Featuring hominins as actors in the MPR scenarios

Abstract

The Mid-Pleistocene Revolution (MPR) was a period of profound ecosystem reconfiguration around 1 Ma. It is generally accepted that those environmental changes affected the survival opportunities and the distribution patterns of humans in Europe. Modeling the behavioural responses of humans to the changing environments of the MPR entails the energetic characterization of hominins. By “energetic characterization” we mean that it is necessary to infer their daily energetic requirements as well as their energetic expenditure. The energetic requirements of a hominin are determined by its palaeophysiology, and they are mainly affected by the species body size, but also vary with age, sex and physiological stage. However, palaeophysiology also affects the energetic cost of the daily activities necessary to survive and reproduce. The energetic requirements of ancient hominins may be estimated by extrapolation of the predictive equations experimentally developed for recent humans and based on body size, age and sex. Concerning the cost of daily activities, however, a specific research program on experimental energetics is required. That experimental program should involve the re-enactment of the basic daily activities of a hunter-gatherer in a number of volunteers to measure their energetic cost and to identify the possible influence of body composition and architecture on the energetic expenditure. Eventually, those experimental data may be extrapolated to ancient hominins. Such an experimental research program is currently under development at CENIEH. The activities recreated up to date include the catchment of raw materials (Vidal-Cordasco et al. 2017a), gathering of vegetable resources (Prado-Nóvoa et al, 2017a), and stone knapping (Mateos et al. 2018). Other experimental studies were carried out to estimate the cost of walking and burden transport during foraging activities (Vidal-Cordasco et al, 2017b). Additional research, currently under development, include the energetic expenditure of butchering animal carcasses and digging in search of underground plant resources , as well as further experiments on locomotion. All these experiments are performed by individuals of different ages (adults, adolescents and children), both genders and in different reproductive stages (e. g. pregnant and lactating women), since all those factors affect energetic expenditure. The objective of this ambitious research program is to establish the daily energetic expenditure profile of any individual in a hunter-gatherer population as a function of its age, sex and physiological stage.