How come you people never come visit? I'm only an hour from the freeway by way of a two-lane county road, roughly equidistant from Fargo, Sioux Falls, and Minneapolis, yet somehow no one ever happens to be passing through this remote rural town … until today. Jim Moore took a little detour from his road trip from Victoria, BC to Oklahoma to pop by lovely Morris, Minnesota and say hello. Now we expect the rest of you to come on by.
In case you don't know who Jim Moor is, he maintains this web page, a critique of the Aquatic Ape "Theory". This "theory" (really, it doesn't deserve the promotion) is often taken as quite reasonable at first glance — hey, whales have reduced body hair and are aquatic, humans have reduced body hair so maybe they also went through an aquatic stage in their evolution — but once you dig just a tiny bit deeper, the inconsistencies within the hypothesis and the contradictions with reality loom larger and larger, and you really should realize that it's utter nonsense. But weirdly, there are a number of people who have gotten quite obsessed with the idea and who have written reams of papers to rationalize the baloney. Back in the 20th century wrangles over the Aquatic Ape nonsense would spontaneously emerge on usenet all the time (here's one example) because its proponents had to be completely refractory to contradicting evidence. Good times.
One interesting twist to it all is that it's an odd variant of denialism. These people aren't rejecting an established scientific conclusion, such as that HIV causes AIDS or that human activities contribute to global warming — they are pushing beyond reason for a conclusion that science denies. I suppose you could say they're denying the evidence that shoots down their favored beliefs, but at least they actually have a positive (but bogus!) hypothesis that they aren't afraid to recite at you, which puts them several notches above the Intelligent Design creationists.
Anyway, Moore has a tremendous amount of useful information rebutting the Aquatic Ape Speculation — it's well worth a browse, and also amusing to read some of the crackpot defenses (one of my favorites is the claim that Neandertals had large noses that they used as snorkels). And I'm not just saying that because he was nice enough to stop by Morris!
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Ouch... when the aquatic ape people are several notches above you, you know you've done bad.
Jim Moor really saved me a couple of years ago when the AA people started their Gish gallop on me and I was not ready with all the answers - I found Jim's site (Googling, probably) and there it all was, nicely organized.
On Visits...
Tell you what, you pay for round trip train tickets to the nearest train station, I'll drop in for a few days. (I'm not putting myself through any sort of airport check in, the panic attack would only put me in hospital for a long stretch.)
On The Aquatic Ape Theory
Well first, we're not hairless. Check out the nearest available 5 year old for example. Real fine, light hair over almost every square inch of skin, but hair.
Then there's the matter of proportions. Long limbs do not lend themselves to heat retention. Nor does the lack of sub-cutaneous insulation in hominids of tropical provinence.
That alone convinced me that the whole aquatic ape thing has nothing going for it.
On my way to Madison I drove through Minnesota, on HWY 90. I would have tried to swing up north (calling first) if we weren't so pressed for time. It's hard to drag oneself from Wyoming to drive through the monotony of 90. I'm sure you've driven on it! Still, there will be other opportunities in the future...
Never could quite see how apes would be aquatic. My impression is that people don't swim a lot in Africa where we evolved.
Just about every large body of water has crocodiles. Big crocodiles with lots and lots of teeth. Hippopotamuses are almost as bad, big and mean, people avoid them.
There are a lot of water associated diseases. Malaria from their vector mosquitos. River blindness from black flies that carry worms, schistosomiasis, plus the usual water borne diseases such as amoebas (giardia), enteric bacteria, hepatitis A etc.
Neither the common chimpanzee nor the bonobo swim. Large rivers are effective isolating features for these two species.
Elaine Morgan promoted the AAH rather heavily in Britain, and appears to have done so in part to construct a version of human evolution that was more user-friendly to feminists. As I recall, she was particularly hard on Desmond Morris's book 'The Naked Ape' as another example of 'male-centered' theorizing.
It's interesting to note, then, that Morris (and David Attenborough) have since acknowledged that there may have been something like a semi-aquatic episode in the line that led to modern humans: that is, they weren't truly aquatic, but extended periods spent wading in water shaped the populations in various ways, and (perhaps) helped promote habitual bipedalism. I would be really interested in hearing any adaptive explanation for the diving reflex in human infants that doesn't involve water!
In fact, I've thought it would interesting to get several sets of female twins (please, no jokes)---and treat them identically, controlling for everything except that one twin would spend 4-6 hours per day wading in neck-deep water, and the other not. At the end of so many weeks of this treatment, compare their blubber---excuse me, I mean their subcutaneous fat.
(hand in heart) I swear, my only motivation is the science.....:)
Just what I needed to know, another previously unknown, to me, group of kooks with another crackpot "theory".
Sigh.
I guess I could say that ignorance is bliss but all the frantic fools out there put the lie to that saying.
apparently, my paleo prof is an aquatic-aper. i was quite distraught to find this out.
Hey, Aquatic Ape Theory is totally plausible. I mean, otters beavers muskrats and polar-bears are aquatic mammals, and they're all hairless, right?
Scott H.
A partial aqnswer to possible differences in body fat between individuals who are immersed and non-immersed has been done by Gwinup in the 1980's. He found that people who tried to lose weight by swimming were much less effective than those who tried to lose weight with walking/running or cycling. The out of the water exercisers lost considerable weight, as expected, however the swimmers, even though they exercised about as hard for about as long, were not able to lose nearly as much weight, and some actually gained weight. There was no dietary intervention in this study and the body composition measurements were not very good, but it may be concluded that swimmers have bigger appetites. This conclusion has been frequently noticed among coaches. Other fairly old studies show that appetite is increased in people that were immersed in cold water. And competitive swimmers - the athletes who expend more time in their very long workouts - tend to have higher percentages of body fat than athletes who are in a sport out of the water. The oxygen consumption per unit time in a swimming workout is slightly less because of more involvement of smaller muscles with lesser involvement of the larger muscles that are used in land locomotion. AFAIK, there has been no definitive study of hormones related to appetite and satiety in humans, but it appears that immersion is orexigenic.
o·rex·i·gen·ic adj Having a stimulating effect on the appetite.
Going over the top for an engineer / book dealer there, natural cynic.
