The ancestors of the human species, Australopithecus afarensis, evolved in an open grassland, in a region that was dominated by rainforests much like in Kongo today. How does an open grassland find a niche in a forested region, where it would easily be overgrown by arboreal vegetation?
The Danakil block separated from Ethiopia around 6 million years ago[1, 2], and a coast line formed from faulting of the the block, much like how the coast on Crete has formed,[3] on which erosion from wind that came in from the Sea of Afar maintained a largely treeless open grasslands landscape, where the grazing horse speciated[4] as well as the waterbuck[5] and Australopithecus afarensis.[6]