Kuliukas 2011 - Langdon's AAH Critique

[AlgisKuliukas]

Ch 15: Langdon's Critique of the Aquatic Ape Hypothesis: It's Final Refutation, or Just Another Misunderstanding? (pp 213-225)
Algis V. Kuliukas
in: Was Man More Aquatic In The Past?
Fifty Years After Alister Hardy Waterside Hypothesis Of Human Evolution
Eds. Vaneechoutte M., Verhaegen M., Kuliukas A.
eISBN: 978-1-60805-244-8, 2011.

Thus far, there has been no challenge to Langdon's 1997 critique of the aquatic ape hypothesis (AAH), despite its having a number of weaknesses. The paper lacks scholarliness as it does not draw upon the one published scientific investigation into the plausibility of the AAH in the literature, i.e., that byRoede et al. Langdon's summary of “anatomical evidence for the AAH” seems to have been directed against an exaggerated interpretation of Alister Hardy's hypothesis that humans were “more aquatic in the past”. Most of the critique was based on cursory and superficial comparisons with fully aquatic mammals, such as cetaceans, rather than considering whether human ancestors could have been more aquatic than those of apes. Even on this basis, Langdon considered eleven out of twenty-six traits to be “possible aquatic adaptations” or “consistent with the AAH”.

It is argued here that none of the specific hypotheses of the AAH have yet been refuted. Instead, what appears to have happened, is that individuals have been left to interpret certain ambiguities in arguments put forward by proponents of the hypothesis in their own way and then reject, or accept it on that basis. More than a decade later, significant new evidence has emerged, and other AAH-based models have been published, which demand serious reconsideration.

http://www.benthamdirect.org/pages/content.php?9781608052448/2011/00000001/00000001/0213.SGM

[AlgisKuliukas]

I sent a copy of the chapter to John Langdon to act as a critical reviewer, as the chapter is a direct critique of his JHE paper.

He gave me permission to post his reply here, and I so so in full...

Dear Algis,

Thank you for the opportunity to read your paper. You will not be surprised to know that I still disagree with you. In my response I would like to make the following points:

First, I think you missed the main point of my paper. I was not trying to disprove or even to rebut the AAH, but to argue a perspective on what constitutes parsimony.

Secondly, I disagree that I misinterpreted Morgan as much as you say. If I did, it is because I was trying to compile her writings into the most coherent argument I could. But I think you have misconstrued her, as well, into something with more inconsistencies.

Finally, I still content that the AAH is immensely unparsimonious.

I was afraid when I published my paper that the main point would be missed when people looked at the detailed critique of specific anatomical hypotheses. You missed it also. I was not trying to disprove the AAH because (as I stated explicitly) that cannot be done. The main point is this: Umbrella hypotheses, of which the AAH is an example, are attractive because they seem to tell a complete story; however, bundling many unproven hypothesis together does not make an umbrella hypothesis stronger or more parsimonious. In support of that thesis I tried to demonstrate that the individual hypotheses Morgan presented are merely untested hypotheses with equally plausible alternative untested explanations.

I contend that most of these individual selection scenarios are inherently untestable. Thus we are left with arguing plausibility and probability. This is where it is important to recognize what is and what is not parsimonious. The AAH is not parsimonious because it builds hypotheses on an extraordinary scenario whereas conventional models build on ordinary ones.

At the Ghent conference I observed that many of the so-called aquatic traits appear in the fossil record at different times in the Plio-Pleistocene. (The simplest example – our bipedalism and brain size evolved at different times and in different genera.) I asked when the aquatic period was supposed to exist? (Marc Verhaegen’s communications with me gave the argument that all hominins at least through Neanderthals were aquatic. I can only interpret that to mean that we are still in the aquatic period. I consider that absurd.)

Tobias, agreeing with my argument that one cannot place all the traits in an aquatic period, tried to pin Morgan down by asking her to identify the central and most important argument of the AAH, and she answered that it explained bipedalism. That places the aquatic phase in the Pliocene. Any traits that we evolved in the Pleistocene – that is, brain size, language, lengthening of the lower limbs, and anything else derived by Homo – is thus irrelevant to the AAH. I believe that confirms the thesis of my Umbrella paper.

I do recognize that there were earlier expressions of the AAH than Hardy’s paper that I did not acknowledge. My critique, however explicitly limited itself to Morgan’s presentation because trying to address all variations presented by all authors is like trying to shoot at a moving target and does not respect the integrity of her argument.

You argue that I critique an extreme and distorted form of the AAH – one that postulates fully aquatic behavior. Yes, that is how I interpreted Morgan’s writings. And I suggest that you have distorted and interpreted her writings in the opposite direction, perhaps in response to criticism by myself and others. Each of you pick and choose the arguments that make most sense to you to attempt a coherent picture, just as conventional anthropologists pick and choose their arguments to create their own versions of human evolution. Parts of the story are and will always be subjective because frankly we have no way of testing hypotheses about selective forces.

Here is an example of why I think the AAH needs to incorporate a fully aquatic phase. I believe Hardy and, I understand, Westenhofer (though I have not read him) were inspired initially by the parallel between humans and cetaceans in hairlessness and fat. In order for those similarities to be meaningful, the adaptive significance has to be the same in both taxa and relate to the water.

As I argued at Ghent and you point out in your paper, there are several recognizable reasons to be hairless. Cetaceans are hairless because hair is useless as insulation once water penetrates it; and if they never come out of the water, there is no point to having it. They make up for that loss in insulation with blubber and size. Mammals and birds that spend only part of their time in water have insulation, which is dried and oiled when they emerge. The exceptions -- hippos, walruses, elephant seals – are large-bodied. How can this help us understand human hairless unless we assume some combination of the following: our ancestors (1) never left the water or (2) were very large. I believe a fully aquatic life was very much on Hardy and Morgan’s minds when they wrote. Either that, of they did not look closely at the logic behind their arguments.

There is another possible model – suids. Verhargen makes much of the fact that pigs wallow in mud and the babyrussa likes swamps. Is that enough to build the AAH on? I have tried to find another unusual trait we share with pigs, and all I can come up with is that we have a very large dietary breadth.

But let’s consider fat. Humans do not have blubber approaching that of cetaceans. It is extremely difficult to know what amount of body fat is typical for our species, but we can be sure that the modern Western condition is not it. Yes our fat is widespread under our skin, but parts of our bodies are unprotected and readily subject to damage from the cold. I have completely rejected the notion that human fat is greater than that of most other mammals because of its value in insulation. I agree with you that its most critical function is to support the brain, especially in babies. That is what I wrote in my book, The Human Strategy. But that interpretation gives no support to the AAH.

My conclusion? Fat and hairlessness, two of the primary features that inspired the AAH, can relate only to fully aquatic niches and that Morgan and Hardy had this in mind. Or we can turn to more sensible terrestrial explanations. We can understand hairlessness if we see it in context with other adaptations of the skin, nervous system, and circulatory system that separately make no sense but together create a unique thermoregulatory strategy. We can understand fat if we see it in a context of nervous system, musculoskeletal, thermoregulatory, respiratory, and circulatory adaptations that support a level of sustained endurance almost without parallel among mammals. (Details are in my book.)

Many other of the features that Morgan cited as indicators of past aquatic adaptations make sense only if one assumes a major commitment to water. I challenge you to expand upon your model of our ancestors “merely living in waterside habitats” and see if many of the claimed adaptations make any sense. Unique respiratory modifications for swimming and diving don’t. Brain size does not. The more you imagine your ancestors living like modern humans, the harder it is to argue for major selective pressures requiring a redesign of the body.

Minor point: Oddly, some AAH enthusiasts have proudly presented photographs and anecdotes of chimps, gorillas, and orangs in water – bathing, wading, drinking, cooling off, etc. – as evidence for the AAH. You continue to argue (p 218) their aversion to water as evidence for it. Apparently they don’t mind water, but they don’t seem to like to swim. (I will take that as a hypothesis, but will happily change it with appropriate evidence.) I would like to know what happens to an ape in water. Does it float easily with so little body fat? Does the center of gravity tip the head up to make it easy or or down to make it difficult to breathe? Is our relative swimming ability a cause or consequence of our very different body build and tissue distribution? Would short-legged australopithecines have been more like humans or chimps? Don’t you think the question of why chimps don’t swim needs a little more investigation?

On the savannah hypothesis. When I wrote the paper I believed that, although the traditional story of human evolution placed our ancestors in a savannah environment, the environment alone was not seen as an explanatory agent in human evolution. Now I see that at least some anthropologists did indeed make that claim, although it makes no sense. Simply being in water or being in a savannah does not explain selection for any trait. One still has to hypothesize an adaptive value.

[Interestingly, although we now realize that australopithecines did not evolve in a grassland, there is increasing evidence to link Homo with environmental change in that direction – either in an area becoming more open or in an explicitly mosaic habitat. Potts, Conroy, and others now argue that environmental change itself was a driver of various traits appearing at about this time and I find this a compelling connection – especially since stone tools, evidence for carcass processing, genus Homo, robust australopithecines, brain expansion, and, a little later, redesign of the skeleton for running/endurance appear for the first time during this period. About 2.5 Mya climate changes appears to have crossed a threshold of tolerance that contributed to hominin evolution – but the individual changes still need to be explained.]

Bottom of page 220. My “less clear” #3 argument is that which I regard as the main thesis. You state that if 26 traits can be explained by a single hypothesis, that would be parsimonious. You miss the point that none has been or can be “explained” by the AAH. I respond that there are equally plausible explanations for these traits in a terrestrial framework. Does that not make the terrestrial model parsimonious? But few of those explanations (which are really more hypotheses) can be tested and none can be proven. The fact that many hypotheses can be devised for a given trait (e.g., bipedalism) in either scenario tells us that merely choosing an aquatic or terrestrial setting is not going to “explain” anything. We still have to articulate and test a hypothesis.

The AAH is not a theory -- a term many of its proponents use. It should be a hypothesis, but that is not how its proponents use it either. It is a paradigm. If you assumes it to be correct, then the world looks one way and you can construct models and hypotheses to explain human evolution. I believe that is the best way to understand the concept of a paradigm (though it differs to some degree from Kuhn’s usage.) The terrestrial approach is a different paradigm – the world looks different to me and I construct different models and hypotheses. I face the same problems testing and proving them.

Kuhn argued we can never compare different paradigms. I think we can, by looking at the starting assumptions and whatever evidence is available. The evidence I see is a terrestrial history for primates in general and hominoids more specifically. I do not see a time or place in the existing fossil record that would offer an opportunity for our ancestors to be any more committed to water than modern humans are. There was no niche where our ancestors experienced the extraordinary pressures of natural selection for aquatic adaptations that the AAH requires. I do see a species that developed culture to the extent that it gradually expanded its geographic range and the breadth of its ecological niche until it embraced coastal habitats as well as mountains, forests, deserts, and tundra.

The assumption that our ancestors experience two habitat shifts – to the water enough to experience dramatic physical adaptations and then away from it – in a matter of a couple of million years to be without parallel in evolutionary history and extremely unparsimonious. I see no strong evidence for it that cannot be interpreted equally well without such assumptions.

I don’t have the time to go through your paper sentence by sentence to comment on it. If you want me to respond to any point I have skipped over, let me know. I am happy to continue a friendly discussion.

Regards,

John

[AlgisKuliukas]

My reply to John's comments...

Dear Algis,

Thank you for the opportunity to read your paper. You will not be surprised to know that I still disagree with you. In my response I would like to make the following points:

First, I think you missed the main point of my paper. I was not trying to disprove or even to rebut the AAH, but to argue a perspective on what constitutes parsimony.

Secondly, I disagree that I misinterpreted Morgan as much as you say. If I did, it is because I was trying to compile her writings into the most coherent argument I could. But I think you have misconstrued her, as well, into something with more inconsistencies.

Finally, I still content that the AAH is immensely unparsimonious.

I was afraid when I published my paper that the main point would be missed when people looked at the detailed critique of specific anatomical hypotheses. You missed it also. I was not trying to disprove the AAH because (as I stated explicitly) that cannot be done. The main point is this: Umbrella hypotheses, of which the AAH is an example, are attractive because they seem to tell a complete story; however, bundling many unproven hypothesis together does not make an umbrella hypothesis stronger or more parsimonious. In support of that thesis I tried to demonstrate that the individual hypotheses Morgan presented are merely untested hypotheses with equally plausible alternative untested explanations.

I contend that most of these individual selection scenarios are inherently untestable. Thus we are left with arguing plausibility and probability. This is where it is important to recognize what is and what is not parsimonious. The AAH is not parsimonious because it builds hypotheses on an extraordinary scenario whereas conventional models build on ordinary ones.

At the Ghent conference I observed that many of the so-called aquatic traits appear in the fossil record at different times in the Plio-Pleistocene. (The simplest example – our bipedalism and brain size evolved at different times and in different genera.) I asked when the aquatic period was supposed to exist? (Marc Verhaegen’s communications with me gave the argument that all hominins at least through Neanderthals were aquatic. I can only interpret that to mean that we are still in the aquatic period. I consider that absurd.)