Moore's takedown of AAT is nicely done, but I think some of the explanations he offers in its place are a bit weak, for example:
He goes on to discuss the distribution of subcutaneous fat and hair, and how humans are nothing like seals in this respect. So far so good. But then to declare that human hairlessness should be "obviously" due to sexual selection? Differences in hair distribution appear at puberty, but that does not explain why humans are (relatively) hairless in the first place.
and, raven:
If prehistoric Africans would have generally avoided water, how did all those parasites and diseases evolve (many have humans as the definitive host)? Since people need to drink/fetch water anyway and can contract the parasites then, it's not a good argument for or against prehistoric skinny-dips.
I remember hearing about AAT a while back. The appeal at the time was for things like nose shape (how come we don't have forward-facing nostrils like other apes?) and seemingly different hair and micturation (ahem) adaptations than other savannah creatures.
Looking at it all closely, though, the bulks of the entire argument falls apart like bus passes in the laundry (no...I'm not bitter...no...I'm not bitter), the fat argument being amongst the most egregious.
The only arguments left, and someone may have torn these apart already, are those of the benefits of bare skin, watery urine and lots of sweat. Having been to east Africa, and having been torn at by acacias and other thorny bits and bit by mosquitoes and ants (and also being ill-adapted in my camouflage against pushy vendors), I must wonder whether we initially evolved somewhere a little nicer (but not water) than the open, dry grassland that rhinos and lions 'enjoy'... and then adapted to the savannah after learning how to clothe and shelter.
Hairlessness does not seem a common adaptation of the critters out there (not in the cats, antelopes, zebras, hyraxes or bovines, including the ever-cute gnus) and it doesn't help against mosquitoes (though the extent to which fur helps is questionable).
Do we pee in a more watery fashion than other savannah mammals? What kind of researcher pursues these sorts of burning questions (more cranberry juice!) for us?
Cynic -> For me and many of those I know, the water doesn't have to be cold or totally immersive. "Post-shower hunger" is an oft-experienced phenomenon here :)
Damn, though, I'll never be able to remember postlauvabrum orexigenesis as a proper term for it...
OK, that was some funny stuff, right there. Natural cynic, thanks for a detailed reply, with sources.
Still, I have to say: what about the diving reflex? (This is the item that so impressed Morris)
"... its proponents had to be completely refractory to contradicting evidence."
a trait they share with about 90% of biologists with a hypothesis... you just end up looking sillier when its about swimming paleo-humans instead of, say, HeLa cells.
You should go and fix the wikipedia page on the AAH.
http://en.wikipedia.org/wiki/Aquatic_ape_hypothesis
Then know the pleasures of having it slowly edited away.
Moore's argument that the transition to water is impossible because of the problem of predation is, I think, worthless. He says that crocodiles and/or sharks would have eaten those early humans as soon as they put a foot in the water (in case of crocs, able to jump vertically 1.5 meters from water level, even before). Maybe Mr Moore has missed the fact that aquatic tourism is one of humanity's largest business, that people travel in their masses to the beach to enjoy swimming and surfing, that crocs, sharks and other river predators are rather scarce in Europe and north Asia's rivers. Many peoples make their living by fishing with nets or lances, or collecting pearls or whatever. Humans love playing in water, sex is best in water, we have no ancestral fear of water and certainly enjoy playing water. In my personal case, younger Kleins are all competition swimmers and waterpoloists, they take part in dozens of open sea or cross river competitions. I have swam in all the Oceans and never, ever, a predator cared to attack me. Should I have the chance, I would voluntarily complete the Klein's evolution to fully aquatic human beings. Another aspect is that many, possibly hundreds of terrestrial mammals did actually make the transition to the water, among them the dolphin (from some type of ancestral dog), the ballain (from a some cow-like creature) and so on. Without taking it personally, I dont think my ape ancestors were less capable or fit that the dolphin's doggish ancestors. Should they put their minds on it, they could have easily made it. Here I stop criticizing Mr Moore's theory, because came to my mind Mr Stuart Pivar's vengeful reaction against Prof. PZ Myers. Should he ever think of sueing me, know I am ready to apologize and publicly state that he is right and the Aquatic Ape is wrong. Very wrong.
In Michael Crichton's novel Next the passage: "According to her reading, the loss of hair had occurred after human beings separated from chimps. The usual explanation was that human beings had become for a time swamp creatures, or water creatures. Because most mammals were hairy their coats of fur were necessary to help maintain their internal temperature. But water mammals, such as dolphins and whales had lost their hair in order to be streamlined. And people, too, had lost their hair."
-- If Michael Crichton things AAH is the mainstream of science you know it is, because he wrote Jurassic Park. So suck it scientists. No other scientific theory explains how humans became bipedal millions of years ago, lost hair hundreds of thousands of years ago, and got fat within the last couple thousand! Can you explain why we believed in mermaids if not for some kind of race memory from our aquatic days?
I recall this topic generating many acrimonious posts in sci.skeptic, back in the very late 1990s.
Even without recourse to the science, it was easy to determine which side had the most cogent and convincing arguments.
Usenet had its day, and it was good... then the S/N ratio dropped precipitously.
Hippopotamuses are almost as bad, big and mean, people avoid them.
"Almost"? Apart from usually being heavier, they'll kill you for trespassing. Crocodiles only bite you when they're hungry. Lots more people die from hippo attacks every year than from croc attacks.
But that's not where we come from!
Far fewer than "hundreds".
The what? La baleine? "The whale"? Firstly, dolphins are whales, more closely related to the sperm whales and the beaked whales than the baleen whales are. Secondly, whales as a whole are even-toed ungulates, and their closest known relatives are the hippos, though the most recent common ancestor of these two groups must have looked more like a duiker. No really cow-like animals are involved, and no carnivorans.
The chimpanzees live north of the Congo, and the bonobos south of it. The (admittedly big) river is all that separates them. Gorillas and orang-utans, too, don't swim.
But that's not how evolution works! A species can only become more aquatic if the best swimmers have the most surviving fertile offspring, and if swimming ability is inheritable. Wanting it doesn't make it so.
