Milk enabled massive steppe migration

Date:
September 15, 2021
Source:
Max Planck Institute for the Science of Human History
Summary:
The long-distance migrations of early Bronze Age pastoralists in
the Eurasian steppe have captured widespread interest. But the
factors behind their remarkable spread have been heavily debated by
archaeologists. Now a new study provides clues regarding a critical
component of the herders' lifestyle that was likely instrumental
to their success: dairying.



FULL STORY ==========================================================================
The long-distance migrations of early Bronze Age pastoralists in the
Eurasian steppe have captured widespread interest. But the factors behind
their remarkable spread have been heavily debated by archaeologists. Now
a new study in Nature provides clues regarding a critical component of
the herders' lifestyle that was likely instrumental to their success:
dairying.


==========================================================================
From the Xiongnu to the Mongols, the pastoralist populations of the
Eurasian steppe have long been a source of fascination. Amongst the
earliest herding groups in this region were the Yamnaya, Bronze Age pastoralists who began expanding out of the Pontic-Caspian steppe
more than 5000 years ago. These Bronze Age migrations resulted in gene
flow across vast areas, ultimately linking pastoralist populations in Scandinavia with groups that expanded into Siberia.

Just how and why these pastoralists travelled such extraordinary
distances in the Bronze Age has remained a mystery. Now a new study led
by researchers from the Max Planck Institute for the Science of Human
History in Jena, Germany has revealed a critical clue and it might come
as a surprise. It appears that the Bronze Age migrations coincided with
a simple but important dietary shift - - the adoption of milk drinking.

The researchers drew on a humble but extraordinary source of information
from the archaeological record -- they looked at ancient tartar (dental calculus) on the teeth of preserved skeletons. By carefully removing
samples of the built-up calculus, and using advanced molecular methods
to extract and then analyse the proteins still preserved within this
resistant and protective material, the researchers were able to identify
which ancient individuals likely drank milk, and which did not.

Their results surprised them. "The pattern was incredibly strong,"
observes study leader and palaeoproteomics specialist Dr. Shevan Wilkin,
"The majority of pre-Bronze Age Eneolithic individuals we tested -- over
90% -- showed absolutely no evidence of consuming dairy. In contrast, a remarkable 94% of the Early Bronze Age individuals had clearly been milk drinkers." The researchers realized they had uncovered a significant
pattern. They then further analysed the data in order to examine what
kind of milk the herders were consuming. "The differences between the
milk peptides of different species are minor but critical," explains
Dr. Wilkin. "They can allow us to reconstruct what species the consumed
milk comes from." While most of the milk peptides pointed to species like
cow, sheep and goat, which was not surprising in light of the associated archaeological remains, calculus from a couple of individuals revealed
an unexpected species: horse.

"Horse domestication is a heavily debated topic in Eurasian archaeology,"
notes Dr. Wilkin. One site where early Central Asian milk drinking had
been proposed was the 3500-year-old site of Botai in Kazakhstan. The researchers tested calculus from a couple of Botai individuals, but found
no evidence of milk drinking. This fits with the idea that Przewalskii
horses -- an early form of which were excavated from the site --
were not the ancestors of today's domestic horse, as shown by recent archaeogenetic study. Instead, horse domestication -- and the drinking
of horse milk -- likely began about 1500 kilometers to the west in the
Pontic Caspian steppe.

"Our results won't make everyone happy, but they are very clear," says Professor Nicole Boivin, senior author of the study and Director of the Department of Archaeology at the MPI Science of Human History. "We see a
major transition to dairying right at the point that pastoralists began expanding eastwards." Domesticated horses likely had a role to play
too. "Steppe populations were no longer just using animals for meat,
but exploiting their additional properties -milking them and using them
for transport, for example," states Professor Boivin.

What precise critical advantage milk gave remains to be investigated. But
it is likely that the additional nutrients, rich proteins, and source of
fluids in a highly arid environment would have been critical to survival
in the harsh and open steppe. "What we see here is a form of cultural revolution," says Dr.

Wilkin, "Early Bronze Age herders clearly realized that dairy
consumption offered some fundamental benefits and once they did, vast
steppe expansions of these groups across the steppe became possible." ========================================================================== Story Source: Materials provided by Max_Planck_Institute_for_the_Science_of_Human_History.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Shevan Wilkin, Alicia Ventresca Miller, Ricardo Fernandes, Robert
Spengler, William T.-T. Taylor, Dorcas R. Brown, David Reich,
Douglas J.

Kennett, Brendan J. Culleton, Laura Kunz, Claudia Fortes, Aleksandra
Kitova, Pavel Kuznetsov, Andrey Epimakhov, Victor F. Zaibert,
Alan K.

Outram, Egor Kitov, Aleksandr Khokhlov, David Anthony, Nicole
Boivin.

Dairying enabled Early Bronze Age Yamnaya steppe expansions. Nature,
2021; DOI: 10.1038/s41586-021-03798-4 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210915111005.htm

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