An 'Aquatic-ape' stage and a 'Free-sharing floater' stage in human prehistory

Allan Krill


Early humans lived a Hunter-gatherer lifestyle. They must have evolved from apes that lived an Arboreal gatherer lifestyle. But between these two stages in human development, other stages must have gone unrecorded. During those stages, the apes became bipedal waders and runners, and their babies became buoyant swimmers. They lost body fur, lost threatening canine teeth, lost ape strength, and lost estrus signals that all land mammals have. They evolved blubber, a hooded nose, a large brain, a descended larynx, multi-pyramidal kidneys, loud-crying plump babies, and eccrine sweat cooling. Now they were human. They self-domesticated and developed grammatical syntactic language. So why did this all happen, and where did it all happen?

I think the unknown stages can be divided into two: the Aquatic-ape stage and the Free-sharing floater stage. Both stages may have occurred in a Galapagos-like scenario on the volcanic island Bioko, which had huge sea turtles to eat, and no predators to get eaten by. 

I think that about 6 million years ago a few chimpanzee-like apes became trapped on Proto-Bioko. With no forest foods or shelter on that barren island, they lived as Aquatic apes and evolved human features (see Then perhaps 10,000 fully evolved naked humans populated the 200km-long coast of Bioko for 5 million years. These humans freely shared their aquatic habitats, and had no personal properties or territories. They shared their food, because a 300kg turtle provided too much meat for one family. They shared sex because no alpha males could dominate in the water. They shared babies who floated while holding on to the long head hair of mothers, fathers, children, and neighbors. They shared thoughts and feelings using song and language.

I think these obese buoyant humans lived mostly in the water as Free-sharing floaters. They ate shellfish, seaweed, and turtle meat in the water. They sang and talked in the water. They slept in the water, pooped in the water, had sex in the water, gave birth in the water, nursed babies in the water, died in the water, and buried their dead (about 200 deaths each year) respectfully in the water.

These billion or so humans (200 births each year for 5 million years) left no fossils or traces of their existence, because on rainy, warm, and safe Bioko they had no need for tools, weapons, shoes, clothes, or fire. Some Bioko humans, such as Homo erectus, Neanderthals, and Denisovans, went over to mainland Africa relatively early. They invented clothing, tools, and fire, and left fossils in some of the places they lived. But they were not as culturally advanced as the ones who stayed a bit longer on Bioko. When Homo sapiens from Bioko eventually met the less cooperative archaic humans in Africa and Eurasia, they more or less replaced them.


The Island Syndrome

Allan Krill

Remarkable species often evolve on islands, a phenomenon known as "the island syndrome".
The mild climate of an island can explain why humans did not need fur for warmth or sun protection. The lack of large predators on an island can explain why humans could evolve slow and awkward bipedal walking and lose muscle strength. (An average chimpanzee is considerably stronger and can run much faster than any human in the Olympics.) 

Here are the first two paragraphs of the Wikipedia article:  

Island syndrome

From Wikipedia, the free encyclopedia 

Island syndrome describes the differences in morphologyecologyphysiology and behaviour of insular species compared to their continental counterparts. These differences evolve due to the different ecological pressures affecting insular species including a paucity of large predators and herbivores as well as a consistently mild climate.[2]

Ecological driving factors

Island ecosystems cannot support a sufficient biomass of prey in order to accommodate large predators. This largely relieves prey species of the risk of predation,[2] which mostly removes the selection pressure for morphologies, ecologies and behaviours that help to evade large predators. Insular ecosystems tend to comprise large populations of a limited number of species (a state termed density compensation), therefore, they exhibit low biodiversity. This results in reduced interspecific competition and increased intraspecific competition.[2] There is also reduced sexual selection in insular species, which is especially prominent in birds which lose their sexually dimorphic plumage used in sexual displays.[3] Finally, there is reduced parasite diversity in insular ecosystems[4] which reduces the level of selection acting on immune-related genes.


Wikipedia page on AAH, wants you to know it is 'pseudoscience'.

Allan Krill


Aquatic ape hypothesis

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The aquatic ape hypothesis (AAH), also referred to as aquatic ape theory (AAT) or the waterside hypothesis of human evolution, postulates that the ancestors of modern humans took a divergent evolutionary pathway from the other great apes by becoming adapted to a more aquatic habitat.[1]

The hypothesis was initially proposed by the 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 sea shore and sea bed, leading to adaptations that explained distinctive characteristics of modern humans such as functional hairlessness and bipedalism.[2] Elaine Morgan's 1990 book on the hypothesis, Scars of Evolution, received some favorable reviews but was subject to criticism from the anthropologist John Langdon in 1997, who characterized it as an "umbrella hypothesis" with inconsistencies that were unresolved and a claim to parsimony that was false.[3]

The hypothesis is highly controversial, and has been criticized as pseudoscience.[4][5] The hypothesis is thought to be more popular with the lay public than with scientists; in the scientific literature, it is generally ignored by anthropologists.[6][4]


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In 1942 the German pathologist Max Westenhöfer (1871–1957) discussed various human characteristics (hairlessnesssubcutaneous fat, the regression of the olfactory organwebbed fingers, direction of the body hair etc.) that could have derived from an aquatic past, quoting several other authors who had made similar speculations. As he did not believe human beings were apes, he believed this might have been during the Cretaceous, contrary to what is possible given the geologic and evolutionary biology evidence available at the time.[7] He stated: "The postulation of an aquatic mode of life during an early stage of human evolution is a tenable hypothesis, for which further inquiry may produce additional supporting evidence."[8] He later abandoned the concept.[9]