Tobias, agreeing with my argument that one cannot place all the traits in an aquatic period, tried to pin Morgan down by asking her to identify the central and most important argument of the AAH, and she answered that it explained bipedalism. That places the aquatic phase in the Pliocene. Any traits that we evolved in the Pleistocene – that is, brain size, language, lengthening of the lower limbs, and anything else derived by Homo – is thus irrelevant to the AAH. I believe that confirms the thesis of my Umbrella paper.

I do recognize that there were earlier expressions of the AAH than Hardy’s paper that I did not acknowledge. My critique, however explicitly limited itself to Morgan’s presentation because trying to address all variations presented by all authors is like trying to shoot at a moving target and does not respect the integrity of her argument.

You argue that I critique an extreme and distorted form of the AAH – one that postulates fully aquatic behavior. Yes, that is how I interpreted Morgan’s writings. And I suggest that you have distorted and interpreted her writings in the opposite direction, perhaps in response to criticism by myself and others. Each of you pick and choose the arguments that make most sense to you to attempt a coherent picture, just as conventional anthropologists pick and choose their arguments to create their own versions of human evolution. Parts of the story are and will always be subjective because frankly we have no way of testing hypotheses about selective forces.

Here is an example of why I think the AAH needs to incorporate a fully aquatic phase. I believe Hardy and, I understand, Westenhofer (though I have not read him) were inspired initially by the parallel between humans and cetaceans in hairlessness and fat. In order for those similarities to be meaningful, the adaptive significance has to be the same in both taxa and relate to the water.

As I argued at Ghent and you point out in your paper, there are several recognizable reasons to be hairless. Cetaceans are hairless because hair is useless as insulation once water penetrates it; and if they never come out of the water, there is no point to having it. They make up for that loss in insulation with blubber and size. Mammals and birds that spend only part of their time in water have insulation, which is dried and oiled when they emerge. The exceptions -- hippos, walruses, elephant seals – are large-bodied. How can this help us understand human hairless unless we assume some combination of the following: our ancestors (1) never left the water or (2) were very large. I believe a fully aquatic life was very much on Hardy and Morgan’s minds when they wrote. Either that, of they did not look closely at the logic behind their arguments.

There is another possible model – suids. Verhargen makes much of the fact that pigs wallow in mud and the babyrussa likes swamps. Is that enough to build the AAH on? I have tried to find another unusual trait we share with pigs, and all I can come up with is that we have a very large dietary breadth.

But let’s consider fat. Humans do not have blubber approaching that of cetaceans. It is extremely difficult to know what amount of body fat is typical for our species, but we can be sure that the modern Western condition is not it. Yes our fat is widespread under our skin, but parts of our bodies are unprotected and readily subject to damage from the cold. I have completely rejected the notion that human fat is greater than that of most other mammals because of its value in insulation. I agree with you that its most critical function is to support the brain, especially in babies. That is what I wrote in my book, The Human Strategy. But that interpretation gives no support to the AAH.

My conclusion? Fat and hairlessness, two of the primary features that inspired the AAH, can relate only to fully aquatic niches and that Morgan and Hardy had this in mind. Or we can turn to more sensible terrestrial explanations. We can understand hairlessness if we see it in context with other adaptations of the skin, nervous system, and circulatory system that separately make no sense but together create a unique thermoregulatory strategy. We can understand fat if we see it in a context of nervous system, musculoskeletal, thermoregulatory, respiratory, and circulatory adaptations that support a level of sustained endurance almost without parallel among mammals. (Details are in my book.)

Many other of the features that Morgan cited as indicators of past aquatic adaptations make sense only if one assumes a major commitment to water. I challenge you to expand upon your model of our ancestors “merely living in waterside habitats” and see if many of the claimed adaptations make any sense. Unique respiratory modifications for swimming and diving don’t. Brain size does not. The more you imagine your ancestors living like modern humans, the harder it is to argue for major selective pressures requiring a redesign of the body.

Minor point: Oddly, some AAH enthusiasts have proudly presented photographs and anecdotes of chimps, gorillas, and orangs in water – bathing, wading, drinking, cooling off, etc. – as evidence for the AAH. You continue to argue (p 218) their aversion to water as evidence for it. Apparently they don’t mind water, but they don’t seem to like to swim. (I will take that as a hypothesis, but will happily change it with appropriate evidence.) I would like to know what happens to an ape in water. Does it float easily with so little body fat? Does the center of gravity tip the head up to make it easy or or down to make it difficult to breathe? Is our relative swimming ability a cause or consequence of our very different body build and tissue distribution? Would short-legged australopithecines have been more like humans or chimps? Don’t you think the question of why chimps don’t swim needs a little more investigation?

On the savannah hypothesis. When I wrote the paper I believed that, although the traditional story of human evolution placed our ancestors in a savannah environment, the environment alone was not seen as an explanatory agent in human evolution. Now I see that at least some anthropologists did indeed make that claim, although it makes no sense. Simply being in water or being in a savannah does not explain selection for any trait. One still has to hypothesize an adaptive value.

[Interestingly, although we now realize that australopithecines did not evolve in a grassland, there is increasing evidence to link Homo with environmental change in that direction – either in an area becoming more open or in an explicitly mosaic habitat. Potts, Conroy, and others now argue that environmental change itself was a driver of various traits appearing at about this time and I find this a compelling connection – especially since stone tools, evidence for carcass processing, genus Homo, robust australopithecines, brain expansion, and, a little later, redesign of the skeleton for running/endurance appear for the first time during this period. About 2.5 Mya climate changes appears to have crossed a threshold of tolerance that contributed to hominin evolution – but the individual changes still need to be explained.]

Bottom of page 220. My “less clear” #3 argument is that which I regard as the main thesis. You state that if 26 traits can be explained by a single hypothesis, that would be parsimonious. You miss the point that none has been or can be “explained” by the AAH. I respond that there are equally plausible explanations for these traits in a terrestrial framework. Does that not make the terrestrial model parsimonious? But few of those explanations (which are really more hypotheses) can be tested and none can be proven. The fact that many hypotheses can be devised for a given trait (e.g., bipedalism) in either scenario tells us that merely choosing an aquatic or terrestrial setting is not going to “explain” anything. We still have to articulate and test a hypothesis.

The AAH is not a theory -- a term many of its proponents use. It should be a hypothesis, but that is not how its proponents use it either. It is a paradigm. If you assumes it to be correct, then the world looks one way and you can construct models and hypotheses to explain human evolution. I believe that is the best way to understand the concept of a paradigm (though it differs to some degree from Kuhn’s usage.) The terrestrial approach is a different paradigm – the world looks different to me and I construct different models and hypotheses. I face the same problems testing and proving them.

Kuhn argued we can never compare different paradigms. I think we can, by looking at the starting assumptions and whatever evidence is available. The evidence I see is a terrestrial history for primates in general and hominoids more specifically. I do not see a time or place in the existing fossil record that would offer an opportunity for our ancestors to be any more committed to water than modern humans are. There was no niche where our ancestors experienced the extraordinary pressures of natural selection for aquatic adaptations that the AAH requires. I do see a species that developed culture to the extent that it gradually expanded its geographic range and the breadth of its ecological niche until it embraced coastal habitats as well as mountains, forests, deserts, and tundra.

The assumption that our ancestors experience two habitat shifts – to the water enough to experience dramatic physical adaptations and then away from it – in a matter of a couple of million years to be without parallel in evolutionary history and extremely unparsimonious. I see no strong evidence for it that cannot be interpreted equally well without such assumptions.

I don’t have the time to go through your paper sentence by sentence to comment on it. If you want me to respond to any point I have skipped over, let me know. I am happy to continue a friendly discussion.

Regards,

John

Dear John
Thanks for spending so much time reading and responding to my paper. I’ll respond to you directly here but, if you give me permission to do so, I’d like to post your comments – and my reply to them – on the forum I mentioned in my first correspondence. (www.waterside-hypotheses.com)

On “missing the point”
I think everyone interested in evolution understands that disproof in such matters cannot be done, John, and that this was not the intention of your paper. You cannot deny, however, that some sort of rebuttal to the so-called “aquatic ape theory” was. It is certainly the overwhelming take-home message that comes from its pages. That is the point that I, and I’m sure everyone who read it, understood.

On “parsimony”
I cannot, for the life of me, see how it can be argued to be more parsimonious to explain 26 traits in many ways (as we both know there are many competing ideas just for individual ones, such as bipedal origins) than in just one – or at least ones that are very much closely related. You say that “The AAH is not parsimonious because it builds hypotheses on an extraordinary scenario” but what, exactly, is so extraordinary about the idea that our ancestors waded, swam and dived a little more than the ancestors of chimps and gorillas? No-one would claim it extraordinary that we climbed less than they did, or that we walked more than they did. What is it about the dreaded ‘a’ factor that is so “extraordinary”?
Later in your reply you expand on this argument but, I’d argue, that it is you, not us, who are missing the point. Yes, they’re only hypotheses – maybe not even that, maybe just ideas – but the material point is that, surely, if one idea explains the hooded nose, the descended larynx, the improved voluntary breath control, the changes to the human hair pattern, the increased adipocity in infants and several more, then that has to be more parsimonious than a vague set of many more, often contradictory, explanations.
And you return to this theme at the end by repeating the (in my opinion) misunderstanding that the “AAT” requires two habitat shifts. I will grant you that Hardy’s original piece, and Morgan’s early promotion of it, probably did so (what we now call the “U-turn” hypothesis) but, again, not all of us adhere to that view. My own version certainly does not. It assumes a single habitat – i.e. waterside – all the way from early Miocene ape through to modern Homo sapiens. In any case, in your JHE piece you (quite rightly) make the point that human evolution was, in all probability, a far more complex mosaic than we think. You can’t have it both ways.

On “appearance of traits in the fossil record”
I agree that bipedalism seems to have evolved much earlier than other human traits but this is not a unique problem for waterside hypotheses. Verhaegen is entitled to his opinion but his view is only one. Morgan certainly disagrees with him vehemently on several aspects of his thinking. Me too. I have my own different ideas. This is part of the problem, of course. There is not one “aquatic ape theory” – always a misnomer anyway – but several waterside hypotheses of human evolution. You, or Tobias, “pinning down” Morgan in the way you described might have given you some satisfaction but it wouldn’t have worked on me. I would have argued that bipedalism began early – through a wading-climbing origin, probably in all great apes – but that other human traits, such as nakedness, increased infant adipocity and a whole set of changes to the breathing apparatus evolved later, corresponding to the genus Homo. In this regard, I am closer to Verhaegen’s view.
What the aquaskeptic position always seems to do is find contradictions between two different proponents and purport to see them as one – and then reject “it” on that basis - a false premise of unity. I think they misrepresent these ideas (plural) when they do this. You say “I can only interpret that to mean that we are still in the aquatic period. I consider that absurd” and that, “yes”, you interpret Morgan’s ideas as “fully aquatic behaviour” – but did anyone ever really think there was an “aquatic period”, as such? Or just a “more aquatic period”? Hardy asked “Was Man MORE aquatic in the Past?” to which I would add, “… and if so, how much more aquatic?” No-one seems to have bothered to ask that – not even proponents – and one thing population genetics teaches us is that even slight selection can have profound effects on phenotype in relatively short periods of time.
We can argue until we’re blue in the face about what Hardy or Morgan meant in the past (and Morgan certainly does not argue for anything like a mermaid phase today) but I think a scientific critique of an idea should be careful not to make straw man arguments, especially when it accuses it of doing so. At best, it’s open to interpretation – by both sides. It seems to me no coincidence that those who don’t like the idea seem to exaggerate it to breaking point, whilst those who are more open to it, tend to scale it back. It was the very point Colin Groves made in his review of Roede et al. I’m sorry to say this but I think it was unscholarly that you made almost no reference to the Valkenburg symposium and, of course, did not quote Groves’ point. I think Colin is quite a conventional scientist, John.

On the human hair pattern and aquatic mammals
I think you exaggerate the ‘more aquatic’ argument for the human hair pattern, John. Next time you go to a swimming pool, take a look at some kids doing the breast stroke. You may notice something: The part of the body most likely to be above the surface of the water just happens to be the scalp – that part most likely to be covered with hair. As far as I can see, this is the only scenario that is so consistent with our hair pattern. The Sharp & Costil studies unequivocally showed that shaving what little body hair remains on men significantly reduced drag in passive “push-off” trials and, to repeat my earlier point, even slight selection could have had a profound effect like this.

