A New Twist on the Aquatic Ape Theory

[DavidMcC]

I entirely agree it would have made sense for early homo to prefer to stay around permanent lakes, gwolf.

[JeffLee]

Wherever did you get THAT idea? "Skin temperature" (approx 23C) is not the same as "body temperature," except around the anus and sometimes the auxilia.

umm. that's room temperature.

there is a difference. ^^

You have provided me with another possible argument in favor of the amphibious ape. I note that in humans the anus is deep between the buttocks, unlike the other primates, where it sits closer to the outside world adjacent to the ischial callouses. Why would it be so far retracted, especially since this makes fecal soiling much more of a problem for humans than for other mammals? I will speculate that the buttocks insulate the anus when the body is immersed, thus making it easier to maintain rectal temperature properly.

question: if our anus apparently needed all this insulation, how did our external testes manage? since internal testes appear to be stock&trade of marine mammals...

Does this mean you are certain that DHA automatically enlarges the brain?

When under pressure for "bigger brains"? it appears so. unless you can find fault in largy's source or are suggesting that there was no pressure for brain growth pre late erectus then i can't see much alternative.

]As a result of these exchanges, I suggest water as a place to flee only from lions, which is not an insignificant problem.

i imagine prides could lay waste to a tribe, but single cats shouldn't be much of a problem.

so the next issue would be when group living evolved in the larger cats.
this article seems to touch on it, alas i cannot access it.

in any event i have my doubts that it was significant enough for apes to altogether change environments. trees provided ample protection for their precursors, why should it be much different for the early hominins. Lucy was, after all, [anatomically] a decent climber.

When I checked references on freshwater sharks I discovered nothing claiming that they have ever inhabited the Great Rift Valley in Africa. So they weren't a problem.

alright then.

I'm looking through my copy of Jared Diamond's book, but since I didn't annotate it, I think it will take awhile to find.

I'll flip through the index again myself.

It does? Each of the exchanges between terrestrial and amphibious ape advocates has been a trade-off. To test the hairy aquatic ape problems, we'd need to dress somebody up in a hair suit and have them swim off against somebody without one. The limits to the diving reflex don't mean much in rift lake waters. The problems with human skin not "designed" for immersion are moot if the hominid doesn't remain immersed for more than two hours. The problems with insulating fat distribution mean little if the water is close to skin temperature. Salinity varies from lake to lake, so the amphibious ape theory stands as long our ape avoids the most saline or "soda-y" lakes.

"Each of the exchanges between terrestrial and amphibious ape advocates has been a trade-off."
"so the amphibious ape theory stands"

am i alone in seeing a problem there?

btw: do you think that 2 hours water time is enough of an environmental pressure to evolve a whole new method of locomotion?

]From what I've heard and read of the years, we may indeed digest meat in general better than the pongids but digestion of meats is most efficient with fish.

this doesn't explain why we are better at eating red eats if they have been eating it longer...

This data seems to make it easier rather than harder for hominids to become lake-amphibious.

hmph. it appears I've been caught with my pants down. with lake turkanas average temp of 29C plus the slight warming it is indeed 'very close to skin temperature'.

darn, that's a real kick in the teeth.

we can probably now drop the above anus/testes temperature line as irrelevant.

I already talked about the lions, although this may not be necessary to prove the amphibious ape hypothesis. Merely feeding on mollusks and later fish would do it.

i must have missed it then. I'll await you DHA response before touching on feeding.

We need water because we sweat, not in spite of it. Plus, hominids are bigger than wolves, exponentially multiplying their heat disposal problems.

which is why they got taller, thinner and longer arms?

I'm also interested getting falsifiable data. Would you provide me with a research grant to help me pursue this?

i asked for a structured hypothesis, not data. ^^ besides, you could always ask national geographic. they've funded non scientists in human origins research before.

[quote]
I can't help you with the hobbits unfortunately. Where do they fit in between h. habilis and h. sapiens?[quote="JeffLee"]
http://en.wikipedia.org/wiki/Homo_floresiensis

[DavidMcC]

This article in answers.com makes an interesting point for those who still think that the savanna alone made humans:

A climatic trigger for hominin origins is often invoked. A period of late Miocene aridity in Africa is thought to have eliminated forests and caused the spread of extensive open-country grasslands, and thus created selection pressures for the origins of terrestrial bipedal hominins. However, Sahelanthropus, Orrorin, and later hominins that are well known postcranially are found in environmental mosaics that include forested areas. The origins of terrestrial bipedal locomotion, therefore, cannot be simply linked to the disappearance of forest and the spread of grasslands.

[hecate]

This article in answers.com makes an interesting point for those who still think that the savanna alone made humans:

A climatic trigger for hominin origins is often invoked. A period of late Miocene aridity in Africa is thought to have eliminated forests and caused the spread of extensive open-country grasslands, and thus created selection pressures for the origins of terrestrial bipedal hominins. However, Sahelanthropus, Orrorin, and later hominins that are well known postcranially are found in environmental mosaics that include forested areas. The origins of terrestrial bipedal locomotion, therefore, cannot be simply linked to the disappearance of forest and the spread of grasslands.

This article leads me to conclude it might be even more complicated.

Although perhaps controversial, it is important that when considering such a unique adaptation as bipedalism, we do not allow that uniqueness to imply that there was ever only one successful mode of bipedalism in our hominin ancestry. In light of the richness of recent findings in the hominin fossil record, it is important to ask the question of whether the evolution of bipedalism was a more complex affair than has previously been suggested.

[JeffLee]

Origins Reconsidered/L'argenton says:
thats a fair comment

[generic Panda related username] says:
the AAH guys are going to drool over that 5 mya line

Origins Reconsidered/L'argenton says:
definitely


Anyway... you know that DHA paper that largy introduced? well, i managed to contact one of the authors [over a little quibble about the human fossil record being 'linear' or not] and he said something i think you AAHers are probably going to enjoy.

However the inhabitants of the Olduvai Gorge were living beside a lake and river. Much of the other inland fossils were beside the Rift Valley Lakes and the latest evidence of Klasies and Eritrea provide incontrovertible evidence of extensive exploitation of the marine food chain (0.125 mya). They certainly were not killing buffalos as the migrated around the coast lines to populate the planet!

It is the discovery of these large brained hominids now recognised as human that led people to conclude the last phase was a major jump. My own opinion was that it had been going on for the best part of 5 My so that the coastal ape was able to maintain the high brain body weight ratio as they had as small mammals (squirrel 2.5% modern Hs 1,9%)

and that is Dr. Michael A. Crawford, PhD, CBiol, FIBiol, FRCPath in an email sent to myself at May 13, 2007 6:15:28 PM.

[gwolf]

Yipes, JeffLee, that was dramatic indeed, actually far more than I was hoping for.

I think I'll take a long soak now, and wait for my skin to fall off.


George Wolf

[Aaron SF]

Thanks for posting this george, this is by far one of my favorite threads and incidently one of my favorite hypothesis for the evolution of modern human traits.

I have to admit that it's my favorite for purely sentimental reasons though. I don't think it has quite enough evidence yet, but I look forward to reading more about it.

[gwolf]

Thanks for posting this george, this is by far one of my favorite threads and incidently one of my favorite hypothesis for the evolution of modern human traits.

