Today, the people of the Eurasian steppe get more than half their calories from dairy during the summer months. Photo by Björn Reichhardt
March 2 (UPI) -- Archaeological evidence suggests dairy pastoralism originated in southwest Asia. How and when the tradition migrated eastward is less understood.
The discovery of 5,000-year-old milk proteins -- described Monday in the journal Nature Ecology and Evolution -- suggests populations living on the Eurasian steppe were producing and consuming milk as early as 3,000 B.C.
The Eurasian steppe's strong winds weathered away much of the evidence of the pastoral populations that occupied prehistoric Mongolia. To better understand the evolution of these early pastoralists, researchers examined a series of ritual human burial mounds.
Scientists analyzed the chemical makeup of dental calculus, or plaque, extracted from human teeth dated from the Early Bronze Age to the Mongol Period. More than three-quarters of the individuals tested revealed evidence of dairy consumption.
The extensive nature of the milk consumption suggests the practice was introduced even earlier than 3,000 B.C.
Previous genetic surveys have linked the people of prehistoric Mongolia with herder populations of the western steppe. The connection suggests populations from Russia's Atlai mountains likely brought dairy pastoralism with them as they traveled east.
"Modern Mongolians use cow, sheep, goat, yak, camel, horse and reindeer for milk today, yet when each of these species were first utilized for dairy in Mongolia remains unclear," lead study author Shevan Wilkin, researcher at the Max Planck Institute for the Science of Human History in Germany, said in a news release. "What is clear is that the crucial renewable calories and hydration made available through the incorporation of dairying would have become essential across the arid and agriculturally challenging ancient Eastern Steppe."
Analysis of the ancient plaque showed the earliest milk drinkers in prehistoric Mongolia sourced their dairy from ruminant species, like cattle, sheep and goats. Scientists found the chemical signatures of horse milk consumption in the plaque extracted from teeth dating to 1,200 B.C. The analysis also showed camel milk consumption was popular during the Mongol Empire, between 1,400 and 1,200 B.C.
"We are excited that through the analysis of proteins we are able to see the consumption of multiple different animal species, even sometimes in the same individual," said senior study author Jessica Hendy. "This gives us a whole new insight into ancient dairying practices."
Researchers hope further analysis will help them determine how exactly western steppe herders helped spread the tradition of dairy pastoralism through the region.