Makes perfect sense to me. If you look at our culture now there is always that one male all the females in a group tend to go for.
Same for males there's always that 1 mega hotie you want to meet.
The only difference is even average females can have any guy they want while the same doesn't apply to guys.
The advent of agriculture gave females the ability to support their children more easily without the help of males and the more desirable males could have more offspring with so much food available.
Basically less females had to settle for second best to have offspring.
> Same for males there's always that 1 mega hotie you want to meet.
> The only difference is even average females can have any guy they want while the same doesn't apply to guys.
I'd rather say that the major difference is that while there is no (or very little) opportunity cost for a male that mates with the top woman and the next 100 women as well, there is a big opportunity cost for a female regardless of which male she chooses, so she is much more motivated to choose the top male.
Right. This is not a new theory. It's well known that evolution tends to favor polygamy where females are more selective and males are more promiscuous.
What's interesting is that this apparently started after agriculture rather than before. I had previously thought that maybe hunter gatherers practiced polygamy but it faded away as we become more agricultural.
Also 17 females to 1 male is pretty absurd. Even if you look at cultures that practiced polygamy in recent history it wasn't to that extent. And even when it was practiced, it wasn't necessarily common except in the very upper class, so the average female to male ratio would have been more reasonable.
We can only speculate to what degree this might have shaped our (recent) evolution. That's a huge selective pressure on males to have traits that would lead to them being the local king or whatever they were. And everyone alive today would be descended from those people.
>I had previously thought that maybe hunter gatherers practiced polygamy but it faded away as we become more agricultural.
I would have thought otherwise, there is very little incentive for you to labour for the tribe if you have no skin in the game, so to speak. So they would give you a wife otherwise, why fight for them? Why hunt? Why do anything to benefit anyone other than yourself? Since you have nothing to lose, you can even steal from them since no one you care about suffers.
> What's interesting is that this apparently started after agriculture rather than before.
Well, the effects become much more pronounced after agriculture.
> Also 17 females to 1 male is pretty absurd. Even if you look at cultures that practiced polygamy in recent history it wasn't to that extent.
17:1 ratio in females vs. males having descendant lines surviving to appear in modern DNA doesn't imply 17:1 female:male polygyny.
Heck, the reverse (women having multiple partners, especially a higher-station one with better prospects for having offspring and having them succeed in youth and a lower-station one with worse prospects later, perhaps after the previous one died) could contribute to this, though polygyny is probably part of the explanation.
Agriculture created surplus which meant that someone could feed a larger family.
If you are a hunter gatherer you need to be a very good one to support more than one wife, even if you are the chief.
With surplus generated by agriculture, spare time can be spent innovating to increase the surplus. Inequal skills in building a personal surplus - whether by conquest, investment or thrift - means that some people get richer. Richer men gain power and are able to not only attract more females but rewrite the rules to make it so.
A few generations of this and you change the population considerably.
Just started reading Harari's brief history of humankind and this gem perfectly fits in the rather unsettling story of our genetic pool. It is no longer the natural environment setting the conditions for who's fit to survive/chosen for reproduction but the present human culture which in turn is just the result of the previous.
If I had to choose an algorithm as an analogy, I'd say it is a recursion waiting for stack overflow. :)
What you're saying isn't wrong, but I doubt that societies where rulers have a monopoly on violence have existed long enough to have had an impact on evolution.
Under monogamy, women who previously would have become part of a powerful man's harem now reproduced with a man who previously would not have reproduced, therefore reducing the female/male reproduction ratio.
There are a number of factors (particularly in premodern societies) that produce the imbalance, but polygyny particularly exacerbates the imbalance (and, from a pre-existing state of polygyny, then, monogamy reduces it) because polygyny means that the most successful males are each able, in their reproductive prime, to secure, with social support, exclusive reproductive access to multiple of the most desirable females, which increases the expected ratio of females successfully reproducing in that generation to the number of males successfully reproducing.
(Because of the biology of reproduction, this would seem likely to be the case even if, in institutional terms, the practice of polygyny was balanced by equal practice of polyandry, but historically that wasn't the case anyway.)
I found the original article but sadly not freely available. This psmag.com article is thin and the graph of the data is so small I can't read much off of it. Google couldn't find any larger versions of the graph.
This is not my research area. However, I can't help but the results seem to radical to me. The dip in male diversity seems far too synchronized among so many different regions / cultures. Are there examples in recorded history of sudden reductions in male diversity that lasted for multiple generations?
> ~10% of the men who reside within the borders of the Mongol Empire as it was at the death of Genghis Khan may carry his Y chromosome, and so ~0.5% of men in the world, about 16 million individuals alive today, do so. Since 2003 there have been other cases of “super-Y” lineages. For example the Manchu lineage and the Uí Néill lineage. The existence of these Y chromosomal lineages, which have burst upon the genetic landscape like explosive stars sweeping aside all other variation before them, indicates a periodic it “winner-take-all” dynamic in human genetics more reminiscent of hyper-polygynous mammals such as elephant seals. As we do not exhibit the sexual dimorphism which is the norm in such organisms, it goes to show the plasticity of outcome due to the flexibility of human cultural forms.
