Recently I visited some friends whom I hadn’t seen for a while. You’re more talkative, they said. I attribute this to flaxseed oil.
I became interested in the effects of flaxseed oil partly because of the aquatic ape hypothesis, the idea that living near water had a big effect on human evolution. During a long period of human prehistory, the theory says, we swam a lot, presumably to catch fish. If we ate lots of fish (high in omega-3) at the same time our brains grew large, it was quite possible that our brains need large amounts of omega-3 to function properly. Flaxseed oil is high in omega-3.
Elaine Morgan, the theory’s main proponent, has written several books about it, “each more po-faced [= academically correct] than the last,” she has said. I have finally read two of them and was pleased to find more scrutiny made the theory more plausible.
Background to the idea that humans were once aquatic is that several mammals have obviously become aquatic — starting on land they shifted to water. Sea lions, whales, and so on. Birds have become aquatic — for example, ducks. Insects have become aquatic. Elephants appear to have become aquatic and then terrestrial again — note how well they can swim. There is ample precedent, in other words.
Humans differ in all sorts of anatomical and physiological ways from other primates and the aquatic ape theory has straightforward explanations for many of them:
1. Humans have subcutaneous fat, other primates don’t. Other aquatic mammals do. Explanation: The fat serves as insulation.
2. Humans have almost no fur, other primates do. Other aquatic mammals don’t. Explanation: Fur creates drag in the water. In the air, fur insulates.
3. Humans are bipedal. Explanation: Walking upright keeps the head out of the water, allowing breathing.
Regarding point 2. What about fur seals?
Don’t get me wrong, I am open to the idea of the aquatic ape theory, but I don’t find theory compelling.
During a long period of human prehistory, the theory says, we swam a lot, presumably to catch fish.
This holds no water, no pun intended. Ever try spearfishing? Even with a high-powered modern speargun, powerboat and modern wetsuit, it is on a calorie expended basis, by far, the least efficient way to obtain calories. Probably negative, if you count all the times one goes spearfishing and comes back with nothing. Also, humans have to be taught how to swim and most of us, are instinctually, afraid of the water.
Humans have subcutaneous fat, other primates don’t. Other aquatic mammals do. Explanation: The fat serves as insulation.
Again, I am very skeptical about how much insulation subcutaneous actually provides. After all, we where clothes and air is much less of a conductor of heat than water is is.
2. Humans have almost no fur, other primates do. Other aquatic mammals don’t. Explanation: Fur creates drag in the water. In the air, fur insulates.
Again, other marine mammals DO have fur. Seals and sea lions certainly do, river otters do. Beavers. Not to mention the animal with the most dense fur of all animals, the sea otter. Also, marine birds certainly have feathers. Penguins, ducks, cormorants etc etc.
3. Humans are bipedal. Explanation: Walking upright keeps the head out of the water, allowing breathing.
Back to marine mammals, no marine mammals is bipedal. And the other animals that are bipedal, namely birds, such as herons, use their bipedalism essentially as terrestrial animals to stalk small game in very shallow waters. By the AA theory, based on bipedalism and tallness, a crane would be ideal for getting INTO the water and stalking game that way.
I think the theory is fun, but ultimately sort of romantic and not serious.
One more thing, I just don’t see aquatic apes spearing fish with crude spears, no flippers and no goggle like device.
Efficacy of fishing. To use your own experience as a guide here is to underestimate the effects of learning, tradition, and practice. Not to mention over-fishing.
“Humans have to be taught how to swim.” You haven’t seen pictures of swimming babies. They swim very easily.
What’s your explanation of why humans have subcutaneous fat and other primates don’t? Human subcutaneous fat increases when humans are exposed to cold.
And what’s your explanation for why humans became bipedal?
Thanks for the correction about aquatic mammals and fur. I should look at that more carefully.
Isn’t bipedalism conventionally explained by our shift from forests to open plains? The open plains of Africa gave an advantage to apes that could stand up and see above the grasses and across the plains.
Re the open-plains explanation of bipedalism. It would be nice to have one coherent explanation of the dozens of ways early humans differed from chimps rather than separate explanations for each difference. The forest-to-plains explanation doesn’t offer a good explanation for subcutaneous fat — surely the plains were hotter than the forests. And the “see over the grass” explanation is pretty arbitrary. What about looking up into the leaves? Why didn’t other primates develop bipedalism so that they can more easily look up into the trees?
As has been pointed out, not just fur seals but all seals have hair, and for that matter all aquatic and semi-aquatic mammals except whales, serenia, and hippos. All these can be explained by two factors which are well-supported: large size and thermodynamics, and in the case of the smaller whales, swimming speed. Although it’s also likely that the hairlessness of whales only evolved once and then spread to all descendants, all species we have now, rather than for each individual species.
The “swimming babies” business is an old zombie. There is an “infant swimming reflex” (just as there is an infant crawling reflex and a host of other interesting reflexes in infants). The infant swimming reflex is not unique to humans but is found in all mammals tested, including opossum, rat, kitten, rabbit, guinea pig, and rhesus monkey. They all lose this reflex within a few months after birth, and it’s likely present because the infant has just spent its life immersed in fluid up until birth.
The subcutaenous fat in humans is just like primates which are allowed to get fat. In the wild primates, like most other animals, don’t get very fat because even though fat is great for lean times, it limits mobility and makes one more vunerable to predators. In animals which have relatively little danger from predators, they get fatter than their close relatives. Humans have had, due to fire and “advanced” weapons like spears, had relatively little predator problems for hundreds of thousands of years compared to our close relatives. It’s also clear that fat has not evolved for insulation, as we can see, for instance, byt the fat deposits of whales and seals. The fat there is for shaping, to make the animal more hydrodynamic; the fat across the belly is very thinly deposited which wouldn’t make sense if it was for insultation, also in winter and cold water and poorer food supply the fat nearest the skin gets used up first which also wouldn’t make sense if it was for insulation. This according to Caroline Pond, who is certainly the foremost expert on the evolutionary significance of fat.
On the subject of hydrodynamics, fur is not a drag in the water, it aids in hydrodynamics due to breaking up the boundary layer (this has been confirmed through testing). And dolphins, for instance, have no fur but instead have evolved dermal ridges which do the same thing that a layer of fur would do. In fact, the one thing we find that’s bad for swimming speed is exactly what we have: some hair (sometimes a lot of body hair) which is often curly and decidely non-hydrodynamic.
On bipedalism, the normal paleoanthropological explanations involve looking at how and when non-human primates use bipedalism (they all do sometimes). A very tiny fraction of that is walking in deep water (usually when they do wade, they’re quadrupedal), most is during food getting and carrying, also for observation, for displays, etc. And of course some apes (orangs and gibbons) use bipedalism virtually exclusively on the ground, because they use it a lot in trees (as do other apes and monkeys of course).
