Thread: We're bipedal because of (semi)aquatic ancestors? [Aquatic Ape Theory]

I'd never heard of the "Auqatic Ape" theory until Elaine Morgan disgussed it on a show I was watching. The argument is compelling, it states that man has qualities that are shared only with other aquatic mammals - not the other primates or even great apes.
1. Hairlessness and a more "streamline" shape
2. A layer of fat under the skin
3. The ability to control breath intake-thus ability to speak
4. Dilute Urine
5. Stretched hindlimbs
6. The ability to swim
7. And the fact that all apes walk on two legs when going through water
I definately thinks it's interesting and thought-provoking, but I personally don't believe it because everything mentioned above can also be explained using more accepted theories...And I'll be the first to admit I'd rather stick to what I know.
What does everyone else think?

I had her book back in the 70s. Thought provoking, yes. Convincing, not very.

We've just finished a tv series from Dr Alice Roberts The Origins of Us here. She's comparable because she's an anatomist.

My feeling is that the breathing and hindlimbs features are better explained by running - not just walking - than swimming.

That layer of fat idea doesn't work for me as an aquatic feature. If it were true, some significant portion of the population would show a useful tendency to accumulate fat under the skin, all over the body. What we see is an assortment of processes in various people, some in lower limbs or upper limbs, many people accumulate fat almost invisibly throughout the torso around the organs, other invisible accumulations happen throughout the circulation system.

The hairlessness ? It's furlessness, surely. Doesn't really work for me either. Seems to contradict the fat idea.
A truly aquatic mammal that started out with some fur would surely develop thicker water repellent fur - just look at seals, they have both blubber and fur. Then there are otters, platypus, walrus.

I think the much better explanation is our intelligence, flexibility and versatility. Apart from Antarctica, we can occupy any ecological niche anywhere in the world. Starting out versatile and getting more and more so is, apart from any other consideration, a much more logical notion than starting out as an ape, who specialises for water, then diversifies back to even more diversity.

Humans have developed the ability to teach children many things, swimming being one of them, just as notable is the inherent ability to climb and dig.

If you have a month to spare, you can read the beating a dead horse disussion in this thread:

Aquatic Ape Hypothesis

if you have a month to spare,

rofl

OK. You made me look.

977 comments!! I don't think I'll bother if the first page is anything to go by.

Originally Posted by Supervixen

1. Hairlessness and a more "streamline" shape
2. A layer of fat under the skin
3. The ability to control breath intake-thus ability to speak
4. Dilute Urine
5. Stretched hindlimbs
6. The ability to swim
7. And the fact that all apes walk on two legs when going through water
I definately thinks it's interesting and thought-provoking, but I personally don't believe it because everything mentioned above can also be explained using more accepted theories...And I'll be the first to admit I'd rather stick to what I know.
What does everyone else think?

1. Not hairless, and our actual hair characteristics are not shared with any semiaquatic mammal; shape not more streamlined.
2. Our fat characteristics are the same as other primates when they overeat like we do.
3. Same as a host of non-aquatic mammals, and any improved ability we have in regard to breathe control is due to our bipedalism, as shown by studies of locomotion and breathing (the muscles surrounding our forelimbs are largely decoupled from locomotion, freeing our breathing).
4. Urine dilute compared to what? BTW, marine mammals generally less dilute, urine-wise.
5. Which is the opposite of semiaquatic mammals, and the opposite of how they've diverged from their terrestrial relatives.
6. We are one of the few mammals which lack an instinctive ability to swim (African apes and giraffes are only the others I know of).
7. Simply false, and the AAT/H proponents, Morgan in particular, making this statement know it is false, which means they are knowlingly lying to you when they tell you that.

So all 7 of these "arguments" are simply false. What's more, the proponents of the idea have been informed that these claims are false, many times. Which means they are lying to you when they told you these are good arguments. There's a good reason the thread here got moved into Pseudoscience.

It is, however, a very fun theory. AAH proponents over reach with their arguments, much like how Bible thumpers tend to overreach in their arguments to prove there is a God. Their main problem is they.

1) - Use lots of evidence that doesn't prove their point anyway (as anthrosciguy pointed out)

2) - Try to explain too much from it.

If we really want to discuss it, we'd have to discuss lighter versions of the theory, like where a wading period plays some kind of role, but other things contribute also. Like a wading period could have helped us develop running stamina, or better eyesight or something, which then leads us to go back on land and develop the rest. That's more plausible. Trying to trace everything back to a single source smacks of storybook fantasy. Real life is rarely so simple or one dimensional.

Originally Posted by adelady

My feeling is that the breathing and hindlimbs features are better explained by running - not just walking - than swimming.

You have to be bipedal in the first place, to run - efficiently and structurally bipedal. That's the central problem of human evolution.

Whatever else is said about the AAH, there is currently no better supported or more plausible hypothesis (and many well-respected but much worse, some to the point of comical) to account for that radical development. Nothing else so far proposed gets a quadrupedal ape (no tools to carry, no strange breathing to abet, etc) up on its hind legs and keeps it there for hours engaged in critical tasks - that alone should ensure that it is discussed with ordinary courtesy and interest.

Originally Posted by kojax

1) - Use lots of evidence that doesn't prove their point anyway (as anthrosciguy pointed out)

2) - Try to explain too much from it.

Trying to explain too much - especially things like hairlessness that have better explanations - is indeed a fault of the AAH crownd as a whole.

But that observation does not invalidate - or even cast doubt on - the basic hypothesis.

As far as anthrosciguy's "contribution" - let's go through it:

1. Not hairless, and our actual hair characteristics are not shared with any semiaquatic mammal; shape not more streamlined.
2. Our fat characteristics are the same as other primates when they overeat like we do.
3. Same as a host of non-aquatic mammals, and any improved ability we have in regard to breathe control is due to our bipedalism, as shown by studies of locomotion and breathing (the muscles surrounding our forelimbs are largely decoupled from locomotion, freeing our breathing).
4. Urine dilute compared to what? BTW, marine mammals generally less dilute, urine-wise.
5. Which is the opposite of semiaquatic mammals, and the opposite of how they've diverged from their terrestrial relatives.
6. We are one of the few mammals which lack an instinctive ability to swim (African apes and giraffes are only the others I know of).
7. Simply false, and the AAT/H proponents, Morgan in particular, making this statement know it is false, which means they are knowlingly lying to you when they tell you that.

1) correct in general, but overlooks fat layer - and the observation about "streamlined" is irrelevant and strange.
2) This is false. Ordinarily fed humans have a fat layer no other primate possesses, and resemble other healthy primates only when severely malnourished. This is especially visible in infants.
3) This is false - the human setup is quite odd, not the best for running (nasal passages constricted, obstacles in windpipe), develops only after birth, and once developed carries extra risks (such as choking on one's food, having it "go down the wrong pipe", etc). Human breath control is aided - partly - by decoupled forelimbs - but this bipedalism remains unaccounted for, and all its features likewise. Running does not explain even this part of the human breath control setup.
4) Granted. So what?
5) But perfectly reasonable as primate adaptations to wading, as with other wade-foraging animals.
6) We lack an instinctive ability to do much of anything, for developmental reasons - but we have an instinctive ability to learn some things easily and well and are attracted to them: wading/swimming is one of the earliest and easiest. Like ducks and raccoons, unlike chickens and cats, humans naturally play in the water as soon as they can for as long as they can. Infants can swim before they can walk.
7) Morgan and other AAH proponents do not make that statement - that "all apes" walk on two legs in water. And the argument does not depend on any such circumstance - if even one ape walks on two legs through water often and persistently, that particular AAH argument is made. And more than one does.

The quick resort to calling people liars and other aspersions, without getting the facts straight, is common among AAH critics. Numerous examples are visible in the other thread.

Originally Posted by kojax

If we really want to discuss it, we'd have to discuss lighter versions of the theory, like where a wading period plays some kind of role, but other things contribute also. Like a wading period could have helped us develop running stamina, or better eyesight or something, which then leads us to go back on land and develop the rest. That's more plausible.

That's just what the people who wanted to discuss the hypothesis in the other thread were trying to do. I direct your attention to the response of the moderation team to that completely reasonable matter of discussion. It's where I learned the nature of the moderation of this forum, which is fully on display in that thread.

False dichotomy. Sad watching people on either side ritualistically trolling each other. They're like arguing whether opposable thumbs are for grasping stones or grasping sticks. But in evolution: the more advantages, the better.

Anyway I've found not drowning in water to be advantageous.

1. I understand the Argument from Authority fallacy.
2. I admire David Attenborough.
3. David Attenborough has strong inlicnations to accept the hypothesis
4. I ignore point 1.
5. I have strong inclinations to accept the hypothesis

Originally Posted by pong

False dichotomy. Sad watching people on either side ritualistically trolling each other. They're like arguing whether opposable thumbs are for grasping stones or grasping sticks. But in evolution: the more advantages, the better.

There aren't two sides, a dichotomy, or any equivalencies in trolling.

There are people who consistently support blatant and repeated trolling in the matter, like this guy:

Lynx_Fox likes this.

, and there are people capable of reasonable discussion in this matter. Those aren't "two sides" of anything.

If you try to lay out the dichotomy you pretend to refer to, rather than resort to the grasping thumb "analogy", you'll find yourself unable to - the problem of finding and explicating any advantages at all, not choosing between two sets, is central here.

The transition to bipedal walking involved overcoming the serious handicaps obvious in the transitional stages and forms, starting with a quadrupedal ape most often presumed to resemble current non-human apes. In evolution, the overcoming of such serious disadvantage requires explanation.

Interesting paper on the coevolution of human hands and feet: http://homepages.ucalgary.ca/~cproli.../Rolian10a.pdf

It raises a really interesting point, which would favor the savanna hypothesis. Think about it: You've got these apes no longer in the trees who now have to walk around on the ground. But their hands are still useful and increase locomotion is not enough of a benefit to justify losing them.

So what's the compromise?

Step 1: - The need to walk instead of climb would drive them toward converting those hands back into feet. Hands are clearly not the most ideal means of locomotion. So we should expect at least the hind legs are going to start becoming more foot-like. But the forelimbs would remain as hands.

Step 2: - The hind limbs are beginning to specialize as feet, so the animal will begin to prefer to use them to stand on, relying on their forelimbs less and less (because their forelimbs are not nearly as specialized for the task of walking.)

Step 3: - As the forelimbs become less and less important to their locomotion, .... they can start moving away from that role, and focusing on their primary role of grasping. They no longer need to be dual purpose limbs.

Step 4: - As the hands become increasingly useless as feet, the animal increasingly moves toward walking upright.

That corresponds well with the findings of the paper. The two selective pressures compliment one another.

I don't think humans have the ability to swim. Throw a kitten into water and it will swim to shore. Throw a human baby in and it will drown. Or an adult who never learned how to swim.

The single human attribute that stands out most to me is technology. We are both the weakest and strongest of mammals. Weakest in that we lack sharp teeth, or claws, or ability to run fast, we are mediocre tree climbers, we are not physically strong, or particularly big, and we cannot even digest our food very well, unless it is cooked first. However, allow us our technology, and we jump to the top of the food chain. We become the strongest, fastest, most effective killers of all mammals.

All we need to do to decide why we have unique features like upright stance and hairlessness is to allow for our use of technology. If our early ancestors became dependent on simple technology, like stones for bashing, and sticks for spearing, we see that being able to stand and even run in an upright position will aid that facility and thus increase survival. An upright ape with a length of wood with a sharp end can fend off predators - especially if there is a gang of such upright apes, all stabbing together. Gathering food using tools and weapons becomes much more effective.

Hairlessness would evolve as a consequence of developing technological means of keeping warm, like fire and clothing. Once a natural coat of hair is no longer essential for body warmth, certain benefits of shedding that hair become dominant, like parasite control, and keeping cool in long running hunts. A more widespread subcutaneous fat layer evolves, since that aids keeping warm, but does not reduce the ability to cool off using sweating, or the parasite control. So the fat is a consequence of hairlessness - not aquatic lifestyle.

And so on.

Kind of impossible to prove that our ancestors did not spend a fair amount of time acquiring food from rivers, streams, lakes and oceans.
The shells of shellfish can last for millions of years, while fishbones usually degrade much faster, so analysing shellfish middens seems to be the best way of looking into the aquatic concept.
For most of the last million years, sea levels were much lower, so most of the shellfish middens would be under water now, and with higher sea levels during the last interglacial, most shellfish middens from earlier times would most likely have been washed away.
What we do have is shellfish middens from 140,000 years ago, so we know that atleast that far back, our early modern ancestors were eating shellfish, and most likely fishing during runs like the current salmon runs------even the bears know this is easy pickings. And scavanging along a river, lake , or sea shore is a tad easier than wandering the savanna in hopes of finding your next meal. After a flood, drying oxbow lakes seem almost full of stranded fish. Then look at our modern humans who cluster along shorelines. How much of what we do every day is still governed by learned instinct handed down from previous generations?

Does any of that prove that we lost our fur, went bipedal, and developed subcutaneous fat from fishing and gathering shellfish?
NO
But no other causal theory for those changes can be proven either.
So
It remains up to the individual what (s)he wishes to believe.

It raises a really interesting point, which would favor the savanna hypothesis. Think about it: You've got these apes no longer in the trees who now have to walk around on the ground. But their hands are still useful and increase locomotion is not enough of a benefit to justify losing them.

I think it puts another nail in the coffin of the savanna hypothesis, which never made any sense anyway:

1) Plenty of four-legged ground animals have useful hands - raccoons, baboons, chimps, gorillas, etc.
2) The major early stages of bipedalism apparently were passed while there were lots of trees around, before the savanna.
3) The hands are not abnormally useful, in any but chimp and monkey and raccoon sense, until after bipedalism.
4) the notion that the pressure of walking on the ground favors bipedal stance seem very peculiar. The early stages of bipedal structural adaptation are a severe handicap.

Step 1: - The need to walk instead of climb would drive them toward converting those hands back into feet. Hands are clearly not the most ideal means of locomotion. So we should expect at least the hind legs are going to start becoming more foot-like. But the forelimbs would remain as hands.

That would be need, and practice, of walking on four feet. The gorilla is the easiest example - notice that its hind hands are not converting into feet.

Steps 2 through 4 conflict with Darwinian evolution (the direction of influence is backwards).

Required is not a "need to walk" but a need to walk on the hind legs only, for significant and extended lengths of time, despite not having adapted limbs or feet or pelvic girdle or inner ear, etc.

Iceaura

None of that is a problem if you assume technology came first. Once our pre-human forebears were committed to basic technology for survival, the evolutionary adaptations would have come thick and fast, to make us better at using technology. merely having effective hands is not enough. There must be that commitment to the basic technology.

Upright stance from needing to able to use fore limbs for wielding and carrying tools and weapons.

The savannah move was probably a consequence of technology use, and social cooperation. Once the upright ape could wield sharp lengths of wood as spears, or other objects as clubs, then as a group they could fend off predators. This would permit them to venture out into the savannah to scavenge, such as eating dead animals. With those weapons, and working together, they could even drive predators off the kill.

Supervixen, I think the attraction of the Aquatic Ape hypothesis is that it appears to tie a lot of the traits that make homo sapiens different from other apes to a single environmental factor. So much explained so simply. However, examined closely and individually, I don't think traits like bipedalism and thinned body hair are clearly or obviously adaptations to life in water at all. As you say, everything can also be explained in other ways. There's sufficient general interest about human evolution that it crosses over from an academic pursuit of knowledge into infotainment. Much of what is written has the interested public in mind and academic standards get blurred.

I'm not sure how the questions of how they arose to become variants within a proto-human population and what selective circumstances took those without them out of the equation can be answered definitively. Maybe we'll get more answers from studying human genetics but in the absence of clear physical evidence this whole field of inquiry looks limited to speculation and hypothesis. Calling any of them a theory is a stretch. Hopefully they are bounded by knowledge of a higher grade than speculation. I'm not sure that Morgan keeps within those boundaries. But, I have issues with other more respected and well regarded voices in evolutionary anthropology - because of the less than adequate job they've done of looking at that most crucial and solid baseline - the way we are now.

Many of the arguments have been aired here before -many of the commenter's familiar with each others views. I've had an ongoing amatuer interest in the evolution of "hairlessness" - that was the first debate I got involved in here at Science Forum, initially to contest the idea that human body hair is effectively functionless. It remains highly functional - as part of our sense of touch - but it doesn't speak well of this field of inquiry that this sensory function has been so consistently ignored and overlooked. Morgan overlooks it, but so do most leading academics engaged in inquiry about the evolution of our furlessness.

If the functions of the traits we have now aren't correctly recognised, speculation about how they arose will, IMO, almost certainly be flawed.

Originally Posted by Ken Fabos

contest the idea that human body hair is effectively functionless. It remains highly functional - as part of our sense of touch - but it doesn't speak well of this field of inquiry that this sensory function has been so consistently ignored and overlooked. Morgan overlooks it, but so do most leading academics engaged in inquiry about the evolution of our furlessness.

What? You use your hair for touching? I tend to use my fingertips. No hair there.

Personally I link furlessness with bipedalism and the capacity to sweat freely as a method of maintaining temperature.

This, of course, links to the concept of persistence hunting. Which makes it either a neat, parsimonious, comprehensive explanation for a lot of features that make us distinct from all other mammals, not just primates, or yet another in the long line of humans seeing patterns where there are none.

I lean towards it because it "helps" explain how weak, feeble, vulnerable humans could hunt large intimidating animals. The idea that all we had to do was chase just barely fast enough to stop them from cooling by panting while we merely worked up a healthy sweat - and keep it up for just barely long enough to reduce them to quivering, immobile exhaustion while we, just a bit puffed and footsore, run up and deliver the coup de grace.

Which, Adelady, is of course, a big part of the story. Not the whole story, of course.

Ken has a point when he talks of hair as a sensory organ. Minimal hair gives a very good addition to our sensory spectrum. True. Also not the whole story.

Others talk of parasite control. Also true, but not the whole story.

I ask another, perhaps more difficult question. If reducing hair cover confers those benefits, why is Homo sapiens the only terrestrial mammal in our size range to go functionally hairless? Why are we unique?

I answer with technology. The advantages as stated above are real. But losing the thermal insulation of hair is such a drastic step that no other terrestrial mammal in our size range has ever done it. The only reasons humans can evolve functional hairlessness and accept the above advantages is that we have other means of keeping warm through technology - fire and clothing.

The only reasons humans can evolve functional hairlessness and accept the above advantages is that we have other means of keeping warm through technology - fire and clothing.

I'm not sure it's the one and only reason - but it certainly looks like a good trade-off. The physical capacity to hunt large animals is linked to a loss of the individual warmth maintenance provided by fur. Happily those same large animals provide large skins to convert into shelters for groups - tent style roofs or protection for cave entrances - and cloaks or similar coverings for individuals.

Originally Posted by adelady

The idea that all we had to do was chase just barely fast enough to stop them from cooling by panting while we merely worked up a healthy sweat - and keep it up for just barely long enough to reduce them to quivering, immobile exhaustion while we, just a bit puffed and footsore, run up and deliver the coup de grace.

