After successfully colonizing the world about 50,000 years ago, ancient humans spent 20,000 years learning to survive in Africa’s most challenging habitats, from dense rainforests to coking deserts.
This eco-boot boot camp could explain why earlier humans failed to migrate from Africa, while later people thrive globally.
New research published in nature shows that human ancestors have greatly expanded their environment since about 70,000 years ago, thus developing survival skills in various African ecosystems, which is crucial to conquering the new continent.
Huge ecological expansion
“We formed a dataset of archaeological sites and environmental information covering the last ten million years in Africa,” said Dr. Emily Hallett, Ph.D., of Loyola University, Chicago, a co-leader of the study. Her team analyzed archaeological sites on 479 radioactive dates to track how human habitat preferences change over time.
The results surprised the researchers. Instead of staying in the familiar savanna environment, humans began to venture into the territory they had avoided before. They moved into dense forests in the west and central Africa, where thick canopies clogged the sun and navigation proved dangerous. At the same time, they entered North Africa’s harsh Sahara and semi-arid Sahel.
Dr Michela Leonardi of the Natural History Museum in London added: “Our results show that the human niche is beginning to expand significantly from 70 millennia, and that this expansion is driven by the increased use of humans for a variety of habitat types, from forests to arid deserts.”
Why earlier migration failed
Previous human scattered outside Africa occurred in favorable climate windows when rainfall increased in the Saharo-Arabian desert belt created a “green corridor”. These migrations have no genetic marks in modern populations, suggesting that they ultimately failed.
Successful migration about 50,000 years ago occurred under more challenging conditions. Andrea Manica of Cambridge University explained: “About 70,000-50,000 years ago, the easiest route in Africa was more challenging than in previous periods, but this expansion was huge and ultimately successful.”
What made a difference? Research shows that humans have developed unprecedented ecological flexibility through African training grounds.
The climate is unstable as a teacher
The period from 70,000 to 50,000 years ago was climate turbulent. Heinrich Event 6 brings cooler, drier conditions, while the repeated shifting between wet and wet spells challenges human adaptability. This instability does not immediately drive people out of Africa, but rather forces innovation in survival strategies.
During this period, archaeological evidence suggests that humans have developed new technologies and behaviors: innovation in innovation in water storage and expanded dietary scope. These are not isolated inventions, but part of a broader model of environmental mastery.
The statistical model of the study shows that humans increasingly occupy the annual temperature range and learn to survive in areas with sparse vegetation, which is a skilled worker that will be invaluable when encountering various landscapes in Eurasia.
Mainland Laboratory
Africa is essentially a human ecological adaptation laboratory. From the equatorial rainforest to the most severe deserts on Earth, the continent’s extreme diversity provides the perfect training ground for developing an ideal training ground for survival techniques that are applicable worldwide.
“Unlike previous humans dispersed Africa, the human population that moved into Eurasia about 60-50 thousand years ago has unique ecological flexibility due to the habitat that addresses climate challenges,” said Professor Eleanor Scerri of Max Planck.
This flexibility does not necessarily mean a larger population. Due to the low load-bearing capacity, desert areas cannot maintain many people. Instead, expansion shows that humans become highly mobile, moving between different habitats and increasing contact between the two groups.
Today’s humans are unparalleled. Humans can trace the 20,000-year ecological experiments from the Arctic tundra to tropical jungles. This study provides new evidence that the global dominance of our species does not begin with a single breakthrough, but is a step-by-step grasp of the various challenges of our continent.
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