Scuttling the Aquatic Ape Hypothesis

29 08 2007

On our occasional trips to the New Jersey shore, my wife is always the first one in the water. While I’m cautiously wading in, dreading that final slap of cold water just below my waist, she’s already frolicking in the waves, egging me on to just jump in and get it over with. Eventually I too become submerged (either willfully or by force of a wave I never saw coming), salt water inevitably shooting up my nose. Don’t get me wrong, I do enjoy warm days at the beach, but on each visit it seems that I as an individual, if not a representative of a population or species, am not well-adapted to a near-shore marine existence. Followers of the Aquatic Ape Hypothesis* (AAH), however, beg to differ.

[* I say "hypothesis" and not "theory" (AAT) because the writings of Elaine Morgan and others do not have enough supporting evidence to garner it the more prestigious title of "theory." Given the current paucity of evidence and research, the Aquatic Ape Hypothesis is precisely that and no more.]

Before discussing the current manifestation of the AAH, we need to go back to a time when the truth of evolution had yet to fully take hold in the minds of scientists and philosophers. The Ionian philosopher Anaximander (610-546 BCE), student of Thales, suggested that the world first existed in an entirely aquatic state, the recession of the globe-consuming waters creating life. In From the Greeks to Darwin (1905), famed American Museum of Natural History president Henry Fairfield Osborn described the views of Anaximander as follows (a similar treatment is given in Osborn’s Man Rises to Parnassus, as well);

He conceived of the earth as first existing in a fluid state. From its gradual drying up all living creatures were produced, beginning with men. These aquatic men first appeared in the form of fishes in the water, and they emerged from this element only after they had progressed so far as to be able to further develop and sustain themselves upon land. This is rather analogous to the bursting of a chrysalis, then to progressive development from a simpler to a more advanced structure by a change of organs, yet a germ of the Evolution idea is found here.

We find that Anaximander advanced some reasons for this view. He pointed to man’s long helplessness after birth as one of the proofs that he cannot be in his original condition. His hypothetical ancestors of man were supposed to be first encased in horny capsules, floating and feeding in water; as soon as these ‘fish-men’ were in a condition to emerge, they came on land, the capsule burst, and they took their human form.

Like the works of many Ionian philosophers, the ideas and opinions of Anaximander do not seem to have taken hold (Aristotle ultimately becoming the preferred scientific and philosophical source for further consideration in Europe in centuries to come), and not much of his work remains. It is curious to note, though, that wrong as Anaximander was about the origins of humans, the reasons he uses to support his ideas (as relayed by Osborn) are very similar in approach to those of Elaine Morgan and some modern-day AAH adherents, as we shall soon see.

To the best of my current understanding, the hypothesis that man was a product of the sea did surface again until 1942 when Max Westenhofer of the University of Berlin published the book The Unique Road to Man. According to Donna Kossy’s book Strange Creations, Westenhofer’s treatment of an aquatic origin of mankind consisted of little more than mention of it as a promising hypothesis, however, and the outbreak of war prevented the professor from pursuing the line of inquiry further. The hypothesis would have to wait until March 5, 1960, when marine biologist Sir Alister Hardy presented a lecture on “Aquatic Man: Past, Present, and Future” to the British Sub-Aqua Club. The address caused quite a stir and led Hardy, who had been inspired by the layers of sub-cutaneous present in humans and some marine mammals he had seen skinned on a journey to the Antarctic in 1927, to write a series of articles in the magazine New Scientist to clarify his position on the subject. Kossy relates the words of Hardy from an April issue of the magazine (although the year is not specified);

My thesis is that a branch of this primitive ape-stock was forced by competition from life in the trees to feed on the seashores and to hunt for food, shell fish, sea-urchins, etc., in the shallow waters of the coast. I suppose that they were forced into the water just as we have seen happen in so many other groups of terrestrial animals. I am imagining this happening in the warmer parts of the world, in the tropical seas where Man could stand being in the water for relatively long periods, that is, several hours at a stretch. I imagine him wading, at first perhaps still crouching, almost on all fours, groping about in the water, digging for shellfish, but becoming gradually more adept at swimming. Then, in time, I see him becoming more and more of an aquatic animal going further out from the shore; I see him diving for shell fish, prising out worms, burrowing crabs and bivalves from the sands at the bottom of shallow seas, and breaking open sea-urchins, and then, with increasing skill, capturing fish with his hands.

Thus the more familiar image of the amorphous “Aquatic Ape” was born, wading out into the surf and feeling in the shallow sands for food. The early stage of such a transformation is awfully raccoon-like, as raccoons have incredibly sensitive hands that they use to feel about in streams and shallow waters for mussels, crayfish, and other morsels without being driven to become fully aquatic themselves. Nevertheless, the idea that man had his origins in a shallow sea rather than on a hot and brutal savanna was certainly controversial. Ever since Raymond Dart described the skull of the Taung Child in 1925 (shifting attention away from Europe and Asia for the origins of man) and the fossil assemblages of the South African caves were discovered, humans were thought to have evolved through a hunting culture, nearly every specialization that separates us from living primate relatives being due to our meat-craving societies. Indeed, the remains of Australopithecus found in South African caves (especially the jaw of a 12-year old child whose jaw appeared to have been fractured by a direct and accurate blow) like those Makapansgat suggested to Dart that these “proto-men” were not only skilled hunters, but also murderers and cannibals. Even though our understanding of these assemblages has greatly changed since Dart’s time (see C.K. Brain’s The Hunters or the Hunted?), the overall image of human evolution being intricately linked to meat-eating and hunting has dominated the discussion of our origins. Even more specifically, the considerations of our ancestors have nearly always focused on the male of the species, and even Hardy’s early ideas of an aquatic ape focused primarily on males.

