Leaving Africa took more than one departure
Homo erectus walked out about 1.8 million years ago; Homo sapiens later left in pulses, with a major 70 to 50,000-year wave peopling Eurasia. We carry under ten percent archaic DNA from those meetings—and reached Polynesia only within the past two millennia.
Stone tools appear by about three million years ago near the Kenyan Rift; Shangchen in China claims artefacts at 2.12 million years. Between two and one million years ago Homo filled East and Southern Africa as Homo ergaster before Homo erectus took the Levantine corridor and Horn of Africa into Eurasia around 1.8 million years ago—possibly climate-linked. Key early sites include Riwat, Ubeidiya at 1.5 million years, and Dmanisi at about 1.81 million years. Java by 1.7 million years and Atapuerca by 1.2 million years mark further spreads; Bednarik even argues for erectus rafts across open water.
Homo sapiens speciated and dispersed inside Africa around 300,000 years ago. Recent African origin models send East African migrants along southern coasts roughly 70,000 to 50,000 years ago. Earlier Eurasian fossils complicate the timeline: Misliya Cave remains at about 194,000 to 177,000 years, and disputed Apidima fragments near 210,000 years. Expanding sapiens interbred with local archaic groups so that living people inherit below ten percent archaic ancestry in regional mixes still measurable today.
After the Last Glacial Maximum, North Eurasians entered the Americas about 20,000 years ago; Paleo-Eskimo movements reached Arctic Canada and Greenland around 4,000 years ago. Austronesian expansion peopled Polynesia within the past 2,000 years in the last great ocean wave. Migration is less a single exodus than a layered weave of exits, returns, and genetic mixes across deep time.
Source: Early human migrations