Independently of Westenhöfer's writings, the marine biologist Alister Hardy had since 1930 also hypothesized that humans may have had ancestors more aquatic than previously imagined, although his work, unlike Westenhöfer's, was rooted in the Darwinian consensus. On the advice of his colleagues, Hardy delayed presenting the hypothesis for approximately thirty years.[10][11] After he had become a respected academic and knighted for contributions to marine biology, Hardy finally voiced his thoughts in a speech to the British Sub-Aqua Club in Brighton on 5 March 1960. Several national newspapers reported sensational presentations of Hardy's ideas, which he countered by explaining them more fully in an article in New Scientist on 17 March 1960: "My thesis is that a branch of this primitive ape-stock was forced by competition from life in the trees to feed on the sea-shores and to hunt for food, shellfishsea-urchins etc., in the shallow waters off the coast."[11]

The idea was generally ignored by the scientific community after the article was published. Some interest was received, notably from the geographer Carl Sauer whose views on the role of the seashore in human evolution[12] "stimulated tremendous progress in the study of coastal and aquatic adaptations" inside marine archaeology.[13] In 1967, the hypothesis was mentioned in The Naked Ape, a popular book by the zoologist Desmond Morris, who reduced Hardy's phrase "more aquatic ape-like ancestors" to the bare "aquatic ape", commenting that "despite its most appealing indirect evidence, the aquatic theory lacks solid support".[14]

While traditional descriptions of 'savage' existence identified three common sources of sustenance: gathering of fruit and nuts, fishing, and hunting,[15] in the 1950s, the anthropologist Raymond Dart focused on hunting and gathering as the likely organizing concept of human society in prehistory,[16] 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,"[17] 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.[18][19]

The Hardy/Morgan hypothesis[edit]

Hardy's hypothesis as outlined in the New Scientist was:

My thesis is that a branch of this primitive ape-stock was forced by competition from life in the trees to feed on the sea-shores and to hunt for food, shell fishsea-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.[2]

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 whales and hippopotamuses,[20][21] and noted the layer of subcutaneous fat humans have that Hardy believed other apes lacked, although it has been shown that captive apes with ample access to food have levels of subcutaneous fat similar to humans.[22][23] Additional features cited by Hardy include the location of the trachea in the throat rather than the nasal cavity, the human propensity for front-facing copulationtears and eccrine sweating, though these claimed pieces of evidence have alternative evolutionary adaptationist explanations that do not invoke an aquatic context.[24] Hardy additionally posited that bipedalism evolved first as an aid to wading before becoming the usual means of human locomotion,[25][26] and tool use evolved out of the use of rocks to crack open shellfish.[25][22] 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.[27]


Aquatic Ape Conference delegates in Valkenburg, 1987

The AAH is generally ignored by anthropologists, although it has a following outside academia and has received celebrity endorsement, for example from David Attenborough.[6]

Academics who have commented on the aquatic ape hypothesis include categorical opponents (generally members of the community of academic anthropology) who reject almost all of the claims related to the hypothesis. Other academics have argued that the rejection of Hardy and Morgan is partially unfair given that other explanations which suffer from similar problems are not so strongly opposed. A conference devoted to the subject was held at ValkenburgNetherlands, in 1987. Its 22 participants included academic proponents and opponents of the hypothesis and several neutral observers headed by the anthropologist Vernon Reynolds of the University of Oxford. His summary at the end was:

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.[28]


The AAH is not accepted as empirically supported by the scholarly community,[29][30][31] and has been met with significant skepticism.[32] The Nature editor and paleontologist Henry Gee has argued that the hypothesis has equivalent merit to creationism, and should be similarly dismissed.[33]

In a 1997 critique, anthropologist John Langdon considered the AAH under the heading of an "umbrella hypothesis" and argued that the difficulty of ever disproving such a thing meant that although the idea has the appearance of being a parsimonious explanation, it actually was no more powerful an explanation than the null hypothesis that human evolution is not particularly guided by interaction with bodies of water. Langdon argued that however popular the idea was with the public, the "umbrella" nature of the idea means that it cannot serve as a proper scientific hypothesis. Langdon also objected to Morgan's blanket opposition to the "savannah hypothesis" which he took to be the "collective discipline of paleoanthropology". He observed that some anthropologists had regarded the idea as not worth the trouble of a rebuttal. In addition, the evidence cited by AAH proponents mostly concerned developments in soft tissue anatomy and physiology, whilst paleoanthropologists rarely speculated on evolutionary development of anatomy beyond the musculoskeletal system and brain size as revealed in fossils. After a brief description of the issues under 26 different headings, he produced a summary critique of these with mainly negative judgments. His main conclusion was that the AAH was unlikely ever to be disproved on the basis of comparative anatomy, and that the one body of data that could potentially disprove it was the fossil record.[3]

Anthropologist John D. Hawks wrote that it is fair to categorize the AAH as pseudoscience because of the social factors that inform it, particularly the personality-led nature of the hypothesis and the unscientific approach of its adherents.[5] 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.[34]

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".[35]

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."[36]

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[37] on "The Role of Freshwater and Marine Resources in the Evolution of the Human Diet, Brain and Behavior".[38] 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".[39][40]

Philosopher Daniel Dennett, in his discussion of evolutionary philosophy,[41] commented "During the last few years, when I have found myself in the company of distinguished biologists, evolutionary theorists, paleoanthropologists and other experts, I have often asked them to tell me, please, exactly why Elaine Morgan must be wrong about the aquatic theory. I haven’t yet had a reply worth mentioning, aside from those who admit, with a twinkle in their eyes, that they have also wondered the same thing." He challenged both Elaine Morgan and the scientific establishment in that "Both sides are indulging in adapt[at]ionist Just So stories". Along the same lines, historian Erika Lorraine Milam noted that independent of Morgan's work, certain standard explanations of human development in paleoanthropology have been roundly criticized for lacking evidence, while being based on sexist assumptions.[42] Anatomy lecturer Bruce Charlton gave Morgan's book Scars of Evolution an enthusiastic review in the British Medical Journal in 1991, calling it "exceptionally well written" and "a good piece of science".[43]

