Axial skeletal bone grease rendering in guanacos: Implications for the zooarchaeological record of Patagonia and Tierra del Fuego (Argentina)

Abstract

The objective of this study is to evaluate bone grease yield in different anatomical units from the axial skeleton of a guanaco (Lama guanicoe). Levels of fragmentation resulted from bone grease rendering activities are also analysed. Elements from axial region have generally low representation in archaeological contexts of Patagonia and Tierra del Fuego, so new frames of reference to study this bias are provided. Axial bones yield 157.2 g of bone grease after five hours of boiling, and most of it was obtained during the first hour. The lumbar provides the highest amount of bone grease, followed by the pelvis, ribs, thoracic, sternum, cervical, and sacrum. Elements with the highest content of lipids (pelvis, lumbar, and ribs) also present the highest fragmentation indexes. In turn, denser bones have greater rates of fragmentation than less dense ones. This experimental study raises the importance of the axial region as a significant source of lipids for the human diet in the past, both for immediate and delayed consumption. Bone grease rendering generates a significant degree of bone fragmentation, which reduces specimen’s anatomical identifiability and advises us about the difficulty of assessing the formational process of bone assemblages. Nevertheless, taking it into account as an additional variable in faunal analyses may provide answers to the general pattern recorded in the archaeological sites of Patagonia and Tierra del Fuego.