Aquatic Ape Theory

Spurious

By standing upright you can traverse deeper water by still walking, decreasing the risk of drowning. Furthermore, the uplift effect of water would have facilitated the transformation to a bipedal posture

ATT's theory of human bipedalism, which maintains that bipedalism was developed to "keep its head above water", though the theory fails to say exactly why this is an advantage. Clearly, though, this can only an issue when the water is relatively deep, say up to the shoulders. (Modern apes have short legs and long arms, leading to a distinct slope of the body when knuckle walking.)

A creature standing upright in this depth of water would have its legs and lower abdomen submerged and wading in this depth is both slow and inefficient because of drag. This would make flight from predators quite difficult. Swimming is a much more efficient form of locomotion in water of this depth and this precludes a bipedal gait. (You can confirm this yourself next time you are in a swimming pool.)

The only animals known to be both bipedal and aquatic are some birds, where bipedalism is a necessary adjunct to the development of wings. Consequently, we have to say that bipedalism is not a known characteristic of aquatic animals.

Lack of Hair

Humans are, of course, not hairless. The hair over most of our bodies is quite dense in terms of follicles per unit area - similar to most apes in fact. However, the hair in most cases is short and fine. In some areas of the adult human body, hair is prominent (pubic and underarm hair) and on the head it is far longer than the hair of any other primate. In many human males, a sizeable mane would cover the entire head were it not for the fashion for shaving and trimming.

The closest to hairless would be cetaceans - whales and dolphins - which are extremely streamlined creatures with a totally submerged, completely aquatic lifestyle. (In fact even they retain cilia which are important to prevent the boundary layer around their bodies from detaching and producing drag. ) Seals are incorrectly cited as being hairless (Ever heard of the fur seal?) and of course creatures such as otters and beavers have fine pelts. On the other hand, rhinoceri, elephants and armadillos are land animals with only vestigial hair.

fat

In reality, the natural human fat distribution is not something about which a great deal can be said in concrete terms. Firstly, we only know fat distribution for modern, relatively obese, Westernized humans. Secondly, we do not know the fat distribution for wild apes, only the obese specimens in zoos. However, we can examine the AAT claims that human fat distribution is characteristic of aquatic animals and that the purpose of human fat is insulation.

Human fat forms a continuous subcutaneous layer. This is a fallacy. Like most mammals, human fat occurs in about a dozen "depots" around the body. In many humans, these depots have expanded and overlapped so that they create the illusion of a continuous subcutaneous layer. However, this is a characteristic of obesity and is not true of all humans. The depot-based distribution is characteristic of all mammals, including the aquatic ones, so it is quite incorrect to say that human fat distribution is characteristic of aquatic animals.

The second fallacy is that the purpose of the fat layer is insulation. This again is based on a widespread fallacy. Surprisingly, there are no animals in which fat plays a significant insulating role. Measurements taken on seals indicate that skin temperature of fur seals is only slightly lower than core body temperature even after prolonged immersion in cold water. It appears that stagnant water trapped in fur is an excellent insulator, and that arrangement of muscle tissues plays a far more significant role.

Furthermore, fat distribution in humans appears unrelated to the heat production of the organs beneath, e.g. there is relatively little fat on the head even though most of the body's heat is lost through it.

 

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"easily accessible, reliable food source (coastal region)... "

easily accessible? in what way? Reliable food sources can be found anywhere that life grows. And it would be a bit tough to actually find easy food sources for an ape-like creature on the coast of the ocean. what would there be to eat? Clams are too hard (needs a bit of intelligence to actually use it efficiently), but perhaps. And there are fish, but no edible plants or large animals. Don't you think the land has quite enough resources for food. Look at the apes in the congo. Natural selection requires the non-reproduction of "less suited" animals, but apes that didn't look for food in the ocean would surely find food on land.

"By aquatic we shouldn't immediately assume totally aquatic. We also might think about it in terms of semi-aquatic. Even though the original idea might have been lamarckian we can still take this notion and contemplate the merits"

Thats reasonable

"One postulation is that by living a semi-aquatic it might have been advantaguous to stand upright instead of standing on four feet."

That would be a very nice reason for the evolution of uprightedness IF we had needed to be in the water and could not swim. These things are, as far as I and the evidence that has been given is concerned, not justfied for happening.

"but it would be unscientific not to examine these notions or not think about them. "

Who says we haven't? This isn't quite a fresh theory.

"Lack of Hair "
___________

Why would lack of hair be an advantage to a sea creature? Streamlinedness? Well, if we could swim, than it might be an advantage, but only in that case. And the uprightedness arguement would break down if you tried to use this.

"fat"
_____

Everyone needs fat. Come on, humans and apes are not the only land animals that have fat in such quantities....

"bipedalism"
___________

A direct effect of uprightedness, so they are linked.

"Voluntary Breath Control "
______________________

I think a much more feasible explanation is that we need to eat though our mouth. If we didn't have voluntary breathing control, we would all mostly choke to death on our food, not on water.

"Descended Larynx"
________________

Again, directly related, but to voluntary breathing control.

"crying of babies"
______________

What about this? I don't know why babies would evolve crying because we live in the sea.... Most mamals have babies that cry. Thus it is an unrelated argument unless you want me to believe that this is now the "Aquatic Mamal, Bird, and Reptile Theory".


Its great that you are thinking about new ideas, but you should not accept them without substantial evidence that is relevant. So far, even if this theory explained all those things you listed, you still have not given us a good advantage for living aquatically.

 

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Human bipedal running is both slower and less energetically efficient for running than is chimpanzee knuckle-walking

However, for normal walking locomotion, for instance from one food source to another, human bipedal walking is more energetically efficient than is chimpanzee knuckle-walking

Bipedalism would confer an adaptive advantage especially in times of low food availability and sparse distribution of food resources

Bipedal humans would expend less energy to move from patch to patch of food, and would get there faster on average than knuckle-walking early pongids

In a changing environment such as that found at the close of the Miocene, food resources became more sparsely distributed as forests shrank and expanded

The ability to move from one forest patch to another efficiently would have been adaptive

Bipedal hominids would have been well suited to do this
<table border="1" cellpadding="0" cellspacing="0">
<tr>
<td align="center" colspan="4" width="394"><b>Energy
Efficiency</b></td>
</tr>
<tr>
<td align="center" width="106"><b>Walking speed</b></td>
<td align="center" width="72"><b>Species</b></td>
<td align="center" width="102"><b>Energy cost ml 02/kg/hr</b></td>
<td align="center" width="114"><b>Energy cost relative to
quadruped</b> </td>
</tr>
<tr>
<td align="center" width="106"><b>2.9 km/hr</b></td>
<td align="center" width="72"><b>Chimp</b></td>
<td align="center" width="102"><b>0.522</b> </td>
<td align="center" width="114"><b>149%</b></td>
</tr>
<tr>
<td align="center" width="106">&nbsp;</td>
<td align="center" width="72"><b>Human</b></td>
<td align="center" width="102"><b>0.193</b> </td>
<td align="center" width="114"><b>86%</b></td>
</tr>
<tr>
<td align="center" width="106"><b>4.5 km/hr</b></td>
<td align="center" width="72"><b>Chimp</b></td>
<td align="center" width="102"><b>0.426</b> </td>
<td align="center" width="114"><b>148%</b></td>
</tr>
<tr>
<td align="center" width="106">&nbsp;</td>
<td align="center" width="72"><b>Human</b></td>
<td align="center" width="102"><b>0.170</b> </td>
<td align="center" width="114"><b>94%</b></td>
</tr>
<tr>
<td align="center" colspan="4" width="394"><b>2.9 km/hr is
normal knuckle-walking speed of chimps, 4.5 km/hr is
normal bipedal walking speed of humans (Rodman and
McHenry 1980)</b> </td>
</tr>
</table>
</center></div>
(dr bindon)

?

 

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enhanced mobility

I would suggest that instead of thinking of African apes as being bipedal, it would be better to think that they had an unspecialised form of locomotion similar to that of Orang Utans. Orang Utans do not come to the ground often, but when they do they get around sometimes by fist-walking and sometimes by ungainly upright walking.

If you can imagine an ape like an Orang Utan, sleeping in trees and spending much of their time in trees but coming to ground occasionally, this could be a model of early African apes. This would be similar to the life-style of some lowland gorillas today. Lowland gorillas are tempted into bais in the rainforest, which are areas of open but often swampy ground, to feed on the abundant aquatic vegetation. However, early African apes would not have been good cellulose-digesters like modern gorillas, but would have been tempted down from the trees by the starch-rich roots of aquatic plants.

Never having to walk long distances and often having to wade in an upright posture, this unspecialised form of locomotion would have been quite adequate for their purposes. One population would have specialised in drier ground and became the ancestors of the gorillas. Needing a more efficient mode of locomotion, they became knuckle-walkers. Later the ancestors of the chimpanzees became another offshoot, and followed a similar path.

This left our ancestors, who when they expanded out of the marshy conditions were now so adapted to an upright condition that it was natural that they should adopt bipedalism instead of knuckle-walking as their mode of locomotion. Even so, the Australopithecines continued to sleep in trees and continued to spend much time on the flood plains of East African rivers like the Awash.

Early Homo would have been more wide-ranging and would have developed bipedalism to the efficient form that we see today. Homo would have continued to wade when necessary but would also have developed swimming and diving skills. They would have done this not only to get food but to move across a landscape and survive flooding. They would have exploited not only rivers but also lakes and the sea.

The last common ancestor of humans and chimpanzees was 5 or 6 million years ago. It is only natural to suggest that it was this time that was the most significant for human evolution. However, it could be that this age was of no importance, and nothing of any great significance occurred. Instead, two other times were important. One was 10 or 12 million years ago and the other was 2 or 2.5 million years ago. The first was the time when an ape similar to the Orang-Utan started coming down to the ground regularly to exploit a wet landscape. The other was when early Homo became fully bipedal and exploited marine and grassland habitats, possibly with a seasonal migration. The Australopithecines probably lived pretty much like their ancestors, and some lowland gorillas today. 10 million years or so that our ancestors spent living like this, wading around a wet landscape, could be seen to be a preadaptation to the marine exploitation of Homo.

Whatever the origins of bipedalism, it seems likely that at some point bipedal apes would have been in competetion with quadrupedal apes. Our ancestors would have been in competition with the ancestors of chimpanzees. Bear in mind that early bipedal apes like Australopithecus were very similar to chimps except they were bipedal. How is it that bipedalism survived, given its obvious disadvantages. This is a question that Elaine *Morgan and Marc *Verhaegen fail to address.