In 1995, paleoanthropologist Phillip Tobias declared that the savannah hypothesis was dead, because the open conditions did not exist when humanity's precursors stood upright and that therefore the conclusions of the Valkenberg conference were no longer valid. Tobias praised Morgan's book Scars of Evolution as a "remarkable book", though he said that he did not agree with all of it.[44][45] Tobias and his student further criticised the orthodox hypothesis by arguing that the coming out of the forest of man's precursors had been an unexamined assumption of evolution since the days of Lamarck, and followed by Darwin, Wallace and Haeckel, well before Raymond Dart used it.[4]

Reactions of Hardy and Morgan[edit]

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.[46] As he later said to his ex-pupil Desmond Morris, "Of course I then had to write an article to refute this saying no this is just a guess, a rough hypothesis, this isn't a proven fact. And of course we're not related to dolphins."[38]

Elaine Morgan's 1972 book Descent of Woman became an international best-seller, a Book of the Month selection in the United States and was translated into ten languages.[47] The book was praised for its feminism but paleoanthropologists were disappointed with its promotions of the AAH.[48] Morgan removed the feminist critique and left her AAH ideas intact, publishing the book as The Aquatic Ape 10 years later, but it did not garner any more positive reaction from scientists.[48]

Related academic and independent research[edit]

Although the general reaction to Hardy and Morgan's proposals was silence by the relevant academic community, there have been over the last decades some academics who were inspired by AAH proposals, even to the point of pursuing particular lines of research on its basis. Some of the academics and professional scientists who have supported the AAH include Michael Crawford, Professor and Director of the Institute of Brain Chemistry and Human Nutrition at Imperial College London, his former postdoctoral researcher, Stephen Cunnane, now professor of medicine at Université de Sherbrooke, Erika Schagatay, professor of Environmental Physiology at Mid Sweden University, Kathlyn M. Stewart, Section Head of Palaeobiology at the Canadian Museum of Nature, and Tom Brenna, Professor of Paediatrics and Chemistry at University of Texas.

Wading and bipedalism[edit]

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[49] and is still practical in thigh-high water.[50]

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.[51]


Neanderthal skull (right) compared with modern human

Evidence supports aquatic food consumption in Homo as early as the Pliocene,[52] but its linkage to brain evolution remains controversial.[53][54] Further, there is no evidence that humans ate fish in significant amounts earlier than tens to hundreds of thousands of years ago.[55] Supporters argue that the avoidance of taphonomic bias is the problem, as most hominin fossils occur in lake-side environments, and the presence of fish remains is therefore not proof of fish consumption.[56] They also claim that the archaeological record of human fishing and coastal settlement is fundamentally deficient due to postglacial sea level rise.[57][58]

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:[59]

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.[60] Cunnane, Stewart, Crawford, and colleagues published works arguing a correlation between aquatic diet and human brain evolution in their "shore-based diet scenario",[61][62][63] acknowledging the Hardy/Morgan's thesis as a foundation work of their model.[64] As evidence, they describe health problems in landlocked communities, such as cretinism in the Alps and goitre in parts of Africa due to salt-derived iodine deficiency,[65][66] and state that inland habitats cannot naturally meet human iodide requirements.[67]

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."[68] 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.[35]

Diving behavior and performance[edit]

Aside from working as a professor, Erika Schagatay is also an experienced scuba and freediver whose research centers around human diving abilities. 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.[69] John Langdon suggested that such traits could be enabled by a human developmental plasticity.[70]

Vernix caseosa[edit]

Tom Brenna, professor of pediatrics whose primary research focuses on fats, oils, and fatty acids,[71] listened to the 2005 radio documentary Scars of Evolution where David Attenborough reported an observation that harbor seals were born with something that resembled human vernix caseosa.[72] Intrigued, Brenna led a team that collaborated with Judy St Leger at San Diego Seaworld to compare the chemistry of human vernix and samples from California sea lion pups. They established that the molecular composition of both is similar, being rich in branched chain fatty acids and squalene.[73]

Bioko island postulated to be the aquatic location[edit]

Bizarre creatures sometimes evolve on islands, a phenomenon known as the island syndrome. Geology professor Allan Krill recently suggested[74] that humans evolved by peripatric speciation on a barren volcanic island, in a scenario similar to that of the Galapagos Marine iguana. The chimpanzee-human last common ancestor may have accidentally rafted to proto-Bioko island of western Africa. As with the iguana, these arboreal animals may have been stranded with no forest foods, and their exclusively marine diet and semiaquatic habitat resulted in unique anatomical changes. Bioko has a rainy climate with neither strong sun nor cold nights, so body fur would not be as necessary there. Bioko has no large predators, so primates evolving into vulnerable humans could survive there without inventing weapons. Beaches on Bioko are visited by many sea turtles each night during much of the year, so turtle eggs and meat could have been shared by semiaquatic humans without tools or fire. Plentiful marine food may have supported large coastal populations, as with the marine iguana. Dense habitation may have led to self-domestication and Proto-Human language. Some hominins may have left Bioko and invented clothing, tools, and fire, that were necessary elsewhere. Because the warm humid climate of western Africa causes bones to decay rapidly, no mammal fossils have ever been reported from Bioko or any areas inhabited by chimpanzees or gorillas. Therefore there is no fossil evidence for chimpanzee or gorilla evolution, or for an early human presence on Bioko. If there was an average population of 10,000 semiaquatic humans on Bioko for 5 million years, this would be one billion people. The corpses of the 200 people who would have died each year could have been buried respectfully in the sea. Genetics might be able to test the Bioko hypothesis. Complementing the recent African origin of modern humans it seems possible that Neanderthals and early modern humans came directly from Bioko while it was connected to the mainland by a Pleistocene land bridge.

