On March 2, Nature Ecology & Evolution published a research paper entitled "Dairy pastoralism sustained eastern Eurasian steppe populations for 5,000 years" (Wilkin et al., 2020) of the Institute of Human History Sciences of the Max Planck Society. Prof. YANG Yimin at University of Chinese Academy of Sciences was invited to write the commentary article of Wilkin and his team’s work. The article entitled "Dairying transformed Mongolia" is published in Nature Ecology & Evolution on March 2.
Proteomic analysis of human dental calculus finds evidence that ruminant dairying was accompanied with eastward human migration into Central Mongolia about 5,000 years ago and horse milk consumption was a part of the economic transformation in Mongolia around 1200 bc.
Although all mammals produce milk, humans are the only species to consume milk from other animals, a practice that may have started as far back as 10,500 years ago in the Middle East1. It is thought that dairying of domestic ruminant animals (sheep, goats and cattle) spread with agriculture across Europe by about 8,000 years ago, when the earliest evidence of cheese-making appears2; while dairying was being practiced in Saharan Africa 7,000 years ago3. By about 5,500 years ago, domesticated horses were ridden and milked in Botai, northern Kazakhstan4. We know that herding brought by the Afanasievo culture became the core component of subsistence strategy in the eastern Eurasian steppe, producing primary animal products (meat, hide and bone) which have been widely exploited over the past 5,000 years, but we are less sure about whether secondary (renewable) animal products such as milk were harvested since the beginnings of pastoralism in the region. In this issue of Nature Ecology & Evolution, Wilkin et al. (2019)." id="ref-link-section-d69608e286" style="background-color: transparent; box-sizing: inherit; color: rgb(0, 102, 153); overflow-wrap: break-word; text-decoration: none; vertical-align: baseline;" aria-label="Reference 5" href="https://www.nature.com/articles/s41559-019-1082-0#ref-CR5" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref">5 present directly dated and chemical evidence of ruminant milk consumption associated with early herding practices in the late fourth millennium bc in Central Mongolia.
Archaeological scientists usually identify milk consumption through analysis of lipids in the form of fatty residues preserved in the pottery that once contained the dairy products. Lipid analysis can identify the presence of milk, but cannot refine the animal origin of that milk. Ascertaining dairying practices can also be achieved from inferring the structure of herds through zooarchaeological skeletal analysis, but this needs a large number of bone assemblages to accurately describe mortality profiles. However, proteomic analysis of milk residues preserved in human dental calculus (hardened tooth plaque) can fill in these gaps6, which is very useful in contexts where pottery and/or animal bones are rare or absent. Wilkin et al. used proteomic analysis of dental calculus to describe the dynamics of dairying in Central Mongolia from the early Bronze Age (~3300 bc) to the Mongol period (ad ~1206–1398), providing information about chronological variation of dairy animal exploitation, as well as fluctuating economic and social patterns in the eastern Eurasian steppe. In combination with direct radiocarbon dating of human bones, this method helps draw the spatio–temporal routes of dairying’s spread across the world, and firmly places milk alongside starchy crops as one of the earliest cases of food globalization.
Wilkin et al. discovered evidence for bovine, ovine or caprine milk consumption among people associated with the Afanasievo or Chermurchek cultural complex of ruminant herding and early bronze working, in one sample dated between 3316–2918 bc in Central Mongolia, as well as in one sample dated between 3310–2919 bc in the Mongolian part of the Altai mountains. These dates coincide with the appearance of the originally eastern European Afanasievo culture in the Altai mountains dated to 3100–2900 bc7, indicating that dairying accompanied the introduction of domestic ruminant animals into the eastern Eurasian steppe. Thus, this suggests that milking spread more than 7,000 km from the Middle East, through eastern Europe, to the eastern Eurasian steppe along with herding over a period of about 5,000 years, before first appearing in southern Xinjiang, China, around 1900 bc8, with adoption increasing towards the final part of the Bronze Age. While herding of ruminant animals was widely adopted in the semi-arid and semi-humid regions of northern China more than 4,000 years ago, whether dairying was practiced with pastoralism in this region still remains an open question.
The fact that Wilkin and colleagues find evidence for horse milk consumption in the eastern Eurasian steppe from the late Bronze Age (~1200 bc) onward, coincident with the expanding use of horses for multiple purposes, including ritual, bridling and riding as well as human diet, could reflect the economic transformation from a more sedentary agro-pastoralism to nomadic pastoralism. By the time of the eastern Eurasian Xiongnu empire (~200 bc), horse milk residues dominate the samples, indicating the increasingly important role of horses in what we know was a nomadic society. As such, the prominent detection of horse milk residue in human dental calculus could even be regarded as a marker of a nomadic population in the Iron Age.
Wilkin and colleagues provide new clues for the timing and pathways of spread of domestic cattle and sheep from their origins in the Middle East into China. In the late fourth millennium bc, the earliest domestic cattle in China appear in the Gan-Qing area9 and northeast China10, and the earliest domestic sheep are also found in the Gan-Qing area11. The detection of milk residue confirms the herding of cattle and sheep around 5,000 years ago in Mongolia (2019)." id="ref-link-section-d69608e354" style="background-color: transparent; box-sizing: inherit; color: rgb(0, 102, 153); overflow-wrap: break-word; text-decoration: none; vertical-align: baseline;" aria-label="Reference 5" href="https://www.nature.com/articles/s41559-019-1082-0#ref-CR5" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref">5, yet herding was absent at that time in Xinjiang, northwestern China, the region connecting the Gan-Qing area and Central Asia; this suggests that Mongolia could have been the gateway into China for the eastward spread of cattle and sheep (Fig. 1). Recently, millet cultivation in southeastern Kazakhstan could be traced back to ~2700 bc12, far from the domestication centres in northern China. But there is also no report of contemporary millet cultivation in Xinjiang; thus, the westward spread of millet might mirror the eastward spread of cattle and sheep, implicating the eastern Eurasian steppe as a potential crossroads for crops and livestock. The human carriers of cattle, sheep and millet, and the detailed pathways they followed will need to be clarified by multi-disciplinary research in the future.
Source: Nature ecology & evolution
