The story goes that a spinster inherited a farm and she wanted to raise chickens and sell the eggs. So she put in an order for thirty chickens and thirty roosters to the local broker. “Ma’am,” the dealer told her. You really only need one rooster for that many chickens.”
“Well!” said the woman in a huff. “Isn’t that just the way a man would think!”
Strictly speaking, polygamy is divided into two categories, polygyny and polyandry, the former being one male with multiple mates and the other being one female with multiple mates. In practice, polygyny is so seldom used as a label that it doesn’t even show up in my spell checker, and polygamy is generally taken to mean the multiple wives thing.
The predominance of polygyny over polyandry is pretty typical of mammals where there is substantial sexual dimorphism, i.e. where males are larger than females. In species where it’s the other way around (large females and small males), things aren’t quite so phalocentric, with the extreme cases being those insectoid suicide matings (bees, black widow spiders, etc.), that have served as the basis of many horror stories (or, contrariwise, female revenge fantasies, point-of-view being a factor in nomenclature).
Sociobiology and ethnology offer a lot of speculative theories on the nature of polygamy, most of them controversial, (well duh). It’s pretty easy to see how a shortage of males can lead to polygyny. Indeed, one hard fact in population demographics is that the birth rate in any given region depends on the number of women of child bearing age—period. It’s almost impossible to reduce the number of men to a level where it affects the number of children being born.
In the state of perpetual warfare that sometimes exists in some societies, a shortage of men is almost inevitable, and some sort of polygyny often results. Given long enough, this becomes institutionalized. It’s not necessary to invoke perpetual warfare, either; hunting large game is dangerous, and hunter/gatherer societies can easily develop male shortages and the whole “alpha male” structure, almost by accident.
A suggested countervailing influence in stone age societies is female infanticide. This is the dark underbelly of Eden, the crude population control measure that allowed the human population to remain stable for millennia. Some anthropologists have suggested that this sometimes led to polyandry, due to a shortage of females. It’s interesting to speculate about the future outcome of the gender imbalances that are being set up in some Asian countries as a result of pre-natal screening and selective abortion.
Female infanticide as a population control measure has been suggested as the origin of the form of institutionalized polyandry that exists in Tibet. One difficulty with this argument is that the custom is confined to a property owning class (which suggests that privation isn’t the primary origin), and that the woman’s spouses are fraternal, i.e. she marries the “family” as it were, and one brother is dominant, with the rest merely enjoying spousal privileges. That suggests that in this case, the custom is more akin to primogeniture, with the multiple husbands simply as insurance against infertility in the primary “alpha” male. It may be noted that this looks similar to the commonly noted phenomenon of infidelity on the part of the mates of the alpha males in various primate societies.
Substantial gender imbalances were the norm in the expansion of Europeans into the Americas, and history and folklore abounds in unconventional modes of co-habitation in the Old West. The Mormons dealt with their substantial gender imbalance in the early church with a “revelation” of God’s blessing for polygyny. By contrast, Wyoming Territory, responded to an extreme shortage of women by giving them voting rights in 1869, as an attempt to get more women to move to the territory.
A careful examination of social behavior in the Old West suggests that there is a form of polyandry that is seldom noted as such: prostitution. The legal system does its best to deny that the prostitute/client relationship is legitimate, as do practically all religious doctrines. But on any honest analysis suggests otherwise. What does a polyandrous relationship have that does not appear in prostitution? Certainly emotional relationships form; the client who wants to “make an honest woman of her” is so common as to be a stereotype. Children? Frequently children are the reason why women turn to prostitution. While it’s true that the anonymous sex of a street hooker doesn’t much look like marriage, it’s easy to find more domesticated arrangements upscale in the sex trade, while contrariwise, it’s not that difficult to find legal marriages that make a street hooker and her john look positively loving and healthy.
There’s no doubt that human relationships rapidly increase in complexity as the number of players increases. Same-sex monogamy will inevitably be even less complicated than the sort of opposite sex serial monogamy that has become normal in the modern world. By the same token, divorces in same sex marriages will certainly be at least as complicated as opposite sex divorces. Having both spouses “cheat” with the same individual is relatively uncommon in opposite sex couples, though it does happen, and, yes that’s yet another kind of gossip that will probably never appear in these essays.
But group arrangements, even when the group is so small as three, becomes so very complicated so very quickly that I doubt that they will ever be common enough for the law and mores to take much note of them. It should go without saying that such “outlaw” behavior is just the sort of thing that young people do as a way of testing limits, their own and others, just another set of behaviors that Seem Like a Good Idea At the Time.