This is not exactly an area of expertise for me, but it's one I'm very interested in. I seem to recall that humans (or human ancestors, natch) started using coastal and river shellfish/fish a lot more in their diets around the time that brain growth took a leap upward. Is there any evidence at all for when we might have started to get less hairy, in terms of relative timeline? Is there any particular physical evidence available for or against the idea that our ancestors DID start spending considerable time wading?
I know that there are an awful lot of potential reasons for (relative) hairlessness which don't involve water in any capacity except sweating (which I suspect would be a very important component in allowing long-distance running in the heat). I just wonder if there is anything at all which would link human behavior and bodies to water besides the obvious one of diet.
I remember that theory from when I was in High School!!! I really liked it. After I thought about the claims and learned a bit about biology in my sophomore year I could see it was fundamentally flawed. I can't believe it's still kicking around.
Still, I think it'd make a great premise for a humanoid race in a Sci-Fi MMORPG or something. Sort of a throw-back to some of the Space Opera cliche's.
I've long wanted to do a (hopefully double blind) study which tested the correlation between support for the AAT and personal comfort with being in water.
Having followed SciAnthroPaleo for a while, it appeared one good thing the AAT seemed to have done was demolish the straw man savanna theory in favour of predominantly riverine and maybe sea-shore environments. Yet I still see the seemingly dead savanna revived repeatedly above.
But now it looks like the separation date from our last common ancestor with Bonobos has been pushed back so far before the date of the East African savanna that there has been plenty of time for our sometimes tiny population of direct ancestors to have passed through a few increasing comfort with water selection points without ever getting any closer to fully aquatic than modern day Polynesians or east Asian maritime cultures.
Moore has never given me the impression that he was capable of trying to come to terms with any of the evidence as might befit an argument which PZ has noted is anything but your typical anti-science. And there is still that old truism about the believability of aging scientists who say "impossible".
Is there any evidence at all for when we might have started to get less hairy, in terms of relative timeline?
Yes! Variation in a skin color gene tells us that dark skin in our ancestors was fixed by selection 1.2 million years ago, at the latest. The idea is that hair loss happened sometime before that, and dark skin evolved as protection against the sun. See this article, if you can find it:
Rogers, Alan R., David Iltis, and Stephen Wooding 2004: Genetic variation at the MC1R locus and the time since loss of human body hair. Current Anthropology 45: 105-108.
1.2 mya is way late for the suggested wading scenarios (I think) and way early for advanced cultural innovations, like clothing or shelters, to explain hair loss.
Jim definitely has constructed a great resource on the idea, and I've been contacted by some AAH usenet groups that still seem to be running today whenever I've been disparaging of the hypothesis. Oddly enough I just picked up Morgan's Scars of Evolution last night to see what all the fuss was about, and, with only 50 pages left in the book, Morgan has yet to provide any positive evidence for her hypothesis. Most of the what she says is an attempt to tear down other ideas, thinking that the reader must accept her conclusions by default.
I am surprised at how often it shows up in the popular science literature, though. I wasn't too surprised when Desmond Morris gave it a few lines in The Naked Ape (which was the passage that apparently inspired Morgan to begin with), but I was a bit shocked to see it prominently endorsed in the recent book Survival of the Sickest.
Jim Moor's site gives plenty of compelling reasons to doubt the AA theory. On the other hand anyone who has read the Naked Ape should also read Elaine Morgan's "Decent of Woman". Her takedown of Morris is classic; very funny (I laughed aloud a lot), and for the most part correct. Most of his ideas were based on sexist notions.
The AA theory she replaced it with has been shown to be unlikely, but that should not detract from enjoying her book.
While I think there is little evidence for the AA theory, I think in its original form it talked about seashores not crocodile infested rivers. There are plenty of good food sources along rocky shores - particularly shellfish, and fish were a lot more abundant before we ate them all. Who knows, some of our ancestors may have spent some time there.
My feeding order meant I didn't see Hit the Beach: Why Humans Love Water before I posted above, but it certainly underlines the point that Moore and friends have failed to convince plenty of sincere science affectionados.
(I also failed to do the double check that would have shown that all three mentions of savanna(h) were in the same post.)
I doubt the situation is as black and white as that. Most animals can swim if they are forced to.
Btw, I would like to see some reliable data on this. The web is divided. As Jim Moore himself notes:
And there are more discussions like that on other web sites, but not so much data.
Also, groups of monkeys and apes may for one reason or other seek to water. Beside the japanese monkeys, IIRC Attenborough had some shooting of a group of gorillas who regularly feed half submerged in swamps.
Humans may be unique in some respects, but not in our ability to take to water. Which would be another mistake behind the AA idea.
Moore sets a high standard. Now you expect me to drive up I-35 and veer to the left (is that a political pun you intended moving to Morris?) just to pay you a visit?
It's actually inviting. We spent Saturday driving to Austin to catch a presentation of the "Colleges that Change Lives" bunch, with 36 of the colleges on hand to discuss what they can do for our aspiring-to-a-great-college high school senior.
Lots of great schools, like Kalamazoo, Lawrence (who recruited me to play football -- I've never decided if they were more foolish to do that or if I were more foolish for declining), Austin College (not on Austin -- in Sherman; go figure), Reed, St. Olaf's . . .
Where was UM-Morris? I wondered. If the CTCL book were being published today . . . how are you guys on music and physics?
Oops. I forgot to add that humans may drown when they fall into the water as well. We need to learn how to swim passably in most cases.
I remember that when the AA hypothesis first came out it was in an obviously ideological-literary-pop context. I'm a little surprised it's stuck around for 30 years or more.
I adapted the theory to my own purposes as the "mud wallow ape", imagining proto-humans to be happy swine rolling nude in the mud. Rae Dawn Chong would have starred in the movie.
Maybe I don't understand the question, but Jim Moore discusses this too. Seems it is a shared, possibly ancestral, trait among vertebrates. (Snakes, rabbits, dogs, armadillos, ...) And, oh joy, this time there are references.
The diving reflex argument is dead in the water. All mammals have it, so there's nothing special at all about humans.
