For a Living Ocean

Aquatic Ape Theory

The Aquatic Ape Theory (AAT) was formulated by Alister Hardy in year 1960. The theory attempts to answer a lot of unanswered questions that have plagued mankind about our heritage – why do we walk on two legs? why are we naked? why do we sweat? How come that babies automatically hold their breath under water? etc. Hardy suggested that we during the evolution have spent a considerable time on the coastlines and adapted to a semi-aquatic environment, not on the hot dry savannah or in the forest with the other primates.

OLYMPUS DIGITAL CAMERAAll from the beginning the theory has been criticized, ridiculed, ignored and a source of strong feelings in the anthropological community. But why is the Aquatic Ape Theory  so controversial and  differently understood by scientists? This is what I tried to find out in my Bachelor Thesis (2008) about the Aquatic Ape Theory at Lund University. After interviews with scientists and after reading of anthropological books, I have tried to show that the aquatic ape-coldness depends on its challenging nature against the anthropological paradigm, which describes human beings as creative and hunting creatures who can live in any environment. The Aquatic Ape theory – on the other hand – picks out one of all these environments and says: “here has our evolution occurred: we have been aquatic apes”. Due to this, the theory has become an anomaly; it has been ignored, eliminated and stigmatized.

I can see two possible future scenarios for the Aquatic Ape Theory. The first scenario is that the old anthropological paradigm continues to be intact, and then is the aquatic ape doomed to remain anonymous. The other scenario is that someone formulates a completely new paradigm where human beings are seen as environmental specialists rather than environmental generalists. Only then will the Aquatic Ape Theory get an essential role in the explanation of human evolution.

Alteration of the Waterside Theory

Initially, Alister Hardy and Elaine Morgan suggested that human ancestors had been living along the coast along during a limited period of time 5-7 million years ago, and then left for land. But today many aquatic ape proponents believe that our human ancestors continued to live close to water. One of the proponents, Dr. Marc Verhaegen, suggests that Homo Erectus (living 1,9 million to 70 000 years ago) were shallow water divers migrating along coasts and rivers. It is also beleived that the island of Flores was inhabited 1 million years ago (situated 18km from nearest island) and later evolved into what we now know as Homo Florensis that died out between 17,000 and 12,000 years ago. However, it has been suggested that even earlier predecessors, as Homo habilis or even Australopithecus, have given rise to the “Hobbit man”. It is also known that the first specimen of Homo Sapiens were living predominantly in an marine environment.

Hence, today’s proponents of the aquatic ape theory argue that human beings were living along oceans/rivers/lakes much longer than previously expected. This is a positive development for the theory, making it more falsifiable. But the main problem is still intact: present-day humans are still seen as environmental generalists.

The history of human evolutionary history is written on our bodies, not mainly in old fossils. We have to accept the idea that human beings are biologically and physiologically adapted to live in a certatin habitat, just like other species. Of course, babies give us the best clue to our evolutionary history – because they are shaped by heredity, not environment, and they are, indeed, aquatic creatures.

You can read my thesis on The Aquatic Ape Theory here: Vattenapeteorin – Paradigmskifte eller pseudovetenskap? from 2008 (in Swedish).

For more information on AAT I can recommend:

Mario Vaneechoutte,  Algis Kuliukas,  Marc Verhaegen’s book Was Man More Aquatic In The Past? 
Fifty Years After Alister Hardy Waterside Hypothesis Of Human Evolution

David Attenborough’s Scars of Evolution for BBC (in the second programme does Professor Erika Schagatay talk about water birth practices among the Bajo Laut of southeastern Sulawesi).