I have to admit that it's my favorite for purely sentimental reasons though. I don't think it has quite enough evidence yet, but I look forward to reading more about it.

What interests me is that some people with technical knowledge have come up with real evidence for the amphibious ape that I knew nothing about. That makes me very happy -- unless it gets refuted! Even more important to me is that this thread has stayed at a respectful level. That is such a relief from other discussions on other subjects I've been part of over the years.

George Wolf

[Largenton]

Just to be a bit pedantic, the research doesn't actually state that we were aquatic. In fact, it only states that we used the coast around us to gather food, its not stating that we were. I know I'm being pedantic, however, I'm merely trying to be safe, you stating that it is for AAH is stretching it a little on the optimistic side. Anyway, I'm going to read Jeff's argument and try and give my opinion on it in the next few days.

[gwolf]

Just to be a bit pedantic, the research doesn't actually state that we were aquatic. In fact, it only states that we used the coast around us to gather food, its not stating that we were. I know I'm being pedantic, however, I'm merely trying to be safe, you stating that it is for AAH is stretching it a little on the optimistic side. Anyway, I'm going to read Jeff's argument and try and give my opinion on it in the next few days.

Don't worry, I'm not making a declaration of either victory or defeat. As previously stated, my search is for something falsifiable; if X is true then hominids were amphibious; if Y is true then hominids were always terrestrial. Hopefully, we won't find BOTH X and Y to be true!

As stated earlier in the discussion, I have modified my stance to favor an amphibious ape rather than an aquatic one; a creature that freely moved back and forth between lake and land. Unlike an aquatic creature, it didn't sleep in the lake (unless you believe Monty Python) nor get anymore than half its food from there. The adaptations for this life include a streamlined shape, attraction to streamlined mates, ability (like the seals) to quickly "catch on" to swimming as a juvenile, bare skin to cut the resistance to water and to take better advantage of the nearly skin temperature Rift Lakes, a skin color to camouflage the hominid in the water, speech rather than gesture language, enhanced ability to learn fast hand movements to catch the fish, secretions that attract fish (based on anecdotes and personal experience only), sensitive hands and feet to forage underwater for mollusks and arthropods, the ability to throw and catch as a quick way to transport food to others in the band on shore, an ability to digest fish more easily than mammalian meat, a retracted anus and vagina to maintain them at body temperature (as opposed to skin temperature), tears to reduce the hardness of rift lake water, and finally, a preference for skin temperature water and forested surroundings. I further propose that these are features of modern h. sapiens and people still show these adaptations.

I'd like to add the modified diving reflex and a sometimes demonstrated ability for deep diving, but I feel that I'd need more time to develop that.


George Wolf

[anthrosciguy]

Hi, I'm Jim Moore and have appeared in this forum before on this subject. I've been studying the subject for a long time now and have the Aquatic Ape Theory: Sink or Swim? web site mentioned here. Here's some observations and corrections to non-factual claims in this thread:

Streamlined shape: NOT. Plus early hominids had virtually the same bodily dimensions as bonobos, and little different from common chimps.

Diving reflex: found in all animals. Stronger in diving animals, and humans are at the "terrestrial" end of the scale.

Webbing between fingers: rare but sometimes seen, just as it is in siamangs and gorillas.

Swimming efficiency for humans is terrible; most of competitive swimming coaching is
how to decrease the naturally poor efficiency of human swimming. If human hair patterns are due to slection for swimming, why is it that the one thing competitive swimmers want when they race is what we don't have -- they either shave their hair or use body suits which mimic the effects of hair, or dermal ridges as seen in dolphins.

Humans use lots of gestures in communicating, as well as sounds, just like their relatives do. No, they don't talk, as we define talking, but then neither do any aquatic animals.

Tears are not a regulated way to get rid of salt and other minerals (neither is sweat). All mammals use their kidneys for this -- every single one. Tears are not even hypertonic for the (unspecified) minerals found in water and cannot do what AAT/H proponents claim for them. Tears are, however, strongly hypertonic in regard to potassium and that does indicate what environment we developed in. That environment is terrestrial, not aquatic. (The salt glands of terrestrial birds and reptiles are specialized for excreting potassium.)

Crocs: crocs are not usually seen before they attack, so strike that fantasy method of defense. The notion of hominids killing crocs (other than infants) in the way gwolf suggests is nonsense. For one thing, we find that during croc attacks now, with much better weapons, spears, rocks, and clubs are ineffective; crocs basically ignore them. And this doesn't take into account that crocs are often found in great numbers. The claim also ignores that large cats can and do effectively chase their prey into water where the bounding moves of the cat offer greater mobility than the running or (very) slow swimming speeds of hominids -- this, BTW, is not uncommonly seen on nature shows, so even watching TV should have shown the writer the error in the claim.

Mating face to face, as done also by orangs, black-handed spider monkeys, and occasionally in woolly spider monkeys and gorillas, and among aquatic mammals done by very few, almost all fully aquatic for tens of millions of years.

"the opinion seems to be that an aquatic or semi-aquatic environment seems to preserve more fossils than a jungle environment. Thus a plethora of hominid fossils indicates a semi-aquatic environment and a paucity of pongid fossils indicates a jungle habitat..."

The study of taphonomy is apropos to the AAT/H, but we do not have anything like a "plethora of hominid fossils". Suid (fossil pigs of various kinds) are something we do have a plethora of, as we do of many shoreside animals. The relatively few hominid fossils indicates they weren't typically found in the easy to fossilise environments like the shoreside.

"In fact on the savanna, humans are still ambush predators, using weapons (like spears, arrows and guns) to compensate for the lack of speed."

Actually, groups in open country seem to rely more on stalking, although they also use chase (persistence hunting). Our sweat glands help here; if you start at the hottest time of day in a very hot period of the year (as such chases do) we can run for long periods of time at a speed slower than the speed of the prey. This wouldn't work except that our eccrine sweat glands can keep going and going, cooling us, while the aprocrine sweat glands of the prey work quite nicely for about 20 minutes, after which they need to be recharged. Persistence hunting capitalizes on this, because the prey gets out front, but then has to rest or grow more and more tired due to overheating. This works well... for the humans.

JimC says: "Also, humans have vastly better abilities at throwing than chimps..."

Average human vs. average chimp? Not from what I've read. We can certainly get really good, but then what highly trained atheletes can do is not what's at issue. Chimps (and other primates) are quite good at throwing, strong and pretty accurate.

Fish being considered better than many other meats is due to our present circumstances where one can (if you're not in poverty) typically get as much meat as you want, as well as fat, salt, and other useful items that are problematic in large amounts. In earlier times these things were hard to get, virtually impossible to get too much of, and that's why we have appetites for these things. Now that we can get as much as we want these appetites are a problem, but before we could get as much as we wanted those appetites were the solution, making us work to get these hard to get food items.

gwolf then picks up an old Morgan tack: claiming that we should resemble distantly related mammals more than our close relatives (for instance, patas monkeys, which cool via eccrine sweat glands as we do -- and which live in open country). This is ignoring phylogeny, the central tenet of evolution, which is a very odd thing to do.

