More than 240 million people in sub-Saharan Africa today speak one of the more than 500 Bantu languages. Now a study shows that their ancestors spread from the place of origin of these populations in West Africa much earlier than thought. Around 4,400 years ago, these Bantu ancestors themselves crossed the dense jungle of Central Africa, although this was previously considered impossible or at least very unlikely due to their traditional way of life.
Originally, the ancestors of the Bantu-speaking populations only lived in a small area of West Africa, near what is now the Nigeria-Cameroon border. However, Bantu-speaking cultures now occupy more than nine million square kilometers of sub-Saharan Africa and shape the linguistic, economic and cultural landscape of many African countries. This enormous expansion of Bantu-speaking people therefore represented a profound upheaval in African cultural history.
When did the Bantu begin to expand?
However, until now it has been disputed when this Bantu expansion took place and via which routes. Because unlike many hunter-gatherer peoples, the early Bantu were already sedentary farmers for whom the vast Central African rain forest represented an unsuitable habitat. “It was thought that the dense rainforest would have made it very difficult to transport and care for the agricultural products and livestock characteristic of the Bantu expansion,” explains co-author Damián Blasi from the Max Planck Institute for Evolutionary Anthropology in Leipzig. In addition, the Bantu mainly cultivated dry-adapted crops such as crabgrass, pearl millet and cowpea, which would not thrive in the humid rainforest climate.
This is one of the reasons why many scientists previously assumed that the Ur-Bantu only migrated south in the course of a climate change around 3000 to 2500 years ago. At that time, the climate became drier and a savanna zone around 400 kilometers wide connected the northern and southern edges of the rainforest belt. The early Bantu could therefore have moved through this corridor without having to traverse dense rainforest. However, there are also hypotheses according to which the Bantu expansion must have started before this time. To provide more clarity, Blasi, first author Ezequiel Koile from the MPI for Evolutionary Anthropology and their colleagues used a new method to reconstruct the Bantu expansion.
Bantu language family tree suggests early migration
For their study, the research team analyzed linguistic data on more than 400 Bantu and other closely related languages. Using novel computational methods, they mapped similarities and differences between the various Bantu languages, much like geneticists study mutations in different genomes. This enabled the team to reconstruct the geographical and temporal family tree of the Bantu languages, and thus determine when which Bantu peoples appeared in different regions. “It’s really exciting that we’ve now managed to use these new methods to produce the most comprehensive analysis of the Bantu languages to date,” says Koile’s colleague Simon Greenhill. “They enable us to bring clarity to long-standing debates about the major dispersal events of human populations.”
The analyzes revealed: The spread of early Bantu-speaking people from their area of origin began much earlier than is generally assumed. They must have migrated south from the Gulf of Guinea more than 4000 years ago – long before the savannah corridor through the dense rainforest opened up. “This supports the growing evidence that tropical rainforests may not necessarily be a barrier to the spread of farming populations,” the scientists explain. They suspect that the early Bantu adapted to a certain extent to their new environment during their expansion phase and changed their way of life at least in part. In her view, this could also apply to other migration movements of early peasant cultures. “Of course, ecology plays a big role, but it is not fate-determining,” says co-author Russell Gray from the MPI for Evolutionary Anthropology.
Source: Max Planck Society; Specialist article: Proceedings of the National Academy of Sciences, doi: 10.1073/pnas.2112853119