Aquatic ape hypothesis
The aquatic ape hypothesis (AAH), also referred to as aquatic ape theory (AAT) or the waterside hypothesis of
The theory developed before major discoveries of ancient hominin fossils in East Africa.[5][6] The hypothesis was initially proposed by the English marine biologist Alister Hardy in 1960, who argued that a branch of apes was forced by competition over terrestrial habitats to hunt for food such as shellfish on the coast and seabed, leading to adaptations that explained distinctive characteristics of modern humans such as functional hairlessness and bipedalism.[7] The popular science writer Elaine Morgan supported this hypothesis in her 1972 book The Descent of Woman. In it, she contrasted the theory with zoologist and ethnologist Desmond Morris's theories of sexuality, which she believed to be rooted in sexism.[8]
Anthropologists do not take the hypothesis seriously: John Langdon characterized it as an "umbrella hypothesis" (a hypothesis that tries to explain many separate traits of humans as a result of a single adaptive pressure) that was not consistent with the fossil record, and he said that its claim that it was simpler and therefore more likely to be true than traditional explanations of human evolution was not true.[9] According to anthropologist John Hawkes, the AAH is not consistent with the fossil record. Traits that the hypothesis tries to explain evolved at vastly different times, and distributions of soft tissue the hypothesis alleges are unique to humans are common among other primates.[5]
History
million years ago ) |
In 1942 the German
Independently of Westenhöfer's writings, the
The idea was generally ignored by the
While traditional descriptions of 'savage' existence identified three common sources of sustenance: gathering of fruit and nuts, fishing, and hunting,[18] in the 1950s, the anthropologist Raymond Dart focused on hunting and gathering as the likely organizing concept of human society in prehistory,[19] and hunting was the focus of the screenwriter Robert Ardrey's 1961 best-seller African Genesis. Another screenwriter, Elaine Morgan, responded to this focus in her 1972 Descent of Woman, which parodied the conventional picture of "the Tarzanlike figure of the prehominid who came down from the trees, saw a grassland teeming with game, picked up a weapon and became a Mighty Hunter,"[20] and pictured a more peaceful scene of humans by the seashore. She took her lead from a section in Morris's 1967 book which referred to the possibility of an Aquatic Ape period in evolution, his name for the speculation by the biologist Alister Hardy in 1960. When it aroused no reaction in the academic community, she dropped the feminist criticism and wrote a series of books–The Aquatic Ape (1982), The Scars of Evolution (1990), The Descent of the Child (1994), The Aquatic Ape Hypothesis (1997) and The Naked Darwinist (2008)–which explored the issues in more detail. Books published on the topic since then have avoided the contentious term aquatic and used waterside instead.[21][22]
The Hardy/Morgan hypothesis
Hardy's hypothesis as outlined in New Scientist was:
My thesis is that a branch of this primitive
shell fish, sea-urchins etc., in the shallow waters off the coast. I suppose that they were forced into the water just as we have seen happen in so many other groups of terrestrial animals. I am imagining this happening in the warmer parts of the world, in the tropical seas where Man could stand being in the water for relatively long periods, that is, several hours at a stretch.[7]
Hardy argued a number of features of modern humans are characteristic of aquatic adaptations. He pointed to humans' lack of body hair as being analogous to the same lack seen in
The diving reflex is sometimes cited as evidence. This is exhibited strongly in aquatic mammals, such as seals, otters and dolphins. It also exists as a lesser response in other animals, including human babies up to 6 months old (see infant swimming). However adult humans generally exhibit a mild response.
Hardy additionally posited that bipedalism evolved first as an aid to wading before becoming the usual means of human locomotion,[28][29] and tool use evolved out of the use of rocks to crack open shellfish.[28][25] These last arguments were cited by later proponents of AAH as an inspiration for their research programs.
