Morphological features of the Eneolithic — Early Bronze population as a result of adaptation to the geographical and bioclimatic conditions of the Altai highlands

This paper is aimed at scrutinizing the dependence between the morphological features of the Eneolithic — Early Bronze population and the geographical and bioclimatic conditions in the Altai valleys and intermountain basins. Across the territory of the Altai highlands, we have identified several local-territorial groups of archaeological sites dating to the period under study. Most of them belong to the Afanasyevо culture, with the rest being represented by the Kurota, Aragol and Ulita cultural types that have been recently designated from the Afanasyevо culture. For each group, in accordance with their geographical localization, we have calculated geographical and bioclimatic parameters. The comparison of these parameters with the characteristics of the corresponding craniological series has allowed us to reveal the main trends of intergroup variability within the Eneolithic — Early Bronze Altai population. A considerable and statistically significant correlation is found between the morphological parameters, such as the height of the cranium, general sizes of a cranial cavity and the width of the face, and geographic and bioclimatic parameters characterizing the severity of the climate and the mountain height above sea level. In terms of other race-demarcating characteristics, no significant difference has been revealed between the territorial groups of the Altai Eneolithic — Early Bronze population characterized by the proto-European type. The identified variations correspond to the previously established differences between the total series of skulls of the Afanasyevо culture from the Altai highlands and the Minusinsk Hollow, as well as to two craniological types defined as the main anthropological components of the Afanasyevо culture population in Southern Siberia. The first of these types, prevailing among the Altai Afanasyevo culture population, is markedly hypermorphic and characterized by a higher and, in general, a larger skull. The second type, determining the craniological specifics of the unicultural population in the Minusinsk Hollow, is moderately hypermorphic and characterized by a smaller and, importantly, less high skull. Our findings suggest that these differences are associated in many respects with a general increase in the body size in populations having lived in the most bioclimatically unfavourable areas of the Altai highlands. This is evidenced by an increase in the longitudinal and girth dimensions of the long skeletal bones of the Altai Eneolithic — Early Bronze population having inhabited the mid-mountain and high-mountain Altai areas compared with the control samples from the low-mountain Altai regions and the Afanasyevo culture from the Minusinsk Hollow. Therefore, according to the calculated parameters, the population from the bioclimatically unfavourable Altai regions was characterized by a rather large weight and height among all the studied ancient Neolithic — Bronze Eurasian groups. Thus, our study confirms that the main mechanism of biological adaptation to the severe mountain environment of the Altai highlands among the Eneolithic — Early Bronze population was the enhancement of energy processes by means of increasing standard metabolism. As a result, the initially tall and large proto-European population was becoming even larger