Polygamy: how does the math work?

I’m not interested in a debate over the merits or demerits of polygamy. I just have a (very naive, I’m sure) question. If a man takes multiple wives, and the human race is roughly split 50/50 by sex, how does that work out? Won’t there necessarily be a lot of bachelors?

Yes, there are surplus men in such a situation. Read up on the Lost Boys.

I can’t get your link to open just now, but I Googled the text of your link (Lost Boys of Polygamy) and there’s a whole lot of baggage on the topic that didn’t interest me for this purpose. I’m just glad to know that I wasn’t missing something obvious. Thanks for the response. :slight_smile:

What tends to happen is older men marry younger women (or even teenage girls) and then father multiple children with them. A single man, if he waits long enough, will eventually be able to secure a bride even if she’s a generation (or two) younger than he. The community’s population keeps growing and the whole thing becomes a sort of pyramid scheme, with the inevitable crash. There will be a surplus of single men, but also of widowed women (typical if a 60 year-old man marring a 14 year-old girl becomes the norm), and if they pair up (a community that encourages polygamy might be inclined to discourage this for cultural/religious reasons) the surplus male population could be reduced.

Bachelors are expendable. That is how it works for many social mammals.

Not if there are an equal number of women acquiring multiple husbands in similar quantities.

True, but it sounds like he was assuming polygyny rather than true polygamy.

True women have seldom been forced to fight in wars and in many societies marriage/fatherhood lessed a man’s military liability.

There have also been societies where only the elite had multiple wives, and most of the population followed the standard one-to-a-customer system. If one man in a hundred has two wives, and one man in a thousand has five, that’s not going to have much impact on the society as a whole.

Isn’t that why we invented war?

No, it’s more how we invented war.


I doubt if there is a single example of a human culture in which this occurs. There are a few which permit polyandry, but even in those I don’t think it’s very common. Polygamy pretty much means polygyny in most human cultures.

I think this is the general case. In most polygamous societies, only the fairly well-to-do can afford to have more than one wife. And older men may be able to afford to take additional younger wives as their earning power increases with age.

Ah, but as Bryan Ekers points out, men often marry much younger women, who then become widows who frequently remarry. So just for example, you could have a society where men takes two wives on average, and women are married twice on average (serially, not simultaneously), and the math will work out just fine.

Didn’t the Discovery Channel kind of cover this to death in their documentary The Marrying Tribe? The culture they covered (Zoe Tribe?) permitted women to have multiple husbands and men to have multiple wives.

Do women have multiple husbands with the same frequency as men have multiple wives (which was the situation AHunter3 proposed)? The little I could find on Google indicates the practice is poorly understood. In any case, even if a few small tribes practice it, this social system is vanishingly rare compared to those cultures that practice polygyny (which outnumber those that practice monogamy, especially if one includes those that practice “informal” polygyny through having concubines or mistresses in addition to having an official wife).

Even if the math does work out, as per the OP there would still be an oversupply of bachelors, since a greater proportion of men would spend more of their lives unmarried than women. Women would generally marry young, while many men would have to wait until they were older to marry another man’s widow. If remarriage of widows were frequent, women would on average spend most of their lives married; many men would spend many years of adulthood as bachelors.

Now that the question is answered, I have a follow-up question, which may be more speculative. It seems to me that such a system would work very well for an expansionist empire: if the local girls are all married to the elite, then the local guys might have to look to conquered neighboring socieities to find mates, first killing off their male neighbors and then setting up shop (and expanding the empire’s borders) on their neighbor’s land.

Has this ever been the case? Have empires deliberately or inadvertantly set up something like this?


Just the other day, I watched one of my LDS comedy DVDs, done by some dude named Biscuit. His take on the polygamy:

Obviously, the math doesn’t work there either.

Don’t know, but the Incas had polygamy among the elite, with concubines also given for bravery in battle. http://www.dennisadamsseminars.com/machu-picchu/social.html

The conquered apparently provided new supplies of wives.

Caveat: The site I linked to is connected with, “…one of the most talked about spiritual and physical healers of our time…”: I suspect that his Peruvian learning is derived from secondary sources.

If you include mistresses and slaves in your accounting, that’s a pretty good description of the Roman Empire. Also the Spanish conquistadors.

Up until about the 19th Century, warfare usually consisted of wiping out your enemy’s adult males, and selling the women and children into slavery.

I just remembered a quotation from an old history textbook:

I suspect that “embrace” is probably not a literal translation.