See also[edit]


  1. ^ Rhys-Evans P (2019). The Waterside Ape: An Alternative Account of Human Evolution. CRC Press. pp. 7–9. ISBN 978-0-367-14548-4.
  2. Jump up to:a b Hardy 1960
  3. Jump up to:a b Langdon 1997.
  4. Jump up to:a b c Bender R, Tobias PV, Bender N (2012). "The Savannah hypotheses: origin, reception and impact on paleoanthropology". History and Philosophy of the Life Sciences34 (1–2): 147–84. PMID 23272598.
  5. Jump up to:a b Hawks JD (4 August 2009). "Why anthropologists don't accept the Aquatic Ape Theory" (Blog post).
  6. Jump up to:a b Rae TC, Koppe T (2014). "Sinuses and flotation: does the aquatic ape theory hold water?". Evolutionary Anthropology23(2): 60–4. doi:10.1002/evan.21408PMID 24753346S2CID 5456280most practicing anthropologists are unbothered by the Aquatic Ape Theory (AAT) and its advocates, except perhaps when a student brings it up in lecture
  7. ^ Westenhöfer 1942, p. 148.
  8. ^ 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.
  9. ^ Westenhöfer M (1948). Die Grundlagen meiner Theorie vom Eigenweg des Menschen: Entwicklung, Menschwerdung, Weltanschauung. Heidelberg: Carl Winter. ISBN 978-3-533-01969-5.
  10. ^ Reeve E (1992). "Book review: The Aquatic Ape: Fact or Fiction?"Genetics Research59 (1): 64–66. doi:10.1017/S0016672300030184.
  11. Jump up to:a b Hardy 1960.
  12. ^ Sauer CO (1960). "Seashore–Primitive home of man?". Proceedings of the American Philosophical Society106 (1): 41–7. JSTOR 985209.
  13. ^ Erlandson JM (2001). "The archaeology of aquatic adaptations: paradigms for a new millennium". Journal of Archaeological Research9 (4): 287–350. doi:10.1023/a:1013062712695S2CID 11120840.
  14. ^ Morris D (1967). The Naked Ape. McGraw-Hill. p. 29ISBN 978-0-09-948201-7.
  15. ^ Morgan LH (1877). Ancient Society. New York: Henry Holt & Co. p. 10. Retrieved 29 October 2016.
  16. ^ Dart RA (1953). "The Predatory Transition from Ape to Man"International Anthropological and Linguistic Review1 (4). Retrieved 29 October 2016.
  17. ^ Morgan 1972, p. 11.
  18. ^ Vaneechoutte, Kuliukas & Verhaegen 2011
  19. ^ Rhys-Evans P (2019). The Waterside Ape: An alternative Account of Human Evolution. CRC Press. ISBN 978-0-367-14548-4.
  20. ^ Morgan 1990, pp. 69-79.
  21. ^ Langdon (1997), p. 483
  22. Jump up to:a b Langdon (1997), p. 487
  23. ^ Wood FJ (1929). Man's Place among the Mammals. Longmans, Green & co. p. 309. Retrieved 4 February 2017.
  24. ^ Sterelny K, Fitness J (1 March 2004). From Mating to Mentality: Evaluating Evolutionary Psychology. Psychology Press. p. 250. ISBN 978-1-135-43212-6.
  25. Jump up to:a b Hardy 1960, p. 645.
  26. ^ Langdon (1997), p. 481
  27. ^ Kuliukas AV, Elaine M (2011). Aquatic Scenarios in the Thinking on Human Evolution: What are they and How do they Compare?. pp. 106–119. ISBN 978-1-60805-244-8. Retrieved 4 February 2017.
  28. ^ Reynolds V (1991). Cold and Watery? Hot and Dusty? Our Ancestral Environment and Our Ancestors Themselves: an Overview. p. 340. in RoedeWindPatrickReynolds 1991
  29. ^ Dunsworth, H.M. (2007). Human Origins 101ABC-CLIO. p. 121. ISBN 978-0-313-33673-7.
  30. ^ McNeill D (2000). The Face: A Natural History. Back Bay. pp. 36–37. ISBN 978-0-316-58812-6.
  31. ^ Trauth MH, Maslin MA, Deino AL, Junginger A, Lesoloyia M, Odada EO, et al. (2010). "Human evolution in a variable environment: The amplifier lakes of Eastern Africa" (PDF)Quaternary Science Reviews29 (23–24): 2981–2988. Bibcode:2010QSRv...29.2981Tdoi:10.1016/j.quascirev.2010.07.007.[permanent dead link]
  32. ^ Graham JM, Scadding GK, Bull PD (2008). Pediatric ENTSpringer. p. 27. ISBN 978-3-540-69930-9.
  33. ^ Foley R, Lahr MM (2014). "The role of "the aquatic" in human evolution: constraining the aquatic ape hypothesis". Evolutionary Anthropology23 (2): 56–9. doi:10.1002/evan.21405PMID 24753345S2CID 849419Where 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.
  34. ^ Frazier K (2015). "Quacks and cranks, GMOs and climate, science and philosoph—CFI Conference covers it all"Skeptical Inquirer39 (5): 12. Retrieved 25 February 2017.
  35. Jump up to:a b Gee H (2013). The Accidental Species: Misunderstandings of Human Evolution. U of Chicago Press. p. 115. ISBN 978-0-226-04498-9. Retrieved 6 January 2017.
  36. ^ Foley R, Lahr MM (2014). "The role of "the aquatic" in human evolution: constraining the aquatic ape hypothesis". Evolutionary Anthropology23 (2): 56–9. doi:10.1002/evan.21405PMID 24753345S2CID 849419.
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  48. Jump up to:a b Milam EL (13 May 2013). "Elaine Morgan and the Aquatic Ape"The GuardianISSN 0261-3077. Retrieved 2 May2017.
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Submitted edit of Aquatic Ape Hypothesis page on Wikipedia

