Evolution: a new boost for ‘aquatic ape’ theory
by Robin Mckie / May 4, 2013
It is one of the most unusual evolutionary ideas ever proposed: humans are amphibious apes who lost their fur, started to walk upright and developed big brains because they took to living the good life by the water’s edge. This is the aquatic ape theory and although treated with derision by some academics over the past 50 years, it is still backed by a small, but committed group of scientists. From next Wednesday through Friday, they will hold a major London conference when several speakers, including British naturalist and broadcaster, David Attenborough, will voice support for the theory. “Humans are very different from other apes,” said Peter Rhys Evans, an organizer of Human Evolution: Past, Present and Future. “We lack fur, walk upright, have big brains and subcutaneous fat and have a descended larynx, a feature common among aquatic animals but not apes.”
Standard evolutionary models suggest these different features appeared at separate times and for different reasons. The aquatic ape theory argues they all occurred because our ancestors decided to live in or near water for hundreds of thousands or possibly millions of years. The theory was first proposed in 1960 by British biologist Sir Alister Hardy, who believed apes descended from the trees to live not on the savannah as is usually supposed, but in flooded creeks, river banks and sea shores — some of Earth’s richest sources of food. To keep their heads above water, they evolved an upright stance, freeing their hands to make tools to crack open shellfish. Then they lost their body hair and instead developed a thick layer of subcutaneous fat to keep warm in the water.
Scientists have since added other human attributes of claimed aquatic origin, including the sinus, said Rhys Evans, an expert on head-neck physiology at the Royal Marsden hospital, London. “Humans have particularly large sinuses, spaces in the skull between our cheeks, noses and foreheads,” he added. “But why do we have empty spaces in our heads? It makes no sense until we consider the evolutionary perspective. Then it becomes clear: our sinuses acted as buoyancy aids that helped keep our heads above water.” Other paleontologists dismiss parts of the theory. One or two human features could have arisen because our ancestors picked homes near the sea, but the entire package of attributes — lack of fur, upright posture, big brains, sinuses and others — is just too much, they add.
It is not just human physiology that reveals our aquatic past, say the theory’s supporters. Our brain biochemistry is also revealing. “Docosahexaenoic acid (DHA) is an omega-3 fatty acid found in large amounts in seafood,” said Dr. Michael Crawford, of Imperial College London. “It boosts brain growth in mammals. That is why a dolphin has a much bigger brain than a zebra, though they have roughly the same body sizes. The dolphin has a diet rich in DHA. The crucial point is that without a high DHA diet from seafood we could not have developed our big brains. We got smart from eating fish and living in water. “More to the point, we now face a world in which sources of DHA — our fish stocks — are threatened. That has crucial consequences for our species. Without plentiful DHA, we face a future of increased mental illness and intellectual deterioration. We need to face up to that urgently. That is the real lesson of the aquatic ape theory.”
Originally outlined by biologist Alister Hardy, the aquatic ape hypothesis achieved prominence when Welsh writer Elaine Morgan took up the theory in the early 1970s. (Her previous work had included writing episodes of “Dr. Finlay’s Casebook.”) Morgan became infuriated with male-dominated explanations for human attributes such as hairlessness. According to prevailing ideas, human males lost their body hair when they took up hunting and needed to sweat profusely in the African heat. But no explanation was given to account for loss of female body hair. As a result, Morgan turned to the aquatic ape theory, which she believed provided a more balanced vision of human evolution. Morgan wrote a popular account of the theory, “The “Descent of Women,” which became a best-seller on both sides of the Atlantic. This has been followed up by other books on the subject including “The Scars of Evolution” and “The Aquatic Ape Hypothesis.”
The so-called Aquatic Ape Theory (AAT) is very well known. Ask an audience of people interested in human evolution if they’ve heard of it and practically all of them will put their hands up. If you then ask them if they think it’s a good idea, almost all of them will put their hands down again. Now, if you ask them to tell you what it actually is… it is interesting to see how many put their hands back up again. I did this in December 2004 at the ASHB (Australasian Society for Human Biology) conference in Canberra, Australia. A few did indeed put their hands back up until I qualified the question a little by saying that I didn’t mean “what you think the hypothesis is” but “whether you could remember reading a paragraph in the literature where it was unambiguously defined”. After that, no-one had their hand up. So, basically the situation regarding the AAH appears to be something like this: It’s an idea about human evolution that everyone has heard of, that most people think is rather silly, but no-one can tell you, unequivocally and authoratatively, what it is! (Click on one of the links here for more details or here to see the presentation itself.) Now I do not think that is a very strong basis for a refutation. Indeed, if you spend time looking through the scientific literature for that key refutation, that winning argument as to why it is wrong or a single piece of evidence which even implies it might be wrong (forget the notion of disproof in matters to do with paleoanthropology) I predict you will have a frustrating time.
There are very few pieces in the scientific literature (in English only, I’m afraid, I wouldn’t dare comment on other languages) which discuss it properly, a clear minority of which attempt some kind of rejection. The most significant, volumnous and balanced is still Roede et al 1990. It includes 22 papers, pitching 11 in favour of the AAH against another 11 critical of it, rather as if it symbolised some ‘grand final’ football match. Overall, the conclusion of the authors was against the AAH but readers should understand that, if this was a football match, it was no thrashing. A closer analogy would be more like a 1-0 win after a hotly disputed penalty decision in injury time that crept over the line after hitting the goalie and both posts. Apart from the 11 papers in Roede et al against the AAH, I’ve only found 5 others that attempt some kind of critique, and none of them are very good. (Click here for details.) In comparison there are over 40 pieces of literature by proponents (excluding the 11 in Roede et al 1990) and at least another 4 papers that are neutral. In science there is no concept of ‘majority rule’ or democracy but even so, with less than 30% of the entire published literature on the AAH critical of it (and most of that just uses straw man arguments) it’s difficult to see how the ‘aquasceptic’ view appears to have won primacy. One is tempted to ask: How did that happen? And on what basis were the three rejections made?
