Before the migration known as 'Out of Africa,' early human populations adapted to various challenging habitats across Africa, including forests and deserts. This adaptation was crucial for their eventual spread across the world.
Current evidence indicates that all non-Africans are descendants of a small group that migrated into Eurasia approximately 50,000 years ago. However, prior attempts at dispersal left no lasting impact on present-day populations.
A new study published in Nature reveals that around 70,000 years ago, early humans began utilizing diverse African habitats more extensively than before. They inhabited equatorial forests in West and Central Africa and desert regions in North Africa, adapting to new environmental conditions.
This adaptability may have been enhanced by social developments like long-distance networks facilitating cultural exchange. As humans occupied more of Africa, previously isolated regions connected, promoting further adaptability. Consequently, our species became adept at surviving in varied environments.
Professor Andrea Manica from the University of Cambridge stated: “Around 70,000-50,000 years ago, the easiest route out of Africa would have been more challenging than during previous periods, and yet this expansion was big - and ultimately successful.”
Dr. Emily Hallett from Loyola University Chicago explained: “We assembled a dataset of archaeological sites and environmental information covering the last 120,000 years in Africa. We used methods developed in ecology to understand changes in human environmental niches - the habitats humans can use and thrive in - during this time.”
Dr. Michela Leonardi added: “Our results showed that the human niche began to expand significantly from 70,000 years ago, and that this expansion was driven by humans increasing their use of diverse habitat types, from forests to arid deserts.”
Professor Eleanor Scerri noted: “Unlike previous humans dispersing out of Africa, those human groups moving into Eurasia after around 60-50,000 years ago were equipped with a distinctive ecological flexibility as a result of coping with climatically challenging habitats.”
Previous unsuccessful dispersals occurred during favorable climatic conditions creating 'green corridors' through which people moved into Eurasia. The flexibility developed around 70,000 years ago allowed modern humans to adapt successfully to diverse environments globally.
The research received support from organizations including the Max Planck Society and European Research Council.
Reference: Hallett et al., "Major expansion in the human niche preceded out of Africa dispersal," Nature (June 2025).