Quantifying heterogeneity of hominin environments in and out of Africa using herbivore dental traits

Abstract

Our own species, Homo sapiens, has been able to invade near-all global ecosystems through a unique form of ecological plasticity. To understand how Homo sapiens have been able to disperse to such a wide range of environments, we need to understand the origins of the characteristic which enabled this, plasticity. Growing evidence indicates that Homo species were already able to occupy a diverse set of environments in the Early Pleistocene, suggesting that the origins of human ecological plasticity have deeper roots than previously anticipated. We analysed the distribution of two dental traits, mean ordinated hypsodonty of large herbivores and proboscidean mesowear, across the mammalian communities at Early Pleistocene hominin sites, to infer the vegetation and climate contexts of these locations. The global distribution of community-level dental traits suggests that, while open grassy vegetation made up a large proportion of the sites, mixed and wooded vegetation was also represented. From our analysis we conclude that Early Pleistocene Homo species were able to exploit habitats with different vegetation types and occupied a range of different environments. In addition to this we found that the distribution of dental traits of mammalian communities in the Eurasian sample was notably different from that of the African sample, suggesting that Homo's dispersal into Eurasia resulted in a niche expansion. Together these findings suggest that Homo in the Early Pleistocene was ecologically plastic and occupied a wide environmental niche space.