In short, there are no real good reasons to think the AAT/H holds water, and plenty of really good reasons to think it doesn’t. As you can see just from these few bits of data, the only way an argument can be made for it is to ignore the real evidence and twist data into an unrecogniseable pretzel. And the idea of one cause for everything, one stop shopping (or an “umbrella hypothesis” as it’s called) is appealing to people who don’t know much about the subject but falls apart when you look at it and start learning. Even Seth’s interest in flax seed oil shows one way the theory doesn’t make sense; one of the common claims for it is that the oil he prizes (quite rightly) in flax seed and other plant and terrestrial sources is only found at the seashore — obviously that’s nonsense, yet the proponents still make the claim.
If you want to know more about the problems with the idea, you can check out my web site (the link is above). I’ve been doing this for quite a few years now and my site is used by college courses as well as by magazines and online sources, and I recently wrote the entry on the theory for the Sage Encyclopedia of Anthropology. Apologies for the long comment.
I think antrosciguy has it about covered. But to respond to Seth’s comments:
Efficacy of fishing. To use your own experience as a guide here is to underestimate the effects of learning, tradition, and practice. Not to mention over-fishing.
I couldn’t, respectfully, disagree more. My experience is based on fish behavior when being hunted. In modern spearfishing we observe all the effects of learning, tradition and practice that you mention — and yet, with all of its the very, very modern accouterments such as specialized freediving goggles, specialized freediving wetsuits, specialized freediving flippers, specialized freediving gloves, specialized freediving knives, and unbelievably powerful spearguns, spearfishing is hard. Very hard. It takes a considerable amount of courage practice, time, and skill to kill large fish regularly.
And yet, there is no way one could harvest enough fish over an extended period of time to actually subsist on or even support a family. Unless aquatic apes looked like dolphins with arms, in-water/swimming around with a crude spear is impossible.
i“Humans have to be taught how to swim.” You haven’t seen pictures of swimming babies. They swim very easily.
I have. And that is quasi-myth. They don’t actually ‘swim’. They can naturally hold their breath, but unless you bring the child to the surface, rest assured it will drown.
What’s your explanation of why humans have subcutaneous fat and other primates don’t? Human subcutaneous fat increases when humans are exposed to cold.
I suspect that other primates do — these certainly do.
And what’s your explanation for why humans became bipedal?
There are various theories on this, I don’t want to go into the pros and cons of each — however, logically, I do not have provide a competing explanation to reasonably cast doubt on AA theory.
Thanks for the correction about aquatic mammals and fur. I should look at that more carefully.
More to antrosciguy’s point — take a look at the Fastskin by Speedo:
https://www.sciam.com/article.cfm?id=the-olympians-new-clothes
One fabric, the Fastskin, works like spandex to compress the body and limit muscle oscillation. Fastskin is designed to reduce friction drag by creating ridges and valleys similar to those on a shark’s skin–the water skims over the ridges and skips the drag-inducing valleys in between them. At points where bodies curve, another spandexlike material called Flexskin–joined to the other fabric by low-profile seams–enables greater mobility. Speedo suits also feature titanium-silicon scales on the inner forearm that grip the water better on down strokes. Lastly, rubber bumps across the chest help reduce another type of resistance called pressure drag. The overall effect, Speedo asserts, is a 4 percent reduction in passive drag for men and a 3 percent reduction for women.
We cannot forget the prevalence of large marine predators as well, both in freshwater as well as salt i.e. crocodiles, alligators, hippos (while they do not technically prey on humans, they often kill them, both in the water and out), of course, various sharks, — there also no reason that a marine mammal like a killer whale wouldn’t snack on a human, even though that, for some unknown reason, is thought to be impossible.
Anthrosciguy, do you have a reference for your apparent claim that humans and other primates do not differ in amount of subcutaneous fat? I couldn’t find one at your website. Since people gain subcutaneous fat when exposed to cold, I cannot believe that fat has nothing to do with insulation, no matter what Caroline Pond says. You are plainly wrong when it comes to omega-3, the part of your comment that I know the most about. Some seafood, such as salmon, has a lot of omega-3. The aquatic ape theory doesn’t suppose it is “only” found in seafood. Of course not. Omega-3 is in every plant. It supposes that seafood is an unusually good source.
It’s not amount of fat. What the situation is is that humans can and do get fat, just as all animals do when they can get away with it. The controlling factor for most animals, including primates, is predation. Extra fat is very useful because it’s stored food, and when your food supply is off and on having that extra food is very handy; it can be the difference between life and death, or between healthy pregnancies and nursing or weak, sick young. But it limits mobility, so it makes the animal more vunerable to predators. In situations where predation is limited, an animal will become fatter than its relatives in situations where predation is not so limited. For humans, this relatively limited predation has been the case for hundreds of thousands of years, since we were able to use fire and “advanced” weapons like spears.
Now all these fat deposits are anchored to internal depots, and those of humans are just like those of other primates. When the fat of either humans or other primates gets more plentiful it spreads out and eventually is found under the skin in larger amounts, just as it is elsewhere in larger amounts. But humans can get fatter, although it’s not clear that “wild” humans actually are fatter than wild non-human primates. For instance, most primates in the wild are similar to most other terrestrial mammals at around 5% fat (it goes up at certain times of the year and down at others, particularly for animals which don’t live in the tropics, although even there rainy and dry seasons cause quite a change). For modern humans, who don’t live in anything like a “wild” situation anywhere — not even gatherer-hunters — the average fat is higher, and of course it’s getting crazy in North America. But we also find, for instance, that Eskimos have lower body fat than adults in Canadian cities (people do not gain subcutaneous fat when exposed to cold, AFAIK, would you please send me a reference for that if you have one), and some gatherer-hunter tribes were measured at around 5% body fat, so it’s not unlikely that normal, everyday humans tens of thousands of years ago were not much fatter, if at all, than non-human primates even though they could be, and sometimes were.
In short, when any primate gets fat, the fat which is anchored in internal depots spreads out and under the skin. Due to predation, non-human primates tend not to get that fat, and in zoos they are fed a diet which tries (not always successfully) to keep them trim. BTW, a common thing you’ll see in AAT/H proponents’ claims is the “ten times fatter” claim; this is a serious misreading (originally by Morgan and endlessly repeated by others) of Caroline Pond’s work in which she found that humans, just like other primates, have numerous and small fat cells compared to rodents, that compared to rodents we have “ten times the expected number of fat cells”. She was describing why rodents aren’t a very good model for fat in humans, since they can expand and decrease the size of their fat cells as they get fatter while we, just like other primates, add fat cells instead, and this makes it harder to lose fat since losing fat cells is much harder than reducing their size, yet the small size of our fat cells makes it very hard for them to be reduced in size.
As far as insulation goes, any benefit of fat is secondary rather than a reason it was selected for. And I’ve given an outline of the basic reasons why, and Caroline Pond is one heck of a source, having devoted her career to studying this; your dismissing her work in favor of your wishes is not very good science, to say the least.
