But now a growing group of researchers is casting doubt on this story. Working in Senegal, Cameroon, Malawi and elsewhere, they are uncovering evidence that early humans spread across many more parts of Africa before going anywhere else. This work has moved the field beyond the old out-of-Africa narrative and is transforming our understanding of how multiple groups of early modern humans interbred and spread across the continent, providing a more nuanced picture of our species’ complex origins.
“It’s becoming increasingly clear that humans didn’t evolve from one population in one region of Africa,” says Eleanor Scerri, an archaeologist at the Max Planck Institute for Geoanthropology in Jena, Germany. “If we really want to understand human evolution, we need to look at the entire African continent.”
Most researchers agree that early modern humans emerged in Africa between 200,000 and 300,000 years ago. They spread to other parts of the world about 60,000 years ago. Until recently, however, most experts thought that these people populated West and Central Africa, particularly the tropical forests there, only in the past 20,000 years.
For some researchers, this story was nonsense. “People like to move around a lot,” says Sarah Tishkoff, a geneticist at the University of Pennsylvania who has spent more than two decades working to unravel Africa’s deep genetic lineage. “They had this beautiful continent, they could travel all over the place, go to different niches, with different resources.”
The reason no one has found evidence of early human settlement in West and Central Africa, Scerri and others say, is that few people had looked there. For decades, most researchers focused on low-hanging fruit — areas of the continent where fieldwork was less difficult. Because the climate is drier and cooler in East and Southern Africa and the terrain is more open, fossils are easier to find and date. Most of West and Central Africa is hot and humid, which makes bones and DNA degrade more quickly. What’s more, the region can be a challenging place to work, not only because much of it is heavily forested but also because some areas are mired in protracted, chaotic conflict.
Some research suggests that cultural biases may have played a role as well. “Most of the research has been led by people from the Global North,” says Jessica Thompson, a paleoanthropologist at Yale University. “And their perspective is, ‘Well, we want to know how people got out of Africa to where we’re from.’”
As a result of all these factors, most scholars have focused primarily on sites in southern and eastern Africa. This has contributed to the idea that early modern humans primarily inhabited these areas. Frustrated that academia was not taking their ideas seriously, a few researchers began trying to find evidence to support their views. Over the past decade or so, they have found it.
Last year, a group of scientists from Senegal, Europe and the United States reported that modern humans lived in a site on the coast of Senegal 150,000 years ago. Previous estimates put the earliest human habitation in West Africa at 30,000 years ago.
What’s more, the site was in a mangrove forest, rather than the typical grassland or sparse savannah usually associated with early human habitation. Scerri says her latest research in Senegal, which has not yet been published, could push that date back even further. “It’s clear that there were different people in different places doing different things,” she says. “And they were there for a very long time. Much longer than we realized.”
Another study, from 2022, analyzed DNA from the bones of 34 people who lived in sub-Saharan Africa between 5,000 and 18,000 years ago. Examining such ancient DNA is important because it provides a much clearer window into the structure of ancient African populations. The research showed that populations that had been relatively isolated from each other began to interact across large parts of the continent between 80,000 and 20,000 years ago. These connections stretched for thousands of kilometers, from Ethiopia, through central African forests, and into South Africa.
“People were clearly moving quite widely across Africa,” says Thompson, a co-author of the study. “They didn’t stay in these small isolated populations.”
And a paper published four years ago in Nature examined the remains of two children found in a rock shelter in Cameroon, in western Central Africa. One of the children lived 3,000 years ago, while the other lived 8,000 years ago. The researchers, from Harvard and other institutions, were able to collect DNA from the two — the first ancient human DNA ever sequenced from Central Africa. They discovered four distinct human lineages between 60,000 and 80,000 years ago, including a previously unknown lineage — what they called a “ghost population” — that likely lived in West Africa. The results provide more support for the idea that humans have been in West Africa for much longer than previously thought and add to the evidence that humanity’s roots lie in more than one region of Africa.
Experts say it’s important to note that close relatives of modern humans — Neanderthals, Homo erectus and several other species — had already spread beyond Africa into Europe and Asia, in some cases millions of years ago. But these groups contributed relatively small amounts of DNA to the modern human lineage.
Because it can be so difficult to find fossils and trace ancient DNA in many parts of Africa, scientists have had to develop innovative approaches to locate early human habitation. For example, Thompson and her colleagues studied sediments around Lake Malawi in the north of the country. Over thousands of years, the lake shrank and grew, depending on the amount of rainfall. During wetter periods, the number of trees around the lake increased significantly.
But Thompson found that during a wetter period that began 80,000 years ago (and continues today), tree cover didn’t increase nearly as much as expected. Instead, the scientists found an abundance of charcoal. Thompson says this shows that people were living in the region, perhaps in fairly large numbers, and that they were burning wood extensively, either to modify the environment for hunting, cooking, or keeping warm — or all three.
A key aspect of this new understanding is the Pan-African hypothesis: Scerri and others argue that modern humans likely evolved from the mixing of different groups from different parts of the continent. “There were a number of modern human populations living in different regions of Africa, and we evolved over time from the complex interactions between them,” Scerri says. “We’re basically a mix of a mix of a mix of a mix.”
In research published last year, population geneticist Brenna Henn of the University of California, Davis, and her colleagues examined the genomes of nearly 300 Africans from across the continent. By analyzing and comparing the genetic data, they were able to construct a model for how humans emerged on the continent over the past hundreds of thousands of years. They found that modern humans descended from at least two distinct populations that lived in different parts of the continent. She and her colleagues are now analyzing the genomes of 3,000 people, mostly Africans but also people of African descent living elsewhere, as well as Native Americans and others.
Scerri has also found evidence to support the Pan-African idea. She has shown that the Middle Stone Age culture persisted in West Africa until relatively recently, less than about 11,000 years ago. This culture, a specific way of making stone tools, disappeared much earlier in other parts of the continent, 30,000 to 50,000 years ago. This is important, she says, because it is exactly what the Pan-African theory predicts: “In this model, you would expect each region to have its own distinctive cultural trajectory, due to periods of isolation. This research shows how this was possible.”
Not everyone is convinced. Richard Klein, a paleoanthropologist at Stanford University who has spent decades studying the origins of early modern humans and migration in Africa, says, “I don’t understand the evolutionary mechanism behind” the Pan-African origins theory.
Pontus Skoglund, a population geneticist at the Francis Crick Institute in London who has worked with Scerri, says the Pan-African idea is plausible but he’s not entirely convinced. “To me, it also seems possible that a large proportion of the ancestors of modern humans are in one region,” he says. “But we don’t know.” He says there’s still “a lot of uncertainty” about who was where and when.
Scerri agrees that more research is needed. But after years of battling skepticism, she says she feels vindicated that the new perspective is catching on. “This is such an exciting area to be working on right now,” she says. “It’s really an incredible story, a story that’s unfolding before our eyes.”