Aquatic Ape Theory (evolution)

[painted wolf]

There are?
Can you provide any sources?

I've heard of monkies being fed fish, but never fishing or diving for themselves.

wa:do

[Jaiket]

Originally Posted by Tau

Why do or why don't you agree with this theory?

Most texts I've read on human evolution have dismantled it. I always thought it a pleasing theory in a way - to think of our ancestors as dooking for fish.

I have, for the record, tried to catch fish in rivers and the ocean. It appears to be impossible.

[Tau]

Originally Posted by Somkid

There are monkeys in Asia that dive for fish so, it is possible.

'Nothing is impossible, thats the beauty of science!'
So says a certain space courier business owner and world famous scientist, well known to the fans of Futurama as 'The Professor', employer of Bender, the universe's most felonius robot.

For me that just highlights the remarkable Class that is mammalia, mammals, as old as dinosaurs yet they have not forgotten they were once fish and I think probably 99.999% of mammals can swim, I have seen cows swim, they don't seem particularly well designed for swimming but they do it comfortably enough, conditions permitting.

[logician]

All land animals(vertebrates) evolved from fish, I don't think they all can swim.

[Tau]

Originally Posted by logician

All land animals(vertebrates) evolved from fish, I don't think they all can swim.

Most can, its a lot easier to list those that do compared to those that don't, but as always Logician in biology nothing is absolute....there are always exceptions.

[painted wolf]

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

[Halcyon]

I believe in certain aspects of a certain version of the AAH. I also believe in certain aspects of tha Savannah hypothesis, both have their flaws though.

I believe early hominids evolved in environments akin to today's mangrove swamps/forests, but that when the swamps dried up we moved onto the Savannah.
I believe that the AAH has the best explanation for the hair loss, although not to reduce drag but to prevent water clogging, our odd shaped noses and the various other human oddities. I believe that when we moved onto a more land based Savannah habitat the physiological changes we acquired in the swamps - long, straight legs for wading, less hair etc predisposed us to living a certain lifestyle that then shaped our bodies further into what we are today.

But I don't believe there was ever a fully aquatic hominid, only semi-aquatic like today's proboscis monkeys, swimming a bit but mostly wading.
I also accept that many of the uniquely human features have also been shaped by sexual selection.

I agree with many of PWs points, but because I believe hominids only ever partially adapted to a semi-aquatic environment, and as such would never expect pinniped-like adaptations.
I picked up on a couple of points of hers I thought odd though;

1) Fur seals, otters, taipers (most aquatic/amphibious mammals have fur)
When an animal adopts an aquatic or semi-aquatic lifestyle, fur wise it will go one of two ways, either it will become oiled and streamlined like an otter, or lose it like a hippo. So, the fact that "most" aquatic animals have fur is neither here nor there really. Plus, I personally believe in the idea that hair loss was a reaction to water clogging from constantly dipping in and out of the water rather than streamlining.

Also, this argument can be flipped back on the Savannah hypothesis too. The Savannah hypothesis suggests that we lost our hair to give a better flow of sweat across the skin, yet other Savannah primates like baboons, and fast moving animals like cheetah and gazelle have not lost their hair.

7) humans do not have 'waterproof' skin... just soak in a bath and look at the wrinkles.
Humans are very greasy, even amongst mammals, but even so if you put a dolphin in bath water it's skin would wrinkle, bath water is hardly isotonic after all.

8) Early hominids ate tough plant foods that left distinctive marks on the teeth. These show a diet high in rough foods like nuts, tubers and woody materials. Not the sort of food one finds in the water.
But it is the sort of food you'd find in a mangrove swamp, plus if you're eating bony fish and crustaceans you're also going to wear down your teeth.

9) most early hominid finds are in dry environments like savannas and such. Not aquatic environments.
Except of course that the vast majority of fossilisation occurs in water . Even Lucy was found in an area flooded between 7 million and 70 thousand years ago.

10) Upright posture has been shown to be very effective at cooling the body, in conjunction with sweating.
It's also been shown to be very bad on the spine, something that the lumbar support offered by water would avoid. Also this support would aid in its propagation within the population, and accentuation over time as a beneficial gait - also with the straightening and lengthening of the legs for wading.

11) Apes like Gibbons and Orangutans show that upright walking in the trees is also a good way of moving around. Finds like Orrorin show that walking upright predated leaving the forests. Orrorin was found in dry evergreen forest environment, not a wet one.
Yes, but it's nothing like the kind of upright stance we find in humans is it. Plus, lots of animals are capable of adopting an upright posture for extended periods, obvious ones being bears, kangaroos and monitor lizards. The fact that these animals normally walk on four legs doesn't prevent them walking on two, and if put them in a situation where the best option was to wade upright through water it's easy to imagine them adapting to such a situation over time until they do walk upright more often than four-legged.

