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 humans first walk upright?

From at least 6 to 3 million years ago, early humans combined apelike and humanlike ways of moving around. Fossil bones like the ones you see here record a gradual transition from climbing trees to walking upright on a regular basis. Sahelanthropus may have walked on two legs.

How did bipedalism begin?

How did bipedalism begin? There are various theories about when our ancestors started walking upright, but a popular view is that perhaps about 7-million years ago, early hominids began to adapt to a climate that was cooling globally.