aquatic apes & custard elephants

The ‘aquatic ape’ hypothesis (it can’t be described as a theory) has been around for quite a while, & in fact I’ve blogged about it before. So I was sorry to hear that Sir David Attenborough, who’s done so much to promote conservation issues and enhance our understanding of the natural world, appeared to have given the idea some support. He’s certainly taken some flak for this (see here, for example), although at the same time other – ahem! – news outlets have picked up the ball and trotted off down the garden path with it.

Briefly, the aquatic ape hypothesis (I will NOT call it a theory) purports to explain the evolution of a number of aspects of our morphology: our relative hairlessness & the distribution of that hair, bipedalism, the way so many people like fish (I will put my hand up as an exception to this), distribution of body fat, & so on. ** Unfortunately for this particular just-so story, there’s good evidence that all these features did not evolve at the same time. Bipedalism, for example, pre-dates the chimp-human divergence, but the addition of fish to the diet seems to have appeared much later. Nor is there necessarily strong evidence of any links between a particular feature & the life aquatic. For example, while cetaceans are essentially hairless, seals, sealions and their relatives are covered with dense coats of fur.

Anyway, the hypothesis has recently been the focus of some entertaining parodies, among them the ‘space ape’ version (face-to-face copulation would really have been the only option, dontcha know? for otherwise the jetpacks would get in the way) and – as a conclusion to his explanation of why the aquatic ape idea doesn’t stack up – Henry Gee’s thought experiment involving the unlikely combination of elephants and custard.


** "& so on" includes the sinuses in our skulls (another feature that reinforces our African origins). Apparently they provided a buoyancy aid – yet they’re found in all mammals regardless of habitat.

[EDIT] However, courtesy of one Smut Clyde I find that the aquatic ape proposal has nothing on this.








15 thoughts on “aquatic apes & custard elephants”

  • herr doktor bimler says:

    “But why do we have empty spaces in our heads? It makes no sense until we consider the evolutionary perspective.”
    The idea that cavities within the skull provide a combination of strength *and* lightness is too subtle for some people. Then again, I am not entirely convinced that some people have *any* cavities within their skulls.
    IIRC the sinus-to-skull ratio is largest for elephants — more evidence for the elephant-custard theory!

  • Alison Campbell says:

    Nor am I convinced that 20cm^3 of air-filled space in the head would make that much difference in terms of flotation aids…

  • The Space-Ape thing was a nice distraction on twitter for a few days with people contributing different ideas. (There were quite a lot more, as you can imagine.)

  • herr doktor bimler says:

    Clicking through Henry Gee’s link and beyond:
    “Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is found in large amounts in seafood,” said Dr Michael Crawford, of Imperial College London.
    “It boosts brain growth in mammals. That is why a dolphin has a much bigger brain than a zebra, though they have roughly the same body sizes. The dolphin has a diet rich in DHA.

    Of course sharks also have DHA-rich diets. This does not seem to have had much effect on their brain size.
    I infer from the 5-kg brain size of elephants that they catch and eat lots of fish while swimming around in the custard.

  • herr doktor bimler says:

    When I wonder about primates who swim and whose diets include significant amounts of seafood (crustaceans and molluscs), I think of macaques. Their aquatic adaptations don’t seem to have turned them into humans.