In 1964, zoologist Desmond Morris published the bestseller The Naked Ape. Today the book is nearly useless outside of understanding the history of thought about human evolution, but when it was first published a short discussion of the AAH caught the attention of a woman named Elaine Morgan. On page 37 of the 1967 paperback edition, Morris states;

Another, more ingenious theory is that, before he became a hunting ape, the original ground ape that had left the forests went through a long phase as an aquatic ape. He is envisaged as moving to the tropical sea-shores in search of food. There he will have found shellfish and other sea-shore creatures in comparative abundance, a food supply much richer and more attractive than that on the open plains. At first he will have groped around in the rock pools and the shallow water, but gradually he will have started to swim out to greater depths and dive for food. During this process, it is argued, he will have lost his hair like other mammals that have returned to the sea. Only his head, protruding from the surface of the water, would retain the hairy coat to protect him from the direct glare of the sun. Then, later on, when his tools (originally developed for cracking open shells) became sufficiently advanced, he will have spread away from the cradle of the sea-shore and out into the open land spaces as an emerging hunter.

Unfortunately, [searching for fossils in marine or fluvial deposits or further research into the AAH] has yet to be done and, despite its most appealing indirect evidence, the aquatic theory lacks solid support. It neatly accounts for a number of special features, but it demands in exchange the acceptance of a hypothetical major evolutionary phase for which there is no direct evidence. (Even if eventually it does turn out to be true, it will not clash seriously with the general picture of the hunting ape’s evolution out of a ground ape. It will simply mean that the ground ape went through a rather salutary christening ceremony.)

[Emphasis mine]

Elaine Morgan read the brief treatment and qualifications (some of which has been omitted here for the sake of brevity) and wanted to know more about the possibility of our ancestors going through an aquatic stage of evolution. No information seemed to be available, and so Morgan wrote to Hardy in 1970, and he encouraged Morgan to push ahead with her research and desire to write a book about the AAH. The result was the bestselling The Descent of Woman, published in 1972. My copy is a little bit newer than that, being the Bantam 1973 edition, and featuring what appears to be a nude mother and child on the cover. Closer inspection reveals that something isn’t quite right, however; the mother I previously assumed was a representative of Homo sapiens looks like she’s been hit in the face with a frying pan. I didn’t know it at the time, but the text would reveal that the plump, nude, and long haired female on the cover was not drawn from life, but rather was Morgan’s idea of the Australopithecus specimen “Lucy” as Aphrodite.

Morgan’s first book is certainly a unique one, weaving in between “Just-so story” type paleo-fiction and long arguments about the female orgasm, including it’s fallacious mythical status. Indeed, the AAH only seems to occupy the first 1/3 of the book, only cropping up here and there in the following chapters, and receiving only a brief mention in the conclusion. Still, the way Morgan structures her argument in her first book will tell us much about her later works and the rise of the AAH as a popular idea. Early on in the work, we are introduced to a hypothetical female ape, not unlike Proconsul, living in Africa sometime during the Pliocene (~5.3-1.8 million years ago). During this time a hard life trying to find food and avoid predators was becoming even harder, Morgan hypothesizing that a terrible heat wave would change the way of life for many populations of these unnamed apes (from what I understand, however, the climate of the Pliocene began to approach our own and became cooler, drier, and had more seasonal distinctions rather than being a global hot-house).

Morgan’s ape was in a bit of a jam, that’s for sure. The water holes are said to be stalked by hungry cats and food was becoming scarce, and the imaginary female was not as fearsome or powerful as the males in her group. Eventually she was chased into the water by a large cat, and decides that, despite her distaste for water, “the seaside not at all a bad place to be. She found to her delight that almost everything on the beach and in the water was either smaller or more timid than she was herself.” Indeed, Morgan’s ape appeared to have found paradise. While other animals cooked during the “dog days of the Pliocene”, her ape (and by extension the population of apes) found what seems to be a sheltered and peaceful lagoon devoid of predators, scavengers, or other threats from either land or sea. “Leopards don’t come so far into the sea, nor sharks so near to the land,” we are told, and while leopards may not be attracted to water, sharks are well-known for their shallow water hunting habits. Crocodiles are not even considered, nor are stingrays, poisonous urchins, jellyfish, disease, infection, or any of the other biological problems that may come with an aquatic existence or change in ecological setting. The new home of the apes sounds better than Club Med, a watery Eden lacking in devious serpents and forbidden fruit.

As suggested by Morris and Hardy, the population of apes gets by on a diet of shellfish and relatively stupid sirenians that happen to come by, males making short work of the water-going creatures with rocks found along the shore. Given the amount of time that the apes would be spending in the water (they couldn’t have just subsisted by wading in or eating what washed up, or at least this is what is implied), bodies started to change. Males are paid little attention by Morgan, and the warm relationship between mother and child takes center stage. While most of the hair on the body would be lost as an adaptation to water (an odd conclusion given that otters, seals, and sea lions all are covered in hair), the hair on the head would be allowed to grow long, the water babies being able to curl their fingers into it and stay close to mom for a nap when they got tired of exploring off on their own. Conversely, breast feeding would still have to take place on shore, but the upright posture of the females (acquired from so much time in the water) would require the baby to be held at an awkward position in which they could not reach their mother’s nipples. This was solved by developing larger “hemispherical” breasts to reach down to the infant, even though larger breasts may cause infants problems when they try to get their mouths on them to breast feed (if the breast is so large that the infant’s nose is covered by it, breathing and feeding becomes difficult).

In searching for an aquatic example of such a striking characteristic, Morgan turns to the Florida manatee and other sirenians, many who have seen females with young noting the presence of “breasts” on the aquatic mammals. Interestingly enough, however, the manatee shares it’s ancestry with living elephants, the females of which also exhibit some rather sizable swellings when lactating. Robert Sapolsky, in his book A Primate’s Memoir, describes seeing such an unexpected shape on the chest of a female elephant for the first time;

Did you know that female elephants have breasts? I do not mean rows of teats, a mama elephant lying on her side with dozens of little piglet elephants nursing with their eyes still closed. I mean breasts, two huge voluptuous billowy mounds, complete with cleavage. I bet you had no idea, did you? Nor did I – it is a subject rarely broached in our public schools. I’m out in the bush that first month, armed with binoculars and stopwatch and notepad, spending the days carefully watching baboons mating left and right. And then, suddenly, some pachyderms come cruising past, and I see some elephant with these, well, breasts. And the natural first reaction is to think, Oh, great, I’m such a horny lascivious pathetic adolescent that after a mere month of isolation in the bush I’ve already cracked, I’m hallucinating breasts the size of Volkswagens on the elephants. Horrors, to have one’s psychotic break occur so soon, and to have it take the form of a puerile sexual obsession many embarrassing steps below gawking at National Geographic nudies. I was greatly relieved to eventually discover that the elephant’s breasts were real, that I was not having some Marlin Perkins wet dream.

