Ecological evaluation of the development of Neanderthal niche exploitation

Abstract

Understanding the ecological niche occupied by Neanderthals and their ancestors is at the forefront of many Palaeolithic investigations. In this study, a complex characterization of the environments once occupied by these hominins in Western Eurasia were performed. It included the determination of the biome and climatic zones occupied, the potential wind exposures, the classification of the karst regions where they lived, the direction of the entrance of caves inhabited and the average daily total solar irradiation values. In addition, the climatic suitability of the Mediterranean mosquito fauna, tick-borne encephalitis and four large mammal species as potential mammal hosts were also studied. It was found that Western Eurasian hominins occupied a wide ecological niche range from the semi-arid to the subarctic climates. Between the MIS20-MIS4 interval, the biomes occupied by Neanderthals and their ancestors shifted from the woodland-shrubland to the boreal biomes, indicating the increasing general biocultural adaptation to the more continental environments. These populations inhabited territories with weak to moderate wind exposure (Beaufort 2–5) and usually occupied caves with a south or southwest-oriented entrance. This habitat selection indicates the recognition of local microclimatic factors and a conscious choice of shelters. In the glacial periods, the increasing extension of temperate-subpolar karst regions at the expense of the more habitable subtropical karst areas might have adversely affected the overwintering chances of ancient western Eurasian populations in West, Central Europe, and Central Asia. The supraorbital area of ancient hominins with low receding foreheads and prominent supraorbital ridges may have been exposed to a greater risk of the development of frontal sinusitis and its complications than modern humans with more gracile skulls. Neanderthals and their predecessors were exposed to moderate average daily solar radiation values, although these values exhibit heterogenic picture in the comparison of Central and Southern Europe. While the southern European Neanderthal populations were dominantly exposed to the risk of mosquito-borne diseases, the northern and central populations could suffer from tick-borne diseases. However, both tick-borne encephalitis virus and its medium-large mammal hosts were present in most sites dwelled by Neanderthals and their ancestors.