Wednesday, February 5, 2020

Beakers, Monogamous as Wolves? (Sjogren et al, 2019)

We might imagine our distant ancestors as the heathens who lacked the decency to wash the dry blood and brains from their beards before dinner.  Foremost among them, the fierce Beaker who spread the M269 among his two dozen or so sobbing wives afterwards.  Does that characterization wholly square with the majority in their society?

Fierce as they were, the Beakers had their standards and apparently a sophisticated family system, as we learn in "Kinship and social organization in Copper Age Europe.  A cross-disciplinary analysis..." by Sjogren et al, 2019.  The study examines relationships in farm cemeteries at Irlbach and Alburg of Bavaria through personal DNA.

Cut from Fig 1.
It is becoming more evident that the Bell Beakers were a generally-monogamous folk.  This paper follows the Lech Valley paper and confirms the existence of a broader 'system' of female exogamy, patrilocality, patriarchy and fosterage.  The importance of this paper's implications cannot be underscored enough.

Sjogren et al. compare reconstructed PIE kinship structures to that of the Straubing Beakers, and a reasonable assessment is that they are quite similar.  Up till now, various hypotheses have attempted to link technologies and localities of pre-historic archaeological cultures to that of reconstructed PIE.  Whatever the correctness of the previous hypotheses, this is an entirely new twist combining DNA with other fields of study.

Fig 6.  Alburg cemetary relations

The implications go beyond simply guessing at what language a certain group of people spoke.  Instead it brings us back to the strength of the Beakers and what was it specifically that caused the success of the Proto-Indo-Europeans in their spread across vast stretches?  What was it that caused the nearly uniform y-chromosome changes, as we see in completely M269 Irlbach and Alburg?

I have mentioned before that horses, wagons, metal, dairy, etc, are unlikely to be the engine of this expansion.  Rather, the answer is before us in this study.  Monogamy mostly (Heinrich, Boyd, Richerson, 2012).

And the strength of the pack is the life mates and a social system that is well-ordered.

Life-pair Wolf Center
"For the strength of the Pack is the Wolf, and the strength of the Wolf is the Pack."
                                                                                                        -Rudyard Kipling


  1. I don't think broad conclusions about monogamy are justified based upon two small cemeteries. Even in societies that are polygamous, only about 5% of men have more than one wife. The overall rate of expansion of distinctive Bell Beaker alleles point to a natural increase rate not inconsistent with polygamy and polygamy or its close cousins were well attested in some societies in which there had been recent, near total population replacement by Bell Beaker people, like Bronze Age and Iron Age Ireland.

    Also, even in monogamous societies, serial monogamy which has a similar population genetic effect was common in monogamous societies into the 1800s CE, because women tended to be pretty much continuously pregnant or nursing during their fertile years and the risk of death in childbirth was so high.

    These days, women routinely have great life expectancies than men, resulting in a huge ratio of widows to widowers. But, prior to the 1800s, the reverse was true. Many men lost wives in childbirth and remarried, causing widowers to greatly outnumber widows. This was a phenomena that affected every social class. If you read biographies of senior politicians, aristocrats and professionals like professors, scientists and mathematicians from these eras, the number of deaths in childbirth was huge and almost everyone had siblings who didn't live to adulthood.

    1. I don't mean to suggest it's conclusive, but it's probable that similar results will be replicated where cemeteries are able to support the effort, or by other methods, and these cemeteries represent a snapshot of a much larger cultural system.

      "The overall rate of expansion of distinctive Bell Beaker alleles point to a natural increase rate not inconsistent with polygamy"

      I honestly can't evaluate that statement one way or the other. Maybe someone else can?

      I agree with your statement that polygamy is generally less common even in societies that tolerate it. Humans are evolved for monogamy so I think this is a question of degrees of paternal investment and marital devotion.

      I also expect political marriage to add more than one wife to very important men, but those may be exceptional cases.

    2. You don't need polygamy to generate massive population explosion - just survival and fertility. If each R1b-P312 male had 12 children (6 sons) by the same wife or serial wives, this would generate nearly 1.7 million P312 males within 8 generations (200 or so years).

      I tend towards your perspective, that success was built on a combination of wolf and pack (the fusion of a powerful hunter culture with a stable, conformist, teamwork culture). My suggestion would be that this hybrid culture arose in the Balkan Chalcolithic, migrated across Southern and South Central Europe, developed substantially in Western Europe, and that P312 Bell Beaker was one of its most successful manifestations.

    3. Another couple of notable aspect of the dominance of Bell Beaker genetics in community population genetics are the following: (1) within Bell Beaker households people with recent migrant ancestry had significantly better health and longevity than people with local ancestry, suggesting that locals were servants living under inferior conditions, and (2) lactase persistence genes were present at much higher rates in people with lots of Bell Beaker ancestry than it was in people without it, and an ability to drink cow's milk as an adult may have contributed to the survival of people with the genes and in particular to the likelihood that pregnant and nursing women survived and carried pregnancies to term having health infants, during a time period when irregular bouts of food scarcity for significant periods of time were common, relative to people with only local ancestry who lacked the ability to drink cow's milk as an adult which mattered particularly for pregnant and nursing women when food was scarce.

      I think it is otherwise hard to figure out why the LP gene would show such extremely intense signs of selection for it, otherwise almost unprecedented in human history in such a short period of time.

  2. Why is it a surprise Bell Beaker was monogamous? Monogamy is by definition the standard for most human societies around the world. I think maybe moral relativist have made us think somehow made us think monogamy is not 'normal.' Even, in societies with polygamy, most marriages don't have multiple wives.

    1. Totally agree.

      I was poking at the notion that the explosion of R1b lineages, or any of the explosive male lineages(R1a, O-M122, etc), is the result of widespread polygamy or rape, etc.

      I think a particular dedication of paternal investment and very stable family structures produces the biggest results in Y-chromosome turnover, coupled with other factors, such as a society that is defined by relationships among males.

  3. I've looked into details of Bell Beaker and Early Bronze age families....

    It's almost impossible to definitively say what the family tree looks like. But, a consistent trend I've noticed in most burials is uncles buried with many of their nephews/nieces. Most burials have this. The uncle's sibling (who is the parent of nephews/nieces) is not there. Because, of this it looks like the uncle-nephew/niece combo could be intentional. But, this is just speculation as it is really hard to determine the exact family tree relationship.

    But what is certainly true is there are a lot of sibling groups in the burials but the parents of those sibilings is almost always never in the burial. But, they usually have a male 2nd-degree relative near them (their uncle).

    1. This custom seems to be similar to the Celtic/Irish custom of Fosterage...