Dairy pastoralism sustained eastern Eurasian steppe populations for 5,000 years

Abstract

Dairy pastoralism is integral to contemporary and past lifeways on the eastern Eurasian steppe, facilitating survival in agriculturally challenging environments. While previous research has indicated that ruminant dairy pastoralism was practiced in the region by circa 1300 BC, the origin, extent and diversity of this custom remain poorly understood. Here, we analyse ancient proteins from human dental calculus recovered from geographically diverse locations across Mongolia and spanning 5,000 years. We present the earliest evidence for dairy consumption on the eastern Eurasian steppe by circa 3000 BC and the later emergence of horse milking at circa 1200 BC, concurrent with the first evidence for horse riding. We argue that ruminant dairying contributed to the demographic success of Bronze Age Mongolian populations and that the origins of traditional horse dairy products in eastern Eurasia are closely tied to the regional emergence of mounted herding societies during the late second millennium BC.

Extended Data Fig. 1. Milk and bulk deamidation and peptide counts

Figure 1. Ruminant and equine dairying in prehistoric Eurasia and contemporary Mongolia.

(a) Map of Eurasia showing major geographical features referred to in the text and sites where evidence of dairying has been previously found using proteomic approaches: (1) Khövsgöl, (2) Xiaohe, (3) Gumugou, (4) Subeixi, (5) Bulanovo, (6) Hatsarat, (7) Çatalhöyük West (8), Tomb of Ptahmes, (9) Szöreg-C (Sziv Utca), (10) Olmo di Nogara. Locations for the earliest evidence of ruminant dairying based on the presence of milk fats in ceramics is shown in blue and the earliest evidence of horse dairying shown in pink. Details for each site included in this figure are referenced in Supplementary Table S3. (b-f) Mongolian dairy products from Khövsgöl aimag and (g) dairying rituals from Dundgobi aimag, Mongolia. (b) Yogurt starter culture, Khöröngö (ХӨрӨнГӨ); (c) curd from reindeer milk, ‘kurd’; (d) dried curd from mixed yak and cow milk, aaruul (ааруул); (e) clotted cream from mixed yak and cow milk, öröm (ӨрӨм); (f) fermented horse milk, airag (аЙраг); and (g) blessing ritual for the first horse airag production of the season.

Figure 2. Mongolian dairy consumption by period

(a) Neolithic to Early Bronze Age; (b) Middle-Late Bronze Age; (c) Iron Age and Early Medieval; (d) Late Medieval. Archaeological site cultural affiliation is indicated by colors and symbols. Solid filled symbols indicate individuals with positive evidence of milk proteins, while symbols bisected with a diagonal line indicate individuals where no milk proteins were identified. Individuals of the same site are contained within brackets. Individual AT-923, associated with Ulaanzuukh, is not directly radiocarbon dated and is not included in this figure. Taxonomic icons only indicate the most specific taxa identified in a phylogenetic branch. The full list of dairy species identified for each individual is listed in Table 1 and Supplementary Data 2. Data used in the creation of this figure is included in Supplementary Table S4.

Figure 3. Alignment of observed BLG peptides for two individuals analysed in this study (AT-233, Mid-Late Bronze Age; and AT-775, Mongol Empire), showing the number of Equus (orange) and ruminant (blue) BLG peptides detected.

For Equus, peptides from both BLG1 and BLG2 paralogs are displayed (see Supplementary Table S5 for data associated with figure). Where peptides from these two taxa overlap this has been indicated by a blue/orange cross-hatch pattern. The arrow in Individual AT-775 indicates two contiguous but independent peptides. Beneath each individual is a consensus sequence of Bos taurus BLG (UniProt: P02754) and Equus caballus BLG1 (UniProt: P02758) with dark grey indicating sequence identity, and pale grey indicating sites with sequence differences.

Figure 4. Timeline of evidence for the consumption of different livestock milk in prehistoric and historic Mongolia.

Radiocarbon dates for each individual were calibrated using OxCal (OxCal v4.3.2 Bronk Ramsey; r:5 IntCal13 atmospheric curve) and resulting radiocarbon probabilities were grouped by the taxa of dairy proteins identified in that individual (indicated by AT- numbers), with ruminant taxa (Ovis, Capra and Bovinae) indicated in purple, Equus indicated by orange and Camelus indicated by green. Dairy peptides identified in individual AT-26 (indicated with an asterisk) are specific to Bovinae/Ovis. Individuals without direct radiocarbon dates are indicated by unfilled boxes and are placed on the timeline based on the estimated time spans for the Xiongnu and Mongol Empires. For data used in this figure, refer to Supplementary Table S6.