Anthropologist D. Carl Johanson uncovered a 3-million-year-old man’s skull fragment, shin and thigh bones in Ethiopia. The bones belonged to an ape man (hominid) of the genus Australopithecus. At a news conference, the 30-year-old scientist announced that this discovery provides concrete evidence that our ancestors walked on two legs over 3 million years ago.
Scientists have long debated whether several hominid species ambled around on two legs about 5 million to 7 million years ago. An upper leg bone of the oldest known, Sahelanthropus tchadensis, which is 7 million years old, bears signs of upright walking including an inner projection near the hip joint, according to fossil analyses. However, not all paleoanthropologists are convinced those features prove a two-legged gait. Some scientists believe that the bone belonged to an ape that may have walked upright at times.
As for the discovery made by Johanson, some experts believe it is just another piece of evidence supporting the idea that our ancestors walked on two legs for millions of years. Others argue that more research is needed before we can be certain about this theory. Nonetheless, the discovery has sparked interest among scientists and laypeople alike and has prompted further investigation into human evolutionary history.