Unfortunately, the archaeological evidence doesn't offer any support to this hypothesis. (except, maybe in Australia)

The earliest clovis, then folsom finds in america indicate that paleo hunters used their brains more than their leg muscles. They either lured the herbivores into valleys by selectively burning the grasses to encourage new growth, then ambushed the quary, or stampeeded them over cliffs, then delivered the coup de grace.
Most kill sites found (so far) had bones from many animals, and a few spear points. Pre horse amerindians covered themselves in the hyde of the animal they were hunting(bison), and slowly crawled up on the herds until close enough to shoot them with bows and arrows.
Looking at the cave paintings, it seems that a large focus was on hunting animals when they were crossing rivers, or when lordosing(in the rut),when their minds were more on sex than survival.
Before, the invention of bows and arrows, spears were the best means of killing game. and for the large animals, being up front and personal wasn't a very wise thing to do unless you had an edge, and the first edge seems to have been the atlatl, which brings us to Australia, where the aboriginal hunters could bring down fleeing animals at a dead run. Evidence for atlatls goes back perhaps to 35-40 thousand years, as does that for fish hooks and barbed harpoon points. It would seem that the invention of the bow and arrow happened after the Australian inmigration and before the later(10-11kybp)inmigration to the americas---(to the best of my knowledge, no arrowheads have been found in pure clovice sites, which seem most probably from european stone cultures), And likely became more valuable with the demise of the megafauna.
I can not imagine how having subcutaneous fat would be of benefit for running after prey animals. And, i ain't nearly fast enough to catch even slow moving prey unless i have wounded it first.

Which came first, saving accidental fire or making fire? Then if you once have fire, how to carry it from place to place, camp to camp. bipedalism and free hands would surely be a great boon to survival.

(wild guess du jour)
We have always been an eclectic species when it came to feeding ourselves. Omnivores forever using damned near anything that "came to hand", carrying fire "in a hollow fennel stalk", setting snares, throwing sharpened rocks(imagine a discus made by sharpening a suitable rock hurtling into the side of a prey animal, then follow the blood trail to lunch), catching fish in shallow streams and gathering shellfish, swimming, rafting, and building boats, etc...

Originally Posted by iceaura

2) The major early stages of bipedalism apparently were passed while there were lots of trees around, before the savanna.

We've hashed this out before with both geological evidence or the rift valley formation and paleo climatology and it's simply not true. We also see primates living in that transition areas between heavy forest and savanna such as baboons which use both quad and bi running.

4) the notion that the pressure of walking on the ground favors bipedal stance seem very peculiar. The early stages of bipedal structural adaptation are a severe handicap.

Care to support that?
Some studies such as this one, suggest quite the opposite that even early bipedal forms are both more efficient efficient, which we know is a common and significant selective mechanism but without significant handicaps (some speed reduction)
"The predictions conflict with suggestions that A. afarensis used a ‘shuffling’ gait, indicating rather that the species was a fully competent biped. "
Chimpanzee locomotor energetics and the origin of human bipedalism

Or this one:
" Analyses of these features in early fossil hominins, coupled with analyses of bipedal walking in chimpanzees, indicate that bipedalism in early, ape-like hominins could indeed have been less costly than quadrupedal knucklewalking. "


Stride lengths, speed and energy costs in walking of Australopithecus afarensis: using evolutionary robotics to predict locomotion of early human ancestors

Or this studies of monkeys trained to walk upright which found few disadvantages for efficiency and conclude:
"t, the finding that training considerably improved bipedal walking a posteriori may explain why the very first bipeds that might not yet have been morphologically adapted to bipedal walking continued to walk bipedally. The evolutionary transition from quadrupedalism to bipedalism might not be as difficult as has been envisioned..."

ScienceDirect.com - Journal of Human Evolution - Do highly trained monkeys walk like humans? A kinematic study of bipedal locomotion in bipedally trained Japanese macaques

The point being that there's plenty of support that suggest that transition to bipedel wasn't as severely handicapping as you assert and held energy advantages-- advantages that probably supported other developments as well, such as increased brain size etc.

To sculptor

Re stamina hunting.

This is not uncommon and is found in several tribes in Africa, even to the present day. The San, for example, have been documented by video record using this system. It generally involves a young and very fit male as primary hunter. He runs at his target animal, which sprints off. The young hunter uses his highly developed tracking skills (his brain) to follow at a crackingly fast pace. Each time the young hunter spooks his prey into sprinting off, it gets more and more exhausted, till the young hunter can run right up to it and stab it.

At this stage, the other hunters will catch up and help to return the catch to the tribe, and fend off any predator trying to steal the catch. This has been video recorded, and is hardly apocryphal.

Homo sapiens has been around for 200,000 years, and atlatls and bow and arrow for a mere few tens of thousands, even in Australia. Stamina hunting has almost certainly been in use for a long, long time.

Harold, unless yours don't work properly you've lived your whole life immersed in the sensations that hairs provide - the brush of cloth, the puff of breeze, the buzz of insects. Just brush the hairs on an arm or leg and you can confirm that they extend your sense of touch beyond the surface of your skin. When you have goosebumps that distance is extended; coincidence that, during fright and emotional arousal that sensitivity is extended to it's maximum?

The mechano-sensory function of hairs is ubiquitous, yet surprisingly, many people don't differentiate between touch sensation that arises from hairs being moved and vibrated and that from direct skin contact. Of those who don't appear to have noticed some are academics who really have no excuse - leading evolutionary anthropologists who have engaged in scientific enquiry into how our reduced furriness arose. Nina Jablonski, in SciAm lists the diverse functions of hair in mammals from the obvious insulation to camouflage and the emotive signalling of raised hackles but this function that is (as far as I can determine) universal across all mammals and probably predates hairs as insulation, was left out.

This omission is not a minor one; hairs-as-sensory-receptors has direct relevance to one of the competing hypotheses for evolutionary advantages of reduced furriness - reduced susceptibility to ectoparasites. Not good academic practice to leave out something that tends to support a competing hypothesis - good science requires it get mentioned along with sound reasoning for why it won't affect your conclusions. What lets Jablonski, Wheeler and others off the academic malpractice hook is that the proponents of the ectoparasite hypothesis just as consistently failed to take account of this sensory function.

Back when "The Evolution of Human Hairlessness" was a live topic here I suggested an increased sensitivity to small stimuli was a consequence of sparser, shorter, finer body hair and that this helps alert us to the presence of potentially disease carrying parasites. I couldn't find any supporting peer reviewed papers although I've personally avoided being bitten by the Australian Paralysis Tick - something truly worth avoiding if possible - because I felt them as they disturbed the hairs on my legs on their way to a suitable location to dig in. After having felt them they were also easy to locate and remove because the hairs were sparse and fine.

Since then a paper by Isabelle Dean and Mike Siva-Jothy in Biology Letters - "Human fine body hair enhances ectoparasite detection" - has been published that provides experimental evidence that androgenic body hairs help detect the presence of ectoparasites.

Actually I tend to the view that the ectoparasite and hot weather endurance hypotheses aren't mutually exclusive - indulging in speculation of my own, perhaps the reduced parasite loads (and reduced incidence of infectious disease) was sufficient to see a marginal furless variant that was otherwise disadvantaged in cold conditions firmly establish itself in the population mix. Maybe they were a variant that found it useful, even essential, to build better shelters, line them with hides, drape furs around vulnerable infants and children and otherwise adapt behaviorally to compensate. Just to be difficult and contrary, rather than a period of extreme heat, let's imagine an unexpected extreme cold period- those who saw little need or point to wasted efforts on shelters or keeping hides to drape around themselves - they've got fur! - failed to cope with so well as the technology reliant baldies. Later the endurance advantage in hot conditions may have become apparent, enhanced via gene flow when mated with another variant, one that had more abundant and watery sweat.

(Not insisting on such a scenario, but my point is that the dominance of an apparently disadvantageous change - reduced thermal insulation - can initially arise out of circumstances that had nothing directly to do with improved hot weather endurance, yet ultimately that's what resulted. Not a single factor, but a continuing succession of survival challenges that can see a physical advantage become at times a disadvantage and vise versa).

Originally Posted by lynx

We've hashed this out before with both geological evidence or the rift valley formation and paleo climatology and it's simply not true.

What "we" noted was that it was true. You appear to have forgotten. The early bipedal primates lived in wooded areas.

Originally Posted by lynx

We also see primates living in that transition areas between heavy forest and savanna such as baboons which use both quad and bi running.

No primates except hominids run around on two legs. Baboons will spend a little bit of time once in while on their hind legs, as will horses and raccoons and squirrels, but when they need to run they get down on all fours, for speed and efficiency and agility and all the other advantages of the morphologically adapted gait. They do not "use bi running". They are too well adapted to savanna life for that.

Originally Posted by Lynx

Care to support that?

That quadrupeds have trouble walking on their hind legs, are awkward and clumsy at it compared with their regular gait? I'll let you claim otherwise first, in public. Then I will refer you to the macaque study you linked below, where the researchers went to a great deal of trouble to study what they and everyone else have long recognized to be an issue: how do you get a quadruped to spend enough time on its hind legs, where it is clumsy and slow, to create evolutionary advantage for radical enabling structural modifications?

Originally Posted by lynx

Some studies such as this one, suggest quite the opposite that even early bipedal forms are both more efficient efficient, which we know is a common and significant selective mechanism but without significant handicaps (some speed reduction)

Those, and the rest of your examples, are early hominids, fully bipedal, not transitional forms. They are completely irrelevant to this discussion, except as they provide yet more evidence that the bipedalism was one the first, if not the first, human feature to have evolved - predating the big brain, with its great tool and language and fire control and sophisticated hunting and so forth, in particular.

