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KRONOS Vol IX, No. 2
The Paradoxical Primate
A Review of
The Aquatic Ape: A Theory of Human Evolution by Elaine Morgan
Stein and Day, New York, 1982, 170 pp., illustrations; $14.95.
ROGER W. WESCOTT
Ever since Linnaeus took the radical step of classifying human beings as members of the same zoological order as apes, monkeys and lemurs, taxonomists have been puzzled as to how best to subclassify our species. Are we overgrown lemurs, upright monkeys, or hairless apes?
Following the death of the eminent British primatologist Frederic Wood Jones, a consensus developed that man is (broadly speaking) a hairless ape, belonging to the same hominoid superfamily to which gorillas, chimpanzees, orang-utans, and gibbons also belong. But this did not end the puzzle. For, if apes at all, we are anomalous apes, deviant with regard to more than hairlessness.
The hominoid superfamily is customarily divided into two families the hominids, including contemporary man and his immediate fossil forebears, and the pongids, including all the (other) apes. Among the unpongid characteristics of our species are those listed in the accompanying chart.
As the diagram below suggests, our unapelike characteristics cluster in certain areas. Of these, the most conspicuous is probably the one that is related to our mode of locomotion, unique in the primate order. While most of our nearest kinsmen are either two-armed brachiators like the gibbon or four-limbed knuckle-walkers like the gorilla, we stand, walk, and run upright. And our legs are longer than our arms quite the reverse of the proportions encountered among such fellow hominoids as the chimpanzee or the orang-utan.
UNPONGID HOMINID TRAITS
The next most conspicuous human characteristics that separate our species from the pongids cluster in the area of skin-covering. Where the apes have fur, we are bare-skinned - except in the region of the scalp, underarms, and genitals, where we have more hair than they do. Among some races, our adult males lose their head-hair; while among all races, pregnant women experience a thickening of their head-hair. Most peoples compensate for the scarcity of their natural skincovering by clothing themselves with organic materials drawn from other species.
Another cluster of distinctively human traits has to do with the protrusiveness of our erogenous zones. We are the only primates with large busts and buttocks, and our penises and vaginas are longer than those of any of the apes. We are the only primates whose coitus is usually ventral rather than dorsal, and we seem to be the only primates who experience orgasm (as distinct from, and supplementary to, ejaculation) .
A fourth trait-cluster has to do with the shape of our faces and the function of related diaphragmatic organs. Our noses and chins protrude, while our teeth are reduced both in length and in grinding surface. Among other primates, only the proboscis monkey of Borneo is our equal in nasal prominence. Among the hominoids, we are unique in having voluntary muscle control of our nostrils, of breathing and of vocalization. No other primates weep or suffer from asthma. And our insensitivity to odors exceeds that even of the great apes. We are as anosmic as birds!
Above the eyes, our heads bulge. Our bulbous crania are necessitated, of course, by our outsized brains, which are about three times as large as those of the great apes. The only animals whose brains are larger than ours in an absolute sense are whales and elephants; and the only animals whose brains are larger than ours in a relative sense -that is, in proportion to overall body size - are some of the smaller bats and tailed monkeys. (Whether such "civilized" behavior patterns as our literacy, urbanism, and electronic technology should be directly linked to our cranial capacities is an open question. The fact that whales and elephants lack those refinements can be explained either by denying the link or by noting their lack of manual-digital prehensility.)
Mention of prehensility leads inescapably to consideration of the human hand. Structurally and functionally, it is not very different from the hand of the gorilla or the chimpanzee. Its chief anatomical divergence from theirs lies in the webbing between the human thumb and forefinger, which prevents most of us from touching the wrist of either arm with the thumb of the same arm. This loss of flexibility, however, is largely offset by the fact that our finger-tip sensitivity exceeds theirs, even on the thumb. Here, too, as in the case of the brain, it is uncertain to what extent we can attribute our technical proficiency directly to our manual dexterity. It is now clear that wild chimpanzees, for example, not only use tools (as do otters, finches, and even some invertebrates) but also make tools. Their most impressive manufacture is probably the poke-stick for fishing termites out of logs or mounds, a tool which they create by stripping leaves and twigs off tree-branches.
Only we, however, make machine tools that is, tools designed solely to assist in the manufacture of other tools. We have been doing so, moreover, at least since the Middle Paleolithic, as the exhumation of ancient "hammer" stones and "anvil" stones makes clear. And only we have demonstrated pyrotechnic skills, from cooking to smelting. (Whether such complex behavior patterns as farming, war, and slavery should be attributed primarily to our manipulative capacity is also moot. For ants, with tiny brains and no hands, also exhibit these patterns, which may be more social than technological in nature.)