This is a great passage from the Red Queen, that might explain what was happening at the time:
In the ancient empire of the Incas, sex was a heavily regulated industry. The sun-king Atahualpa kept fifteen hundred women in each of many “houses of virgins” throughout his kingdom. They were selected for their beauty and were rarely chosen after the age of eight—to ensure their virginity. But they did not all remain virgins for long: They were the emperor’s concubines. Beneath him, each rank of society afforded a harem of a particular legal size. Great lords had harems of more than seven hundred women. “Principal persons” were allowed fifty women; leaders of vassal nations, thirty; heads of provinces of 100,000 people, twenty; leaders of 1,000 people, fifteen; administrators of 500 people, twelve; governors of 100 people, eight; petty chiefs over 50 men, seven; chiefs of 10 men, five; chiefs of 5 men, three. That left precious few for the average male Indian whose enforced near-celibacy must have driven him to desperate acts, a fact attested to by the severity of the penalties that followed any cuckolding of his seniors. If a man violated one of Atahualpa’s women, he, his wife, his children, his relatives, his servants, his fellow villagers, and all his lamas would be put to death, the village would be destroyed, and the site strewn with stones. As a result, Atahualpa and his nobles had, shall we say, a majority holding in the paternity of the next generation. They systematically dispossessed less privileged men of their genetic share of posterity. Many of the Inca people were the children of powerful men. In the kingdom of Dahomey in West Africa, all women were at the pleasure of the king. Thousands of them were kept in the royal harem for his use, and the remainder he suffered to “marry” the more favored of his subjects. The result was that Dahomean kings were very fecund, while ordinary Dahomean men were often celibate and barren. In the city of Abomey, according to one nineteenth-century visitor, “it would be difficult to find Dahomeans who were not descended from royalty.” The connection between sex and power is a long one.
If wealth keeps getting concentrated in fewer and fewer hands, coupled with the sexual liberation of women, perhaps we'll see something like this again. 1% of the men enjoying 99% of procreation.
this theory doesn't make sense, because sexually liberated women are fucking/procreating with losers and deadbeats at just as high a rate or even higher than with wealthy guys. they are also divorcing their wealthy husbands and taking a boatload of cash for themselves.
in fact, a lot of seriously rich guys are sexually frustrated. modern society is not ancient incan feudalism, and it doesn't follow the same rules as 1950s western society either. it's unique.
Since a lot of early civilizations seemed to be very slave heavy I wonder if that had anything to do with it. Agriculture requires more labour which leads to more slaving. Male slaves would work the fields with less of a chance for reproduction, and the landowners/slaveowners would have their pick of the female slaves.
I've suspected as much would happen during the agricultural revolution, but I did not expect such a huge disparity.
If the 51% male/female ratio did not change, then 16 out of 17 males must have either been killed, enslaved, or been left frustrated. This would imply a highly patriarchal society where the local king and his cronies are the only ones fed, and to whom you would sell your daughters to. The only other explanation would be mass infanticide of males, but to see this in multiple regions is suspect.
"It wasn't like there was a mass death of males. They were there, so what were they doing?" The article raises a very good question. In all places studied, agriculture must have favored a highly stratified society.
One other hypothesis I can think of is the advent of barbarian warfare. Many parts of the old testament details how brutal life was, where various tribes are constantly at war and conquering other tribes.
Even several generations of warfare, where each village sacked involved killing the men and abducting the women, would filter out y-chromosomes to see such a large disparity.
This is the actual explanation. With one caveat... slavery.
Basically, agriculture allowed people to specialize. This included specializing in killing. (Soldiers). You would use these specialists to conquer other lands. Which, in turn, provided slave labor to increase production in agriculture and other sectors. So the conquered females would be used as "rewards" for the conquerors. And the conquered males would be used to increase production across the conquering society via slave labor.
So the explanation is pretty simple. In fact, the 17 to 1 figure is so low that I question whether they aren't missing something ??? Societies that developed later generally required enormous amounts of slave labor. That, coupled with the fact that there would have been an enormous amount of killing involved in taking the slaves in the first place, makes me wonder how the numbers turned out so evenhanded? I would have expected it to be an order of magnitude higher. But they did the study and have the data... so life must not have been quite as brutal as I thought it was.
I suppose it is possible that life was brutal... and less desirable females simply may not have been taken? This happened a lot in our own history. Slave auction records show that some female slaves in America sold for as much as 100 times the rate of a "regular" female slave. (And even more in some private trades we have records for). We can speculate on why that may have been... but I think it's safe to assume that in a less sophisticated time they may have simply dispensed with females and males who were in some way undesirable, or were not likely to survive the journey back.