And predating the savanna transition.

Originally Posted by lynx

The point being that there's plenty of support that suggest that transition to bipedel wasn't as severely handicapping as you assert and held energy advantages-

? Oh man.

Look, just because you can train a monkey to walk better on its hind legs than it could without training, does not mean that it walks better on two legs than it does on three or four. The energy advantages were over its untrained bipedal gait - similar advantages are gained by humans who practice walking on their hands. It gets easier, more efficient.

And the fact that the improvement in hind leg walking required such training, was not a simple consequence of occasional upright locomotion, establishes the central matter: something stood the ancestors of hominids up on their hind legs and kept them there, under some kind of pressure or advantage, hours a day for many thousands of years. They had to be "trained", these early primate quadrupeds, for many, many generations.

Originally Posted by skeptic

None of that is a problem if you assume technology came first. Once our pre-human forebears were committed to basic technology for survival, the evolutionary adaptations would have come thick and fast

Right you are. In particular, the most influential item of technology we could assume would be the handbag, or primitive backpack. Everything else would follow thick and fast from dependence on carry bags - they would enforce upright stance so that stuff wouldn't fall out, you would be able to carry any tools you made from place to place, the mystery of the incompetent baby would be solved - they wouldn't need to hang on for themselves - , you would need big brain forethought to know what to put in it and keep it organized, and so forth. Once they were committed to carrying handbags around, the stage was set for the primates to evolve into humans. I think that's my favorite so far.

Animals other than human that used bipedal locomotion.

Velociraptor.
Tyrannosaurus.
Frilled lizard.
Kangaroo
Wallaby
Ostrich
Emu


and many, many more. Noticeably, they are/were all very efficient and fast movers.

Not that I believe human efficient running came directly from upright stance and bipedal motion. The original change to upright stance and bipedal locomotion was to carry and use tools and weapons, and later evolution equipped our ancestors for efficient endurance running. I will ignore the sarcastic comments about hand bags.

it's got a strap i call it a shoulder bag

Originally Posted by skeptic

The original change to upright stance and bipedal locomotion was to carry and use tools and weapons,

Bullshit. No evidence in favor, no Darwinian sense to it, and doesn't fit the known structoral sequence. You haven't considered the sophistication necessary behind the development of tools and weapons that can, or would, be carried around at the expense of bipedal locomotion. The first bipedal walkers were quadrupeds with brains a bit smaller than a modern chimp's, walking on their hind legs. They were not traveling cross country dependent on a kit of tools they could not, at the time, easily create, employ, or transport.

Of course, there is a way to make sense of the early tool carry notion: if they were amphibious, foraging in shallow water, there would have been great advantage to carrying the simplest of tools from shore (pry sticks, shell-breaking rocks) and booty back to the beach (feed the kids, cache, etc). More significant, unlike on land there would have been very little penalty for bipedal walking - the water takes the weight and balance, imposes breathing problems better handled by upright stance, and penalizes quadrupedal locomotion efficiency even more than bipedal. So more gain, less (relative) pain, advantages to simple tools and enabling of their consistent use leading to dependence.

Originally Posted by skeptic

and later evolution equipped our ancestors for efficient endurance running. I will ignore the sarcastic comments about hand bags.

You ignore things like that at your peril - it's quite probable, very much indicated by the evidence and sober consideration, that carry bags and slings were among the very first technologies developed by humans. They certainly predated weapons, probably controlled fire (it has to be carried, in the early stages), possibly even shaped hammerstones (rocks are really inconvenient to carry around).

It's possible the baby sling was invented before the modern, heavy, helpless baby appeared on the scene.

Originally Posted by iceaura

You haven't considered the sophistication necessary behind the development of tools and weapons that can, or would, be carried around at the expense of bipedal locomotion. The first bipedal walkers were quadrupeds with brains a bit smaller than a modern chimp's, walking on their hind legs.

The first tools would have been objects found lying around. A pre-human could pick up a rock to use as a tool, say to break open rotten wood to extract juicy grubs, and accidentally find a rock that is specially good for the job. Normally such a tool would be discarded after use, but our exceptional ape decides to hang onto it. That is the kind of thing that would be the beginning of the technological ape.

On brain size and tool use - it appears not.
Homo floresiensis had a brain little bigger than that of a chimp, yet made relatively sophisticated tools from knapping stone. If our first technological ape had a brain a little smaller than a chimp, that would not prevent it using tools. After all, the New Caledonian crow not only uses tools, but makes them, and it has a brain half the size of your thumb.
http://www.youtube.com/watch?v=TtmLVP0HvDg

btw:

Animals other than human that used bipedal locomotion.

Velociraptor.
Tyrannosaurus.
Frilled lizard.
Kangaroo
Wallaby
Ostrich
Emu

The kangaroo and wallaby are in one evolutionary line, and do not walk much on their hind legs. I can't find out whether the lizard actually walks around on its hind legs ever (rather than running in escape or threat mode, efficiency sacrificed). The rest are all members of one other evolutionary line, which quite possibly developed its original bipedal structure as an adaptation to wade foraging in shallow water.

Just saying. Not sure what the relevance was supposed to be, of that list.

Originally Posted by skeptic

Normally such a tool would be discarded after use, but our exceptional ape decides to hang onto it.

Not if it has to walk on its hind legs to carry it. Too much penalty - chimps don't carry rocks around for days at a time, in case they run into the same kind of log again. They don't even carry termite sticks they've made at some trouble. They need their front hands for climbing, walking, etc.

And one ape won't do. One rock won't do. The entire situation is involved.

The advantages of carrying have to outweigh the disadvantages essentially permanently, cross country, all year long, for thousands of years, among almost all the apes of the breeding group. If the carrying involves bipedal walking by quadruped apes, those advantages would have to be dramatic, huge, to be a net benefit.

Originally Posted by skeptic

Homo floresiensis had a brain little bigger than that of a chimp, yet made relatively sophisticated tools from knapping stone.

It was a biped, and its brain was proportionately bigger - not much, but enough to measure - than a chimp's, and it seems to have been a miniaturization of a larger tool capable hominid - that's a much different set of evolutionary pressures.

Originally Posted by iceaura

The rest are all members of one other evolutionary line, which quite possibly developed its original bipedal structure as an adaptation to wade foraging in shallow water.

Citation of this assertion please!

And btw I can add members of Dryosauridae and Pachycephalosauria to that list.

Originally Posted by iceaura

The advantages of carrying have to outweigh the disadvantages essentially permanently, cross country, all year long, for thousands of years, among almost all the apes of the breeding group.

Not really.
Lots of animals carry stuff (mainly food) which they then store for later use.
Why should our tribe of early pre-humans not have learned to carry tools and store them for later use?

Originally Posted by iceaura

Not sure what the relevance was supposed to be, of that list.

Just that bipedal locomotion is thereby shown to have advantages. If it was not inherently efficient, it would not have evolved so many times. Being a quadruped is not necessarily superior in terms of fast movement. During the era of the dinosaurs, there were quadrupedal predators, which nevertheless proved less successful than the bipeds.

as/re dynosaurs:
can you name any
2 legged herbavores?
4 legged carnivores?

Herbivores:
Pachycephalosaurs, Dryosaurids, and Therizinosaurs

There are no 4 legged carnivorous dinosaurs that I know of, but there were very large 4 legged carnivores in the Crocodylians

Originally Posted by Paleoichneum

Herbivores: Pachycephalosaurs, Dryosaurids, and Therizinosaurs ...

I had thought the Pachycephalosaurs and Therizinosaurs were omnivorous.?

Postosuchus was a four legged carnivore in the late Triassic.
Postosuchus - Wikipedia, the free encyclopedia

Originally Posted by skeptic

Postosuchus was a four legged carnivore in the late Triassic.
Postosuchus - Wikipedia, the free encyclopedia

which sits in the clade Crurotarsi as a sister clade to the Crocodylomorpha, and is not on a direct lineage to the dinosaurs

Originally Posted by Sculptor

I had thought the Pachycephalosaurs and Therizinosaurs were omnivorous.?

Current opinion is that both groups were herbivores.

So, here's the tie in
carnivorous bipedalism

"we're bipedal because"
be it shellfish, fish, bunnies, snakes, birds, or big furry animals
we took the flesh eating path millions of years ago
?

Shellfish...LOL. When we know the rift valley has been become increasingly arid and more grass based over the past 10 million years.
"High
rates of dietary change later in the record (9.3–3.2 Ma) likely
occurred in conjunction with major habitat change that, in turn,
produced faunal change, including the appearance of stem
hominins in the fossil record. "
http://www.pnas.org/content/early/20...35108.full.pdf

Other paleo climate studies show the increasing variability and punctuated periods of drying in the great rift valley--we didn't evolve bipedalism in water plentiful dense forest, we evolved to walk in thinly forested patches, increased aridity, and in places where we were probably forced to leave the cover of trees to cross grasslands in our quest to find food, water etc.

"Forested conditions in the early Miocene gave way to mixed grassland and forest in the mid-Miocene. http://www.google.com/url?sa=t&rct=j...uzyroOXngmBgLA
"
Most antropology up until a couple decades ago vast oversimplified the climate change including the proponents of aquatic ape hypothesis, who in the light of current data, have a theory that ironically depends on evolving to wade and swimming in a place with less and less water.

Originally Posted by skeptic

Not sure what the relevance was supposed to be, of that list.


Just that bipedal locomotion is thereby shown to have advantages.

OK. So does quadra and sexta and octa.

Originally Posted by Paleo

The rest are all members of one other evolutionary line, which quite possibly developed its original bipedal structure as an adaptation to wade foraging in shallow water.


