by Curtis W. Marean, School of Human Evolution and Social Change at the Institute of Human Origins at Arizona State University
At some point between 195,000 and 123,000 years ago, the population size of Homo sapiens plummeted, thanks to cold, dry climate conditions that left much of our ancestors' African homeland uninhabitable. Everyone alive today is descended from a group of people from a single region who survived this catastrophe.
The southern coast of Africa would have been one of the few spots where humans could survive during this climate crisis, because it harbors an abundance of shellfish and edible plants.
Excavations of a series of sites in this region have recovered items left behind by what may have been that progenitor population.
The discoveries confirm the idea that advanced cognitive abilities evolved earlier than previously thought—and may have played a key role in the survival of the species during tough times.