[ExI] Strange mystery explained

[Stuart LaForge]

Keith Henson wrote:

> However, to cut to the chase, it looks like patrilineal early farming
> groups were killing off each other's males.  This considerably diminished
> the variations of Y chromosomes since when one group got the upper hand,
> it was common for the winners to kill the losers to the last man (and boy)
> and take the young women as booty.  It seems this process started when the
> Neolithic agricultural revolution began
> and ended when violence between patrilineal clans was suppressed by
> Chieftains or a State.
> https://www.nature.com/articles/s41467-018-04375-6#article-comments

The author's hypothesis convincingly tells us "what" happened but doesn't
tell us "how" it happened. The winners killing the losers to last man is
not sufficient to explain the bottle neck, because it does not explain why
the winners were consistently the winners in each and every confrontation.

Lions in the wild, for example, operate like this normally where young
wandering males challenge older established males for territory and the
prides of females that come along with that territory. Should the
challenger win, he kills all the cubs of the previous lion. Despite this
consistent infanticide, approximately 1 in 5 male lions still manages to
survive and reproduce, so you don't see a genetic bottleneck of limited
diversity such as the 1 in 17 figure quoted in the paper. This is because
the contests between lions is fair: teeth, claws, and manes all around
with speed, strength, and cunning being the deciding factors.

In order for the same patrilineal clans to have won those wars every time,
they would have had to have had a considerable technological advantage
over their competitors. Whilst agriculture, and the large amounts of land
it requires, would have given motivation for such wars, I don't see it
giving early farmers a tactical advantage over hunter-gatherers. Instead,
the technological advantage could have been metal weaponry that was
concomitantly developed along with farming tools such as scythes.

It turns out that the time period during which the bottleneck occurred
which is stated to be about 7000 BP to 5000 BP, in the article,
corresponds to about 5000 BC to 3000 BC. This pretty closely coincides
with the Chalcolithic period or the Copper Age which was a transition
period between the Stone Age and the Bronze Age which followed it.

The oldest confidently dated archaeological evidence of copper smelting
comes from the Belovode site on Rudnick Mountain in Serbia. It is dated to
5000 BC which is about same time the bottleneck and presumably the culling
of males began. The availability of copper would have allowed those with
the knowledge of smelting to fashion "Otzi the Iceman" style copper axes.

https://i.ytimg.com/vi/ZmmU7hLPq7w/hqdefault.jpg
https://www.youtube.com/watch?v=ZmmU7hLPq7w

While one can clearly see the advantage a copper axe would have had over
the handaxe shown, one has to wonder if the copper axe shown would be all
that advantageous over the hafted stone axe shown. Especially considering
bows with stone tipped arrows were extant and still quite deadly as
evidenced by Otzi's own fate.

Then again, perhaps the availability of copper tools allowed the
fashioning of true armor for the first time in history? Something like
this:

http://www.ancient-origins.net/news-history-archaeology/archaeologists-unearth-4000-year-old-siberian-knight-armour-102090

Regardless, it is an interesting question.

Stuart LaForge