Morgan summed up her take on the hypothesis in 2011:
Waterside hypotheses of human evolution assert that selection from wading, swimming and diving and procurement of food from aquatic habitats have significantly affected the evolution of the lineage leading to Homo sapiens as distinct from that leading to Pan.[30]
Reactions
The AAH is generally ignored by anthropologists, although it has a following outside academia and conferences on the topic have received celebrity endorsement, for example from David Attenborough.[2] Despite being debunked, it returns periodically, being promoted as recently as 2019.[3]
Academics who have commented on the aquatic ape hypothesis include categorical opponents (generally members of the community of academic
Overall, it will be clear that I do not think it would be correct to designate our early hominid ancestors as 'aquatic'. But at the same time there does seem to be evidence that not only did they take to water from time to time but that the water (and by this I mean inland lakes and rivers) was a habitat that provided enough extra food to count as an agency for selection.[31]
Critiques
The AAH is considered to be a classic example of pseudoscience among the scholarly community,[32][33][34] and has been met with significant skepticism.[35] The Nature editor and paleontologist Henry Gee has argued that the hypothesis has equivalent merit to creationism, and should be similarly dismissed.[6]
In a 1997 critique, anthropologist John Langdon considered the AAH under the heading of an "umbrella hypothesis" and argued that the
In a blog post originally published in 2005 and continually updated since, anthropologist John D. Hawks said that anthropologists don't accept the AAH for several reasons. Hardy and Morgan situated the alleged aquatic period of human nature in a period of the fossil record that is now known not to contain any aquatic ancestors. The traits the AAH tries to explain actually evolved at wildly different time periods. The AAH claims that the alleged aquatic nature of humanity is responsible for human patterns of hair, fat, and sweat, but actually all of these things are similar in humans to other primates. To the extent they are exceptional in any primate relative to other primates, or in primates relative to other mammals, they are exceptional for well-understood thermodynamic reasons. [5]
Palaeontologist Riley Black concurred with the pseudoscience label, and described the AAH as a "classic case of picking evidence that fits a preconceived conclusion and ignoring everything else".[36] Physical anthropologist Eugenie Scott has described the aquatic ape hypothesis as an instance of "crank anthropology" akin to other pseudoscientific ideas in anthropology such as alien-human interbreeding and Bigfoot.[37]
In The Accidental Species: Misunderstandings of Human Evolution (2013), Henry Gee remarked on how a seafood diet can aid in the development of the human brain. He nevertheless criticized the AAH because "it's always a problem identifying features [such as body fat and hairlessness] that humans have now and inferring that they must have had some adaptive value in the past." Also "it's notoriously hard to infer habits [such as swimming] from anatomical structures".[38]
Popular support for the AAH has become an embarrassment to some anthropologists, who want to explore the effects of water on human evolution without engaging with the AAH, which they consider "emphasizes adaptations to deep water (or at least underwater) conditions". Foley and Lahr suggest that "to flirt with anything watery in paleoanthropology can be misinterpreted", but argue "there is little doubt that throughout our evolution we have made extensive use of terrestrial habitats adjacent to fresh water, since we are, like many other terrestrial mammals, a heavily water-dependent species." But they allege that "under pressure from the mainstream, AAH supporters tended to flee from the core arguments of Hardy and Morgan towards a more generalized emphasis on fishy things."[39]
In "The Waterside Ape", a pair of 2016 BBC Radio documentaries, David Attenborough discussed what he thought was a "move towards mainstream acceptance" for the AAH in the light of new research findings. He interviewed scientists supportive of the idea, including Kathlyn Stewart and Michael Crawford who had published papers in a special issue of the Journal of Human Evolution[40] on "The Role of Freshwater and Marine Resources in the Evolution of the Human Diet, Brain and Behavior".[41] Responding to the documentaries in a newspaper article, paleoanthropologist Alice Roberts criticized Attenborough's promotion of AAH and dismissed the idea as a distraction "from the emerging story of human evolution that is more interesting and complex". She argued that AAH had become "a theory of everything" that is simultaneously "too extravagant and too simple".[42][43]
Philosopher
In 1995, paleoanthropologist
Reactions of Hardy and Morgan
Alister Hardy was astonished and mortified in 1960 when the national Sunday papers carried banner headlines "Oxford professor says man a sea ape", causing problems with his Oxford colleagues.
Elaine Morgan's 1972 book Descent of Woman became an international best-seller, a
Related academic and independent research
Wading and bipedalism
AAH proponent Algis Kuliukas, performed experiments to measure the comparative energy used when lacking orthograde posture with using fully upright posture. Although it is harder to walk upright with bent knees on land, this difference gradually diminishes as the depth of water increases[53] and is still practical in thigh-high water.[54]
In a critique of the AAH, Henry Gee questioned any link between bipedalism and diet. Gee writes that early humans have been bipedal for 5 million years, but our ancestors' "fondness for seafood" emerged a mere 200,000 years ago.[55]
Diet
Evidence supports aquatic food consumption in
In their 1989 book The Driving Force: Food, Evolution and The Future, Michael Crawford and David Marsh claimed that omega-3 fatty acids were vital for the development of the brain:[63]
A branch of the line of primitive ancestral apes was forced by competition to leave the trees and feed on the seashore. Searching for oysters, mussels, crabs, crayfish and so on they would have spent much of their time in the water and an upright position would have come naturally.
Crawford and Marsh opined that the brain size in aquatic mammals is similar to humans, and that other primates and carnivores lost relative brain capacity.