Many AAT/H proponents claim that seashore sources are far better than inland sources for DHA (an example is from the BBC Radio 4 program, where it was incorrectly claimed “And the only place to find that accessible and abundant supply of brain selected nutrients was at the shoreline, in the marine food chain.”). This is one of those “true but false” things: One the one hand, DHA itself is found more in some marine sources, but especially in cold water marine fish, which is fairly easy for us to get but let’s face it, impossible for our early ancestors to obtain. But DHA and LNA are found in many inland terrestrial sources, and these are not that hard to find. Wild game, especially brains, various plant fats from various plants (just as you’re promoting flax, and it’s far from the only one) are some sources. And other needed nutrients are, according to studies, far more abundant in terrestrial sources than at the shore.
I was under the impression that the main purpose of fat in the Aquatic Ape theory was not for insulation but in order to help with bouyancy. That in turn would help the ape/human to swim. And it would help with insulation in the water – that’s why women can compete with men in swimming – they have more fat than men do which makes them more bouyant, and they can stay in cold water for longer periods of time than men can for the same reason. Of course, this would not help if they were to stay in water for long periods of time, but the AAT never said that the apes/ humans would live in the water, just that they would live by water sources and spend a frequent amount of time in the water. Also, clearyly other primates can get fat, but can they get as fat as humans can?
And about the fishing – you’re all ignoring another method of gaining marine food that would have been very possible for the apes/humans – diving. There’s not just fish in the sea, there’s also seaweed and crustaceans. It’s very possible that the apes/humans started picking seaweed and custaceans up in shallow water, and gradually moved deeper, learning to dive for their food. They would have then had a ready supply of food much easier to attain than fishing. You can see examples of this in modern times in the Amo and Haenyo diving communities. The women dive in the ocean for food and occasionally pearls. While it takes great skill and training to do this, it wouldn’t be improbable for apes/humans to learn how to do this if they gradually moved out into deeper and deeper water.
There would also be a far greater food supply if they lived off seaweed and crustaceans than if they lived off game and brains, competing with the big cats and other hunters of the area. And if they got bigger brains from eating the same food that terrestrial hunters ate, then why are modern humans brains so much bigger than any brain of a terrestrial animal of the same size? Wouldn’t the terrestrial animals’ brains be the same size in proportion to their bodies as humans? Also, I’m sure those nutrients are found in plants, but would those plants have been found in abundance in that particular part of africa? I don’t know the specific nutrients in plants, but I know that many vegetarians have to be careful about their diet to be sure they get the right amount of vitamens to keep their bodies healthy. That would seem to point that the apes/humans did not get much of the nutrients needed entirely from plants, because then our bodies would be designed for vegetarianism, which they are not. However, I do not know the specifics on that one, so I could be completely off on the plant point. If someone knows more detail about it, please let me know.
Also, the predator arguement against the theory doesn’t hold water, because there would be a similar amount of predators on land. They wouldn’t not go in the water once they had found it to be a good food source because of marine predators, and stayed on land, where there were other predators. It doesn’t make sense. Also, the various aquatic predators would differ from area to area, so they wouldn’t have hippos, crocodiles, alligaters sharks and killer whales diving at them all at once. At most they would have one or two, and they would have learned to cope with them, the same way that they would have learned to cope with the predators on land if they lived in a land based environment. And they probably would not have had to deal with sharks and killer whales unless they lived in the sea, which is unlikely. According to the AAT, they would have lived along the coast, where shark attacks, though they do occur, are minimal.
and, yes, clearly hairlessness would not be as effective in reducing speed as ridges on dolphin skin, but as simply shaving off body hair increased swimmers speed according to a 1989 study, losing thick, curly hair from all over the body would have had quite an effect on increasing both speed and efficiency in the water. If you think about it, it is more likely for an ape to have lost hair in order to be more efficient in the water than it is to have changed its existing hair into the water efficent hair of a seal or an otter. Remember, the ape/human would only be semi aquatic, rather than fully aquatic, so it would have had no reason to grow ridges on the skin like dolphins or other fully aquatice animals. And to assumer that in order for it to be aquatic it would have had to change its pelt into one similar to an otter or a seal is just silly.
ANd yes, humans are instictively afraid of the water. However, we spend quite a lot of time in the water for creatures who are afraid of it. Yes, we have to learn to swim, but we also have to learn to walk, and to speak. What of it? Is language not a part of our brains or our evolution simply because we have to learn it?
OK, I’m done now. I think. Sorry that took so long. You were all giving such intelligent arguements that I had to jump in.
thanks Ilana. If fat provides buoyancy the more fat the harder to dive — which makes it harder to get food that you have to dive for. Insulation is an unequivocal blessing since the water will be cold.
you remind me that collegiate swimmers shave themselves before big meets — to go faster, of course. So even the hair we have left slows us down in the water. This makes the idea that more primate-type hair would be better in the water (fur “aids in hydrodynamics” according to anthroguy) very hard to believe.
Women don’t compete with men in swimming. And as they generally have more fat as percentage of body fat to muscle, I would say that is a hindrance rather than advantage.
Lastly buoyancy is almost irrelevant to swimming speed. Check out the backstroke next time, why is so much of the race underwater off the wall using dolphin-kick? (This is legal BTW)
That is incorrect. Crustaceans and shellfish are extremely hard to find and dislodge from their crevices. On a per calorie expended basis, diving, even with modern spearfishing equipment is a negative proposition. Sustaining oneself or a family is impossible.
These women use all the modern free-diving accouterments (mask, fins, wetsuit, boats, nets, abalone bars to pry abalone off rocks etc etc)
(My guess scuba is too expensive and limits mobility)
Some pics here: https://quebecjeju.blogspot.com/2007/09/dominatrix-women.html
They do NO subsist nutritionally from diving.
This is a complete non-sequitur.
Being in the water and having to face predators negates many of the advantages that humans have. Relatively keen color eye-sight in air/land, being able to aim and throw a spear/rock/club (we know chimps defend themselves with clubs), height to see over obstructions, being able to climb a tree/cliff for evasion and reconnaissance. BTW there are also fresh-water sharks like the Zambezi and Bull Shark that do attack Africans in rivers.
I and maybe a few experienced men with spears have a far better chance against several lions (aren’t lions afraid of the Masai?) than we do against one shark/killer whale/croc/snake/hippo whathaveyou in the water.
In short, they couldn’t have coped.
So it went from a chimp pelt, to hairless, to current status? How and why exactly?
Completely different and irrelvant. All healthy humans learn to, innately/built-in, speak and walk. As birds learn to fly. It is part of the defition of being a human, genetically wired and part of growing.
Swimming is a skill learned, much like driving a car or baking a cake. The baby swimming myth is just that, a myth.
@Seth
So how do you explain the marine mammals I have brought up? Not to mention, the platypus!
Also, feathers on penguins? You have to stop thinking linearly on this. The function probably dips and rises like this:
-No hair — okay/good.
-Some curly hair (especially in very un-hydrodynamic places, head, genitals, armpits) — very bad
-Hydrodynamic thick coat (that may insulate as well — ala sea otters) — very good.
