Relevant Questions for the Aquatic Ape Theory

The AAT/H relies heavily on the principle of convergent evolution. According to the AAT/H, convergent evolution produced massive changes to our body structure (ie. bipedalism) and systems in very little time -- producing, among other things, a salt excretion system like those seen in crocodiles and sea birds, rather than the one used by marine mammals.

In fact, the AAT/H is so dependent on the principle of convergent evolution that it uses it to make statements which ignore the crucial role of phylogeny (relatedness) in evolution. For instance, the AAT/H says we did not evolve on land because some of our adaptations, such as our method of thermoregulation, are different from the methods used by other distantly-related-to-us mammals in that habitat, such as "the wild ass and the camel". This ignores the fact that an organism can't just evolve whatever is handy, picking it from some sort of evolution catalog of desirable features, and it ignores the fact that in any given environment, the creatures who face common problems often evolve different solutions to the problem.

Convergent or parallel evolution does operate, though, and can be demonstrated when you see different organisms evolving common solutions to shared problems. This is common in aquatic species; however -- ironically -- the AAT/H consistently ignores the many actual examples of convergent evolution in action in aquatic and/or marine animals.

Therefore, these questions -- the first 5 are about traits which actually are aquatic and/or marine characteristics and which are ubiquitous and due to convergent or parallel evolution -- come to mind.


These are five real aquatic traits, traits shared by virtually all aquatic mammals, even those which are not closely related. Why don't humans exhibit these actual aquatic adaptations?

1.  Why don't humans have really small ears (or no external ears) like virtually all aquatic mammals?


2.  Aquatic mammals have shorter legs, or no legs, relative to land-based animals, including their land-based relatives. Early hominids had legs similar in length to our relatives. According to the AAT/H, there was enormous selection pressures that produced massive changes to our skeletons for an aquatic life, and according to the AAT/H, this was due to convergent evolution. Why were our legs, unlike those of other aquatic animals, exempt from convergent evolution?


3. Humans have young that are born less developed than our relatives, and they develop more slowly as well. Aquatic mammals have young that are quite advanced compared to similar terrestrial mammals, including their terrestrial relatives (for example, seals as opposed to land-based carnivores), or which grow very quickly, or both. Why did the purported aquatic hominids change in the opposite direction from other aquatic mammals?


4.  All marine mammals produce milk that is extremely rich in fat and protein, and very low in lactose (milk sugar). It ranges from a low of 20-25% fat for sea otters to 30-60% for pinnipeds and whales; protein ranges from 5-15% or more; lactose is virtually non-existent. By contrast, human milk and cow's milk are about 2-4% fat and 1-3% protein; lactose in the milk of terrestrial mammals is typically 3-5%. The lactose content of human milk is as high as 6-8 percent. Why are humans so unlike all marine mammals and so like terrestrial mammals?


5.  One AAT/H claim is that we evolved in saltwater and therefore adapted in the same manner as aquatic animals, with convergent evolution supposedly evolving a salt excretion system like that seen in sea birds and crocodiles (and many terrestrial reptiles and birds). Why didn't we adapt as all marine mammals have done, via a change to our pre-adapted kidneys -- which are the regulated salt excretion system used by all mammals -- developing better hormonal control over rate of urine formation and concentration via the kidneys, as has repeatedly happened, due to convergent and/or parallel evolution, in cetaceans, pinnipeds, and sea otters?


A common answer I've gotten to these questions -- in fact the only answer I've gotten to these questions -- is that "there wasn't time". However, according to the AAT/H, there was enough time to cause massive changes in our physiology, some in ways not seen in any other mammal. There was supposedly enough time to change not only our pelvis, but also to change our salt excretion system into systems that resemble those in sea birds and reptiles (but completely unlike any mammal, terrestrial or aquatic), to change our sebaceous glands into seal-like features, and other such incredible leaps. Yet somehow there just wasn't quite enough time to cause those very changes we see in virtually all aquatic mammals?

This AAT/H response is special pleading of the first order.


