Exploring the diet of ancient mammals

Zinc isotope analysis of fossil mammalian teeth could represent a viable approach for reconstructing past food webs, a study suggests. One technique for dietary reconstruction involves the analysis of stable isotopes of elements such as nitrogen found in collagen from bone and teeth. However, collagen degrades over time, so this well-established method cannot be successfully applied in tropical environments to mammals older than approximately 15,000 years. Because zinc is incorporated into tooth enamel and might be better preserved over long time periods than collagen-bound nitrogen, Nicolas Bourgon and colleagues attempted to reconstruct past food webs by examining the 66Zn/64Zn ratio (i.e., the δ66Zn value) in fossil tooth enamel dated to the Late Pleistocene, around 38,400–13,500 years ago. The samples, recovered from a subtropical cave, were obtained from 72 diverse specimens belonging to 22 mammalian taxa. The authors report that δ66Zn values were lowest for carnivores, intermediate for omnivores, and highest for herbivores, with almost no overlap between carnivores and herbivores. Moreover, zinc concentration distribution was similar in cross-sections of six fossil mammalian teeth and three modern mammalian teeth, suggesting that δ66Zn values remain in pristine condition over long timescales in a subtropical setting. The results suggest that zinc isotope analysis could serve as an archeological and paleontological tool for assessing the diet of ancient mammals, according to the authors.

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Article #19-11744: “Zinc isotopes in Late Pleistocene fossil teeth from a Southeast Asian cave setting preserve paleodietary information,” by Nicolas Bourgon et al.

MEDIA CONTACT: Nicolas Bourgon, Max Planck Institute for Evolutionary Anthropology, Leipzig, GERMANY; tel: 0049 (0) 341 3550 364; e-mail: <

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