Elaine Morgan’s official webpage on The Aquatic Ape Theory

Albert Wang-Chak’s poster “Possible aquatic adaptations in humans” that was presented in the Human Evolution Past, Present & Future conference in London 2013:


21 responses

  1. Michael

    I read the essay…and it does makes sense out of the “state of affairs” in the ongoing dabate as to whether the AAT is scientificly acceptable or not…it also contributes some for me hitherto unknown facts…e.g. that the world record in holding ones breath is nine 9 minutes…and presents some reserchers which I´ve not hitherto seen mentioned together with AAT….the essay deserves to be translated into the english language…

    September 6, 2011 at 3:25 pm

  2. marc verhaegen

    Hi Erik. It’s now clear that AAT is not something that happened 7-5 Ma, but during the Pleistocene.
    The term “aquatic ape” is an unfortunate misnomer IMO: it’s not about apes or australopiths (only about Homo), and it’s not about having been aquatic (a better term is “littoral”).
    But whatever name, the Hardy-Morgan theory is correct: Pleistocene Homo populations dispersed along coasts & rivers: they even reached Flores before 800 ka, and all archaic Homo fossils are found next to edible shellfish (work of J.Joordens, of S.Munro, and others), from Dmanisi and Mojokerto to the Cape, Boxgrove and Eritrea, from at least 1.8 Ma until 125 ka.
    The only “problem” IMO is that anti-AAT people keep attacking their own idea of what they believe AAT is (some sort of dolphin-like ancestors). Their “critiques” are typically irrelevant, misunderstanding, misrepresenting, obsolete, not essential (attacking possible sub-hypotheses), irrealistic and/or illogical (“crocodiles would have killed aquatic apes”).
    IMO we have to discern 2 theories:
    – the littoral theory of Homo (AAT s.s.): Pleistocene diaspora of Homo along coasts & rivers, beach-combing, wading & diving for waterside & aquatic foods,
    – the aquarboreal theory of apes: Mio-Pliocene hominoid adaptations (eg, vertical branch-hanging, floating & wading) in flooded forests (mangrove, gallery, swamp forests).
    For up-to-date insights, please
    – google “econiche Homo” on Pleistocene Homo evoluiton,
    – “aquarboreal” on Mio-Pliocene apes,
    – read our forthcoming ebook “Was Man More Aquatic in the Past? Fifty Years after Alister Hardy: Waterside Hypotheses of Human Evolution” M.Vaneechoutte, A.Kuliukas & M.Verhaegen eds 2011 Bentham Sci.Publ. + contributions of Elaine Morgan, Phillip Tobias, Michel Odent, Anna Gislén etc.,
    – see our paper “Pachyosteosclerosis suggests archaic Homo frequently collected sessile littoral foods” in HOMO J.compar.hum.Biol.62:237-247, 2011.
    Marc Verhaegen

    October 1, 2011 at 2:02 am

  3. Hi Marc! Thanks for your comment! I am glad to hear that the AAT-proponents nowadays support the idea that human beings have been aquatic for several millions year – and that Homo species have been more adapted to a marine life than for example Australopithecus.

    I agree with your statement that the term ‘Aquatic Ape’ is misleading and tempts other scientists and laymen to believe that AAT-proponents talk about dolphin-like forefathers, which of course is not the case.

    But don’t you think that the new theory also will be challenging in other ways? For what the new version suggests is that Homo Sapiens – physically – is more adapted to a life on coastlines than on land, mountains, desserts and forests. This idea doesn’t correspond to the idea that human beings are environmental generalists who are not physically linked to any environment but instead equipped with a creative brain. This idea has been flourishing since Charles Darwin and I think that many scientists and laymen will have difficulties in accepting the Aquatic Ape Hypothesis – as they believe in our brain rather than in our physical characteristics. This is still the paradigm of Anthropology.

    However, I welcome this development and I think that we should give more light to the works of Michael Odent and Igor Charkovsky when it comes to water birth and baby swimming and to Erika Schagatay when it comes to the diving reflex and our diving skills. Indeed, it seems that we can reach a higher potential in water than in any other element.

    October 4, 2011 at 1:05 pm

  4. What is “generalist”?
    An omnivorous mammal that used to live in the trees (early Primates) and evolved towards living in swamp forests (Mio-Pliocene apes), then to a littoral existence (Pleistocene Homo colonising different continetnes & islands along the coasts & rivers) & ultimately to a terrestrial life is very “generalist” IMO. To cope with all these different niches, we needed larger brains, and the abundance of poly-unsaturated fatty acids (esp.DHA) in aquatic milieus facilitated the development of larger brains. IOW, “generalist” is perhaps not wrong , but IMO it’s possible to be a lot more specific.