In addition to its relative hairlessness, human skin has two other peculiarities that set it off from the bodily integument of the other primates. One is the layer of subcutaneous fat found throughout the body. This adult fat is supplemented by the "baby fat" which our offspring develop shortly before birth and retain till they begin toddling, making them substantially heavier even than infant gorillas. The other peculiarity of the human skin is sweating which, however, does not function as a cooling device in human infants until they are several weeks old.
Behaviorally, few traits set us off as strikingly from all the apes as our natatory abilities. We bathe, swim, and dive for the pleasure as well as for cleanliness, self-transportation, and food. The only other primates that voluntarily enter the water are proboscis, talapoin, and macaque monkeys. None of them, however, venture as far, move as fast, or go as deep in the water as we do.
The last of the trait-clusters that mark us as unique in our zoological order is physiological. Only human beings experience menopause. And only human beings exhibit longevity equaling or exceeding that of elephants and owls.
Of the various explanations offered to date for man's "anomalous apehood", the most widely accepted at present is the Savanna Hypothesis, whose ablest exponent is probably Sherwood Washburn, Professor Emeritus of Anthropology at the University of California. According to Washburn, the best way to account for human peculiarities is to assume that, between the Miocene Epoch, when our forebears were still arboreal, and the Pleistocene Epoch, when they began to make stone hunting-weapons, they adopted a terrestrial way of life in the African grasslands.(2)
Man's Pliocene descent to the ground, in this view, explains the following human anatomical traits:
It is also held to explain the human physiological process of sweating - as a means of cooling hunters during the chase. And it is further held to explain the human behavioral complex that centers on the use, manufacture, and elaboration of tools, without which our ancestors would have been dangerously vulnerable to predators on the open tropical plains.
By itself, the Savanna Hypothesis seems inadequate to explain the more conspicuous differences between ourselves and the other apes. As Mrs. Morgan observes (pp. 24-25), furriness does not in itself cause overheating, even in cursorial mammals. If it did, both gazelles and cheetahs should be furless. Bipedalism does not increase either the speed or the energy-economy of running but, on the contrary, decreases both (pp. 49-50). Moreover, quadrupedal locomotion does not necessarily prevent primates from carrying food or tools. Knuckle walkers like the chimpanzee regularly use their forelimbs for both functions at once (p. 51). Perspiration, finally, is not necessary for a large primate, even if it is hairy and runs fast. Chimpanzees remain dry-skinned whether pursuing small game or fleeing from predators (p. 40).
In place of the Washburn scenario, Morgan offers an Aquatic Hypothesis, in accordance with which our arboreal Miocene ancestors did not move directly from the trees to the ground, as did the gorillas and the baboons. Instead, they took a long Pliocene detour through the water before returning to a terrestrial existence in the Pleistocene Epoch. This hypothesis accommodates a number of human peculiarities that the Savanna Hypothesis does not. Salient among these are:
1. our erect stance, which is matched on land by that of the penguin and in the water by that of resting seals, sea-otters, dugongs, and manatees (p. 55);
2. our subcutaneous fat (pp. 38-42) and underwater swimming ability (pp. 70-72), in both of which respects we resemble aquatic birds and mammals but not other primates;
3. our glabrous skin (p. 41), which resembles that of currently aquatic mammals, such as the dolphin, and formerly aquatic mammals, such as the elephant;
4. our protrusive nose (p. 77), poor sense of smell (p. 97), weeping in response to physical or emotional distress (pp. 43-48), and voluntary control of nostril aperture, breathing, and vocalization (pp. 76 & 98); and
5. our protrusive bust and buttocks (p. 33 (3) ), our elongated penis and vagina,(4) our hymen(5) and doubled labia (p. 155), and our ventral coitus.
Among primates, our long nose is matched solely by that of the Proboscis Monkey the only non-human primate that crosses rivers and swims in the ocean over a mile from shore. Our sense of smell is the feeblest in the entire primate order and is exceeded in weakness only by that of birds and dolphins. We are the only weeping primate. But elephants also weep as do most aquatic mammals, birds, and reptiles. Voluntary control of breathing and vocalization is characteristic of seals and dolphins but not of terrestrial mammals. Besides ourselves, the only mammal that has a bust - that is, protrusive breasts - is the manatee, which is, like all sirenians, wholly aquatic. Ventral coitus, which occurs among no terrestrial mammals, occurs among all aquatic mammals. (Seals copulate dorsally on shore but ventrally in the water.)
