Scholars reconstruct the prehistoric population movements that ultimately distributed the human species around the planet from three sources of evidence: fossil specimens, archaeological remains, and DNA. While all three diverge in their details, they generally agree that an ancestral species, Homo erectus, migrated into Eurasia about 1.6 million years ago, and our own species, Homo sapiens, emerged in Africa around 300,000 years ago and had left it by 100,000 years ago.1 H. sapiens reached Australia by 65,000 years ago, Europe by 45,000 years ago, and the Americas by 15,000 years ago.2