[painted wolf]

When an animal adopts an aquatic or semi-aquatic lifestyle, fur wise it will go one of two ways, either it will become oiled and streamlined like an otter, or lose it like a hippo. So, the fact that "most" aquatic animals have fur is neither here nor there really. Plus, I personally believe in the idea that hair loss was a reaction to water clogging from constantly dipping in and out of the water rather than streamlining.
we have no good idea what the early hominids noses looked like, but evidence indicates more ape like than human like. This idea is also problamatic as ape faces are naked, so water in the nose due to hair is a non-issue.

Also, this argument can be flipped back on the Savannah hypothesis too. The Savannah hypothesis suggests that we lost our hair to give a better flow of sweat across the skin, yet other Savannah primates like baboons, and fast moving animals like cheetah and gazelle have not lost their hair.
Cheetah, baboons and gazelle are not sweat cooled.

Humans are very greasy, even amongst mammals, but even so if you put a dolphin in bath water it's skin would wrinkle, bath water is hardly isotonic after all.
then soak in a lake/ocean/swamp and see the same effect.

But it is the sort of food you'd find in a mangrove swamp, plus if you're eating bony fish and crustaceans you're also going to wear down your teeth.
fish and crustaceans leave different wear patterns... these are not seen. Chemical signatures are also not in line with marine or aquatic habitats.

Except of course that the vast majority of fossilisation occurs in water . Even Lucy was found in an area flooded between 7 million and 70 thousand years ago.
or volcanic ash... where many of the early hominids are found. Or caves... also a good spot for hominid remains... the sedimentary areas where hominids are found are river systems in savanna environments... never mangrove or other swampy landscapes.

It's also been shown to be very bad on the spine, something that the lumbar support offered by water would avoid. Also this support would aid in its propagation within the population, and accentuation over time as a beneficial gait - also with the straightening and lengthening of the legs for wading.
sorry, but this doesn't work. Bipedal movent is often seen in modern apes on the ground. It is used by gibbons and orangs to move through the trees. It is shown in Orrorin who lived in a dry forest environment. It was also indipendantly evolved in another ape on a dry woodland island.

Yes, but it's nothing like the kind of upright stance we find in humans is it. Plus, lots of animals are capable of adopting an upright posture for extended periods, obvious ones being bears, kangaroos and monitor lizards. The fact that these animals normally walk on four legs doesn't prevent them walking on two, and if put them in a situation where the best option was to wade upright through water it's easy to imagine them adapting to such a situation over time until they do walk upright more often than four-legged.
Not like we have now... but it is like the type of upright movement we would expect from the earliest hominids. Most animals put in an aquatic situation (look at the crab-eating macaques) simply swim when in the water.
There is no need for water to be a part of our upright evolution.

If early hominids were ever found in mangrove or watery environments then fine, you may have a case. But they aren't. They are found in dry savanna or open woodland environments.

wa:do

[Halcyon]

we have no good idea what the early hominids noses looked like, but evidence indicates more ape like than human like. This idea is also problamatic as ape faces are naked, so water in the nose due to hair is a non-issue.
I wasn't talking about noses, just normal body hair. If you spent a lot of time wading and swimming you'd get your fur water clogged which could lead to disease. So, you can either lose it or oil it + change it's structure to resist water.

Cheetah, baboons and gazelle are not sweat cooled.
And so it isn't necessary to lose hair to remain cool in a savannah environment.

then soak in a lake/ocean/swamp and see the same effect.
You won't though, not in the ocean or an open mangrove swamp because they're isotonically similar to human cells - unless you spend hours and hours in there in which case you could get some degradation of the upper layers of the skin, but its not the same thing as being in fresh water.


fish and crustaceans leave different wear patterns... these are not seen. Chemical signatures are also not in line with marine or aquatic habitats.
What about mangrove or boggy forest?

or volcanic ash... where many of the early hominids are found. Or caves... also a good spot for hominid remains... the sedimentary areas where hominids are found are river systems in savanna environments... never mangrove or other swampy landscapes.
So far. I don't know at what stage the semi-aquatic phase was, just that I believe there was one.


sorry, but this doesn't work. Bipedal movent is often seen in modern apes on the ground. It is used by gibbons and orangs to move through the trees. It is shown in Orrorin who lived in a dry forest environment. It was also indipendantly evolved in another ape on a dry woodland island.
Nothing like ours though, which is more like the proboscis monkey's wading posture. Gibbons and orangs use their arms for support. And perhaps it did evolve in another woodland ape, but that doesn't mean it happened that way in humans.

There is no need for water to be a part of our upright evolution.
No need, but I think it explains a lot.

If early hominids were ever found in mangrove or watery environments then fine, you may have a case. But they aren't. They are found in dry savanna or open woodland environments.
I'm willing to bet we'll find some in mangrove swamps in the future, or that our understanding of paleogeography will improve to the extent that we'll reclassify the habitats of some of those already discovered.

What's the savannah hypothesis's explanation for the shape of our nose by the way? I can't find it on the net.