UMM has an excellent music program, and I suspect that the only thing that keeps physics from greatness is our size -- we have a small number of faculty, although they are all very, very good. Our selling point, though, is that we are a true liberal arts university, and if you come here for the physics we'll also tell you to take advantage of the music, and vice versa. We pride ourselves on turning out well-rounded scholars.
David Marjanovich objects:
(1) ... possibly hundreds of terrestrial mammals did actually make the transition to the water... He objects to "hundreds" and want dozens. OK, I didnt count them, but a dozen will make my point as well as a hundred. The land-water transition had been successfully carried out be XXX number of mammals.
(2) La Ballain - the whale. You for one understood my intention. Is the argument less valid if one uses a French word?
(3) Whales are not descended from cow-like mammals, you say. OK, they were not cow-like. for my point it is enough that they were terrestrial mammals. (If they also ruminated and had parted hoofs like ungulates, their meat would have been considered kosher for antropoids of the Jewish persuasion).
(4) Apes dont normally swim. But David, I do, we do. So apes didnt pass through an aquatic phase, but we did. We love water. Makes sense?
(5) Evolution does not work that way. Our ancestors did not "want" to evolve. They did not formulate concious strategies. If you say so!
(6) Why I am fat as a pig and have webbed hands?
I have debated this issue for years and gave-up. Pointing at weird claims that some attach to the AA theory does not work. People have often attached the belief in Bigfoot to evolutionary biology, and someone doing so should not be able to discredit actually evolutionary biology.
I have read so many stupid responses above against AA that it makes me sad for science in general. The reality is we do very well living next to water and have many traits one might associate with a semi-aquatic state.
No matter what you try and claim, we will continue to live next to water, and buy swimming pools, and beach front property, and go on paradise cruises of clear blue-green waters, and big leafy green trees and bushes. The beach will always be the human number 1 destination, and many of us see this behavior linked to our physical traits, as giving us an obvious answer to where we came from...
Jim Moore is my hero. His site is really worth reading, and fun too. For people that want to learn more about biology and evolution, I think it can work as a twisted but excellent introduction.
My introduction to AAT was via 'The Descent of Woman'. Elaine Morgan is a brilliant writer, and she gets across her ideas so well that I found it very difficult to let go of the theory because of that. I'd still recommend 'The Descent of Woman' as an introduction to sexism in science, but probably after you've been told about the problems with AAT (though I really don't like the design of that site linked to - I find it very difficult to read on that muddy background).
I first ran into the AA postulation back in the 80's. It was being sold at the time by a small group of heavy drinking, male hostile, ultra-feminists. These women remind me of the current creationists in that any questioning of their pseudo-science was just trying to destroy god in one instance and women's dignity in the other.
How come you people never come visit? I'm only an hour from the freeway by way of a two-lane county road, roughly equidistant from Fargo, Sioux Falls and Minneapolis, yet somehow no one ever happens to be passing through this remote rural town
Waaaayyy too white there. And there's probably not a decent breakfast taco or pico de gallo available within a 500-mile radius. *shudders*
One interesting twist to it all is that it's an odd variant of denialism. These people aren't rejecting an established scientific conclusion, such as that HIV causes AIDS or that human activities contribute to global warming -- they are pushing beyond reason for a conclusion that science denies.
Reminds me of the freaks who insist that the Ivory Bill woodpecker still exists. Remember that garbage Science paper about the "rediscovery" back in 2005? Remember how I pointed out how crappy it was? Remember how many otherwise rational creationist-bashers bought the baloney?
http://www.pandasthumb.org/pt-archives/000986.html
Anyway, for the record: I was right.
http://tomnelson.blogspot.com/2007/08/gambling-on-ghost-bird.html
Hey, I went swimming in the Pomme de Terre. Doesn't that make me an aquatic potato? :)
@ Barn Owl (#40):
Whassamatter with you? Lutefisk is the lobster of the midwest, ya know, eh! :)
I'm quite new to learning about evolutionary theory, and just as an amateur at that. I'm reading Dennet's "Darwins Dangerous Idea" because it was $4 at the used book store an it had a positive review by Dawkins on the back, two good reasons for me.
There is a brief mention of AAT and that being my only knowledge of AAT it seemed plausible, or at least worthy of study. It sounds like the theory has been throughly trounced in the years since that book was written. Too bad, it sounded like an interesting theory, but ya gotta follow the evidence.
Not much open-mindedness on this thread. I personally think the AAH is very compelling. Here's an interesting critique of Jim Moore's website.
http://www.riverapes.com/AAH/Arguments/JimMoore/JMHome.htm
jeffox @ #42:
After growing up with family friends who are Norwegian-American, and living in England for 3 years, I think I've sampled (choked down?) every bland white boring food known to Nordic mankind, including lutefisk, lefse, mushy peas, and cauliflower jello.
Besides, in the unlikely event that I develop a hankering for Viking delicacies, there's an Ikea in Round Rock, and another in Houston. ;-)
Pickled herring pwns lutefisk any day.
The thing I question about the AA hypothesis: Why can't we close our noses?
That seems to me to be something that would be simple enough for mutations to easily produce, while also providing a significant enough advantage to any kind of aquatic ape to achieve fixation relatively quickly (ie, at least as fast if not faster than any of claimed water adaptations).
It's not that I find AAH all that compelling, it's that I do not find the savanna hypothesis compelling at all. It's the orthodoxy because it was first. That's really all it has going for it vis-a-vis AAH.
Okay, AAH is not proven, nor is it as compelling as boosters have made it out to be. It's also far from disproven, and there remains some evidence that supports the idea. It's an open question, AFAICT.
What I don't understand is why anyone's so damn het up about it. This isn't a YEC/OEC/ID type deal, or something deeply weird and totally debunked like what's-his-face's "expanding Earth" baloney; there's nothing in basic theory which either prohibits or requires hominids having gone through a semi-aquatic stage.
AAH is a minor motif which may yet turn out to be correct, or not, and won't bring down any major paradigms either way. Why all the venom?
Actually, one of the most recent common ancestor of whales and hippos is suspected to be a mesonychid, any member of a group of carnivorous ungulates from the early Cenozoic that resembled wolves with pig-like feet.
Erm - isn't there also some unsolved / not completely understood problem about humans' controlled breathing (as well as the baby's swim reflex)?