Sparta maintained a 10:1 ratio of helots to Spartans, and that was in the early iron age. I imagine the ratio could have been substantially worse in the neolithic and bronze ages.
(Iron democratized violence compared to the bronze age, due to the lower cost of forging iron weapons. I'm sure neolithic violence had a different socioeconomic basis, but greater centralization of violence doesn't seem implausible.)
> Iron democratized violence compared to the bronze age
Could you expand on this? If I have the resources to make an iron sword and you don’t, I can cut your bronze spearhead like butter. That doesn’t seem particularly democratic.
During the Bronze Age, bronze weapons and armor were rarer. It cost more to mine and work bronze, and it cost more to buy a panoply. Therefore the distribution of those possessing the top-of-the-line violence capacity was concentrated in a narrow martial elite.
The Iron Age broadened the number of people who could afford a panoply, because iron was easier to mine and cheaper to work (once they figured out how). The distribution of those with the ability to use force was a substantially broader elite, less concentrated than during the Bronze Age.
When the ability to wield lethal violence becomes cheaper and available to a wider number of people, it's being "democratized." Samuel Colt's 1873 Single Action Army revolver is a more recent example of the democratization of violence capacity—“God made Men, but Samuel Colt made them all equal.” A similar argument can be made about the widespread availability of the cheap AK-47 following WWII.
> In fact, the 17 to 1 figure is so low that I question whether they aren't missing something ???
In a specific region at a specific time yes, I'm sure you can maintain a higher ratio, but the statistics we're talking about are global. We're presumably not talking about a single multi-continental mega-spartan society, but many regional societies that happened to be shaped by the same economic and cultural forces.
Within those societies they may have had very high slave ownership ratios, but there would always be some regions not under such strict control, or border areas between them where things get messy. For a start, if this stratification of society was based on agriculture, you'd only get it in regions that were agriculturaly productive.
Not necessarily. There are a lot of things that the article left out. Number 1 is that the Y chromosome is about 25% of the size of the X chromosomes and is also the fastest evolving portion of the human genome. Since this was a DNA based study, you have to control for this as well. I assume they have, but I don't know for certain. Additionally, aneuploidy (XXY, YYX, etc) may also account for some differences along with chimeric (2+ genomes per person due to fraternal twin merging in womb) anomalies. You also have to control for outliers such as Ghengis Khan and those types of mass rape and pillaging, as he has skewed the statistics a fair bit.
Still, if they controlled for all this, it is an AMAZING finding. That only 6% of males will reproduce is fantastical, especially within an agrarian society. I would love to know of other mammalian species that have such low reproductive rates compared to females.
True! Then it seems that the early agrarian humans had more of a herd mentality or reproductive structure of winner take all. Do other apes or monkeys have similar breeding structures? Fascinating stuff.
Gorillas form harem-like groups, but they're not as large, 3 to 6 females per male (often the groups have multiple related males). Chimps have dominant males, but females can and often do have sex with other males in the group. Bonobos are just ridiculously promiscous :)
I just found a book called "Human Natures: Genes, Cultures, and the Human Prospect" which claims that southern elephant seals have harems of 48 females on average O_O - that's probably the record among mammals.
None of the things you mention are large enough to account for more than a tiny fraction of this observation. There are only a handful of cases like Ghengis Khan and that Irish king who are ancestors to a fraction of a percent of the human population, which in any case don't exclude other men from ancestry. If you have ten children and I have one, I am still an ancestor, although your DNA will show up more frequently in future generations than mine.
These results suggest the actual exclusion of 95% of the male population from reproduction. Chromosomal disorders affect less than 1% of the population, which would be deep in the noise in this study.
With regard to the rate of evolution on the Y chromosome, I think it's pretty plausible that people who do this stuff for a living are aware of it and corrected for it. We don't know that for certain, but since we don't know anything with certainty--only with an overwhelmingly high degree of plausibility--that isn't a big criticism.
All of these seem possible, to some extant for humans. First, war kills males. A lot of war could potentially kill the majority of males.
Second, infanticide exists within the historical record. SO does slavery, castration, polygamy etc. It doesn't seem far fetched to imagine a highly polygamous society where the majority of men are denied partners by one or more of these.
War has rarely had a significant effect on populations, certainly nothing like the effect of disease. Although many men in the ancient world died by violence (as they do in pre-political societies and failed states today) killing with stone tools is pretty difficult and dangerous, so constant warfare that killed enough men to account for a 17:1 reproductive ratio for long enough to leave its mark today would have made agriculture almost impossible. So it isn't all that likely.
Social constraints on reproduction are considerably more likely. All human societies are mildly polygynous, with high-status males having more mates and low-status males having fewer. This is why human males are somewhat bigger than human females: bigger men were more successful in mate competition, despite the obvious disadvantage of a larger size for a tool-using opportunistic hunter-gatherer-scavenger [].
