Neandertal Energetics Revisited: Insights Into Population Dynamics and Life History Evolution.

Abstract

Paleoanthropologists are increasingly utilizing energetic models to provide insights into hominin ecology and evolution. Energy dynamics represent a key interface between an organism and its environment; how energy is extracted from limited resources and allocated to various somatic functions has consequences for survival and re-production. Within the past few years, several teams of researchers have reconstructed Neandertal energy budgets to address issues such as foraging efficiency, population density and spatial utilization, cold tolerance, and the replacement of Neandertals by modern humans. In the present paper, we systematically reexamine Neandertal energy expenditure and intake through the lens of recent developments in contemporary human biology and nu-tritional science. We estimate Neandertal energy expenditure and dietary needs by using published sex-specific body mass estimates coupled with physiological information on contemporary high-latitude populations. Com-parative data suggest that four important factors contribute to high energy requirements in Neandertals: 1) large body mass and high levels of muscularity; 2) exposure to severe cold stress; 3) consumption of high meat, high protein diets; and, 4) high levels of physical activity. Contemporary northern populations have systematically elevated basal metabolic rates (BMRs) compared to lower latitude groups, an apparent adaptation to chronic and severe cold stress. In addition, field and laboratory studies suggest high dietary protein is associated with substan-tially increased metabolic heat production. Further, activity patterns among contemporary northern populations and Neandertal post-cranial morphology suggest relatively high physical activity levels. Thus, multiple lines of evidence point to extremely high energy requirements and intakes among Neandertals. The high turnover of metabolic energy in Neandertals likely had important implications for key aspects of life history, such as physical growth rates, age at reproductive maturity, and lifespan. Consequently, a detailed exploration of Neandertal ener-getics provides insights into hominin population dynamics during the Middle to Upper Paleolithic transition.The “Energetic Studies in Hominin Evolution” Symposium, Paleoanthropology Meetings, Philadelphia, PA, 27—28 March, 2007; symposium papers guest edited by Karen Steudel-Numbers (University of Wisconsin) and Cara Wall-Scheffler (Seattle Pacific University).