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Portrait of a member of the robust australopithecine group. (Photo: mc.maricopa) |
Brain size and the ability to stand upright are two of the main factors that distinguish humans from large primates. Researchers now indicate that millions of years ago, learning to walk on two legs was a challenging endeavor.
A re-examination of the ankle bones of ancient individuals has revealed that their gait was not as stable as previously assumed. They exhibited bow-leggedness.
Researchers examined specimens from the robust australopithecine group that lived around 2 million years ago. Compared to modern humans, they had larger teeth, stronger chewing muscles, and a robust skull with smaller brains.
Their legs were considered very similar to those of modern humans, indicating that they did indeed walk on two legs. “We found that in the specimens of robust australopithecines, there are features in the ankle that influenced this bipedalism,” said Gary Schwartz, an anthropologist at Arizona State University.
“By examining the position where the tibia meets the ankle bone, we discovered that the tibia would have to curve inward,” Gary revealed.
Fossils of human ancestors have existed for 6 million years. However, scientists believe that the Homo genus only appeared about 1.8 million years ago—around the time australopithecines may have evolved into the early Homo habilis species, which had larger brains but never exceeded the brain size of a 12-year-old today.
Schwartz compared the ancient ankle bones of various australopithecine species with those of modern gorillas, chimpanzees, and humans. The findings support the view that bipedal walking evolved only once, and this transition was not easy.
T. An
