Bipedalism

Bipedalism is a significant mode of mobility that involves walking on two feet. (Napier, 2019). It is a distinguishing trait of both humans and some of the other primates, like chimpanzees and gorillas but they are frequent bipedal while humans are habitual bipedal. The emergence of bipedalism, which is considered to have occurred in our predecessors more than 4 million years ago, had a significant influence on how we have evolved. The word bipedal is derived from Latin words ‘bi’ meaning two and ‘ped’ meaning foot.

Bipedal animals

Humans, lizards, birds, cockroaches, jerboas also known as hopping mice.

1. Reptiles: Several lizard species, including the spiny-tailed iguana (genus Ctenosaura), the fastest reptile in the world, switch to a bipedal posture during rapid sprint locomotion.
2. Early Reptiles and Lizards: The earliest known biped was a bolosaur named Eudibamus, which lived 290 million years ago. Its long rear legs, narrow forelegs, and distinctive joints imply bipedalism. The species vanished later in the Permian (Berman; David, 2000).
3. Birds: Birds are bipedal when on the ground.
4. Archosaurs: Bipedalism occurred more than once among the group of animals known as archosaurs, which also includes crocodiles and dinosaurs. Both dinosaurs are thought to have originated as fully bipedal creatures like the Eoraptor. Bipedal walking has been re-evolved in several dinosaur lineages, including the iguanodons (Hutchinson, 2006).
5. Mammals: Bipedal walking is unusual because most mammals walk on four legs. All primates have some degree of the capacity to walk on two feet, however some species prefer to move around on land by adopting quadrupedal locomotion. Apart from primates, two-legged animals include leaping mice, kangaroo rats and mice, springhares, and macropods (wallabies, kangaroos, and their relatives). Only a select few creatures, including apes, walk on two legs rather than jumping. The tree kangaroo and, in some circumstances, the ground pangolin are examples (Angela, 1998).

Advantages of bipedalism

1. Bipedalism involves raising the head, it improves vision, allows wading animals to access deeper water, and gives mouth-reaching animals the ability to reach higher food sources.
2. When an animal is upright, their non-moving limbs can be used for a variety of other activities, such as manipulation in primates and rodents, flight in birds, fighting in bears and great apes, digging in  pangolins and the large monitor lizard, or camouflage in some octopus species.
3. The endurance running hypothesis states that although initially slower, bipedalism has allowed humans to outrun some other animals over extremely long distances.
4. The evolution of bipedalism is thought to have been influenced by a number of factors, such as changes in habitat and climate. When they moved from deep forests to wide grasslands, our ancestors faced more predators. Bipedalism allowed them to see predators more clearly and move away from them more quickly.

Dietary changes might have contributed to the evolution of bipedalism. Our ancestors had to be able to travel great distances to obtain food as their consumption of meat increased. Bipedalism made this happen. Bipedalism has had a huge impact on our evolutionary process. It has affected human anatomy, culture, and attitude. It’s a defining quality of the human condition.

The Science of Bipedalism

Features of human body like –

1.     Flat and broad feet

2.     Longer legs

3.     Upright posture

4.     Forward tilted pelvis

5.    Curved spine

 Enabled us to move swiftly on two legs while walking and running.

Bipedalism’s Effects on Behaviour

Bipedalism has a variety of behavioural impacts that have been seen in humans. For instance, technology has boosted our ability to hunt and gather by enabling us to transport tools and other materials. Bipedalism has allowed us to expand our range and establish ourselves in new locations because it has allowed us to traverse large distances (Anapol et al., 2004).

The Cultural Effects of Bipedalism

For humans, bipedalism has had a variety of cultural ramifications. For instance, it has made it possible for humans to create new kinds of speech. Speech is regulated by the same brain regions that control bipedal movement. Walking on two legs may have contributed to the development of the brain’s speech and syntax-related areas. We have also been able to create new kinds of architecture and art because of bipedalism.

The Prospects for Bipedalism

The intriguing narrative of the evolution of bipedalism has significantly benefited our species. Because the story is still being written, it is difficult to anticipate what the future of bipedalism will be. But there is no denying that the ability to stand on two feet is one of the characteristics that sets humans apart from other animals, and it is quite likely to stay that way for a very long time. Bipedalism will definitely continue to be a distinctive characteristic of our species for an extended period of time.

Hypotheses on bipedalism

There are numerous hypotheses regarding the mechanisms underlying the development of bipedalism in humans. Some hypotheses for the development of human bipedalism include the following (Tuttle, 2023)

1. According to the Savannah hypothesis, bipedalism developed so that our forebears could look over tall grass and other flora in wide grasslands (Dean, 2000).
2. The endurance running hypothesis proposes that bipedalism originated as a mechanism for our ancestors to sprint great distances, giving them an edge in hunting and evading predators. They would have been better able to hunt and avoid predators as a result.
3. According to diet theory, bipedalism developed so that our ancestors could consume more meat. It would have been simpler to hunt and gather food if they had been able to walk upright and carry tools and other items.

Conclusion

The complicated trait of bipedalism is thought to have evolved gradually through time. Our physiology, psychology, and society have all been significantly impacted by the development of bipedalism. In recent times, bipedal robots have been developing. These machines have started applying ideas learned from the study of human and animal mobility to make the robots bipedal.

References

• Anapol, F., German, R. Z., & Jablonski, N. G. (2004). Shaping Primate Evolution: Form, Function, and Behavior. Cambridge University Press.
• Angela Burk and others, The Phylogenetic Position of the Musky Rat-Kangaroo and the Evolution of Bipedal Hopping in Kangaroos (Macropodidae: Diprotodontia), Systematic Biology, Volume 47, Issue 3, 1 September 1998, Pages 457–474, https://doi.org/10.1080/106351598260824 . Accessed on 17 May 2023.
•  Auletta, M., et al. (2011). “The evolution of bipedalism in hominins: A new hypothesis.” Journal of Human Evolution 60(6): 699-718.
• Berman, David S.; et al. (2000). “Early Permian Bipedal Reptile“. Science. 290 (5493): 969–972. 
• Cartmill, M. (1972). “The evolution of hominid bipedalism.” Annual Review of Anthropology 1: 101-120.
• Day, M. H. (1986). “The hominids of East Africa: Their environment and evolution.” New York: Academic Press.
• Dean, F. 2000. Primate Diversity. W.W. Norton & Company, Inc: New York. Print.
• Hutchinson, J. W. (2006). The evolution of locomotion in archosaurs. Comptes Rendus Palevol, 5(3–4), 519–530. https://doi.org/10.1016/j.crpv.2005.09.002 . Accessed on 17 May 2023.
• Lovejoy, C. O. (1988). “The evolution of human walking.” Scientific American 259(5): 118-125.
• Napier, J. (2019, February 11). Bipedalism. Encyclopedia Britannica. https://www.britannica.com/science/bipedalism . Accessed on 17 May 2023.
• Stern, J. (2002). “The evolution of bipedalism in hominins.” Annual Review of Anthropology 31: 279-301.
• Tuttle, R. Howard (2023, March 28). Human evolution. Encyclopedia Britannica. https://www.britannica.com/science/human-evolution . Accessed on 17 May 2023.
• White, T. D. (1989). “Human bipedalism: A new look.” Annual Review of Anthropology 18: 63-90.