Scientists have pieced together a migration that changed Africa
Bantu peoples conquered the dense rainforest 4,400 years ago to spread their languages and culture across the continent, according to scientists from the University of Auckland and Germany’s Max Planck Institute for Evolutionary Anthropology.
Migration has transformed the languages, economy and culture of sub-Saharan Africa, with hundreds of millions of people today speaking Bantu languages.
New computational methods and linguistic data have helped researchers piece together what happened.
“State-of-the-art computer analysis of languages allowed us to test scenarios to determine when and how Bantu-speaking people spread across the continent,” says Dr Simon Greenhill, from the School of Biological Sciences at University of Auckland.
The ancestors of the current Bantu speakers lived 5,000 to 6,000 years ago near the current border of Nigeria and Cameroon in West Central Africa.
The puzzle: how and when did these peoples expand to eventually cover about half of the African continent despite the vast barrier of Central African rainforest, which stretched from the Atlantic coast to the Great Lakes of East Africa.
Linguistic data from over 400 Bantu and closely related languages produced a language family tree to reconstruct the southward spread of Bantu speakers.
It was previously thought that as farmers with livestock and crops such as millet, Bantu peoples would have found it difficult, if not impossible, to traverse the rainforest. This has fueled speculation that their route may have passed through the Sangha River Gap, a savannah corridor that opened up along the rainforest about 2,500 years ago.
However, the new study rejects this notion, showing that the migration moved through the rainforest, possibly with people adopting subsistence lifestyles instead of relying on intensive agriculture.
“The potential consequences of our findings extend well beyond Bantu-affiliated migrations, as they challenge the idea that agricultural expansions are entirely determined by ecological conditions assumed for the cultivation and exploitation of specific crops. “, write the scientists in an article published in the journal PNAS.
The results match recent anthropological evidence of human adaptation to tropical forests.
“Of course, ecology matters, but it’s not fate,” says Professor Russell Gray, who is the study’s lead author. He is based in Germany with the Max Planck Institute and affiliated with the School of Psychology at the University of Auckland.
The researchers used a new method borrowed from genetics called non-sequence sampling to account for possible geographic biases caused by a lack of data for about 200 undocumented Bantu languages.
“It’s really exciting to be able to use these methods to provide the most comprehensive analysis of Bantu languages to date,” says Dr Greenhill. “These methods give us real power to resolve these longstanding debates about major human population expansion.”
In addition to the non-sequenced sampling approach, an important methodological improvement was the use of a “breakthrough” geographic model.
“According to this model, with each split in the language tree, one of the populations remains in the same place, while the other migrates”, explains Dr. Remco Bouckaert, principal investigator at the School of Computer Science of the University of Auckland. . “It seems more realistic than other diffusion-based methods, where both populations are forced to migrate.”
The study’s lead author was Dr. Ezequiel Koile of the Max Planck Institute for Evolutionary Anthropology.
© Scoop Media