Doctoral Dissertation Improvement Award: Determining Season Of Death By Dental Microwear Analysis

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

The evolution of meat eating in the hominin (ancestral human) diet is central to hypotheses about the emergence of the genus Homo, the development of the modern body plan, the elongation of lifespan, and the hominin expansion from Africa into Eurasia and beyond. Seasonal resource fluctuation can have a profound effect on adaptive developments such as these, and indeed, it is during the increased aridity and seasonality of the Early Pleistocene (2.588 - 0.781 million years ago [Ma]) that the earliest evidence for hominin meat-eating appears. However, little is known about the seasonal dynamics of hominin foraging at this time. This study provides a timely insight into the successful strategies of early Homo during an extended period of climate change and variability by examining the timing of meat foraging at Olduvai Gorge, Tanzania. Though meat had the potential to increase energy budgets seasonally or annually, it also placed hominins in competition with both predators and scavengers. Technological and behavioral evidence for butchery at Olduvai suggests that despite the dangers, meat was an increasingly valuable resource in the context of expanding savannas and receding forests. In addition to covering this critical time in hominin evolution, Olduvai is well-suited for the project because it is among the best-studied localities dating to 1.9 - 1.2 million years ago, and is at the center of debates about hominin meat foraging and landscape use. Research there will contribute to the long tradition of international and local collaboration, providing valuable ongoing training to the future paleoanthropologists and conservationists who will safeguard our cultural heritage. The project will also further the training of Alia Gurtov, a graduate student at the University of Wisconsin and will provide data for her doctoral dissertation. By examining the timing of hominin foraging at Olduvai, this research can elucidate the significance of meat as a resource in times of low precipitation and relative resource scarcity, and the strategies that elevated hominins to compete at a new trophic level. It will do so using dental microwear texture analysis (DMTA) on fossil bovid prey. DMTA is a non-destructive technique that uses scale sensitive fractal analysis to examine microscopic abrasions reflecting the fracture properties of an organism's diet in the previous weeks or days. Pilot research has demonstrated that DMTA is capable of distinguishing between assemblages of impala (Aepyceros melampus) hunted by Hadza hunter-gatherers in the wet and dry seasons. As a browser-grazer, impala are an appropriate modern analog for several common prey species at Olduvai. Though DMTA cannot identify the season of death for individuals, it can be used comparatively. The anthropogenic assemblage FLK Zinj is penecontemporaneous with the carnivore-generated assemblage of FLK North, located 200 meters away. This study will use the modern impala analog to ascertain which season is best represented at each locality and compare the results to see if hominins and carnivores were operating during the same times of the year in the same environments. This research will begin to determine if Early Pleistocene hominin meat-acquisition varied seasonally, and if the strategy invited or avoided confrontation with carnivores, thereby contributing to our knowledge of Pleistocene hominin foraging adaptations.