The way we speak is apparently (?) to do with our voluntary / involuntary lung control.
There was a well-documaented case of a "pet" Harbour Seal { And Seals are also "hairless animas, and have similar characteristics at birth to humans - a covering of some sort - my memory is REALLY hazy on this one ...} Ahem!
Anyway, this Harbour Seal could speak - it had learnt (by rote) from its human keepers - but it didn't sound quite right, but you could understand what it said.
I'm not saying that AA theory is correct, but there are serious unanswered questions in this field - which few people seem to be addressing.
Is there something in some parts of this hypoithesis - which is a much better name for it.
I think the deliberate rubbishing, rather than serious enquiry may be a mistake.
More opinions, please, and less rhetoric?
Humans the most aquatic ape? Sure, you betcha! Kinda obvious ain't it? See any chimps in scuba gear or surfing & swimming at the beach? We're just a bunch of tetrapodal bipedal lungfish anyway. (Thank A!) Cheese!
Pakicetids, and not Mesonychids, seem to have been the closest relatives of Cetaceans.
But my strongest argument for humanoids's aquatic phase is the Swimming Ape, described by the Scottish paleontologist and geologist Dougal Dixon in 1981. This animal is adapted to semi-aquatic life and feeds mostly on fish. Dixon's illustrated book is one of the best I ever read on evolution.
@Michael Ralston: "The thing I question about the AA hypothesis: Why can't we close our noses?"
That one's easy. We don't need to, as any swimmer can tell you. It's simple fysics, really.
Our noses are down-turned, so air doesn't flow out when we swim under water. As long as there's air trapped in your head, water won't flow in.
Of course, this doesn'r prove the AAT. But a lack of certain features doesn'r disprove it either...
Spelling! That'll teach me for not using the preview option...
I can't believe some of the crap that has been said against people who entertain the idea that we had an aquatic selective stage in our human development. We swarm to the beaches each and every year, and somehow seem built quite adequately to do so, yet to suggest AA as a hypothesis is crazy? Why the effin' hell is it crazy? Crazy is demanding aliens landing from mars, or the guiding hand of angels. It is basic Darwinian selection we are discussing here.
By the way, could people stop claiming whales came from mesonychids? The evidence has pissed all over that idea for years now. It is also not silly to say whales had a "cow-like" ancestor, as cows are probably the most familiar land animal that is related to whales. Yes, hippos are most-likely closer (both are artiodactyls), but neither resemble the actual ancestor, but at least it is more in-line with the evidence to say, "cow-like" than freakin' "mesonychid."
By the way, pointing to crazy fringe ideas some people suggest in no way harms the central premise. It is a common creationist tactic to attack fringe ideas and by doing so attempt to belittle the central premise of evolutionary theory. PZ knows this to be true, yet does not seem to stand-up against the lack of logic for using this same method against the idea we had a selective point in our past involving water.
I may not be an important person on the grand scheme of things, but I still think PZ is losing credibility with me by crowding me in with the people he has, especially when I think our semi-aquatic traits seem rather obvious...
Well. Someone didn't give Desmond Morris the memo about the diving reflex. Oh, well, outside of my bailiwick, that's why I ask questions. Though, in my defense, when I read Moore's pages, I don't find evidence of the universality of brachycardia in mammals demonstrated, but perhaps I need to dig up the references and look at them more closely.
As if (sigh) I had the time.
No, less.
I happen to speak French, and I happen to have an idea what medieval English might make of French words. I have never before encountered the English word "ballain". Most people here on this blog don't know French and won't guess what you mean.
(In French, again, it's la baleine. "Ballain" would not be pronounced the same.)
Fine.
They didn't. Whales and hippos are not ruminants, no more than pigs or camels are.
Well, the earliest whales retained small hooves on fingers II through V...
Sure. It's just unlikely that, of all animals, an ape lineage would turn to the water.
Can you form a conscious strategy on which of your features your grandchildren will inherit, and which of them will have the most children themselves?
The environment does the selection, not you.
Why don't I gain weight no matter what and how much I eat, and why don't I have webbed hands?
No longer. Both the molecular biologists and the paleontologists now ( = since December 2003) agree that, although the mesonychids are probably close relatives of Artiodactyla, whales are artiodactyls.
It has never been doubted that pakicetids are cetaceans.
Oh, so you're joking! Sorry. I didn't notice.
But since when are our noses downturned? It hasn't been long, has it?
Besides, it makes me very uncomfortable if any liquid gets just a millimeter into my nostrils, but that's just me...
The point about closable nostrils being easy to evolve is worth repeating, however. I can about half close mine: the anatomy and musculature is there, it would just have to grow a bit.
It isn't crazy. But we have the same feelings toward endless grasslands, and to thick forests...
In terms of general body shape, head shape, dentition and the like, mesonychids (especially the smaller ones) and early whales (such as pakicetids) look much, much, much more similar to each other than either does to a cow. While cows are indeed more closely related to whales than mesonychids are, they make a very bad analogue for the last common ancestor of cows and whales. Hippos, too, are a rather poor analogue. Think more of a chevrotain on lots of steroids. Google for pictures of Pakicetus, Ichthyolestes, and the like.
Hi, Jim Moore here (from a wonky Iowa rest stop connection so typing fast and many typoes). Just one point really:
It's not that I find AAH all that compelling, it's that I do not find the savanna hypothesis compelling at all.
There is no "savanna hypothesis" except in the fevered minds of AAT proponents. That is, whle human evo theories explain how we came to be able to live on savannas, as well as many other environments, they are not envionmentally determinitstic as the AAT is. Expecting a supreme environmental generalist to have gotten thatb way by means of adapting to one specific envoirnment is silly. Actuial theoprieas of human evo deal mostly with social interaction and food getting, if you actually look at the.
And for such an example, I still think my late wife's 1981 book On Becoming human (Nancy Tanner) is still very good. Feminist too, in the best way. Also a good example of biosocial anthro.
Sorry, David, since the debate derived to vertically jumping crocodiles and so, I felt I could contribute by quoting Dixon's book, which I truely love.
