Anthropologist D. Carl Johanson made a remarkable discovery in Ethiopia of bones that belonged to an ape man (hominid) of the genus Australopithecus, with a skull fragment, shin, and thigh bones dating back to 3 million years ago. This discovery provides new insights into the timeline of human evolution and the emergence of upright walking.
However, despite this discovery, the exact timing of when upright walking emerged in the evolutionary history of humans remains a topic of debate among paleontologists. Fossil analyses suggest that several hominid species were walking on two legs between 5 million to 7 million years ago. The oldest known evidence of upright walking comes from a 7-million-year-old Sahelanthropus tchadensis, whose upper leg bone bears signs of upright walking. However, there is ongoing debate among scientists about whether these features definitively prove a two-legged gait.
Some scientists have raised concerns that the bone attributed to Sahelanthropus tchadensis may have belonged to an ape that occasionally walked upright. This ongoing debate highlights the complexity of interpreting fossil evidence and the need for continued research and analysis in the field of paleoanthropology.
In conclusion, while there is concrete evidence that our ancestors walked on two legs over 3 million years ago, the exact timing of when upright walking emerged in human evolution remains a topic of debate among paleontologists. Ongoing research and analysis are necessary to fully understand this important aspect of human history.