-Ridges ala dolphins/sharks — best.
actually, what you said about the divers is untrue. The ama have been diving for 1,500, before modern technology was created. And traditionally, they do not use modern diving equipment – that has only been introduced recently, in the past hundred years. Traditionally, they would dive mostly nude. In diving communities untouched by tourism, they still dive nude. As for the tools they use to prise the abalone shells from the rocks, those would not be too difficult for a human/ape to come by. They could have used thick sticks. And saying that they would have not been able to live off it is illogical. HUmans have been eating shellfish for thousands of years, long before modern technology came along and made it easier for us to collect. Shellfish mounds have also been found in many ancient cultures. They probably obtained their shellfish through diving, and then swithced to more efficient methods as they became more experienced. But the fact that humans have been eating shellfish for thousands and thousands of years points to the fact that not only could it have sustained a family, but that it couldn’t have been as difficult to obtain as you portray.
Also, the fact that humans learn to talk and walk as well as swim is not irrelevent. In our modern culture, children still have to learn to talk and walk. Therefore, in a culture that lived at the edges of lakes and rivers and on the sea shore, they would have had to learn to swim as well as walk, talk etc… In those cultures, swimming would be “part of the defition of being a human, genetically wired and part of growing,” just like walking and talking is for modern humans.
Bouyancy may be irrelevent to swimming speed, but it is not irrelevent to swimming. And the whole AAT arguement centers around the hominids being efficient in the water. Being able to float would make it easier for them to swim. It also would help them to swim faster, because they could focus more of their energies on moving forward rather than staying afloat.
Seth – you make a good point. However, one of the whole reasons that the Amo and Haenyo cultures use women is because they can withstand the cold for far longer than men because of their fat. This would mean that fat is good for insulation, like you said. But as fat is also bouyant, this bouyancy would not prevent them from diving deep. Again, it is the women, with the most fat, who dive in these cultures.
So humans are able to use their brains to cope with land predators, but the moment that they step in the water, those brains are gone? If early humans can learn to cope with lions, there’s no reason that they couldn’t have learned to cope with water predators as well. At that very least they could have gotten out of the water and climbed a tree (after all, they’re more aquatic than other apes, rather than fully aquatic) Perhaps learning to deal with water predators helped humans/apes gain intelligence? Also, there are many sea based cultures in modern times such as the sea gypsies of southeast asia that must have found methods of coping with sharks and other predators simply because they live so close to the sea. BEsides, sharks would not be the biggest threat, crocodiles would. And not all crocodiles are deadly. In fact, in the area where Lucy was found, the crocodiles are considerably smaller than nile crocodiles and are not a threat to humans. Either the humans/apes would have found a way to deal with man eating crocodiles, and in doing so gained in intelligence and experience, or the water predators where the humans/apes lived were not as threatening as we might assume.
When talking about hairlessness I was referring to our current status. That was what stimulated so much speculation on human evolution, the fact that compared to other mammals, humans are remarkably hairless. (and we stand on two feet). As to why we have armpit, head, and pubic hair, I really don’t know. We probably have armpit hair and pupic hair because they grow in sheltered spots of the body and would not majorly detract from speed and efficiency in the water, or were simply one of the last areas of hair left as the body hair grew thinner and thinner.
Also, when looking at the aquaticness of humans, you have to remember to compare them with apes, rather than fully aqatic animal, or even semi aquatic animals such as otters. After all, Hardy’s original thesis proposed that the aquatic ape would be more aquatic than an ape, and less aquatic than an otter. So is a human’s skin and hair as efficient in the water as a dolphin’s, or a seal’s? Obviously not. But is it more aquatic than an ape’s? Clearly it is. If, according to you, Varangy, a human’s skin and hair is not efficient in the water, than an ape’s would be even less so. Apes do not have hydrodynamic thick coats, so their fur would be even less efficient in the water than our state of relative hairlessness. This only proves the point of AAT – humans are clearly more aquatic than apes, and the only theory providing an explanation for that is AAT.
Sorry, that was long again.
I forgot to mention edible seaweed again in my last post. Sorry about that. Edible seaweed as well as shellfish and fish as well as sponges would provide a lot of food to an ape/human, and edible seaweed certainly would not be difficult to obtain. Oh, and the Haenyo cultures used to live off what they gathered through diving, and it was only when Japan and Korea’s relations improved that the Haenyo divers began exporting their gatherings for cash. So clearly it is possible to live off, and support families, from what could be gathered by diving into the sea. And if it’s possible for Haenyo divers, it was certainly possible for apes/humans as well.
Several points:
The proponents of the AAT/H have tended to go for moving the goalposts when it comes to what features are supposedly for, initially fat was said to be for insulation, then when (valid) objections were made to that claim, they shifted it to bouyancy. They always assume a modern western human degree of fatness, which is problematic, but more importantly they dismiss the sensible idea that features often have side benefits.
As far as predators go, I have a section on my site that deals with predators and there are several big problems with the AAT/H view of aquatic vs. terrestrial predators. One is that we can see how even our most primitive ancestors could deal with terrestrial predators, by looking at how chimps do. Contrary to common AAT/H thought, this isn’t simply by running away and climbing (although those options were available to our ancestors too); mostly they do it by harrassing them, and in fact we see that leopards, for instance, will actually actively avoid chimp groups. Some predation occurs, of course, but we also see that there’s not enough to cause the species to have a significant problem, because they have continued to exist for millions of years in the face of these predators. This shows that a species with similar reproduction to us — medium sized mammals with relatively slow reproduction rates — can survive in a terrestrial environment in the face of terrestrial predators. OTOH, we see no such species in a semi-aquatic or aquatic environment anywhere in the world. This is likely because the situation with aquatic predators is quite different from terrestrial. For one thing, the primary predators — crocs and sharks — are unresponsive to intimidation and counter-attack, very unlike terrestrial predators. And they are numerous. Rather than go over all this here, let me suggest reading that section of my site for the info.
As for hair, it’s quite true that shaving off body hair improves swimming times, and it’s partly due to hydrodynamics (part seems to be due to changes in lactic acid build-up caused by removing the hair), but that only shows the extent of the problem. For swimming speed, we can either shave off our hair or don suits that mimic having lots of hair — the one thing competitive swimmers don’t want is exactly what we have, and what we have is, according to the AAT/H claim, due to swimming speeds and efficiency. If it were, we wouldn’t expect it to be exactly what we don’t want for that purpose.
There are a few other problems I’ve seen pointed out that I haven’t gotten into on my site, such as the littlest, and most deadly, predators: microorganisms, which we find we suffer from in water. We also have a number of ailments due to swimming and diving — the field of sports medicine goes into detail about them — that we would expect to have been weeded out of a species that spent a great deal of time swimming and diving, as those ailments have been weeded out of actual aquatic and semi-aquatic animals. For one example out of many, actual diving species have lost the instinct to breath in when they run out of air underwater; we have the opposite instinct, which is of course rather bad news for us when we’re underwater and know full well we shouldn’t gasp for air but can’t help but do so.
There are a couple other points I realised I should’ve put in my last comment.