The remarkable thing about this finding is that the level of social control was high enough to sustain such an effective* exclusion of most men from mating opportunities. In every modern human society cheating ("extra-pair copulations") is a significant factor in reproductive statistics, and a 17:1 ratio suggests a system that was capable of actually excluding, not just nominally excluding, the vast majority of men from reproducing.
It's difficult to see how that could happen in a modern human population, but then again: men and women today are descendents of the 5% of males who were successful in reproducing under those circumstances, so it's not entirely implausible that we are considerably fiercer mate competitors than our pre-agrarian ancestors.
[*] Bigger, more muscular bodies require more fuel, so bigger men starve to death more frequently than smaller men during bad years, which all the data we have on pre-political peoples suggest were not infrequent.
> and a 17:1 ratio suggests a system that was capable of actually excluding, not just nominally excluding, the vast majority of men from reproducing.
It doesn't actually imply that, because many of them could have reproduced, but not had offspring that survived to reproduce for sufficient numbers of generations. Modern DNA won't distinguish that from didn't reproduce. So, the fact that the vast majority of men of the time weren't successful in reproducing in the long term (viewed by having descendants survive to the modern day) doesn't mean that they were effectively excluded from reproduction.
Thinking about limit-case scenarios, if the bottleneck lasted long enough, this could be a matter of 5% of the men having 1+epsilon male offspring and 95% having 1-epsilon male offspring. For even relatively modest values of epsilon that would give quite a large deviation in the population, given enough time.
The article suggests this went on for about 2000 years (8000-6000 BCE) which is 100 generations, so if epsilion was 0.05 then the favoured class would have fathered 99.5% of the male population at the end of that time (most of whom would have fallen into the unfavoured class over time, of course.) Because all women reproduced (more or less) I think they just fall out of the calculation.
So you are correct.
[Edit: the article actually suggests it was as much as 4000 years, so an even smaller disparity could work.]
> Bigger, more muscular bodies require more fuel, so bigger men starve to death more frequently than smaller men during bad years, which all the data we have on pre-political peoples suggest were not infrequent.
Take a group of ten males. Restrict their access to food such that eventually a few of them will die. What are some characteristics that the surviving males will share? One of them is not "they are physically weaker than the dead males".
I thought it had been observed with monkeys or apes that in times of scarcity they will share, but if you dump a whole truck load of bananas they will fight over them. The rise of agriculture would be a similar time of plenty which may be what triggered all the fighting and hoarding.
My 16 yr old is interested in pursuing this field (not sure what to call it - 'Genetic Anthropology'?). Can anyone recommend online resources to help a newbie get the lay of the land? Or in-person resources (talks, exhibits, clubs etc.) near Palo Alto CA ??
I would say if Carlos Bustamante or Stephen Montgomery are ever giving a talk to the public to check them out. They're both based out of Stanford Med, but their research touches on tracing Human demographic history. If she's still interested when applying for colleges, Harvard and The University of Chicago should both be on her list.
You should email Razib Khan at UC Davis. He's been blogging about this stuff for years. And just earlier today, the NYT announced that he's been brought on as one of their new opinion writers.
"In more recent history, as a global average, about four or five women reproduced for every one man"
Correct me if I'm wrong, but isn't this the same as saying one man, on average, will father a child with about four or five different women? I suppose given the timescale being discussed, "recent history" may mean the last few centuries, but this average still sounds very high to me.
You still get at least an element of this with pretty recent til-death-do-us-part versions of serial monogamy: Gauss, for instance, had two wives, marrying a friend of his first wife after she died, and had children with both of them.
(I'd be surprised if serial monogamy alone were enough to get a 4:1 ratio, but you can definitely get > 1:1 ratios out of it.)
4 or 5 might be high, but it's still noticeable anecdotally (although more rigorous analysis would be interesting).
My ex-wife and I have no children, but her current fiancee has children with his ex-wife (who has no other children), and she and him plan to have children together. My dad has children with his ex-wife (who has no children with other men) and current wife, but my mom (his current wife) has no children with her ex-husband.
So in a very small anecdotal sample, men who have children may often have children with 2 (or more, presumably) women over a lifetime, even though at any given time, monogamy prevails.
More like out of 5 men, on average only one would have any descendent whose genetic line survived until today. But he would have a lot.
Now, some of the other 4 might have had children, but they might have dies young, or in turn not have had any descendants whose genetic line is still around.
Of course, the same would have happened to women, so maybe out of 15 men and 15 women, 5 women and 1 man have genes that are still around.
Also note that, unless I misunderstand, this only applies to single gendered lineage. That is there must be an unbroken chain of male ancestors for the male genes, and female ancestors for the female genes. If one of the men without surviving male genes had 3 daughters who went on to have lots of kids, his genes wouldn't be seen in this data, even though his other genes are with us.
