of postcopulatory sexual selection as a driver of bacular evolution.