Allan Krill

Bioko island postulated to be the aquatic location

Bizarre creatures sometimes evolve on islands, a phenomenon known as the island syndrome. Geology professor Allan Krill recently suggested[74] that humans evolved by peripatric speciation on a barren volcanic island, in a scenario similar to that of the Galapagos Marine iguana. The chimpanzee-human last common ancestor may have accidentally rafted to proto-Bioko island of western Africa. As with the iguana, these arboreal animals may have been stranded with no forest foods, and their exclusively marine diet and semiaquatic habitat resulted in unique anatomical changes. Bioko has a rainy climate with neither strong sun nor cold nights, so body fur would not be as necessary there. Bioko has no large predators, so primates evolving into vulnerable humans could survive there without inventing weapons. Beaches on Bioko are visited by many sea turtles each night during much of the year, so turtle eggs and meat could have been shared by semiaquatic humans without tools or fire. Plentiful marine food may have supported large coastal populations, as with the marine iguana. Dense habitation may have led to self-domestication and Proto-Human language. Some hominins may have left Bioko and invented clothing, tools, and fire, that were necessary elsewhere. Because the warm humid climate of western Africa causes bones to decay rapidly, no mammal fossils have ever been reported from Bioko or any areas inhabited by chimpanzees or gorillas. Therefore there is no fossil evidence for chimpanzee or gorilla evolution, or for an early human presence on Bioko. If there was an average population of 10,000 semiaquatic humans on Bioko for 5 million years, this would be one billion people. The corpses of the 200 people who would have died each year could have been buried respectfully in the sea. Genetics might be able to test the Bioko hypothesis. Complementing the recent African origin of modern humans it seems possible that Neanderthals and early modern humans came directly from Bioko while it was connected to the mainland by a Pleistocene land bridge.

Where, when, & why did humans originate?

Allan Krill

The earliest Y-chromosome DNA (A00) and language (Khoi-San with 'clicks') are in west Africa, from about 200,000 years ago.
But how could anatomically modern humans suddenly start there, having left no fossil record of their earlier history?  
I think humans evolved on Bioko Island in a Galapagos-like scenario.

Chimpanzees live in western Africa where there are no fossils of any mammal, because bones decay too fast. About 6 million years ago, a few chimps accidentally rafted 32 km to the volcanic islands of Proto-Bioko. There were no trees or predators. Their only food was seaweed, shellfish, turtle eggs and turtle meat: hundreds of huge sea-turtles visit the beaches each night to lay eggs.

Those 'aquatic apes' changed during the first million years: they evolved a bald body, blubber, large buoyant brain from marine DHA-fat, human nose, descended larynx and breath control for diving and speech, multipyramidal kidneys for excess salt, and all the other uniquely human traits.  

During the next 5 million years, I envision a population of 10,000 fat naked humans on Bioko. It was an easy life, mostly in the water, singing about turtles, sharing food—self-domesticating. It's rainy on Bioko, warm day and night, year round. They needed no clothes, tools, weapons, or fire.

Some early explorers (e.g. 'Homo Erectus', 'Neanderthals', and others) swam to the mainland. Most stayed on Bioko until about 200,000 years ago, when they used a Pleistocene land bridge to walk over. They invented clothes, weapons, and fire, needed to survive in all other environments.  

Allan Krill, Ph.D.
        Read Krill's Anthropogeny blog for details.        See also   

Mitochondrial DNA (maternal lineage) seems to point to western and central Africa

Allan Krill

As I posted last week, Y-DNA (paternal lineage, Haplogroup A00) seems to point to western Africa, near Bioko.

Mitochondrial DNA (maternal lineage, Haplogroup L1) seems to point to more or less the same part of Africa:

Human expansion: Bioko --> west Africa --> all parts of planet Earth.
(With the large brain, evolved due to marine DHA, Homo sapiens could go anywhere.)

An estimated 10,000 Homo sapiens might have lived on Bioko Island for 5 My

Allan Krill

Many female sea-turtles come to the Bioko beaches each night during much of the year, to bury their eggs in the sand (Butynski 1996Tomas 1999). The turtles return immediately to the sea, leaving the eggs unguarded. The eggs are about the size of hen's eggs, and there are about 100 eggs in a typical nest. 

There are several species of sea-turtle that lay eggs on Bioko. They are huge animals, weighing several hundred kilos each. As recently as 1990, about 10 sea-turtles were being caught each night, and the meat transported by boat to city markets for sale. That corresponds to over a kilogram of meat daily for 1,000 people. Local people told researchers that in the 1940s, as many as 100 turtles were taken each night. The turtles are only taken along the 19 km of beaches on the southern side of Bioko (see the map), where there are no roads. Other beaches of the island are more accessible, and sea-turtle eggs there were overexploited in previous times, so that few if any turtles visit those beaches now. 

I think that these sea-turtles were important in human evolution. In my version of the aquatic ape hypothesis (Krill 2020) a few chimpanzees became trapped on Bioko, and their descendants evolved all the human traits. Those semiaquatic humans could have lived largely on sea-turtle meat, supplemented by shellfish and seaweed. Turtles are easy to kill without weapons, and the meat can be shared and eaten raw without tools or fire. If the Bioko humans were careful not to overexploit eggs, they could have taken as many full grown sea-turtles as they needed. 

There could have been a stable population of 10,000 semiaquatic humans on Bioko. This estimate is based on the 34 km of suitable beaches on Bioko (as mentioned in Butynski 1996), and an average of 300 humans per kilometer of beach. This estimate is obviously only a guess. At times there could have been many fewer, or many more. By being spread around the 200 km long coastline of Bioko, the semiaquatic human population would have been robust for millions of years, able to survive local viruses and volcanic eruptions. 