Having gone through that line of thought, I wonder if we're looking at some kind of "compound interest" effect here. I mean, if the male-only gene has 10% less chance to survive a generation, does it add up to much bigger and bigger numbers after hundreds of generations?
Not particularly surprising. In the ancient world, men were often killed in various ways (conflict, hunting accidents) or enslaved so the gender ratio was quite skewed.
I mean, typical ancient warfare meant you attack a town, kill/enslave all the men and boys, rape all the women, and ensure your culture's dominance over them for the next generation or two...
I have a hunch that this ancient way of warfare is still the optimal way to destroy a culture and achieve total victory. Not that it's acceptable in any way, but imagine if the US had done this in Iraq and Afghanistan. It is heart-wrenching to think about, but I think it would have worked.
Only against non-muslims, as far as I've gathered. Most of the muslim world (as far as I've gathered) isn't particularly religious, just very socially conservative. So IS isn't employing this tactic to its full advantage here. Nor is it clear how they could, because as long as you go through all the motions it's hard to check whether you really have all that much religious fervour.
And don't forget the death of women during childbirth. That would leave a father/child pair - I'm sure the fathers in that instance would not be voluntarily celibate afterwards.
Eunuch's and harems. The rich and powerful males kept all their local women in a harem and forced all the other competing males to become eunuchs. Not fun, but it fits with the Monty Python version of history.... ;)
First: The fight _is_ against the top. 'The top', more precisely the structure that enables 'the top', is the patriarchy that feminist have always been fighting against.
Second: Even thinking of it as 'the top', 'the few that get to have all the pro-creation' as another commenter wrote is bad. Because the 1700 concubines, they weren't treated fairly. They taken away from their parents at age 8, held captive for sex and raped if they didn't comply.
Feminists are fighting for the women first. But the structure that enables this hurts everybody.
Sounds to me like slavery. The women slaves had babies, the male slaves were workers and soldiers.
In a way, it sort of sounds like a eusocial sort of society, like a bee colony (but with the male female roles reversed). One reproducing male, many reproducing females, many non-reproducing males.
In populations studies at all scales, Adam is more recent than Eve. 10 years ago, I read it was Eve 120,000 years ago and Adam 60,000 years ago for the out of Africa theory.
- Claimants go to war with one another. Soldiers are invented, voluntary and noble at first. Religious later. Can't do mass conscription from the common man as he's working the essential farms.
- Losers happen made. Slavery is invented.
- Slaves work the mines and other harsh labor, allow for post-agrarian activities and advanced economies.
- King sits back and lets the the whole clusterfuck evolve in his favor.
- Claimants go to war with one another. Soldiers are invented, voluntary and noble at first. Religious later. Can't do mass conscription from the common man as he's working the essential farms.
- Losers happen. Slavery is invented.
- Slaves work the mines and other harsh labor, which allows for post-agrarian activities and advanced economies.
- King sits back and lets the the whole clusterfuck evolve in his favor.
A auto-catalytic male shortage. Easy peasy.
Inadvertently, I have just Twitterized the Old Testament.
> Another member of the research team, a biological anthropologist, hypothesizes that somehow, only a few men accumulated lots of wealth and power, leaving nothing for others.
This line cracked me up.
Yes, "somehow" indeed. Quite a mystery we have on our hands here!
92 comments
[ 3.6 ms ] story [ 121 ms ] threadSame for males there's always that 1 mega hotie you want to meet.
The only difference is even average females can have any guy they want while the same doesn't apply to guys.
The advent of agriculture gave females the ability to support their children more easily without the help of males and the more desirable males could have more offspring with so much food available.
Basically less females had to settle for second best to have offspring.
I'd rather say that the major difference is that while there is no (or very little) opportunity cost for a male that mates with the top woman and the next 100 women as well, there is a big opportunity cost for a female regardless of which male she chooses, so she is much more motivated to choose the top male.
What's interesting is that this apparently started after agriculture rather than before. I had previously thought that maybe hunter gatherers practiced polygamy but it faded away as we become more agricultural.
Also 17 females to 1 male is pretty absurd. Even if you look at cultures that practiced polygamy in recent history it wasn't to that extent. And even when it was practiced, it wasn't necessarily common except in the very upper class, so the average female to male ratio would have been more reasonable.
We can only speculate to what degree this might have shaped our (recent) evolution. That's a huge selective pressure on males to have traits that would lead to them being the local king or whatever they were. And everyone alive today would be descended from those people.
I would have thought otherwise, there is very little incentive for you to labour for the tribe if you have no skin in the game, so to speak. So they would give you a wife otherwise, why fight for them? Why hunt? Why do anything to benefit anyone other than yourself? Since you have nothing to lose, you can even steal from them since no one you care about suffers.
