Aquatic Ape Theory (evolution)

[Somkid]

Proof??? No, I just made it up for something to do. Anyway try google don't be lazy.

Proboscis monkey (Nasalis larvatus)

Proboscis monkey - The swimming star with the giant nose

Proboscis Monkey - Wikipedia, the free encyclopedia

I know there is also another much cuter monkey that swims but I can't remember the name and I'm to lazy to look it up.

[painted wolf]

ok, so before accusing me of being lazy, perhaps you should read my next responce.
I'll add it to this post, so you don't have to read to much:

Originally Posted by me

ok... so I looked into it and the Indonesian "Crab-eating" macaque does indeed do a bit of swimming in its mangrove habitat... but it doesn't dive for fish.
They will eat crabs if they can get them but mostly they pick up fallen, floating fruit.
They still spend the majority of their time in the trees or on dry land.

wa:do

Now as for research.. the proboscis monkey doesn't eat meat... it is an herbivore. So no diving for fish.
here it is on Wiki

The Proboscis Monkey also has a large belly, as a result of its diet.[citation needed] Its digestive system is divided into compartments, with bacteria that digest cellulose and neutralize toxins from certain leaves. This lets the monkey eat leaves and remain in the forest canopy. The contents of their stomach weigh about a quarter of their whole body.[4] A side-effect of this unique digestive system is that it is unable to digest ripe fruit, unlike most other simians.[citation needed] The diet consists mainly of seeds, leaves, mangrove shoots and unripened fruit.[5]

here it is from an actual biology papers: SpringerLink - Journal Article

Feeding trials were conducted with a troop of six proboscis monkeys (Nasalis larvatus) at the New York Zoological Park to quantify aspects of digestive physiology. Diets consumed comprised, on an as-fed basis, 55% browse and green produce, 11% fruit, 9% commercial primate diets, 9% root vegetables, and 16% miscellaneous items. Total feed intake averaged 12% of body mass; dry matter intake was 3%. Dry matter and plant cell wall disappearance exceeded 80%. Passage marker studies (three 6-day trials) revealed: transit time=14 hr; mean passage time=49 hr; and 5–80% retention time=52 hr. Digestion coefficients and retention times were greater than expected based on body size. These results might reflect the low fiber content of the diets fed, or alternatively, provide evidence that proboscis monkeys are efficient digesters of cell wall constituents.

here it is from Proboscis Monkey (Nasalis larvatus)

The proboscis monkey is described as being a folivore/frugivore (Yeager, 1989). Yeager (1989) found that in Tanjung Puting National Park in Indonesia, that this species utilizes 47 different plant species, of which 17 plants were consumed for their fruit, seeds, or flowers and 30 species were consumed for their leaves. The most important species used in Tanjung Puting National Park were Eugenia sp., Ganua motleyana, and Lophopetalum javanicum (Yeager, 1989). At Gunung Palung Nature Reserve, the most important plant species consumed were Mesua lepidota, Palaquium sp., Baccaurea lanceolata, Barringtonia racemosa, and Salacia macrophylla (Ruhiyat, 1986). Also at Gunung Palung Nature Reserve the most frequent tree species visited for fruit was Syzigium borneense and Dialium indicum (Ruhiyat, 1986). At Samunsam Wildlife Sanctuary it was found the majority of food consumed was fruits or seeds and young leaves were next most important food item (Bennett and Sebastian, 1988). Fruits eaten tend to be of the dry and bitter-tasting type (Bennett and Sebastian, 1988). In Sarawak it was found that the food item consumed representing the most number of species were leaves (Salter et al., 1985). Leaves consumed tend to have high levels of protein and low levels of digestion inhibitors (fiber) (Yeager et al., 1997). The leaves consumed tend to be high in levels of phosphorus and potassium (Yeager et al., 1997). Seeds of fruits tend to be more important than the flesh itself as a food source for the proboscis monkey (Yeager, 1989). At Samunsam Wildlife Sanctuary this species prefers the seeds of the families Leguminosae and Myristicaceae (Bennett and Sebastian, 1988). This species feeds predominately on the seeds of the following species: Eugenia sp., Ganua motleyana, Lophopetalum javanicum (Yeager, 1989). An effect of seed predation by this species is that it assists in maintaining vegetational diversity in the areas where it lives (Yeager, 1989). Invertebrates are also consumed, examples of which are mosquitos, caterpillars, and insect larvae (Yeager, 1989). In Tanjung Puting National Park it was found that this species tended to be more frugivorous from January to May and more folivorous from June through December (Yeager, 1989). This species also eats shoots of mangrove trees and flowers. The proboscis monkey prefers to consume immature leaves over older ones. It was found that in Tanjung Puting National Park that the diversity of plant species used for food increased when the trees that had young leaves decreased (Yeager, 1989). In the Lower Kinabatangan, Sabah, it was found that the food resources for this species are unevenly distributed and highly clumped, and it was suggested that this influences the low level of aggression between groups and group ranges that overlap (Boonratana, 1994). This species predominately feeds in the morning and in the evening (Macdonald, 1982). In Sarawak it was found that this species feeds from 1 meter above the ground to the mid to upper canopy trees (Salter et al., 1985). When feeding, lion-tailed macaques, Macaca silenus, and orangutans, Pongo pygmaeus, will displace the proboscis monkey at feeding sites (Yeager, 1989).