On increased infant adipocity and “humans not having blubber approaching cetaceans”
Again, an exaggeration, I think. The key point is that human infants are significantly fatter than those of other primates and this needs an explanation. Clearly, you’re probably right to suggest that it correlates with encephalisation but it is difficult to untangle cause from effect here. If humans started living in coastal habitats, where infants were more at risk from drowning, then wouldn’t one expect that natural selection would favour those that were slightly more buoyant – and hence more likely to be rescued by their mothers? If so, it is entirely plausible that encephalisation may have followed as a consequence. The neo-Darwinian question comes to mind: why invest so heavily in such an expensive (energetically) organ so early in life when it will be 10 years at least before any extra intelligence resulting from that larger brain may give the individual any survival advantage? “Fat for buoyancy” provides a more direct and immediate selective advantage than “fat for brains” – but, of course, only in waterside habitats.
To reject these ideas on the basis that they can only make sense if we were as aquatic as dolphins seems to be another straw man, John. Your paper never considered if it was at the water’s edge that these things make most sense. As for your “more sensible terrestrial explanations” – what sense does it make to burden a mother with a fatter baby to carry on land with no fur for it to cling to, with the additional hindrance of her own increased adipocity to boot? It’s at the water’s edge where having fatter babies might help them survive. It’s at the water’s edge where sweat cooling (when going for a dip is not always the option to go for) makes most sense and is most likely to be replenished.
You claim that merely living in waterside habitats don’t explain these things (and more) but I respectfully disagree. In any case they’re not mutually incompatible – quite the reverse. Put it this way: Whatever explains human bipedalism – wading is only going to help it along. Whatever made humans lose most of their body hair, going swimming isn’t going to hinder it. Whatever made infants fat and large brained, reducing the risk of drowning isn’t going to make that less likely, is it?
Aquaskeptics always seem to want to exaggerate the claims and argue them in binary/black and white terms. Either we lived like dolphins, or the whole thing must be bunk. It’s a classic straw man approach, John – and you shouldn’t be doing that, particularly when you made the astonishing claim that decades of palaeoanthropological dogma (i.e. the savannah theory) was a mere invention of Elaine Morgan, so that she could knock it down.

On investigating apes in water
I am first in the queue petitioning for more studies to be done of apes in water aand on all aspects of these ideas. I tried to do my bit for my masters project. Bender & Oser are two PhD students doing some interesting work on chimps with Tobias currently. We’ll have to wait for their results, I guess. This really, is all Morgan and the rest of us have been asking for all these years – that the specialists stop ignoring this idea, and either pretending it doesn’t exist or else exaggerating to such an extent it sounds as daft as Von Daniken or Intelligent Design. The fact your paper is the only one ever specifically addressing this idea in a 1st class anthro journal in over 50 years bestows much credit on you personally, but - I’d argue – much shame on the field itself. Why is the dreaded ‘a’ factor so feared? Whoever decided that moving through water could not have influenced our phenotype, even in the slightest way?

On the savannah hypothesis
John, it’s good to read (at least I think this is what you’re saying) that you think it was a mistake to portray the ‘savannah theory’ as merely an invention of Elaine Morgan. It would be nice if you wrote a note to JHE conceding that point, as anyone reading your paper would not know that you had now changed your mind on it. You actually seem to be becoming a “savannah hypothesis” proponent yourself going by your bracketed points!

On theories, hypotheses and paradigms
I do not think you give us any credit here. Elaine moved on from the “theory” notion in her 1997 book, based on severe criticism of some aquaskeptics on the sap newsgroup - a book unfortunately published too late for you to critique. I certainly understand that it is not even one hypothesis, but several. This is why I have campaigned, successfully it seems, to rename the thing to “waterside hypotheses (plural) of human evolution”.
I disagree that the Kuhnian paradigm concept must necessarily be applied here. I’d prefer to argue for merely a shift in emphasis, an understanding from population genetics that even slight shifts in selection can, and do, make profound shifts in phenotypes in remarkably short evolutionary timescales and, most importantly, an opening of minds – as Philip Tobias has urged.

I simply do not agree that waterside hypotheses “require” the “extraordinary pressures of natural selection for aquatic adaptations” that you seem to believe. That, to me, is a far greater misunderstanding of the idea than anything I am guilty of.
Anyway, thanks again for spending the time to discuss this with me. I think this would all be of some interest to the broader public, so please allow me to post it on the new forum mentioned earlier and let’s discuss it there. If you prefer for this to remain a private discussion, however I will, of course, concur.

With best regards

Algis Kuliukas

[AlgisKuliukas]

John's reply of [19 January 2012 01:59]...

(Quote tags added around blocks of text from previous exchanges, for added clarity.)

On 1/18/12 10:52 AM, Algis Kuliukas wrote:
> Dear John
> Thanks for spending so much time reading and responding to my paper. I’ll respond to you directly here but, if you give me permission to do so, I’d like to post your comments – and my reply to them – on the forum I mentioned in my first correspondence. (http://www.waterside-hypotheses.com)

You have my permission to post my comments from this email and the
previous one. Please keep them in context.

On “missing the point”
I think everyone interested in evolution understands that disproof in such matters cannot be done, John, and that this was not the intention of your paper. You cannot deny, however, that some sort of rebuttal to the so-called “aquatic ape theory” was. It is certainly the overwhelming take-home message that comes from its pages. That is the point that I, and I’m sure everyone who read it, understood.

On “parsimony”
I cannot, for the life of me, see how it can be argued to be more parsimonious to explain 26 traits in many ways (as we both know there are many competing ideas just for individual ones, such as bipedal origins) than in just one – or at least ones that are very much closely related. You say that “The AAH is not parsimonious because it builds hypotheses on an extraordinary scenario” but what, exactly, is so extraordinary about the idea that our ancestors waded, swam and dived a little more than the ancestors of chimps and gorillas? No-one would claim it extraordinary that we climbed less than they did, or that we walked more than they did. What is it about the dreaded ‘a’ factor that is so “extraordinary”?
Later in your reply you expand on this argument but, I’d argue, that it is you, not us, who are missing the point. Yes, they’re only hypotheses – maybe not even that, maybe just ideas – but the material point is that, surely, if one idea explains the hooded nose, the descended larynx, the improved voluntary breath control, the changes to the human hair pattern, the increased adipocity in infants and several more, then that has to be more parsimonious than a vague set of many more, often contradictory, explanations.

In the context of this parsimony argument, please explain to me how the
assumption that human evolution played out in the water is any more of
"just one" idea than the assumption that it occurred on land?

Let me examine this point with respect to one feature, bipedalism, that
Elaine wants to be the core of her model. In her AAH book she ridicules
orthodox anthropology for its inability to resolve the inherently
unknowable question and instead generate many different hypotheses for
why we are bipedal. The most commonly cited contenders today are
energetic efficiency and food carrying; but others in the past include
tool use, upright position for scanning the environment, carrying
babies, etc. [Personally I think something is missing from all these. I
prefer a mix of ideas from Tuttle's hylobation hypothesis with the
energetic one. See my book for details.] What does the AAH replace this
with? Scenarios involving energetic efficiency arguments, retrieval of
food, use of tools to smash clam shells, upright position to keep the
head above water. How is this better? There is no single AAH answer,
though I assume you have your preference. Assuming an aquatic setting
has done nothing to explain bipedalism any better, or any of the other
25 traits. It has generated more untested/untestable hypotheses. But it
has also added what I call the "extraordinary" assumption -- postulating
an aquatic phase with two habitat shifts. This makes it less parsimonious.

And you return to this theme at the end by repeating the (in my opinion) misunderstanding that the “AAT” requires two habitat shifts. I will grant you that Hardy’s original piece, and Morgan’s early promotion of it, probably did so (what we now call the “U-turn” hypothesis) but, again, not all of us adhere to that view. My own version certainly does not. It assumes a single habitat – i.e. waterside – all the way from early Miocene ape through to modern Homo sapiens. In any case, in your JHE piece you (quite rightly) make the point that human evolution was, in all probability, a far more complex mosaic than we think. You can’t have it both ways.
As I have said, I explicitly addressed my paper to Morgan's version
because it is easier and more fair to build an argument to address one
model at a time. That is what you tell me I should do below, even as you
continue to criticize me for doing so.

Your watered-down version (pun intended) is quite different, and in my
mind constitutes an entirely different model that scarcely deserved the
term AAH. By keeping us in shallow water, it loses all the novelty of
the parallels with cetaceans that were so stimulating about the original
AAH, but it doesn't seem all that incompatible terrestrial scenarios.
You want to have hominins exploiting waterside and shallow water
resources? Fine. But where is the selection for aquatic adaptations?

One thing we know is that hominins are broad in what they can and do
exploit and became broader through time. Why not aquatic resources?
Current environmental reconstructions place robust australopithecines
rather consistently in habitats near water. However, gracile species
lived in more closed environments and Homo in more diverse and mosaic
habitats. The later we go in human evolution, the more evidence there is
that at least some humans are living away from coastlines in more
diverse places and are independent of aquatic resources.

Here is your challenge: How do you support an argument that we were so
dependent on aquatic resources that they significantly shaped our
evolution? How do you demonstrate we were not also benefiting from
eating terrestrial plants and animals to the point that we didn't need
to go into the water if we didn't want to? If you can't tackle these,
there is no AAH -- just a bunch of marooned untestable hypotheses.

On “appearance of traits in the fossil record”
I agree that bipedalism seems to have evolved much earlier than other human traits but this is not a unique problem for waterside hypotheses. Verhaegen is entitled to his opinion but his view is only one. Morgan certainly disagrees with him vehemently on several aspects of his thinking. Me too. I have my own different ideas. This is part of the problem, of course. There is not one “aquatic ape theory” – always a misnomer anyway – but several waterside hypotheses of human evolution.

Nor has there ever been one terrestrial model, though proponents of AAH
have always written as though there was.

You, or Tobias, “pinning down” Morgan in the way you described might have given you some satisfaction but it wouldn’t have worked on me. I would have argued that bipedalism began early – through a wading-climbing origin, probably in all great apes – but that other human traits, such as nakedness, increased infant adipocity and a whole set of changes to the breathing apparatus evolved later, corresponding to the genus Homo. In this regard, I am closer to Verhaegen’s view.
What the aquaskeptic position always seems to do is find contradictions between two different proponents and purport to see them as one – and then reject “it” on that basis - a false premise of unity. I think they misrepresent these ideas (plural) when they do this. You say “I can only interpret that to mean that we are still in the aquatic period. I consider that absurd” and that, “yes”, you interpret Morgan’s ideas as “fully aquatic behaviour” – but did anyone ever really think there was an “aquatic period”, as such? Or just a “more aquatic period”? Hardy asked “Was Man MORE aquatic in the Past?” to which I would add, “… and if so, how much more aquatic?” No-one seems to have bothered to ask that – not even proponents – and one thing population genetics teaches us is that even slight selection can have profound effects on phenotype in relatively short periods of time.
We can argue until we’re blue in the face about what Hardy or Morgan meant in the past (and Morgan certainly does not argue for anything like a mermaid phase today) but I think a scientific critique of an idea should be careful not to make straw man arguments, especially when it accuses it of doing so. At best, it’s open to interpretation – by both sides. It seems to me no coincidence that those who don’t like the idea seem to exaggerate it to breaking point, whilst those who are more open to it, tend to scale it back. It was the very point Colin Groves made in his review of Roede et al. I’m sorry to say this but I think it was unscholarly that you made almost no reference to the Valkenburg symposium and, of course, did not quote Groves’ point. I think Colin is quite a conventional scientist, John.

But this is exactly why I chose to focus only on Elaine's model. It is
unfair of you to criticize me for not addressing yours and other
versions also at the same time you accuse critics of constructing a
straw man by picking and choosing the weakest arguments.

On the human hair pattern and aquatic mammals
I think you exaggerate the ‘more aquatic’ argument for the human hair pattern, John. Next time you go to a swimming pool, take a look at some kids doing the breast stroke. You may notice something: The part of the body most likely to be above the surface of the water just happens to be the scalp – that part most likely to be covered with hair. As far as I can see, this is the only scenario that is so consistent with our hair pattern. The Sharp& Costil studies unequivocally showed that shaving what little body hair remains on men significantly reduced drag in passive “push-off” trials and, to repeat my earlier point, even slight selection could have had a profound effect like this.

If we are only wading, do you really think the minimal efficiency for
swimming gained by hair loss would outweigh the costs of losing
insulation and chilling once we get out of the water? Or the drag
created by long scalp hair? There are a lot of furry aquatic mammals
that didn't think so. And if pigs are worried about swimming efficiency,
I would make some better suggestions of how to evolve. This is why I ask
you to spell out your version in detail without assuming anything from
past AAH literature except direct evidence. Many of the basic arguments
of the AAH will no longer make sense. What I want to see and for you to
see is what is left?

On increased infant adipocity and “humans not having blubber approaching cetaceans”
Again, an exaggeration, I think. The key point is that human infants are significantly fatter than those of other primates and this needs an explanation. Clearly, you’re probably right to suggest that it correlates with encephalisation but it is difficult to untangle cause from effect here. If humans started living in coastal habitats, where infants were more at risk from drowning, then wouldn’t one expect that natural selection would favour those that were slightly more buoyant – and hence more likely to be rescued by their mothers? If so, it is entirely plausible that encephalisation may have followed as a consequence.
The neo-Darwinian question comes to mind: why invest so heavily in such an expensive (energetically) organ so early in life when it will be 10 years at least before any extra intelligence resulting from that larger brain may give the individual any survival advantage? “Fat for buoyancy” provides a more direct and immediate selective advantage than “fat for brains” – but, of course, only in waterside habitats.