"...impossible before the invention of highly portable water-carrying tools. For this reason, I suggest that evaporant cooling could never have evolved in an arid climate. Otherwise, other creatures besides h. sapiens would probably have discovered it first."

A twofer from gwolf: first assuming that his ancestors weren't as smart as chimps, which in arid regions dig for and carry water-filled tubers (note: I'm sure MY ancestors were as smart as chimps, or close to it.) then ignoring that other creatures (other primates, in fact) have "discovered it" as well as assuming that creatures can ignore phylogeny as he does. (They can't; you shouldn't; don't do it.)

DHA is available directly or indirectly in terrestrial sources. Other required nutrients are found more easily in non-shoreline diets than shoreline, according to actual studies. You don't need all that much DHA, and the idea that DHA somehow makes your brain big is crazy talk. Now here the researchers Crawford, Cunnane et al. take a wild leap from the data. They seem to be good nutritionists but know little about evolution and have made little discernable attempt to learn. They claim, and others foolishly follow them on this, that getting more DHA makes your brain big, but if this were true we'd see fish-eating species all being smarter than they are; it turns out only a very few are relatively smart (say as smart as your average woodland dwelling primate).

Interesting email from Michael Crawford; I see this is the second time I know of that he's used hunting cape buffalo, even now considered one of the most dangerous animals to hunt even with high powered rifles, as something he'd expect a terrestrial hominid to do. Frankly, that's either dishonest argumentation or simply delusional.

[rationalrevolution]

Where along the time line of human evolution is your aquatic ape? do we have any fossils suggesting an aquatic lifestyle and/or diet related to this time line? what prompted these early apes to descend from the treetops and begin to fish? What prompted them to leave their aquatic habitat and high mountain regions for the savannah? what prompted the shift from a fish diet to larger game? I can't imagine the shift from a passive predator to open area hunter/scavenger to have been particular advantageous. do you suggest that the pressure could have been drops in lake levels? do we have corresponding evidence of these lake fluctuations? i imagine it would have to be on the extreme end as a simple retreat of the water line could be easily followed. how do chimps factor into all of this? would it not be more parsimonious to explain the evolution of bipedalism with the opening up of the African savannah as bipedalistic motion is more efficient then a knuckle walk on open terrain.

While the story in this OP isn't really relevant, there is a lot more to the aquatic ape theory that can't be so easily dismissed.

While aquatic may be over doing, I think that perhaps a swampy ape theory is much better.

Check out this wading gorilla:



There is no evidence at all to suggest that walking upright would be the result of savanna living anyway, or even that early people could survive on the savanna. That proto-humans would have gotten their start around lakes or rivers is much more plausible.

http://www.riverapes.com/AAH/AATheories ... lking2.htm

I'm certainly not sold on it, but I wouldn't rule it out either.

http://en.wikipedia.org/wiki/Aquatic_ape_hypothesis

[Largenton]

"In fact on the savanna, humans are still ambush predators, using weapons (like spears, arrows and guns) to compensate for the lack of speed."

Yes but that doesn't mean we evolved on the Savannah. After all, we would have to have those weapons in the first place right? And doesn't Crawford state in his example that:

A study of savanna and other African species show that as they evolved larger and larger bodies, the relative size of the brain diminished logarithmically with increase in body weight (1,4). A cebus monkey of 0.9 kg body weight has 2.3% of its body weight as brain, a 60 kg chimpanzee 0.5%. The larger gorilla at 110 kg has only 0.25% brain which is physically smaller than the chimpanzee’s brain. At the extreme, the one ton rhinoceros has <0.1% with its brain weighing only 350g. It reaches that massive one ton body weight at four years of age.

So unlike normal Savannah dwelling animals, somehow we got intelligent?

Fish being considered better than many other meats is due to our present circumstances where one can (if you're not in poverty) typically get as much meat as you want, as well as fat, salt, and other useful items that are problematic in large amounts. In earlier times these things were hard to get, virtually impossible to get too much of, and that's why we have appetites for these things. Now that we can get as much as we want these appetites are a problem, but before we could get as much as we wanted those appetites were the solution, making us work to get these hard to get food items.

Ummm, no. Fish is considered better because it is healthier for us.

If we now examine the contemporary evidence on cardiovascular disease we find that land
based animal fats have been causally linked to heart disease as revealed by the Seven
Countries study of the 1950s and even earlier

Whilst.....

Worldwide diets and cardiovascular risk factors show that marine fats, especially DHA, are cardioprotective

So we are stating that fish is better for your body here. Also Crawford made an interesting remark that:

It is of interest that the Turkana have the highest mitochondrial DNA diversity of any ethnic group. In fact 36 Turkana people have a higher diversity than the world-wide population database. The simplest interpretation is that humans date back to the East African Rift Valley

So its not just, we've got the most fossils here so it must be here, it is also the MitDNA that is helping prove these ideas by stating that the highest diversity is found at Lake Turkana.

DHA is available directly or indirectly in terrestrial sources. Other required nutrients are found more easily in non-shoreline diets than shoreline, according to actual studies. You don't need all that much DHA, and the idea that DHA somehow makes your brain big is crazy talk.

Why, you can't just say, "crazy talk"? I can definitely say that people have it prescribed to increase coherency. I used to take a form of DHA since I have a form of dyslexia and I could definitely tell that the DHA helped. Anyway, the argument was that DHA helped development and brain structure. Since you are claiming they are nutritional biochemists, shouldn't they be able to recognise the reasons why fish is good for you. We might not need that much DHA *now* however, what about the evolving brain structure of the other hominids? After all, I bet their EQ1 went up a lot.

They claim, and others foolishly follow them on this, that getting more DHA makes your brain big, but if this were true we'd see fish-eating species all being smarter than they are; it turns out only a very few are relatively smart (say as smart as your average woodland dwelling primate).

Which could argue for another evolutionary pressure occurring? I think we covered this earlier. Since we are social animals, I think our combined evolution of the society and the language which may have been caused by the bigger brains, could have created this rather than other animals. So perhaps it is the fact we are social animals which helped the evolution more than anything else. Environmental determinism isn't always something I like to argue for to be honest.

[DavidMcC]

Swimming efficiency for humans is terrible; most of competitive swimming coaching is
how to decrease the naturally poor efficiency of human swimming. If human hair patterns are due to slection for swimming, why is it that the one thing competitive swimmers want when they race is what we don't have -- they either shave their hair or use body suits which mimic the effects of hair, or dermal ridges as seen in dolphins.

It may be "terrible" w/r to say, dolphins, but humans never got to be fully aquatic, obviously. The point is that hair loss (except on the head, where it had other uses) w/r to the common ancestor does improve swimming efficiency, as you implicitly acknowledge with your remarks about instructors.
Maybe hair loss was the "quick and easy" evolutionary solution to improved swimming efficiency. Full shape streamlining would obviously take much longer.

[gwolf]

Hi, I'm Jim Moore and have appeared in this forum before on this subject. I've been studying the subject for a long time now and have the Aquatic Ape Theory: Sink or Swim? web site mentioned here. Here's some observations and corrections to non-factual claims in this thread:

Welcome anthrosciguy. We need the new blood.