In general, the environment does the selection, not the animal. But the case of humans, what is environment? Parents loving more the fair and blue eyes child? The village lynching the dishonest, the depraved? We seem to be doing quite a bit of selection by ourselves. However, I dont know if it is relevant to the Aquatic Ape theory.
Regarding why you don't gain weight no matter what and how much I eat, you are very fortunate. But as a species, regarding our body fat deposits, we seem to be more like semiaquatic mammals (like pigs?) and less like chimps. On the other hand (and on this one too) we seem to have a something like looks like a kind of webbing, while chimps definitely dont.
David babbled:
"In terms of general body shape, head shape, dentition and the like, mesonychids (especially the smaller ones) and early whales (such as pakicetids) look much, much, much more similar to each other than either does to a cow. While cows are indeed more closely related to whales than mesonychids are, they make a very bad analogue for the last common ancestor of cows and whales. Hippos, too, are a rather poor analogue. Think more of a chevrotain on lots of steroids. Google for pictures of Pakicetus, Ichthyolestes, and the like."
In terms of reality, cows are closer to whales and you know it, as stated. If we say dinosaurs are "bird-like", and not "crocodile-like" you could babble about scutes and scales and teeth as well and being better analogies, but the reality is still, dinosaurs are "bird-like", not "croc-like", despite these differences.
In short, despite what we now know, you have decided to hold on to the traits that, at one time, mistakenly placed mesonychids closer to whales than embrace those traits that quite clearly shows cetaceans as artiodactlys
ALSO: I had already clearly stated that neither cattle or hippos look like the ancestor of whales in general, but stated you should not correct the person for saying "cow" or "cow-like" because anyone with half a brain knows what is being said, and using mesonychids, who are not grouped with the artio-cetacean grouping, sounds like someone having an extremely hard time getting over dead dogma.
So, Dave, spank your inner moppet, or whatever, but get over the fact that mesonychids were a freakin' mistake, and have very little to do with whale evolution at this point outside of historical mistakes.
From what we can tell from fossils, the earliest whales, the Pakicetids, would have resembled mesonychids, as both mesonychids and pakicetids have extremely similar skeletons, and extremely similar teeth. That is the basis of the idea that whales are descended from mesonychids. Whales are considered artiodactyls in that gene and protein comparisons done on mammals show that whales are related to hippopotamuses out of all other mammals. And that is the basis for the idea that whales and hippos share a common ancestor.
Current paleontological thought is that mesonychids, and artiodactyls (including whales) are descended from the same Condylarth ancestor sometime during the Paleocene period. Whether or not mesonychids were a group of artiodactyls, or whether they were simply a sister group to the artiodactyls is still in debate.
Granted, it would be easy to solve the debate with DNA comparisons, but with the mesonychids' extinction in the late Eocene, life can be cruel sometimes.
Oh, and also: even if the mesonychids and whales were on different branchs of Artiodactyla, mesonychids are still considered to be worth mentioning in whale evolution if only because the many anatomical similiarities between early, semi-terrestrial whales and mesonychids allow a tremendous amount of comparisons to be made about them, as well as to make suggestions of what ecological niches early whales may have inhabited.
Likewise, the evolutionary histories of the orders Creodonta and Carnivora are compared in a very similar manner.
"Whales are considered artiodactyls in that gene and protein comparisons done on mammals show that whales are related to hippopotamuses out of all other mammals. And that is the basis for the idea that whales and hippos share a common ancestor."
And the fact that the fossil record also shows basal whales to have the classic artiodactly style ankle joint placing them under artiodactly as well. Using teeth, which was the main traits used to support the mesonychid-cetacean connection is ALWAYS dangerous, and can be down-right dubious at times,,,
In short, the genetics, as well as the fossil record now shows them to be clearly artiodactyls, and mesonychids are not only not artiodactlys, they are not even a singular grouping. They are more of a bag of similar looking predators that are not an actual monophyletic group (at least no one has shown them to be so).
@ Barn Owl (#45 above):
Ya ya, I hear you there. And I have to thank you for your entry, it isn't every day that I get the opportunity to make a lutefisk joke. :)
Which reminds me of another joke: Minnesota only has 2 seasons, one called "cold" and the other called "bugs". :)
That reminds me, I need to get to work on my paper on how the Savannah Hypothesis explains why humans like going to the park on a sunny day.
We are going to the beach with the children. I know we shouldn't. The crocodiles. The sharks.
Back at another internet connection:
But then to declare that human hairlessness should be "obviously" due to sexual selection?
The thing is that human hair patterns show the classic signs of sexual selection, to the extent that if one wants to come up with a non-sexual selection reason, one has to include why the result exactly mimics sexual selection. Now we know that hair varies really easily, and quickly in evolutionary terms. Even looking just at our own species tells us that, and we know that the diffs we see in hair are caused by very little genetic change. In dogs, I believe, just one gene controls all the variation seen in dogs.
But the bottom line is that in humans, if it isn't sexual selection, it's something that exactly mimics sexual selection.
The fellow (jamie, I think) who mentions aquatic predators steps into a problem that is very common. We have changed the sitaution for predation since prehistoric times. We have decimated predator populations, and the bigger problem is that no population on earth does the time in the water that the AAT requires to get the characteristics they say we have. Leaving aside the fact that they describe these charactoristics inaccurately and that their claims fall apart on that alone, they are talking about convergent evolution giving us the charactristics of whales, serenia, and seals. That doesn't happen by someone spending even several hours a days in water, or just some members of the population. There is no human population anywhwere (and never has as far as I've ever heard, that approaches what you'd need for whales, serenia, or seallike convergent evolution. Which is why AAT proponents are typically very coy about not naming the creatures they're comparing us to.
Humans as a species are the most aquatic ape.
[Compare Homo sapiens to Hylobatidae, Gorilla, Pan, Pongo]
Sexual selection IS natural selection, except for asexual reproducers (bacteria, some parthenogenic komodos, etc.). So "sexual selection" has no explanatory value except in comparison to asexual reproducers.
I don't know why the term was brought up, since apes reproduce sexually. But only humans swim, dive, carry water containers, even use it to dispose of their waste.