Do I understand this correctly? We only evolved large brains because we
had fat babies? Please.

To reject these ideas on the basis that they can only make sense if we were as aquatic as dolphins seems to be another straw man, John. Your paper never considered if it was at the water’s edge that these things make most sense.
As for your “more sensible terrestrial explanations” – what sense does it make to burden a mother with a fatter baby to carry on land with no fur for it to cling to, with the additional hindrance of her own increased adipocity to boot? It’s at the water’s edge where having fatter babies might help them survive. It’s at the water’s edge where sweat cooling (when going for a dip is not always the option to go for) makes most sense and is most likely to be replenished.

Sweating makes more sense away from water, not nearby. Yes, there has to
be access to drinking water; but there is no need to cool down if you
are not exerting yourself on land.

You claim that merely living in waterside habitats don’t explain these things (and more) but I respectfully disagree.
Then you have just swallowed the fallacy that makes the Savanna
Hypothesis unacceptable (see below). Positing a setting does not create
or test hypotheses of selection.

In any case they’re not mutually incompatible – quite the reverse. Put it this way: Whatever explains human bipedalism – wading is only going to help it along. Whatever made humans lose most of their body hair, going swimming isn’t going to hinder it. Whatever made infants fat and large brained, reducing the risk of drowning isn’t going to make that less likely, is it?

Careful. I read this paragraph as a full retreat. You suggest that all
these traits may have evolved for good terrestrial reasons and we went
wading later. Are ancestors were just like the ones in the conventional
textbooks except that they liked the beach. If that is what your really
intend, then what does your AAH offer? It is getting fuzzier and weaker
in its explanatory value.

Aquaskeptics always seem to want to exaggerate the claims and argue them in binary/black and white terms. Either we lived like dolphins, or the whole thing must be bunk. It’s a classic straw man approach, John – and you shouldn’t be doing that, particularly when you made the astonishing claim that decades of palaeoanthropological dogma (i.e. the savannah theory) was a mere invention of Elaine Morgan, so that she could knock it down.

On investigating apes in water
I am first in the queue petitioning for more studies to be done of apes in water aand on all aspects of these ideas. I tried to do my bit for my masters project. Bender & Oser are two PhD students doing some interesting work on chimps with Tobias currently. We’ll have to wait for their results, I guess. This really, is all Morgan and the rest of us have been asking for all these years – that the specialists stop ignoring this idea, and either pretending it doesn’t exist or else exaggerating to such an extent it sounds as daft as Von Daniken or Intelligent Design. The fact your paper is the only one ever specifically addressing this idea in a 1st class anthro journal in over 50 years bestows much credit on you personally, but - I’d argue – much shame on the field itself. Why is the dreaded ‘a’ factor so feared? Whoever decided that moving through water could not have influenced our phenotype, even in the slightest way?

On the savannah hypothesis
John, it’s good to read (at least I think this is what you’re saying) that you think it was a mistake to portray the ‘savannah theory’ as merely an invention of Elaine Morgan.

Yes, I made a mistake. I became convinced of that at the Ghent
conference. Some anthropologists, but not all -- despite what AAH
proponents have said -- bought into the Savanna Theory. Let's be clear
on definitions: the Savanna Theory contends that living on the savanna
was necessary and sufficient to explain the evolution of many human
traits. Whether it was necessary deserves ongoing discussion. It was
never sufficient -- the savanna setting along cannot explain anything.
However, merely citing the savanna as the scene of human evolution does
not constitute the Savanna Theory. That is where Elaine and others
misrepresented anthropology.
No, I am not reverting to the Savanna Theory now, because I recognize
that we still need to construct the specifics of the model -- living
where the environment was changing is not a sufficient explanation.

It would be nice if you wrote a note to JHE conceding that point, as anyone reading your paper would not know that you had now changed your mind on it. You actually seem to be becoming a “savannah hypothesis” proponent yourself going by your bracketed points!

On theories, hypotheses and paradigms
> I do not think you give us any credit here. Elaine moved on from the “theory” notion in her 1997 book, based on severe criticism of some aquaskeptics on the sap newsgroup - a book unfortunately published too late for you to critique.

She gave me a copy. It is clearly her best statement of her hypothesis,
but I didn't find much new in it.

I certainly understand that it is not even one hypothesis, but several. This is why I have campaigned, successfully it seems, to rename the thing to “waterside hypotheses (plural) of human evolution”.
I disagree that the Kuhnian paradigm concept must necessarily be applied here. I’d prefer to argue for merely a shift in emphasis, an understanding from population genetics that even slight shifts in selection can, and do, make profound shifts in phenotypes in remarkably short evolutionary timescales and, most importantly, an opening of minds – as Philip Tobias has urged.
I simply do not agree that waterside hypotheses “require” the “extraordinary pressures of natural selection for aquatic adaptations” that you seem to believe. That, to me, is a far greater misunderstanding of the idea than anything I am guilty of.
Anyway, thanks again for spending the time to discuss this with me. I think this would all be of some interest to the broader public, so please allow me to post it on the new forum mentioned earlier and let’s discuss it there. If you prefer for this to remain a private discussion, however I will, of course, concur.

With best regards

Algis Kuliukas

[AlgisKuliukas]

> You have my permission to post my comments from this email and the
previous one. Please keep them in context.

Thanks John. I really appreciate your openness. I think this exchange could be informative to many people interested in these ideas. With your permission, I’ll post these exchanges between on this until you instruct me otherwise.
You may like to view the thread for yourself here: viewtopic.php?f=10&t=133.

AK : On “missing the point”
AK : On “parsimony”

> In the context of this parsimony argument, please explain to me how the
assumption that human evolution played out in the water is any more of
"just one" idea than the assumption that it occurred on land?

Ok, that’s a fair point but you have to admit that, for example, “more swimming” is just one idea and it explains several of the “list of 26” that you criticised. If one takes just those, and compare the alternatives that you cited, they comprise more than one idea. How can this be more parsimonious?
I agree it’s not “just one” idea – it’s several. Hence waterside hypotheses (plural) of human evolution. But they are united in one, important, regard – they all argue that most of the physical differences between humans and chimps/gorillas can more easily be explained by postulating adaptations to wading, swimming and diving. What is the “orthodox” alternative? Can you express it in a simple sentence like this, or is suddenly, the simplicity of waterside hypotheses a problem? Isn’t that was parsimony is supposed to be about?

> Let me examine this point with respect to one feature, bipedalism, that
Elaine wants to be the core of her model. In her AAH book she ridicules
orthodox anthropology for its inability to resolve the inherently
unknowable question and instead generate many different hypotheses for
why we are bipedal. The most commonly cited contenders today are
energetic efficiency and food carrying; but others in the past include
tool use, upright position for scanning the environment, carrying
babies, etc. [Personally I think something is missing from all these. I
prefer a mix of ideas from Tuttle's hylobation hypothesis with the
energetic one. See my book for details.] What does the AAH replace this
with?

I would argue that it doesn’t replace them, it adds to them. I agree that being large and arboreal is a necessary predicate to hominin bipedal origins. Clearly wading is not sufficient alone, otherwise all semi aquatic mammals would move bipedally in shallow water, when they don’t – only large primates do that. Equally, being large and arboreal isn’t sufficient alone either, otherwise why aren’t all great apes bipedal like us?
I’m glad you picked bipedalism because in my view it the most clear cut, demonstrable, human characteristic that waterside hypotheses help with.

Which other published scenario (and I’ve listed over 30 – see UploadedFiles/Wading%20Paper/Supporting%20Files/Model_Evaluator.html) can say this:

Place a group of otherwise quadrupedal apes in scenario x, and watch them all switch to unsupported, bipedal locomotion (not just a transitional posture) for as long as the scenario prevails. Which scenario would kill them, if they were to continue to move quadrupedally?

I find it astonishing that this – by far the most obvious, demonstrable, Darwinist – idea on bipedal origins has been all but ignored by the field for over 50 years.

Your two paragraph critique of it in the JHE paper is about the only thing a researcher would be able to find critiquing the wading idea in the palaeoanthropological literature. And, sorry to say this, but that ‘critique’ was the poorest of all your critiques. You did not say one word about this elephant in the room (above) but instead cherry picked a couple of arguments from Elaine’s “Scars’” book and then offered your own personal favourite (Tuttle’s “upwardly mobile” idea) instead. That was really awful, John. How on earth did it get through peer review?
The wading hypothesis is complimentary to most of the others, including arboreal ones and even the energy efficiency argument – which I also support.

> Scenarios involving energetic efficiency arguments, retrieval of
food, use of tools to smash clam shells, upright position to keep the
head above water. How is this better?

How is this better? It allows them to breath, John. How do you propose the improved energy efficiency started? Why did it not apply to chimps and gorillas, but only us?

> There is no single AAH answer,
though I assume you have your preference. Assuming an aquatic setting
has done nothing to explain bipedalism any better, or any of the other
25 traits. It has generated more untested/untestable hypotheses. But it
has also added what I call the "extraordinary" assumption -- postulating
an aquatic phase with two habitat shifts. This makes it less parsimonious.

Wading induces bipedalism in extant apes like no other factor. It is a no brainer. Practically the entire fossil record places early hominins by the water’s edge. What would be extraordinary would be if they never waded. And yet, paleoanthropologists seem to think the idea is as extraordinary as Von Daniken’s aliens from space or Intelligent Design. Your paper endorsed that kind of comparison.

> As I have said, I explicitly addressed my paper to Morgan's version
because it is easier and more fair to build an argument to address one
model at a time. That is what you tell me I should do below, even as you
continue to criticize me for doing so.

In your paper, you could have made that clearer. You should have drawn upon Roede et al, which at least would have made your critique more scholarly. I don’t think parading 26 traits giving them equal weighting, as if for ridicule, when Elaine emphasised three or four and grouped others clearly as minor, as being very “fair”, John.

> Your watered-down version (pun intended) is quite different, and in my
mind constitutes an entirely different model that scarcely deserved the
term AAH. By keeping us in shallow water, it loses all the novelty of
the parallels with cetaceans that were so stimulating about the original
AAH, but it doesn't seem all that incompatible terrestrial scenarios.
You want to have hominins exploiting waterside and shallow water
resources? Fine. But where is the selection for aquatic adaptations?

Well my “river apes… coastal people” idea is different from Hardy’s original, of course. But then so is Verhaegen’s, Ellis’, Niemitz’s, Crawford’s etc. This is just one reason why the term “aquatic ape theory” is totally inappropriate. I would have hoped that the author of the one critique published in a 1st class anthro journal would have picked up on this but, frankly, you seemed more interested in using the most extreme “cetacean” analogues you could find to ridicule.

The selection comes from wading, swimming and diving. Why do aquaskeptics always have to think in such black & white terms: either we were “aquatic” or we were “terrestrial” – either/or. If our ancestors did more wading, swimming and diving than chimp ancestors did, we’d expect (wouldn’t we?) that more of our ancestors would drown than theirs. If we are Darwinists (and we are, right?) one would expect that those genes that made us more likely to drown – even if only slightly more - would gradually be removed from the gene pool. The more wading, the more bipedal our ancestors would be. The more swimming the more they’d lose their body hair and the more selection there’d be for fatter (more buoyant) infants. Just look at the diversity, due to natural selection, in human populations just in the last 80Ka from living a little further from the equator, a little higher in the mountains, or from eating more dairy produce. Why do you find it so “extraordinary” that a little more wading, swimming and diving – over millions of years – could have had such an impact?

> One thing we know is that hominins are broad in what they can and do
exploit and became broader through time. Why not aquatic resources?
Current environmental reconstructions place robust australopithecines
rather consistently in habitats near water. However, gracile species
lived in more closed environments and Homo in more diverse and mosaic
habitats. The later we go in human evolution, the more evidence there is
that at least some humans are living away from coastlines in more
diverse places and are independent of aquatic resources.

> Here is your challenge: How do you support an argument that we were so
dependent on aquatic resources that they significantly shaped our
evolution? How do you demonstrate we were not also benefiting from
eating terrestrial plants and animals to the point that we didn't need
to go into the water if we didn't want to? If you can't tackle these,
there is no AAH -- just a bunch of marooned untestable hypotheses.

Crawford et al have made a good case for that, I think. I know you oppose them too.

Here’s how I meet your challenge: Usually, in biology, when one species is clearly better able to move through a given substrate than another – the standard assumption for Darwinists is that natural selection provides the simplest explanation.

Why are gibbons more adept in trees than us? – Clearly, because since the last common ancestor, their lineage has moved through trees more than ours, the genes that made them less adept were eliminated in their lineage but persisted, to a large extent, in ours. Same with chimps but to a lesser degree.

Why are humans better able to do endurance running than chimps? Probably because since the last common ancestor, our ancestors have needed to do more running on dry land than theirs. Agreed?

Why do the “rules” suddenly change when we think about swimming? Young children, long before they have mastered any technology, can be taught to swim. They can do this totally naked, without the use of the sort of equipment that has allowed humans to live in some of the other places that the “super generalist” arguments hold.