research.
the ability to swim and fishing behavior are very different things. You claimed the monkeys dive for fish to eat. I have not now nor ever in my research found information to this effect.

wa:do

[painted wolf]

here is info on your 'cuter monkey' Macaca fascicularis "long-tailed or crab-eating macaque"

ADW: Macaca fascicularis: Information

Long-tailed macaques are omnivores, and exploit many different food types, reflecting the diversity of habitats they can utilize. The average length of feeding bouts is 18.3 minutes. There may be on average of twenty bouts per day. They eat a wide variety of foods such as fruits, crabs, flowers, insects, leaves, fungi, grasses, and clay. Clay may be eaten for the potassium found in it, although the potassium levels in the clay are low. However, 96% of the feeding time per day is spent eating fruit. Some limited observations suggest that long-tailed macaques select fruit based on ripeness, which is based on color.

from: Crab-eating Macaque (Macaca fascicularis)

The crab-eating macaque is a frugivorous species, but will also eat leaves, insects, grasses, seeds, flowers, buds, shoots, gum, sap, and bark. This species will also raid crops and eat the food such as rice and taro plants. It will also forage for plant species located near water (Richard, 1985). The average group size for the crab-eating macaque is 30 individuals. This species is mostly arboreal, spending much of its time in the forest canopy, but it occasionally comes down to the ground. This is a diurnal species.

again.. primarily herbivores.

from: issg Database: Ecology ofMacaca fascicularis

Nutrition
Herbivorous: Fruit and seeds make up 60 - 90% of the dietry intake of macaques. They will also eat leaves, flowers, roots and bark.
Carnivorous: They prey on vertebrates (including bird chicks and nesting female birds) and invertebrates.
Omnivorous: In Mauritius they have been recorded eating bird eggs.

No mention of fish.

wa:do

[Halcyon]

so we loose our body hair... and it gets greasy? It either one or the other.
I believe you may have misread me, this is exactly what I said.

Our hair is actually more like young apes.. it a neoteny trait.
A neoteny trait? Despite the fact that adult humans develop more hair over time?

And so it isn't necessary to lose hair to remain cool in a savannah environment.
even less for a mangrove... but seriously our sweat cooling is far more efficent than anything else out on the savanna.
I imagine it is, but what was the selective pressure?
Think about it, our pre-hominid ancestors were as hairy as baboons right? They used the same methods to cool down that modern hairy mammals use, right? So what triggered the hair loss?
I can't imagine a reason for one species amongst all the hairy mammals inhabiting the plains of Africa to lose its hair as a coolant system, while the rest retain it and do just fine. There needs to be a trigger, which I believe was most likely water.
Water logged fur is cumbersome and a disease risk, so either lose it or oil it.

Which again is why a human hunter can literally run down a meal by inducing the animal into heat shock.
You've said this before, but I can't off the top of my head think of any group of humans who hunt by chasing down prey faster than they are, rather than using the ambush and trapping methods that the vast, vast majority of humans do. Maybe you have an exception to the rule in mind (which I'd be interested in learning about if you have a link) but even then we both know that exceptions do not prove the rule.

if we were aquatic enough for it to determine our evolution it would be hours and hours. We are not built for hours and hours of aquatic time. We are very well adapted for long exposure to the sun and heat of a savanna environment.
I never said we were well adapted if you go back and read my original posts, I said I think we were only ever partially adapted to a semi-aquatic lifestyle.