If my estimate of 10,000 semiaquatic humans seems high, consider the population densities of the emperor penguin on Antarctica, or the marine iguana on Galapagos. They also get their food from the sea. There are about 300,000 marine iguanas living along the Galapagos shorelines, with as many as 8,000 per linear kilometer (Wikipedia). Like the postulated chimpanzees on Bioko, the originally arboreal iguana became trapped on a volcanic island with no large predators and no terrestrial foods, and they were forced into a semiaquatic lifestyle. 

Based on molecular clocks, it is thought that human and chimpanzee lineages diverged about 6 my ago. If the founding chimpanzees became trapped on Proto-Bioko at that time, it might have taken a million years for them to evolve human traits and become modern Homo sapiens. After that, a stable population of 10,000 of these semiaquatic humans may have existed on Bioko coasts for 5 My, without needing to invent fire, weapons, clothing, or tools, and without leaving a fossil record. They would have spent the days in the water, singing and talking. They could have taught their children to respect turtle eggs and help turtle hatchlings reach the sea safely (something that sea-turtle mothers do not do.) 

Some humans may have left Bioko early. But unaware that large predators existed on the mainland, and having no weapons, few of them would have survived the first week away from Bioko. As recently as 200,000 years ago, most of the humans on Earth may have been living in the sea on Bioko.  

Butynski 1996:

Tomas 1999:

World Map of Y-DNA Haplogroups

Allan Krill

I had no idea where in Africa geneticists thought 'Y-Chromosomal Adam' was from, but obviously I was pleased to discover this MAP of haplogroups and languages. It includes the recognition of Haplogroup A00, which was first published in 2013. I would call A00 reliable evidence, in contrast to one-time fossils finds, which may be false. More A00 genetic evidence has been independently determined by others since 2013.

This map is especially nice, because it shows languages and is not cluttered up with age estimates.

Old age estimates of A00 in the 2013 article were corrected by competitors in a publication in 2014. This type of correction is not usually possible with fossil interpretations, because competitors are not allowed access to the fossils or fossil locations.

The Khoisan people, who have a high frequency of Haplogroup A2,A3, also have genes that promote a unique amount of blubber ( which would be of value to aquatic apes, and not especially useful for terrestrial or arboreal ones. 

Khoisan people also have
 genes for elongated labia (female genitalia) that might have somehow helped women living in water avoid infections. 

Khoisan are thought to have the world's oldest language. It is characterized by click-sounds. 
Maybe aquatic humans on Bioko spent most of their time singing and click-talking in the water.  

I think chimpanzees became isolated on Proto-Bioko 6 my ago. After only one generation they were probably bipedal and pretty good swimmers. Evolution would go fast due to the extreme aquatic selection pressures. Most babies would likely drown soon after birth, and a new baby, maybe wth more human-like features (such as better nose and more blubber) could be born quickly to the same mother. After 100 generations (2000 years) the semiaquatic Bioko-apes would be so evolved that no one would call them 'chimpanzees'. After a million years, they were probably fully human (semiaquatic.) But we have no fossils of them. And any humans that left the island during the first few million years were quickly killed by predators.

If Khoisan have been on their continent for the past 200,000 years and North Americans have been on their continent for the past 20,000 years, that difference is trivial compared to the 5,000,000 years of humans in the water on Bioko. But Khoisan (in their genes, anatomy, physiology, and language) would be closer to the semiaquatic humans than North Americans are. So in my opinion, no living humans are significantly closer to chimpanzees. 


Aquatic humans on Bioko Island presumably had neutral-colored skin

Allan Krill

In the Bioko model of human evolution, human skin evolved from neutral-colored chimpanzee skin. The aquatic apes lost their fur and evolved into naked humans, because they were mostly in the water, at least during daylight hours. Water covered most of their bodies, and hair covered the tops of their heads.

Humans with neutral-colored skin presumably left Bioko during the last 300,000 years, when there were 3 or 4 periods of land bridges. The last humans may have left as recently as 50,000 years ago. They quickly invented clothing for protection during the day and warmth at night, but there was still some skin exposed to the elements. Their skin colors evolved according to where they migrated.

Lighter skin was selected for in Europe and Asia, because it helped convert the UV of sunlight to vitamin D. Darker skin was selected for in sunny African climates, because it helped protect against too much UV, which causes skin cancer.

Here is a map of the world showing UV levels. Note that the African coast in the Gulf of Guinea is relatively light, because it is often cloudy there. Bioko itself is not shown on this map, but it would probably be one of the lightest colors, because it has its own landscape and climate. Wikipedia: Bioko has a rather debilitating climate. The so-called dry season lasts from November to March, and the rest of the year is rainy. The average annual temperature of about 77 °F (25 °C) varies little throughout the year. Afternoon temperatures reach the high 80s °F (low 30s °C) and drop to only about 70 °F (21.1 °C) at night. Most of the time the sky is cloudy and overcast.

How early might apes have rafted to Proto-Bioko ?

Allan Krill

We don't know how old Bioko Island actually is, or when the ancestors of humans might have rafted there.

The oldest known rocks on the surface of Bioko are about 1 million years old (see Figures 1 and 3 from Fitton). But rocks at deeper levels are certainly older (see the cross section of a typical volcano, with some possible age numbers added). Bioko may be as old as its volcanic neighbors Oku (at least 23 Myr old) and Principe (at least 30 Myr old). (See the paper by J. G. Fitton, 1987).

Viruses, parasites, and their DNA vary from place to place. We will eventually be able to use the absence of 'African' DNA in living humans to know if and when human ancestors were not in Africa. (Negative evidence.) We will also be able to use DNA in living humans to determine where human ancestors actually were during different times (Positive evidence.) An isolated island like Bioko (during times with no land bridge) would have endemic parasites and viruses that might be identifiable in modern humans' DNA.


Is Bioko Island on 'The Wrong Side of Africa'?

Allan Krill

It depends if you are interested in where apes and humans could easily survive, or where bones and fossils could easily survive.