First is on the subject of aquatic vs terrestrial predators: one of the bigger problems with the AAT/H claim that predators aren’t a problem for the idea is that unless you’re suggesting an exclusively aquatic species (which no one even halfway sensible is suggesting) they would have to face both types. All their arguments, bogus though they are, about terrestrial predators would apply to their scenario as well, plus the aquatic predators added in. The usual claim there is that the little beasties just run in and out of the water depending on what predator they are avoiding, but this founders for two reasons. One is that terrestrial predators will, and often do, chase their prey into water where their bounding abilities give them an even greater advantage compared to their prey; the other is that aquatic predators are generally not even seen or detected before the attack, while terrestrial predators often are.
The other point is on fat. We see that fat is generally adapted for two things, extra food and — often — body shaping. This body shaping can be sexually selected, as our life history shows it is in humans, or for a functional purpose like streamlining, as it is in whales and seals (the animals the AAT/H says we resemble in this feature, although they don’t like to name them because then it’s obviously ridiculous and the feature is not at all similar in life history). For whales and seals, their fat is adult-like at an early age (at birth for whales), as soon as they hit the water. For humans, we start off fat as babies, go through an extremely lean period as children (except for modern overfed kids), then get remarkably fatter right at puberty. If this was due to water use, whether for insulation or bouyancy, this would mean that babies were aquatic, children weren’t, then we become aquatic again exactly at puberty… and females would be more aquatic than males at puberty. The alternative explanations — unique-among-mammals fatness for our babies as part of our unique-among-mammals extended post-partum development, fat at puberty and variation between the sexes due to sexual selection — don’t have this tortured path to follow.
That’s not true. The big cats stalk their prey – therefore, they, like aquatic predators, rely on not being seen. That is the method by which most predators work, on land or in water.
Also, the predator arguement agains AAH often relies on finding each and every vicious aquatic predator and having them all prey on the apes at once, while they founder in the water. But most aquatic predators that people list would not even apply to the AAH, and it is highly unlikely that even if they did, all the most vicious of these species would happen to exist in the same place that early humans were developing. SHarks, for instance, would not be a serious threat. The amount of shark attacks in shallow waters is very low, even in modern times when we have far more people than existed then. It is still highly unlikely to be attacked by sharks in the water. Even in diving comminuties, the chances of being attacked by sharks is very slim. When it does occur, however, the sharks can usually be deterred by punching or kicking them, which would imply that sharks do indeed respond to threats. There also are documentations of dolphin groups intimidating sharks, which would render your claim, that marine predators do not respond to threats or intimidation or counter attacks, entirely false.
THe primary predator would be the crocodile. However, there is evidence that it would not be as terrible as it is played up to be. There are many species of crocodiles throughout the world, and in only a few areas are they serious man eaters, mainly in the Nile and the marine crocodiles of Australia. However, evidence shows that early humans lived by the Afar sea. The crocodiles in that region are not the man eaters of the Nile or Australia. They probably could be dealt with by humans/apes. Also, crocodiles and alligators jaws can easily be held closed. It is ludicrous to assume that these early humans/apes would not have known about this, yet would have known how to deal with lions.
ANd yes, terrestrial predators will often chase their prey into the water. However, an animal that can swim and dive will have the advantage in that situation, and would probably be able to get away, because they would be more efficient in the water than the terrestrial predator.
I don’t understand your point about shifting goal posts. All theories revise when new evidence is presented. THerefore, what’s wrong about shifting the purpose of fat within the theory to suit new evidence? That’s what’s done in every other theory of evolution, yet when the AAH/T does it, people imply that they are twisting facts, etc… You can’t have it both ways. Such double standards should not exist in science. The same goes for the theory itself. THe AAT/H has been subject to extreme scrutiny, and not one all encompasing flaw has been found, and it still hasn’t been accepted by mainstream science. Yet other evolutionary theories have far more holes in them and are not subject to the same scrutiny. THe theory that apes stood up to better reach fruit is ludicrous, because apes climb trees. Yet apparantly that theory is more scientific that AAH/T. THe theory that apes stood up to see over grass is also implausable, because they would simply return to all fours when they were done looking, if that were the case. I don’t feel like listing all of them right now, but in all of them the disadvantages about becoming bipedal outway the advantages, and they are still more accepted by mainstream scientists than AAH/T. Why does this double standard exist? ANd it’s not because AAH/T is not scientific, because it has far more evidence behind it than many of the other theories. IT even has fossil evidence – many of the early fossils have been found by lakes or in wooded areas that would imply the existence of a close water source, which directly ties in with the AAT/H.
Oh, and about the hair and skin. What we have may be inefficiant when compared to true aquatics, such as dolphins or seals, but compared to apes? Our relative hairlessness would be far more efficient in the water than their pelts. Besides, you’re missing the point. If even a little hair shaved off makes us more efficient in the water, then how much difference must hairloss have made to an ape?
@Ilana
I will respond to your comments later, but with all due respect (this is not a slur), you are not really engaging in logic-based debate and argumentation, rather you appear to be overtly exploring unbound conjecture and trying to fit the data to the hypothesis, when clearly, it should be the other way around.
no, that’s not true, it seems to be that your arguements are in fact illogical. You exploit every scrap of data that would refute the theory, without looking at the theory as a whole. Much of what you have been saying – that all possible extreme water predators would be there to prey upon the apes, that because human skin and hair does not match that of true aquatics – which the theory never claimed – then they couldn’t have possibly spent more time near water than other apes and the theory must be false, seems much more like trying to fit data to refute the hypothysis, rather than looking at all the information out there objectively. However, this is not a slur, and should not be taken as such.
no, I’m not trying to be petty, but the moment you start criticizing me as a person (and yes, you were doing so) goes far beyond having a fun and interesting debate. If you think I am wrong, then say why I am wrong, with facts and reasons, do not start attacking me and calling me illogical.
By the way, I was not ‘exploring unbound conjecture’. Much of what I was saying has facts and reasons behind it. However, since this was merely an interesting debate on the internet, I didn’t bother to site any sources. And of course neither did you. However, if you want me to trace everything I was saying back to a source, then I will.
I am going to make myself very clear. Debates, whether online or in person, are only fun when both sides respect one another. Now, I do disagree with the points you make, and have said why I do so, but I also respect your opinion and can understand why you think the way that you do. Clearly that same respect is not afforded to me, if you have to belittle me and write at me in a condescending manner. (although I did the same to you in this post, thought it was a reaction)
Please, if you feel that I am being illogical, list every point and say in black and white why you think it is illogical. I do the same when I find something to be illogical. But saying in general that my arguements are illogical, that AAT/H proponents arguements are bogus is not really respectful, nor does it make you come across in a positive light, if that’s what you have to resort to merely because you dislike a theory.
That’s not true. The big cats stalk their prey – therefore, they, like aquatic predators, rely on not being seen. That is the method by which most predators work, on land or in water.
We find that chimps just don’t have the huge problem with predators that we might think they would, and they don’t handle predators simply by running away or climbing. Predators mostly avoid them, and the predation they suffer is too little to have kept them from prospering for millions of years. There is no reason to assume that our ancestors couldn’t do what chimps do vis a vis predators.
