Early Mongolian ruminant and horse dairying through ancient protein analysis
Dairy pastoralism is widely practiced in Eurasia today, and our goal was to discover when this subsistence strategy arrived in Mongolia, on the Eastern Eurasian Steppe. While modern Mongolians dairy multiple species, how far these traditions extend into the past has been challenging to uncover.
In late November of 2016, I travelled to the National University of Mongolia in Ulaanbaatar to meet with Prof. Erdene Myagmar to workshop what kind of bimolecular research questions we could apply to the bioarchaeological collections curated within the Department of Anthropology and Archaeology. Our discussions led to the formation of multiple studies regarding the health, diet, economies, ancestry, and cultural evolution of ancient and historic Eastern Steppe populations. For three weeks my colleagues and I shivered in the -25°C winter air on the short walk to the university to work with over 200 previously excavated individuals who lived between 6000 to 600 years ago. We collected samples for stable isotope analysis, AMS radiocarbon dating, ancient DNA, microfossils, and - the focus of this paper - ancient proteomics.
Picture of our frozen eyelashes after walking a short 3 blocks to dinner when it was -30°C (Shevan Wilkin and Madeleine Bleasdale).
After extracting and analyzing proteins from dental calculus (calcified dental plaque) samples from the teeth of 32 individuals, we were able to see that most (72%) contained protein evidence for dairy consumption. Not only did we find milk consumption to be extremely common across all time periods, but also that evidence for sheep/cow milk was present in our earliest sample (ca. 3000 BC).
Furthermore, this early individual with proteins from either cow or sheep milk was buried under a Western Steppe style burial mound, suggesting that dairy animals and practices may have been introduced by incoming herding populations, such as the Yamnaya or Afanasievo, who migrated from the west. However, as this was our oldest sample, we cannot discount the possibility that dairying was present in Mongolia before the influx of Western Steppe herders.
Caption: Cows from a domestic dairy herd foraging on the snowy countryside outside of Ulaanbaatar. Photo credit: Shevan Wilkin
Historic accounts from local and foreign observers had detailed the ubiquity of overall milk consumption, as well as the social significance of fermented, alcoholic horse milk in social and political settings. Excitingly, in addition to identifying numerous horse milk proteins in individuals who lived during the horse-reliant Xiongnu and Mongol Empires, we also found overwhelming evidence for horse milk consumption in the Late Bronze Age (ca. 1200 BC), a period that coincides with the first evidence for horseback riding and bridling on the Eastern Steppe.
Caption: Handmade dairy products sun-drying on top of a ger, a typical, transportable Mongolian home used by mobile pastoralists. Products like those seen drying here can last up to two years at room temperature. Photo credit: Shevan Wilkin
Cow, yak, sheep, goat, horse, reindeer, and camel milk consumption remain enormously important across Mongolia today, and traditionally produced dairy products continue to hold a strong cultural significance. It has been incredible experience to discover and share the time depth of dairying practices with modern Mongolian herders and dairy consumers. In addition to this, a member of one of our associated projects, Zoljargal Enkh-Amgalan, translated our paper into Mongolian as part of another community post. As this study has increased our understanding of dairying on the far Eastern Steppe, we hope that in the future additional studies will illuminate the pathway(s) upon which dairying practices were transferred from Neolithic Southwest Asia and into Mongolia over 3000 years ago.
For Mongolian translation of the full paper, please go to: https://natureecoevocommunity.nature.com/users/348900-shevanwilkin/posts/59870-mongolian-translation-of-dairy-pastoralism-sustained-eastern-steppe-populations-for-5000-years