A Journal of People report
Stone tools uncovered in Mongolia by an international team of archaeologists indicate that modern humans traveled across the Eurasian steppe about 45,000 years ago, finds a new University of California, Davis, study. The date is about 10,000 years earlier than archaeologists previously assumed.
The site also points to a new location for where modern humans may have first encountered their mysterious cousins, the now extinct Denisovans, said Nicolas Zwyns, an associate professor of anthropology and lead author of the study.
Zwyns led excavations from 2011 to 2016 at the Tolbor-16 site along the Tolbor River in the Northern Hangai Mountains between Siberia and northern Mongolia.
The age of the site – determined by luminescence dating on the sediment and radiocarbon dating of animal bones found near the tools – is about 10,000 years earlier than the fossil of a human skullcap from Mongolia, and roughly 15,000 years after modern humans left Africa.
The excavations yielded thousands of stone artifacts, with 826 stone artifacts associated with the oldest human occupation at the site.
With long and regular blades, the tools resemble those found at other sites in Siberia and Northwest China – indicating a large-scale dispersal of humans across the region, Zwyns said.
“These objects existed before, in Siberia, but not to such a degree of standardization,” Zwyns said. “The most intriguing (aspect) is that they are produced in a complicated yet systematic way — and that seems to be the signature of a human group that shares a common technical and cultural background.”
That technology, known in the region as the Initial Upper Palaeolithic, led the researchers to rule out Neanderthals or Denisovans as the site’s occupants.
“Although we found no human remains at the site, the dates we obtained match the age of the earliest Homo sapiens found in Siberia,” Zwyns said. “After carefully considering other options, we suggest that this change in technology illustrates movements of Homo sapiens in the region.”
Their findings were published online in an article in Scientific Reports (Nicolas Zwyns, Cleantha H. Paine, Bolorbat Tsedendorj, Sahra Talamo, Kathryn E. Fitzsimmons, Angaragdulguun Gantumur, Lkhundev Guunii, Odsuren Davakhuu, Damien Flas, Tamara Dogandžić, Nina Doerschner, Frido Welker, J. Christopher Gillam, Joshua B. Noyer, Roshanne S. Bakhtiary, Aurora F. Allshouse, Kevin N. Smith, Arina M. Khatsenovich, Evgeny P. Rybin, Gunchinsuren Byambaa, Jean-Jacques Hublin. The Northern Route for Human dispersal in Central and Northeast Asia: New evidence from the site of Tolbor-16, Mongolia. Scientific Reports, 2019; 9 (1) DOI: 10.1038/s41598-019-47972-1)
Evidence of soil development (grass and other organic matter) associated with the stone tools suggests that the climate for a period became warmer and wetter, making the normally cold and dry region more hospitable to grazing animals and humans.
Preliminary analysis identifies bone fragments at the site as large (wild cattle or bison) and medium size bovids (wild sheep, goat) and horses, which frequented the open steppe, forests and tundra during the Pleistocene – another sign of human occupation at the site.
The dates for the stone tools also match the age estimates obtained from genetic data for the earliest encounter between Homo sapiens and the Denisovans.
“Although we don’t know yet where the meeting happened, it seems that the Denisovans passed along genes that will later help Homo sapiens settling down in high altitude and to survive hypoxia on the Tibetan Plateau,” Zwyns said. “From this point of view, the site of Tolbor-16 is an important archaeological link connecting Siberia with Northwest China on a route where Homo sapiens had multiple possibilities to meet local populations such as the Denisovans.”
Co-authors of the paper include UC Davis anthropology graduate students Roshanne Bakhtiary and Kevin Smith, former graduate student Joshua Noyer, and undergraduate alumna Aurora Allshouse, now a graduate student at Harvard University.
Other members of the team included colleagues from universities and institutes in South Carolina, the United Kingdom, Mongolia, Germany, Belgium and Russia.