I don't know if it's worth the bother to classify it as a theory though, kind like claiming an Aquatic Artiodactyl Theory regarding whales despite the fact that many whale fossils have been found in deserts and even in wine grape orchards.
1.2 MYA may be too much for clothing or shelter, but not for fire. In fact, one could make the argument that all species which go near fire are hairless or at least thin haired, rhinos and humans are both quite bare. And there isn't convoluted logic to make the connection rather hairy people burn.
Argh! I don't dispute that some human hair PATTERNS are probably due to sexual selection, but I haven't seen an explanation for why humans needed to LOSE their fur almost completely to make patterns with the little that was left? A trait that is present in both sexes from birth does not "exactly mimic sexual selection"!
For example, a peacock's tail patterns are due to sexual selection, but the presence of a tail in both sexes is not! But that may be a bad example since it's easy to explain why peacocks have tails. How about: reindeer are the only species where a female has antlers. There are differences in the female and male antlers. That does not mean that the trait of females having antlers in the first place can be attributed to sexual selection.
Yes. I think Wrangham's hypothesis of early cooking is intriguing; it would also explain why hominid teeth and jaws show a switch to softer foods around that time.
http://www.sciencedaily.com/releases/1999/08/990810064914.htm
But besides the lack of evidence for widespread use of fire that early, I wonder: if fire has been the center of human life for over a million years, why haven't humans developed some sort of "firemaking instinct" via the Baldwin effect. Perhaps all-purpose brains do the trick just as easily.
I am one of AAT proponents, active on the Internet. I discuss AAT idea for few years, now. Have been involved in discussion with Jm Moore, as well.
Regarding noses, take a look at Proboscis monkey (females). How many million years have Proboscis monkeys those noses? Is this seen looking at the skull?
Whoever claims that he isn't fat, he should take his picture when he was a baby, and take a look at a baby ape.
For sharks, anything that doesn't have odor on fish isn't a food (just like sashimi isn't food for my niece, : )).
If you search for one animal which could show you what happens with fur in a sea water environment, take a look at marine otter. Other otters go to sea from time to time, but they need to have a pool of fresh water nearby, to wash out salt crystals. Sea otter is non-stop wet.
I even took one of Jim Moore's arguments to argue against our aquatic phase being in shallow waters. The argument is that cats leap well through shallow water.
My sceanario happens at rocky coast. This is nice, climable environmnet, with a lot of meat, readily avaible for someone who can pick it up with its fingers (like racoons and monkeys/apes). It is really shameful that paleoanthropology doesn't take AAT more seriously, it has to "explore all the possibilities".
It is interesting that I am also a "savanna" proponent. Not only that I am claiming that people lived in savanna, I am even claiming that people created savanna (by the use of fire). Another thing that I am claiming is that humans don't have superior intelligence. Humans have big heads solely for thermoregulation (Homo floresiensis is nice example).
Also, I wouldn't be surpised if we lived amongst and with cattle for all that time (and not being mighty hunters - no, I am not a feminist, : )).
PZ is up in Morris, MN, which is just to the left of the big "C" of lakes that make up the majority of the "Land of 10,000+ lakes". Morris happens to be on a railroad line and at the intersection of a bunch of highways, so there's plenty of traffic, otherwise it'd be just another farm town (with a fabulous university).
Before the days of the locomotive and wheeled vehicles, and before the bow and arrow and atlatl were developed, and before horses were domesticated, humans could travel by foot or by dugout. Dugouts provided relatively safe access to remote inland areas where the big cats were kings and crocs and hippos resided. Before the development of the dugout, the most successful inland hominids were those that could climb above the cats and crocs, which is why the inland apiths had curved phallanges and ancient Homo didn't. Dugouts allowed easy access to extra weapons including slingstone pebbles used as ballast and spears used as push-poles, heavy cumbersome tools to carry by foot but easily by boat. Travel and trade eventually expanded from coastal settlements inland. Before dugouts, the inland was a dangerous place for a hominid that couldn't climb well or run fast and had only thrusting spears IMO.
Dugouts, originally crafted by butted handaxes from waterside bent hollow tree trunks, were the first pickup trucks, and are still used worldwide in a more engineered form. A fisherman in one caught a coelecanth off the beach in Sulawesi in May. Ribbed watercraft (birchbark canoes, plank boats, umiaks) came later, partly due to the need for portaging.
Dugouts were the transitional technology enabling a coastal hominid to move upstream and inland, changing from daily diving and plucking sessile seafoods (where hydrodynamics were significant) to more terrestrial hunting and "dry" fishing using nets and spears. IMO.
IT must be noted that Mario Petrinovich has also stated that penguins are fish, and that North America has no savannas (and that pronghorn antelope live in the mountains). Amongst other things. :)
Lol, a fine example of Jim Moore's arguments. Of course that I know that penguins are birds, but I probably talked about their morphology, or something. Now Jim Moore will make a web site about me, saying that I am claiming that penguins are fish. Lol. Those kind of arguments Jim Moore also uses against AAT. It is funny how uninformed people get a wrong view about AAT reading Jim Moore's pages. But hey, its up to them and their own intelligence to figure out what is what.
I still remember how some people at s.a.p. (sci.anthropology.paleo) chalenged everyone to despute some claim that Jim Moore wrote on his site. I took a look, and it was so easy, it is unbelievable. I called that article pure garbage, which is what it was. Instead of mentioning any arguments, this article simply spat on Elaine Morgan as a person. Which is really interesting, because everybody who spoke a single word with Elaine has very high opinion of her. As someone who has very low scientifical knowlage, I desputet that article with EASE. Lol, just like that. Peace of cake.
Regarding pronghorns. I am claiming that America doesn't have savanna ecology. Well, I don't know very much about America's ecology, but nobody managed to despute that claim of poor me. Somebody, some knowlagable American (was it Jim Moore?) mentioned pronghors. It was almost the first time that I've heard about those animals (later I remembered that I saw them in one documentary). But, it was easy case for me. Pronghorns don't even eat grass. Lol, what a fine savanna animal, that even doesn't eat grass. Pronghor eat herbs. Yes pronghorn lives in preire, but also in Nevada. It is known how fast pronghorns are. This is because they have excellent absorbtion of oxygene. Yes, they are animals of Nevada highland, not animals of preire. They live in preire only because they are fast, and this is open country, and safe for them, regarding predators. Not because they are savanna animals, and evolved in savanna, surrounded by grass.