It should be noted, however, that Morgan attributes an aquatic origin to elephants as well, primarily based upon their ability to shed tears (and therefore salt), as well as the ability of living Indian elephants to swim long distances in the ocean. Such considerations are a side trip from the main thrust of her argument, and no detail is given as to when, where, why, or how elephants arose from a water-dwelling species, only that a few characteristics in living animals point to an Aquatic Pachyderm Hypothesis.

Going back to the AHH, given about 10 million years in the water Morgan’s ape is substantially different than the one that was first driven into the waves by a predator. Referring to her as “Mrs. Australopithecus,” Morgan paints the following portrait (the artistic manifestation of which is found on the cover of the book);

So our hominid has a nose. I have no doubt that she also had fleshy nostrils, but considerable doubt that they evolved to make sex sexier for her mate. I think she was by no means the simian, cadaverous, lipless creature that artists sometimes reconstruct by covering her dug-up skull with a tightly fitting layer of hairy skin. The layer of fat which was rounding out her arms and legs and adding bulk to her breasts was also filling out her cheeks, and her nostrils, and her earlobes, and everting her lips… We would not have accounted her beautiful, with her low forehead and prognathous jaw, but the chances are that she was a chubby little creature with several superficial features resembling our own more nearly than they resembled any ape’s. And as for the expressions that flitted across that prehistoric countenance, her millions of years in the water had certainly left their mark on those also.

This is quite a different picture of “Lucy” than is often seen, but is there anything to it? Part of the advantage of the AAH is that Morgan doesn’t specify her ideas down to a scientific level, allowing her to poetically play with her ideas in any way she wishes, the female becoming more beautiful while the men continue to try and kill dugongs with rocks. This type of feminist reaction to the “Man the Hunter” narrative is the main connective feature throughout the book, and Morgan’s writing is far more concerned with the more graceful and beautiful evolution of woman, with sex ultimately bringing “sin” into the Garden.

In Morgan’s story, the genitals of the ancestral females went from facing backwards (making rear-mounting positions by the male easy) to facing downwards, a position that Morgan insists will not work for males, face-to-face mating being adopted as a must. Morgan’s reasoning for the change is that aquatic animals often undergo this type of genital shift (cetaceans are her primary example), but she generally ignores why the genitals should be shifted in the first place. In terms of cetaceans, the ancestors likely had their anal-genital openings in the position typical for quadrapeds; facing backwards at the location of the pelvis just under the tail, usually being at the most distal end of the body. As they evolved, the archaeocetes lost their hind limbs and their spines elongated, being the main source of propulsion, so rather than keep moving backwards with the spine the genitals stayed in the pelvic region “settled” on the ventral side of the body; where else they would have gone, I do not know. Given this morphological necessity, face-to-face mating became the only way cetaceans could copulate. Seals and sea lions, on the other hand, still have their anal-genital openings near the distal most parts of their bodies because that is where the pelvis is and there was no need to change mating styles, and males still mount females from behind. Even beyond such considerations, I do not see how the rear-mount strategy can be dogmatically ruled out, and I have a feeling that because such a position is considered “kinky” by some it was essentially ruled not to have happened. In fact, the retention of rear-mounting with the shift in female genitals could help explain elongation of the penis in males (they’d have to extend a bit farther), although this matter is far from settled. Curiously, Morgan generally ignores the bonobo and it’s face-to-face mating habits, even in her later books. She’s clearly aware of these apes (she does mention them and one graces the cover of The Descent of the Child), but they are conspicuously absent from discussions about sex.

Still, if we are to follow Morgan’s model, the apes would have to switch from mating using a rear-mount position to face-to-face (the males, we are told, couldn’t penetrate any other way), such a position causing much trauma for females. Males wouldn’t know how to calm the female for a face-to-face encounter, and it essentially led to either rape or an unfruitful attempt to mate. Morgan describes such a scene;

The primate was a totally different shape. Her new aquatic streamlining had been unable to prevent her becoming lumpy in the middle, and as a littoral biped her legs were developing in the opposite direction from the seal’s – they were becoming not smaller and thinner but farther apart, but longer and thicker and closer together. The seal’s solution was impossible for the aquatic apes. Their dilemma was unique.

So we left her on her back, kicking and struggling and frightened out of her tiny anthropoid mind, with her mate beginning to get irritated. When she saw him snarl and bare his canines she was finally convinced that he wanted her for dinner, and that her last hour had come. Further resistance was useless. She stopped fighting and signaled her submission, defeat, and appeasement as strongly as she could with so little room for maneuver.

Immediately, the incident was over. The male was a properly programmed animal, and it was impossible for him to go on clobbering a member of his own species that was giving clear indications that it had stopped fighting back. He moved a little way off, wearing a puzzled expression. He had thought for a moment that he was on to a good idea, but obviously there was a snag to it.

Such events removed us from our Eden along the shores, males taking up hunting on the plains soon after the eviction. Rains that quenched the African drought allowed the apes to leave the habitat that they had become so accustomed to (it seems like the males led the charge, being sick of their prolonged day at the beach), moving on to evolve in ways that fit the scientific orthodoxy of the times a bit more closely. Even so, Morgan suggests that women have retained the peace, beauty, and grace of their aquatic origins while males are more shaped by violence and hunting, her parting words being;

He is the most miraculous of all the creatures that God ever made or the earth ever spawned. All we need to do is hold out our loving arms to him and say: “Come on in, the water’s lovely.”

