For the past ten years, I've been looking at the evidence given for the aquatic ape theory to determine whether it's accurate, honest, and makes sense in terms of evolutionary theory. Sadly, it fails badly.
I've been doing this checking for 10 years now and have had a version of my site up since 1996. My site has been used as a reference by The Straight Dope (22 Jan 2002) http://www.straightdope.com/mailbag/maquaticape.html
and The Fortean Times (Oct 2003), as well as the Talk Origins Archive and several college courses.
The site is Aquatic Ape Theory: Sink or Swim? http://www.aquaticape.org
A few notes on what you've quoted (unfortunately, you've been misled about the facts); I have quite a lot more on my site: Humans may have once been semi-aquatic. here is some stuff to go with this theory:
- humans are the only primate that takes pleasure in swimming
Must we be able to prove they"take pleasure" in swimming? How about primates who are simply very good at swimming and do so regularly? In that case, there are several, and they dive too, and no, they are not mostly bipedal as "aquatic ape" proponents often claim. - humans have fat attached under the skin like aquatic animals. mammals which hibernate have seasonal fat: aquatic mammals, similar to huimans retain fat yearly.
This is a complicated mashup of wrong "facts". Human fat, like the fat of all mammals, is attached to internal depots -- we have a wide range of fattiness in humans (from around 2-5% to over 75%) and our fat characterisitics -- both amounts and where you find them, are similar to other primates which are overfed in captivity. All fat is seasonal; it's a food source which gets laid on in good times and used up in bad times, for humans as well as all other animals, including aquatic mammals. There's a lot more about fat on my site. - humans hair does not cover most of the entire body. The only environments known to give rise to naked are aquatic and subterranean
Actually human hair covers most of the body, but much of the hair on the body is short and generally thin. The claim that "the only environments..." is a way that aquatic ape proponents dishonestly try to make a statement without saying just what mammals they are comparing us to, because they really don't like pointing out that they are comparing us to whales and serenia (dugongs and manatees), which are highly specialized aquatic mammals which have been fully aquatic for many tens of millions of years, which cannot live outside water, and which, like seals, have highly specialized skin which is very different than ours. - human young are born alive except for the small subclass of monotremes and nourished with milk
True of all mammals except montremes; and even they nourish their young with milk. However, there are differences between aquatic and terrestrial mammals in this, and especially between aquatic mammals and humans. Aquatic mammals are born rather advanced as opposed to humans, and they have milk which is very different than humans milk in several features (extremely rich in fat and protein, and very low in lactose). - we are only ape that walks fulltime in a bipedal posture. water supports the body
First part true, more or less (pretty much fulltime, anyway); the second is a non sequitor really. Variations of this argument have been used by aa proponents, and then when you (I actually) point out the problems with this idea they fairly scream out that they were never suggesting that we were in water deep enough to support us... then they go on talking about water and support. I think they're a bit confused on their strategy on that point. -the voluntary control of breathing in humans is similar to aquatic mammals which inhale as much air as they need for a dive, then return to the surface for air
Radical differences. First, the voluntary breath control of humans is present to a greater degree than in mammals which are quadrupedal, since a side benefit of bipedalism is exactly that freedom in breathing because the forelimbs aren't being used in locomotion. The statement about aquatic mammals here is possibly true, but I haven't seen it shown to be true -- Elaine Morgan claimed this (ignoring the fact that aquatic mammals such as seals and whales actually exhale before diving, collapsing their lungs -- the oxygen for their dives is held in their blood, which is radically different than ours). When Morgan made this claim she used a ref about bradycardia (the slowing of the heart rate) erroneously thinking it was about breathholding.
BTW, untrained dogs can hold their breath somewhat longer than can untrained humans -- the fact that they can do it at all shows the statement to be false; the fact that they actually do better than we do at breathholding shows we aren't all that good at it. new born human babies can hold their breathes in water
The "swimming babies" features are common to all mammalian infants tested, terrestrial and aquatic. And although the statement you made has been made for years now (and has been corrected, at least by me, for over a decade) the original paper that found this fact also mentioned very clearly that this is not something unique to humans or to aquatic mammals. - human hair is streamlined like aquatic animals
This is the "hair tracts" idea, and it's nonsense. First, when you're making this statement, ignore curly hair on the body, like the hair you find on many many people; also ignore the hair on your shoulders, which for many people goes every which way. And then tell me just what swimming position goes along with this idea, because if you're honest you'll be forced to admit that this requires swimming in a prone position, with the crown of the head pointing forward (not looking where you're going) and with the arms held straight down along the sides. I've had people claim that "some variation of the breaststroke" would do it, one where the entire head and beard is held out of the water and with the arms held along the sides. Really now -- next time you're at a pool try swimming in that position. - amino acids found in seafood is also found in humans
Confused statement. This is an attempt at a statement about DHA in the diet (not to be confused with DHEA). DHA is needed for brain growth and is present in fish, but it's also available in wild game, and can be synthesized (except by infants, who get it through breast milk) from LNA, which is available in a great many plants. - humans can't survive without water for a limited time (we are the most water dependent animal)
The statement that we are the most water dependent animal is nonsense, even if you lop off all aqautic and semi-aquatic animals. - humans are the only terrestrial animals that cry and produce tears. the removal of excess salts from the body including tears and sweating (similar to marine animals)
We are not the only animals who produce tears, but we are the only animal which is proven to produce emotional tears. All animals produce basal tears which keep the eye lubricated. When it comes to emotional tears, there are anecdotes of various animals, both aquatic and terrestrial, producing them, but no proof. One interesting aspect of this claim is that it originates with Morgan and she got her info from a good book on the subject but, when it came to making her list, she listed all the anecdotes about aquatic animals and ignored all the ones about terrestrial animals, which means she either did so dishonestly or merely inadvertently skipped every other paragraph. Tears and sweat are not vectors for removing salt from the body -- you lose some, but you always lose more water in doing so, and the whole process is unregulated. This is critical, since adjustment of the salt/water balance is critically important (doing it wrong leaves one weak, cramping, and soon violently ill and eventually dead). In all mammals, the avenue of maintaining the salt/water balance and getting rid of excess salts is via the kidneys. In actual marine mammals the kidneys are large and heavily lobulated, unlike those in humans and other terrestrial mammals (except for desert animals such as kangaroo mice, which face the same problem that marine mammals face -- lack of fresh water).
In fact, this particular bit of "evidence" is so over that even aquatic apedom's reigning queen, Elaine Morgan, has disavowed it -- although at the same time she tries to have her cake after eating it. What are your thoughts?
See my web site for more.