The harsh landscape that formed millions of years ago in East and South Africa under the influence of constant volcanic eruptions and tectonic shifts, may be the reason why our ancestors became upright walking.
The new study rejects the popular theory that climate change made human ancestors stand on their feet. Previously, scientists hypothesized that climate change led to a decrease in the number of trees and, thus, reduced the natural habitat of the hominid family. However, now archaeologists have come to a different conclusion.
“Our study shows that upright walking may be due to adaptation to the terrain, rather than adaptation to decreasing forests,” said Isabelle Winder, one of the authors of the study at the University of Archeology in York.
From six to two million years ago, our ancestors lived exclusively in Africa - mainly in the east and south, where there was constant tectonic activity. After exploring the area, Winder and her team concluded that our ancestors were attracted not by flat plains, but by rocky gorges. It was there that one could take refuge from predators and safely rest.
But movement over rough terrain requires an almost vertical position of the body, and this contributed to the appearance of upright posture.
“Mountainous terrain consists of uneven and often angular surfaces. Animals that carry their weight on four limbs sometimes fail to stabilize themselves if one or two of them begin to slide,”explained Winder.
To avoid falls, the legs of our ancestors were used to supporting most of the body's weight, and our arms were adapted to stabilize the position and pull the body up.
“The varied terrain may have also contributed to improved cognitive skills such as navigation and communication skills,” added Winder.
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The study was published in the journal Antiquity.