Oddly enough, such arguments seem more specific and in-depth than those in Morgan’s later works The Descent of the Child (1995) and The Scars of Evolution (1990). The Descent of the Child can largely be ignored, being that it’s primary focus is on doing for human babies (from conception through early childhood) what The Descent of Woman did for women, all-in-all being a string of facts presented to the reader in an easy-to-digest manner but without much further discussion. In covering past evolution, the “savanna hypothesis” and “man the hunter” are both alluded to or pointed out to be wrong, although no rigorous refutation is made. Instead the reader is referred to the earlier The Scars of Evolution for the “scientific” argument, but Morgan’s earlier poetry contains far more detail than the 1990 work. I breezed through the 178 pages of the book easily enough, but there was little positive evidence within it’s pages for the AAH. Certain physiological systems were pinpointed and deemed to be of aquatic origin since Morgan deemed no other hypotheses to be adequate (which, of course, assumes that all possibilities have been discovered and have received proper consideration).

I actually would love to write up a longer discussion of The Scars of Evolution but there is surprisingly little actual AAH evidence to be considered, and Morgan even makes some fairly basic mistakes about fossil preservation. Early on in the book she writes;

So if the prospecting had started in the north [of the Rift Valley] and worked down, popular illustrations of groups of Australopithecus would have shown them reclining under a shady tree at the water’s edge, living perhaps on fruit and greenery and fish. Instead, they are depicted as shaggy creatures trekking through parched grass and a scatter of stunted thorn bushes, turning to scavenging and hunting to supplement their diet.

This conclusion comes from Morgan’s assertion that some specimens of Australopithecus are found associated with fossils like crocodile remains and turtle eggs, suggesting an aquatic habitat. This largely ignores taphonomy, however, and an animal that dies in or near water being much more likely to be preserved and fossilized than one that drops out on the plains, the body undoubtedly being ripped apart by scavengers and leaving little or nothing to the fossil record. Most of the rest of the book covers material already mentioned in The Descent of Woman, like the fallacious notion that pheromones are essentially nonexistent or non-influential in humans because we went through an aquatic phase of evolution where scent wouldn’t have counted for much. Also curious is one of Morgan’s final statements about how evolution works, especially in regards to water. Rather than gaining specializations mentioned in so many of her works (i.e. the ability to cry and remove saline from the body, nostrils with possible flaps to keep water out, enlargement of the female breasts), a kind of de-volution of our ancestors is favored;

Conceivably, a species finding itself in a radically new environment (such as water) begins to shed the more advanced features which fitted it for its old environment. It back-tracks to a more unspecialized foetus-like form, before re-adapting to the new habitat. If that were the case, then our own ancestors, having moved from the land to the water and subsequently from water to land, would have been subjected to an impetus towards neoteny on two successive occasions. It would explain why in our case the trend was unusually powerful.

In all, Morgan’s work seem to be lacking of any rigorous research or hypotheses, and it led me to wonder why the AAH will simply not go away. Perhaps some of it is the mental appeal and the common error of linking correlation in evolutionary convergence to causation, working backwards to whatever ideal we hold most dear. Even if I’m incorrect as far as social motivation goes, the AAH has shown up in the scientific literature in the past few years, and it’s primary advocate seems to be Marc Verhaegen. Although the majority of his papers seem to be currently unavailable online, there is no name that more frequently appears in terms of AAH literature in scientific journals, giving the hypothesis some visibility (and credibility, as far as AAH advocates may be concerned). Some of the papers published on the AAH I could find are;

Bender R, Verhaegen M, & Oser N. “Acquisition of human bipedal gait from the viewpoint of the aquatic ape theoryAnthropol Anz. 1997 Mar;55(1):1-14.

Cunnane, S.C. “The Aquatic Ape Theory reconsideredMedical Hypotheses Volume 6, Issue 1, January 1980, Pages 49-58

Ellis, D.V. “Wetlands or aquatic ape? Availability of food resources.Nutr Health. 1993;9(3):205-17.

Rhŷs Evans, PH. “The paranasal sinuses and other enigmas: an aquatic evolutionary theoryJ Laryngol Otol. 1992 Mar;106(3):214-25.

Vaneechoutte, M. ” Report of the Symposium ‘Water and Human Evolution’, Gent, Belgium, April 30th 1999Human Evolution. 2000 Volume 15, Numbers 3-4

Verhaegen, M.J.B., Puech, P.F., & Munro, S. “Aquarboreal ancestors?Trends in ecology & evolution (Amsterdam). 2002 Vol. 17, Issue 5, page 212

Verhaegen, M.J.B. and Puech, P.F. “Hominid lifestyle and diet reconsidered: paleo-environmental and comparative dataHuman Evolution. 2000 Volume 15, Numbers 3-4

Verhaegen, M.J.B. “The Aquatic Ape Theory and some common diseases”. Medical Hypotheses
Volume 24, Issue 3, November 1987, Pages 293-299

Verhaegen, M.J.B. “The Aquatic Ape Theory: Evidence and a possible scenario
Medical Hypotheses Volume 16, Issue 1, January 1985, Pages 17-32

Verhaegen, M.J.B. “Aquatic ape theory and fossil hominidsMedical Hypotheses Volume 35, Issue 2, June 1991, Pages 108-114

Verhaegen, M.J.B. “Aquatic ape theory, speech origins, and brain differences with apes and monkeysMedical Hypotheses Volume 44, Issue 5, May 1995, Pages 409-413

[And for an opposing view see Langdon, J.H. "Umbrella hypotheses and parsimony in human evolution: a critique of the Aquatic Ape Hypothesis" Human Evolution. 1997, Volume 33, Number 4, pp. 479-494(16)]

As is immediately apparent, the great majority of the papers have appeared in one journal (Medical Hypotheses) and can be attributed to one author, Verhaegen. Judging from what I was able to find, many of the arguments that Verhaegen employs are very similar to those of Morgan, working backwards from somewhat contested or enigmatic human features to an aquatic origin to the exclusion of other hypotheses. Where Verhaegen differs, however, is that his aquatic hypothesis is far more broad than that of Hardy or Morgan. While Morgan implied that the aquatic apes were an isolated group that ended up leading to man (what happened to populations elsewhere is never spelled out), Verhaegen suggests that the last common ancestor of living gorillas, chimpanzees, bonobos, and humans was at least semi-bipedal and semi-aquatic, likely living in a habitat like a mangrove swamp. From the paper “Aquaborel ancestors?”;

A vertical posture and an ability to climb with the arms raised above the head could have helped a wading primate to enter or leave the water by grasping overhanging branches or waterside vegetation, and to grasp fruits above the water. Body enlargement and tail reduction would hinder agile arborealism, whereas a larger body is more easily supported in water and helps reduce heat loss (explaining why aquatic mammals are larger than related terrestrial forms). Tails would be of little use for a wading and/or swimming primate and would cause both drag and heat loss.

