Abstract
The people of three primeval cultures lived naked or nearly naked in regions where they experienced air temperatures of ± 5 degrees Celsius during cold seasons. These were the Australian Aboriginal peoples, the Bushmen of southern Africa, and the Yamana and the Alakaluf of Tierra del Fuego. Recent meta-analyses of data on human metabolic rate and metabolic endurance enable a quantitative demonstration of feasibility: Thermoregulation at winter air temperatures while naked was feasible in the three cultures for significantly longer than 50-180 days per year (sufficient for the duration of winter). Considering the life histories of the people, their estimated, time-averaged daily (24 hours) metabolic rates in winter were 2.6 times basal-similar to the highest daily rates empirically measured in extant peoples. Although the primeval peoples' way of life was metabolically expensive, it was as feasible as the lifestyles of peoples in today's world who live at the upper bound of the metabolically possible.