However, your assumption that terrestrial predators are not seen by chimps doesn’t seem to be how the real world operates. Sometimes sure, but mostly no.
The claim that Afar crocodiles are special friendly non-hominid eating crocs is something started by Morgan, and it founders on several points. First, there is no reason to try to posit that there was an aquatic period centered on Afar; even Morgan has dropped that apparently, and for good reason: we find earlier and earlier fossils in other places. Also, we’re not talking about which crocs now live there, but which crocs lived there in the past. We are also not talking about preying on modern humans (with modern weapons, even “modern” weapons like spears), but preying on our ancestors which is not the same thing (even so, crocodile attacks are numerous and dangerous for reasons I go over in detail on my site). Shark attacks would not, IMO, be as bad a problem, but would be in some areas. The biggest problem for both sharks and crocs, though, is that the attacking animal is generally not seen at all until it has bitten the victim, and then it’s too late. I’m afraid I don’t find the notion of crocodile-wrestling hominids to be anything other than ludicrous. Ditto for your argument that humans are pretty much like dolphins — really, come on…
Also note that today (besides shark fences on many swimming beaches) only a small part of our population is in the water, whereas the AAT/H insists that the entire population used water every day for massive amounts of time — otherwise there’s no selection pressure for these massive changes.
Oh, and about the hair and skin. What we have may be inefficiant when compared to true aquatics, such as dolphins or seals, but compared to apes? Our relative hairlessness would be far more efficient in the water than their pelts. Besides, you’re missing the point. If even a little hair shaved off makes us more efficient in the water, then how much difference must hairloss have made to an ape?
The point it that we have just exactly what swimmers don’t want. We could have no hair and that’s better; we could have lots of hair (like most aquatic mammals) and that would be better. Both those possibilities fit the evidence from sports science. But instead the AAT/H proponent is forced to argue that millions of years of evolution devoted to swimming and diving has left it’s mark on our hair patterns, and done so by leaving us with exactly what we don’t want. That doesn’t make sense. And out hair patterns are rather obviously the result of sexual selection, which is of course another mark against the notion that it’s due to environmental determinism.
I’m afraid the notion that the AAT/H doesn’t have any major flaws is just silly. It has many major, and very bad, flaws.
THerefore, what’s wrong about shifting the purpose of fat within the theory to suit new evidence?
Well, to start with, the fact that the “new” purpose doesn’t fit the facts either.
THe theory that apes stood up to better reach fruit is ludicrous, because apes climb trees. Yet apparantly that theory is more scientific that AAH/T. THe theory that apes stood up to see over grass is also implausable, because they would simply return to all fours when they were done looking, if that were the case. I don’t feel like listing all of them right now, but in all of them the disadvantages about becoming bipedal outway the advantages, and they are still more accepted by mainstream scientists than AAH/T.
These ideas do make sense, although you’ve worded them inaccurately. They not only make sense because that’s when we see other primates using bipedality, but they’ve been tested. Actually, the most common, and long-lasting, use of bipedality is food-getting and carrying. But displays and observation are also very common uses of bipedality. The idea that wading is a major time when bipedality was used is interesting but doesn’t hold up; other than unusual times when wading in very deep water without swimming, what we see mostly is wading while doing food-getting and carrying… so is the wading really the reason, since it’s what they do on land so often too? And the majority of wading time for non-human primates is quadrupedal.
anthrosciguy – thank you very much for pointing out the arguments that you found illogical, rather than just insistantly accusing them of being bogus. However, you do still seem to have some problems with respect, as in almost every peice of writing you have, you consistantly drop in slurs against AAT/H proponents. A word of advice – this lessens the credibility of your arguements, and your standing as an authority on the subject.
Now, in response to what you’ve written: First off, you completely misunderstood the point I was trying to make about the crocodiles. I most certainly did not imply humans wrestling crocodiles. However, if a culture lives by crocodile invested waters, and have to use those waters as a food source, they are going to have to find ways to deal with those crocodiles. When I wrote about holding crocodiles’ jaws shut I was trying to illustrate a known way in which humans could deal with crocodiles, not to suggest that they valliantly went about daily wrestling crocodiles. Also, I was not trying to say that they definitively developed in Afar and that the Afar crocodiles were “special friendly non-hominid eating crocs”, but to suggest that not all cocodiles need be huge man eaters, and that there are crocodiles who are currenlty not extremely dangerous in the North east of Africa where it is likely that early humans developed. I thought I made myself very clear on that point, but obviously I did not. I apologize if you misunderstood me. I also never suggested that humans were like dolphins. I actually have absolutely no idea where that came from. What I actually said what that since dolphins can intimidate sharks, it would imply that sharks actually could be intimidated. Humans are like dolphins never even entered in to that. I did say that the Amo and Haenyo diving cultures dealt with shark attacks by punching them and by intimidation. However, that has nothing to do with humans being like dolphins. Also, the Amo and Haenyo cultures often will see the shark coming – which is why they can deal with them.
AAH does not demand that “the entire population used water every day for massive amounts of time”, and it does not have to be so in order to work. Even for a population that only used water as a food source, and did not enter it for massive amounts of time, selection would still be made to prevent drowning and to increase food getting efficeincy – by swimming, etc…After all, completely terrestrial mammals also have methods to prevent drowning, such as the diving reflex. Why would these selections not have increased in a population that was mostly terrestrial, but which used the water frequently as a food source? AAH does not depend on them practically living in the water, not by the slightest stretch of the imagination.
Hair loss – you’re stressing the point that what we have is exactly what we don’t want entirely too much, especially since it’s not strictly true. That would imply that out of the thousands of different types of hair and fur variations in the animal kingdom, humans have absolutely, catagorically the least efficiant form ever. Of course this is not true. That is not to say that our skin is as efficiant in the water as a dolphins, because it isn’t, not by any stretch of the imagination. You also make the rather simplistic point that hair is good, no hair is good, and what we have is terrible. This fails to distinguish bewteen the different types of hair. Of course an otter’s hair or a seal’s will be extremely efficiant in the water. But a housecat’s will not be nearly as efficiant. What you should be doing is comparing the efficiancy of chimpanzee and bonobo hair – and maybe gorillas and other monkeys for good measure- to humans in the water to see what is more efficiant. The question is not whether humans rank as aquatic in relation to aquatic mammals in the rest of the animal kingdom, but whether they rank as relatively aquatic in relation to apes. That question would easily apply to an ape’s fur. If a reliable experiment is done that says that what humans have is less efficient in the water than even a chimpanzee’s hair, then I will rest my case. However, your answer on hair is sidestepping the issue, and is not fully answering it in the context of the theory (or theories.)