Thus Verhaegen attempts to separate New and Old World monkeys from apes by making the ancestors of all living apes at least partially water-bound, standing up to wade through water. Ultimately humans would have stayed in the pool while gorillas and chimpanzees got out, although gorillas, chimpanzees, and bonobos do not seem to show the same signs of being adapted to water that are often associated with humans under the AAH. Of further note is the fact that living primates like baboons, macaques, and proboscis monkeys have been known to swim and stand upright in water, although none seem to show signs of becoming exclusively adapted to an aquatic lifestyle. In the recent BBC series Planet Earth, baboons of the Okovango Delta in Botswana were shown wading through the water;

The baboons are not especially comfortable in the water, just as many other animals in the delta like cheetahs and lions don’t especially like crossing the waterways. Indeed, crocodiles are the primary danger in the water, and many animals seem to know of the threat all too well (but must cross from time to time, anyway). Such modes of moving through water, also seen in chimpanzees (see the final episode of the BBC’s Life of Mammals, entitled “Food for Thought”), seem to constitute the “weak” version of the AAH, and isn’t entirely unreasonable in explain possible motivation to become bipedal. It does require a certain ecology, however, (i.e. flooded plains, a swamp, shallow mangrove forest, lagoon, etc.) and has little explaining power out of such a context. Still, there are even more aquatic primates that were also featured in Planet Earth; the crab-eating macaques.

If we’re looking for a model of what an aquatic ape would look and act like, surely these monkeys would be it, and Morgan does note some of the aquatic habits of macaques (especially the behavior of washing food in water, as seen in Japanese Macaques). The problem is that macaques are monkeys, not apes, although they seem to get along in the water just fine. Unfortunately the adaptation of these primates to water is going to be slow and take many generations, but the study of these animals could give us some clues as to what the AAH can and cannot explain, although it seems that many of the features explained by the AAH don’t fit with what we see in the macaques. Looking at the underwater behavior, it would seem that the monkeys would be adapted to swim in a matter similar to that of quadrupeds rather than to start wading in, becoming bipedal, and then doing a breast-stroke. Indeed, the video shows that becoming bipedal is not a necessary precursor to being able to swim or becoming semi-aquatic, and it is quite possible (even probable) that primates could abandon the upright stage altogether. Standing upright seems to be generally uncomfortable for many primates, and it’s hard to see how primates introduced to a fruitful aquatic habitat would want to stand up before just jumping in if there was really nothing to fear in the waters. Even in the weak version of the AAH, it is hard to see how standing upright while crossing a river would have selected for bipedalism as it seems that many primates are capable of doing it over short periods and it does not hold any strong advantage that would relate to mating success or overall survival. Unless the hypothetical apes lived in an area constantly flooded, requiring them to stand up much of the time, it is difficult for me to imagine how water could have helped to select for an upright posture.

The overall problem I have with Morgan’s hypothesis about apes becoming almost exclusively aquatic is that it forces us to make a choice of one habitat or another. Mentions are made of Proboscis Monkeys and Macaques enjoying a swim, washing off food, or living near water, but they don’t seem to be bent on the same path as the one Morgan proposes. Organisms certainly are plastic, and they don’t rigidly abide by the “rules” set down by those that describe them as to where to live, what to eat, and how to act properly. In fact, it seems more reasonable to me that primates past and present would take advantage of an aquatic resource if readily available, but still maintain their terrestrial life unless they were so isolated that they had no choice for food other than the water. Time will tell if some of today’s semi-aquatic primates ever become more fully at home in the water, but I see no reason to believe that our ancestors decided to take a prolonged summer vacation on the beach, proceeding in a way that just so happened to explain everything neatly (if un-parsimoniously).

The AAH hinges on apes willingly going into the water for safety from predators, but this is only a Just-So story without the details. It also ignores the fact that the water can be almost as dangerous, if not moreso, than the land, and there are predators in the water just as there are in terrestrial habitats, not to mention rip-tides and other problems inherent to the ocean itself. While Morgan, in The Descent of Woman, states that newborns could be left to paddle about on their own while mom went about her own business, such maternal inattention doesn’t seem like it would be especially effective in making sure that young made it to adulthood. Only the calmest, most sheltered, and safe of lagoons would have allowed for this. If the AAH is to be taken seriously in whatever form, it is going to require rigorous ecological study, and so far it seems that it relies far more on post hoc arguments than actual evidence.

While Jim Moore has already done a fantastic job dismantling the various problems with the AAH, I hope I have helped to illuminate the overall lack of evidence for the idea. As an idea it’s not a bad one, but it seems to have never gone beyond hypothetical situations and Just-So stories, and most of the ideas associated with the AAH seem to be criticisms of other hypotheses, therefore leaving the AAH as the only alternative. While I can certainly appreciate the frustration Morgan and others must have felt (and even still feel) towards a male-dominated field in science and consideration being mainly given to the strong, archetypal male, I feel that the AAH is taking things too far in the other extreme. It is hard to ignore the feminist underpinnings of Morgan’s writing and the overall disregard for the big picture in order to bring women and children into closer focus. Combating a hypothesis you don’t like with an equally narrow one, just reversed, is not the way to bring greater understanding of our evolutionary history, and given that hominids and apes are so close to us, it’s easy to fall into trapping of preference. Being that I am no expert on the matter, however, I will close with T.H. Huxley’s final words from his work Man’s Place in Nature, as they seem to resonate with the big questions about our origins that remain unknown;

Where, then, must we look for primeval man? Was the oldest Homo sapiens pliocene or miocene, or yet more ancient? In still older strata do the fossilized bones of an Ape more anthropoid, or a Man more pithecoid, than any yet known await the researches of some unborn paleontologist?

