The origins of agriculture was one of the most significant turning points in human history, yet, no consensus has been reached on its causes. The most commonly cited precursors to agriculture include population pressure, intensive foraging, and sedentism. These critical factors play central roles in models of agricultural origins, yet have not been rigorously tested. In the Levant, the Natufian period (ca. 13,000-10,500 B.P.) immediately preceded agricultural origins. This research applies ecological models to the Natufian archaeological record to formally test whether population pressure, sedentism, and intensified resource use were major catalysts for economic change at the transition to agriculture. It reconstructs predator-prey relationships by recording the potential effects of human hunting on prey populations and examining how these effects change with varying degrees of hunting pressure. The effects of human hunting on prey populations is governed by the ecological characteristics of prey species. Prey species vary in their cost of capture and their resistance to hunting pressure. The presence of some species and not others at archaeological sites may thus reflect changes in human population density. In archaeofaunal assemblages these changes are expressed in the relative abundance and age structures of prey species. The prey composition and prey age profiles from four Natufian sites---Hayonim Cave, Hayonim Terrace, Hilazon Tachtit, and el-Wad Cave---support three major conclusions. First, site occupation intensity reached unprecedented levels in the Early Natufian in comparison to earlier Paleolithic periods in the region. Second, a substantial decrease in site occupation intensity back to virtually pre-Natufian conditions occurred during the Late Natufian in association with the Younger Dryas climatic event. Finally, the Natufians exerted constant, intensive pressure on their resources throughout the duration of the period. These trends have implications for human demography at the regional scale. During the Early Natufian period, human population densities in the Mediterranean zone peaked for the Paleolithic period. With the decline in site occupation intensity in the Late Natufian, human populations became more mobile and partial depopulation of the region occurred. The origins of agriculture thus emerged from a atmosphere of long-term resource stress, not as an immediate response to environmental deterioration in the Late Natufian phase.(Revue)