The application of trace metal isotope analysis to hominids: Reconstructing the behavior, diet, and physiology of wild chimpanzees
Abstract
Isotopes have been widely used by biological anthropologists to indicate migration, diet, trophic position, and habitat use in a variety of organisms. In biological anthropology, the analysis of strontium isotope ratios (87Sr/86Sr) are an established method to trace mobility and migration, whereas initial work on the stable isotope ratios of zinc (δ66Zn), iron (δ56Fe), and copper (δ65Cu) has revealed patterns related to diet, trophic position, as well as physiological differences between the sexes, respectively. These trace metals are readily analyzed in the inorganic matrix of bone and teeth, bioapatite which allows us to analyze sex-related differences in dispersal patterns, diet or trophic position, and reproductive physiology. This dissertation focuses on chimpanzees (Pan troglodytes), a large bodied and highly social non-human primate, which are genetically similar to humans, but vary drastically in life history and diet, leading to population-level differences in survivorship, fertility, and health. This makes chimpanzees a highly relevant model of the last common ancestor before our split with early humans. We employ the stable isotope ratios of trace metals (Sr, Zn, Fe, Cu) to examine dispersal, origin, age, sex, and diet in wild populations of chimpanzees. Specifically, this project establishes a reference dataset to address interspecific variation in ontogeny, reproductive biology and diet during the evolutionary transition from hominins to modern humans.