Wear Improvement of Tools in the Cold Forging Process for Long Hex Flange Nuts.
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ABSTRACT:
SUBMITTER: Hsia SY
PROVIDER: S-EPMC5455396 | biostudies-other | 2015 Sep
REPOSITORIES: biostudies-other
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Project description:Burmese long-tailed macaques (Macaca fascicularis aurea) are one of a limited number of wild animal species to use stone tools, with their tool use focused on pounding shelled marine invertebrates foraged from intertidal habitats. These monkeys exhibit two main styles of tool use: axe hammering of oysters, and pound hammering of unattached encased foods. In this study, we examined macroscopic use-wear patterns on a sample of 60 wild macaque stone tools from Piak Nam Yai Island, Thailand, that had been collected following behavioural observation, in order to (i) quantify the wear patterns in terms of the types and distribution of use-damage on the stones, and (ii) develop a Use-Action Index (UAI) to differentiate axe hammers from pound hammers by wear patterns alone. We used the intensity of crushing damage on differing surface zones of the stones, as well as stone weight, to produce a UAI that had 92% concordance when compared to how the stones had been used by macaques, as observed independently prior to collection. Our study is the first to demonstrate that quantitative archaeological use-wear techniques can accurately reconstruct the behavioural histories of non-human primate stone tools.
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Project description:Riverine populations are typical of the Amazon region that depend on nature for subsistence. These people are considered an intermediate population between the urban and indigenous, the original Amazon habitants. The aim of this cross-sectional study was to evaluate the relationship between tooth wear and age in a remote riverine population from the Amazon, located by the Tucumanduba River (n = 94), and to compare them to previous findings obtained from semi-isolated indigenous (n = 223) and urban populations (n = 40) from the Amazon region, which were examined using the same methodology. Using linear regression, tooth wear explained 54.5% of the variation in the ages of the riverine subjects (p<0.001). This coefficient is mid-way between those obtained in semi-isolated indigenous populations (65-86%) and urban subjects (12%) living in the Amazon. Our findings suggest that tooth wear, a direct evidence of what an individual ate in the past, may be an indicator of the acculturation process in remote populations.
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