Sea Monkeys

Quite a few years ago I ran across a book – I can’t recall where – called The Descent of Woman, by Elaine Morgan. Published in 1972, it puts forward a most unusual idea about human evolution, and it’s worth a mention here. I’m curious to know if any of you are familiar with it.

I think that Morgan, a Welsh feminist writer, wrote the book as a response to what she saw as an androcentric bias in Desmond Morris’s The Naked Ape. But the book attracted more attention for its defense of an idea that had been knocking about for about thirty years at the time: the “aquatic ape” theory, which says that the ancestors of modern humans spent a critical period of their evolutionary history living in the water.

Morgan adduces an impressive list of observations to buttress the claim. Here are a few:

  • Of almost two hundred species of monkeys and apes, every one but us is covered with hair. Aquatic mammals, however, tend to be hairless.
  • The voluntary control that humans have over their breathing is apparently unusual among mammals, again with the exception of those that live in the water. This voluntary control of the breath, Morgan argues, was a necessary precursor to the complexities of human language.
  • Humans further resemble aquatic mammals in their distribution and retention of body fat. Also, central body fat in humans is not attached to the muscles, as in most land mammals, but to the skin, as in aquatic mammals.
  • Humans are the only mammals that are capable of truly upright bipedal locomotion, and Morgan suggests that the transition occurred during the period that our body weight was being supported by water. Monkeys and gorillas walk upright when wading.
  • Human babies at birth are covered in the waterproof and waxy substance vernix, a trait we share with seals.

Morgan was not trained as an anthropologist, and her book was greeted with scorn and derision from the professional community. Shortly after reading the book, which I have to say I found quite persuasive, I had an opportunity to mention it to Stephen Jay Gould, who said, with a contemptuous snort, “Oh no – not that awful book!” When I replied that it seemed to me to make quite a few cogent arguments, he pointed out one serious objection to the theory, namely that mammals that become aquatic quickly lose leg strength and size, whereas humans have very large and powerful legs.

But despite never gaining much acceptance among anthropologists, the idea has never really gone away, either, and is still controversial. You can read more about it here, and here.

One recollection that has just swum into mind (I can’t recall for certain if it came from this book – actually I think it might not have, but now that I’ve thought of it, it’s interesting enough to mention) is an explanation of why the hair on our bodies is arranged in the way it is. For example, the hair on our legs points down, toward our feet, but the hair on our forearms and the backs of our hands tends to lie pointing up the arm, away from our fingers. The suggestion I recall being given was to imagine a naked human covering himself in a rainstorm, seated on the ground in the most abject position. With knees drawn up, elbows together, hands upon the head, and the head tilted forward, all the hair, from the crown of the head on down, is aligned earthward.

Elaine Morgan has, in later years, taken aim at what she considers “right-wing” science, as exemplified by Pinker, Dawkins, et al. In fact her newest book is called Pinker’s List, and is a direct response to The Blank Slate.

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  1. Bob Koepp says

    The aquatic ape theory is, I think, most valuable for prodding evolutionary thinkers to carefully consider what kinds of evidence might help us to pick and choose between competing “just so stories” about origins. Given the shakiness of some of Gould’s own speculations about the course of macro-evolution, I find his reaction to Morgan’s idea a bit disingenuous. One observation here or there isn’t likely to be determinative in a science that works from consilience.

    Also, I wasn’t aware that polar bears have smaller or weaker legs than than their more terrestrial relatives…

    Posted February 15, 2006 at 9:18 am | Permalink
  2. Andrew says


    The hair on my arms points towards my hands…

    Posted February 15, 2006 at 10:21 am | Permalink
  3. Malcolm says

    Hi Bob,

    I was a bit surprised too by the vehemence of Gould’s reaction. The level of acrimony in the academic professions is quite startling sometimes. I suppose that in his opinion the theory was obviously rubbish, and he was tired of hearing about it.

    True, polar bears have good strong legs. But they are not exclusively, or even primarily, aquatic. I imagine Gould had in mind pinnipeds, cetaceans, and the like.

    Mind you, I am not taking a stand here in favor of AAT; I mentioned it because I thought some readers might not have been familiar with it. Right or wrong, it is an interesting idea, and illustrates, as you point out, the need to be as broadminded as possible when attempting to reconstruct evolutionary history. Life does indeed take some startlingly strange turns, even if it didn’t take this one.

    Andrew, you might want to get that looked at.

    Posted February 15, 2006 at 10:39 am | Permalink
  4. Robert says

    Malcolm, I read the book in the early 90s (I had previously read The Naked Ape) and found it quite thought-provoking, at any rate. It’s also interesting what you say about Dr. Gould’s response to a mention of it; I recall reading one of his columns where he discussed whether evolution had a purpose, and he not only dismissed the idea, he did it with such vehemence that it was bizarre. It struck me that it was as if there was a purpose, his whole weltanschuung would be refuted, and the next thing he knew he’d have to go to church or something. Anyway, I enjoyed reading him, but you actually met him, so perhaps you know more about this than me…

    Posted February 15, 2006 at 2:54 pm | Permalink