If human ancestors had been exposed to more selection from swimming and diving than chimp ancestors, we’d expect that we’d be better able to swim and dive than them. What do we find? Exactly that. Billions of humans have been observed swimming – a handful of chimps. Thousands of humans have swam across stretches of water greater than 5km wide and yet the river Congo has been sufficient to isolate bonobos from chimps and gorillas for millions of years. Humans have been observed diving for food and it is well documented that we have a mammalian diving reflex that is rather good for a purely terrestrial mammal. Similar studies should be done with chimps to test if there are physiological differences but, anecdotally, few chimps have ever been observed diving – never in the natural world as far as I know.

I have to say that I was disappointed that you made no reference at all to the relative swimming abilities of chimps and humans in your JHE paper – you only compared us with ‘true aquatics’ like dolphins. I think it’s called a straw man argument, John.

AK: On “appearance of traits in the fossil record”

> Nor has there ever been one terrestrial model, though proponents of AAH
have always written as though there was.

I think that’s a little unfair. Elaine parodies the “orthodox” explanations as much/little as you do.

> But this is exactly why I chose to focus only on Elaine's model. It is
unfair of you to criticize me for not addressing yours and other
versions also at the same time you accuse critics of constructing a
straw man by picking and choosing the weakest arguments.

Clearly I cannot criticise you for not addressing my ideas when they did not even exist at that time.

Morgan and Hardy both made statements that showed they were not postulating anything as extreme as the idea you seem to be criticising. (Hardy’s “less aquatic than otters” comment and Morgan’s “crossing stretches of water with the aid of log”) but instead of considering those, you only considered a “full on” cetacean-like caricature – the sort of thing that is easy to sneer at. It’s called a “straw man” argument, John, that’s why I have criticised you for doing it.

AK : On the human hair pattern and aquatic mammals

> If we are only wading, do you really think the minimal efficiency for
swimming gained by hair loss would outweigh the costs of losing
insulation and chilling once we get out of the water? Or the drag
created by long scalp hair? There are a lot of furry aquatic mammals
that didn't think so. And if pigs are worried about swimming efficiency,
I would make some better suggestions of how to evolve. This is why I ask
you to spell out your version in detail without assuming anything from
past AAH literature except direct evidence. Many of the basic arguments
of the AAH will no longer make sense. What I want to see and for you to
see is what is left?

Assuming humans evolved in hot equatorial Africa, yes, I think it would. Presumably you agree, seeing you argue for the sweat cooling explanation. Sweat cooling is just a virtual proxy for “going for a dip” anyway. The scalp hair would be flowing behind the head and might even help the fluid mechanics of drag, in reducing votices etc. Clearly more studies need to be done here but I think it is a little facile to reject so easily the one scenario that fits the human hair pattern so well. Swimming face down in coastal shallows is almost a perfect match. The position and orientation of the eye brows, eye lashes etc too.

I’ll spell out my “river apes… coastal people” model in detail in time. I’m writing a book about it but there’s been the eBook, a have my PhD to try to finish etc.

AK: On increased infant adipocity and “humans not having blubber approaching cetaceans”

> Do I understand this correctly? We only evolved large brains because we
had fat babies? Please.

It’s easy to sneer, John. I didn’t say “only”, did I? I’d argue that it was obviously a combination of diet – as Crawford et al argue, the marine food chain can only help there – and the adaptive benefits resulting from greater intelligence. But it being a side effect of having fat babies is as plausible as it being the cause of fat babies.

> Sweating makes more sense away from water, not nearby. Yes, there has to
be access to drinking water; but there is no need to cool down if you
are not exerting yourself on land.

The further away from water the less likely there’s access to drinking water. The best way to cool down is to go for a dip, as anyone living in a hot climate knows.

AK: You claim that merely living in waterside habitats don’t explain these things (and more) but I respectfully disagree.

> Then you have just swallowed the fallacy that makes the Savanna
Hypothesis unacceptable (see below). Positing a setting does not create
or test hypotheses of selection.

Please explain why fat babies (and fat, naked mothers who still have to carry them) make more sense away from the water’s edge.

> Careful. I read this paragraph as a full retreat. You suggest that all
these traits may have evolved for good terrestrial reasons and we went
wading later. Are ancestors were just like the ones in the conventional
textbooks except that they liked the beach. If that is what your really
intend, then what does your AAH offer? It is getting fuzzier and weaker
in its explanatory value.

It’s not a retreat, John, just an acceptance that there isn’t a simple dichotomy of what’s on offer. It’s not either a) our ancestors started to live like dolphins, or b) they never waded, swam and dived enough to affect their selection. How about c), it was something in between?
Do you detect a recurring theme in this discussion, John? I do. You want to exaggerate the idea to ridiculous levels that can easily be dismissed. I don’t. I merely want to suggest that some wading, swimming and diving in the locomotor repertoire of human ancestors is plausible and, as long as one understands a little population genetics, is helpful.

Please, let’s stop calling them “AAT”. Hardy and Morgan never meant to suggest that our ancestors were ever “aquatic” in any commonly accepted sense of the word. Hardy merely asked “Was Man More Aquatic in the Past?” not “Was Man evolved from an Aquatic Ape?” It was Desmond Morris who coined the phrase and I think he did so in an ironic sense – of the apes, which we understand are very much not aquatic, we are the most aquatic (but still not much). And although Hardy and Morgan saw this ‘phase’ as a U-turn that ended before humans had evolved, not all of us do. So it’s not really apes eather. Please can we refer to them (plural) as waterside hypotheses of human evolution?

> No, I am not reverting to the Savanna Theory now, because I recognize
that we still need to construct the specifics of the model -- living
where the environment was changing is not a sufficient explanation.

No, I agree. Living in more open spaces explains very little apart from losing arboreality. Waterside hypotheses explain for more.

Algis Kuliukas

[AlgisKuliukas]

John's reply [19 Jan 2012]

Threads within threads within threads get very confusing, so I am
deleting previous text. Let me know if there is a particular point you
want me to follow. Otherwise I will just pick a few.

On Bipedalism. Back in the 1970s Mike Rose tried to tackle the issue by
asking the question, under what circumstances do other primates walk
bipedally. He then went to the field and studied baboons. His
conclusion, after listing a number of reasons to be bipedal, was that
they rose up to pick food items from low branches and shrubs. Kevin Hunt
came to the same conclusion after studying chimpanzees in the 1990s.
This approach lies behind many of the hypotheses of bipedalism that have
been generated -- carrying food, surveying the landscape, display. And
more recently wading can be added to the list as just one more reason a
primate might stand up. But such arguments have never moved beyond that
hypothesis stage and I suspect they cannot; the field has largely
abandoned this approach as unproductive and unresolvable. One thing
these arguments do demonstrate is that all primates are facultatively
bipedal. Some -- the living hominoids -- are more so than others; and
the anatomical shift to obligate bipedalism is not as huge a hurdle as
Morgan has made it out to be.

On your definitive test: "Place a group of otherwise quadrupedal apes in
scenario x, and watch them all switch to unsupported, bipedal locomotion
(not just a transitional posture) for as long as the scenario prevails.
Which scenario would kill them, if they were to continue to move
quadrupedally?" Quadrupedal or bipedal animals in water either stay in
the shallows or swim. They are not going to wait until the water comes
over their heads and drown and they are not going to become dependent on
resources they cannot access. This is a preposterous scenario and it
presupposes rather than demonstrates an aquatic niche.

This brings us back to my argument that the AAH is a paradigm -- a set
of prior assumptions made before the questions are asked. If you support
those assumptions (about aquatic commitment) by conjectures that assume
them (e.g., bipedalism), the reasoning is circular. [Now I rather wish I
had used the language of paradigm than coin the term 'umbrella hypothesis'.]


On focusing on Morgan. You continue to criticize me for addressing only
Morgan's version of the AAH. I recognized in my paper, as I do now, that
others were making contributions; but honestly, Algis, how may other
versions were developed comprehensively in print in 1997? How many now?
I am aware of Verhaegen's later one but I won't pretend to read his book
in Dutch. Others, like Cunane, spin off from the AAH, but do not have a
fully developed version. Most of you -- yourself included -- focus on a
small cluster of attributes and by implication accept Morgan's more
completely articulated scenario to fill it out. I repeat that the
changes you have made -- moving from a fully aquatic life to merely
wading had torn the guts out of the original AAH so that it is now much
weaker in terms of explanatory power than it was. It waffles
inconsistently between merely wading and a vital dependence on swimming
and diving and presents a moving target. Even your emails do that. If
you really try to spell out your model and articulate the hypotheses it
uses for each trait it is trying to explain, I think you will see that.


On recurring themes. Yes there are recurring themes. I wrote my 1997
paper on Morgan's model drawn from all her writings at the time because
I recognize the problem of picking and choosing arguments from different
authors. I don't think I exaggerated it to ridiculous levels and I do
think you are revising what they wrote after the fact and, at the same
time, criticizing me for not addressing models that had not been
articulated before 1997. In your revision, you are hanging on to
arguments that were logically coherent for a fully aquatic phase, but at
the same time denying that phase.

I am really trying to understand what you propose now, but I admit I
have to fill in with what was written in the past. Do I understand that
your current argument can be summarized by "our modern
swimming/wading/diving ability has been selected for because of our
dependency on a semi-aquatic niche"? That is not at all what Morgan
argued. She was quite explicit, as was Hardy's title, that we are less
adapted for water now than we used to be. For example, Morgan proposed
traits, such as a nasal sphincter, that doesn't exist any more. If that
is indeed what you intend, then any attempt to articulate it that refers
to previous models will fail -- it will be forever confused with them.

Why are we better swimmers? I won't disagree that we are better than
chimps. Many of the adaptations that we use for swimming clearly relate
to other activities: e.g., shoulder mobility and overhead reach to
climbing; our fully extended joints and weight distribution in the lower
limbs to bipedal walking/running; less dense bones for shock absorption;
possibly larger lungs for sustained endurance (that's my prediction, but
I have never seen measurements).
But I do believe our species' swimming ability is overrated. Is there
any species with a partially aquatic niche that that drowns as often as
humans? (My current research has me looking through death certificates
for a community in Indiana in the 1800s. I am surprised how many
children and adults drowned accidentally while bathing or crossing
rivers or falling off canal boats or even falling into a tub or cistern.
Anecdotal evidence is weak.) Is there any species with a partially
aquatic niche where a majority of its population never swims? (No, I
cannot support that figure, but I suspect it is accurate.) Humans have
to learn and practice to in order to swim well.
So are we, as a species, really good swimmers? I don't know how to
answer that. What would you expect "good" to mean in a species that has
been adapting to water since the Miocene? Perhaps not having to be face
down in the water so we can't breathe comfortably and swim at the same
time is a place to start.


--
John H. Langdon

[AlgisKuliukas]

I agree with your "culling" of the threads. It does get cumbersome. But, now that you've done that culling, I'll reply by inserting commenst after each point, if that's ok.

You can always "re-cull".

Threads within threads within threads get very confusing, so I am
deleting previous text. Let me know if there is a particular point you
want me to follow. Otherwise I will just pick a few.

On Bipedalism. Back in the 1970s Mike Rose tried to tackle the issue by
asking the question, under what circumstances do other primates walk
bipedally. He then went to the field and studied baboons. His
conclusion, after listing a number of reasons to be bipedal, was that
they rose up to pick food items from low branches and shrubs. Kevin Hunt
came to the same conclusion after studying chimpanzees in the 1990s.
This approach lies behind many of the hypotheses of bipedalism that have
been generated -- carrying food, surveying the landscape, display. And
more recently wading can be added to the list as just one more reason a
primate might stand up. But such arguments have never moved beyond that
hypothesis stage and I suspect they cannot; the field has largely
abandoned this approach as unproductive and unresolvable. One thing
these arguments do demonstrate is that all primates are facultatively
bipedal. Some -- the living hominoids -- are more so than others; and
the anatomical shift to obligate bipedalism is not as huge a hurdle as
Morgan has made it out to be.

You say "more recently wading can be added to the list" - and that's been true since the Doran & McNeilage papers on Gorilla about 14 years ago, at least. However, I don't see the wading idea being represented in university level texts any more than it always has - usually as a kind of tongue-in-cheek "joke" at the end of the discussion. It's still sneered at because of its association with the so-called "aquatic ape" theory which, thanks to people like you, has been placed in the same "crazy box" as ideas like Von Daniken. If Hunt's study had been of bonobos in Lomoko, rather than of chimps in the Gombe - he'd have had a very different result and wading would probably have topped his list by a mile. Hunt's basic premise - that contexts of bipedalism in extant apes offer clues to our bipedal origins is still a valid one and certainly one of the least anthropocentric. Wading is by far the best published idea on that score because it most predictably induces bipedalism in otherwise quadrupedal apes. It's at least as good an idea as the others and is arguably far better for several reasons, as laid out in my meta analysis paper. The discrepancy between the high potential value of the idea and the tiny amount of attention it has attracted from the field is simply astonishing (and very disappointing) to me. I simply don't see how that discrepancy can be justified. It's basically down to sneer pressure.

