Where Did Bipedalism First Appear?

In 2000, paleoanthropologists working in Kenya found the teeth and two thigh bones of the six-million-year-old Orrorin tugenensis. The shape of the thigh bones confirms Orrorin was bipedal. The earliest hominid with the most extensive evidence for bipedalism is the 4.4-million-year-old Ardipithecus ramidus.

Where did bipedalism come from?

Bipedalism evolved well before the large human brain or the development of stone tools. Bipedal specializations are found in Australopithecus fossils from 4.2 to 3.9 million years ago, although Sahelanthropus may have walked on two legs as early as seven million years ago.

When did bipedalism occur?

Evidence for bipedalism extends as far back as 4.2 million years ago, perhaps even six million years ago, but stone tools do not appear in the archeological record until 2.6 million years ago—so we can rule out tool-making as an explanation.