Time will show. But, in the meanwhile, if any form of the doctrine of progressive development is correct, we must extend by long epochs of the most liberal estimate that has yet been made of the antiquity of Man.

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36 responses

29 08 2007
Richard Carter, FCD

A-ha! You are evidently unaware of my Surprise new evidence in support of the ‘Aquatic Ape’ hypothesis.

Nice article, though.

29 08 2007
laelaps

Thanks for the link, Richard. I have to admit that the new evidence is startling… I may have to revise my entire premise ;)

29 08 2007
Zach Miller

Your quotes from Morgan make it sound like woman has evolved to her modern form while man has remained an ape-man. And it really does come off as an uninformed feminist rally against the traditional explaination of how modern man came to be, which bothers me (a lot).

Great post, though. I assume it’s your contribution to Das Boneyard. :-)

29 08 2007
Will Baird

By Jove!

That was a sound thrashing!

Well done!

29 08 2007
laelaps

Thanks for the compliments Zach and Will. I actually have something else up my sleeve for The Boneyard (shh… it’s a secret), but if I can’t get it finished in time this will do as my contribution.

And extra points go to you, Will, for using the phrase “By Jove!” I figured I had to write something about this after spending the last few nights reading all about this nonsense.

30 08 2007
Christopher Taylor

The “Aquatic Pachyderm” is not so unbelievable, at least in the long and open term. The probable sister-group of proboscideans, sirenians, are aquatic, and basal proboscideans such as Moeritherium aren’t unbelievable as semi-aquatic hippo-type animals. On the other hand, elephants crying and elephant breasts are not a factor in supporting this suggestion, so this might be a case of being right for the wrong reasons.

If a primate was to become aquatic, I can more easily imagine it as a browsing omnivore of crustaceans, worms, and maybe aquatic plants, as shown in the video. In this case, wouldn’t pachyosteosis as seen in other bottom-feeding aquatic tetrapods (sirenians, marine iguanas, Thalassocnus, maybe basal proboscideans as I’ve already mentioned…) be a much more likely adaptation than a cetacean-like lightening?

30 08 2007
laelaps

Hi Chris. I don’t have much of a problem with a semi-aquatic elephant ancestor at some point, and some of the proboscideans seem to have been adapted to scooping up big mouthfuls of soft water plants. I just doubt that they went through an entirely marine phase sometime in the last 10 million years, then coming back on land. It’s more of an aside based upon the elephants ability to shed tears (although they don’t have the same configuration for doing so as us).

I also think that pachyosteosis as seen in some of the early archaeocetes would make more sense, especially if coupled with greater lung capacity. Like the video shows, young crab-eating macaques seem to like to swim underwater, but they seem to have to fight a bit to keep underwater. Unfortunately it seems more like fun than anything else, and there doesn’t seem to be a strong selective pressure for them to become more aquatic (especially if much of their time is still spent in trees).

30 08 2007
Waterlogged Weblog « Laelaps

[...] Scuttling the Aquatic Ape Hypothesis [...]

30 08 2007
johannes

I might be kicking a dead pig here, for you have already given the AAH what Will has approbiatly called a sound thrashing (well done indeed), but I think beaches and the seacoast were anything but a save refuge in Pliocene Africa. You have already mentioned sharks and crocs. Some seals can be quite nasty, too, especially the old, gnarly males. Brian has blogged about this. And then there was Agriotherium – very similar to Arctodus (shudder). Bears usually love water.
If a grizzly can catch a salmon, and an ice bear can catch a seal, Agriotherium would have been perfectly able to catch a (speculative) aquatic hominid.

30 08 2007
laelaps

Thank you, once again, for your contribution johannes. I agree that the shores of a Pliocene beach was anything but a refuge, although I didn’t know about Agriotherium. I’ll have to look into that a bit more (and maybe write up something on Pliocene beach ecology). Thanks again for sharing!

30 08 2007
DDeden

Brian, have you read Elaine Morgans book The Aquatic Ape Hypothesis?

30 08 2007
laelaps

That’s actually the only one of her books that I haven’t read yet (I read the rest this past week in succession). I intend to soon, as I have heard it puts forth a slightly more scientific case than some of the other books, and if I need to make changes to some of my ideas I will when I get the chance to read it. Still, from what I can tell from her works and the professional papers put out since the 1980’s, I don’t think it’ll change my opinion very much.

30 08 2007
DDeden

Yeah, I don’t think I read that one either.

My view is that us humans as a species are the most aquatically adaptable ape/anthropoid/primate, and it’s interesting to see how that could have happened in the evolutionary sense.

31 08 2007
laelaps

DD; Thanks for commenting again. I don’t know if I would agree that humans are the most aquatically adaptable primate. We do ok in the water, but I don’t think that we’re particularly graceful or well-adapted in the water, at least not to the point where we’d be providing competition for any other water-dwelling species. Like the video of the crab-eating macaques also shows, some monkeys seem to do just as well in the water as we do without any of the specialized adaptations to the AAH. Like I mentioned in the post, I am a little more open to the weak version of the AAH (flooded areas helping to select for bipedalism), but I don’t think Morgan’s strong version has much to support it at all.

31 08 2007
gregladen

I don’t think it’s a hypothesis. It’s really more of a moving target, as over the years various aspects have disappeared as they became more clearly wrong. (Like the girls have long hair, boys have short hair, so the females are having their young hang on to the long hair while they suckle form … whatever whatever)

AAMT

31 08 2007
DDeden

Can you think of any non-human primate species that lies on it’s back in water like a marine otter or sea otter and can propel itself comfortably in that position?

