Bantu expansion shows that habitat alters the route and pace of human dispersals

TLDR

Humans can use cultural innovations to inhabit diverse environments, raising the question of whether migrations follow familiar habitats; the Bantu expansion began roughly 5,000 years ago from West Central Africa and spread across a vast area. The study demonstrates that the Bantu expansion avoided unfamiliar rainforest habitats by following savannah corridors emerging from the Congo rainforest, likely due to climate change. The expansion avoided rainforest habitats by following savannah corridors from the Congo, likely due to climate change, and when Bantu speakers entered the rainforest, migration rates lagged by about 300 years compared with savannah movements, illustrating that unfamiliar habitats alter the route and pace of dispersals.

Abstract

Significance Humans are uniquely capable of using cultural innovations to occupy a range of environments, raising the intriguing question of whether historical human migrations have followed familiar habitats or moved relatively independently of them. Beginning ∼5,000 y ago, savannah-dwelling populations of Bantu-speaking peoples swept out of West Central Africa, eventually occupying a vast geographical area. We show that this expansion avoided unfamiliar rainforest habitats by following savannah corridors that emerged from the Congo rainforest, probably from climate change. When Bantu speakers did move into the rainforest, migration rates were delayed by on average 300 y compared with similar movements on the savannah. Despite unmatched abilities to produce innovations culturally, unfamiliar habitats significantly alter the route and pace of human dispersals.