Some additional relevant questions for AAT/H proponents

6.  Some AAT/H proponents say our pattern of hair orientation is due to water flow while swimming. This requires that a great deal of time be spent swimming with the crown of our heads forward and our arms held along our sides, pointing toward our feet.  In her latest book, Elaine Morgan also suggests we simply held our heads out of the water while doing this, making for an even more improbable swimming position. Some questions:

A. How did we swim in this position?
B. How did we breathe while swimming in this position?
C. Why didn't we look where we were going?
D. The reduction of hair and its orientation has been said to be an adaptation for speed in the water; how did we swim fast in this position?
E. The reduction of hair and its orientation has been said to be an adaptation for speed in the water to escape sharks (Hardy 1977, reprinted 1982); but while large land-based predators run approximately 3-4 times as fast as humans, sharks swim approximately 3-6 times as fast as the fastest Olympic swimmers. Why were we able to swim away from sharks but not run away from land-based predators?


7.  We know that our close relatives, chimpanzees, survive in spite of large terrestrial predators in open savannah woodland (and in fact apparently do so more ably than their forest cousins), and we have observations of them in the wild that show us how they do so. How did the postulated aquatic transitional population deal with common aquatic predators such as crocodiles and sharks?


8.  Hardy and others say that during this supposed aquatic phase of the transition, we learned to make sharpened stone tools, knives, and even spears, and to hunt and butcher large animals: why did we quit doing these extremely useful things for the next 4-6 million years after supposedly learning to do so?


9.  Elaine Morgan claims that the evidence of vitamin A poisoning seen in the Homo erectus specimen KNM-ER-1808 was from eating fish -- rather than from eating carnivore liver, the generally accepted likely cause (carnivore liver stores vitamin A in often-toxic levels) -- and that this shows we had been doing so since the transition from apes (i.e., for 4-6 million years). If so, why hadn't we either:

A) developed a resistance to such toxic reactions to a food which supposedly had been eaten regularly for approximately 4-6 million years before that time?
B) learned, in that 4-6 million years, how to avoid toxic poisoning from a supposedly common food?
C) if we had developed such a resistance and continued those habits, why did we lose this adaptation?


10.  Marc Verhaegen makes a similar claim that a pathological condition (which we might reasonably expect to see weeded out of an aquatic population) is actually evidence for some degree of aquaticness. These are exostoses in the ear canal, bony growths that he says only occur after a great deal of time (he usually says years) either swimming or diving. They are seen in a small number of Neanderthal and Homo erectus fossils. He calls them "undeniable indications of frequent diving" (sometimes he says swimming) and says that they must have been wading and diving because "Their ear exostoses leave no other choice..." (ellipses in original -- links to these posts are in the references). But ear canal exostoses actually can be due to almost any irritation, most commonly either cold air or cold water. They are not due only to cold water, as he repeatedly claims, and this is widely known and readily available in medical texts (he is a medical doctor). Even online medical sources mention this:

"Exostoses occur when the external canal is repeatedly exposed to cold air or water."
"Geriatric hearing loss: Understanding the causes and providing appropriate treatment" by Michelle C. Marcincuk, MD and Peter S. Roland, MD

"Exostoses are bone growths that often develop when the ear canal is repeatedly exposed to cold water or cold air."
Yale New Haven Health Library

"The exciting cause of ear exostoses, where the predisposition to these exists, may be anything mechanical or chemical that produces prolonged irritation, with consequent hyperaemia to inflammation of any part of the bony meatus."
Ales Hrdlicka quoted in Dry Bones, Chapter 4."

The obvious question here is how can a medical doctor be ignorant of the medical literature on such a well-known ailment about which accurate information is so readily available?


Recap: Actual ubiquitous convergent features of aquatic mammals:

  1. Smaller ears (or no external ears) than their non-aquatic relatives.
  2. Shorter legs, or no legs, compared to their land-based relatives. (Early hominids had legs similar in length to our relatives.)
  3. Aquatic mammals have young that are quite advanced compared to their terrestrial relatives (for example, seals as opposed to land-based carnivores), or which grow very quickly, or both. (Humans have young that are born less developed than our relatives, and they develop more slowly as well.)
  4. All marine mammals produce milk that is extremely rich in fat and protein, and very low in lactose (milk sugar). It ranges from a low of 20-25% fat for sea otters to 30-60% for pinnipeds and whales; protein ranges from 5-15% or more; lactose is virtually non-existent. (By contrast, human milk and cow's milk are about 2-4% fat and 1-3% protein; lactose in the milk of terrestrial mammals is typically 3-5%. The lactose content of human milk is as high as 6-8 percent.)
  5. Marine mammals have extremely large and/or extremely lobulated kidneys (due to convergent and/or parallel evolution).
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