Human energy expenditure and thermoregulation during persistence hunting in the Namib

Chasing prey to exhaustion on foot-persistence hunting-has been hypothesized to play a key role in the evolution of human endurance, energetics, and thermoregulation. However, direct physiological data from such pursuits are lacking, particularly from open arid environments where persistence hunting may have originated. We report the first physiological measurements from an unacclimatized ultrarunner and hunter, accompanied by three acclimatized hunters, during six persistence pursuits of Oryx gazella in the Namib desert. The pursuits spanned 49.5 km on foot in 7.8 hours over 3 days. Two pursuits were successful: A healthy oryx was caught after 2 hours (31% of time running), and an injured oryx after 1 hour of walking only. Over the 3 days, persistence hunting yielded 1882-3727 kcal per man-hour, surpassing net return rates reported for hunter-gatherers and horticulturalists and net energy equivalent to the daily needs of 50 active individuals. Daily energy expenditure (5024 kcal day^-1) and water turnover (11.4 l day^-1) were high but within ranges reported for subsistence populations in hot climates. Water loss remained below the critical dehydration threshold. Despite high air (36-41 °C) and ground (43-60 °C) temperatures, the hunter maintained a safe core temperature (≤39 °C), while the oryx reached hyperthermic levels (44 °C). These findings suggest that persistence hunting in arid environments is energetically viable and thermally manageable, even for unacclimatized individuals. The relatively low proportion of running-and its complete absence when pursuing disadvantaged prey-supports the potential feasibility of persistence hunting even among hominins without advanced endurance running adaptations.