Bipedal apes could not run as fast as quadrupedal apes. They were not as good climbers. So it would have more difficult for them to avoid predators. However, bipedalism is more energy efficient at walking. If our ancestors made use of their ability to walk long distances then they could have competed against the chimps. So I think that Australopithecus and sister genera were wide-ranging generalists. Also, they would have continued to have an advantage in watery environments like flood-plains. (andrew lewis)

 

east african habitat

There are two views about East Africa

1. East Africa was once covered in rain forest of the type still seen in west and central Africa. During ice ages it became drier. Rainfall decreased 5 million years ago and even more 2.5 million years ago. Five or six million years ago, when the first hominids - Ardipethecus and Australopithecus - appeared, there was not much savanna.

2. The mosaic of grassland, woodland, and patches of forest which exists today has characterised the region for at least 15.5 million years. See *'Africa A Biography of the Continent' by John *Reader, page 52.

There are three ways of viewing East Africa today.

1. A vast grassland plain.

2. Zones or belts of vegetation of different types, dependent on differences in rainfall, from woodland to grassland to desert.

3. A mosaic patch-work quilt of vegetation of different types.

All three views have their value, but the third is the most correct, especially of the Rift Valley where most hominid fossils have been found.

The boundaries between adjacent vegetation zones are extensive. Bernard *Campbell in his book *'Human Ecology' writes about the boundary between forest and woodland, what he calls the 'forest/woodland ecotone'. He explains that this boundary is very extensive due to natural irregularities of altitude and rainfall, and by the presence of forest along the river beds which cross the more open plains. He says that a species living at the junction of two biomes can exploit two sets of resources, which is especially important during a time of seasonal dearth of food in one of these biomes. Woodland, as distinct from forest, is seen by many as an important biome for hominids. What is true of the forest/woodland ecotone is true of other ecotones.

People have pondered which habitat produced our ancestors and ultimately us. As generalists, our ancestors were more likely to have inhabited an ecotone between two vegetation zones than one zone or habitat. They are even more likely to have inhabited a region where many zones and many ecotones are found together. This would be in the flood plains of east African rivers where so many hominid fossils have been found. Here gallery forest is found along the rivers and especially in the bends of the meanders and the islets between the branches. Woodland and grassland would be further away from the river. The sides of the valley would have another vegetation type. True mosaic. Trying to say which habitat or vegetation zone hominids were in is a futile task, because of the concept of ecotones and flood-plain mosaic. Migration is another complicating factor. Also, we should be talking about population densities for different regions, not where they were and where they weren't.

Flood plains did not only exist on the coast. This is what John *Reader has to say about it in *'Africa A Biography of the Continent' by, page 73.

At times the ancestral Omo flowed through the basin and east to the Indian Ocean ( a connection which is confirmed by the presence in the Turkana deposits of fossilized ocean fish remains, such as the teech of a stingray). At other times its waters remained in the basin in the form of rivers flowing down the length of the basin like tangled braids of hair, meandering through gallery forests and woodland; creating floodplains and ephemeral lakes.
Nina *Casimati in her book *'A Guide to East Africa' writes eloquently about Lake Manyara National Park and Serengeti National Park and their many distinct vegetation zones.

This is the kind of complex region that in my opinion is the most likely to have evolved hominids. (andrew lewis)


A quick background to the Pliocene

 

more speculation

i think they said this because some ape/monkey species show the tendency to walk upright through water, even if it is not strictly necessary. I guess they took this example a step further.

now some major speculation from my part.
i guess that the advantage of keeping your head above water must lie somewhere in risk reduction. Increased length increases your safety zone. It might also cost less energy (for a non-aquatic animal) to stand in water compared to swim in it.
but i don't really know.

The main problem is with dismissing this theory is that the evidence for the accepted theories isn't that great either. They do had the benefit of being published first and we all know how difficult it is to change an accepted dogma.



some comments on Frencheneesz then. I'm not going to bother to do them all, since it is not my frikking theory.

i think that the sea or a lake is quite a rich source of proteins. You might know that protein rich food is more nutritious as vegetation. Hence there could be some kind of advantage.

the difference is that our fat is sub cutaneous, similar to aquatic animals. Unlike any other ape or monkey...or non-aquatic mammal (as far as i know)

except that most animals don't have this and still have to eat. Personally i think that this particular feature has something to do with the advent of speech and not the putative aquatic lifestyle.

of course, as long as we keep in mind that there is no real definite evidence for the other theories either. Hence it seems it bit silly to trash this one for no good reason.

and of course spookz gave us a quite a good view on the current ideas and i feel that I now might have undone his good work by posting my petty nonsense.

 

Hominid lifestyle and diet reconsidered:

This wet scenario requires no great evolutionary steps. Forest-dwelling herbivores like capybaras, tapirs or pygmy hippos are partially adapted to the water collections in the tropical or subtropical rain or gallery or mangrove forests, but remain four-legged. In these shallow waters, primates - which, because of their arboreal history, have very mobile joints and a tendency to body erectness - easily adopt a bipedal stance and gait. Lowland gorillas go wading on their hind legs through swamps to get edible sedges and AHV (Chadwik, 1995; Doran & McNeilage, 1997). Proboscis monkeys Nasalis larvatus cross stretches of water on two legs to reach other mangrove trees (Morgan, 1997; Ellis, 1991). Japanese monkeys Macaca fuscata on islands walk bipedally into the sea (e.g. Morgan, 1997).