Or lead them to "steal" secret reproductions? There's only "one" king, but there could be more than 1 "illegitimate" fathers.
Well, the effects become much more pronounced after agriculture.
> Also 17 females to 1 male is pretty absurd. Even if you look at cultures that practiced polygamy in recent history it wasn't to that extent.
17:1 ratio in females vs. males having descendant lines surviving to appear in modern DNA doesn't imply 17:1 female:male polygyny.
Heck, the reverse (women having multiple partners, especially a higher-station one with better prospects for having offspring and having them succeed in youth and a lower-station one with worse prospects later, perhaps after the previous one died) could contribute to this, though polygyny is probably part of the explanation.
If you are a hunter gatherer you need to be a very good one to support more than one wife, even if you are the chief.
With surplus generated by agriculture, spare time can be spent innovating to increase the surplus. Inequal skills in building a personal surplus - whether by conquest, investment or thrift - means that some people get richer. Richer men gain power and are able to not only attract more females but rewrite the rules to make it so.
A few generations of this and you change the population considerably.
If I had to choose an algorithm as an analogy, I'd say it is a recursion waiting for stack overflow. :)
(Because of the biology of reproduction, this would seem likely to be the case even if, in institutional terms, the practice of polygyny was balanced by equal practice of polyandry, but historically that wasn't the case anyway.)
Does anyone know a better source?
I found the original article but sadly not freely available. This psmag.com article is thin and the graph of the data is so small I can't read much off of it. Google couldn't find any larger versions of the graph.
> ~10% of the men who reside within the borders of the Mongol Empire as it was at the death of Genghis Khan may carry his Y chromosome, and so ~0.5% of men in the world, about 16 million individuals alive today, do so. Since 2003 there have been other cases of “super-Y” lineages. For example the Manchu lineage and the Uí Néill lineage. The existence of these Y chromosomal lineages, which have burst upon the genetic landscape like explosive stars sweeping aside all other variation before them, indicates a periodic it “winner-take-all” dynamic in human genetics more reminiscent of hyper-polygynous mammals such as elephant seals. As we do not exhibit the sexual dimorphism which is the norm in such organisms, it goes to show the plasticity of outcome due to the flexibility of human cultural forms.
http://amazon.com/Red-Queen-Evolution-Human-Nature/dp/006055...
In the ancient empire of the Incas, sex was a heavily regulated industry. The sun-king Atahualpa kept fifteen hundred women in each of many “houses of virgins” throughout his kingdom. They were selected for their beauty and were rarely chosen after the age of eight—to ensure their virginity. But they did not all remain virgins for long: They were the emperor’s concubines. Beneath him, each rank of society afforded a harem of a particular legal size. Great lords had harems of more than seven hundred women. “Principal persons” were allowed fifty women; leaders of vassal nations, thirty; heads of provinces of 100,000 people, twenty; leaders of 1,000 people, fifteen; administrators of 500 people, twelve; governors of 100 people, eight; petty chiefs over 50 men, seven; chiefs of 10 men, five; chiefs of 5 men, three. That left precious few for the average male Indian whose enforced near-celibacy must have driven him to desperate acts, a fact attested to by the severity of the penalties that followed any cuckolding of his seniors. If a man violated one of Atahualpa’s women, he, his wife, his children, his relatives, his servants, his fellow villagers, and all his lamas would be put to death, the village would be destroyed, and the site strewn with stones. As a result, Atahualpa and his nobles had, shall we say, a majority holding in the paternity of the next generation. They systematically dispossessed less privileged men of their genetic share of posterity. Many of the Inca people were the children of powerful men. In the kingdom of Dahomey in West Africa, all women were at the pleasure of the king. Thousands of them were kept in the royal harem for his use, and the remainder he suffered to “marry” the more favored of his subjects. The result was that Dahomean kings were very fecund, while ordinary Dahomean men were often celibate and barren. In the city of Abomey, according to one nineteenth-century visitor, “it would be difficult to find Dahomeans who were not descended from royalty.” The connection between sex and power is a long one.
in fact, a lot of seriously rich guys are sexually frustrated. modern society is not ancient incan feudalism, and it doesn't follow the same rules as 1950s western society either. it's unique.
If the 51% male/female ratio did not change, then 16 out of 17 males must have either been killed, enslaved, or been left frustrated. This would imply a highly patriarchal society where the local king and his cronies are the only ones fed, and to whom you would sell your daughters to. The only other explanation would be mass infanticide of males, but to see this in multiple regions is suspect.
"It wasn't like there was a mass death of males. They were there, so what were they doing?" The article raises a very good question. In all places studied, agriculture must have favored a highly stratified society.
Even several generations of warfare, where each village sacked involved killing the men and abducting the women, would filter out y-chromosomes to see such a large disparity.
