In Ethiopia, an anthropologist named D. Carl Johanson discovered a skull fragment, shin and thigh bones of a 3-million-year-old man. The bones belonged to an ape man (hominid) of the genus Australopithecus. At a news conference, the 30-year-old scientist announced that they have absolute, concrete evidence that our ancestors walked on two legs over 3 million years ago.
However, not all paleoanthropologists are convinced that these features prove a two-legged gait. Some scientists think the bone belonged to an ape that may have walked upright at times. Fossil analyses suggest that several hominid species ambled around on two legs about 5 million to 7 million years ago. An upper leg bone of the oldest known, 7-million-year-old Sahelanthropus tchadensis, bears signs of upright walking including an inner projection near the hip joint.
Questions or comments on this article can be directed to email@example.com. Maria Temming is the assistant editor at Science News Explores, who has bachelor’s degrees in physics and English and a master’s in science writing. This article was supported by readers like you by donating today to invest in quality science journalism.