Biologists Caroline Pond and Dick Colby were highly critical, saying that the work provided "no significant new information that would be of interest to biologists" and that its style was "speculative, theoretical and in many places so imprecise as to be misleading."[72] British palaeontologist Henry Gee, who remarked on how a seafood diet can aid in the development of the human brain, nevertheless criticized AAH because inferring aquatic behavior from body fat and hairlessness patterns is an unjustifiable leap.[38]
Diving behavior and performance
Professor of animal physiology and experienced scuba and freediver Erika Schagatay researches human diving abilities and oxygen stress. She suggests that such abilities are consistent with selective pressure for underwater foraging during human evolution, and discussed other anatomical traits speculated as diving adaptations by Hardy/Morgan.[73] John Langdon suggested that such traits could be enabled by a human developmental plasticity.[74]
See also
References
- ISBN 978-0-367-14548-4.
- ^ S2CID 5456280.
most practicing anthropologists are unbothered by the Aquatic Ape Theory (AAT) and its advocates, except perhaps when a student brings it up in lecture
- ^ ISBN 9781032231778.
- ISBN 978-0-313-35507-3.
- ^ a b c Hawks JD (4 August 2009). "Why anthropologists don't accept the Aquatic Ape Theory" (Blog post).
- ^ S2CID 849419.
Where does this leave us? The AAH has been around for more than 50 years. No significant evidence has accumulated in its favor over that time, and the expansion of the fossil and archeological record has filled many of the gaps that made Hardy's original idea seem plausible.
- ^ a b Hardy 1960
- ^ Morgan 1972, p. 3-9.
- ^ a b Langdon 1997.
- ^ Westenhöfer 1942, p. 148.
- ^
Westenhöfer M (1942). Der Eigenweg des Menschen. Dargestellt auf Grund von vergleichend morphologischen Untersuchungen über die Artbildung und Menschwerdung. Berlin: Verlag der Medizinischen Welt, W. Mannstaedt & Co. pp. 309–312. OCLC 311692900.
- ISBN 978-3-533-01969-5.
- .
- ^ a b Hardy 1960.
- JSTOR 985209.
- S2CID 11120840.
- ISBN 978-0-09-948201-7.
- ^ Morgan LH (1877). Ancient Society. New York: Henry Holt & Co. p. 10. Retrieved 29 October 2016.
- ^ Dart RA (1953). "The Predatory Transition from Ape to Man". International Anthropological and Linguistic Review. 1 (4). Retrieved 29 October 2016.
- ^ Morgan 1972, p. 11.
- ^ Vaneechoutte, Kuliukas & Verhaegen 2011
- ISBN 978-0-367-14548-4.
- ^ Morgan 1990, pp. 69–79.
- ^ Langdon 1997, pp. 483.
- ^ a b Langdon 1997, pp. 487.
- ^ Wood FJ (1929). Man's Place among the Mammals. Longmans, Green & co. p. 309. Retrieved 4 February 2017.
- ISBN 978-1-135-43212-6.
- ^ a b Hardy 1960, p. 645.
- ^ Langdon 1997, pp. 481.
- ISBN 978-1-60805-244-8. Retrieved 4 February 2017.
- ^ Reynolds V (1991). Cold and Watery? Hot and Dusty? Our Ancestral Environment and Our Ancestors Themselves: an Overview. p. 340. in RoedeWindPatrickReynolds 1991
- ISBN 978-0-313-33673-7.
- ISBN 978-0-316-58812-6.
- .
- ISBN 978-3-540-69930-9.
- ^ Black, Riley (31 May 2012). "Mermaids Embodies the Rotting Carcass of Science TV". Wired. Retrieved 1 May 2023.
- ^ Frazier K (2015). "Quacks and cranks, GMOs and climate, science and philosoph—CFI Conference covers it all". Skeptical Inquirer. 39 (5): 12. Retrieved 25 February 2017.
- ^ ISBN 978-0-226-04498-9. Retrieved 6 January 2017.
- S2CID 849419.
- ^ Journal of Human Evolution Volume 77, Pages 1-216 (December 2014)
- ^ a b Attenborough D (2016). "The Waterside Ape". BBC Radio 4.
- ^ "It's time we let go of the 'aquatic ape' myth." The i Newspaper, 17 September 2016, page 23
- ^ Maslin M, Roberts A (2018). "Sorry David Attenborough, we didn't evolve from 'aquatic apes' – here's why". theconversation.com. Retrieved 27 May 2018.
- ISBN 978-0-684-82471-0.
- ^ Milam E (2013). "Dunking the Tarzanists. Elaine Morgan and the Aquatic Ape theory". In Oren Harman, Michael R Dietrich (eds.). Outsider Scientists. Routes to Innovation in Biology. University of Chicago Press.
- S2CID 36046030.