So, dear knowlegable people, it is so easy to deal with you. And yes, I am claiming that savanna ecology is only present in the Old World, world where humans lived. Actually, just recently they discovered 30my old savanna ecology in Chile. It is a region with strong presence of fire (volcanic region), and that fire was present for extremly long time, there. Yes, fire is what makes savanna. HUMAN's fire.
I'll let this be the last of my posts in this comment thread, but a couple points.
One is that I don't write on my site, except in passing, about anyone other than the principle proponents of the AAT, and I write about their basic, main claims, contrary to one of the earlier comments here (and contradicting Mario's hope above :).
The other is that while Mario again tries to sound reasonable here, when the subject of pronghorns came up (not from me) it was in response to the sort of silliness he was writing nonsense such as this: "Then, didn't you notice that there aren't grassland fauna in New World?" After pronghorns came up he claimed they didn't eat grass, didn't live on the plains, and so on. And this is actually some of the least silly stuff he writes.
Sadly, the stuff from the AAT principles isn't all that much better.
In South America, the most important savanna animals are ANTS. This is why we have anteaters, there. The SAME thing happened in the Old World 8mya, when aardwark spreaded. In North America the most important savanna animals are ground squirrels called preire dogs. So, on one hand we have ants, on the other hand we have squirrels, as SAVANNA animals. Now, compare this to savanna of the Old World.
People thought for a long time that ariditation trend from the past, was global. As far as I know, and the newest reaserach show this, it WASN'T global.
So, I definitelly can see that I CANNOT REASON Jim Moore. I was perfectly clear in presenting my idea. He calls my idea silly, just as he calls AAT idea silly, but that's about it. If some idea is called silly by Jim Moore, then you people should listen to him, and not bother too much with that idea.
If AAH is true, why are there still MERMAIDS & SIRENS?!?!
I see you don't know very much about AAT. I don't know very much about soccer, so I stay quiet when people talk about soccer. -- Mario Petrinovich
As far as the A.A.T. discussion is concerned; look at live humans and what they can do and like to do. It is not so daft to tinker with the idea of a more aquatic past for mankind. Yust open your eyes and don't pretend to be absolutly sure about the information from old, distorted bones and long lost and shattered habitats. Modern day properties can be researched and the outcomes eventually falsified, something that is impossible where fossilized bones are concerned.
Do the same as my students...(follow provided link)
Dirk Meijers
Biologist
Hippopotamuses are almost as bad, big and mean, people avoid them.
"Almost"? Apart from usually being heavier, they'll kill you for trespassing. Crocodiles only bite you when they're hungry. Lots more people die from hippo attacks every year than from croc attacks.
But that's not where we come from!
Far fewer than "hundreds".
The what? La baleine? "The whale"? Firstly, dolphins are whales, more closely related to the sperm whales and the beaked whales than the baleen whales are. Secondly, whales as a whole are even-toed ungulates, and their closest known relatives are the hippos, though the most recent common ancestor of these two groups must have looked more like a duiker. No really cow-like animals are involved, and no carnivorans.
The chimpanzees live north of the Congo, and the bonobos south of it. The (admittedly big) river is all that separates them. Gorillas and orang-utans, too, don't swim.
But that's not how evolution works! A species can only become more aquatic if the best swimmers have the most surviving fertile offspring, and if swimming ability is inheritable. Wanting it doesn't make it so.
I doubt the situation is as black and white as that. Most animals can swim if they are forced to.
Btw, I would like to see some reliable data on this. The web is divided. As Jim Moore himself notes:
And there are more discussions like that on other web sites, but not so much data.
Also, groups of monkeys and apes may for one reason or other seek to water. Beside the japanese monkeys, IIRC Attenborough had some shooting of a group of gorillas who regularly feed half submerged in swamps.
Humans may be unique in some respects, but not in our ability to take to water. Which would be another mistake behind the AA idea.
Oops. I forgot to add that humans may drown when they fall into the water as well. We need to learn how to swim passably in most cases.
Maybe I don't understand the question, but Jim Moore discusses this too. Seems it is a shared, possibly ancestral, trait among vertebrates. (Snakes, rabbits, dogs, armadillos, ...) And, oh joy, this time there are references.
No, less.
I happen to speak French, and I happen to have an idea what medieval English might make of French words. I have never before encountered the English word "ballain". Most people here on this blog don't know French and won't guess what you mean.
(In French, again, it's la baleine. "Ballain" would not be pronounced the same.)
Fine.
They didn't. Whales and hippos are not ruminants, no more than pigs or camels are.
Well, the earliest whales retained small hooves on fingers II through V...
Sure. It's just unlikely that, of all animals, an ape lineage would turn to the water.
Can you form a conscious strategy on which of your features your grandchildren will inherit, and which of them will have the most children themselves?
The environment does the selection, not you.
Why don't I gain weight no matter what and how much I eat, and why don't I have webbed hands?
No longer. Both the molecular biologists and the paleontologists now ( = since December 2003) agree that, although the mesonychids are probably close relatives of Artiodactyla, whales are artiodactyls.
It has never been doubted that pakicetids are cetaceans.
Oh, so you're joking! Sorry. I didn't notice.
But since when are our noses downturned? It hasn't been long, has it?
Besides, it makes me very uncomfortable if any liquid gets just a millimeter into my nostrils, but that's just me...
The point about closable nostrils being easy to evolve is worth repeating, however. I can about half close mine: the anatomy and musculature is there, it would just have to grow a bit.
It isn't crazy. But we have the same feelings toward endless grasslands, and to thick forests...
In terms of general body shape, head shape, dentition and the like, mesonychids (especially the smaller ones) and early whales (such as pakicetids) look much, much, much more similar to each other than either does to a cow. While cows are indeed more closely related to whales than mesonychids are, they make a very bad analogue for the last common ancestor of cows and whales. Hippos, too, are a rather poor analogue. Think more of a chevrotain on lots of steroids. Google for pictures of Pakicetus, Ichthyolestes, and the like.
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