Citation of this assertion please!

What assertion? That there is a possibility wade foraging (predation, that would be, probably) - a very common niche of extant dino-related bipedal animals worldwide - had something to do with a line of four legged early dinos getting up on their hind legs? C'mon - are you actually going to claim there is no such possibility?

I mean, it's a minor point - we would still have hominids to explain - but geez.

Originally Posted by lynx

Other paleo climate studies show the increasing variability and punctuated periods of drying in the great rift valley--we didn't evolve bipedalism in water plentiful dense forest, we evolved to walk in thinly forested patches, increased aridity, and in places where we were probably forced to leave the cover of trees to cross grasslands in our quest to find food, water etc

That has no support in the physical evidence - the earliest form we have lacks a heel, for example, and lived in a woodland. And animals forced to cross grasslands would be severely punished for adopting slower, less efficient, more visible and vulnerable modes of locomotion. We need something that rewards hours of bipedal stance in a quadruped, not something that makes a lot of hard, slow work out of overland travel and exposes them to every predator for miles.

Primates forced from the trees unto grasslands become baboons, not slow and visible and naked and fat covered and fangless leopard lunch.

Further, you mistake the conditions under which a formerly forest dwelling tree climber would be forced or led into shallow water foraging - a thinning density of fruit and other forest provender, an increasing necessity of crossing dangerously open country to reach lucrative forest patches, and the like, are all pressures that increase the rewards of this new and unprecedented primate niche. The last of the thick trees are near the water, the pickings are rich in both directions, the simple tools are easily kept handy and very valuable (the penalty for dedicating the front hands to tool manipulation is much reduced) - it's a niche that works.

Originally Posted by iceaura

Originally Posted by Paleo

The rest are all members of one other evolutionary line, which quite possibly developed its original bipedal structure as an adaptation to wade foraging in shallow water.


Citation of this assertion please!

\What assertion? That there is a possibility wade foraging (predation, that would be, probably) - a very common niche of extant dino-related bipedal animals worldwide - had something to do with a line of four legged early dinos getting up on their hind legs? C'mon - are you actually going to claim there is no such possibility?

I mean, it's a minor point - we would still have hominids to explain - but geez.

Yes I am going to insist. you made a very specific point and I want to know if it has any backing in the peer-reviewed lit on Dinosauria. Especially in light of the counter examples I provided that show multiple lineages which developed bipedal locomotion and not the single group.

Originally Posted by iceaura

...That has no support in the physical evidence...less efficient

And your source for less efficiency is where?
And I'll insist this time.
Here's yet one more study that suggest bipedel walking is more efficient--and this study says that's true even for modern chimps.
"Bipedalism is a defining feature of the hominin lineage, but the nature and efficiency of early hominin walking remains the focus of much debate. Here, we investigate walking cost in early hominins using experimental data from humans and chimpanzees. We use gait and energetics data from humans, and from chimpanzees walking bipedally and quadrupedally, to test a new model linking locomotor anatomy and posture to walking cost. We then use this model to reconstruct locomotor cost for early, ape-like hominins and for the A.L. 288 Australopithecus afarensis specimen. Results of the model indicate that hind limb length, posture (effective mechanical advantage), and muscle fascicle length contribute nearly equally to differences in walking cost between humans and chimpanzees. Further, relatively small changes in these variables would decrease the cost of bipedalism in an early chimpanzee-like biped below that of quadrupedal apes. Estimates of walking cost in A.L. 288, over a range of hypothetical postures from crouched to fully extended, are below those of quadrupedal apes, but above those of modern humans. These results indicate that walking cost in early hominins was likely similar to or below that of their quadrupedal ape-like forebears, and that by the mid-Pliocene, hominin walking was less costly than that of other apes. This supports the hypothesis that locomotor energy economy was an important evolutionary pressure on hominin bipedalism."

ScienceDirect.com - Journal of Human Evolution - The metabolic cost of walking in humans, chimpanzees, and early hominins

Further, you mistake the conditions under which a formerly forest dwelling tree climber would be forced or led into shallow water foraging - a thinning density of fruit and other forest provender, an increasing necessity of crossing dangerously open country to reach lucrative forest patches, and the like, are all pressures that increase the rewards of this new and unprecedented primate niche. The last of the thick trees are near the water, the pickings are rich in both directions, the simple tools are easily kept handy and very valuable (the penalty for dedicating the front hands to tool manipulation is much reduced) - it's a niche that works.

And? Those fruits don't stay ripe year round. Much like most species in those sparse locations (e.g. baboons, and many herbivores), they move to find food. And like those other animals, except in an emergency, they'll be walking the vast majority of the time.

And again I'll ask....what wading?

And where's the shell middens, fishing equipment etc....in this drying place. IT's probably the most obvious flaw in the AA hypothesis, one few really know about when it came out. The lack of evidence for the aquatic food, and climate changes pretty much rule out the whole idea.

Just because the rift valley is where some of our potential ancestors were found, doe not mean that that was the only place they lived, nor the only niche they exploited.

eg: digging up my rural home would not lead to knowledge about the big cities.

(incidentally: http://www.ldeo.columbia.edu/~peter/...n_ch4.2010.pdf
nice link will help inform wayne in the liquid H2O thread---thanx)

LF's point is valid, though. Not just middens of shellfish, but also actual hominid fossils, in aquatic or marine sediments. Where are they? The aquatic ape hypothesis collapses by virtue of zero evidence.

On Iceaura's quibble. Erect stance would equip prehumans for life on the risky savannah, through allowing them to wield weapons, even if they were just tree branches with sharp points. If they also worked together (and all our predecessors appear to have been communal), then they could fend off leopards and the like.

Assuming the early technologists used just tools and weapons that came easily to hand, like wooden spears, bones, and stones, without shaping them, there would be no fossil evidence. This is not too much of a stretch since chimps in the wild use tools, with one tribe of chimps shown to use short wooden branches as stabbing spears in hunting. I merely suggest that prehumans used such technology to a much greater extent than modern chimps.

Originally Posted by Paleo

Yes I am going to insist. you made a very specific point and I want to know if it has any backing in the peer-reviewed lit on Dinosauria.

I have no idea what you are all excited about, and I doubt you do either. Nothing in my post there would have any reason to be backed in any peer reviewed literature, nor would it make any difference if it did or didn't. How would one even search for such a thing?

Originally Posted by skeptic

On Iceaura's quibble. Erect stance would equip prehumans for life on the risky savannah, through allowing them to wield weapons, even if they were just tree branches with sharp points.

The topic is how hominids came to have that erect stance, one eventually so refined in its structure that it would be capable of providing controlled leverage to weapons etc. That's the puzzle. The advantages of such capable bipedalism require capable bipedalism.

Originally Posted by lynx

And your source for less efficiency is where?
And I'll insist this time.

Well thank you for saving me the work of handling your latest troll - I'll use yours:

Originally Posted by lynx

Here's yet one more study that suggest bipedel walking is more efficient--and this study says that's true even for modern chimps.

No, it doesn't. Will you please read at least your own links? It suggests that the changes necessary to make chimp bipedalism more efficient than chimp quadrupedalism are smaller than many had assumed. But changes there must be, and significant ones, as described in your source - chimps are now, as your study assumes, significantly less efficient on two legs. The handicaps and penalties preventing the transition are severe.

And that is merely efficiency, one factor. Locomotion is not based on efficiency alone, or we would have no hummingbirds, no jesus lizards, no falcons, no bees. Over hazardous grassland, a quadruped needs agility and speed and camouflage as well. There is no quadruped on this planet, primate or any other, that gets up on its hind legs to walk across hazardous open ground, because the penalties are so great and the rewards so trivial and rare.

Now if some critter already well launched toward bipedalism - over the efficiency hump, say, and with a few thousand generations of refinements for speed or maybe even weaponry transport - is faced with some grassland? That's a different story. And a different topic for a thread.

Originally Posted by iceaura

The topic is how hominids came to have that erect stance, one eventually so refined in its structure that it would be capable of providing controlled leverage to weapons etc. That's the puzzle.

No puzzle.
I admit my explanation is just my hypothesis, and I do not have a method right now of testing it, but it provides an alternative explanation that, IMHO, is much more likely than the discredited aquatic ape hypothesis.

Initial steps simply consist of holding tools or weapons, and being reluctant to let them go. No real tool making. Just picking up stones or pieces of branch or bone that happen to be useful in their shape. Then not wanting to release something that is good for a purpose. If a whole tribe of apes learns this behaviour, then those that become better at upright stance and/or bipedal locomotion would be able to hang onto favoured tools, and thus gain a selective advantage in terms of survival and reproduction.

Originally Posted by iceaura

Originally Posted by Paleo

Yes I am going to insist. you made a very specific point and I want to know if it has any backing in the peer-reviewed lit on Dinosauria.

I have no idea what you are all excited about, and I doubt you do either. Nothing in my post there would have any reason to be backed in any peer reviewed literature, nor would it make any difference if it did or didn't. How would one even search for such a thing?

Ok, so you admit you just threw out:

which quite possibly developed its original bipedal structure as an adaptation to wade foraging in shallow water.

With no intention at all of supporting it? Were you just using it as a means to try to support the AAH by making it sound like bipedal dinosaurs were all one closely related evolutionary progression that also passed through an early aquatic phase?

Skeptic, I think the whole question may remain forever in the realms of speculation, but I tend to agree with you, that behavioral adaptation - tools, shelter, clothing but also social behaviors - are the big hominid advantage that can overcome physical limitations. When they came into play is a question but it appears to go back a very long way, most known members of that branch of apes being tool users. Teasing out whether the cooperative behaviors or improved tools was the greater factor looks pointless; they look to have developed concurrently.