  • For serious info on AAT (better terms than ‘aquatic ape’ are Littoral Theory or Coastal Dispersal Model), please google ‘greg laden blog verhaegen’: rather than running over savannas, Pleistocene Homo populations followed coasts & rivers, collecting different waterside & shallow aquatic plant & animal foods.
    Human Evolution soon publishes the proceedings of the symposium with David Attenborough on human waterside evolution ‘Human Evolution: Past, Present & Future’ in London 8-10 May 2013:
    SPECIAL EDITION PART 1 (end 2013)
    Introduction – Peter Rhys-Evans
    1. Human’s Association with Water Bodies: the ‘Exaggerated Diving Reflex’ and its Relationship with the Evolutionary Allometry of Human Pelvic and Brain Sizes – Stephen Oppenheimer
    2. Human Ecological Breadth: Why Neither Savanna nor Aquatic Hypotheses can Hold Water – JH Langdon
    3. Endurance Running versus Underwater Foraging: an Anatomical and Palaeoecological Perspective – Stephen Munro
    4. Wading Hypotheses of the Origin of Human Bipedalism – Algis Kuliukas
    5. The Aquatic Ape Evolves: Common Misconceptions and Unproven Assumptions about the So-Called Aquatic Ape Hypothesis – Marc Verhaegen
    6. The Epigenetic Emergence of Culture at the Coastline: Interaction of Genes, Nutrition, Environment and Demography – CL Broadhurst & Michael Crawford
    SPECIAL EDITION PART 2 (begin 2014) with 12 contributions
    –marc verhaegen, google
    echoniche Homo

  • Alison Campbell says:

    It would be useful if you would actually argue some of the key points supporting AAT here, rather than simply advising us to google a name & giving a list of topics.

  • Sorry for this late reply. The term “aquatic ape” is a bit misleading: our waterside past is not about apes of australopithecines, but about Pleistocene archaic Homo dispersing along African & Eurasian coasts & rivers (at least as far as the coastal sites of Mojokerto & Flores, the Cape, Angola & Happisburgh in England), beach-combing, diving & wading bipedally for littoral, shallow aquatic & waterside foods. The best information IMO can be found by googling researchGate marc verhaegen.

  • For recent info, google
    “aquatic ape theory made easy 2017”.
    The savanna idea (not a theory, not even a hypothesis) has been debunked numerous times: obviously, early-Pleistocene Homo dispersed intercontinentally following African & Eurasian coasts & rivers, google
    “Attenborough Brenna Schagatay reply”.

  • Alison Campbell says:

    Or you could, you know, summarise your own reasons for supporting the hypothesis here – rather than trying to drive traffic to your own page.
    Your second comment appears to be conflating a hypothesis about origins with the rather later waves of Homo dispersal.

  • marc verhaegen says:

    Dear Alison, sorry again for this very late reply. The littoral theory (the Pleistocene dispersal of archaic Homo along African and Eurasian coasts, rivers and islands) is based on the littoral traits that appear in archaic Homo, e.g. pachyosteosclerosis (uniquely seen in shallow-diving animals), platycephaly (long low flat brain-skull), ear exostoses (typical for diving animals), very large lungs (as in shallow-diving mammals), drastic brain expansion (DHA in seafoods) etc. – evidence that Pleistocene human ancestors frequently dived for shallow-aquatic foods. Unfortunately, many paleo-anthropologists trying to discuss the so-called aquatic ape hypothesis discuss their own ideas of what they think the hypothesis might be, rather than reading the recent literature on waterside hypotheses of ape and human evolution, e.g. Peter Rhys-Evans “The waterside ape” CRC Press 2019, or my 2013 paper in Human Evolution 28: 237-266: “The aquatic ape evolves: common misconceptions and unproven assumptions about the so-called Aquatic Ape Hypothesis” – Abstract: “While some paleo-anthropologists remain skeptical, data from diverse biological and anthropological disciplines leave little doubt that human ancestors were at some point in our past semi-aquatic: wading, swimming and/or diving in shallow waters in search of waterside or aquatic foods. However, the exact scenario – how, where and when these semi-aquatic adaptations happened, how profound they were, and how they fit into the hominid fossil record – is still disputed, even among anthropologists who assume some semi-aquatic adaptations. Here, I argue that the most intense phase(s) of semi-aquatic adaptation in human ancestry occurred when populations belonging to the genus Homo adapted to slow and shallow littoral diving for sessile foods such as shellfish during part(s) of the Pleistocene epoch (Ice Ages), presumably along African or South-Asian coasts.” For a short update (too extensive to discuss it here), I think it’s best to google “two incredible logical mistakes 2019 biology vs anthropocentrism”.

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