I also have a problem with the notion that our hairloss – practically unique among the animal kingdom – was done by sexual selection. Why would hairloss be sexually selected for humans and not for any other ape? There would have to be a pretty strong reason. I have heard another somewhat similar theory that hairloss would be sexually selected because it would decrease parasites. But why would that be so for humans and not any other ape? All apes suffer from parasites. It would only make sense if humans lived in an environment where parasites were much worse – such as by rivers – for that to work. There has to be a reason for something to be sexually selected. Even in modern human history, there are reasons for what is considered beautiful. Pale skin used to be extremely desired in many cultures up until recently because it showed off a woman’s status, and the fact that she had the luxury of not getting tan through working in the feilds. There are reasons for things to be sexually selected. It seems to me that many scientist – amatuer and professional – rely on the blanket term ‘it must be a sexually selected feature’ for something they really can’t see the purpose of. Of course, things like peacock’s tails really are sexually selected. But I don’t think hairlessness would fall into this category, unless there were other strong reasons accompanying it, because then why don’t apes also have a tendency to sexually select less fur?
I don’t think AAT/H has any gaping holes – minor ones, yes, such as the idea that there was a distict aquatic phase, etc…, but gaping ones, no. I also find that many of the arguments against it are extremely flimsy, or they take the idea to the extreme, or they ‘disprove’ a point by falling back on the same analogies that they hate so much or by providing analogies that don’t really apply yet make them seem as if they do apply. I also think that all the other theories are at least as flawed, or even more so, than the AAH. However, as you clearly disagree with me, and have stated by you do so, let’s let this one drop and not get into a spitting match over it.
No, I did not necessarily word the theories inaccurately, although I didn’t describe them the same way that textbooks etc.. that favor them do. Regardless of whether apes reliably stand up for food getting, it still does not explain why that would provide enough pressure for human ancestors to become bipedal. And the majority of wading time for non human primates is not quadrupedal, it’s bipedal. Where on earth did you get that idea from?
That was long again. Sorry about that.
I thought the Aquatic Ape hypothesis was delightful and intriguing when I first read about it here on Seth’s blog, several months ago. The subsequent comment thread (after that post) thoroughly convinced me otherwise, and left me confused about Seth’s obstinacy in the face of obvious and overwhelming arguments against it.
THIS thread has so thoroughly curbstomped the idea, largely due to anthrosciguy’s contributions, that Seth’s stubborn adherence to it is frankly making me question his judgment about everything, to the point where I’m considering an unsubscribe from his RSS feed. This just isn’t good scientific thinking on display…
@CJ Alexander
THIS thread has so thoroughly curbstomped the idea, largely due to anthrosciguy’s contributions, that Seth’s stubborn adherence to it is frankly making me question his judgment about everything, to the point where I’m considering an unsubscribe from his RSS feed. This just isn’t good scientific thinking on display…
I think this blog is great and I like Seth’s POV on quite a lot. But I know exactly how you feel. I too, as someone who knows a bit about anthropology and has spent more than little time in the water, am surprised, perhaps even a bit appalled as to Seth’s clinging to the very romantic, but highly improbably, theory of AA. But hey, we’re all human.
Sorry to leave a comment so long after the rest, but I just had a couple of points to make for Ilana:
AAH does not demand that “the entire population used water every day for massive amounts of time,” and it does not have to be so in order to work.
That’s what most AAT/H proponents will now say, but then you look at what features they claim are due to this “hardly in the water” lifestyle and you see that those features, like hair, fat, and several others, are found only in a very few fully aquatic mammals which have been fully aquatic for several times longer than hominids have existed. This means they are either actually claiming we spent an enormous amount of time in the water, or that somehow just being near water gave us characteristics found only in whales and serenia. At least Hardy was honest about the amount of time he thought our ancestors would have to have spent in water, but then he was a scientist, even though he did make many elementary errors of fact in his “aquatic ape” idea, just as he did in his telepathy and pyschic phenomena ideas.
The fact is that they also describe those characteristics inaccurately, and they really aren’t like those of aquatic or semi-aquatic mammals, and that’s just an additional nail.
Hair loss – you’re stressing the point that what we have is exactly what we don’t want entirely too much, especially since it’s not strictly true.
Look at aquatic and semi-aquatic mammals; they have either lots (most of the them, the vast majority of them in fact) or none (a very few fully aquatic mammals which have been fully aquatic for several times longer than hominids have existed).
I also have a problem with the notion that our hairloss – practically unique among the animal kingdom – was done by sexual selection. Why would hairloss be sexually selected for humans and not for any other ape?
That’s typically what you see in cases of sexual selection; for instance, why do lions have manes but other big cats don’t? (There is also a tendency toward less body hair in apes, compared to other primates.) But the most critical part is that when you see characteristics like fat or hair being due to environment, an aquatic environment specifically in this case, those chacteristics are set by the time the creature hits the water. Naturally. And they don’t vary between the sexes. Naturally. In humans, however, you find those characteristics change right at puberty and vary between the seses, which are hallmarks of sexual selection. This also leads to the odd internal inconsistency in the AAT/H: babies need to be aquatic to explain their fat, and non-aquatic to explain their larynxes; later, as children, they need to be non-aquatic again to explain their lack of fat and sebaceous glands, and aquatic to explain their larynxes. Women need to be far more aquatic than men to explain their fat and hair differences, but men need to be far more aquatic than women to explain their sebaceous glands. This contradictory jumble just doesn’t make sense, while all those things can be explained simply with non-AAT/H ideas: fat, hair, and sebaceous glands are sexually selected (they near all the hallmarks), the baby fat is unique to humans and no doubt due to our also unique to humans post birth development, especially brain development. And the larynx is now pretty conclusively shown to be due to selection for a deeper voice and is now known to not be unique to humans among primates, not to mention other mammals (others known, so far, include chimps, red deer and elk, koalas, “lions, tigers, and other members of the genus Panthera”, dogs, pigs, goats and monkeys, and even at least some birds, like roosters and cardinals. (It was thought otherwise until recently — 15-20 years ago — because most research on this was done by dissection, but newer research with imaging on living animals shows that the descended larynx is a common feature. And of course until relatively recently we concentrated most research on ourselves, or things of medical benefit to ourselves, which limited our knowledge about a range of non-human animals.)
And the majority of wading time for non human primates is not quadrupedal, it’s bipedal. Where on earth did you get that idea from?
From actual primate researchers’ actual reports on actual primate behavior. That’s what they find. A couple of AAT/H proponents have claimed otherwise, but Morgan did so on the basis of no research whatsoever and counter to the actual research (guess which position I accept?) and another fellow does so on the basis of 5 hours of observation at a zoo where bonobos reached very quickly into water (no more than a few seconds at a time for a total of 37 seconds) where he got radically different results from all other researchers who did hundreds of hours of observations in the wild. He doesn’t wonder at all (as any researcher should) why his results were so far different from everyone elses — other observation of bonobo populations show ranges of 0-24% of wading time done bipedally; and other apes, as well as monkeys, do so even less often. Again, guess which research I find most compelling, the many studies done by many dispassionate observers or the guy who thinks his numbers from 37 seconds of wading should be used in place of all other studies?