Now, I would like to repeat something that I said in past quotes that you wouldn't be able to tell from the forum title. I am an advocate of an amphibious rather than an aquatic ape. I see an animal that enters the water to frolic forage or fish, but not much of anything else – except sex perhaps.

Streamlined shape: NOT. Plus early hominids had virtually the same bodily dimensions as bonobos, and little different from common chimps.

Have you got a study saying how modern human swimming efficiency is supposed to be less than or no better than the other apes? Can they swim? How well do they swim? I'm more interested in this than in comparing humans to other amphibious mammals because h. sapiens is a very new species. It is in effect a transitional form, not fully adapted to amphibious life. I’d predict it swims better than other apes, but not as well at all as other amphibious tetrapods.

Further, my advocacy is that modern h. sapiens is the version most fully amphibious, although I admit to speculating in earlier posts that perhaps it goes back much further. I think we humans have an attraction for grace and streamlining that wasn't all that well understood until people began building scientifically streamlined vehicles, mostly in the last 120 years. When I'm at an airshow, those around me repeatedly describe certain subsonic aircraft as "beautiful," in a way that they don't apply to anything except members of the opposite sex. Why subsonic? The rules for shockwave control change drastically above the speed of sound, and I don't know of any living being capable of supersonic performance in any medium. Therefore, no possible evolutionary need for attraction to such shapes. People tend to be good judges, too as the carefully streamlined aircraft they refer to seem to be those most capable of high subsonic speeds.

Diving reflex: found in all animals. Stronger in diving animals, and humans are at the "terrestrial" end of the scale.

Please read my reply further back in the list on this. As far as I'm concerned, humans have the right diving reflex for an amphibious animal in skin temperature water, where there would be no excessive heat loss nor gain. I'm now looking up information about voluntary breath holding.

Webbing between fingers: rare but sometimes seen, just as it is in siamangs and gorillas.

Whether by direct evolution or by exaption, the extra palm size adds to both grip and a slightly better propeller blade.

Swimming efficiency for humans is terrible; most of competitive swimming coaching is
how to decrease the naturally poor efficiency of human swimming. If human hair patterns are due to slection for swimming, why is it that the one thing competitive swimmers want when they race is what we don't have -- they either shave their hair or use body suits which mimic the effects of hair, or dermal ridges as seen in dolphins.

We have far less hair than do other apes already. Others on this list have pointed out that ape hair causes more drag in water than that of other mammals. Male pattern baldness decreases hair on a leading edge that most aeronautical engineers would want as smooth as possible. Conversely, beard hair would tend to smooth the neck's natural drag cavity. Pubic hair might do the same for the genitalia.

Humans use lots of gestures in communicating, as well as sounds, just like their relatives do. No, they don't talk, as we define talking, but then neither do any aquatic animals.

I continually read that we have little understanding of aquatic mammals' vocalizations, so I think the jury is still out on how much communicating they do. We have great problems understanding their context -- much as is the problem with Etruscan words and Linear A script. Unlike the other apes, humans can communicate without any gestures at all if the situation warrants. Otherwise shouted and telephone conversation would be entirely futile. We wouldn't write letters and we certainly couldn't post to these forums!

Tears are not a regulated way to get rid of salt and other minerals (neither is sweat). All mammals use their kidneys for this -- every single one. Tears are not even hypertonic for the (unspecified) minerals found in water and cannot do what AAT/H proponents claim for them. Tears are, however, strongly hypertonic in regard to potassium and that does indicate what environment we developed in. That environment is terrestrial, not aquatic. (The salt glands of terrestrial birds and reptiles are specialized for excreting potassium.)

If the minerals are unspecified, I'm not sure we can know how hypertonic our tears are to them! More to the point, this doesn't prohibit the case for the amphibious ape, and it does nothing about why humans would have a taste for mineral water.

Crocs: crocs are not usually seen before they attack, so strike that fantasy method of defense. The notion of hominids killing crocs (other than infants) in the way gwolf suggests is nonsense. For one thing, we find that during croc attacks now, with much better weapons, spears, rocks, and clubs are ineffective; crocs basically ignore them. And this doesn't take into account that crocs are often found in great numbers. The claim also ignores that large cats can and do effectively chase their prey into water where the bounding moves of the cat offer greater mobility than the running or (very) slow swimming speeds of hominids -- this, BTW, is not uncommonly seen on nature shows, so even watching TV should have shown the writer the error in the claim.

Crocodiles were a regular part of the diet of the hunter-gatherers of Africa (per Richard Leakey) -- unlike other predators like the big cats. So there must have been some reason why this particular predator became endangered. The ease or difficulty of hunting crocs is temperature dependent, and would favor hominids over the crocs in the high rift lake valleys. To raise their temperatures, especially in the morning, crocodiles must bask. This is when they would end up vulnerable, not while pretending to be attack submarines on the prowl. So here is the complete strategy. Hominids approach new lake. Beyond getting anymore than a quick drink, they stay out of the water, until they've walked all the way around the shoreline in the morning, when they'd be able to observe any basking beaches. When they found crocs, they'd cut down some tree branches, strip them to make rough poles and approach the crocs. If they detected the hominids, they would turn headon towards them and gape, the classic crocodilian threat display. If the humans weren't detected, they could easily toss a rock. At any rate, as soon as the croc gaped, the branch would be shoved as far down its throat as it would go, shoving slightly upwards so as to concus the brain. This technique would take advantage of the crocs' exothermic nature, instinctive threat display, the humans' endothermy, group cooperation and ability to learn swift voluntary muscle movement, It might take more than one episode to do this, if there was a chance that other crocs would charge with a closed mouth. Meanwhile, once the basking beach was discovered, a careful note could be made of when any or all were in the water, and therefore a danger to humans. Crocs are territorial, so there'd be a limit to how many any lake would have.

Mating face to face, as done also by orangs, black-handed spider monkeys, and occasionally in woolly spider monkeys and gorillas, and among aquatic mammals done by very few, almost all fully aquatic for tens of millions of years.

Here again this doesn't prohibit an amphibious ape. But remember, I'm positing what I say for a modern H. Sapiens. I'm sure you are as aware as I am of the number of people who associate mating with warm waters -- not only in lakes but hot tubs, spas and (awkwardly!) bathtubs. I should also note that entering water increases the urge to urinate. I can think of a good reason why the urge would exist for a terrestrial ape.

"the opinion seems to be that an aquatic or semi-aquatic environment seems to preserve more fossils than a jungle environment. Thus a plethora of hominid fossils indicates a semi-aquatic environment and a paucity of pongid fossils indicates a jungle habitat..."
The study of taphonomy is apropos to the AAT/H, but we do not have anything like a "plethora of hominid fossils". Suid (fossil pigs of various kinds) are something we do have a plethora of, as we do of many shoreside animals. The relatively few hominid fossils indicates they weren't typically found in the easy to fossilise environments like the shoreside.

Then I guess it's a battle of quotes with the other poster!

The fossil record tells us that certain carcasses fossilize, and that they are more likely to fossilize in places where they are buried rapidly -- usually in mud. It does NOT tell us how likely fossilization is. We know that in places where fossilization is the result of burial alive (such as in tar pits), smarter animals like hominids avoid such overt fossilization attempts. In reading about the KT boundary, I've discovered enormous debates about the time's extant biome because fossilization preserved different things in different places.

