Abstract:Sub-Saharan Africa has shifted from having a very low population density and no population growth in the 19 th century to an extremely high population growth today. While some political demographers have linked the continent's high population growth rate to various civil wars, we argue here that a more important cause behind contemporary conflict has been this rapid demographic shift over the past century and a half. Specifically, we show that low population densities historically contributed to poverty, communal and unequal property rights, and high levels of ethnic diversity in the pre-colonial and colonial periods. In the post-colonial era, however, these three variables have provided the opportunities, motives and collective action necessary for conflict, thereby combining with high population growth rates to produce large amounts of 'sons of the soil' conflict over land. To test this argument we examine cases of contemporary civil wars in Sudan and the Democratic Republic of Congo, where we find significant evidence supporting the theory. We then examine the counterfactual case of the Rwandan genocide, where we not only find that the genocide was not a 'sons of the soil' conflict, but that Rwanda's historically high population density played a indirect but significant role in the genocide.