The first evidence of horse dairying in the Altai region of central Asia dates back to around 1350 BCE, researchers report, based on protein analysis of human remains.
Ruminants had been milked by inhabitants of the region long before they added horses as a milk source, Alicia Ventresca Miller and her fellow researchers reported in the journal PLOS ONE.
Located in the heart of Asia, the Altai Mountains form a frontier between the western and eastern steppe, dividing distinct ecologies and populations.
The ecology of this mountainous zone separates the lowlands of Kazakhstan and western Siberia, where climates are continental, from the higher elevation, and colder and drier climate, found in Mongolia.
Neither a restrictive barrier nor a freely open corridor, the Altai region has instead long acted as an area enabling certain types of intersections and connections, but reducing opportunities for others.
Before around 3500 BCE, hunter-gatherer-fisher groups were separated, both geographically and genetically, by the Altai Mountains. During the Bronze Age, from 3500 BCE to 900 BCE, populations moved into and across the mountain range in multiple waves, from regions to the west and southwest.
The researchers said the initial movement of herders and livestock into the eastern steppe is of great interest, as this region has long been home to pastoralist groups.
However, because of the lack of animal remains, it has been difficult to discern the timing of the adoption of domesticated ruminants and horses into the region, though recent research on ancient dairying has started to shed new light on this history.
The study team looked for proteins in dental calculus from 21 ancient human remains to identify shifts in dairy consumption in the Altai Mountains, as well as drawing on evidence from sites dating from the Early Bronze to the Late Iron Age. About two-thirds produced protein signatures useful for interpretation.
They compared these finds with evidence for the rise of social complexity in western Mongolia, as reflected in material remains signaling population growth, the establishment of structured cemeteries, and the erection of large monuments.
Their results suggest that the subsistence basis for the development of complex societies began at the dawn of the Bronze Age, around 3500 BCE, with the adoption of extensive, multi-species dairying involving ruminant livestock.
“Together with previously reported data from the region, they also point to widespread consumption of milk amongst Altai populations throughout the later Bronze Age.”
Analysis of dairy peptides shows that sheep, goat, cattle and horses were all being milked in the region, as was also the case during the Bronze Age in the Pontic-Caspian region far to the west.
The identification of the earliest horse milk peptides in the region pushes back the evidence for horse milk drinking amongst Altai populations to around 1350 BCE.
“When analyzed in tandem with evidence from well-documented archaeological sites, as well as recent ancient DNA results, these proteomic findings provide useful new data for assessing broader dietary and economic changes.”
The archaeological record of pre-pastoral hunter-gatherer-fisher groups in the Mongolian Altai before 3500 BCE is reflected in surface scatters of lithics and ceramics, which provide evidence for residential areas, but no pithouses or other structures.
Beginning around 3000 BCE, or earlier, the first herders and their ruminants crossed geographic and cultural boundaries, bringing knowledge of livestock management and milking into Mongolia.
The researchers said that investments in pastoralism intensified over time, enabling a food production system that sustained growing populations.
While pronounced social changes and monumental constructions occurred in tandem with the first evidence for horse dairying, around 1350 BCE, these shifts were fueled by a long-term economic dependence on ruminant livestock.
“Therefore, the spread into the Mongolian Altai of herds, and then horses, resulted in immediate dietary changes, with subsequent social and demographic transformations occurring later.”
The earliest identified horse milk drinkers in the region belonged to the Sagsai culture. “Our identification of the earliest direct evidence for horse dairy consumption among two Sagsai individuals highlights the importance of the Middle Bronze Age as a formative period,” they said.
“While the timing of early horse dairying coincides with the construction of Sagsai cemeteries, it is clear that horses were relatively novel and not an economic mainstay of these economies.
“Domesticated horses occupied a primary role in ritual life, yet ruminant livestock were the foundation of pastoralist subsistence economies that drove population growth and the rise of monumental architecture.”
The authors noted that peaks in social complexity are often driven by long-term growth in human populations that occur after subsistence diversification.
Cultural tipping points, or flash points, are associated with shifts in cosmology, climate, or the introduction of new technologies.
“In the Altai, this tipping point occurred as a result of multiple waves of human populations and accompanying ruminants moving across the steppe and Altai Mountains into new ecological zones inhabited by hunter-gatherer-fisher populations.
“While these new pastoral foodways eventually increased economic stability, there was a maturation period between the initial adoption of domesticated livestock and the viable management of herds.
“The integration of herds into societies was a gradual process, during which populations grew and herds expanded.
“Over long time scales, advances in technologies and knowledge supported the management and survival of livestock.”
Population growth is tied to economic advances, they said, which permitted an increase in the number and scale of monumental complexes.
“As such, the Mongolian Bronze Age stands as a formative period for the rise of social complexity in eastern Eurasia.”
The study team comprised Ventresca Miller, Shevan Wilkin, Jessica Hendy, Tsagaan Turbat, Dunburee Batsukh, Noost Bayarkhuu, Pierre-Henri Giscard, Jan Bemmann, Jamsranjav Bayarsaikhan, Bryan Miller, Julia Clark, Patrick Roberts and Nicole Boivin, variously affiliated with a range of institutions in Europe, Asia and the United States, including the Max Planck Institute for the Science of Human History in Germany, the University of Michigan, and the National University of Mongolia.
Ventresca Miller AR, Wilkin S, Hendy J, Turbat T, Batsukh D, Bayarkhuu N, et al. (2022) The spread of herds and horses into the Altai: How livestock and dairying drove social complexity in Mongolia. PLoS ONE 17(5): e0265775. https://doi.org/10.1371/journal.pone.0265775