Ancient humans spent 20,000 years mastering survival in Africa's most challenging environments—from dense rainforests to scorching deserts—before successfully spreading across the globe around 50,000 years ago, according to new research published today.
This ecological training may explain why earlier human migrations out of Africa failed while later ones conquered new continents. The study, published in Nature, reveals that human ancestors dramatically expanded their environmental range starting around 70,000 years ago, developing survival skills across diverse African ecosystems that proved crucial for global colonization.
Researchers analyzed 479 archaeological sites spanning 120,000 years across Africa to track how human habitat preferences evolved over time. Rather than staying in familiar savanna environments, humans began venturing into previously avoided territories around 70,000 years ago1.
"Our results showed that the human niche began to expand from 70 thousand years ago, and that this expansion was driven by humans increasing their use of diverse habitat types, from forests to arid deserts," says Dr. Michela Leonardi of London's Natural History Museum1.
The findings build on research published in January showing that even earlier human ancestors possessed remarkable adaptability. Studies published in Communications Earth & Environment revealed that Homo erectus thrived in extreme desert conditions in East Africa at least 1.2 million years ago, challenging assumptions that only modern humans could survive such environments234.
At Tanzania's Oldupai Gorge, researchers found evidence that Homo erectus repeatedly returned to the same locations near water sources over thousands of years, developing specialized stone tools for survival in semi-desert conditions12.
"By doing archeology, what we can see is that Homo erectus keeps coming back to the same place in the landscape over thousands of years," says University of Calgary professor Dr. Julio Mercader, lead author of the January study2.
The research contradicts previous hypotheses that only Homo sapiens could adapt to extreme ecosystems, suggesting Homo erectus was a generalist species capable of surviving across varied landscapes1.
Unlike previous humans dispersing out of Africa, those moving into Eurasia after 60,000 to 50,000 years ago were equipped with distinctive ecological flexibility from coping with climatically challenging habitats, according to Prof. Eleanor Scerri of the Max Planck Institute of Geoanthropology1.
This flexibility didn't necessarily mean larger populations but indicated humans became highly mobile, moving between different habitats and increasing contact between groups. Today's human ability to thrive everywhere from Arctic tundra to tropical jungles traces back to this period of ecological experimentation in Africa1.
