evolution
Pre-humans walked upright millions of years ago
Depiction of the modes of locomotion practiced by Sahelanthropus. Already seven million years ago, early human ancestors walked through Africa on two legs. photo
© Sabine Riffaut, Guillaume Daver, Franck Guy/PALEVOPRIM/CNRS
The earliest history of mankind is complicated. Now researchers want to have gotten a little further. It’s about when our ancestors learned to walk.
Already seven million years ago, early human ancestors walked through Africa on two legs. This is now confirmed by studies of two forearm bones and one femur of Sahelanthropus tchadensis found in Chad. Researchers from France and Chad report this in the journal “Nature”.
The condition of the femur indicates that pre-humans usually walked on two legs on the ground, but also climbed trees. Studies of the forearm bones show that S. tchadensis could also move in trees with the help of its arms and firm grips.
The team of paleontologists includes researchers from the University of Poitiers and the National Scientific Research Center (CNRS) in France, and the University of N’Djaména and the National Research and Development Center (CNRD) in Chad.
After finding a skull bone and teeth in the Djurab desert in northern Chad in 2001, researchers concluded from the location where the spine is anchored in the skull that S. tchadensis moved on two legs. The now examined forearm and thigh bones are also assigned to pre-humans, since no other large primate was discovered at the excavation site. According to the researchers, it is not possible to say whether the skull and bones come from the same individual.
Walking upright very early in human history
The researchers conclude that the study presented here reinforces the idea that upright gait was acquired very early in human history. At seven million years old, Sahelanthropus tchadensis is believed to be the oldest representative of mankind. His forearm bones indicated that he was already upright, but that he was also moving with all four limbs when climbing trees with the firm grip of his hands. This differs markedly from the four-legged nature of gorillas and chimpanzees, which also move across the plain on all fours, leaning on the backs of their hands.
Years ago, other studies had confirmed that human ancestors were walking upright in Africa several million years ago. The pre-human species Orrorin tugenensis is said to have walked on two legs in Kenya around six million years ago, and Australopithecus also in Africa around four million years ago. How human-like the various ancestors were and where they should be placed on the human lineage is a matter of controversy among researchers.