Modern humans' ancestors coaxed onto two legs by rough terrain, study finds
The research challenges the common theory that early hominins - members of the broad human family - were forced onto two feet because climate change reduced the number of trees they could live in. According to the new hypothesis, it is not why they left the forests, but where they went, that explains the evolution.
The rugged landscape created by volcanic eruptions and tectonic plate shifts in east and south Africa millions of years ago may be what prompted our human ancestors to start walking on two legs, a study says.
The research, published in the journal Antiquity, challenges the common theory that early hominins - members of the broad human family - were forced onto two feet because climate change reduced the number of trees they could live in.
According to the new hypothesis, it is not why they left the forests, but where they went, that explains the evolution.
"Our research shows that bipedalism may have developed as a response to the terrain, rather than a response to climatically-driven vegetation changes," said study co-author Isabelle Winder of Britain's University of York.
Between six and two million years ago, our ancestors lived exclusively in Africa - mainly in the east and south, where much tectonic activity took place.
Winder and her team compared geological changes with evolution of hominin anatomy over millions of years, and concluded it was likely that our early tree-living ancestors were attracted not to flat plains as widely thought, but rocky outcrops and gorges, which would have offered shelter from predators and made it easier to corner pray.