Basically, agriculture allowed people to specialize. This included specializing in killing. (Soldiers). You would use these specialists to conquer other lands. Which, in turn, provided slave labor to increase production in agriculture and other sectors. So the conquered females would be used as "rewards" for the conquerors. And the conquered males would be used to increase production across the conquering society via slave labor.
So the explanation is pretty simple. In fact, the 17 to 1 figure is so low that I question whether they aren't missing something ??? Societies that developed later generally required enormous amounts of slave labor. That, coupled with the fact that there would have been an enormous amount of killing involved in taking the slaves in the first place, makes me wonder how the numbers turned out so evenhanded? I would have expected it to be an order of magnitude higher. But they did the study and have the data... so life must not have been quite as brutal as I thought it was.
I suppose it is possible that life was brutal... and less desirable females simply may not have been taken? This happened a lot in our own history. Slave auction records show that some female slaves in America sold for as much as 100 times the rate of a "regular" female slave. (And even more in some private trades we have records for). We can speculate on why that may have been... but I think it's safe to assume that in a less sophisticated time they may have simply dispensed with females and males who were in some way undesirable, or were not likely to survive the journey back.
(Iron democratized violence compared to the bronze age, due to the lower cost of forging iron weapons. I'm sure neolithic violence had a different socioeconomic basis, but greater centralization of violence doesn't seem implausible.)
Could you expand on this? If I have the resources to make an iron sword and you don’t, I can cut your bronze spearhead like butter. That doesn’t seem particularly democratic.
The Iron Age broadened the number of people who could afford a panoply, because iron was easier to mine and cheaper to work (once they figured out how). The distribution of those with the ability to use force was a substantially broader elite, less concentrated than during the Bronze Age.
When the ability to wield lethal violence becomes cheaper and available to a wider number of people, it's being "democratized." Samuel Colt's 1873 Single Action Army revolver is a more recent example of the democratization of violence capacity—“God made Men, but Samuel Colt made them all equal.” A similar argument can be made about the widespread availability of the cheap AK-47 following WWII.
Bronze isn't particularly worse than iron, when it comes to making weapons. Its primary drawback is its scarcity, compared to iron.
In a specific region at a specific time yes, I'm sure you can maintain a higher ratio, but the statistics we're talking about are global. We're presumably not talking about a single multi-continental mega-spartan society, but many regional societies that happened to be shaped by the same economic and cultural forces.
Within those societies they may have had very high slave ownership ratios, but there would always be some regions not under such strict control, or border areas between them where things get messy. For a start, if this stratification of society was based on agriculture, you'd only get it in regions that were agriculturaly productive.
Still, if they controlled for all this, it is an AMAZING finding. That only 6% of males will reproduce is fantastical, especially within an agrarian society. I would love to know of other mammalian species that have such low reproductive rates compared to females.
https://en.wikipedia.org/wiki/Y_chromosome
Some species of deer probably match it.
I just found a book called "Human Natures: Genes, Cultures, and the Human Prospect" which claims that southern elephant seals have harems of 48 females on average O_O - that's probably the record among mammals.
These results suggest the actual exclusion of 95% of the male population from reproduction. Chromosomal disorders affect less than 1% of the population, which would be deep in the noise in this study.
With regard to the rate of evolution on the Y chromosome, I think it's pretty plausible that people who do this stuff for a living are aware of it and corrected for it. We don't know that for certain, but since we don't know anything with certainty--only with an overwhelmingly high degree of plausibility--that isn't a big criticism.
Edit: also, any harem-keeping species is likely to have a high proportion of genetic losers amongst the males: https://en.wikipedia.org/wiki/Harem_%28zoology%29#Mammals
Second, infanticide exists within the historical record. SO does slavery, castration, polygamy etc. It doesn't seem far fetched to imagine a highly polygamous society where the majority of men are denied partners by one or more of these.
Social constraints on reproduction are considerably more likely. All human societies are mildly polygynous, with high-status males having more mates and low-status males having fewer. This is why human males are somewhat bigger than human females: bigger men were more successful in mate competition, despite the obvious disadvantage of a larger size for a tool-using opportunistic hunter-gatherer-scavenger [].
The remarkable thing about this finding is that the level of social control was high enough to sustain such an effective* exclusion of most men from mating opportunities. In every modern human society cheating ("extra-pair copulations") is a significant factor in reproductive statistics, and a 17:1 ratio suggests a system that was capable of actually excluding, not just nominally excluding, the vast majority of men from reproducing.
It's difficult to see how that could happen in a modern human population, but then again: men and women today are descendents of the 5% of males who were successful in reproducing under those circumstances, so it's not entirely implausible that we are considerably fiercer mate competitors than our pre-agrarian ancestors.
[*] Bigger, more muscular bodies require more fuel, so bigger men starve to death more frequently than smaller men during bad years, which all the data we have on pre-political peoples suggest were not infrequent.