Along the way these behavioral changes shift from a means to overcome limitations and disadvantage - to survive in times of changing climate and changing ecosystems or at the edges of the more ideal territories where their kind is well established - into a clear advantage that opens the possibility of dominating in those 'better' territories as well as surviving and thriving in different ones. Ultimately these behavioral adaptations become a necessity; deprived of them, those hominids who's physical evolution has been altered by long engagement with them would go cold and hungry. The doco Adelady referred to - Dr Alice Roberts The Origins of Us - talks about physical differences in bone structure of the hands of later vs earlier hominids that indicate a long engagement with tools; without them instead of getting dinner they would become dinner.

I don't see that the transition to bipedalism needed to involve any kind of crippling disadvantage; apes are halfway to bipedal already, part of the tree dwelling evolution that may have been more about the advantage of being able to stretch up and reach higher. They weren't ever likely to evolve to be faster, better equipped in the tooth and claw department or better armored and in that sense they were always going to be at a physical disadvantage; so they can't outrun a big cat or hyena. Or outswim a crocodile or hippopotamus. But working together they can protect themselves against predation and ultimately the most feared predators are readily driven off or hunted.

Originally Posted by paleo

Ok, so you admit you just threw out:
which quite possibly developed its original bipedal structure as an adaptation to wade foraging in shallow water.


With no intention at all of supporting it?

What's wrong with the obvious support immediately visible and noted?

Originally Posted by ken

Skeptic, I think the whole question may remain forever in the realms of speculation, but I tend to agree with you, that behavioral adaptation - tools, shelter, clothing but also social behaviors - are the big hominid advantage that can overcome physical limitations.

If that was what he was saying, everyone would agree with him.

Originally Posted by ken

I don't see that the transition to bipedalism needed to involve any kind of crippling disadvantage; apes are halfway to bipedal already, - -

The disadvantages facing a quadruped, such as a chimp or any other primate except one, walking on its hind legs/hands, are not visible to you?

Originally Posted by ken

The doco Adelady referred to - Dr Alice Roberts The Origins of Us - talks about physical differences in bone structure of the hands of later vs earlier hominids that indicate a long engagement with tools; without them instead of getting dinner they would become dinner.

So the early hominids - fully bipedal as they were - were still a long way from having hands adapted to using tools. That is very strong evidence against the notion that tool use drove a lineage of quadrupedal apes to bipedal locomotion despite its physical difficulty and disadvantage. That is evidence that bipedal locomotion came first, as common reasoning and Darwinian principle would suggest anyway, and adaptation to tools came second.

Originally Posted by skeptic

Initial steps simply consist of holding tools or weapons, and being reluctant to let them go.

Which would lead to the initial disadvantage of trying to carry something around you have no immediate use for and no proper physiology for using anyway, and suffering the consequences.

That is, unless you are proposing an environment in which hanging on to a found rock or stick had no serious penalties, and wasn't all that much of a handicap to a quadruped, and offered advantages not trumped by the cost of hind leg shuffling and poor leverage and so forth. What environment would that be? Not predator infested grassland, of course. Not a forest demanding tree climbing.

Ideally, you would propose an environment in which it was about as easy and perhaps even advantageous to walk on one's hind legs rather than on all four (minimum penalty) and one in which carrying a stick was the only way to ensure you had one handy when you needed one (maximum benefit), and so forth.

btw: what are you proposing was selected there - a genetic propensity to hang onto found rocks?

Originally Posted by iceaura

Which would lead to the initial disadvantage of trying to carry something around you have no immediate use for and no proper physiology for using anyway, and suffering the consequences.

I said "reluctant" to let go of. Even today, humans will drop something they are carrying if they are in danger, in order to scarper. If a favoured rock or sharp piece of wood is dropped, the ape could return later to pick it up. I am sure you can see the advantage of keeping a tool that is well suited to the jobs required - like digging out grubs - rather than hoping to find another bit of rock well suited. If a particular rock is found that is particularly good for the task, then it makes sense to keep hold of it.

Evolution has to start somewhere, and it is normally in small steps. My suggestion is that the first small step is to wander round carrying a favoured tool. This would require modified posture and modified gait, which evolution could work on.

Originally Posted by iceaura

Originally Posted by paleo

Ok, so you admit you just threw out:
which quite possibly developed its original bipedal structure as an adaptation to wade foraging in shallow water.


With no intention at all of supporting it?

What's wrong with the obvious support immediately visible and noted?

What exact supporting data?

Originally Posted by paleo

What exact supporting data?

Data?

Originally Posted by skeptic

I said "reluctant" to let go of. Even today, humans will drop something they are carrying if they are in danger, in order to scarper. If a favoured rock or sharp piece of wood is dropped, the ape could return later to pick it up. I am sure you can see the advantage of keeping a tool that is well suited to the jobs required - like digging out grubs - rather than hoping to find another bit of rock well suited. If a particular rock is found that is particularly good for the task, then it makes sense to keep hold of it.

Sure. But it makes no sense to carry it around while walking on one's hind legs. And you still need a selection pressure on the genetics.

Originally Posted by skeptic

My suggestion is that the first small step is to wander round carrying a favoured tool. This would require modified posture and modified gait,

Three legged, yep. Evolution would of course work against walking on one's hind legs, in this circumstance - unless something about the environment improved the cost/benefit ratio. It would be expensive and unlikely enough the easier and more efficient three legged way.

btw: The newspaper this week reports that a fossil skull of what seems probably yet another early hominid has been discovered, one that matches an earlier ambiguous fragmentary find, and we have another bipedal branch of the stem - they mention that they aren't sure whether this made or even used tools. Several of the early bipeds appear to have made their way without any obvious sign of tool use beyond chimp level.

The problem with the fossil record and tool use is that, until stone tools are knapped, there will be no fossil evidence. If Ardipithecus, for example, was in the habit of carrying stone and wooden tools, there would be no fossil evidence, since Homo habilis appears to be the first to actually carry out knapping.

Iceaura - I don't think there's a big difference, advantage-wise between apes on two legs or four when on the ground; neither is well equipped to outrun big ground based predators or run down ground based prey on the basis of superior body shape and locomotion. Similarly, I don't see a significant difference in water - which is probably a more dangerous and difficult step to make than stepping onto the savannah. The advantage comes from things other than speed and agility in water or on the ground. Tool use makes sense as a plausible 'something else'. I think the water environment is something that hominids that are already capable of working together to fend off large predators can make use of but prior to having that advantage I think it's an environment the ape-hominid would find especially difficult. And I think that the physical changes that show signs of being suited to use of tools is a consequence of long reliance on tools, not a prerequisite for tool use.

Religious people are already furious at us for saying we are apes. No you want us to tell them we are fish monkeys? I love it!

Just a little factual addition on the business of tools.

The oldest stone tools were found at Afar, Ethiopia dated at up to 2.6 million years ago. Also bones of game animals found associated, with marks from the stone tools.
World's Oldest Stone Tools

However, a recent discovery is of bones 3.4 million years old that show marks such as delivered by stone tools. No such tool of that age has been discovered, but it appears probable that they existed.
Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia : Nature : Nature Publishing Group

It would appear that tools are of great antiquity.

Originally Posted by iceaura

Originally Posted by paleo

What exact supporting data?

Data?

yes, the data that supports your Dinosauria evolution claims that you are making.

Originally Posted by pyoko

I don't think humans have the ability to swim. Throw a kitten into water and it will swim to shore. Throw a human baby in and it will drown. Or an adult who never learned how to swim.

Give birth to a human baby in water and it will swim happily as it has it's umbilical cord.

Originally Posted by paleo

yes, the data that supports your Dinosauria evolution claims that you are making.

There is no such thing as "data" that would support (or contradict, in our current state of knowledge) any claims I am making on that topic. They aren't claims of that kind.

Originally Posted by ken

Iceaura - I don't think there's a big difference, advantage-wise between apes on two legs or four when on the ground;

The apes do.

Originally Posted by ken

neither is well equipped to outrun big ground based predators or run down ground based prey on the basis of superior body shape and locomotion.

Apes don't run down prey. The animals that do are all - with one exception - quadrupeds. And that one exception uses endurance, not speed.

Originally Posted by ken

Similarly, I don't see a significant difference in water - which is probably a more dangerous and difficult step to make than stepping onto the savannah.

Well, pretty much everybody else does - including the various apes that spend much more time on their hind legs when wading.

The early stages of bipedal wading are reasonably safe and comparatively (compared with quadrupedal) much easier than hind leg walking without water support (not easier, comparatively easier, the penalty is much less) - and with some persistence and intelligence, very rewarding for a forager (quad or bi) with hands.

Note that it's not the simple existence of hazard or difficulty that decides the matter, but the relative benefits, the cost/benefit relationship.

It would appear that tools are of great antiquity.

Unlike grassland hind leg "walking", wade foraging provides both selection pressure in favor of freeing the hands for tool carrying, and reduction of selection pressure against the awkward and otherwise markedly less capable and less efficient mode of locomotion.

Originally Posted by iceaura

Originally Posted by paleo

yes, the data that supports your Dinosauria evolution claims that you are making.

There is no such thing as "data" that would support (or contradict, in our current state of knowledge) any claims I am making on that topic. They aren't claims of that kind.

Then why did you make the statement re:water in the first place?

Originally Posted by paleo

Then why did you make the statement re:water in the first place?

I'm not feeding this any more. Go back and read the post.

Originally Posted by ken

I think the water environment is something that hominids that are already capable of working together to fend off large predators can make use of but prior to having that advantage I think it's an environment the ape-hominid would find especially difficult

This overlooked as interesting.

