Evidence Suggests Modern Humans First Left Africa at Least 100,000 Years Ago — But This Is Why That Initial Migration Failed

One of the most widely accepted theories about modern humans’ origin is the Out of Africa hypothesis. It states that Homo sapiens evolved from Africa, and then about 50,000 to 70,000 years ago, migrated to the rest of the world, outcompeting earlier hominins like Neanderthals and Denisovans.

However, there is fossil and archaeological evidence that shows earlier migration of Homo sapiens occurred before that, at least 100,000 years ago. But, these initial migrations clearly failed as none of these humans have left any descendants and were not able to survive and thrive after moving out. Let’s find out who they are, why they failed, and how the humans who migrated after that succeeded.

Evidence for Early Migrations and Their Collapse

Fossil sites at Qafzeh and Skhul in the Levant include at least 11 modern human remains, which are dated between 90,000 to more than 100,000 years. These humans did not leave any descendants that could be observed in modern times in the region.

Scientists found that they were already using stone tools, but their settlements disappeared without any trace. Additional findings, from southern Arabia (Jebel Faya) and southern China (Fuyan Cave), also point to modern humans coming out of Africa, and venturing far east, estimated to be about 100,000–125,000 years ago.

But even these groups did not last long and were not able to build their own civilization. Their migration was short-lived and often considered unsuccessful.

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Ecological Limitation: Humans’ Early Niche Was Too Narrow

Homo Sapiens Dispersals Out of Africa

A groundbreaking study analyzing 120,000 years of African archaeology found that early humans only began to diversify their ecological niche about 70,000 years ago. In other words, before this time, most human beings only lived in known and familiar areas like open savannas and woodlands.

They did not live in deserts, mountainous regions, or rainforests, which means that they do not possess the adaptability needed to survive various climates and environments. This is most likely the most significant reason why early humans were not successful at their first attempt at migration to the rest of the world.

What Changed by 50,000–70,000 Years Ago

So, what changed during the 50,000 to 70,000 years ago, compared to 100,000 years ago and more? Why did humans begin to succeed at moving out of Africa only after this time? It is because Homo sapiens who migrated out 70,000 years ago or later have already adapted to different types of environments.

They ventured not out of Africa, but in different parts of this continent, from dense forests to desert lands. They have first developed more advanced tool kits, dietary adaptations, and even cultural behaviors. These technologies and changes allowed this group of early humans to migrate successfully out of Africa and disperse all around the globe around 60,000 years ago.

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Why the Early Waves Did Not Persist

So, what exactly did the first batch of humans who moved out of Africa face that made their lineage not persist, and ultimately fail at survival? There are two most likely reasons, as the first one was discussed above, which simply states that they are not prepared or adapted in any way to be able to conquer their new environments, compete with other hominin populations like Neanderthals, and create a thriving civilization.

The other is attributed to the changes in ecological factors, such as a temporary “green corridor” which allowed migrations at first, but was suddenly cut off. This results in habitat fragmentation, which leads to genetic diversity loss and ultimately, population decline.

When there aren’t enough genetic differences in a generation of humans, they will be more prone to diseases, unable to adapt and evolve to survive changes in their climate, environment, and fight off pathogens. However, unlike this initial migration, the one that occurred between 50,000 to 70,000 years ago was made up of more adapted human beings in greater numbers, which led to their success.

When Did Hominins First Leave Africa?

Author's Final Thoughts

Modern humans did leave Africa even before the great migration events; however, those who left earlier failed and were not able to propagate and outcompete the other existing hominins in the new environments. It was only when Homo sapiens developed ecological flexibility, around 70,000 years ago, that they were able to disperse globally and conquer the world, leading to where we are today.

Read next: Recent Study Reveals Neanderthals Were Processing Bones for Fat 125,000 Years Ago — And This Is What That Reveals

References & Further Reading

Hershkovitz, I., et al. (2018). The earliest modern humans outside Africa. Science. https://doi.org/10.1126/science.aap8369

Groucutt, H. S., et al. (2018). Homo sapiens in Arabia by 85,000 years ago. Nature Ecology & Evolution. https://doi.org/10.1038/s41559-018-0518-2

Beyin, A. (2011). Upper Pleistocene human dispersals out of Africa: A review of the current state of the debate. International Journal of Evolutionary Biology. https://pmc.ncbi.nlm.nih.gov/articles/PMC3119552/

Garcea, E. A. A. (2012). Successes and failures of human dispersals from North Africa. Quaternary International. https://doi.org/10.1016/j.quaint.2011.06.034

Nicholson, S. L., Hosfield, R., Groucutt, H. S., & Scerri, E. M. L. (2021). Beyond arrows on a map: The dynamics of Homo sapiens dispersal and occupation of Arabia during MIS 5. Journal of Anthropological Archaeology. https://doi.org/10.1016/j.jaa.2021.101269