The Savannah hypotheses: origin, reception and impact on paleoanthropology.

The reconstruction of the human past is a complex task characterized by a high level of interdisciplinarity. How do scientists from different fields reach consensus on crucial aspects of paleoanthropological research? The present paper explores this question through an historical analysis of the origin, development, and reception of the savannah hypotheses (SHs). We show that this model neglected to investigate crucial biological aspects which appeared to be irrelevant in scenarios depicting early hominins evolving in arid or semi-arid open plains. For instance, the exploitation of aquatic food resources and other aspects of hominin interaction with water were largely ignored in classical paleoanthropology. These topics became central to alternative ideas on human evolution known as aquatic hypotheses. Since the aquatic model is commonly regarded as highly controversial, its rejection led to a stigmatization of the whole spectrum of topics around water use in non-human hominoids and hominins. We argue that this bias represents a serious hindrance to a comprehensive reconstruction of the human past. Progress in this field depends on clear differentiation between hypotheses proposed to contextualize early hominin evolution in specific environmental settings and research topics which demand the investigation of all relevant facets of early hominins' interaction with complex landscapes.