Oldest evidence of dairying on the East Asian Steppe
Two thousand years before the armies of Ghengis Khan, populations in Mongolia were already living a pastoralist, dairying lifestyle – similar to that which would enable future populations to conquer most of Asia and Europe. Although pastoralism has long been the primary means of subsistence on the East Asian steppe, the origins of this tradition have been unclear. Now, an international team of researchers has uncovered the earliest direct evidence to date of dairying in Mongolia – around 1300 BC – by tracking milk proteins preserved in tooth tartar. The livestock that were milked – cattle, sheep and goats – are not native to the region and were likely introduced by Western Steppe herders. (Choongwon Jeong, Shevan Wilkin, Tsend Amgalantugs, Abigail S. Bouwman, William Timothy Treal Taylor, Richard W. Hagan, Sabri Bromage, Soninkhishig Tsolmon, Christian Trachsel, Jonas Grossmann, Judith Littleton, Cheryl A. Makarewicz, John Krigbaum, Marta Burri, Ashley Scott, Ganmaa Davaasambuu, Joshua Wright, Franziska Irmer, Erdene Myagmar, Nicole Boivin, Martine Robbeets, Frank J. Rühli, Johannes Krause, Bruno Frohlich, Jessica Hendy, Christina Warinner. Bronze Age population dynamics and the rise of dairy pastoralism on the eastern Eurasian steppe. Proceedings of the National Academy of Sciences, 2018; 201813608 DOI: 10.1073/pnas.1813608115)
However, ancient DNA evidence from Bronze Age Mongolians indicates minimal genetic contributions from Western Steppe herders, suggesting that the livestock and dairying technologies were transferred by cultural processes rather than a major population migration, in contrast to the pattern seen in Europe. The findings are published in PNAS.
Cultural and Technological Transfer without Population Replacement
Researchers analyzed human remains from six sites in northern Mongolia associated with the Deer Stone-Khirigsuur Complex (DSKC).
“The DSKC is well-known for their monumental architecture, including upright stones with deer and other motifs, and large stone mounds, often associated with one or more human burials,” explains co-first author Shevan Wilkin of the Max Planck Institute for the Science of Human History. “In some locations, these structures are highly conspicuous and visible from great distances.”
The DSKC is the earliest culture associated archaeologically with pastoralism in Mongolia, with sites containing bones of sheep, goat, cattle and horse as early as the 13th century BC.
However, to date no direct observations of dairy consumption had been made in this area.
The researchers conducted genome-wide analyses on 22 Bronze Age individuals, whose remains were radiocarbon dated to the late Bronze Age, ca. 1300-900 BC. Whole genome sequencing was further performed on two of these individuals.
The results of these analyses showed that these Bronze Age Mongolians were genetically distinct from Western steppe herders of the same time, indicating that the appearance of dairying in Mongolia was not the result of population migration and replacement.
“These findings suggest that neighboring Western steppe herders directly or indirectly introduced dairy pastoralism to local indigenous populations primarily through a process of cultural exchange,” explains Choongwon Jeong, co-first and co-senior author, of the Max Planck Institute for the Science of Human History. “We don’t see evidence for the kind of large-scale population replacement by Western Steppe herders that has been observed in Bronze Age Europe or in the nearby Altai-Sayan region.”
Evidence of Dairy Consumption
The researchers also analyzed the dental calculus of nine individuals using proteomics. Milk proteins were found in the calculus of seven individuals, confirming that dairy products were consumed as early as 1300 BC. Both whey and curd proteins were recovered, and could be identified as coming from sheep, goats and cattle.
Interestingly, none of the individuals was lactase persistent – genetically capable of digesting the milk sugar lactose. Most Mongolians today are also not lactase persistent, despite consuming a large proportion of their diet as dairy products.
“The 3,000-year legacy of dairy pastoralism in Mongolia poses challenging questions to grand narratives of human adaptation and natural selection,” explains Christina Warinner, senior author, of the Max Planck Institute for the Science of Human History. “As a non-lactase persistent dairying society with a rich prehistory, Mongolia can serve as a model for understanding how other adaptations, such as cultural practices or microbiome alterations, may be involved in enabling and maintaining dairy-based cuisines around the world.”