Actually, groups in open country seem to rely more on stalking [instead of ambush], although they also use chase (persistence hunting). Our sweat glands help here; if you start at the hottest time of day in a very hot period of the year (as such chases do) we can run for long periods of time at a speed slower than the speed of the prey. This wouldn't work except that our eccrine sweat glands can keep going and going, cooling us, while the aprocrine sweat glands of the prey work quite nicely for about 20 minutes, after which they need to be recharged. Persistence hunting capitalizes on this, because the prey gets out front, but then has to rest or grow more and more tired due to overheating. This works well... for the humans.

This still doesn't rule out the amphibious ape! Eccrine sweat glands are a big disadvantage for any creature that can’t quickly replace all of the water that they use up. That certainly doesn’t seem an argument in favor a dessert or savanah ape, but would keep the amphibious ape closer to ideal operating temperature with the ready water supply. Aprocrine (I think you mean apocrine, by the way) sweat glands are actually special purpose scent glands rather than evaporant cooling devices.

JimC says: "Also, humans have vastly better abilities at throwing than chimps..."

Average human vs. average chimp? Not from what I've read. We can certainly get really good, but then what highly trained atheletes can do is not what's at issue. Chimps (and other primates) are quite good at throwing, strong and pretty accurate.

Constantly throwing shellfish to shore wouldn’t hurt our abilities at all. It would provide sufficient incentive for the “average” amphibious hominid to be an excellent thrower and catcher.

Fish being considered better than many other meats is due to our present circumstances where one can (if you're not in poverty) typically get as much meat as you want, as well as fat, salt, and other useful items that are problematic in large amounts. In earlier times these things were hard to get, virtually impossible to get too much of, and that's why we have appetites for these things. Now that we can get as much as we want these appetites are a problem, but before we could get as much as we wanted those appetites were the solution, making us work to get these hard to get food items.

Eh? What happened to the old anthropological view that hunter-gatherers actually lived pretty well? I’ve heard that among Southern Sudanese tribes, dieing of hunger was considered an embarrassing disgrace – not worth burying the victim (all that changed during the civil war). Further, even with Africa as populated as it is now, the Rift Lakes are still a source of fish. I don’t see any case for their scarcity. Finally, this does nothing to explain why humans have so much trouble digesting cholesterol and certain other ingredients absent from fish meat, but present in avian and especially in mammalian meat.

gwolf then picks up an old Morgan tack: claiming that we should resemble distantly related mammals more than our close relatives (for instance, patas monkeys, which cool via eccrine sweat glands as we do -- and which live in open country). This is ignoring phylogeny, the central tenet of evolution, which is a very odd thing to do.

I would like to note that Erythrocebus patas, the fastest running of all primates, is COVERED IN HAIR like our close relatives and unlike Homo Sapiens. Something’s wrong. Where did I “pick up” an old Morgan trick?

"

...impossible before the invention of highly portable water-carrying tools. For this reason, I suggest that evaporant cooling could never have evolved in an arid climate. Otherwise, other creatures besides h. sapiens would probably have discovered it first."

A twofer from gwolf: first assuming that his ancestors weren't as smart as chimps, which in arid regions dig for and carry water-filled tubers (note: I'm sure MY ancestors were as smart as chimps, or close to it.) then ignoring that other creatures (other primates, in fact) have "discovered it" as well as assuming that creatures can ignore phylogeny as he does. (They can't; you shouldn't; don't do it.)

I believe you’ve just shown us an alternative way to carry water, not a reason why the amphibious ape could not have existed. I will add; do chimps carrying such water-filled tubors sweat with eccrine sweat glands, and hunt their prey to exhaustion as humans are supposed to do?

DHA is available directly or indirectly in terrestrial sources. Other required nutrients are found more easily in non-shoreline diets than shoreline, according to actual studies. You don't need all that much DHA, and the idea that DHA somehow makes your brain big is crazy talk. Now here the researchers Crawford, Cunnane et al. take a wild leap from the data. They seem to be good nutritionists but know little about evolution and have made little discernable attempt to learn. They claim, and others foolishly follow them on this, that getting more DHA makes your brain big, but if this were true we'd see fish-eating species all being smarter than they are; it turns out only a very few are relatively smart (say as smart as your average woodland dwelling primate).

We still haven’t found something that rules out the amphibious ape or explains why humans can eat fish meat better than either bird or mammalian meat.

I'm falling asleep from exhaustion, and I'm not sure I've gotten all the typos out of this. Anyway, this was a good challenge.

George Wolf

[anthrosciguy]

"In fact on the savanna, humans are still ambush predators, using weapons (like spears, arrows and guns) to compensate for the lack of speed."

Yes but that doesn't mean we evolved on the Savannah. After all, we would have to have those weapons in the first place right?

I didn't write that, I quoted it and then responded to it with info more accurately describing our hunting techniques -- those which were likely to be used by "early-ish" hominids -- for instance, no nets or snares or deadfalls, which are great hunting innovations but probably fairly far into erectus times.

And doesn't Crawford state in his example that:

A study of savanna and other African species show that as they evolved larger and larger bodies, the relative size of the brain diminished logarithmically with increase in body weight (1,4). A cebus monkey of 0.9 kg body weight has 2.3% of its body weight as brain, a 60 kg chimpanzee 0.5%. The larger gorilla at 110 kg has only 0.25% brain which is physically smaller than the chimpanzee’s brain. At the extreme, the one ton rhinoceros has <0.1% with its brain weighing only 350g. It reaches that massive one ton body weight at four years of age.

So unlike normal Savannah dwelling animals, somehow we got intelligent?

Crawford has here done something I've seen him do before, and it shows he either doesn't know what he's doing or he's being deliberately dishonest -- I have no idea which. He's cherry-picking. He starts there with a sentence which implies that the brain size to body size diffs are only seen in savanna animals when it's a well known, long-studied phenomena that happens with all animals. Then he just mentions a few animals apparently at random, with no regard for the factors that research has shown are applicable in studies of brain size. (This is what's called EQ, which refers to the comparative size brain we expect from a animal of a given size and what we actually see. As examples, social animals tend to have larger brains than non-social animals; predators tend to have larger brains than prey, and the ratios in determining EQ tend to break down with very large animals such as the rhino he brings in. I've got a page on EQ on my site, so I won't try to mention all of it here.) He pointedly does not mention that primates such as savanna baboons and savanna-woodland vervets have higher EQs than their forest cousins, even though that would seem to be directly apropos, far more apropos than rhinos. So why rhinos and not baboons and vervets? So his central claim is simply untrue, which for me sorta puts a damper on an idea.

Fish being considered better than many other meats is due to our present circumstances where one can (if you're not in poverty) typically get as much meat as you want, as well as fat, salt, and other useful items that are problematic in large amounts. In earlier times these things were hard to get, virtually impossible to get too much of, and that's why we have appetites for these things. Now that we can get as much as we want these appetites are a problem, but before we could get as much as we wanted those appetites were the solution, making us work to get these hard to get food items.

Ummm, no. Fish is considered better because it is healthier for us.

If we now examine the contemporary evidence on cardiovascular disease we find that land
based animal fats have been causally linked to heart disease as revealed by the Seven
Countries study of the 1950s and even earlier

Whilst.....

Worldwide diets and cardiovascular risk factors show that marine fats, especially DHA, are cardioprotective

The thing is that until very recently (in evolutionary terms, say about 10,000-15,000 years ago -- to be generous to your position) it was virtually impossible to get enough fat from any source to hurt us, while the actual problem was getting enough fat (and salt). We also very rarely lived long for fat-related health issues to be any problem even if we were talking about modern "western" diets. Our modern longevity and diet is not what we faced until very recently).

So we are stating that fish is better for your body here. Also Crawford made an interesting remark that:

It is of interest that the Turkana have the highest mitochondrial DNA diversity of any ethnic group. In fact 36 Turkana people have a higher diversity than the world-wide population database. The simplest interpretation is that humans date back to the East African Rift Valley

So its not just, we've got the most fossils here so it must be here, it is also the MitDNA that is helping prove these ideas by stating that the highest diversity is found at Lake Turkana.

Since this area is one of the places we see very early hominid fossils it wouldn't be surprising to note that it's likely to be the place where early hominids lived. The mtDNA evidence there though would not be (AFAIK) from very early hominid days, since we have the whole mtDNA "Eve" (worse naming ever for a scientific idea) which shows a bottleneck at a period somewhere around 200,000-400,000 years ago. I don't know what Crawford thinks he's doing with that info, but it seems he's once again tripping himself up due to being a nutritionist rather than an evolutionary scientist, which wouldn't be a problem if he did the study he needs to do before making pronouncements based on evolutionary science.

DHA is available directly or indirectly in terrestrial sources. Other required nutrients are found more easily in non-shoreline diets than shoreline, according to actual studies. You don't need all that much DHA, and the idea that DHA somehow makes your brain big is crazy talk.

Why, you can't just say, "crazy talk"? I can definitely say that people have it prescribed to increase coherency. I used to take a form of DHA since I have a form of dyslexia and I could definitely tell that the DHA helped. Anyway, the argument was that DHA helped development and brain structure. Since you are claiming they are nutritional biochemists, shouldn't they be able to recognise the reasons why fish is good for you. We might not need that much DHA *now* however, what about the evolving brain structure of the other hominids? After all, I bet their EQ1 went up a lot.

They (and you) are conflating two things which don't fit together. Crawford (and his colleagues, like Cunnane) are -- from what I've seen -- good nutritionists, and rightly concerned about DHA in the modern diet. Not enough DHA can be bad (esp. during development) and since our diets don't tend to have lots of wild game and appropriate plant oils (and less breastfeeding) it's easy to not get enough DHA or the precursors that our bodies can make DHA from. But then they goof big time when they try to hook their campaign to a dubious idea, and the assumption that feeding DHA to a given species makes its brain expand is indeed either crazy or simply appallingly ignorant of how evolution works. It also ignores that if this were true, we would expect to see all seals being very large brained (and they aren't), as well as herons etc. This is one of those instances where nature has already performed the experiment for us, and it just doesn't work the way Crawford and friends want it to.

They claim, and others foolishly follow them on this, that getting more DHA makes your brain big, but if this were true we'd see fish-eating species all being smarter than they are; it turns out only a very few are relatively smart (say as smart as your average woodland dwelling primate).

Which could argue for another evolutionary pressure occurring? I think we covered this earlier. Since we are social animals, I think our combined evolution of the society and the language which may have been caused by the bigger brains, could have created this rather than other animals. So perhaps it is the fact we are social animals which helped the evolution more than anything else. Environmental determinism isn't always something I like to argue for to be honest.[/quote]

Well, that's another good reason to stay away from arguing for the AAT/H, since it is primarily an environmentally deterministic idea. The idea that social interaction, that is the idea that virtually all mainstream paleoanthropologists accept to a large degree, is far more sensible and fits the facts, so I think you should go that route. It entails dropping the AAT/H, but that's not a bad thing to do.

[anthrosciguy]

Now, I would like to repeat something that I said in past quotes that you wouldn't be able to tell from the forum title. I am an advocate of an amphibious rather than an aquatic ape. I see an animal that enters the water to frolic forage or fish, but not much of anything else – except sex perhaps.

Streamlined shape: NOT. Plus early hominids had virtually the same bodily dimensions as bonobos, and little different from common chimps.

Have you got a study saying how modern human swimming efficiency is supposed to be less than or no better than the other apes? Can they swim? How well do they swim? I'm more interested in this than in comparing humans to other amphibious mammals because h. sapiens is a very new species. It is in effect a transitional form, not fully adapted to amphibious life. I’d predict it swims better than other apes, but not as well at all as other amphibious tetrapods.

Apes don't seem to swim very well, and our closest relatives the chimps are really bad at it -- in fact it's often said they can't swim, which isn't true, but certainly they do so extremely rarely and many don't know how to swim at all. (It should be remembered that this is also true of many humans.) I don't think there's any comparitive swimming data, but overall we seem to be much better swimmers than apes -- but then there are also monkeys which swim well (and dive, BTW). (It's also often incorrectly claimed that some of these monkeys also are bipedal more often than other primates but this is untrue.)

I don't think that any AAT/H advocate espouses a truly aquatic animal, although Hardy suggested about the degree of aquaticness as an otter. Everyone since has backtracked far away from Hardy's claims, although generally they have done so with no specific degree of aquaticness mentioned. They then tend to jump around in how much aquaticism there was, making it a lot or hardly any depending on ad hoc responses to critics -- they are very reluctant to be clear about what exactly they are arguing. Except that when you see the characterisitics they use as evidence, they are necessarily talking about resembling whales, serenia, and seals (because those are the aquatic mammals which have the characters they claim -- inaccurately -- we have). This means they are left claiming that somehow, in some unspecificed way, some unspecified degree of walking along the shore and sometimes swimming for wading results in having the characteristics of mammals which have fully aquatic for tens of millions of years -- in some cases longer than the entire primate line has existed. How this is supposed to happen is never explained. But the bottom line problem is that the more sensible you try to make the theory by making the degree of water use less the more the theory doesn't work.

Swimming efficiency for humans is terrible; most of competitive swimming coaching is
how to decrease the naturally poor efficiency of human swimming. If human hair patterns are due to slection for swimming, why is it that the one thing competitive swimmers want when they race is what we don't have -- they either shave their hair or use body suits which mimic the effects of hair, or dermal ridges as seen in dolphins.

We have far less hair than do other apes already. Others on this list have pointed out that ape hair causes more drag in water than that of other mammals. Male pattern baldness decreases hair on a leading edge that most aeronautical engineers would want as smooth as possible. Conversely, beard hair would tend to smooth the neck's natural drag cavity. Pubic hair might do the same for the genitalia.

I don't know that ape hair would be any less hydrodynamic than that of other mammals, except that they, and we, have philoerector muscles which can make the hair stand up. (Seals, for instance, do not have these muscles.) Bottom line again: we have a natural condition re hair that is a middle ground which turns out to be exactly, precisely, what competitive swimmers do not want; why did our past supposed finetuning for millions of years result in exactly the wrong thing?