If the field have "moved on" from Hunt's premise, it's all the more sad. I would suggest that it's simply because they have not fully considered the wading evidence. John, I thought that in science progress is made through the literature, though empirical studies. Perhaps then, you could cite me that paper where the wading hypothesis was considered (let alone rejected). See, I just don't think there is one. Your two para dismissal of Morgan's single point on the idea - it seems - is all there is in the 1st class literature on the subject! How on earth can you defend this and excuse the field for "moving on" when it's never even been properly looked at?

On your definitive test: "Place a group of otherwise quadrupedal apes in
scenario x, and watch them all switch to unsupported, bipedal locomotion
(not just a transitional posture) for as long as the scenario prevails.
Which scenario would kill them, if they were to continue to move
quadrupedally?" Quadrupedal or bipedal animals in water either stay in
the shallows or swim. They are not going to wait until the water comes
over their heads and drown and they are not going to become dependent on
resources they cannot access. This is a preposterous scenario and it
presupposes rather than demonstrates an aquatic niche.

The part about them drowning if they stayed quadrupedal is theoretical, of course. I'm not seriously suggesting they ever would. The fact you call that part of the scenario preposterous does not make the rest of it any less valid. What other scenario will induce bipedal locomotion (not just momentary posture) so predictably and for such a stretch of time in otherwise quadrupedal apes? I notice you didn't offer an alternative suggestion - because there isn't one. The fact is that even humans prefer to wade in depths of water in which they could theoretically swim - it's easier and safer. No other mammalian taxa (other than large primates) switch from quadrupedalism on dry land to bipedalism in shallow water like this and yet it has still been all but ignored for decades by the field. It's a no brainer.

This brings us back to my argument that the AAH is a paradigm -- a set
of prior assumptions made before the questions are asked. If you support
those assumptions (about aquatic commitment) by conjectures that assume
them (e.g., bipedalism), the reasoning is circular. [Now I rather wish I
had used the language of paradigm than coin the term 'umbrella hypothesis'.]

Ok, so what's the alternative, current paradigm? You guys have had about 150 years to think of one. Come on, John: Can you lay out how orthodox paleoanthropology explains the human phenotypic divergence from the others apes, in a single, simple sentence?

See, some of us can: 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.

Don't tell me. Suddenly, simplicity and parsimony are not desired attributes. How did you put it in your paper? When challenged for an alternative, all of a sudden, you say we should look for complex (not simple) stories with weak (not strong) plots. So much for parsimony!

On focusing on Morgan. You continue to criticize me for addressing only
Morgan's version of the AAH. I recognized in my paper, as I do now, that
others were making contributions; but honestly, Algis, how may other
versions were developed comprehensively in print in 1997? How many now?
I am aware of Verhaegen's later one but I won't pretend to read his book
in Dutch. Others, like Cunane, spin off from the AAH, but do not have a
fully developed version. Most of you -- yourself included -- focus on a
small cluster of attributes and by implication accept Morgan's more
completely articulated scenario to fill it out. I repeat that the
changes you have made -- moving from a fully aquatic life to merely
wading had torn the guts out of the original AAH so that it is now much
weaker in terms of explanatory power than it was. It waffles
inconsistently between merely wading and a vital dependence on swimming
and diving and presents a moving target. Even your emails do that. If
you really try to spell out your model and articulate the hypotheses it
uses for each trait it is trying to explain, I think you will see that.

Derek Ellis published papers in 1986, 1987, 1991, 1993 and 1995 extolling a very reasonable, evidence based idea for a "wetland ape" (an idea I have always thought was probably closer to the mark than the Hardy/Morgan formulation) - all before your "rebuttal".The only mention of him, however, was in your one,tiny, passing mention to the Valkenburg symposium.

If you'd have read his work and reported it fairly, you would have had to take on board the sort of "watered down" version you seem to want to dismiss as "Not the AAT". I dispute that Morgan had a completely articulated scenario. Hardy and Morgan basically asked a series of questions: Why are we so different from the other apes, considering we are so genetically close? Is there an adaptive scenario that could explain it? Could being "More aquatic" in the past do that? They proposed their own views on timescale, ecology, habitat and the degree of aquatic adaptation etc, but basically left it as an open ended question for others to follow up on.

You criticise us for "not having a fully developed version" and yet you seem reluctant to even articulate a sentence to describe what the orthodox view on this matter is. Double standards, or what?

You seem to suggest that being modest and realistic about the idea rather than exaggerating it, weakens it, but I think this is just posturing on your part. It's not "merely wading", it's wading-climbing leading to early bipedalism and then, when we came down from the trees, living in waterside habitats (as largely terrestrial animals) doing sufficient swimming and diving to effect our phenotype. I repeat my previous point that - since the out of Africa diaspora human populations have diverged in ca 80Ka in many ways due to a slight shift away from the equator, a slight shift to higher altitudes, or even drinking more milk. No-one would question this, so why is the concept that our ancestors doing (even slightly) more swimming and diving than the ancestors of chimps - over 5 million years or so, not be expected to make even more fundamental changes? Why not? Apart from personal incredulity and a reluctance to admitting that the entire field might have simply goofed on this for 50 years - what possible argument could you have?

On recurring themes. Yes there are recurring themes. I wrote my 1997
paper on Morgan's model drawn from all her writings at the time because
I recognize the problem of picking and choosing arguments from different
authors. I don't think I exaggerated it to ridiculous levels and I do
think you are revising what they wrote after the fact and, at the same
time, criticizing me for not addressing models that had not been
articulated before 1997. In your revision, you are hanging on to
arguments that were logically coherent for a fully aquatic phase, but at
the same time denying that phase.

To pick just one, stand-out example, your table 1 (p488), a number of times, states "Not typical of aquatic mammals" but you do not cite any "aquatic ape" proponent that suggests our ancestors ever were. This is a straw man argument, John. It's what you accused Elaine Morgan of doing with the savananh theory(!) when she absolutely did not - and yet you do worse throughout the whole paper. That it passed through peer review at JHE says a lot about the amount of critical thinking going in places of authority on this idea. Leslie Aiello (who was one of the editors at the time) referred me to your paper. I'd already read it and told her my severe criticisms, so guess what she did next? Referred me to Jim Moore's web site! Can you imagine any other scientific field where a professor and head of a department at a top university refers a student to a layman's gossipy web site to refute a really good idea? It's a scandal of Piltdown proportions, John.

Please tell me one argument that you think I am "hanging on to" that requires a "fully aquatic phase". That is simple a total misconception.

I am really trying to understand what you propose now, but I admit I
have to fill in with what was written in the past. Do I understand that
your current argument can be summarized by "our modern
swimming/wading/diving ability has been selected for because of our
dependency on a semi-aquatic niche"? That is not at all what Morgan
argued. She was quite explicit, as was Hardy's title, that we are less
adapted for water now than we used to be. For example, Morgan proposed
traits, such as a nasal sphincter, that doesn't exist any more. If that
is indeed what you intend, then any attempt to articulate it that refers
to previous models will fail -- it will be forever confused with them.

My interpretation of Morgan's work was clearly different from yours. This is a point I made earlier. Those who exaggerate the idea will obviously be more likely to sneer at it, whereas those who see it as slight shift in locomotor repertoire cannot see what the fuss is about. I made this point twice before - about Colin Groves review of Roede et al - but you seem to be avoiding it, John. Why's that?

We can all pick out our favourite word combos that "prove" the point we want to make but a more rational approach is to ask: could these ideas still work if the amount of adaptation was far less? I think the answer to that is very much "Yes!" You seem to think the answer is "No!" - this is the area where the debate should focus as we go forward from now on - exactly how much selection is needed for the kind of phenotypic changes being proposed? I am not a population geneticist but those who I have spoke to tell me the answer is "almost nothing".

s > 1/ (2Ne) [where s = selection; Ne = effective population size]

Put into simple terms, all other things being equal, if one individual per year drowned before reaching puberty in a population of a thousand individuals that regularly swam, one would expect any genes that made it less likely to drown to reach fixation in tens of thousands of years. This is the simple point everyone seems to have missed. Aquaskeptics have been too busy looking for fault or exaggerating the idea to breaking point to see that it's actually a potentially very helpful idea.

Why are we better swimmers? I won't disagree that we are better than
chimps. Many of the adaptations that we use for swimming clearly relate
to other activities: e.g., shoulder mobility and overhead reach to
climbing; our fully extended joints and weight distribution in the lower
limbs to bipedal walking/running; less dense bones for shock absorption;
possibly larger lungs for sustained endurance (that's my prediction, but
I have never seen measurements).

Er, chimps have better shoulder mobility than us, don't they? They still climb much more than us. If not, hey, maybe our increased shoulder mobility was due to swimming!
I think you're clutching at straws here, John. We have a whole host of traits that seem to indicate some aquatic adaptation and, guess what, we are better at swimming and diving than chimps... so what do we think?

Remember that term "parsimony"? How about this - the reason we are better at swimming than chimps - and not surprisingly, the reason we also have those traits - is because our ancestors did more swimming and diving than theirs.

Please provide a simpler (hence more parsimonious) explanation, or agree it should be the default assumption.

But I do believe our species' swimming ability is overrated. Is there
any species with a partially aquatic niche that that drowns as often as
humans? (My current research has me looking through death certificates
for a community in Indiana in the 1800s. I am surprised how many
children and adults drowned accidentally while bathing or crossing
rivers or falling off canal boats or even falling into a tub or cistern.
Anecdotal evidence is weak.) Is there any species with a partially
aquatic niche where a majority of its population never swims. (I can't
support that statement, but I believe it to be accurate.) Humans have to
learn and practice to in order to swim well.
So are we, as a species, truly good swimmers? I don't know how to
answer that. What would you expect "good" to mean in a species that has
been adapting to water since the Miocene? Perhaps not having to be face
down in the water so we can't breathe comfortably and swim at the same time.
Perhaps this difference in perspective on how important swimming is to
modern humans is fundamental to our disagreement. I don't perceive
humans today as semi-aquatic.

Straw man (again). The comparison that counts is with chimps and gorillas, not with "true aquatics", John.
As I said before the term "aquatic ape" was meant to be ironic: Of the apes (which we know are most definitely not aquatic) we are the most aquatic.

I find it very disappointing that this irony seems to have passed right over the heads of an entire field for 50 years.

If we're better at swimming and diving than chimps - and I think the vast bulk of evidence suggests we are - then that is really all waterside hypotheses propose. It's an exaggeration to suggest anything more.

They potentially help explain the way we are. Why are you opposed to that help? All we need is more open mindedness from the field and these ideas could be tested to see if they might be right.

All the best

Algis Kuliukas
CFS
UWA
Perth
Australia

[AlgisKuliukas]

John's reply [20 Jan 2012]

If the field have "moved on" from Hunt's premise, it's all the more sad. I would suggest that it's simply because they have not fully considered the wading evidence. John, I thought that in science progress is made through the literature, though emprical studies. Perhaps then, you could cite me that paper where the wading hypothesis was considered (let alone rejected). See, I just don't think there is one. Your two para dismissal of Morgan's single point on the idea - it seems - is all there is in the 1st class literature on the subject! How on earth can you defend this and excuse the field for "moving on" when it's never even been properly looked at?

First, the field has moved on for a good reason. The whole premise
behind Rose and Hunt's study is that baboons or chimps are good models
for out prebipedal ancestor. They are not.
Hominoid ancestors were adapted for climbing in ways that made them and
their descendents inefficient on the ground. They were poor quadrupedal
walkers, as all apes are today. Chimps knuckle-walk as an adaptive
strategy for ground travel with a suite of derived traits to facilitate
it. This is not a primitive condition. It does represent a compromise to
preserve limb proportions and long fingers and toes for climbing. I
would expect that if they needed to spend more time on the ground they
would increase the efficiency of their quadrupedalism.
For our pre-bipedal ancestor, I would look for a body form that did not
have a committed mode of ground travel. Gibbons don't. I don't suggest
that we are descended from brachiators specifically, but from climbers.
(I think this falls within Tuttle's hylobatian hypothesis.) Because of
its orthograde posture already developed for climbing, bipedalism was as
efficient (or more so) than quadrupedalism in any form. Increased time
on the ground led to selective pressure to increase the efficiency of
bipedalism. Bipedalism is best explained in the context of the prior
anatomy of our ancestors (Gould used the term "historical contingency"
for this concept). For this reason, looking to existing primates for
reasons to become bipedal is barking up the wrong tree.

And for the last time, I did not dismiss Morgan's argument on
bipedalism in two paragraphs. My purpose was not to dismiss or even to
evaluate her model; it was to show that her hypotheses could be matched
by plausible alternative models that did not involve the aquatic
scenario. Obviously you still don't understand my argument.

This brings us back to my argument that the AAH is a paradigm -- a set
of prior assumptions made before the questions are asked. If you support
those assumptions (about aquatic commitment) by conjectures that assume
them (e.g., bipedalism), the reasoning is circular. [Now I rather wish I
had used the language of paradigm than coin the term 'umbrella hypothesis'.]

