Several million years ago, human ancestors began striding around on two legs, in what was a key moment in the evolution of modern humans. But the question of whether each species of prehuman left treetops behind and made their home in grasslands has not always been easy to discern from fossils, which can provide conflicting evidence.

Now, a team of scientists from Dartmouth College that has been studying a former hunter-gatherer population in Uganda has found clues among living humans that further muddies the picture, making it clear that even a modern human foot can be useful in impressive feats of climbing.