Effect of resource spatial correlation and Hunter-Fisher-Gatherer mobility on social cooperation in Tierra del Fuego

This article presents an agent-based model designed to explore the development of cooperation in hunter-fisher-gatherer societies that face a dilemma of sharing an unpredictable resource that is randomly distributed in space. The model is a stylised abstraction of the Yamana society, which inhabited the channels and islands of the southernmost part of Tierra del Fuego (Argentina-Chile). According to ethnographic sources, the Yamana developed cooperative behaviour supported by an indirect reciprocity mechanism: whenever someone found an extraordinary confluence of resources, such as a beached whale, they would use smoke signals to announce their find, bringing people together to share food and exchange different types of social capital. The model provides insight on how the spatial concentration of beachings and agents’ movements in the space can influence cooperation. We conclude that the emergence of informal and dynamic communities that operate as a vigilance network preserves cooperation and makes defection very costly.MICINN http://www.idi.mineco.gob.es/ CSD2010-00034 (SimulPast CONSOLIDER-INGENIO 2010) and HAR2009-06996; the government of Castilla y Leónhttp://www.jcyl.es/ GREX251-2009; the Argentine CONICET http://www.conicet.gov.ar/PIP-0706; and the Wenner-Gren Foundation for Anthropological Researchhttp://www.wennergren.org/ "Social Aggregation: A Yamana Society's Short Term Episode to Analyse Social Interaction, Tierra del Fuego, Argentina". The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscrip

Temporomandibular joint osteoarthritis in human ancient skeletal remains from Late Holocene in southern Patagonia

Low prevalence of caries, high stages of dental attrition (DA), and moderate frequency of antemortem tooth loss (AMTL) were found in skeletal remains of hunter-gatherers from southern Patagonia. However, osteoarthritis (OA) of temporomandibular joint (TMJ), possible related to oral health, has not been studied so far. The influence of hunter-gatherer living conditions on the development of TMJ-OA was scarcely evaluated, and analyses of degenerative changes of TMJ in nonindustrialized groups are needed. The aim of this study is to analyse the association between degenerative changes of TMJ, oral disease, and palaeodietary patterns in skeletal remains of hunter-gatherers from southern Patagonia. Degenerative changes of TMJ were recorded in 25 adult skulls of both sexes. Eburnation of articular eminence and/or mandibular condyle was considered as pathognomonic of OA. In the absence of eburnation, OA was diagnosed when two or more of the following lesions were identified: (a) new bone formation on joint surface, (b) new bone formation of joint margins, (c) porosity on the joint surface, and (d) modification of joint contour. In the studied skeletons, it was found that OA prevalence is 28%, similar to those observed in other hunter-gatherer populations elsewhere. TMJ-OA is mostly related to AMTL and older age, but no relation was found with caries and DA, sex, region, dietary patterns, and chronology. However, consumption of terrestrial resources in the diet cannot be discarded as a related factor. Further studies are necessary to explore the morphological variability of the mandible and its possible relationship with different diets and dental pathologies in these populations.Fil: Suby, Jorge Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; ArgentinaFil: Giberto, Diego Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin