title: Dietary options and behavior suggested by plant biomarker evidence in an early human habitat.
abstract: The availability of plants and freshwater shapes the diets and social behavior of chimpanzees, our closest living relative. However, limited evidence about the spatial relationships shared between ancestral human (hominin) remains, edible resources, refuge, and freshwater leaves the influence of local resources on our species' evolution open to debate. Exceptionally well-preserved organic geochemical fossils--biomarkers--preserved in a soil horizon resolve different plant communities at meter scales across a contiguous 25,000 m(2) archaeological land surface at Olduvai Gorge from about 2 Ma. Biomarkers reveal hominins had access to aquatic plants and protective woods in a patchwork landscape, which included a spring-fed wetland near a woodland that both were surrounded by open grassland. Numerous cut-marked animal bones are located within the wooded area, and within meters of wetland vegetation delineated by biomarkers for ferns and sedges. Taken together, plant biomarkers, clustered bone debris, and hominin remains define a clear spatial pattern that places animal butchery amid the refuge of an isolated forest patch and near freshwater with diverse edible resources.
authors.affiliation: Geological Institute, ETH Zürich, Zurich 8092, Switzerland; clayton.magill@erdw.ethz.ch.
authors.forename: Clayton R
authors.initials: CR
authors.lastname: Magill
authors.affiliation: Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08854;
authors.forename: Gail M
authors.initials: GM
authors.lastname: Ashley
authors.affiliation: Department of Prehistory, Complutense University, Madrid 28040, Spain;
authors.forename: Manuel
authors.initials: M
authors.lastname: Domínguez-Rodrigo
authors.affiliation: Department of Geosciences, The Pennsylvania State University, University Park, PA 16802.
authors.forename: Katherine H
authors.initials: KH
authors.lastname: Freeman
mesh_terms: D000473:Alkanes / Q000032:analysis; D000818:Animals; D005075:Biological Evolution; D015415:Biomarkers; D060435:Carnivory; D004032:Diet / Q000266:history*; D017753:Ecosystem; D005247:Feeding Behavior; D005523:Food Supply / Q000266:history*; D065928:Forests; D005580:Fossils; D065948:Grassland; D060434:Herbivory; D049690:History, Ancient; D015186:Hominidae / Q000523:psychology*; D006801:Humans; D006812:Humic Substances / Q000032:analysis; D008031:Lignin / Q000032:analysis; D010636:Phenols / Q000032:analysis; D063148:Plant Dispersal; D010944:Plants / Q000737:chemistry / Q000145:classification; D011235:Predatory Behavior; D055110:Radiometric Dating; D012118:Resorcinols / Q000032:analysis; D013636:Tanzania; D014070:Tooth / Q000033:anatomy & histology; D014881:Water Supply / Q000266:history; D053833:Wetlands
chemical_list: D000473:Alkanes; D015415:Biomarkers; D006812:Humic Substances; D010636:Phenols; D012118:Resorcinols; D008031:Lignin
keywords: biomarker; carbon isotope; human evolution; leaf wax; paleoecology