In mangrove swamps, lower tree parts are occupied with bivalves, which are exposed at low tide (Fernandes, 1991). No doubt, inventive inhabitants of such places began to exploit these rich food sources, just as capuchin monkeys do, who feed on crustaceans and oysters. These relatively large-brained primates even use oyster shells to crack other oysters when no stones are available (Fernandes, 1991). Probably, human ancestors, who already cracked hard-shelled nuts and fruits with stones, used pebbles as tools, at first for opening shellfish and later for processing other food sources like carcasses of hippopotamuses (e.g. Bunn, 1981). Once they mastered how to cut through skins with sharp stones or to use stone tools for processing wood, they would have seen new niches open to them, encouraging them to invade the inland along the rivers.

Physiological data make it very probable that the phase of partial shellfish collection at one time included frequent diving (Schagatay, 1996). Today, human populations all over the world still collect shellfish or seaweed through diving. It could perhaps explain some human parallelisms with sea-mammals, according to the ideas of the so-called aquatic hypothesis of human evolution (Westenhöfer, 1924, 1942; Hardy, 1960; Morgan, 1982, 1990, 1997).

Among these adaptations, those for diving and breath-holding (Schagatay, 1996), in combination with an older sound production as in many arboreal animals like gibbons (Darwin, 1871), could have led the basis for the voluntary and articulate sound production of human speech (Verhaegen, 1997). In this respect, Derek Ellis (personal communication) remarks ëhow well sound travels over water, compared to being muffled in forests, and even compared to grassland. Foraging beach and lagoon apes could separate quite widely and still remain in contact by vocalisingí.

Although both Australopithecus and Homo species seem to have dwelt at the edge between land and water, the differences in paleo-milieu, dentition, tool use and brain size suggest that both had different lifestyles. Nevertheless, there is a completely natural sequence of small behavioural innovations that could lead from early australopithecines to modern humans (points 2 to 5 are seen in chimps or gorillas, see Yamakoshi, 1998; Chadwik, 1995; Ellis, 1991; Nishida, 1980; Golding, 1972).

* frugi- and herbivory in tropical forests (all hominoids),
* using stones to crack hard-shelled fruits and nuts,
* frugi- and herbivory also in forest clearings,
* plus ìshortî-legged bipedal wading in shallow waters,
* plus more frequent surface-swimming,
* wading and swimming also in mangrove forests,
* plus feeding on bivalves growing on lower tree parts,
* using shells or stones to crush shellfish,
* using stone tools for various purposes,
* colonising the seashores and rivers as omnivores,
* re-invasion of the land along the rivers,
* long-legged bipedalism on land.

Conclusion
The combination of comparative, physiological and paleo-environmental data makes a savanna evolution improbable, but does not exclude a temporary evolution of human ancestors and relatives at the edge between land and water. Many human features cannot be explained by a history of tree or forest dwelling alone, but find convergences in primates that live in mangrove areas, such as proboscis monkeys and some tufted capuchins. The paleo-environmental and dental data suggest a gradual evolution, in strongly overlapping phases, from frugi- and herbivores in gallery or tropical or mangrove forests to ìshortî-legged bipedal waders in forest clearings or mangrove swamps, to omnivores and partial shellfish feeders along seacoasts and rivers, and finally to long-legged bipedalists on land._(Marc Verhaegen)


Hominid lifestyle and diet reconsidered

river apes

 

Spookz

Forest-dwelling herbivores like capybaras, tapirs or pygmy hippos are partially adapted to the water collections in the tropical or subtropical rain or gallery or mangrove forests, but remain four-legged

Of course, they are plainly terrestrial, as are we.

Physiological data make it very probable that the phase of partial shellfish collection at one time included frequent diving (Schagatay, 1996). Today, human populations all over the world still collect shellfish or seaweed through diving. It could perhaps explain some human parallelisms with sea-mammals, according to the ideas of the so-called aquatic hypothesis of human evolution

Nonsense. Throw a dogs favorite chew toy in the deep end of a swimming pool and watch the dog dive down to the bottom and retrieve the toy. According to the theory, the dog must also have evolved with sea-mammals.

The combination of comparative, physiological and paleo-environmental data makes a savanna evolution improbable, but does not exclude a temporary evolution of human ancestors and relatives at the edge between land and water.

I'm inclined to consider the Savannah theory has more validity than ATT, but that doesn't mean I think Savannah is correct either.

The paleo-environmental and dental data suggest a gradual evolution, in strongly overlapping phases, from frugi- and herbivores in gallery or tropical or mangrove forests to ìshortî-legged bipedal waders in forest clearings or mangrove swamps, to omnivores and partial shellfish feeders along seacoasts and rivers, and finally to long-legged bipedalists on land.

So, why are there no other semi-aquatic animals that developed bi-pedalism ?

Spurious

The main problem is with dismissing this theory is that the evidence for the accepted theories isn't that great either. They do had the benefit of being published first and we all know how difficult it is to change an accepted dogma.

The Aqua-ape theory is fanciful and fun, and there's just enough "sciency" stuff to wow any layperson. But the underlying premises are ALL refutable and the logic fallacious. THAT is why it is dismissed as whimsical by all reputable paleoanthropologists.