As further evidence that our ancestors were once aquatic, Morgan also cites the webbing between our thumbs and forefingers (p. 77), the bradycardia that automatically slows our heartbeat when we dive (p. 73), and our fondness for bathing and adeptness at swimming, the latter of which has been found to extend to newborn infants (p. 79).
Predictably, Morgan's views have received almost no sympathetic attention from students of human evolution. When not ignored, her views have generally been derided, as by Jerold Lowenstein and Adrienne Zihlman, in "The Wading Ape: A Watered-Down Version of Human Evolution".(6) They stigmatize Morgan's hypothesis as a "nonscientific belief", compare her with Von Daniken, and, in keeping with this comparison, assert that "one could make an equally convincing case that our ancestors evolved in the air". In one of their few resorts to serious and substantive argumentation, they assert that no hominids "show . . . the skeletal adaptation to an aquatic environment . . . common to all other aqautic mammals: . . . reduction in the size of the hind limbs . . .".(7) This argument betrays either a surprising ignorance of the anatomy of the aquatic amphibians and reptiles or a disingenuous determination to ignore that evidence. As I myself pointed out in The Divine Animal, man's limb proportions are strikingly similar to those of frogs or marine iguanas, both of which have longer hind limbs than forelimbs.(8)
Happily, Morgan shows no inclination to try to explain everything in human evolution in terms of adaptation to water. She readily admits, for example, that our unique capacity to perspire and our development of axillary and pubic hair are maladaptive to a littoral existence. In fact, she assumes that, once the dry Pliocene gave way to the pluvial Pleistocene, our ancestors abandoned beach-combing for grass-land trekking. But she makes it clear that, had our aquaticism not necessitated the development of subcutaneous fat to protect us from chilling, our subsequent plains life would not have necessitated the development of sweat-glands to protect us against overheating.
In fact, she not only accepts the Savanna Hypothesis but embraces it as a necessary ingredient in a synoptic view of human evolution. To it, moreover, she adds Louis Bolk's Neoteny Hypothesis. Neoteny (also known as fetalism or pedomorphy) is the tendency in some species for adults to resemble the juvenile members of closely related species. Since infant apes have relatively hairless skins, big brains, and flat faces, we must be reckoned as neotenous with respect to apes. But, while regarding all three hypotheses as complementary (rather than mutually exclusive), she does not merely lump them eclectically. The Aquatic Hypothesis, she argues, explains our more striking deviations from the primate norm. The Savanna Hypothesis, however, explains our failure more fully to approach the norm for aquatic tetrapods. And the Neoteny Hypothesis explains the means by which our forebears were enabled to make two such radical ecological transitions - first from an arboreal to an aquatic existence, and then from an aquatic to a terrestrial existence (p. 105).
There are some clusters of human peculiarities which Morgan makes no effort to explain in toto. One such is constituted by menopause, unique to our species, and our longevity, which is equaled or exceeded by that of few other species. Here she follows Margaret Mead(9) in seeing the function of menopause as enabling older women to serve as teachers rather than as reproductives. But she leaves the associated longevity unexplained.
In a few cases, she overlooks data that would, I think, strengthen her Aquatic Hypothesis without in any way contravening the two supplementary hypotheses. One such datum is the webbing between the fingers of the Talapoin, a guenon monkey of the swamps of west-central Africa. Another is the eversion of the lips of our species, which are much fuller than those of other primates. The finger webbing of course, facilitates swimming; while the "lippiness" - like the labiality of our female pudenda provides firmer closure of a bodily orifice from which water and silt need to be excluded.
Morgan makes no claim to have originated the Aquatic Hypothesis. She gives full credit for it to Sir Alister Hardy, Professor Emeritus of Zoology at Oxford University. Between 1960 and 1977, Hardy published three articles on the subject, all of which are reprinted as Appendices to Morgan's book.(10) She is apparently unaware, however, that she has at least one other predecessor in aquatic theory. He is the late Carl Sauer, for some decades America's leading cultural geographer. In 1962, he published an article entitled "Seashore Primitive Home of Man?'',(11) in which he proposed that hominid bipedalism originated on the shores of the Indian Ocean.
The differences between Sauer, Hardy, and Morgan are marginal but significant and relate to the degree of immersion, both literal and theoretical, which each retrospectively envisions. Where Sauer saw early man primarily as beach-comber, Hardy sees him mainly as a wader and Morgan as an underwater swimmer.