- ^ Tobias PV. Foreword: Evolution, Encephalization, Environment. p. viii. in Cunnane & Stewart 2010, pp. vii–xii
- ^ Tobias PV (1998). "Water and Human Evolution". Dispatches Human Evolution. Retrieved 16 January 2017.
- PMID 23272598.
- ^ Morgan 2008, p. 12.
- ^ Morgan 2008, p. 15.
- ^ ISSN 0261-3077. Retrieved 2 May 2017.
- PMID 19853850.
- PMID 24907372.
- ISSN 0261-3077. Retrieved 16 March 2017.
- PMID 20534571.
- S2CID 8544762.
- S2CID 20649815.
- ^ Stringer, Chris; Andrews, Peter (2005). The complete world of human evolution. Thames and Hudson. p. 79.
- ^ Stewart, Kathlyn M. (2010). "The Case For Exploitation Of Wetlands Environments And Foods By Pre-Sapiens Hominins": 137–171.
{{cite journal}}
: Cite journal requires|journal=
(help) in Cunnane & Stewart 2010 - ^ Erlandson JM. "Food for Thought: the Role of Coastlines and Aquatic Resources in Human Evolution".
{{cite journal}}
: Cite journal requires|journal=
(help) - ^ Cunnane & Stewart 2010, pp. 125–136
- ^ Crawford & Marsh 1989, p. 162.
- ^ Crawford & Marsh 1989, p. 159.
- ^ Cunnane & Stewart 2010.
- ^ Stewart, K; Cunnane, S; Tattersall, I, eds. (2014). "Special Issue: The Role of Freshwater and Marine Resources in the Evolution of the Human Diet, Brain and Behavior". Journal of Human Evolution. 77: 1–216.
- ^ Cunnane SC (2005). Survival of the fattest: the key to human brain evolution. World Scientific.
- ^ Cunnane & Stewart 2010, pp. xiii–xvii.
- ^ Broadhurst et al. 2002, pp. 659–660.
- ^ Venturi S, Bégin ME (2010). "Thyroid Hormone, Iodine and Human Brain Development": 112.
{{cite journal}}
: Cite journal requires|journal=
(help) in Cunnane & Stewart 2010, pp. 105–124 - ^ Cunnane & Stewart 2010, p. 47.
- ^ Pond C, Colby D (27 January 1990). "The Driving Force: Food, Evolution and The Future by Michael Crawford and David Marsh". New Scientist (Book review).
- ^ Schagatay, Erika (2014). "Human breath-hold diving ability and the underlying physiology". Human Evolution. 29 (1–3): 125–140.
- .
Bibliography
- Attenborough D (2016). "The Waterside Ape". BBC Radio 4.
- Broadhurst, C. Leigh; Wang, Yiqun; Crawford, Michael A.; Cunnane, Stephen C.; et al. (2002). "Brain-specific lipids from marine, lacustrine, or terrestrial food resources: potential impact on early African Homo sapiens". Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology. 131 (4): 653–673. PMID 11923081.
- Crawford M, Marsh D (1989). The Driving Force. London: Heinemann.
- Cunnane SC, Stewart K, eds. (2010). Human Brain Evolution: The Influence of Freshwater and Marine Food Resources. Wiley. ISBN 978-0-470-60987-3.
- Hardy A (17 March 1960). "Was Man More Aquatic in the Past?". New Scientist. 7 (174): 642–45.[permanent dead link]
- Langdon JH (October 1997). "Umbrella hypotheses and parsimony in human evolution: a critique of the Aquatic Ape Hypothesis". Journal of Human Evolution. 33 (4): 479–94. PMID 9361254.
- Morgan E (1972). The Descent of Woman. London: Souvenir Press. ISBN 978-0-285-63984-3.
- ISBN 978-0-285-62509-9.
- Morgan E (1990). The Scars of Evolution. London: Souvenir Press. ISBN 978-0-19-509431-2.
- Morgan E (1994). The Descent of the Child. London: Souvenir Press.
- Morgan E (1997). The Aquatic Ape Hypothesis. London: Souvenir Press. ISBN 978-0-285-63981-2.
- Morgan E (2008). The Naked Darwinist. Eildon Press. ISBN 978-0-9525620-3-0.
- Roede M, Wind J, Patrick J, Reynolds V, eds. (1991). Aquatic Ape: Fact or Fiction? Proceedings from the Valkenburg Conference. Souvenir Press. ISBN 978-0-285-63033-8.
- Vaneechoutte M, Kuliukas AV, Verhaegen M, eds. (2011). Was Man More Aquatic in the Past? Fifty Years After Alister Hardy - Waterside Hypotheses of Human Evolution. ISBN 978-1-60805-244-8.