If you think AAT is serious science, you are kidding yourself. It is not even mentioned, except for the purpose of refutation, in mainstream peer-reviewed literature.


btw - The main proponent of ATT, Elaine Morgan, was a television screenwriter with no post-graduate education.

 

q

the verhagen and lewis quotes were mainly to give an idea on the conditions that existed at the time primates were supposedly aquatic. from what i understand it was a period of increasing temps and shrinking woodlands.

also take note aat is getting watered down from the homo's being water dwellers to simple waders. eg the hybrid theory......semi-aquatic..

the savanna scenario seem less plausible than a wetter one for the simple reason that there would be more food available in the latter. but then again why has there to be a choice in habitat? perhaps both were populated?

the main controversy is adaptations and i thought that had been resolved.

shit from the straight dope

". . . [T]he exceptional ability of Man to swim . . ." Not very exceptional. Hardy admits "many" animals can swim on the surface. In fact, almost all terrestrial mammals can. With very few exceptions, adult mammals, when introduced to the water for the first time, can swim without any previous training. This is largely because they tend to float horizontally and are able to keep their nostrils above water. Apes and humans, on the other hand, tend to float vertically with their nostrils submerged. Humans (and at least some apes) can learn to swim, but it doesn't come naturally. Based on this point alone, hominoids would appear to be among the least likely mammals to return to the water.

". . . I have been told that babies put into water before they have learnt to walk will, in fact, go through the motions of swimming at once . . . " Partly true, but misleading. Babies, placed face down in the water, can hold their breath and rather inefficiently propel themselves through the water. Their motions are as much like crawling as they are like swimming. Babies cannot, however, lift their nostrils above water unassisted to breathe, which would seem to make their much-vaunted "swimming" ability worthless. Nor are human infants unique in being able to propel themselves through the water; the young of many, probably most, terrestrial mammal species can do the same.

"Does the idea perhaps explain the satisfaction that so many people feel in going to the seaside, in bathing, and in indulging in various forms of aquatic sport?" Uncertain, probably unverifiable, and more than a little silly. One of my neighbors had a trampoline in his back yard instead of a pool. Was he trying to recapture the days when our ancestors' bottoms were made out of springs? Are we Tiggers or are we men?

"Whilst not invariably so, the loss of hair is a characteristic of a number of aquatic mammals . . ." True, if you take "a number" to mean "a small number." Fur or hair is no great hindrance underwater. Fur seals, otters, beavers, and polar bears haven't lost theirs and they swim better than we do. Only some aquatic mammals have lost all or most of their hair, and they are almost invariably very large species weighing a ton or more, whose ancestors have been living in the water for tens of millions of years. Contrary to popular thought, fur remains an effective insulator even in water, because it traps a layer of stagnant water (or in the case of the sea otter, air) next to the skin. Further, our ape relatives generally have sparse hair, though not quite as sparse as ours. What do AAH supporters make of relatively hairless terrestrial species, such as the elephant, rhinoceros, and pig? They postulate an aquatic past for them as well. It just goes to show that you can explain away any inconvenient fact if you try hard enough. The real reason these species, including humans, lost their hair was to dissipate heat faster. If anything, we lose heat too fast when we're in the water (even tropical water), which should have made us retain our fur if we were really aquatic.

"All the curves of the human body have the beauty of a well-designed boat. Man is indeed streamlined." There's a big brown stain on this page of my copy of Morgan's book because when I first read this, I laughed out loud with a mouth full of coffee. Truly aquatic animals are shaped a lot like torpedoes. Let me know the next time you see a torpedo with long flowing hair, a slender neck, rounded shoulders, and enormous knockers. See if you can get her number for me first.

"The presence of . . . subcutaneous fat is a characteristic that distinguishes Man from the other primates." It is true that many aquatic animals have a thick layer of subcutaneous fat, but not, as Hardy supposed, for insulation. Their subcutaneous fat is mostly for streamlining and energy storage. Fat is a much poorer insulator than it is popularly thought to be, and poorer than fur even underwater. Of course sedentary western humans tend to be fat, but they are not a fair representation of humans. Even so, it must be admitted that the human species, even hunter-gatherers, are probably quite fat compared to most other terrestrial species. Most likely this is due to self-domestication. Animals who no longer need to fear predators, including man and his domestic animals, have become much fatter than their wild relatives. The same is true of hedgehogs, whose natural protection renders running away unnecessary. Is the distribution of subcutaneous fat in humans somehow exceptional? Not at all. Sedentary zoo apes on a high-calorie diet accumulate subcutaneous fat stores in exactly the same places we do. What is exceptional is the difference between human and aquatic subcutaneous fat. Truly aquatic animals have thicker layers of fat surrounding the whole body. In humans, the fat layer is thinner and, on parts of the body, non-existent.