1 09 2007
johannes

In his controversial paper on the ecology of Arctodus and Agriotherium (Cameron has blogged about it)*, Sorkin (2006) has argued that the Brown Hyena, Parahyena brunea, is the nearest living ecologic equivalent of Agriotherium. Parahyena is notorious for its beachcombing habits, it patrols beaches on a regular basis, looking for beached whales, carcasses of fishes and seabirds, and attacking seal pups.
This behaviour is so typical of the animal that it is called “Strandwolf” – beach wulf – in Afrikaans.

* This whole predator vs scavenger thing seems to be pointless to me; most
predators take carrion if they find it, and most scavengers hunt if they
have no other choice. If you are as big and scary as Agriotherium, you pro-
bably just eat what you want.

4 09 2007
Mario Petrinovich

Sharks never encountered terrestrial meat, so meat that doesn’t have odor on fish isn’t a food for them.
The predator problem in shallow waters is big. Cats leap well in shallow waters. OTOH, deep waters of rocky coast is another thing. Primates use cliffs as sanctuary, as well as trees. I think that everything in our derived leg morphology points to vertical cliff climbing. Cliffs are safe places for us. If predator chases you, you climb a cliff, take one sharp stone, and hit it directly into predator’s head (who is in water, below you). OTOH, shellfish is an easy “pick” for a primate (see: racoons). Cliffside living is pretty plausible for an ape. In such environment, Mediterranean environment, you have small tree fruits. On land we are slow, but running downhill (towards the sea coast) we are alright. I see this as an ideal place to live, both, regarding food, and regarding predators. We still eat salty food (food without salt is tasteless food for us). Salt chrystals damage fur (as can be seen in the case of marine otter). For me, everything fits nicely into its place in a rocky coast Mediterranean environment.

8 09 2007
Evolution » Aquatic Apes

[...] I’d like to recommend a look at this lengthy and very informative discussion of the Aquatic Ape Story. [...]

20 09 2007
What?! « Laelaps

[...] between mother and child has even less support for it than another feminist idea of evolution, the Aquatic Ape Hypothesis, and it seems like a continuation of the popular mythology that humans were once “in [...]

23 10 2007
falasha

Actually, more evidence for aquatic ape is being discovered each day.

The method of reproducing in all other species has been the great determinate of the theory of their environment. Why don’t we give homo same consideration? Pregnant women hauling around fat babies would be easy prey on savanna. Also, what about preclampsia?

30 10 2007
Latest Book Reviews

Latest Book Reviews

I couldn’t understand some parts of this article, but it sounds interesting

15 04 2008
Lazaros Filippidis

You might find the article on BBC quite interesting. It talks about the aquatic ancestor of elephants.

15 04 2008
Lazaros Filippidis

and here is the link just in case nobody clicks on my name….. http://news.bbc.co.uk/1/hi/sci/tech/7347284.stm

25 04 2008
Paul McAlenan

I just wanted to say that Wegner postulated ‘Continental Drift’ in the early 20th century. He gained a Ph.D in Astronomy but was mostly remembered as a meteorologist. His idea was ridiculed at the time by those that should know – the geologists!

It wasn’t until the 50s that the idea of moving continents was revisited and in the 60s, quite possibly with Vines ‘discovery’ of sea floor spreading, that the modern theory of plate tectonics was born.

10 09 2008
H.Bos

Personal impressions have little value unless they have been followed-up.
One could have a chat with a Thursday-sland fisherman to get an idea of the dangers along the sea shore! It is simple a case of one who gets to live there learns to get by!
We are so adaptable from birth, be it arctic or tropical, from birth we can adapt. Unfortunately babies do not write many assays like already adapted adults do, thus we just have to guess their impressions.
Strangely no one has yet bothered to ask why babies put-up with whatever environment they are born into!
Babies are born every day and more are to come, no need to look for ancient artifacts, the evidence is there!

Just an imaginary birth scenario from the pont of an aquatic ape baby:

I am escaping from my safe but confined world and in desperate need for air.
i must go up to take a breath and I do paddle like mad.
As i go up i am washed clean and upon surfacing sputter a bit but manage to take a breath of air. I feel hair and my fist clench onto it, then i muzzle about untill someting slips into my mouth, mm this feels good and iam getting sleepy now. Before I drop off a little secret, it is not he, it is not she, it is it who evolves!
Regards from another ignorant ill informed elderly person.
H.Bos.

28 09 2008
Uegedei der Säufer

i hate it, but i must say this, you respond to the theory in the way of the theory you say is false. i read a half of your writing and i think you make the theory only complex without ruling it completly out. beside i think is pitiful to go into the subtleties. the forensic gave us a way to tell what the victim has eaten and lived before it died, we could even reconstructe its diet. this goes through isotopy analysis: http://blogs.nature.com/news/thegreatbeyond/2008/04/elephants_aquatic_ancestor.html . there exist fossils of our ancestors, why not reconstruct from their bonematerial thier diet and living habitat.

the most important thing in this discussion is, to analyse the nown quantitavies datas and to see which habitat could be ruled out for their time of life. so that the debate will be normalized.

15 02 2009
Dick Stone

I am doing a lot of research into AAT/AAH or AAG(guess) and I am trying to get as much opinion from both sides as I can. So far the con comments align pretty well with this article.
Your contentions rely heavily on only a of couple points. First you use the history of the idea as a stone to throw, as if because Aristotle’s one time belief that heavier objects are accelerated faster was wrong, therefore further ideas of gravity must be wrong. With time and research things, ideas, theories change. Yes, I’m sure you know this but then why make it part of your argument.
Secondly, you seem to be more interested in making fun of Ms. Morgan’s ability (or lack thereof) to imagine a more convincing scenario. I agree, she is wanting in that. However much proof it is that she is a poor writer, its no proof pro or con of anything beyond that. By your own reasoning then; two-thirds of your essay is irrelevant, therefore the whole is false. No? Left shoe, meet right foot I suppose.
Thirdly and most sadly, you seem to be anti-feminist. This calls into question your anti-evidence. Which is wishy-washy at best anyway.
Now I don’t mind that you don’t like the ladies, its none of my business. But you should know DNA mapping has shown a maternal link to the Afar region of Africa. And recent core sampling is giving us a much wetter picture of Africa some three million years ago. I still haven’t made up my mind one way or the other, yet. Arguments like yours are helping me lean more in favor of AAT.

