What do Tiger Woods, Charlie Sheen, and Moulay Ismail have in common?

(Charlie, Tiger, and Moulay would have a lot to discuss if they ever got together, and it wouldn't be about golf.)

The answer to the question in the title is SEX.   More specifically, they all have had sex with many different women during their lives.

We do not know the exact number, but it is probably safe to conclude from all reports that Tiger Woods and Charlie Sheen have had sex with dozens of women, both of whom still have a looooong way to go before they're finished with their sexual lives.  Certainly the number of sexual consorts they have had is greater than the number reached by most, or all, of you reading this essay.  But, in fact, that is exactly what a behavioral ecologist expects.

A couple of weeks ago I wrote an essay here posing why people become avid fans of sports teams.  My hypothesis was that those individuals who followed and proclaimed their allegiance to a football or baseball team were enhancing their status, at least a little.  And I recognized that this phenomenon of being a fan is more common in males than in females.  I should have written this essay first, and then that one, because that would seem to be the more logical order in which to present these ideas.  But I'm old, and this is my blog, and I can do anything I want here.

The idea here is that men seek as high a status as they can muster, and with that status, comes access to women.  And this has been going on for millions of years--in Homo sapiens, and in all the ancestral species before that.  Realize that men all over the world are seeking high status by trying to excel at whatever they do in life (e.g., whether being a surgeon, a golfer, an actor, a warrior in the Amazon, a politician, or an assembly line worker), because the payoff for millennia has been to leave more offspring than those who don't.  And, as we learned in that out-of-order blog of mine, men don't have to be conscious of all this evolutionary stuff; they do it because it feels good.

Of course, this would all work only if there is a correlation between the number of women with whom a man has sexual intercourse and the number of children he sires during his life.  But, you are saying, women can have all the sex they want and not get pregnant, because of their use of contraception.  But that is a relatively new development in the evolution of humans.  I have never thought that men seek women to have more children, but they seek out women because sex feels good.  It is the proximate goal to have sex that drives this system in the short term, not the ultimate outcome of leaving genes in more offspring.  Over our long history, however, more sex must have equated to having more children, on average.

By the way, one of my favorite activities is to google famous people, and then to read the Wikipedia account of their lives.  Usually those accounts contain a "Personal" section, which details the number of times the person has been married, the number of children they had with each wife, and maybe the number of non-wife lovers they had during their illustrious life.  Think of a few famous men you know, and do this little exercise.  I think you will then agree that they seem to have had a lot more "encounters" with females than you have, or than most of the men you know.  And those numbers reported there are just the official tally.

But how successful reproductively can one man be?  Let's introduce Moulay Ismaïl Ibn Sharif (the "Warrior King"), who ruled Morocco from 1672-1727.  Moulay ruled for a decade longer than even Qaddafi has ruled Libya.  Moulay Ismail was a particularly ruthless and bloodthirsty ruler, who used to kill his servants on a whim.  It is said that he once slit the throats of two servants just to try out a new blade he had been given.  But the Alaouite sultan's claim to fame for our purposes was that he is thought to have sired more than 1,000 children, the most in recorded history.  By 1703, he had 525 sons and 342 daughters; less than two decades later, he tallied his 700th son.  One biologist calculated that to produce this number of children from the vast harem of wives he amassed, Moulay would have had to copulate, on average, with 1.2 women every day over the course of 60 years.  Tiger and Charlie have some catching up to do if they want to capture that record.

Should we condemn these self-serving, sex-seeking males of our species for their dastardly way of life?  If we are going to assign some blame for this behavior, we need to look further than the males themselves.  Females share in the blame, for if they had not been attracted to high-status men for eons, this system would have broken down long ago.  Remember that for men, quantity is everything in sex, while for females, quality is paramount.

In addition, all this striving to be the best you can be has probably resulted in most of the accomplishments in art, music, architecture, medicine, sports, and science attributed to men.  Think for a moment how different history would have been if this biological relationship between status and reproductive success had been different from what it is.  That is one heck of an interesting mental exercise. If that doesn't give you something to think about when your electricity is out, go back to playing Scrabble by candlelight.


Article first published as What Do Tiger Woods, Charlie Sheen and Moulay Ismail Have in Common? on Technorati.

The dispersal of human offspring

(Human offspring disperse for the same reasons as these dandelion seeds, but the effects of dispersal are quite different.)

It is normal in birds and mammals for young to disperse from their birth area.  There are a variety of biological explanations as to why this is adaptive.  A common reason given is that dispersal reduces the chances of offspring mating with their parents (or competing with them for resources like food), which would result in a higher degree of inbreeding and a higher probability of recessive, deleterious genes manifesting themselves in the offspring of such a mating between close relatives.  In birds, females tend to disperse farther than males from their natal area, and in mammals, males tend to disperse farther than females.  Again, if male and female siblings disperse different distances from where they were born, they are less likely to encounter each other when they reach reproductive age and, therefore, siblings are less likely to mate with each other.  So, while birds and mammals have different sex-specific dispersal patterns, the effect is the same.

We are all familiar with the bad jokes told about human inbreeding (=incest) in communities where everyone stays near home, and there is little movement of new humans into this isolated community.  This is probably an extreme case for humans.  I have to figure that for most of human history (3-4 million years), young males probably dispersed to nearby villages, probably no more than miles or tens of miles away.  After all, they had to walk.  Once they got there and were accepted, they found young females to mate, settled down in their new digs, and had babies.  Young female humans probably stayed near home more often, although the details of all this varied with cultures around the world.  In some cultures, females are simply kidnapped from nearby villages and brought to the male's home.  Important as well is that in this ancestral system everyone knew everyone else within the home community, and they probably knew almost everyone in all the neighboring communities. 

But in recent times, meaning decades or a few centuries, this pattern of relatively short dispersal distance and everyone knowing everyone else changed dramatically.  Many young people still remain in close proximity to their parents and to where they were born; they retain close friendships with many of their peers from high school.  But many others disperse hundreds or thousands of miles from their family, their birthplace, their homeland.  This can be a somewhat painful experience for those of us who enjoy being with our adult children on a regular basis.

This diaspora-like phenomenon has consequences for society as well, I believe.  Human behavior seems to be influenced and tempered mostly by peer pressure.  We tend to be on our best behavior when we are being watched by people who know us and who know our family.  Our family, in turn, puts pressure on us to behave in a socially-acceptable manner.  When humans move to a community where literally no one knows them, human behavior has a tendency to change.  I am not familiar with studies that document this, but I am betting they exist.  In other words, when you are not directly accountable to a social system in which your status is known and familiar to others, I predict that, on average, humans will be somewhat more likely to engage in immoral or illegal behavior.  For this pattern to emerge in the data, we would need to examine a sample of thousands of individuals who dispersed and compare their behavior to thousands of similar individuals who did not disperse.  If entire extended families dispersed together, I think my prediction would be weaker.

Thus, there are good biological reasons why human offspring might disperse from their natal area, but this dispersal may also have effects, or unintended consequences, in societies where it is common.  I love playing these mind games with myself to see where it leads me.  Having just helped one of my sons disperse even further away from home than he already was has caused me to focus on this topic again.  (In the case of my son's recent move, I am more concerned about what his new community will do to him than what he will do to it.  This must be a common parental reaction.)  I was always fascinated with dispersal in the mammals and birds I studied, but there is nothing quite like thinking about human behavior to get the juices flowing.  Of course, human dispersal is another one of those book-length issues, but maybe this little essay will start you thinking about the movement of people in a new and creative way.