What about mangrove or boggy forest?
Nope sorry.
Would you mind expanding, because just from this it looks like you're trying to tell me that there are no edible nuts, seeds, roots or leaves in a mangrove forest - which I can't believe is what you actually meant.

So far. I don't know at what stage the semi-aquatic phase was, just that I believe there was one.
Faith is not evidence
No, but then I imagine Huxley had similar comments made towards him after his theory of therapod to bird evolution. But just like the recent discovery of feathered therapods adds weight to his theory, I have confidence (not faith) that we will discover direct evidence of a semi-aquatic phase of hominid evolution.


Wrong. Our posture is more like other apes than it is any monkey. Proboscis monkeys spend much of their time in the trees eating leaves. Walking on the branches on all fours.
I have to disagree, a proboscis monkey walks with its back straight, legs straight and head up when wading, just as we do when walking normally. Apes walk with bent legs (unless supported using their arms) and a curved spine, heads lent forward.

On the ground they moved like us. This mode of walking is more energy saving when covering the distances between groups of trees than knuckle-walking.
Humans were built to run, not wade.
Again, I would have to disagree and say that humans are perfectly suited to both. In my case I happen to believe that a lifestyle of wading predisposed us to a latter evolution of bipedal running.

If its not needed than parsimony says its out. No need means just that not needed, it explains nothing.
Not needed in that I can see that most aspects of human evolution can be explained by other theories as well, but if we're talking parsimony then I would have to suggest that it is far more parsimonious for hominid characteristics to be explained using a single factor - the effect of water - over many different and largely unrelated alternative explanations.

Finding a mangrove swamp in the middle of Africa would be quite a thing.
It would indeed, but who mentioned the middle of Africa?


What's the savannah hypothesis's explanation for the shape of our nose by the way? I can't find it on the net.
genetic drift. That accounts for the shape of our skull as well.
Genetic drift? Sorry, I don't buy that. I don't think it likely that we can go from open-nosed to hooded nostrils without selective pressure involved, I can't see chance allelic drift accounting for it.

Having your nostrils point in the human fashion and being aquatic is frankly stupid. No aquatic animal has nostrils that point downward, you would drown. And humans often do.
Again, I think you're mistaken. Go to a swimming pool and descend vertically into the water, as if wading from shallow to deeper water, and see what happens.
Air gets trapped in the nostrils forming a natural air lock preventing water rushing in. The effect is even more obvious if you're dropped from a height (like a tree branch). Try doing that with a gorilla or chimp with an flat, open nostriled nose and see what happens.

[painted wolf]

A neoteny trait? Despite the fact that adult humans develop more hair over time?
yup. neoteny didn't get rid of the trait... just the nature of the finished product. Like changing fur types in "domestic fox" vs. wild ones. Or any other neotenus trait.

I imagine it is, but what was the selective pressure?
cooling and likely sexual selection.
Think about it, our pre-hominid ancestors were as hairy as baboons right?
No hairy as chimps... who are much less hairy than baboons. We are not baboons, we are apes.
we have the same amount of hair as a chimp, just lighter. We are far from hairless.
They used the same methods to cool down that modern hairy mammals use, right?
No we are sweat cooled... chimps sweat too, but not nearly as much. Other animals pant.

So what triggered the hair loss?
cooling power of sweat likely augmented by sexual selection.
I can't imagine a reason for one species amongst all the hairy mammals inhabiting the plains of Africa to lose its hair as a coolant system, while the rest retain it and do just fine. There needs to be a trigger, which I believe was most likely water.
mutation and natural selection work just fine. Why sweat in the water?
Water logged fur is cumbersome and a disease risk, so either lose it or oil it.
your aquatic monkey does neither.

You've said this before, but I can't off the top of my head think of any group of humans who hunt by chasing down prey faster than they are, rather than using the ambush and trapping methods that the vast, vast majority of humans do. Maybe you have an exception to the rule in mind (which I'd be interested in learning about if you have a link) but even then we both know that exceptions do not prove the rule.
http://en.wikipedia.org/wiki/Persistence_hunting
Persistence hunting in modern hunter-gatherers

I never said we were well adapted if you go back and read my original posts, I said I think we were only ever partially adapted to a semi-aquatic lifestyle.
Then why continue to walk when not in the water? No semi-aquatic animal walks bipedally as a habit. Not even the wading monkeys.
No we needed a full time need for upright movement, not a part time one.

