Because the timing of the assembly of Africa’s grassland habitats underlies many evolutionary hypotheses, our discovery that they existed much earlier than expected calls for a recalibration of those ideas.
Anthropologists have long thought that our ape ancestors evolved an upright torso in order to pick fruit in forests, but new research from the University of Michigan suggests a life in open woodlands and a diet that included leaves drove apes' upright stature.
The research, more than a decade in the making, pushes back the time frame when apes increased in size and became upright in equatorial Africa to 21 million years ago.