    November 8, 2011 at 9:05 pm

  5. I fully agree with the new version of the Aquatic Ape Theory, which you and other scientists advocate. But I am not sure that the proponents of this theory see the consequences which this new theory actually results in. Of course, human beings have been changing environments during the last seven millions of years, but nevertheless is our species (Homo sapiens) apparently more adapted to a life in oceans than in desserts, on mountains, in forests, etc. And therefore we can’t, from a physical and biological perspective, be recognized as “generalists” – as our body reaches a higher potential in water than in other environments.

    I think that most anthropologists (or people interested in the evolution of man) are giving too much attention to the human brain and that they underestimate our biological and physical adaptation. Yes, our brain is big, but I think it is simply because of the fatty acids that were available in water, not because that we were changing niches rapidly.

    I think that we need to formulate a new overall-theory, a new anthropological paradigm, about the origin of man. This should be a paradigm where 1) Homo sapiens’ biological and physical adaptation are given more attention than our brain and 2) where Homo sapiens is recognized as “a littoral apes” rather than an “environmental generalist” who is not physically linked to any environment.

    I think that future research on diving, baby swimming, water birth, etc. will make the connection between man and the sea even stronger.

    November 14, 2011 at 1:04 pm

  6. Hi all, nice to see our view mentioned here, but please in the correct form!

    Humans didn’t descend from “aquatic apes”, of course, although our ancestors were too slow & heavy for regular running over open plains as some anthropologists still believe.
    Instead, Pleistocene Homo populations simply followed the coasts & rivers in Africa & Eurasia (800,000 years ago, they even reached Flores more than 18 km overseas).
    – google “econiche Homo”
    – eBook “Was Man more aquatic in the past?” introd.Phillip Tobias
    – guest post at Greg Laden’s blog

    – the hominoids (“apes” including Australopithecus etc.!) since about 20 Ma (Miocene) lived in the branches & the water of swamp/flooded/mangrove forests, collecting fruits & nuts, hard-shelled foods, floating plants etc. (“aquarboreal”: aqua=water, arbor=tree),
    – archaic Homo since about 2 Ma (Pleistocene) dispersed along coasts & rivers, collecting aquatic & waterside foods, they dived for shellfish, seaweeds etc., butchered stranded whales & drowned ungulates, and gradually (at first seasonally?) followed the rivers inland (salmon etc.?), more & more wading instead of diving,
    – early H.sapiens since about 0.2 Ma was predom. a freshwater wader (+ spears, nets, dugouts, floating huts etc.) who gradually spent more & more time on dry land.

    In short schematically:
    – Mio-Pliocene aquarboreal hominoid theory + surface feeding,
    – Pleistocene littoral Homo theory + bottom diving.

    June 9, 2013 at 10:29 am

  7. arjaybe

    Very interesting to see the discussion continued here. I’m enjoying the evolution of my understanding of this hypothesis/theory. Thank you.


    June 9, 2013 at 5:47 pm

  8. Pingback: Aquatic Ape – The Theory Evolves | Green Comet

  9. Pingback: Shaggy Tyrants – Flying Tiger Comics

  10. cballes

    Has the thesis been translated yet?

    September 10, 2016 at 2:50 pm

    • Hi Clara! Unfortunately, it hasn’t been translated yet. Maybe I will give it a try.

      September 11, 2016 at 11:26 am

  11. Abigail

    Thank you so much for sharing your very good website

    October 14, 2017 at 1:05 am

  12. Pingback: Aquatic Ape Theory | Ancient Amnesia

  13. Koen

    The adaptations to a water environment is in favour of the ‘generalist’ ape/hominid theory. This is not at all a contradiction, on the contrary. The fysiological adaptations to water and sea/river food made our ancestors better generalists. The sea/river food could have been an important factor with respect to brain development and brain evolution. The generalist and ‘aquatic’ homo erectus might have developed different cultures and diets (land food, sea food), and occupied different habitats, which explains the great variety in homo species and brain capacity in the late pleistocene. Sea mammals like dolphins also have big brain capacity. AAT is a very plausible hypothesis, and actually proven IMHO.