Crocs: crocs are not usually seen before they attack, so strike that fantasy method of defense. The notion of hominids killing crocs (other than infants) in the way gwolf suggests is nonsense. For one thing, we find that during croc attacks now, with much better weapons, spears, rocks, and clubs are ineffective; crocs basically ignore them. And this doesn't take into account that crocs are often found in great numbers. The claim also ignores that large cats can and do effectively chase their prey into water where the bounding moves of the cat offer greater mobility than the running or (very) slow swimming speeds of hominids -- this, BTW, is not uncommonly seen on nature shows, so even watching TV should have shown the writer the error in the claim.

Crocodiles were a regular part of the diet of the hunter-gatherers of Africa (per Richard Leakey) -- unlike other predators like the big cats. So there must have been some reason why this particular predator became endangered. The ease or difficulty of hunting crocs is temperature dependent, and would favor hominids over the crocs in the high rift lake valleys. To raise their temperatures, especially in the morning, crocodiles must bask. This is when they would end up vulnerable, not while pretending to be attack submarines on the prowl. So here is the complete strategy. Hominids approach new lake. Beyond getting anymore than a quick drink, they stay out of the water, until they've walked all the way around the shoreline in the morning, when they'd be able to observe any basking beaches. When they found crocs, they'd cut down some tree branches, strip them to make rough poles and approach the crocs. If they detected the hominids, they would turn headon towards them and gape, the classic crocodilian threat display. If the humans weren't detected, they could easily toss a rock. At any rate, as soon as the croc gaped, the branch would be shoved as far down its throat as it would go, shoving slightly upwards so as to concus the brain. This technique would take advantage of the crocs' exothermic nature, instinctive threat display, the humans' endothermy, group cooperation and ability to learn swift voluntary muscle movement, It might take more than one episode to do this, if there was a chance that other crocs would charge with a closed mouth. Meanwhile, once the basking beach was discovered, a careful note could be made of when any or all were in the water, and therefore a danger to humans. Crocs are territorial, so there'd be a limit to how many any lake would have.

We tried to wipe out crocs; we really did, but rather more recently that you suggest. In spite of having infinitely better weapons than our ancestors we didn't get anywhere until we got to the guns and habitat destruction phase. This is not surprising since crocs typically suffer enormous predation until they reach maybe 6 feet in length or so and have adapted for that kind of predation (somewhere betweem 95-99% of all Nile crocs, for instance, never make it to adulthood, yet they were, until very recently found in massive numbers, and this is true for other crocidialians).

Mating face to face, as done also by orangs, black-handed spider monkeys, and occasionally in woolly spider monkeys and gorillas, and among aquatic mammals done by very few, almost all fully aquatic for tens of millions of years.

Here again this doesn't prohibit an amphibious ape. But remember, I'm positing what I say for a modern H. Sapiens. I'm sure you are as aware as I am of the number of people who associate mating with warm waters -- not only in lakes but hot tubs, spas and (awkwardly!) bathtubs. I should also note that entering water increases the urge to urinate. I can think of a good reason why the urge would exist for a terrestrial ape.

Of course vento-ventral mating doesn't prohibit it, but the claim was made that this was evidence for it yet it's done by many terrestrial mammals, including primates, and only by some aquatic mammals. It just isn't the evidence AAT/H proponents say it is. The increase in the urge to urinate is actually covered on my site, BTW, since it's part of yet another bit of evidence where Morgan claimed some things that just weren't true, did a little creative editing, and got caught. It's the page entitlted "Aldosterone, water, and bipedalism".

"the opinion seems to be that an aquatic or semi-aquatic environment seems to preserve more fossils than a jungle environment. Thus a plethora of hominid fossils indicates a semi-aquatic environment and a paucity of pongid fossils indicates a jungle habitat..."
The study of taphonomy is apropos to the AAT/H, but we do not have anything like a "plethora of hominid fossils". Suid (fossil pigs of various kinds) are something we do have a plethora of, as we do of many shoreside animals. The relatively few hominid fossils indicates they weren't typically found in the easy to fossilise environments like the shoreside.

Then I guess it's a battle of quotes with the other poster!

The fossil record tells us that certain carcasses fossilize, and that they are more likely to fossilize in places where they are buried rapidly -- usually in mud. It does NOT tell us how likely fossilization is. We know that in places where fossilization is the result of burial alive (such as in tar pits), smarter animals like hominids avoid such overt fossilization attempts. In reading about the KT boundary, I've discovered enormous debates about the time's extant biome because fossilization preserved different things in different places.

The study of taphonomy is the study of how likely fossilization is. It's well known and well supported. It indicates that if our ancestors were living in the places ATT/H proponents say they were we'd be inundated with their fossils, and we aren't.

Actually, groups in open country seem to rely more on stalking [instead of ambush], although they also use chase (persistence hunting). Our sweat glands help here; if you start at the hottest time of day in a very hot period of the year (as such chases do) we can run for long periods of time at a speed slower than the speed of the prey. This wouldn't work except that our eccrine sweat glands can keep going and going, cooling us, while the aprocrine sweat glands of the prey work quite nicely for about 20 minutes, after which they need to be recharged. Persistence hunting capitalizes on this, because the prey gets out front, but then has to rest or grow more and more tired due to overheating. This works well... for the humans.

This still doesn't rule out the amphibious ape! Eccrine sweat glands are a big disadvantage for any creature that can’t quickly replace all of the water that they use up. That certainly doesn’t seem an argument in favor a dessert or savanah ape, but would keep the amphibious ape closer to ideal operating temperature with the ready water supply. Aprocrine (I think you mean apocrine, by the way) sweat glands are actually special purpose scent glands rather than evaporant cooling devices.

Yes, it was a typo. Aprocrine glands do provide some scent, although sebaceous glands are more for that purpose, but they definitely do provide cooling, albeit not as usefully as our eccrine glands.

gwolf then picks up an old Morgan tack: claiming that we should resemble distantly related mammals more than our close relatives (for instance, patas monkeys, which cool via eccrine sweat glands as we do -- and which live in open country). This is ignoring phylogeny, the central tenet of evolution, which is a very odd thing to do.

I would like to note that Erythrocebus patas, the fastest running of all primates, is COVERED IN HAIR like our close relatives and unlike Homo Sapiens. Something’s wrong. Where did I “pick up” an old Morgan trick?

Tack, not trick (unless you meant to deceive). What's wrong with our resembling our primate relatives in some ways and not in others? This is what we see in countless species, both animals and plants -- it's normal.

"

...impossible before the invention of highly portable water-carrying tools. For this reason, I suggest that evaporant cooling could never have evolved in an arid climate. Otherwise, other creatures besides h. sapiens would probably have discovered it first."

A twofer from gwolf: first assuming that his ancestors weren't as smart as chimps, which in arid regions dig for and carry water-filled tubers (note: I'm sure MY ancestors were as smart as chimps, or close to it.) then ignoring that other creatures (other primates, in fact) have "discovered it" as well as assuming that creatures can ignore phylogeny as he does. (They can't; you shouldn't; don't do it.)

I believe you’ve just shown us an alternative way to carry water, not a reason why the amphibious ape could not have existed. I will add; do chimps carrying such water-filled tubors sweat with eccrine sweat glands, and hunt their prey to exhaustion as humans are supposed to do?

