Post 2 of 2 in the “Entertaining but Rejected Theories of Bipedalism”
The catalyst inciting humans’ evolution to efficiently walk on two legs has been at the center of intense debate within the anthropological community. Researchers worldwide have rushed to develop new theories to provide insights revealing why early human ancestors began walking on two legs. While there are many data driven, believable explanations for human bipedalism, there are also plenty that push the boundaries of plausibility and have been deemed outlandish by the community such as the “Aquatic Ape Theory”
One of the most outlandish theories, albeit creative, is the “Aquatic Ape Theory.” Developed by Sir Alister Hardy, the aquatic ape theory is an alternative explanation of human evolution claiming that contemporary homo sapiens evolved from aquatic ancestors. Its supporters theorize bipedalism and the “…mastery of the erect posture arose by toddling but performed in the water” (Hardy 4). Sir Alister Hardy believed that humans’ ability to walk on two legs came from their aquatic origins as wading apes, and there is some support for the idea. Famous anthropologist Richard Wrangham conducted research on the importance of an alternate food supply called Underground Storage Organs (USOs), which require one to wade through shallow waters to gather them. Wrangham’s team found that baboons do use USOs as a fallback food and baboons “…emphasis on USOs could have favored bipedal wading…[which] could have helped select for full-time bipedal adaptations” (Wrangham 637). Wrangham applied proprietary data that his team gathered to the relatively outlandish hypothesis and showed that it may have some validity; however, many others criticized it.
Some leading critiques include accusations that the Aquatic Ape Theory cherry-picks its traits and ignores the abundance of lurking semi-aquatic predators such as hippos and crocodiles (DeSilva 33). Other critiques cite the fossil record that shows aquatic adaptations stopped before the genus Homo about 2 million years ago; therefore, humans and their bipedal traits could not have evolved from aquatic animals (Langdon 490). Therefore, the “Aquatic Ape Theory” has been deemed incorrect despite its ability to fascinate and incite one’s imagination.
Hardy’s Aquatic Ape Theory may seem believable and is certainly exciting; however, most anthropologists, except for Elaine Morgan, have disregarded it. The large amounts of contrarian evidence have suggested that it is merely a red herring, but it does not mean that the true reasons are not out there waiting to be discovered.
References:
DeSilva, Jeremy. First Steps: How Upright Walking Made Us Human. Harper, an Imprint of HarperCollinsPublishers, 2022.
Hardy, Alister. “WAS MAN MORE AQUATIC IN THE PAST?” New Scientist, 17 Mar. 1960.
Langdon, John H. “Umbrella hypotheses and parsimony in human evolution: A critique of the Aquatic Ape Hypothesis.” Journal of Human Evolution, vol. 33, no. 4, Oct. 1997, pp. 479–494, https://doi.org/10.1006/jhev.1997.0146.
Wrangham, Richard, et al. “Shallow‐water habitats as sources of fallback foods for hominins.” American Journal of Physical Anthropology, vol. 140, no. 4, 3 Nov. 2009, pp. 630–642, https://doi.org/10.1002/ajpa.21122.