    December 16, 2020 at 4:21 pm

    • Hi Koen! Thanks for your reply. Good to hear that you find the AAT a plausible hypothesis. However, I argue that humans have not been generalist throughout evolution, but that the end product with brain and physical characteristics made us become generalists newertheless. Homo Erectus had thicker bones than us that were superp for shallow water diving. It is also very plausible that the Achuelan hand axe (a trade mark for Homo erectus) were used to open shell fish. However, they might not have been very good at walking and running long distances. Our present feet and ability to run and walk long distances probably evolved in the transition period from Homo erectus to Homo sapiens which laid the foundation of the mixed abilities of contemporary humans. /Erik

      January 3, 2021 at 12:27 pm

      • Koen van Vlaenderen

        I assume that some homo erectus tribes returned to eat land fauna (scavengers) after sufficient development and evolution of the legs and feet, indeed (I agree with you). It is likely that different groups of homo erectus had different ‘cultures’ and food gathering/hunting habits, like dolphins, shimpanzees, etc … It was hypothesized that aquatic animal food was also an important factor for the evolutionary increase of brain-size and cranial capacity for the aquatic ape, but also for the hominids that evolved out of the aquatic ape, such that different groups of (for instance homo erectus and more evolved) hominids with different feeding habits evolved at different paces. I think it is no coincidence either that dolphins have the second highest cranial capacity versus body ratio, after modern humans. Homo sapiens could have had predecessors that ate aquatic food mainly. So basically, food habit differentiation lead to different paths of evolution, I think this was true during the entire evolution of hominids up to homo sapiens.

        January 3, 2021 at 7:29 pm

    • Yes, increased brain size is one of the strongest proofs of the AAH. Without eating large amounts of Omega 3 fatty acids, as for example DHA, our brains wouldn’t have grown big. Given that Homo sapiens has larger brains than Homo erectus, the consumption of marine food did probably intensify during the transition period from Erectus to Sapiens. This was probably made possible by walking long distances along the sea shore, development of new fishing techniques and increased use of rafts. Homo erectus may well have been scavengers as well, however it is likely that they were foremost feeding from marine resources since most Homo erectus fossils have been found in proximity to water (we have even found signs of them fromn the island of Socotra). I think we truly became environmental generalists during the so called great leap when we on on a larger scale devoted ourselves to cultural expressions such as jewelry and cave paintings.

      January 7, 2021 at 10:30 pm

  14. Pingback: The Aquatic Ape Theory | whatyareckon

  15. Hei. Svært godt oppgave Vattenapeteorin – Paradigmskifte eller pseudovetenskap? i 2008. Du vil kanskje være interessert i å høre om en ny tolkning for AAT som passer godt med alt som står der. Se

    September 13, 2021 at 2:07 pm

    • Koen van Vlaenderen

      Hi Allan, in my opinion your hypothesis makes a lot of sense. A chimpansee like primate on an isolated island is most likely the situation for the evolution of the aquatic ape. The question is indeed if ‘aquatic ape’ remains can be found on Bioko island. The fossil record is extremely unreliable imho, since the preservation of bones and skulls much depends on very stable climate/temperature conditions, like caves. Key periods in the evolution up to homo sapiens might not have left a trace of fossilised material. After homo erectus left Africa, the evolution of homo sapiens could also have happened outside Africa, for instance. The second largest brain/body ratio animal, the dolphin, has a similar diet of omega3 rich food, the same is true I suppose for the intelligent octopus. Exactly the right diet is most likely the most important factor for accelerated brain evolution. I think it is also likely that homo erectus groups that changed their diet back to land-food, did not develop brains as big as homo-erectus groups that stayed on the sea-coast diet. And this explains why there was a great variety in brain-size and intelligence in the homo species at some point in our history (some 50 thousand years ago). There were homo-sapiens in the past that had much larger brains than the average modern human.

      September 13, 2021 at 7:33 pm

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s