This is a crucial question, as many anthropologists view bipedalism (which means walking on two feet) as one of the most important characteristics of modern humans and their ancestors. Bipedalism didn’t just happen one day. It is therefore difficult to provide a simple answer. It was a gradual evolution that started many million of years ago.
There are no videos of anyone standing upright for the first time. How can scientists answer questions about the movement of people in the ancient past? The bones of an animal and how they fit together can tell you a lot about its movement when it was alive. Anthropologists can also find evidence in the landscape to show how ancient humans walked.
The first fossils of an unidentified hominin were discovered in Ethiopia in 1994. The new discovery was made by anthropologists Ardipithecus . It was an adult female person, Ardipithecus RAMIdus . They were nicknamed “Ardi” and found more than 100 fossils belonging to Ardi’s species. These fossils were dated between 4.2million and 4.4million years.
Scientists identified some characteristics in this collection of bones that suggested bipedalism when they examined them. For example, the foot had a structure that allowed for the type of toe pushoff we enjoy today. This is something that four-legged apes don’t have. It was clear that upright walking was possible from the shape of the pelvic bones and the way the legs were placed under the pelvis. Although Ardi may not have walked exactly like we do today, bipedalism is a common way of moving in these fossils that were found around 4.4 million years ago.
Anthropologists had already discovered the almost 40% complete skeleton of a hominin-like species, which was about one million years after Ardi in Ethiopia. They called it Australopithecus because it was similar to fossils from eastern and southern Africa.
Researchers now have a lot of information about Lucy and her family thanks to the addition of more fossils from this specie – over 300 individuals.A model of Lucy and other Australopithecus.afarensis Skeletal Fossils found in East Africa in 1974. SmithsonianCC-BY-SA
Lucy had a partially preserved pelvis. This was how anthropologists determined she was female. The way the pelvis and upper leg bones were connected showed that she could walk on two legs. However, later discoveries of A. Afarensis does include feet and indicates bipedal walking.
Scientists also found other amazing evidence about Lucy’s movements at the Laetoli site, Tanzania. Anthrologists discovered fossilized footprints under a layer of volcanic Ash that dates back to 3.6million years ago. These tracks run for nearly 100 feet and 70 prints indicate that at least three people were standing on their feet. The presumed age of the makers suggests that they were likely Australopithecus.
These tracks show that hominins were walking on two legs but their gait is quite different to ours. Laetoli still provides strong evidence for bipedalism about 3.5 million years ago.
An African hominin with an anatomy so similar to ours that it could say it walked like we do was not discovered until 1.8 million years old. The first hominin to possess the lengthened legs and shorter arms required to walk, run, and move around the Earth’s landscapes like we do today is Homo erectus. The brain of Homo erectus was larger than that of earlier bipedal hominins. It also made and used stone tools , called Acheulean implementations. Anthropologists consider Homo to be our closest relative and an early member our own genus Homo.
As you can see, it took humans a long time to learn how to walk. It was discovered in Africa over 4.4 million years ago. This is long before the advent of tool-making.
Why do hominins stand upright? It may have allowed them to see prey more easily or run faster. Or maybe the environment was different and there were less trees to climb.
Humans and their ancestors started walking very early in human evolution. Despite the fact that bipedalism was before tool-making existed, upright posture allowed the hands to create and use tools. This became a hallmark of humankind.