All African apes live in the green rainforest areas. Billions of mammals have lived or evolved in those rainforest areas, but not a single ape or mammal fossil has ever been found there. Bones decay quickly in those areas, so they do not become fossils.

If your career is to find and publish fossils, you can ignore the green areas. But if you want to understand apes and humans and their evolution, I think you should focus on the genetics (not the fossils) of apes and humans. 

(Bioko is an exotic volcanic island in the green rainforest area.)

Maps from Jonathan Kingdon (2013): Mammals of Africa, Bloomsbury Publ., 3763 p.

Out of Bioko theory of human evolution

Allan Krill

Out of Bioko theory (OOB) is not the same as Out of Africa theory (OOA). In the following summary, ages and other details are debatable (obviously).

8 Myr. Chimpanzees and gorillas split from a common knuckle-walking ape ancestor in western-central Africa. The split occurred because gorillas chose low quality foods that were always available. They evolved a larger body. Chimpanzees chose higher quality foods that required more searching and more tree climbing.
6 Myr. A few chimpanzees became trapped on a tree floating in an African river, and rafted out to the Atlantic Ocean. They stranded on Proto-Bioko, an evolving group of barren volcanic islands. They couldn't escape. The chimps survived by eating crabs and seaweed, and eventually learned to swim. They lived mostly in the sea, which provided all of their food. They walked upright in neck-deep water. The jagged volcanic rocks of the island were uncomfortable to walk or sleep on, so the chimpanzees' descendants slept on beaches or nests of floating seaweed. There were no large predators on Bioko (also none today). There were no African parasites or viruses on Bioko, which explains why human DNA is somewhat non-African. It was always warm and nearly always cloudy or rainy on Bioko (as today), so hair was not needed for warmth or sun protection. The Bioko semiaquatic apes evolved bald bodies, subcutaneous fat (blubber) for buoyancy and insulation, descended-larynx and voluntary breath control for mouth-breathing and diving, and all other unique human features. The apes eventually discovered that they could live comfortably on sea-turtle eggs and sea-turtle meat (also available today in immense quantities on Bioko beaches), supplemented by seaweed and shellfish. Because of abundant food with little effort, there were thousands of these fat floating apes along the 200 km-long coastline of Bioko (not unlike the 200,000 marine-iguanas that currently live along the shores of Galapagos islands). The large population remained stable for millions of years, while humans evolved their unique anatomical features, language, concealed-estrus, frontal sex with unreliable female orgasms, and self-domesticated culture.
4 Myr. Some bipedal small-brained Bioko apes swam to mainland Africa, where some hybridized with gorillas and chimpanzees. Their various descendants wandered to drier parts of Africa, where they left Australopithecus-fossils.
2 Myr. Some chimpanzees (Pan troglodytes) of central Africa became isolated on the south side of the Congo River and evolved into the bonobo (Pan paniscus), due to genetic drift. Because of similar habitats, there were no strong selection pressures to promote rapid evolution.
2 Myr. Chimpanzees were isolated by major rivers in central and western Africa, and evolved into the four modern subspecies of chimpanzee (no strong selection pressures). Similarly, isolated gorillas evolved into the four modern subspecies of gorilla (no strong selection pressures). 
1.5 Myr. By this time, humans on Bioko had evolved large brains (which consist mostly of DHA-rich fat), as a result of the DHA-rich marine diet and the selection pressure for general fat-accumulation. Some large-brained humans walked to mainland Africa during geological periods of low sea level (during glaciations of the northern continents). To compensate for their pathetically weak, unprotected, and slow-running bodies, they used their large brains to invent clothing, shoes, tools, and weapons, which were needed to deal with harsh sun and dangerous predators. They migrated to places where Homo erectus fossils have been found (East Africa, Europe, Java, China.)
0.8 Myr. Some humans left Bioko, invented clothes and weapons, and migrated to places where Neanderthal and Denisovan fossils have been found.
0.3 Myr. Some humans left Bioko, invented clothes and weapons, and migrated to places where Homo sapiens fossils have been found. 
0.05 Myr. The last humans left Bioko only about 50,000 years ago. They invented clothes and weapons, and spread out to all the continents. Those who went north evolved lighter skin that could absorb vitamin D. Others evolved darker skin that shielded against ultraviolet rays. (Chimps have intermediate-colored skin, as seen best in hairless chimps that have alopecia). Neanderthals, Denisovans, and all races of Homo sapiens are the same species, with some genetic and phenotypic differences. Semiaquatic humans were wiped out by terrestrial humans who returned to Bioko while it was connected to the mainland during the most recent period of low sea level (c. 70,000-10,000 years ago.) The returning humans had developed their foreign language, culture, and religion in mainland Africa, and using their weapons, they carried out the world's first genocide on Bioko. 

According to this hypothesis, all humans and prehumans are "Out of Bioko" but it is misleading to say "Out of Africa".

Beware of parsimony

Allan Krill

Beware of parsimony: it can kill a wonderful adventure story — reducing it to a single sentence. 

For example: Some chimps got isolated in an aquatic habitat on a barren volcanic island, and a few descendants escaped to leave early fossils, while others evolved further into humans, before spreading out around the world.

That simple model can explain all the evidence: human anatomy, physiology, paleontology, genetics, psychology (self-domestication), history. No one likes it, because it would kill many good adventure stories and many good careers.

Densely populated aquatic humans on Bioko would evolve and self domesticate

Allan Krill

AAT message #70636   Thanks for discussing perceived problems with Bioko. It helps me to consider these things.


The aquatic humans didn't have boats, so I'm not sure that a wide continental shelf would have been important. I think what is important that the aquatic habitat stayed unchanged and the food supply stayed reliable for the last few million years, while the sea level was rising and falling by as much as 120 meters. 