Ok, so what's the alternative, current paradigm? You guys have had about 150 years to think of one. Come on, John: Can you lay out how orthodox paleoanthropology explains the human phenotypic divergence from the others apes, in a single, simple sentence?

I'll bite. My paradigmatic assumptions: Humans emerged from the
last common (hominoid climbing) ancestor in a process that involved a
gradual shift from predominantly arboreal to exclusively terrestrial
activity. Evidence suggests this happened in Africa between about 6 and
2 Mya.

From these assumptions we can build more specific hypotheses about the
selective pressures involved, the timing and sequence of acquisition of
derived traits, etc. I use the word terrestrial here to mean
non-arboreal. I believe that by 2.0 Mya, if not before, humans were
increasing their ecological breadth to exploit many subhabitats, very
likely including aquatic resources. However, I would distinguish this
argument from your model by saying there is no evidence that there was a
dependence on aquatic resources sufficient to significant selective
forces or shape anatomy.

The parallel statement for the AAH would be: Humans emerged from the
last common ancestor in a niche where they were dependent on
exploitation of aquatic resources. (I will let you fill in the time and
place.)

From those assumptions you construct more specific hypotheses about the
selective pressure involved, etc. Those hypotheses inevitably will make
the nature of interactions with aquatic resources more specific and
differentiate your model from that of Hardy and Morgan. Does that
reflect your position?

Which of these is more parsimonious? The first is more conservative
because it is more consistent with what we have observed about all other
primates, living or extinct. It involves fewer discontinuities of behavior.
However, one generally cannot attack a paradigm on its assumptions,
because those are assumed, not argued. You can like the assumptions or
not like them, as long as they are consistent with observations.
Criticism comes from debating generally untestable hypotheses about
selective forces and scenarios and from debating interpretations of
observations.

You criticise us for "not having a fully developed version" and yet you seem reluctant to even articulate a sentence to describe what the orthodox view on this matter is. Double standards, or what?

I didn't know you wanted me to, since there are many textbooks that
do. I put out my premise above and have stated many of my specific
arguments and hypotheses in my book. Is that reluctance or double standard?
And I am not criticizing you -- just explaining why I chose to discuss
Morgan. Since you have distanced yourself from her views, I obviously
would need to understand your model better before I could respond to it.
Nonetheless, the primary purpose of my publication (since you still
don't get it) was not to criticize all versions and twists of the AAH,
but to show that such approaches (umbrella hypotheses) do not possess
the parsimony claimed for them because all the "explanations" contained
within them are merely hypotheses with no more support for them or
certainty about them than more traditional hypotheses.

To pick just one, stand-out example, your table 1 (p488), a number of times, states "Not typical of aquatic mammals" but you do not cite any "aquatic ape" proponent that suggests our ancestors ever were.

Every feature listed in that table was drawn from Morgan's writings.

Please tell me one argument that you think I am "hanging on to" that requires a "fully aquatic phase". That is simple a total misconception.

I wrote previously:

I am really trying to understand what you propose now, but I admit I
have to fill in with what was written in the past.
You have indicated you believe the AAH explains lots of traits.
Just so I don't put words in your mouth that belong in Morgan's, what
are those traits? I don't want to argue traits and hypotheses unless I
know I am not misrepresenting your position.

Regards,
John

--
John H. Langdon

[AlgisKuliukas]

My reply [21 Jan 2012]

First, the field has moved on for a good reason. The whole premise
behind Rose and Hunt's study is that baboons or chimps are good models
for out prebipedal ancestor. They are not.

Well, they are the best available, given what we have. I think that is all Hunt etc. would ever claim.

Hominoid ancestors were adapted for climbing in ways that made them and
their descendents inefficient on the ground. They were poor quadrupedal
walkers, as all apes are today. Chimps knuckle-walk as an adaptive
strategy for ground travel with a suite of derived traits to facilitate
it. This is not a primitive condition. It does represent a compromise to
preserve limb proportions and long fingers and toes for climbing. I
would expect that if they needed to spend more time on the ground they
would increase the efficiency of their quadrupedalism.
For our pre-bipedal ancestor, I would look for a body form that did not
have a committed mode of ground travel. Gibbons don't. I don't suggest
that we are descended from brachiators specifically, but from climbers.
(I think this falls within Tuttle's hylobatian hypothesis.) Because of
its orthograde posture already developed for climbing, bipedalism was as
efficient (or more so) than quadrupedalism in any form. Increased time
on the ground led to selective pressure to increase the efficiency of
bipedalism. Bipedalism is best explained in the context of the prior
anatomy of our ancestors (Gould used the term "historical contingency"
for this concept). For this reason, looking to existing primates for
reasons to become bipedal is barking up the wrong tree.

This is an interesting conjecture, John. You might be right to support the hylobation model but you should know that it's a model the Marc Verhaegen has pretty much followed for years. The "aquarboreal" (wading-climbing) model - which I have followed too since Orrorin was discovered, but which Elaine still rails against - is very much predicated on the sort of vertical climbing you espouse here.

Clearly wading alone is not enough, otherwise we'd expect all wading mammals to be bipedal in water, when they aren't. Equally, vertical climbing ancestry is insufficient too, otherwise why are we he only obligate terrestrial bipedal primate? Unfortunately, we simply do not have a good candidate in the fossil record for the LCA (unless you know something I don't) so all this is conjecture anyway.

What seems clear to me now is that when postulating the LCA between two knuckle-walking quadrupeds and one obligate, striding biped it was naive to assume that they were knuckle-walking quadrupeds. It is equally naive to think they were bipedal like us, as seems to be de rigeur now, since Filler. Surely, something intermediate is more likely - something like a wading-climbing biped.

I notice you avoided my request to supply the citation of that paper where the wading idea has even been considered, let alone rejected. I don't blame you, it is quite embarrassing that such a simple idea has not attracted even a single paper (out of tens of thousands) in the last 50 years.

And for the last time, I did not dismiss Morgan's argument on
bipedalism in two paragraphs. My purpose was not to dismiss or even to
evaluate her model; it was to show that her hypotheses could be matched
by plausible alternative models that did not involve the aquatic
scenario. Obviously you still don't understand my argument.

John, whether you like it or not, your paper is seen as a rebuttal of the AAH. Ok, so you're saying it was not your intention to do that. Great, so can I now start claiming that there is not even one single attempt in the literature to reject ("or even to evaluate") this idea? not even yours? Blimey!!

If you are telling me that your two paras on the wading idea wasn't meant to constitute a critique of the idea - this hardly makes the aquaskeptic position stronger. Please, let's be clear on this because I wouldn't want to be accused of twisting anyone's words - are you saying that there is, in fact, not even one attempt at a rebuttal of the so-called "aquatic ape" in a 1st class anthro journal? Because I'd be quite happy to start claiming that, if you agree.

I thought only one in 50 years was bad - but zero is even worse!

I'll bite. My paradigmatic assumptions: Humans emerged from the
last common (hominoid climbing) ancestor in a process that involved a
gradual shift from predominantly arboreal to exclusively terrestrial
activity. Evidence suggests this happened in Africa between about 6 and
2 Mya.
From these assumptions we can build more specific hypotheses about the
selective pressures involved, the timing and sequence of acquisition of
derived traits, etc. I use the word terrestrial here to mean
non-arboreal. I believe that by 2.0 Mya, if not before, humans were
increasing their ecological breadth to exploit many subhabitats, very
likely including aquatic resources. However, I would distinguish this
argument from your model by saying there is no evidence that there was a
dependence on aquatic resources sufficient to significant selective
forces or shape anatomy.

That's fine, I suppose. We can quibble over what you mean by "sufficient" later.

The parallel statement for the AAH would be: Humans emerged from the
last common ancestor in a niche where they were dependent on
exploitation of aquatic resources. (I will let you fill in the time and
place.)

This is a little binary to me. I think you're exaggerating again. I think it is tendency aquaskeptics can't resist because it's the easy option. Why not simply postulate "more dependent on than their great ape cousins". It's not 'A' or 'B', 0 or 1, "aquatic" or "terrestrial". It's a matter of degree.

From those assumptions you construct more specific hypotheses about the
selective pressure involved, etc. Those hypotheses inevitably will make
the nature of interactions with aquatic resources more specific and
differentiate your model from that of Hardy and Morgan. Does that
reflect your position?

Yes, pretty much.

Which of these is more parsimonious? The first is more conservative
because it is more consistent with what we have observed about all other
primates, living or extinct. It involves fewer discontinuities of behavior.
However, one generally cannot attack a paradigm on its assumptions,
because those are assumed, not argued. You can like the assumptions or
not like them, as long as they are consistent with observations.
Criticism comes from debating generally untestable hypotheses about
selective forces and scenarios and from debating interpretations of
observations.

Well if you're postulating that these hominids just came down from the trees and lived in the same sort of habitat as chimps and gorillas and other large Primates I'm yet to hear how this explains the remarkable divergence. It's so parsimonious it explains nothing. It basically says - what? shit happens? it was drift? How does this explain why we became obligate bipeds, but chimps became knuckle-walkers? How does it explain why we became naked, but they didn't? etc etc.

WHHE don't duck these issues, they make simple predictions that explain them - all of them, pretty much in one (ok, maybe two) fell swoop.

So to answer your question - WHHE are more parsimonious - by a mile.

I didn't know you wanted me to, since there are many textbooks that
do. I put out my premise above and have stated many of my specific
arguments and hypotheses in my book. Is that reluctance or double standard?
And I am not criticizing you -- just explaining why I chose to discuss
Morgan. Since you have distanced yourself from her views, I obviously
would need to understand your model better before I could respond to it.
Nonetheless, the primary purpose of my publication (since you still
don't get it) was not to criticize all versions and twists of the AAH,
but to show that such approaches (umbrella hypotheses) do not possess
the parsimony claimed for them because all the "explanations" contained
within them are merely hypotheses with no more support for them or
certainty about them than more traditional hypotheses.

Really? I must have missed them. One minute we are being told the savannah theory was all a straw man invention by Elaine Morgan - even though practically every text book on the subject in the last 60 years makes the implicit or explicit assumption that a move to open habitats played a key part in human evolution. Next minute we evolved in the same place as chimps. Which do you prefer today?

So are you really saying that there is no "AAH" rebuttal in the anthro literature? Really?

Every feature listed in that table was drawn from Morgan's writings.

Ok, but writing "not typical of aquatic mammals" shows you're making comparisons with dolphins, rather than with chimps. I argue that's a straw man argument. It's as much a straw man, in any case, as the claim aquaskeptics make when Morgan compares humans with savannah mammals.

I wrote previously:
> JL: I am really trying to understand what you propose now, but I admit I
> have to fill in with what was written in the past.

JL2: You have indicated you believe the AAH explains lots of traits.
Just so I don't put words in your mouth that belong in Morgan's, what
are those traits? I don't want to argue traits and hypotheses unless I
know I am not misrepresenting your position.

The phenotypic differences between us and chimps/gorilla. Bipedalism, body hair pattern, increased adipocity esp. in infants/women, changes to breathing aparatus, improved voluntary breath control, encephalisation - pretty much all of them. I cannot think of one physical difference between humans and chimps/gorillas that is not at least helped by postulating some selection from wading, swimming and diving. Maybe you could help me there.

I have to ask you one direct question here, John, as you seem to be avoiding commenting on them. What say you about Derek Ellis' take on all this? What about Colin Groves' review of Roede et al? How come they skipped your attention? You have to admit they have a different take on it from the "full on aquatic" idea you critiqued.

Algis Kuliukas
CFS
UWA
Perth

[AlgisKuliukas]

John Langdon's reply [22 Jan 2012]

Just to remind... I'm posting these here because...

a) I think the discussion should be in the public domain.
b) John gave me permission to do so.

> First, the field has moved on for a good reason. The whole premise
> behind Rose and Hunt's study is that baboons or chimps are good models
> for out prebipedal ancestor. They are not.

>
> AK: Well, they are the best available, given what we have. I think that is all Hunt etc would ever claim.

JL3: But that does not make them appropriate.

> Hominoid ancestors were adapted for climbing in ways that made them and
> their descendents inefficient on the ground. They were poor quadrupedal
> walkers, as all apes are today. Chimps knuckle-walk as an adaptive
> strategy for ground travel with a suite of derived traits to facilitate
> it. This is not a primitive condition. It does represent a compromise to
> preserve limb proportions and long fingers and toes for climbing. I
> would expect that if they needed to spend more time on the ground they
> would increase the efficiency of their quadrupedalism.
> For our pre-bipedal ancestor, I would look for a body form that did not
> have a committed mode of ground travel. Gibbons don't. I don't suggest
> that we are descended from brachiators specifically, but from climbers.
> (I think this falls within Tuttle's hylobatian hypothesis.) Because of
> its orthograde posture already developed for climbing, bipedalism was as
> efficient (or more so) than quadrupedalism in any form. Increased time
> on the ground led to selective pressure to increase the efficiency of
> bipedalism. Bipedalism is best explained in the context of the prior
> anatomy of our ancestors (Gould used the term "historical contingency"
> for this concept). For this reason, looking to existing primates for
> reasons to become bipedal is barking up the wrong tree.

