Locomotor economy and foraging ecology in hominins

Abstract

The ratio of net energy gained over time expended while foraging (Net Rate of Energy Gain or NREG) or the ratio of net energy gained over energy expended (Foraging Energy Efficiency or FEE) are commonly used measures of foraging success in modern and ancient hunter-gatherers. This work addresses how and to what extent somatic proportions may influence energy gain during foraging trips. An experimental study was carried out on a sample of 46 subjects of both sexes. The tests consisted of walking unladen and carrying 5, 10, and 15 kg in a backpack. Energy expenditure was measured by indirect calorimetry, and the loads were used to simulate carcasses transported. Predictive equations were computed to estimate NREG and FEE from somatic dimensions of some extinct hominin species. Since body mass and femur length affect both NREG and FEE, foraging efficiency could differ between hominin species.