"It seems likely to me that Man first learnt to stand erect in the water . . ." The idea here is that a primate tends to stand erect when wading in water, if it's deep enough. That's true, but it's not the whole story. Gorillas, bonobos, and chimpanzees all stand and walk on two legs occasionally when on dry ground. Their normal means of locomotion is knuckle-walking (i.e., walking on all fours with the knuckles of the hands on the ground rather than the palms). But the interesting part is the other apes: the orangutans and gibbons. Their normal means of locomotion is brachiating (swinging from branches). On those rare occasions when brachiators come down to the ground, they usually walk on two legs, like humans. There is a growing school of thought that the last common ancestor of humans and chimps was a brachiator and not a knuckle-walker as had been previously believed. This would require that knuckle-walking evolved twice (in gorillas and chimps) rather than once, an idea that not all experts accept. A fossil species called Oreopithecus ("swamp ape," not "creme-filled chocolate cookie ape") is cited by AAH supporters as an example of a primate that learned to walk upright by first wading in swamps. It is much more likely that Oreopithecus was a brachiator than a wader. It's worth noting that no aquatic species regularly walks on two legs when on land.

"Where are the fossil remains that linked the Hominidae with their more ape-like ancestors? . . . It is in the gap of some ten million years, or more, between Proconsul and Australopithecus that I suppose Man to have been cradled in the sea." It wasn't until recently that we knew how wrong Hardy was on this point. Since he wrote it in 1960, the gaps have been progressively filled in, most famously by Lucy in the 1970s. In late 2000 a specimen dubbed Millennium Man (Orriorin tugenensis) was discovered in Africa. It must have lived very close to the time when humans and chimpanzees diverged and fills in another important gap. It appears to have already developed upright walking, but also retained some climbing adaptations. The fossil gaps up to the last common ancestor of chimps and humans are now measured in hundreds of thousands of years rather than Hardy's tens of millions. Oddly enough, Morgan has used this point as an argument in favor of the AAH. She suggests that the gaps are so short that only something as revolutionary as an aquatic stage could account for the changes. OK, but when two contrary facts are both used in support of a hypothesis, alarms go off. Besides, the evolution of human features displayed by the fossils appears to be reasonably gradual, not abrupt. None of the fossils suggest an aquatic lifestyle.

fairly satisfactory, wouldnt you say q?
just for the fun of it i am gonna try hook eskimos and pacific islanders to one or more variations of aat. oh.. oh... how about a marsh dwelling amazonian aquatic indian?

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is diving and catching fish part of a dogs natural behaviour. (wild dogs that is)
i am sure wolves fish (dependant on habitat of course)

So, why are there no other semi-aquatic animals that developed bi-pedalism ?

dunno, maybe different species have different evolutionary lines?

aat was hardy's theory (marine biologist) morgan merely milked it for all it was worth

 

could you sum up the evidence that supports the other side of the story?
I can't...maybe that is why i'm not particulary wowed by any of these theories.

i'm assuming there isn't that many evidence, since lifestyles don't fossilize that well and the fossil record of human evolution is quite sparse....but at the same time i must admit that i never bothered to look into this matter.

in conclusion: I'm just saying that the evidence for both camps is quite meager, hence i'm not willing walk on fire for any of these theories. On the other hand a modified AAT could be quite elegant and I like elegant theories. It's not illegal to be creative in science.

the truth lies always in the middle

edit: it seems that the debate is not over yet in science...a search on ISI reveals still articles.
latest:
Aquarboreal ancestors?
Verhaegen M, Puech PF, Munro S
TRENDS IN ECOLOGY & EVOLUTION
17 (5): 212-217 MAY 2002
Abstract:
According to biomolecular data, the great apes split into Asian pongids (orang-utan) and African hominids (gorillas, chimpanzees and humans) 18-12 million years ago (Mya) and hominids split into gorillas and humans-chimpanzees 10-6 Mya. Fossils with pongid features appear in Eurasia after c. 15 Mya, and fossils with hominid features appear in Africa after c. 10 Mya. Instead of the traditional savannah- dwelling hypothesis, we argue that a combination of fossil (including the newly discovered Orrotin, Ardipithecus and Kenyanthropus hominids) and comparative data now provides evidence showing that: (1) the earliest hominids waded and climbed in swampy or coastal forests in Africa-Arabia and fed partly on hard-shelled fruits and molluscs; (2) their australopith descendants in Africa had a comparable locomotion but generally preferred a diet including wetland plants; and (3) the Homo descendants migrated to or remained near the Indian Ocean coasts, lost most climbing abilities, and exploited waterside resources.

didn't bother to read it...but apparently not everybody in science thinks it is completely crackpot as some people suggest...
unless these authors are also crackpots...i know for a fact that this is not uncommon in science.

 

Spookz

fairly satisfactory, wouldnt you say q?

Very good! Many of the claims made by proponents of AAT can easily be shown to be false. Here's another excellent critique:

http://biology.uindy.edu/Biol345/ARTICLES/umbrellas.htm

aat was hardy's theory (marine biologist) morgan merely milked it for all it was worth

Prior to Alister Hardy, a pathologist, Max Westenhofer included a chapter in his book Der Eigenweg des Menschen on the underlying principles of AAT. And although Westenhofer was not a paleoanthropologist, he soon abandoned the theory. Since then, no publishing proponent of AAT has been taken seriously by scientists.

And of course, one should never take seriously half-baked theories from a television screenwriter (ie.Elaine Morgan.)

Spurious

could you sum up the evidence that supports the other side of the story?

Could you be more specific. AAT and Savannah for example are not the only competing theories. There are others as well, among them are:

"Regional Continuity" model, the "Multiregional Evolution" model and the "African Origin" model. The African Origin model has three competing subtheories:"Replacement", "Weak Garden of Eden" and "Multiple Dispersals".