15 02 2009
Dick Stone

Dang! Messed up.
I meant: “core sampling is giving us a much wetter picture of Africa some three HUNDRED million years ago.” My bad.

31 03 2009
DDeden

“The Government of Kenya has for several years sponsored an athletic contest among the various tribes, the test being one of strength for which they use a tug-of-war. One particular tribe has carried off the trophy repeatedly. This tribe resides on the east coast of Lake Victoria and lives very largely on fish. The members are powerful athletes and wonderful swimmers. They are said not to have been conquered in warfare when they could take the warfare to the water. One of their methods is to swim under water to the enemy’s fleet and scuttle their boats. They fight with spears under water with marvelous skill. Their physiques are magnificent. In a group of 190 boys who had been gathered into a government school near the east coast of Lake Victoria only one boy was found with dental caries, and two of his teeth had been affected. The people dry the fish which are carried far inland.” Nutrition and Physical Degeneration, Author: Weston A. Price
link

28 09 2010
jack

What of the troop of proboscis monkeys that were filmed walking upright, in single file and with babies on their hips in the human fashion, when they crossed stretches of dry land between areas of wading-depth water? That does seem to be partway between swimming monkeys like Allen’s Swamp Monkey (which can obviously hold its breath for considerable periods of time, if you’ve ever watched them, but otherwise move like a typical monkey) and what the AAH is proposing for us.

4 11 2010
Marc Verhaegen

Hi all,
AAT today:
– Mio-Pliocene hominoids (incl.apes & australopiths) = aquarboreal (misspelled above!) = aqua+arbor: swamp/mangrove/flooded forests & later wetlands (large size, tail loss, central spine, lateral arms, broad thorax & sternum = vertical swimming + grasping branches above the swamp = partial surface-feeders, collecting aquatic herbs & waterside foods, papyrus, hard-shelled invertebrates etc.
– Pleistocene littoral Homo = diaspora of H.erectus & relatives along coasts (+ inland along rivers) to different continents & islands (incl.Flores) = partial slow divers for sessile foods = bottom-feeders: explains SC fat, fur loss, huge brain (DHA), head-spine-legs on 1 line, external nose, pachyostosis in erectus, stone tools etc.etc. Of course, erectus & relatives butchered stranded whales (Dungo V, Angola, Paleolith.) as well as herbivores trampled (trek) or drowned at the waterside, as well as palmnuts, turtles, eggs etc. They didn’t run over open plains of course (too slow, heavy & fat), but simply spread along coasts & rivers.
Please google “econiche Homo”.

4 11 2010
Marc Verhaegen

forgot to say:
It’s well possible that these littoral Homo lived on the exposed continental shelves during the glacials, and ventured inland along rivers during interglacials &/or summers. Neandertals are found at coasts & inland, I guess they collected seafood during winter & trekked inland along rivers during summers (eg, salmon trek?), where they hunted (ambush?) or scavenged herbivores in mud or shallow water, but also fed on cattails (traces on neandertal tools).
IOW, AAT (littoral Homo) is much mor recent than often thought.

31 08 2011
hayley

“During this time a hard life trying to find food and avoid predators was becoming even harder, Morgan hypothesizing that a terrible heat wave would change the way of life for many populations of these unnamed apes (from what I understand, however, the climate of the Pliocene began to approach our own and became cooler, drier, and had more seasonal distinctions rather than being a global hot-house).”

Not global! We are talking about Africa only(!) in the context of AAH. And you have failed to even read the whole page the Wikipedia offers on Pliocene .. sad sad sad … too long to read it till the end? I highly doubt you have any valid geological or similar knowledge, because you almost cite Wikipedia on this subject. We have global raise in temperatures and icecaps melting and what? in some places winters are harsher then they were in a very long while? paradox or contradiction? No! Climate is not the same everywhere and consequences of its change may be very different in different parts of the globe! We haven’t had the exact same climate all over the world you know… or you might not know. Never left the States much?
I don’t have the time to trace the rest of the half read/half misunderstood Wikipedia entries you might have put into you text.
And Morgan’s books are even longer than an average Wiki entry…

28 09 2011
Marc Verhaegen

FYI, our publications on AAT after 2008:

M Verhaegen & S Munro 2009
“Littoral diets in early hominoids and/or early Homo?”
in NI Xirotiris cs eds 2009
“Fish and Seafood – Anthropological and Nutritional Perspectives”
28th ICAF Confer Kamilari Crete abstracts :37-38

S Munro & M Verhaegen 2009
“Pachyosteosclerosis suggests archaic Homo exploited sessile littoral foods”
ib.:28-29

M Verhaegen 2010
“Oi, big nose!”
New Scient 2782:69 Lastword 16.10.10

M Verhaegen & S Munro 2011
“Pachyosteosclerosis suggests archaic Homo frequently collected sessile littoral foods”
HOMO – J compar hum Biol 62:237-247

S Munro & M Verhaegen 2011
“Pachyosteosclerosis in archaic Homo: heavy skulls for diving, heavy legs for wading?”
in M Vaneechoutte, A Kuliukas & M Verhaegen eds 2011
“Was Man More Aquatic in the Past? – Fifty Years after Alister Hardy – Waterside Hypotheses of Human Evolution”
ebook Bentham Sci Publ :82-105

M Verhaegen, S Munro, P-F Puech & M Vaneechoutte 2011
“Early Hominoids: orthograde aquarboreals in flooded forests?”
ib.:67-81

M Vaneechoutte, S Munro & M Verhaegen 2011
“Seafood, diving, song and speech”
ib.:181-9

15 04 2013
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We cannot overlook the fact that trees provide homes to birds that help eradicate nasty bugs,
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Here are some of the worst Christmas gift ideas for men, gifts you should perhaps pass up unless, of course, you want the man
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