Would you mind expanding, because just from this it looks like you're trying to tell me that there are no edible nuts, seeds, roots or leaves in a mangrove forest - which I can't believe is what you actually meant.
There is no chemical signature of a brackish or aquatic diet.

No, but then I imagine Huxley had similar comments made towards him after his theory of therapod to bird evolution. But just like the recent discovery of feathered therapods adds weight to his theory, I have confidence (not faith) that we will discover direct evidence of a semi-aquatic phase of hominid evolution.
Huxley based his theory on solid evidence based on strong morphology. AAT doesn't do this. Its all tenuous and often misrepresented links at best.

I have to disagree, a proboscis monkey walks with its back straight, legs straight and head up when wading, just as we do when walking normally. Apes walk with bent legs (unless supported using their arms) and a curved spine, heads lent forward.
Not from the footage I've seen, they wade leaned forward. They walk on all fours when on dry land. (to support their massive stomachs)

Again, I would have to disagree and say that humans are perfectly suited to both. In my case I happen to believe that a lifestyle of wading predisposed us to a latter evolution of bipedal running.
Why would we continue to walk upright out of the water? No other animal does this.
Branch walking is far more likely as it preadapts us support out full weight on the ground. Plus the fossils are more in support of this. Orrorin for example.

Not needed in that I can see that most aspects of human evolution can be explained by other theories as well, but if we're talking parsimony then I would have to suggest that it is far more parsimonious for hominid characteristics to be explained using a single factor - the effect of water - over many different and largely unrelated alternative explanations.
aquatic is far from parsimonious. We need to leave the trees and adapt to the water... we need to leave the water and adapt to the open woodland... we need to adapt to the open savanna and so on.

With the upright branch walking we simply need to go from the branches to the ground and then from the ground to more open forest/savanna.

It would indeed, but who mentioned the middle of Africa?
Early hominids have yet to be found outside this area.

Genetic drift? Sorry, I don't buy that. I don't think it likely that we can go from open-nosed to hooded nostrils without selective pressure involved, I can't see chance allelic drift accounting for it.
you need to study allelic drift more. Humans have undergone several severe bottlenecking effects. There is plenty of time and loss of genetic diveristy to account for this.
It accounts for the shapes of the nose we have already. Wide, hooked, narrow, button... its all genetic drift. Why not the overall shape?
Evidence indicates that genetic drift accounts for the overall shape of our heads... why not the nose?

Again, I think you're mistaken. Go to a swimming pool and descend vertically into the water, as if wading from shallow to deeper water, and see what happens.
I float to much to walk like that. My head tilts and I get a nasal passage full of water. Even when standing still because of the waves on one of our larger lakes.
Air gets trapped in the nostrils forming a natural air lock preventing water rushing in. The effect is even more obvious if you're dropped from a height (like a tree branch). Try doing that with a gorilla or chimp with an flat, open nostriled nose and see what happens.
I have plenty enough experience with near drowning thanks.
It would be far more likely we would have adapted with closeable nostrils rather than the large open ones we have. Even chimps can shut their nostrils better than we can.
Hardly a logical adaptation.

wa:do

[Halcyon]

I see all the things you suggest as being indicative of entirely land-based evolution as latter adaptations to savannah life after a semi-aquatic one. You said yourself that all the fossil evidence we have is from the savannah, I think eventually we'll find the remains of a population of semi-aquatic early hominids in coastal regions.

[painted wolf]

We have found "modern human" fossil remains in coastal areas... but no early hominids.

We have several early hominids from dry forest/savanna environments.
You simply can't discount Orrorin. Dated to about the same time as the genetic evidence of the split between chimps ancestors and hominids, it is already a biped.
It also shows adaptations for branch walking.

It would take a pretty specatular find to supercede Orrorin.

wa:do

[Halcyon]

Originally Posted by painted wolf

It would take a pretty specatular find to supercede Orrorin.

And I think we'll find it, in time.

[painted wolf]

until we do, I'll stick with the theory with the evidence.

wa:do