And so on...

I'm just saying that the evidence for both camps is quite meager, hence i'm not willing walk on fire for any of these theories. On the other hand a modified AAT could be quite elegant and I like elegant theories. It's not illegal to be creative in science.

It should be noted that paleontologists completely ignore the AAT simply because all claims made by proponents of the theory are shown to be false. You'll also find that the AAT is only published in journals which are NOT peer reviewed; such as The New Scientist, for example.

didn't bother to read it...but apparently not everybody in science thinks it is completely crackpot as some people suggest...
unless these authors (Verhaegen M, Puech PF, Munro S) are also crackpots...i know for a fact that this is not uncommon in science.a

You got that right!

 

Aquatic Ape?

I think here's your guy!

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Monkey:

"i think that the sea or a lake is quite a rich source of proteins. You might know that protein rich food is more nutritious as vegetation. Hence there could be some kind of advantage. "

I suppose, but thats a bit vauge, but what happened to that advantage to make people leave the water?

"the difference is that our fat is sub cutaneous, similar to aquatic animals. Unlike any other ape or monkey"

Could you explain "sub cutaneous"? As far as I know, our fat system is much the same as any other mamal.

"except that most animals don't have this and still have to eat."

Most Animals with lungs (all that I know of) have the ability, can you give me an example of an animal with lungs that doesn't have voluntary breathing control.

Sure sure, its not your theory. But the idea is a bit zanny don't you think? And the evidence isn't all that conclusive either. Why would we loose hair? Well, why does some cats have no fur? Its simply because we are different, and we happened to have good traits along with the weird no fur trait. Diversity will happen as long as the traits aren't harmful.

 

We were aquatic !

I am sorry I came late at this topic, but better late than never.

Elaine Morgan was mentioned several times and I am not sure if anybody commented on her masterpiece DESCENT OF WOMAN.
In the book she brilliantly exposed aquatic theory explaining the origin of speech and other traits that makes us so much different from other apes. A million years in shallow waters made crucial difference.

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Trends in Ecology & Evolution
looked up the journal...it had an impact factor of 10...that is not that bad actually...My last article only went to a journal with impact factor 8. Most researchers are even happy with a lot less.

I did notice that the article was under the opinion sector and i do not know if it has been peer reviewed, but i really doubt it if they would publish something like this if it was really unscientific and crackpotty...
The fact that I found other articles supporting this theory (or better put, parts of this theory) gives us some indication that we might assume that the entire matter is not as unscientific as some people suggested.

isn't that interesting...so many theories...the presence of many theories in science usually indicates a high degree of uncertainty.

My conclusion would therefore still stand. This matter is far from settled and there is no conclusive evidence for any of these theories. Which one do you like personally???

 

i guess that is not clear, but let's recap what the thought is about a semi-aquatic life style.

during a certain period of the evolution of hominids a species chose (for some reason) to adopt a semi-aquatic lifestyle. This could have been a cultural event. We know for instance that chimpanzees groups all have different habits which they pass on from generation to generation. Maybe one ancestor group had the habit of spending lots of fouraging time near water. Because of this there was a selective pressure for phenotypic characteristics that suited this environment. Maybe these particular hominids were succesful in a certain area. Maybe this ensured that there was a continued selective pressure for a prolonged period of geological time. maybe this was the time when earlier mentioned features developed.
Then this era ended. These hominids were successful and started spreading to different environments. For what reason? maybe they could outcompete other species in environments in which they couldn't before. And then they spread and the selective pressure for the pure aquatic features disappeared.

It has been a long time ago, so I might make a few mistakes in my explanation. Most animals tend to store excess fat in the abdomen. Hence a fat gorilla still has lean looking arms. We store a lot of fat under the skin (hence) the fat arms of a fat person. Some people attribute this to an aquatic adaptation...but then again, pigs store quite a lot of fat here and are not aquatic.

but in the end you might be able to discredit each feature, because other terrestial animals have similar features, but i guess what lots of people found intriguing is that humans have many of these features combined in one species.

quote:



Originally posted by Frencheneesz

"Voluntary Breath Control "
______________________

I think a much more feasible explanation is that we need to eat though our mouth. If we didn't have voluntary breathing control, we would all mostly choke to death on our food, not on water.
[/B]

We can for instance choose to breath with our mouth or our nose. A dog would always breath in through the nose and out through the mouth. I don't know in how far other animals can choose not to breath. I have seen dogs pick up things from under water, so they must be capable to hold their breath. Maybe it is a degree question. To what degree do you have volentary breath control. But personally I don't think that this is one of the stronger points...

 

Spurious

I did notice that the article was under the opinion sector and i do not know if it has been peer reviewed, but i really doubt it if they would publish something like this if it was really unscientific and crackpotty...

You will not find the AAT in any peer reviewed journals except when used for refutation. The theory has been shown to be false, therefore it is ignored, just like any other crackpot theories.

The fact that I found other articles supporting this theory (or better put, parts of this theory) gives us some indication that we might assume that the entire matter is not as unscientific as some people suggested.

The AAT has been around for almost 75 years - it is not a starter hypothesis. In any case, a number of crackpots have leagues of followers who also write articles supporting their hair-brained theories, scientific or otherwise. That doesn't make the theories any more valid or credible especially when the theory has already been proven false, as is the case with AAT.

isn't that interesting...so many theories...the presence of many theories in science usually indicates a high degree of uncertainty.

