Ken Chiacchia writes: Curtis Marean of Arizona State University, leader of an international team studying early human settlements in the Cape Floral region of South Africa, is triangulating what may have been humanity's closest brush with extinction using three avenues of research. The team's archeological digs have demonstrated human habitation and life-sustaining protein and carbohydrate food sources at a point in the last glacial maximum when virtually no evidence of humans can be found elsewhere in Africa. DNA evidence points to a roughly contemporaneous genetic bottleneck in which the population crashed to 15,000 or fewer individuals. And new climate simulations of the area using Pittsburgh Supercomputing Center's Blacklight supercomputer for the first time provide enough detail to show the area was likely to be an island of moderate climate at a time when the rest of Africa was too arid to support human life. Interestingly, humans began to display modern behavior such as heat-treating stones for tools and artistic representations during this period.