From what we can see now, it's the other way around: it's on open grassland where carrying weapons and cooperative assault works to fend off otherwise lethal predators - and at night without trees, fire either carried or kindled. These are so critical to even modern humans that it's hard to envision an early hominid spending much time in open grassland without them - they would appear to be prerequisites, for such a slow and poorly weaponized somatotype. A wade forager must simply avoid ambush while foraging in a limited and pre-surveyed area - something an early transitional biped-to-be can do at least as well as any other morphology, and probably better than a quadruped (better height for observation, with no concomitant visibility handicap as grassland imposes). So a pre-weapon, pre-fire quadrupedal ape wade foraging finds another selection pressure getting it up on its hind legs for extended durations, rewarding that awkward stunt.

Originally Posted by iceaura

Originally Posted by paleo

Then why did you make the statement re:water in the first place?

I'm not feeding this any more. Go back and read the post.

I have read it multiple times, as you are well aware. I am still waiting for explanations as to where the assertions came from and why you made them if there is absolutely no evidence for them.

Originally Posted by paleo

I have read it multiple times, as you are well aware. I am still waiting for explanations as to where the assertions came from and why you made them if there is absolutely no evidence for them.

You have received perfectly good explanations and clear reasons are obvious and visible for the post. I'm not going to play this all too common little game any more. If you're doing this on purpose, time to stop. If you can't read and follow simple posts, you'll just have to go away stupid.

Originally Posted by ken

And I think that the physical changes that show signs of being suited to use of tools is a consequence of long reliance on tools, not a prerequisite for tool use.

Exactly. So those comparatively small but significant structural, skeletal consequences of reliance on tools came long after the much more radical transformations necessary for competent bipedal locomotion. It took millions of years for advantages in tool use to affect the structure of even directly employed and critically involved and highly variable skeletal structures that could be modified without serious handicap, such as those of the wrist and hand and shoulder of an obligate biped.

That is evidence against bipedalism being a consequence of tool use.

We seem to have gotten away from the main reason the aquatic ape hypothesis does not work. That is : the simple lack of evidence.

You need to realise that the aquatic environment, whether rivers, lakes or seas, is the ideal environment for preserving evidence. Yet we have exactly zero fossil evidence for any ape making use of the aquatic environment. We have no pre-human bones in river or lake or ocean sediments. We have no midden piles of shellfish associated with pre-human remains. We have nos such evidence at all, and it is predictable that such evidence would be common if pre-humans spent any serious amount of time in the aquatic environment.

We have quite a lot of fossil evidence of pre-human remains and activity, found in forest areas, savannah areas, by the shores of old rivers or lakes, but none actually in aquatic sediments. Kinda obvious isn't it?

Originally Posted by skeptic

We seem to have gotten away from the main reason the aquatic ape hypothesis does not work. That is : the simple lack of evidence.

As noted above, with several examples, the evidence we do have supports the wading hypothesis more than any other extant hypothesis. It fits the timeline, the kinds of modifications observed, the requirements of Darwinian evolution, and the facts of known past and current human anatomy and behavior.

If the current state of evidence means that hypothesis does not "work", we are then left with no hypothesis at all. If the best supported one is not allowable in discussion, the others are surely excluded as well, eh?

I'm not quitting, either you should provide the evidence you have for multiple aquatic phases in the different Dinosauria lineages that developed bipedal postures, or you should admit that you randomly suggested it and it is bull. This is a science forum, so please put up or retract it.

Originally Posted by paleo

I'm not quitting, either you should provide the evidence you have for multiple aquatic phases in the different Dinosauria lineages that developed bipedal postures, or you should admit that you randomly suggested it and it is bull. This is a science forum, so please put up or retract it.

I'm not playing. Period. Read the post, comprehend the post, deal with the post, or don't bother.

Originally Posted by iceaura

As noted above, with several examples, the evidence we do have supports the wading hypothesis more than any other extant hypothesis.

just-so stories are not evidence

Originally Posted by marnix

As noted above, with several examples, the evidence we do have supports the wading hypothesis more than any other extant hypothesis.


just-so stories are not evidence

Exactly. And just so stories - implausible ones - are pretty much all that any other hypothesis has so far.

(There was this ape,see, and it really liked this one rock, so it decided to walk around on its hind legs for some reason - maybe to keep the rock as far from the ground as possible - and all the other apes liked the idea and started walking around on their hind legs too, or some such - hard to tell exactly what the story is supposed to be, sometimes)

I mean, when you have a school of thought that advances, seriously, the hypothesis that early pre-hominids started walking on their hind legs so they could see over tall grass; that advances, seriously, the hypothesis that early pre-hominids started walking on their hind hands so that they could use both front hands at once to carry rocks or sticks around all day every day; that advances, seriously, the claim that the usefulness and efficiency of competent bipedalism explains the adoption of hind leg walking by a quadrupedal ape; it's hard to even dignify their stories with the honorable appellation of Kipling's fine tales.

The wading hypothesis has the efficiency calculations, the cost/benefit reduction of the transitional forms, the observed behavior of apes now, the timeline and sequence of structural changes, the observed dietary requirements and habitat preferences and other behaviors of modern humans, the consistency with some other odd and unique features of human anatomy and physiology, and so forth. That isn't enough, but it's a lot better than the bag of nothing found elsewhere.

Originally Posted by iceaura

Originally Posted by paleo

I'm not quitting, either you should provide the evidence you have for multiple aquatic phases in the different Dinosauria lineages that developed bipedal postures, or you should admit that you randomly suggested it and it is bull. This is a science forum, so please put up or retract it.

I'm not playing. Period. Read the post, comprehend the post, deal with the post, or don't bother.

If your going to make shit up you need to be prepared to support it. saying read harder is NOT an acceptable excuse.

The aquatic ape theory suffers from a total lack of fossil evidence, when it should have heaps. As I pointed out, the aquatic environment is ideal for fossil formation. Savannah and forest is lousy for fossil formation. Yet where do we find the fossils? In areas characteristic of forest and savannah, and no fossils in aquatic sediments.

Sorry, Iceaura, your hypothesis does not wash.

Originally Posted by skeptic

The aquatic ape theory suffers from a total lack of fossil evidence,

All the fossil evidence we have, including the new discoveries that trashed the original "savanna" guess and forced the backtracking into "bipedal tree walking" and the like, support the wading ape hypothesis.

Originally Posted by skeptic

As I pointed out, the aquatic environment is ideal for fossil formation.

I see no reason a small, rapidly and locally evolving population of wade foraging apes would be expected to leave very many fossils in their foraging environment, any reason to think that particular location should be more easily discovered and researched than any other place, or any reason to think the many fossils of hominids discovered near or in water - including especially the earlier ones - would not count as indicative.

when it should have heaps

Reminds me - we've been a few weeks now without a creationist showing up and demanding to see all the missing fossils. They all headed back to Bible school, or what happened?

Originally Posted by paleo

If your going to make shit up you need to be prepared to support it.

And if I'm not I don't? So I don't - at least, not more than once or twice. Done playing.

Originally Posted by iceaura

I see no reason a small, rapidly and locally evolving population of wade foraging apes would be expected to leave very many fossils in their foraging environment,

You are proposing that aquatic foraging is so important to these prehumans that it redirects their evolution. That implies one hell of a lot of time spent in the aquatic environment. Lots of those apes would have died in that environment, and left fossils. But they did not.

As far as I am aware, not one single prehuman fossil has been found in aquatic sediments. Lots have been found, however, in environments that were forest or savannah.

Originally Posted by skeptic

As far as I am aware, not one single prehuman fossil has been found in aquatic sediments. Lots have been found, however, in environments that were forest or savannah.

To my knowledge, only one possible late transitional fossil has been found, and it was in probably riverbank woods.

No early transitional forms have been found. The fossil evidence we have dates from long after the bipedal transition, as we see by the diversity of the radiation. They were far from home, by the time we found them.

Originally Posted by skeptic

Lots of those apes would have died in that environment, and left fossils.

That does not follow, and

But they did not.

You don't know that.

The absence of fossils is much more striking for the upland and dryland locations, anyway: we have a lot of fossils from those environments, we have looked hard there, but no transitional ones. Clearly the transition is likely to have happened somewhere else, where we haven't looked.

Now the transitional fossil game, sort of walking half the distance with each step and complaining when we never arrive at our destination-- I'm sort of surprised to see you use this because it's usually heard from creationist. and the studies posted already show the improved efficiencies although virtually none (or actually none) are found near water, (Ow well---I know you're not a creationist).

Australopithecus anamensis is a transitional species, with studies suggesting a significant if not primary arboreal existence (not found in aquatic environments.) (e.g., http://content.karger.com/ProdukteDB/produkte.asp?typ=pdf&doi=322631, http://www.ncbi.nlm.nih.gov/pubmed/6405621

An older species is Ardipithecus ramidus, dated to 4.4 million years BCE. It has a grasping toe, showing arboreal life, and a pelvis that implies bipedal locomotion and upright stance when away from trees, but probably all four limbs in use while climbing.
Ardipithecus - Wikipedia, the free encyclopedia

Certainly not an aquatic ape, yet at least partially bipedal and upright.

Originally Posted by skeptic

Certainly not an aquatic ape,

How did you determine that? Looks very like the proposed wading ape beginnings.

Looks nothing like an adaptation to tool usage, or overland bipedal travel on the ground.

It was an arboreal ape - not an aquatic ape. But it was an ape that could walk upright.
Forest dwellers are not aquatic.

the proboscis monkey is both arboreal and a relatively good swimmer

Originally Posted by skeptic

It was an arboreal ape - not an aquatic ape. But it was an ape that could walk upright

An arboreal ape adapting to wade foraging is exactly the prediction of the wading ape hypothesis for hominid bipedalism.

