- Jan Simek
- The Conversation*
This is an important question because many anthropologists view standing or bipedalism — walking on two legs — as a characteristic of “hominins” or modern humans and their ancestors.
It is difficult to explain it in a simple way, because bipedalism did not appear overnight. It was the product of a gradual evolution that began millions of years ago.
Of course, there are no videos of the first person who started walking upright. So how do scientists try to answer the question of how humans moved in ancient times?
Fortunately, the shape of the bones found and how they fit together gives information about how a creature moved when she was alive. And anthropologists can also find evidence of it in the landscape.
In 1994, the first fossils of a hominin species were found in Ethiopia – a subtribe of hominid primates characterized by upright posture and bipedal locomotion – hitherto unknown.
The anthropologists in charge of the new discovery described them as the remains of an adult female belonging to the species Ardipithecus ramidus which they then called“Ardi”.
In the next 10 years they found up to 100 fossils of the Ardi species that were, they said, between 4.2 and 4.4 million years old.
Characteristics of the biped
When the scientists examined the bone collection, they identified certain characteristics that indicated bipedalism.
The structure of the foot, for example, allowed to take steps by propelling with the fingers, as we do today, and that the apes that walk on all fours do not.
The shape of the pelvis and the way the legs fit into it also suggest that the creatures to which the bones belonged walked on two legs.
Ardi’s walk may not have been exactly like ours, but the peculiarities of these fossils more than 4.4 million years old suggest that bipedalism was his natural way of moving.
Anthropologists have also found 40% of the skeleton of a hominin species in Ethiopia that lived millions of years after Ardi.
Because of its similarities with the other fossils found in southern and eastern Africa, they called it Australopithecus afarensis, which is Latin for “southern ape from a distant region.”
Like Ardi, the new fossil was from a female. Anthropologists called her “Lucy”, inspired by Lucy In The Sky With Diamonds, a song by the British band The Beatles that was popular at the time.
Many more fossils of this species have been found – up to 300 individuals – so researchers today know quite a bit about Lucy and her relatives.
Finding a well-preserved part of Lucy’s pelvis allowed them to know that she was a woman. The way his upper legs fitted into her made it clear to them that she was bipedal.
The scientists also found other important evidence of how individuals of the species to which Lucy belonged moved at Laetoli, a Lower Paleolithic site in Tanzania.
Under a layer of volcanic ash from 3.6 million years ago, anthropologists found fossilized footprints.
They are some 70 footprints that extend for about 30 meters, which indicates that they could have been three individuals who walked on two legs and that, due to the age assumed to the footprints, they belonged to the species Australopithecus afarensis.
A hominid whose anatomy was so similar to ours that we can say that it walked like us did not appear in Africa until 1.8 million years ago.
The Standing man was the first to have the long legs and the shorter arms, which would have allowed them to walk, run and move through the landscapes of the Earth as we do today.
It also had a much larger brain than previous bipedal hominins and made and used stone tools known as Achelens.
Anthropologists consider Standing man our close relative and one of the earliest members of our own genus, the Homo.
As you can see, human walking took a long time to develop. It appeared in Africa more than 4.4 million years ago, long before tool-making.
But why did they start walking upright?
May make it easier for them to see predators or allow them to run faster. Or maybe the environment changed and there were fewer trees to climb.
In any case, humans and their ancestors began to walk very early in their evolutionary history.
Although bipedalism began before tool-making, the upright posture left their hands free to make and use tools, eventually becoming one of the hallmarks of humans.
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Eddie is an Australian news reporter with over 9 years in the industry and has published on Forbes and tech crunch.