A method for constructing demographic profiles in Susscrofa using Logarithm Size Index scaling

Abstract

Demographic profiling of archaeological assemblages offers a window into the shifting exploitation strategies practiced by ancient societies. High resolution sex-specific age profiles, in particular, have yielded new insights into the evolution of early management practices taken during the initial stages of animal domestication (Zeder, 2001). This paper is the third in a series seeking to develop a method for constructing demographic profiles for Sus scrofa — one of the earliest major livestock species noteworthy for being independently domesticated in both Southwest and East Asia. The first paper in this series (Lemoine et al., 2014) presented a new system for constructing high resolution age profiles using patterns of dental eruption and wear. The second (Zeder et al., 2015) presented a new method for computing high resolution age profiles based on long bone fusion. Both papers used a reference assemblage of modern Eurasian wild boar for developing these new aging schemes, which were then applied to the large assemblage of S. scrofa remains from the Early Holocene age site of Hallan Çemi (c. 11,600 cal. BP) in southeastern Anatolia — an assemblage that previous researchers claimed provided evidence for early steps toward management (Redding, 2005). Here we focus on a subset of this modern reference collection consisting of 34 wild boar skeletons from Turkey, Iran, and Iraq. We employ a Logarithm Size Index scaling (LSI) technique to examine the effect of factors such as age, locality, and, sex on body size in modern wild boar. We find that even though both age and locality have an impact on body size, LSI values derived from select measurements of various different post-cranial elements can be used to classify individual osteological specimens as belonging to immature animals, and, for animals older than about eight months of age, as female or male. We test the reliability of these classifications by comparing the known demographic profiles of the modern reference population against those derived from the LSI classifications. Finally, we apply this new method to the Hallan Çemi assemblage and propose a method for adjusting LSI values to account for temporal size differences encountered between the modern and ancient populations. We also present methods for assessing the reliability of these classifications in the ancient population. We conclude by offering guidelines for the application of this new method to other archaeological assemblages of S. scrofa and other ungulate species that demonstrate strong degrees of sexual dimorphism.