Modeling Subsistence and Mobility of Homo erectus in Sangiran

Christine Hertler1,2*, Jan-Olaf Reschke1,3, Ana Belén Galan Lopez3, Iwan Pramesti Anwar4, Mika Rizki Puspaningrum4, and Angela A. Bruch1,2

The UNESCO World Heritage site Sangiran has been studied for almost a century. The locality is unique in providing a long sequence documenting the arrival of hominins in insular Southeast Asia and further steps in hominin evolution. A rich archaeological and fossil record allows for interpretations of ecology and environment. However, fossil hominins are mainly retrieved from coastal and/or fluvial deposits which are hardly informative regarding subsistence strategies, as such deposits do not preserve functional contexts due to taphonomic reasons. In this study, we take advantage of paleoenvironmental reconstructions and apply them to simulate the subsistence behaviour of Homo erectus. The ForeGatherer ABM allows to examine subsistence and mobility behaviour under a set of dietary regimes. Ethnographic comparisons show that distribution, frequency, and accessibility of food resources are main drivers for foraging-related mobility behaviour. The model uses reconstructed monthly net-primary productivity to derive the availability of edible plants and reconstructed animal populations to assess the occurrence of potential prey. Foragers adjust their mobility patterns to cover their energetic needs, generally following a central-place foraging approach. We use the model to examine return rates, annual home ranges covered, as well as length and duration of foraging trips. The monitoring variables reflect annual dynamics which follow a seasonally changing resource distribution. In this contribution we will introduce the ForeGatherer ABM, discuss monitoring variables, as well as conclusions regarding population dynamics.