Hi Everyone
If people want to find out more about the Aquatic Ape theory there is a 7 part Documentary (Discovery Channel/BBC 1998) of it on Youtube at –
https://uk.youtube.com/watch?v=VFsgtLxALac
Or you can look at Elaine Morgan’s web-site.
https://www.elainemorgan.me.uk/
William Bond
AAT is not about having aquatic ancestors as such, but ancestors
who lived on the shore, as opposed to the savanna. It is about
the role water, waterside living played in human evolution.
See:
AAT – Shore Adaptations in the Genus Homo
https://tech.groups.yahoo.com/group/AAT/
AAT is based on human behavior/anatomy/physiology/DNA
compared to chimps & living animals:
Waterside food collection (fruits/(coco)nuts, turtle/bird eggs, shell/crayfish, water(side)plants, drowned bovids, stranded whales…) explains unique Homo traits (not in apes/australopiths) better than
forest or plains dwelling: brain size, slow-diving skills, breath
control, small mouth & biting muscles, tongue bone descent, projecting nose, poor sense of smell, handiness/tools, late puberty
aligned-spine-legs, flat feet, fur loss, fatness, sweating, reduced
climbing, high needs of water/sodium/iodine/poly-unsatur.FAs(DHA)… features present in different combinations in (semi)aquatic animals
but absent in savanna mammals.
Somebody wants to defend AAT on the basis of:
1. Humans have subcutaneous fat, other primates don’t. Other aquatic mammals do. The fat serves as insulation.
2. Humans have almost no fur, other primates do. Other aquatic mammals don’t. Fur creates drag in the water.
3. Humans are bipedal. Walking upright keeps the head out of the water, allowing breathing.
These 3 arguments can easily be dismissed:
1. Sea otters have no SC fat.
2. They have an extremely dense fur.
3. They’re not bipedal.
And these arguments can be repeated for a lot of other (semi)aquatic mammals.
The point is: most features that discern humans from chimps are *in different combinations* typically seen in waterside mammals that spend a lot of their time in the water: large brain, high sodium, iodine, DHA & water needs, head & spine & legs on 1 line, dexterity & stone use, external nose etc.
Another point is: all H.erectus fossils apparently lay next to shellfish.
It’s obvious that H.erectus did not disperse on “Savannahstan” to other continents as some PA postulate, but along the coasts & from there inland along rivers & lakes. The Mojokerto skull 1.8 Ma lay in marine sediments in a river delta, the Dmanisi population 1.8 Ma lived next to abundant lacustrine resources etc. Why would a destrous intelligent tool-using thick-enameled omnivorous ape not have collected part of his foods from the water, esp.cray- & shellfish??
Many people discussing AAT still think AAT is about australopithecines or human ancestors millions or years ago, but this only shows how uninformed they are.
I suggest that people trying to discuss AAT should first inform properly, eg,
P.Tobias https://allserv.rug.ac.be/~mvaneech/outthere.htm
https://allserv.rug.ac.be/~mvaneech/Symposium.html
https://users.ugent.be/%7Emvaneech/Verhaegen et al. 2007. Econiche of Homo.pdf
https://users.ugent.be/%7Emvaneech/Verhaegen & Munro. New directions in palaeoanthropology.pdf
or google “aquarboreal”
Sorry, there seems to be something wrong with the spaces in the links.
It’s not
but
and
In any case, it’s likely IMO that our semi-aquatic phase was once rather profound (otherwise we wouldn’t be able to dive 50 metres deep & more than 5 minutes), but also that it didn’t last very long (otherwise we hadn’t returned so completely to the land) & that it didn’t happen millions of years ago (otherwise we hadn’t preserved so many (semi)aquatic features).
I guess it happened at some time during the Pleistocene when our ancestral Homo population spread along the coasts (so-called “Out of Africa 1″?), possibly somewhere around the Indian Ocean & not unlikely on offshore islands (SE.Asia? Flores? Danakil? Andamans? …).
During the Ice Ages, sea levels were lower, there must have been large areas on the continental shelves where cray- & shellfish were abundant. These foods have lots of poly-unsaturated fatty acids (DHA etc.) that are essential to brain growth, and that were easily procurable by tool-using & thick-enamel omnivore.
No wonder this phase (100 m below sea level now?) didn’t leave many traces in the fossil & arcaeol.record.
And no wonder their descendant trekked into the continents along the rivers where their diet included cattails (traces on neandertal tools) & where they caught small & large prey in shallow waters & butchered stranded whales & other sea mammals, eg,
– M.Gutierrez cs 2001 “Exploitation d’un grand cétacé au Paléolithique ancien: le site de Dungo V à Baia Farta (Benguela, Angola)” Comptes Rendues CRAS 332:357-362,
– CB Stringer cs 2008 “Neanderthal exploitation of marine mammals in Gibraltar” PNAS 22.9.08.
–Marc
Sorry. Apparently something went wrong again. I hope the correct links are https://users.ugent.be/%7Emvaneech/Verhaegen%20et%20al.%202007.%20Econiche%20of%20Homo.pdf
https://users.ugent.be/~mvaneech/Verhaegen%20&%20Munro.%20New%20directions%20in%20palaeoanthropology.pdf
–Marc
I think too many posters are looking at this the wrong way. If I was to create a simulation on a computer and place two apes on the savanna and two apes on the shores. Which one do you think would survive in each climate. What features would evolution select out as an advantage in the different environments.
The ape who could hold it’s breath, whose nose pointed downward, who had little hair enabling it to dry quickly and not become chilled would have an advantage. Extra fat deposits help as well.
On a savanna, the hairless ape would easily get sunburned, would excrete too much salt (no one has mentioned this tremendous sweating of salt humans do) and water to survive.
To make this post short, I won’t go on, but readers should stop trying to defend theories and start thinking intelligently about what would offer a survival advantage or disadvantage of one ape over another in different environments. Then you will find the right answers.
Well-said, Beard.
‘Aquatic ape’ is an unfortunate misnomer IMO: it’s not about ‘aquatic’, but about ‘littoral’, finding foods at the beach & in shallow water, and it’s not about apes or australopitecines, but about Pleistocene Homo dispersing to other continents along sea coasts & inland along rivers, collecting shell/crayfish, bird & turtle eggs, (coco)nuts, whatever at the waterside. IMO (speculation) this happened (partly?mostly) when during the glacials sea levels were 100 m or so below today’s sea level, when vast continental shelves were available to dextrous tool-using omnivorous human ancestors for beachcombing, wading & diving for sea & other foods. From there different off shoot of these littoral populatons ventrured inland along rivers & lakes, in savannas & elswhere.
Still no answer after more than 2 years? Most people agree?
Recent work on the littoral theory can be found in
M Vaneechoutte, A Kuliukas & M Verhaegen eds 2011 ebook Bentham Sci Publ “Was Man More Aquatic in the Past? Fifty Years after Alister Hardy: Waterside Hypotheses of Human Evolution” with contributions of professor Phillip Tobias, Elaine Morgan & all important proponents of this theory.
Or you can contact me for our recent paper (with Stephen Munro) in HOMO – J compar hum Biol 62:237-247, 2011 “Pachyosteosclerosis suggests archaic Homo frequently collected sessile littoral foods”