>
> AK: This is an interesting conjecture, John. You might be right to support the hylobation model but you should know that it's a model the Marc Verhaegen has pretty much followed for years. The "aquarboreal" (wading-climbing) model - which I have followed too since Orrorin was discovered, but which Elaine still rails against - is very much predicated on the sort of vertical climbing you espouse here.
>
> AK: Clearly wading alone is not enough, otherwise we'd expect all wading mammals to be bipedal in water, when they aren't. Equally, vertical climbing ancestry is insufficient too, otherwise why are we he only obligate terrestrial bipedal primate? Unfortunately, we simply do not have a good candidate in the fossil record for the LCA (unless you know something I don't) so all this is conjecture anyway.

JL3: ". . . so all this is conjecture anyway." That describes all discussion of evolutionary scenarios.

> AK: What seems clear to me now is that when postulating the LCA between two knuckle-walking quadrupeds and one obligate, striding biped it was naive to assume that they were knuckle-walking quadrupeds. It is equally naive to think they were bipedal like us, as seems to be de rigeur now, since Filler. Surely, something intermediate is more likely - something like a wading-climbing biped.
It is naive to think that the LCA was an obligate biped. But since all primates are facultative bipeds and the African hominoids appear to be more comfortable in that posture than any other higher primates, the LCA was probably frequently a biped.
> AK: I notice you avoided my request to supply the citation of that paper where the wading idea has even been considered, let alone rejected. I don't blame you, it is quite embarrassing that such a simple idea has not attracted even a single paper (out of tens of thousands) in the last 50 years.

JL3: If it has not been discussed, I can't argue with you about it. Why has it been ignored? Many evolutionay scenarios (conjectures) are offered, but unless anthropologists find them really compelling they get ignored. That includes mose terrestrial scenarios. Kingdon, a respected expert on African mammals, wrote a whole book promoting his idea. I can't even remember what it was. Aside from a couple of book reviews I have never seen it cited. Nina Jablonski, is a prolific publisher in anthropology, She wrote an article in JHE on a sexual selection hypothesis for bipedalism and a book on skin coloration. I have never seen either discussed in the literature. Beyond a debate along the lines of "I think hypothesis A is more reasonable." "No, I think B is better." Unless someone can find a new way to generate evidnece, there simply is not much to say about evolutionary conjectures.
Consider David Horrobin's journal Medical Hypotheses. Every month a couple of dozen ideas are published -- well reasoned but unsupported by critical study. I am sure the authors feel passionately about their ideas; but I am also sure 90% of them are completely ignored.

> JL2: And for the last time, I did not dismiss Morgan's argument on
> bipedalism in two paragraphs. My purpose was not to dismiss or even to
> evaluate her model; it was to show that her hypotheses could be matched
> by plausible alternative models that did not involve the aquatic
> scenario. Obviously you still don't understand my argument.

>
> AK: John, whether you like it or not, your paper is seen as a rebuttal of the AAH. Ok, so you're saying it was not your intention to do that. Great, so can I now start claiming that there is not even one single attempt in the literature to reject ("or even to evaluate") this idea? not even yours? Blimey!!
>
> AK: If you are telling me that your two paras on the wading idea wasn't meant to constitute a critique of the idea - this hardly makes the aquaskeptic position stronger. Please, let's be clear on this because I wouldn't want to be accused of twisting anyone's words - are you saying that there is, in fact, not even one attempt at a rebuttal of the so-called "aquatic ape" in a 1st class anthro journal? Because I'd be quite happy to start claiming that, if you agree.

JL3: Once more, my argument is that there are multiple hypotheses about bipedalism (and other features) most of which cannot be directly tested or disproved. (Some, however, are clearly weaker than others.) In the case of the examples presented in my article, they depend on different starting assumptions (umbrellas, paradigms). The assumptions themselves to not confer parsimony; but some assumptions are more parsimonious than others. I do think the AAH is unparsimonious and weak in its initial assumptions for reasons stated in the article.
I did not try to evaluate most of the specific hypotheses; however, in rejecting the starting assumptions of the AAH, I believe they are rendered useless.

> JL2: I'll bite. My paradigmatic assumptions: Humans emerged from the
> last common (hominoid climbing) ancestor in a process that involved a
> gradual shift from predominantly arboreal to exclusively terrestrial
> activity. Evidence suggests this happened in Africa between about 6 and
> 2 Mya.
> From these assumptions we can build more specific hypotheses about the
> selective pressures involved, the timing and sequence of acquisition of
> derived traits, etc. I use the word terrestrial here to mean
> non-arboreal. I believe that by 2.0 Mya, if not before, humans were
> increasing their ecological breadth to exploit many subhabitats, very
> likely including aquatic resources. However, I would distinguish this
> argument from your model by saying there is no evidence that there was a
> dependence on aquatic resources sufficient to significant selective
> forces or shape anatomy.

>

> AK: That's fine, I suppose. We can quibble over what you mean by "sufficient" later.
>

> JL2: The parallel statement for the AAH would be: Humans emerged from the
> last common ancestor in a niche where they were dependent on
> exploitation of aquatic resources. (I will let you fill in the time and
> place.)

>
> AK: This is a little binary to me. I think you're exaggerating again. I think it is tendency aquaskeptics can't resist because it's the easy option. Why not simply postulate "more dependent on than their great ape cousins". It's not 'A' or 'B', 0 or 1, "aquatic" or "terrestrial". It's a matter of degree.

L3: Natural selection won't operate on a species to procure resources that are not essential, because individuals who fail to obtain them will not be at a disadvantage. This goes with the definition of essential. IT also addresses your hesitation about "sufficient dependence" above.

> JL2: From those assumptions you construct more specific hypotheses about the
> selective pressure involved, etc. Those hypotheses inevitably will make
> the nature of interactions with aquatic resources more specific and
> differentiate your model from that of Hardy and Morgan. Does that
> reflect your position?

>
> AK: Yes, pretty much.
>

> JL2: Which of these is more parsimonious? The first is more conservative
> because it is more consistent with what we have observed about all other
> primates, living or extinct. It involves fewer discontinuities of behavior.
> However, one generally cannot attack a paradigm on its assumptions,
> because those are assumed, not argued. You can like the assumptions or
> not like them, as long as they are consistent with observations.
> Criticism comes from debating generally untestable hypotheses about
> selective forces and scenarios and from debating interpretations of
> observations.

>
> AK: Well if you're postulating that these hominids just came down from the trees and lived in the same sort of habitat as chimps and gorillas and other large Primates I'm yet to hear how this explains the remarkable divergence. It's so parsimonious it explains nothing. It basically says - what? shit happens? it was drift? How does this explain why we became obligate bipeds, but chimps became knuckle-walkers? How does it explain why we became naked, but they didn't? etc etc.

JL3: Did they live in the same sort of habitat as chimps and gorillas? We don't know since we have not been able to reconstruct the habitats in sufficient detail for the earliest hominins. In fact, as you know, the fossil record is pretty bleak before australopithecines. Since we do not have a fossil record at all, to speak of, for chimps and gorillas, we don't have any information about the habitat of their ancestors. Since we have not found fossils apes and fossil hominins together, there may well have been a significant habitat separation.
Yves Coppens ("East Side Story") created a scenario in which chimp and human ancestors were stuck on different sides of the Rift and then went their different merry ways. There are problems with the details of his version, but basic premise of a geographic divide seems reasonable if unproven.

> AK: WHHE don't duck these issues, they make simple predictions that explain them - all of them, pretty much in one (ok, maybe two) fell swoop.

> AK: So to answer your question - WHHE are more parsimonious - by a mile.
WHHE does not explain them. It offers a set of assumptions from which you can construct more hypotheses. That is not a quibble, but a critical distinction.

> JL2: I didn't know you wanted me to, since there are many textbooks that
> do. I put out my premise above and have stated many of my specific
> arguments and hypotheses in my book. Is that reluctance or double standard?
> And I am not criticizing you -- just explaining why I chose to discuss
> Morgan. Since you have distanced yourself from her views, I obviously
> would need to understand your model better before I could respond to it.
> Nonetheless, the primary purpose of my publication (since you still
> don't get it) was not to criticize all versions and twists of the AAH,
> but to show that such approaches (umbrella hypotheses) do not possess
> the parsimony claimed for them because all the "explanations" contained
> within them are merely hypotheses with no more support for them or
> certainty about them than more traditional hypotheses.

>
> AK: Really? I must have missed them. One minute we are being told the savannah theory was all a straw man invention by Elaine Morgan - even though practically every text book on the subject in the last 60 years makes the implicit or explicit assumption that a move to open habitats played a key part in human evolution. Next minute we evolved in the same place as chimps. Which do you prefer today?

JL3: I'm not sure I follow you because I think you are deliberately distorting things. I make a distinction between the Savanna Theory (which I previously denied existed and Morgan rightly criticizes) and a savanna setting for evolution. The Theory was an intellectually lazy assumption that merely changing habitats led to the evolution of certain traits. That is very different from an assertion that certain stages of human evolution occurred in a savannah setting and we can construct hypotheses why certain traits emerged in that context. Paleoenvironmental evidence can now link the emergence of Homo to a more open habitat, but older hominins are still associated with a more closed one. We have gotten more cautious (sophisticated?) about stating everything as either or forest or savanna, recognizing that habitats are more complex. I can show you pictures I took in Kenya in 1980 on a savanna showing greatly different levels of tree cover with a few miles of each other. I know of one study site of chimps living on a savanna in West Africa.

> AK: Ok, but writing "not typical of aquatic mammals" shows you're making comparisons with dolphins, rather than with chimps. I argue that's a straw man argument. It's as much a straw man, in any case, as the claim aquaskeptics make when Morgan compares humans with savanah mammals.

JH3: What trait(s) are you referring to? The two I identified on the chart that way are not present in dolphins:
bipedalism -- Do you have any other examples of aquatic bipeds, aside from penguins that were already bipedal?
speech -- Do you have any other examples of speaking aquatic mammals? (note that was a separate trait from complex vocalizations)

JH3: The traits that really might be compared with dolphins I listed as follows:
breath holding -- primary evidence
complex vocalizations -- parallelism
enlarged pharynx -- primary evidence
respiratory valves -- hypothetical trait
body hair reduction -- part of a thermoregulatory strategy
subcutaneous fat -- part of a thermoregulatory strategy [I would change this now -- I don't see it as part of the human thermoregulatory strategy.]
frontal sex -- secondary to bipedalism
enlarged brain -- parallelism
(By the way, when I described traits as primary evidence, consistent with AAH, or hypothetical, I was trying to infer Morgan's use of the trait.)
If you don't want to use cetacean models for your version of the WHHE, than there is no comparative anatomical support for including complex vocalizations, enlarged pharynx, hair reduction, fat, or enlarged brain as evidence for your model. This is exactly why I asked you to spell out which traits you think your WHHE explains and the evidence for that is. I don't think the WHHE can be as strong as the AAH without the cetacean analogies

> JL2: I wrote previously:
>> JL: I am really trying to understand what you propose now, but I admit I
>> have to fill in with what was written in the past.
> JL2: You have indicated you believe the AAH explains lots of traits.
> Just so I don't put words in your mouth that belong in Morgan's, what
> are those traits? I don't want to argue traits and hypotheses unless I
> know I am not misrepresenting your position.

>
> AK: The phenotypic differences between us and chimps/gorilla. Bipedalism, body hair pattern, increased adipocity esp. in infants/women, changes to breathing aparatus, improved voluntary breath control, encephalisation - pretty much all of them. I cannot think of one physical difference between humans and chimps/gorillas that is not at least helped by postulating some selection from wading, swimming and diving. Maybe you could help me there.

JH3: You listed 6 specific traits (I will overlook "pretty much all of them".) Again, to avoid putting Morgan's words in your mouth, what are your hypotheses for how/why those traits evolved and your arguments supporting the hypotheses?
From your paper I assume your bipedalism hypothesis is that our ancestors (which and when?) found it necessary to wade (for foraging?) and that bipedal locomotion increased their efficiency in doing so. Is that correct? (If so, is that really better than "they found it necessary to forage more on the ground and since they were poor quadrupeds increased their efficiency by being bipedal?")
How about the others? I would like to see them all so I can get a better understanding of how you reconstruct our ancestors and their relationship to water. But I also don't think they will make a coherent model.

> AK: I have to ask you one direct question here, John, as you seem to be avoiding commenting on them. What say you about Derek Ellis' take on all this? What about Colin Groves' review of Roede et al? How come they skipped your attention? You have to admit they have a different take on it from the "full on aquatic" idea you critiqued.
>

JL3: Honestly, I have not reread that volume since I wrote my paper 15 years ago. I don't own a copy, but obtained it at the time from interlibrary loan. I don't remember them enough to comment. I will not argue that they may have a different take, but what is your point? You stated that Groves argued it would be unfair for me to pick and choose among different authors to critique. I agreed and I didn't. I never pretended to discuss all models. (That didn't stop Morgan from trying to generalize about all terrestrial models under the distortion "Savannah Theory.")