Again, why are AAT/H proponents, in my experience, so often flabbergasted that we resemble our closest relatives in many ways and not in others, just as we see in countless species, both animals and plants?

Finally, gotta say I don't care for the quoting system in this forum; makes it hard to not get wrong attributions and/or sloppy hard to follow posts. Hope I've gotten them more or less there.

[anthrosciguy]

Swimming efficiency for humans is terrible; most of competitive swimming coaching is
how to decrease the naturally poor efficiency of human swimming. If human hair patterns are due to slection for swimming, why is it that the one thing competitive swimmers want when they race is what we don't have -- they either shave their hair or use body suits which mimic the effects of hair, or dermal ridges as seen in dolphins.

It may be "terrible" w/r to say, dolphins, but humans never got to be fully aquatic, obviously. The point is that hair loss (except on the head, where it had other uses) w/r to the common ancestor does improve swimming efficiency, as you implicitly acknowledge with your remarks about instructors.
Maybe hair loss was the "quick and easy" evolutionary solution to improved swimming efficiency. Full shape streamlining would obviously take much longer.

My remarks about instructors has nothing to do with hair loss; I was referring to the amount of work they do with competitive swimmers to cut down on turbulence caused by our swimming motions, which is awful compared to any animal which commonly swims as part of its typical lifestyle. The point is that we would expect to see one of two things --hair-wise -- if we were adapted to swimming:

1. no hair
2. lots of hair (and probably no philoerector muscles)

Instead we have exactly the inbetween condition; exactly what's wrong for swimming, and this is supposedly what millions of years of evolutionary fine-tuning got us. That doesn't make sense.

Further streamlining would not likely be so long to get, and this is another pet peeve of mine about AAT/H proponents' methods. When they've got something that should be seen but isn't they say "not enough time" yet there's loads of time for radical, even bizarre changes (even bizarre changes that change back without a trace). This doesn't make sense. But we can get an idea of how long streamlining takes to appear in mammals by looking at polar bears, which are streamlined compared to their relatives the brown bears and have gotten that way in only a few hundred thousand years -- yet for humans apparently even millions of years isn't enough.

An interesting trivia note about the AAT/H is that while it's proponents continually point to false "facts" about similarities between humans and aquatic animals supposedly due to convergent evolution, they pointedly ignore the actual ubiquitous aquatic traits seen in aquatic animals due to convergent evolution. One of the main AAT/H methods, ironically, is to ignore actual aquatic traits in favor of make-believe aquatic traits.

[DavidMcC]

Jim, you previously argued that if a man shaves his body hair, it makes little difference to his swimming efficiency, now you claim our body hair is a problem. You can't have it both ways!

[Largenton]

I didn't write that, I quoted it and then responded to it with info more accurately describing our hunting techniques -- those which were likely to be used by "early-ish" hominids -- for instance, no nets or snares or deadfalls, which are great hunting innovations but probably fairly far into erectus times.

Quick question. Would you compare the early hominid to the Hunter-Gatherers of today in that they hunted and gathered? I'm not trying to compare techniques, instead I just want to know if thats the lifestyle you would prescribe to them?

I don't know what Crawford thinks he's doing with that info, but it seems he's once again tripping himself up due to being a nutritionist rather than an evolutionary scientist, which wouldn't be a problem if he did the study he needs to do before making pronouncements based on evolutionary science.

Actually its extremely relevant. When he is looking at DHA he is looking at homo sapiens, not other hominids so stating that we come from this area, although it originates from a bottleneck phase means that its generally correct. You could just read the article, I gave a link on page 2.

It also ignores that if this were true, we would expect to see all seals being very large brained (and they aren't), as well as herons etc. This is one of those instances where nature has already performed the experiment for us, and it just doesn't work the way Crawford and friends want it to.

And you are possibly ignoring the ideas that our evolution of the brain was encouraged by DHA and additional factors which I mentioned in the last post.

Well, that's another good reason to stay away from arguing for the AAT/H, since it is primarily an environmentally deterministic idea. The idea that social interaction, that is the idea that virtually all mainstream paleoanthropologists accept to a large degree, is far more sensible and fits the facts, so I think you should go that route. It entails dropping the AAT/H, but that's not a bad thing to do.

Ummm, I'm not arguing for AAT/H, I'm more of a fan of Bailey's ideas to be honest.

[edit]

Oh yeah, just to say something on the swimming, to teach an athlete how to swim competitively, takes years of training, etc. However, to teach a normal kid to swim efficiently (as I used to do in my job) takes less than 5 years. Bearing in mind, when I was teaching these kids to swim in those 5 years I spent only 30 minutes a week with a class and taught up to 20 children. Give me a single child at the age of 5 and I could probably teach them by myself to swim correctly and efficiently much quicker, at least a quarter of that time I would imagine. Also, I have never had a kid, even the ones with special needs, that could not swim. The only times I have had problems is when the child will not listen to you (which I blame more on the parents fault) so will not learn.

Just to fill in the background there, I am 19 and have been assisting and teaching for over 6 years. I have the ASA Swimming Teacher's level 1 certificate and I taught for Swim Stockport for a few years. I am also considered a good teacher as well. Just so you know about these things.

[DavidMcC]

The point is that we would expect to see one of two things --hair-wise -- if we were adapted to swimming:

1. no hair
2. lots of hair (and probably no philoerector muscles)

What if, as has been suggested before, it was only or mainly the females who did the swimming (as gatherers), bearing in mind that there are limits to sexual dimorphism in mammals.

[Largenton]

Just to further back DavidMcC up there, women are better at swimming at men. So swimming is more natural to them.

[DavidMcC]

Furthermore, we all know that women are not averse to some hair on men, but men are rather averse to hair on women (as discussed on another thread -apologies to NakedCelt!). This doesn't make sense on the basis of hair loss for cooling on the savanna, but does on the basis of the aquatic ape.
(BTW, before you talk about sexual selection sometimes being contrary to natural selection, I don't accept that. For example, as discussed on a previous thread here, the peacock's tail's eye-spots served a dual purpose of attracting the peahen and confusing/scaring the predator, due to the appearance of a large animal with many eyes as it swings the tail round.)

[rationalrevolution]

There is a whole lot of absurd speculation in this thread.

And as for sexual selection, yes, there definitely are cases of selection for features that have no survival benefit.

While this is purely speculation, I think that the loss of hair would more likely have been impacted by mud than actual swimming. This would be consistent with a swampy lifestyle that included a lot of wading and digging in mud for shellfish, etc.

Wading would also have led to a selection for longer legs as well, which is a feature of people vs the other apes. I don't see swimming doing this, indeed just the opposite.

[DavidMcC]

Rationalrevolution, although there is certainly a lot of speculation on this thread, not all of it is absurd. However, what would be absurd is for sexual selection to reverse the gender difference in hairiness. Do you know of any species where reversal could have occurred for purely sexual selection reasons?

BTW, the early part of the aquatic period would not have involved much mud, once a beach had formed (after the presumed catastrophic flood of the Afar depression had given way to a normal marine coastline). Sure, wading would have preceded swimming, but swimming could have followed.