Why would you say that ? A sceptic would see that as a high degree of crackpots trying to undermine accepted theories with their own nonsense.

My conclusion would therefore still stand. This matter is far from settled and there is no conclusive evidence for any of these theories.

You may conclude whatever you wish. But the AAT has been settled. Elaine Morgan, Marc Verhaegen, et al. are crackpots every much as people like Nancy Leider, Tom Bearden, Richard Hoagland, etc.

Did I also mention that Elaine Morgan is not a biologist, she is a television screenwriter.

Here's something to think about. When the semi-aquatic population returns to land, by what Darwinian mechanism are they able to out-compete the population that never became semi-aquatic in the first place?

This terrestrial population had allegedly 1.5 million more years on land to become ultra-specialized at terrestrial living.

To reason that the semi-aquatic population, which just allegedly spent 1.5 million years specializing in semi-aquatic living could out-compete the same ancestral population that spent the same amount of time further specializing in terrestrial living defies any Darwinian explanation.

 

I looked into the article I mentioned before. It is not unscientific in nature (yes, i have reviewed papers before, and rejected some because they were not up to standard. I know the business).

they seem to base their speculations on 4 different sets of evidence: 1. comparisons of postcranial skeletons, 2. tooth enamel microwear, 3. strontium:calcium ratios, 4. isotopic evidence. You might not agree with their conclusions based on this evidence, but that doesn't mean it is unscientific. I'm not really totally convinced after reading the article (although they make some interesting analogies), but i doubt that I would be totally convinced reading articles about the other theories, because in general we just have a lack of evidence.

I find it really strange that the opinions are so polarized on this matter in this forum when there is clearly no definitive evidence for any of these theories. If you think otherwise then please endulge me and point me towards it.

Q:
and no...the theory has not been proven to be false. Some people think it is not true...it is not the same.

++Here's something to think about. When the semi-aquatic population returns to land, by what Darwinian mechanism are they able to out-compete the population that never became semi-aquatic in the first place? +++

because adaptations to the 'aquaboreal' lifestyle gave them advantages in the end.... Adaptations that are evolved for one purpose sometimes turn out to be useful for other purposes, or have multipurpose to start with. Sometime certain environments just accelerate the evolution of certain structures. It's all hard to predict, and even in hindsight it is difficult to guess which selective pressure caused which feature.

+++You will not find the AAT in any peer reviewed journals except when used for refutation+++

except that this one was in a peer reviewed journal and I found other articles supporting aqua-arboreal ideas in peer reviewed journals.
I think we settled now the question if ATT is represented in peer review articles or not. It is.

 

Much of the confusion between the orthodox and the alternative view of human evolution seems to be caused by deficient definitions of 'terrestrial' and 'aquatic'. After all, what is the difference between 'semi-terrestrial' and 'semi-aquatic'? If 'aquatic' only means 'marine', or if it means 'fully aquatic' as in sirenians (dugongs and manatees) and cetaceans (whales, porpoises, dolphins), these views are improbable in our opinion (e.g., Bender et al., 1997). And if 'terrestrial', as opposed to 'aquatic', includes 'arboreal', everybody agrees that humans display many 'terrestrial' features. No aquatic theorist doubts that many human characteristics are, at least partly, due to our arboreal inheritance, for instance, our tendency to truncal erectness, elongated limbs, mobile hands, large brain, and varied sound production (e.g., Verhaegen, 1993, 1997). Nevertheless, there can be no doubt that if 'terrestrial' only means 'savannah', this view is comparatively and physiologically impossible, since humans in almost every respect are very different from savannah-dwellers (e.g., Schmidt-Nielsen, 1979; Morgan, 1982, 1990, 1997; Verhaegen, 1991b, 1997).


characteristics of a savannah dweller

*relative independence of drinking-water and water-containing nourishment, high tolerance of dehydration and radiation heat, high diurnal body temperature and high daily temperature fluctuations, high renal concentration power, very large external ears, slender build, and running velocities of 30 miles per hour and more.
*Savannah mammals are never plantigrade like bears, eared seals or African hominoids.
*Most of them do not have dextrous hands like racoons, many otters and primates.
*They never have abundant subcutaneous fat deposits, but protect themselves from the sun with short, light-reflecting fur (or with mud coverings in elephants or rhinoceroses).
*Their vocalisations are less varied than those of dolphins, otters or primates. *They never copulate face to face like some slow branch-hangers (sloths, pottos, orang-utans), marine mammals (cetaceans, sirenians) and humans. All have an excellent sense of smell, as opposed to many marine mammals and humans.
* Most of them grow up fast and reach adulthood in two or three years, unlike hominoids, walruses, cetaceans or sirenians.
*They can sustain body temperatures of more than 40°C (Grant's gazelle can maintain 46°C for many hours) and show temperature fluctuations of more than 6° between day and night.
*Their urine concentration can be twice that of humans.
*They can bear a dehydration of 20 per cent and more, whereas in humans a dehydration of more than 10 per cent is fatal without medical intervention. *They are very conservative with salt and water (many savannah mammals, even carnivores like the fennec fox, do not need drinking-water), and never sweat ten to fifteen litres a day as humans can do in hot environments (hunting-dogs and many other savannah-dwellers do not sweat at all). (Marc Verhaegen)