When did human ancestors start walking on two legs?

Anthropologists have been arguing for 20 years about whether Sahelanthropus, a hominin that lived about 7 million years ago, was one of the first bipedal apes

​Anthropologists have been arguing for 20 years about whether Sahelanthropus, a hominin that lived about 7 million years ago, was one of the first bipedal apes Anthropologists have been arguing for 20 years about whether Sahelanthropus, a hominin that lived about 7 million years ago, was one of the first bipedal apes