Human ancestors may have walked on two legs 7 million years ago

There is a person by the name ofClare Wilson.

It is thought that the ancestors of humans walked on two legs about 7 million years ago. The finding of a damaged thigh bone is controversial.

Estimates vary for the time when the ancestors of humans and Chimpanzees split. The earliest fossil of a bipedal hominid was found at this time.

There is a thigh bone in the Lake Chad Basin. Almost all of the bone pieces found in 2001 weren't from monkeys.

A few teeth and fragments of a skull were the first hominin fossils to be found. A new and very early hominin species was identified as these.

The estimate was pushed back to between 6 and 7.5 million years ago by a later method of fossil dating.

Aude Bergeret-medina and Roberto Macchiarelli at the University of Poitiers in France were able to identify a femur as potentially belonging to a hominin.

A full analysis of the femur as well as two forearm bones have been published by the University of Poitiers and their colleagues. The team didn't have the right expertise to analyse bones other than the skull.

The only large primate with bones found at the site were the hominin bones.

The researchers compared the thigh and forearm bones from modern humans and extinct hominins and apes. They say that S. tchadensis walked on two legs, similar to modern humans, because of several features of the femur. There is a rough surface at the top of the femur where the buttock muscles attach and thicker sections of the dense outer layer of bone.

They would have preferred to move in a straight line. They would sometimes climb in the trees. Guy says that all the features point to this type of behavior.

Macchiarelli isn't sure. The small angle the femur makes with the pelvis is similar to that seen in apes. It is not stable to walk on two legs.

The features of bipedalism could be why S. tchadensis has some features. He says there is a signal in any primate.

The debate about bipedalism is likely to continue according to Fred Spoor at the Natural History Museum. You can't go back and look for yourself unless you have a time machine.

He says that the australopiths walked on two legs and climbed trees as recently as 4 million years ago. For the first 3 million years of our history, there wasn't a lot of activity.

The American Museum of Natural History in New York has a collection of fossils. She says that it will be important for independent teams of paleoanthropologists to study the fossils.

The journal's title is " Nature."

The revolution in archaeology and human evolution is covered in Our Human Story.