This fossil, found recently, matches that long standing prediction perfectly - and, if you recall, forced drastic revision of the conventional Just So story extant at the time, re savanna travel. It also tends to contradict whatever's left of the tool carry notion - nobody is proposing that a quadrupedal ape carried tools around in the trees, used their free hands to carry babies or food while climbing, etc, as far as I know.

Originally Posted by marnixR

the proboscis monkey is both arboreal and a relatively good swimmer

Iceaura's hypothesis is an arboreal ape that wades, not swims. Swimming would not lead to upright stance. Iceaura claims that wading would. In fact untrained humans are lousy swimmers.

Add to this the fact that there is exactly zero fossil evidence to support that hypothesis, and there should be.

Another thing is that the aquatic ape hypothesis is supposed to explain why humans are functionally hairless. Genetic studies on evolution of human body lice indicates the loss of hair was relatively recent - last few hundred thousand years.
Lice DNA study shows humans first wore clothes 170,000 years ago

This would make Ardipithecus an unlikely candidate for aquatic ape, since it lived over 4 million years ago. Yet Ardi and its descendants had upright stance, showing that the gaining of functional hairlessness and that of upright stance happened at geologically different periods, and could not have a common cause.

Originally Posted by skeptic

Another thing is that the aquatic ape hypothesis is supposed to explain why humans are functionally hairless

The thread is about bipedalism. No one here is arguing for hairlessness as a consequence of wade foraging, which makes only a little more sense than hairlessness as a consequence of savanna dwelling, which makes no sense at all.

Originally Posted by skeptic

This would make Ardipithecus an unlikely candidate for aquatic ape,

That's backwards. Ardi as evidence of a wade foraging phase argues against hairlessness as a consequence of wade foraging. Ardi is still perfectly consistent with a wading ape phase, matching as it does the predictions of that hypothesis.

Interesting.

The other thread on the aquatic ape hypothesis involved a lot of claims that functional hairlessness, and the other associated but questionable feature, the subcutaneous fat layer, were consequences of an aquatic phase.

At least those are out of the way. We now have, it seems, a single claim - that a wading period led to the evolution of upright stance and bipedal locomotion. Am I correct?

Originally Posted by skeptic

Originally Posted by marnixR

the proboscis monkey is both arboreal and a relatively good swimmer

Iceaura's hypothesis is an arboreal ape that wades, not swims. Swimming would not lead to upright stance. Iceaura claims that wading would. In fact untrained humans are lousy swimmers.

i was merely commenting on the fact that being arboreal and being able to swim / wade are not necessarily mutually exclusive

Originally Posted by skeptic

At least those are out of the way. We now have, it seems, a single claim - that a wading period led to the evolution of upright stance and bipedal locomotion. Am I correct?

A review, by you, of the thread topic, is apparently in order. Get back to us when you have got yourself oriented to the discussion.

Originally Posted by skeptic

Iceaura claims that wading would. In fact untrained humans are lousy swimmers

Untrained humans are lousy walkers, runners, talkers, throwers of rocks, users of tools, finders of food, etc.

Wade foragers are often indifferent or downright bad swimmers, anyway.

Meanwhile, a six month old human baby can swim better than it can walk. Which would return you to the subject of wading, btw, if you were paying attention.

Iceaura

If you threw a 6 month old baby into a swimming pool, it would drown. Certainly it would make swimming movements, and would actually move through the water, but it could not breath and it could not remove itself from the water. Without assistance, it would drown, and quite quickly.

Humans are not natural swimmers at any age. Breathing is more important than swimming movements. Without the ability to raise our heads and breath, while in water, any swimming movements are pointless. Humans need training to swim and breath in deep water.

These swimming skills are unnatural. Even something we see as obvious, like freestyle swimming, is a recent development of more sophisticated sports learning. The first people to cross the English Channel by swimming did it breaststroke, since no one then had learned to swim freestyle. That is an illustration of how poor we are at swimming.

I consider myself to be a good swimmer. Even at age 63, in a straight swimming race, I can beat most 20 year olds. I also scuba dive. However, all my water skills are learned. I learned to swim as a child, and I learned to scuba dive at age 16. Teaching and practice made me competent in the water. Not any instinct.

Originally Posted by skeptic

If you threw a 6 month old baby into a swimming pool, it would drown.

It can't walk, either. It swims better and more easily than it walks, was the point.

Humans are not natural swimmers at any age. Breathing is more important than swimming movements. Without the ability to raise our heads and breath, while in water, any swimming movements are pointless. Humans need training to swim and breath in deep water.

All my brothers and sisters learned how to swim by trying to get out to the dock where the big kids were. Little or no training involved - nothing like the constant hand holding and encouragement and helpful balancing and so forth that got them walking, a process that took many months and much parental involvement.

Granted they were not great swimmers, before they received training - but they could make it to the dock and back easily. They could dive to the bottom and pick up stuff they found there (that was actually one of the first things learned - often before the "dog paddle").

And they had no problem staying interested, trying and trying, playing for hours on end in one fifty foot stretch of blank sand and simple water.

Originally Posted by skeptic

These swimming skills are unnatural.

Basic swimming ability comes easily, more easily than walking, to even very young humans, requiring only sufficient opportunity. No human ability is "natural", in the sense that the human does not have to learn to do it, and does not benefit greatly from cultural expertise.

Originally Posted by skeptic

Breathing is more important than swimming movements

Humans are very good at controlling their breath. Maybe the best in the animal kingdom.

Basic swimming ability comes easily, more easily than walking,

Originally Posted by iceaura

Basic swimming ability comes easily, more easily than walking, to even very young humans, requiring only sufficient opportunity. No human ability is "natural", in the sense that the human does not have to learn to do it, and does not benefit greatly from cultural expertise.




Humans are very good at controlling their breath. Maybe the best in the animal kingdom.

Basic swimming does not come easily. You only have to look around the world at different cultures. We, in the west, tend to introduce our kids to swimming. But many cultures, including those living right next to swimmable bodies of water (eg. India) rarely learn to swim. It is often pointed out that Africans do not do well in swimming Olympic events. The reason is simply that Africans, even living near rivers, lakes and the coast, rarely learn to swim.

On breath holding, to say we are one of the best is just silly. Otters, seals, dolphins, whales, manatees and dugongs are all way, way better. A true adaptation to an aquatic existence by those animals makes humans look silly.

Yet some humans swim like mermaids, so thats so pretty impressive adaption

Originally Posted by skeptic

Basic swimming does not come easily.

Yeah - it took my five year old little sister almost three days to figure it out on her own, trying to get to the dock.

It comes more easily than walking, or tool using, or throwing objects.

Originally Posted by skeptic

On breath holding, to say we are one of the best is just silly.

I didn't. What I said was relevant to the subject of swimming.

Originally Posted by skeptic

We, in the west, tend to introduce our kids to swimming. But many cultures, including those living right next to swimmable bodies of water (eg. India) rarely learn to swim.

Eskimos don't either - their water is always too cold. Dirty and dangerous water with no foraging opportunities discourages swimming - and even there children play by and in the water, rich people live on shorelines by preference, religions hold bodies of water in special reverence, etc.

There are children on Polynesian islands who can support themselves from age eight on, shallow water foraging. It's something human beings seem very well adapted to - diet, behavior, physiology.

Reverence for water is natural, since it is vital to our well being. That is not the same as having an instinct for going into the water. Widespread ability to swim is recent. Medieval Europe had very few people who would enter the water or who were able to swim. When it comes to deep water, through most of human history, fear was dominant, not attraction.

Polynesians are somewhat different in that they depend on the water for sustenance. I have spent plenty of time with Pacific island people as they walk on the reef at low tide searching for food. They enter the water frequently when the food item is in that water, but not normally over the head. Hunting in deeper water is something that has happened since European contact, with extra tools like face masks and steel spears. Since protein sources on land in many of those islands has, traditionally, been scarce, they have no choice. Even then, their main food sources are terrestrial. Mainly crops like Taro, Cassava, sweet potato, breadfruit, coconut etc.

Originally Posted by Skeptic

Polynesians are somewhat different in that they depend on the water for sustenance.

That is not "different", but quite common.

I have spent plenty of time with Pacific island people as they walk on the reef at low tide searching for food. They enter the water frequently when the food item is in that water, but not normally over the head.

It's called "wade foraging", yes. It involves diving, putting one's head under and leaving one's feet, routinely. It's capable of indefinitely (year round for years) supporting children under ten by their own efforts with little or no technology or adult help - if there is another way of obtaining food that can make that claim, I don't know what it is.

Originally Posted by skeptic

Hunting in deeper water is something that has happened since European contact,

Open ocean travel and over-the-head fishing from boats (dolphins, etc) and diving for prey is thousands of years old in many oceanside cultures including Polynesian. Dietary analysis of Easter Island, for example, dates the decline and fall of the prosperous colonizing peoples to their loss of the trees necessary for deeper water fishing boats - marked by loss of that important source of food.

The first Europeans - whaling boats etc - hired the experienced Polynesian deep water fishermen as harpooners and navigators.

...It's called "wade foraging", yes.....

I guess once we find all those bones and shells near old shorelines covered in mostly sand and corals that don't mud up the water with the slightest touch the idea might have a sliver of support. Until than, it looks completely out of whack--humans seems to evolved mostly where there's little open water, in places in a drying climate, and with water full of sediments and ash that don't support walking or sight foraging, is full of aquatic predators, and unsafe raw foods (cooking happens millions of years later).

Children of even the most inattentive parents learn to walk on schedule. Combining water, children and inattentive parents results in drowning.