It doesn't actually imply that, because many of them could have reproduced, but not had offspring that survived to reproduce for sufficient numbers of generations. Modern DNA won't distinguish that from didn't reproduce. So, the fact that the vast majority of men of the time weren't successful in reproducing in the long term (viewed by having descendants survive to the modern day) doesn't mean that they were effectively excluded from reproduction.
Thinking about limit-case scenarios, if the bottleneck lasted long enough, this could be a matter of 5% of the men having 1+epsilon male offspring and 95% having 1-epsilon male offspring. For even relatively modest values of epsilon that would give quite a large deviation in the population, given enough time.
The article suggests this went on for about 2000 years (8000-6000 BCE) which is 100 generations, so if epsilion was 0.05 then the favoured class would have fathered 99.5% of the male population at the end of that time (most of whom would have fallen into the unfavoured class over time, of course.) Because all women reproduced (more or less) I think they just fall out of the calculation.
So you are correct.
[Edit: the article actually suggests it was as much as 4000 years, so an even smaller disparity could work.]
Take a group of ten males. Restrict their access to food such that eventually a few of them will die. What are some characteristics that the surviving males will share? One of them is not "they are physically weaker than the dead males".
1: http://genome.cshlp.org/content/suppl/2015/02/18/gr.186684.1...
Yeah, thank god we're past this as a species
Correct me if I'm wrong, but isn't this the same as saying one man, on average, will father a child with about four or five different women? I suppose given the timescale being discussed, "recent history" may mean the last few centuries, but this average still sounds very high to me.
(I'd be surprised if serial monogamy alone were enough to get a 4:1 ratio, but you can definitely get > 1:1 ratios out of it.)
My ex-wife and I have no children, but her current fiancee has children with his ex-wife (who has no other children), and she and him plan to have children together. My dad has children with his ex-wife (who has no children with other men) and current wife, but my mom (his current wife) has no children with her ex-husband.
So in a very small anecdotal sample, men who have children may often have children with 2 (or more, presumably) women over a lifetime, even though at any given time, monogamy prevails.
I don't know if this statistic is actually limited by "recent history" or not.
More like out of 5 men, on average only one would have any descendent whose genetic line survived until today. But he would have a lot.
Now, some of the other 4 might have had children, but they might have dies young, or in turn not have had any descendants whose genetic line is still around.
Of course, the same would have happened to women, so maybe out of 15 men and 15 women, 5 women and 1 man have genes that are still around.
Also note that, unless I misunderstand, this only applies to single gendered lineage. That is there must be an unbroken chain of male ancestors for the male genes, and female ancestors for the female genes. If one of the men without surviving male genes had 3 daughters who went on to have lots of kids, his genes wouldn't be seen in this data, even though his other genes are with us.
Having gone through that line of thought, I wonder if we're looking at some kind of "compound interest" effect here. I mean, if the male-only gene has 10% less chance to survive a generation, does it add up to much bigger and bigger numbers after hundreds of generations?
I'm not sure if that clarified much...
I mean, typical ancient warfare meant you attack a town, kill/enslave all the men and boys, rape all the women, and ensure your culture's dominance over them for the next generation or two...
"estimates of the numbers of German women raped by Soviet soldiers have ranged up to 2 million"
Feminists, take note: men are not privileged. Just those who were privileged were men. The fight must be against the few at the top.
Second: Even thinking of it as 'the top', 'the few that get to have all the pro-creation' as another commenter wrote is bad. Because the 1700 concubines, they weren't treated fairly. They taken away from their parents at age 8, held captive for sex and raped if they didn't comply.
Feminists are fighting for the women first. But the structure that enables this hurts everybody.
In a way, it sort of sounds like a eusocial sort of society, like a bee colony (but with the male female roles reversed). One reproducing male, many reproducing females, many non-reproducing males.
- No contraception. Much baby.
- Many claims to throne in 18 years.
- Claimants go to war with one another. Soldiers are invented, voluntary and noble at first. Religious later. Can't do mass conscription from the common man as he's working the essential farms.
- Losers happen made. Slavery is invented.
- Slaves work the mines and other harsh labor, allow for post-agrarian activities and advanced economies.
- King sits back and lets the the whole clusterfuck evolve in his favor.
A self-regulating male shortage. Easy peasy.
- No contraception. Much baby.
- Many claims to throne in 14-18 years.
- Claimants go to war with one another. Soldiers are invented, voluntary and noble at first. Religious later. Can't do mass conscription from the common man as he's working the essential farms.
- Losers happen. Slavery is invented.
- Slaves work the mines and other harsh labor, which allows for post-agrarian activities and advanced economies.
- King sits back and lets the the whole clusterfuck evolve in his favor.
A auto-catalytic male shortage. Easy peasy.
Inadvertently, I have just Twitterized the Old Testament.
This line cracked me up.
Yes, "somehow" indeed. Quite a mystery we have on our hands here!