Researchers in North Africa are challenging the long-held scientific opinion that East Africa is ground zero for human evolution.
The oldest known stone tools used by human ancestors are about 2.6 million years old and originate from Ethiopia. The early technology was thought to have spread from East Africa to the rest of the continent. However, new research recently published in the journal Science details how archaeologists in Algeria have uncovered new evidence of flint tools that are 2.4 million years old.
While the Algerian tools are still 200,000 years younger than those found in Ethiopia, the ages are similar. Experts doubt that the knowledge of how to make stone tools could have migrated from Ethiopia to Algeria in that time.
“The time difference is so short for an expansion of 7,000 kilometres because prehistorical migrations were really slow,” says Mohamed Sahnouni, an archaeologist at the National Research Center on Human Evolution in Spain, who led the excavation. “That’s why we think there may be more than one spot in Africa were early human culture arrived.”
In 2017, archaeologists in Morocco published their findings of a dig where they unearthed what turned out to be the oldest human remains in the world. (See a related article, “Discovery of Oldest Human Remains Fosters Moroccan Pride.”)
While these two discoveries are not directly related—with a time gap of more than two million years between them—they collectively serve to point the evolutionary compass northwards, say experts.
“They both emphasize the importance of northern Africa in human evolution, which has often been neglected in favor of East Africa,” says Ignacio de la Torre, a professor of palaeolithic archaeology at University College London who was not involved in either study.
Sahnouni agrees. “In our field, all the focus has been on East Africa because of the good condition of excavations there, but now some new things are coming out of North Africa, which is quite surprising to many people,” he says.
“Look at the earth-shattering information coming out of either Algeria or Morocco,” Sahnouni says. “It means that early human evolution didn’t happen in one place in Africa, but in at least two locations and probably in other parts of the African continent.”
Sahnouni spent eight years excavating the site, which is about a two-and-half-hour drive inland from the capital, Algiers, where he discovered several different stone tools apparently designed for chopping and cutting. They suggest a community of active hunters and butchers.
Close to the tools, Sahnouni’s team found a plethora of elephant, hyena, pig and crocodile bones with notches and indentations on them, which suggests the tool-users weren’t picky about what they butchered.
If Sahnouni is correct that 200,000 years isn’t enough time for our evolutionary ancestors to have traveled across nearly 4,500 miles of forest, mountains and desert, then that, combined with the discovery of the oldest human remains coming from Morocco, calls into question an underlying principle of what scientists thought to be humankind’s evolutionary story.
De la Torre says the common narrative needs a fresh examination. “We need to focus more on the huge potential of northern African sequences to study the early stages of human evolution,” he says.
Human ancestors could have simultaneously invented stone tools in other parts of Africa—in addition to the North and East—but it’s just that archaeologists haven’t found the artifacts yet or that they weren’t as well preserved. West Africa, for example, typically has acidic soils, which means the preservation of remains is poor.
“There are large parts of Africa still largely unexplored,” says de la Torre.
But for the time being, Sahnouni is pleased that the scientific community is coming around to the idea of an alternative evolutionary theory.
“I think North Africa has its place now in the story of the emergence of humankind and culture,” says Sahnouni.