I am myself in the line of Morgan's theoretical inheritance, at least to the extent that, in 1969, I published a book(12) giving positive consideration to all three of the evolutionary hypotheses which she treats in The Aquatic Ape. In it, however, I gave most of my attention to the Neoteny Hypothesis(13) and least attention to the Aquatic Hypothesis. I now think that her treatment of them, both as regards relative chronology and as regards the relationship of means and ends, is far better proportioned than was my own.
One well known writer on human evolution, who previously had grave reservations about the Aquatic Hypothesis, has apparently embraced it in recent years. According to Hardy,(14) Desmond Morris, author of The Naked Ape,(15) is now so well disposed toward aquaticism as to have considered co-authoring a book on the subject with him.(16)
An interesting appendix to The Aquatic Ape was written by Leon P. La Lumiere, Jr., of the Naval Research Laboratory in Washington, D.C.(17). La Lumiere, drawing on plate tectonic research done by Haroun Tazieff in 1970,(18) opines that, during the late Miocene and early Pliocene Epochs, the Afar triangle on the border between Ethiopia and French Somaliland was intermittently cut off from the northeast African mainland by vast lava flows and by intrusions of sea-water from the Gulf of Aden and the Red Sea. For about two million years, he thinks, dryopithecine hominoids were isolated here on "Danakil Island". As Pliocene desiccation shrank their forest habitat, they were forced, he argues, to forage in the water and to adjust to rock-fields strewn with basalt sherds and cooked organisms, both animal and vegetable. In time, these hominoids became agile swimmers and skilled fire-users. In the intervals between isolations, he suggests, these human ancestors, now bidepal and wielding stone tools, filtered in three waves out of the Afar triangle and down the Rift Valley of East Africa. The first wave, we know as Australopithecus; the second, as Homo habilis; and the third, as Homo erectus.
Since Morgan's scenario is implicitly catastrophic and La Lumiere's explicitly so, it may be worth noting an overlap in theorizing style between the aquaticists and the cataclysmic evolutionists, beginning with the late Immanuel Velikovsky. In each case, the "heretical" theory, though stigmatized as deviant and minoritarian by adherents of the prevalent consensus, shows itself to be conceptually broader and more inclusive than the consensus. Thus, cataclysmic evolutionists do not reject uniformitarian theory. On the contrary, they assume that 99% of geological time is characterized by biological uniformity. But they insist that all speciation and most extinction occur only during brief but crucial cataclysmic episodes.* In much the same way, aquaticists do not exclude either neoteny or savanna theory. But they insist on the primacy of the aquatic episode in explaining those human characteristics which diverge most sharply from the hominoid norm.
Anyone who is interested in studying and assessing the Aquatic Hypothesis (rather than merely swallowing it whole or dismissing it out of hand) ought also to read Morgan's earlier book The Descent of Woman.(19) For, even though this work is, as its title implies, oriented primarily toward prehistoric human females rather than males, it also contains some aquatica not found in The Aquatic Ape. Salient among these are descriptions of the unique features of human gluteal and genital anatomy and the way in which these features accommodate an aquatic or semi-aquatic existence.(20)
In addition, The Descent of Woman also makes a clearer correlation of the sexual dimorphism of our species with aquatic life. It indicates that women's smoother skin, more durable head-hair, and thicker subcutaneous fat are all examples of their more complete adaptation to water. (Older men could go safely bald because infants didn't need their hair to cling to in the water.)
On the other hand, I would not wish to give the impression that anyone who reads Morgan's earlier 258-page book need not read her later 170-page book. One aspect of The Aquatic Ape which makes it preferable - at least in my eyes to The Descent of Woman is that the earlier book, having been conceived in part as a paleontological critique of "male chauvinism", attacks the Savanna Hypothesis as "androcentric" and nicknames it "Tarzanism". In her later book Morgan seems to have got over her (understandable) exasperation with the male-dominated establishment and appears better able to fit the savanna experience into her own evolutionary reconstruction. Another advantage of the later book is that it is not handicapped by the author's effort, in the earlier volume, to do two things at once: defend women against one-sided scholarly put-downs and simultaneously advance the Hardy-Sauer view of our collective Pliocene baptism. In the later volume, she concentrates on proto-human aquaticism. Consequently, this book seems better integrated.
