Prof. Barkai: "In light of previous studies, our team proposed an original hypothesis that links the two questions: We think that large animals went extinct due to overhunting by humans, and that the change in diet and the need to hunt progressively smaller animals may have propelled the changes in humankind. In this study we tested our hypotheses in light of data from excavations in the Southern Levant covering several human species over a period of 1.5 million years." Jacob Dembitzer adds: "We considered the Southern Levant (Israel, the Palestinian Authority, Southwest Syria, Jordan, and Lebanon) to be an 'archaeological laboratory' due to the density and continuity of prehistoric findings covering such a long period of time over a relatively small area -- a unique database unavailable anywhere else in the world. Excavations, which began 150 years ago, have produced evidence for the presence of humans, beginning with Homo erectus who arrived 1.5 million years ago, through the neandertals who lived here from an unknown time until they disappeared about 45,000 years ago, to modern humans (namely, ourselves) who came from Africa in several waves, starting around 180,000 years ago."