The southwest side of Bioko currently has beaches with a steady supply of huge sea-turtles and turtle eggs. The sand on beaches typically stays in the surf zone, moving up and down as sea levels rise and fall over geologic time. The aquatic humans did not need much space. They could have been packed densely along the shoreline, like Emperor penguins, or Crabeater seals (there maybe 75 million of them!), or the Marine iguanas of Galapagos. 


This is how densely the Marine iguanas can live: 

On some shorelines they can be very numerous, with densities as high as 8,000 per kilometer, and their biomass compared to the area they occupy may surpass that of any known reptile. However, their distribution is patchy, and colonies are generally found within 100 m of the ocean, naturally limiting their range. The total population for the entire archipelago is estimated to be 200,000–300,000 individuals 


With this kind of dense population and fat easy living on Bioko, the aquatic humans would self-domesticate. They would develop language and civilized behavior. They would share genes and evolve aquatic traits together, unlike clusters of undomesticated humans or hunter-gatherers spread around several continents.


Here is a map to show Bioko the last time it had a land bridge (from about 70,000 to 10,000 years ago). I think the last 'aquatic apes' (fully evolved Homo sapiens) may have left Bioko only about 50,000 years ago.

Anthropogeny. Inferring a two-step origin of the naked ape

Allan Krill

Manuscript in preparation. April 10, 2021

Out of Africa: origins and evolution of human malaria parasites

Allan Krill

Humans apparently first got malaria parasites by being bitten by mosquitos that had also bitten western gorillas.
Loy et al. 2017.
Out of Africa: origins and evolution of the human malaria parasites Plasmodium falciparum and Plasmodium vivax

That species of gorilla is nearest to the island of Bioko. Using DNA of parasites, viruses, etc., the origin of humans on Bioko is a testable hypothesis, not an unprovable model. When geneticists become aware of this hypothesis, they will begin actively testing it. 

Here is an interesting paragraph from that paper: 

Whilst it could be argued that the ape P. vivax was brought to Africa by humans who migrated from Asia (Prugnolle et al., 2013), this hypothesis has been refuted by sequences indicating the existence of a related, but distinct, Plasmodium sp. that also infects African apes. This Plasmodium sp. which is apparent in trees of mt, nuclear and apicoplast sequences (Fig. 4), has been found in chimpanzees from two different locations in Cameroon (the BQ and DG field sites in Fig. 2) and represents the closest known relative of P. vivax. The most parsimonious interpretation of this finding is that the common ancestor of these two species was in Africa, indicating that the lineage existed there for a long time before P. vivax arose as a distinct species (Fig. 4). We propose to designate this newly described species Plasmodium carteri, in honour of Richard Carter, who has long championed the hypothesis that P. vivax originated in Africa (Carter, 2003; Culleton and Carter, 2012).

Parsimony is popular among geneticists, unpopular among paleoanthropologists

Allan Krill

The parsimony principle is basic to all science and tells us to choose the simplest scientific explanation that fits the evidence. In terms of tree-building, that means that, all other things being equal, the best hypothesis is the one that requires the fewest evolutionary changes.

It seems to me that paleoanthropologists do not prioritize parsimony, because complicated models help them to publish more scientific papers based on their paltry fossil evidence. They are trying to make complicated stories from minimal evidence. Their evidence is irreproducible and untestable by impartial scientists. Geneticists are looking for parsimony, because their evidence is so vast. They are trying to make simple stories, from a huge amount of evidence. Their models are mathematical and can be recalculated. If their models are not parsimonious, competitors will produce better, more parsimonious models. 

Here is a paper from 2013 that I just came across a few days ago, by Prado-Martinez et al. Great ape genetic diversity and population history

A parsimonious explanation is that orangutans, gorillas, and chimpanzees evolved and speciated just where we find them today (my additions to the chart in red). A parsimonious model is that humans are simply another species of Pan, that evolved within the same range as the modern chimpanzees, before humans began to make tools, weapons, clothes, and shoes, and wander into other ranges and habitats. As humans wandered beyond their site of speciation, they left some fossils in various places, but those fossils do not indicate where they actually evolved. 

The Passionate Ape, 2001 by Craig Hagstrom (pdf version)

Allan Krill

This is a brilliant book. Free pdf download here:

The Passionate Ape. Bad Sex. Strong Love, and Human Evolution
. by Craig Hagstrom.
Starting from the Aquatic Ape hypothesis, this work outlines the selective pressures and processes which could move an ape from land to an aquatic life and back.  Using primate morphology, it shows why apes make poor aquatics that are prime candidates to return to land when conditions permit.

It uses Great Ape behavioral traits to describe the mental constraints on such evolutionary moves, and to show how the land-water-land transition would in turn shape our mental evolution.  The major focus is on mating issues and sexual dysfunctions caused by these transitions, and how our coping mechanisms became vital assets setting us apart from the other Great Apes.

The past 12 months of Krill's messages at

Allan Krill

I have learned a lot from reading and writing messages with the AAT (aquatic ape theory) group
I hope to get a group discussion going here some day at

A volcanic-island model for the origin of the seal and other marine mammals

Allan Krill

From genetic evidence it is thought that the first seals evolved about 23 million years ago, near the beginning of the Miocene epoch. A simple model for the evolution of seals is that mammals resembling dogs, bears, and weasels accidentally rafted to oceanic volcanic islands that eventually sank out of sight. 

Erosion acts on rocks that are exposed above sea level. After the last active volcano of an oceanic island becomes extinct, erosion can remove the mountain and reduce it to a low flat-topped island. Erosion mostly stops at sea-level, but subsidence continues. Cooling and contraction of the mantle beneath the ocean floor cause oceanic islands to sink a thousand or more meters over a time span of tens of millions of years. A flat-topped undersea mountain is called a guyot, and there are 283 known guyots in the world's oceans. 

Considering the models for the Galapagos marine iguana, and for Bioko chimps, this model of sinking oceanic volcanic islands seems likely for seals, and for other aquatic mammals. But I have not found mention of such models on the internet.