Why We Walk on Two Legs

Introduction

Written with the Assistance of Dual Ai

Bipedalism, or walking on two legs, is one of the defining characteristics of humans. But why do we walk this way? There are many hypotheses about the evolution of bipedalism. Still, the most likely explanation is that it allowed our early ancestors to travel long distances more efficiently, as in they could go farther while using fewer calories and explore the world even further. 

While Bipedalis may not be the thing that “makes us Human,” as I believe there is no one such thing, it is an aspect of our evolutionary history and our current lives that cannot be ignored; its importance in understanding who we are is critical. 

The advantages of bipedalism

Bipedalism has many advantages over quadrupedalism, or walking on four legs. For one, it allows us to travel long distances more efficiently. This is because bipedalism frees up our hands, which we can use to carry tools or food. Additionally, bipedalism allows us to see over tall grass and other obstacles, which gives us a better view of our surroundings.

Bipedalism also has some social advantages. For example, it allows us to stand face-to-face with each other, which is essential for communication and cooperation. Additionally, bipedalism allows us to use our hands for gestures and other nonverbal communication.

We can run, walk long distances, and get around places no other animals can, thanks to these strange spindly things that come off the bottom of our torsos. But being bipedal is not always a good thing. As we will soon see. 

The disadvantages of bipedalism

Bipedalism also has some disadvantages. For one, it puts more stress on our legs and feet. Additionally, bipedalism makes climbing trees or running as fast as quadrupeds more difficult. But these are the simple things that make the disadvantages of bipedalism apparent. 

Less apparent is the back strain, the heavyweight our bones have to move around to keep us upright. It is a delicate balancing act. As Dr. Jeremy DeSilva put it in his book First Steps; How Walking Made Us Human (Which I highly recommend), he mentions that we are always constantly in a controlled fall. We put one leg forward and fall controlled until we throw the other leg out in front of us. This is very true when you think about it, and there is so much room for error when doing this. 

We fall constantly, and the older we get, the more dangerous and likely these events are to occur. Taking a tumble on the football field when you are 18 and falling on your hip when you are 80 will feel very different. 

The evolution of bipedalism

The exact evolutionary history of bipedalism is still a matter of debate, but it is thought to have evolved over millions of years. We have examples of bipedalism that may date back to seven million years ago, close to our separation from the pan family. Sahelanthropus tchadensis may be the oldest hominin we know of. But it is still debated on whether or not it was bipedal, to begin with. 

The next candidate would be the millennial man, or Orrorin Tungunensis, which dates to around 5-6 million years ago. 

Another great example of ancient bipedalism is the Laetoli footprints in Tanzania. It contains multiple tracks of footprints made by something remarkably human, thought to be Australopithecus afarensis (save the site A trackway). We can see how these footprints were made because they were imprinted on top of recently deposited volcanic ash, so we can even reliably date them to about The Laetoli footprints are a series of hominin footprints that were discovered in Laetoli, Tanzania, in 1978. The footprints are dated to 3.6 million years ago, and they are the oldest known direct evidence of human or human-like bipedalism.

The footprints were discovered by Mary Leakey and her team during an archaeological excavation at Laetoli. The footprints were found in a layer of volcanic ash that had been laid down by a volcano that erupted about 3.6 million years ago. The ash layer had preserved the footprints in excellent condition.

The footprints are about 1.7 meters long and 0.7 meters wide. They show that the hominin who made them was walking upright, with its feet flat on the ground. The footprints also show that the hominin was walking at a slow pace.

The Laetoli footprints are a significant discovery because they provide direct evidence of human or human-like bipedalism at a time when it is thought that hominins were still evolving from ape-like ancestors. The footprints also provide evidence that hominins were walking upright in East Africa at least 3.6 million years ago.

The Laetoli footprints are displayed at the National Museum of Natural History in Washington, D.C.

Conclusion

Bipedalism is a complex trait with many advantages and disadvantages. It is thought to have evolved over millions of years, and it has played a major role in the evolution of humans.

References

• Day, M. H. (1986). Hominid footprints from Laetoli, Tanzania. Nature, 322(6081), 17-21.
• Lovejoy, C. O. (1981). The evolution of human walking. Scientific American, 244(5), 118-125.
• Tuttle, R. H. (1987). The primate origins of human bipedalism. New York: Columbia University Press.