As regards quality of writing, The Aquatic Ape is to be commended for its clarity, fluency, and wit. It does contain misprints (e.g., "Laetolil", "coelocanth", and "vertibrate" for Laetoli, coelacanth, and vertebrate), but these are fewer than one might expect in an age like ours, when ever fewer people are willing to proof-read. The only bone that I would pick with her diction has to do with her use of the adjective "naked" to mean "hairless" (p. 23 and passim). While I realize that Desmond Morris set a precedent for this usage with his book The Naked Ape, I still think that it would be both clearer and more felicitous to restrict the word to its commoner meaning of "unclothed " .
There is one place in which Morgan's use of technical terms is flatly erroneous; and that is on p. 107, where she describes human infants, who are relatively helpless at birth, as "precocial", and in the offspring of multiparous species (such, presumably, as fish) as "altricial". In fact, these polar terms should be reversed, since precocial like precocious means "maturing early". whereas altricial - from Latin altrix, "wet-nurse" means "needing to be nurtured (until delayed maturity is attained)".
Such flaws, however, are refreshingly few. Overall, I heartily endorse The Aquatic Ape. What I particularly like about it is that Mrs. Morgan has taken what I regard as a sensible and productive approach to some of the more noteworthy anomalies of human anatomy, physiology, and behavior. In terms of my own neologisms, she has shown herself to be an able practitioner of "anomalistics" without falling into the trap of ''anomalitis''.(21) That is, she has made use of anthropological anomalies to help create a new and richly explanatory scientific paradigm, rather than merely exploiting those anomalies for the sake of mystification or amusement. Homo sapiens, she seems to be telling us, is not wilfully or inexplicably unique but meaningfully and predictably so. This is not to say that the Aquatic Hypothesis, even when combined, in proper sequence, with the Neoteny Hypothesis and the Savanna Hypothesis, explains everything about our species. It only partially explains our big brains and longevity; and it does almost nothing to explain humor, modesty, suicide, or religion. But it does go a long way toward making us seem a little less odd!
FOOTNOTED REFERENCES1. My initial inclination was to entitle this review-article (as the review turned out to be) "The Anomalous Ape". But that title was obviously too similar to the title of the book itself.
2. Sherwood L. Washburn, The Social Life of Early Man (Chicago, 1961).
3. Although Morgan deals with the protrusion of woman's breasts in this book, the cushiony quality of human buttocks is dealt with only in her earlier book The Descent of Woman (New York, 1972), pp.47-50.
4. The Descent of Woman, pp . 49-50.
5. Ibid., p .49.
6. Jerold M. Lowenstein & Adrienne L. Zihlman, "The Wading Ape: A Watered-Down Version of Human Evolution," Oceans Magazine (a review of The Descent of Woman), May 1980, pp. 3-6.
7. Ibid., p. 5.
8. Roger W. Wescott, The Divine Animal. An Exploration of Human Potentiality (New York, 1969), p. 7.
9. Margaret Mead, Presidential Address, annual meeting, American Anthropological Association, Minneapolis, Minnesota, 1960.
10. Alister C. Hardy, "Was Man More Aquatic in the Past?" The New Scientist, April 1960, pp. 642-645; "Has Man an Aquatic Past?" The Listener, May 12, 1960 (no pagination); and "Was There a Homo Aquaticus?" Zenith (the Magazine of the Oxford University Scientific Society), vol. 15, No.1, 1977, pp.4-6.
11. Carl O. Sauer, "Seashore - Primitive Home of Man?" Proceedings of the American Philosophical Society, vol.106, 1962, pp.41-7 (reprinted in Land and Life: A Selection from the Writings of Carl Ortwin Sauer, edited by John Leighly, University of California Press, Berkeley,1963, pp. 300-12).
12. Wescott, op. cit.
13. Especially in Chapter 4, "The Natural Superiority of Children," pp. 89-130.
14. (Appendix 2), p. 151.
15. Desmond Morris, The Naked Ape (New York, 1967).
16. Personal communication to the reviewer, March 15, 1979.
17. Leon P. La Lumiere, Jr., "Danakil Island: The Evolution of Human Bipedalism - where it happened, a new hypothesis".
18. Haroun Tazieff, "The Afar Triangle," in Continents Adrift, a Scientific American anthology, Introduction by J. Tuzo Wilson (San Francisco, 1972), pp. 13341.
19. Op. cit. (fn. 3).
20. Ibid., pp. 47-50.
21. Roger W. Wescott, "Introducing Anomalistics: A New Field of Interdisciplinary Study," KRONOS V:3 (Spring 1980), p. 48.