An alternative scenario for the first human dispersal out of Africa

Abstract

Recent paleoanthropological evidence from the early Pleistocene site of Dmanisi in Georgia has revealed that the first hominins out of Africa were more archaic than the coeval African Homo erectus. Therefore, anatomical or cultural innovations associated with the later species cannot be invoked as a cause for the first out of Africa. More evidence suggests that these archaic hominins were forest dwellers rather than savannah inhabitants. This is in agreement with their trophic role as passive scavengers. In contrast with open-dry savannah, passive scavenging is much easier and safer in forest, were carcasses can remain untouched for up two days. Moreover, forest-adapted sabertooths could have supply hominids with more carrion than modern savannah felids. Between 1.8 and 1.6 Ma a climate crisis caused a new spread of savannah and arid zones across large parts of Africa. As a consequence, early Homo populations splitted, with some populations becoming adapted to the new ecological conditions and others following woodland areas in their regression. For these last populations Southern Caucasus could have acted as a refugium area, with dominant forest conditions, still inhabited by sabertooths and with easy access to carcasses.