It is the purpose of this web site to suggest that this hypothesis has simply been misunderstood and as a consequence exaggerated from the start. If one forgets the images of primate seals, or mermen and women which presumably must have flashed in the minds of most critics and, instead, simply take the original proponent, Sir Alister Hardy, by his word and ask the question ‘Was Man More Aquatic in the Past?’ (with the emphasis on the word more) it is my understanding that the idea is perfectly plausible. After all we do swim better than our nearest relatives the apes. We do have some traits which are unusual in primates but quite common is some aquatic species. Apes do tend to move in shallow water in the same way we do on dry land… bipedally, a characteristic almost no other mammal shares with them. I’ve spend much of the last ten years of my life studying this area back in academia and the more I do the more convinced I am that the idea might well be right, if only one’s impression of what it’s actually claiming is scaled back a little. Of course the evidence we have indicates that there never was an aquatic ape (in the sense that a seal is an aquatic mammal), but who really ever thought there was? I didn’t. I’ve always taken the AAH to mean that our ancestors lived next to water and, occasionally waded, swam and dived, that they were merely more aquatic than our ape cousins. People have tended to assume that only very strong selection pressure could have caused the differences between apes and humans that we see but no-one seems to have questioned whether the same profound changes might have resulted from even very slight levels of selection.
The risk of drowning (and hence the likely selection of traits to reduce that risk) is disproportionately high compared to the percentage time one needs to spend in water for it to happen. This, I think, is the key point about this idea that everyone, both sceptics and proponents, have misunderstood most. I have become convinced that the so-called “aquatic ape hypothesis” has been unfortunately mislabelled and as a result understandably misunderstood, and then quite outrageously misrepresented. My aim in building and maintaining this web site is to try to help correct this trio. Firstly, “it” should be renamed. And, already there we come to a problem. It is not an “it”, it should be a “them”, as in the plural. One key misunderstanding of the this idea is that there is just one hypothesis when, actually, there are several. They vary in the proposed timescale for a “more aquatic” phase or phases, the specific habitat or scenario being proposed for this, the degree of selection required and the specific evidence used to support it. This makes it quite a challenge to define but, at least they are all based on selection from moving through water so, I think, it is possible to find a kind of “lowest common denominator” of them and take it from there. So, I suggest we rename them “waterside hypotheses of human evolution” (as first suggested, I think, by Philip Tobias) and then defining this umbrella label as clearly as possible. Hopefully, as a result, it will no longer be misrepresented and instead, at last, some decent science will actually be done to test it.
So, let’s start, at last, with a simple, testable definition of what these kinds of ideas actually are. Waterside Hypotheses of Human Evolution: Assert that wading, swimming and diving for food have acted as an agency of selection in the evolution of human beings more than it has in the evolution of our ape cousins both before (and hence causing) the split between these lineages and after. It notes that even very slight levels of selection can still result in profound and rapid phenotypic changes.
BROKEN EAR DRUMS
The last of the sea nomads
by Johnny Langenheim / 17 September 2010
Diana Botutihe was born at sea. Now in her 50s, she has spent her entire life on boats that are typically just 5m long and 1.5m wide. She visits land only to trade fish for staples such as rice and water, and her boat is filled with the accoutrements of everyday living – jerry cans, blackened stockpots, plastic utensils, a kerosene lamp and a pair of pot plants. Diana is one of the world’s last marine nomads; a member of the Bajau ethnic group, a Malay people who have lived at sea for centuries, plying a tract of ocean between the Philippines, Malaysia and Indonesia. The origins of the Bajau diaspora are recounted in the legend of a princess from Johor, Malaysia, who was washed away in a flash flood. Her grief-stricken father ordered his subjects to depart, returning only when they’d found his daughter. Over generations, the Bajau adapted to their maritime environment and, though marginalised, their knowledge was revered by the great Malay sultans, who counted on them to establish and protect trade routes. They are highly skilled free divers, plunging to depths of 30m and more to hunt pelagic fish or search for pearls and sea cucumbers – a delicacy among the Bajau and a commodity they have traded for centuries.
Since diving is an everyday activity, the Bajau deliberately rupture their eardrums at an early age. “You bleed from your ears and nose, and you have to spend a week lying down because of the dizziness,” says Imran Lahassan, of the community of Torosiaje in North Sulawesi, Indonesia. “After that you can dive without pain.” Unsurprisingly, most older Bajau are hard of hearing. When diving, they wear hand-carved wooden goggles with glass lenses, hunting with spear guns fashioned from boat timber, tyre rubber and scrap metal. The number of Bajau living on traditional lepa-lepa boats (narrow, high-prowed vessels, highly prized among the region’s coastal populations) is dwindling fast, however. Nomadism has always been at odds with the fixed boundaries of the nation state, and over the last few decades controversial government programmes have forced most Bajau to settle on land. Today, many live in stilt villages such as Torosiaje, though the settlement is unique in that it lies a full kilometre out to sea.
Ane Kasim and her son Ramdan spend six months at a time on their lepa-lepa, subsisting on whatever they can harvest from the reefs. At dusk, they gather with the other boats in the lee of a small island, beside a mangrove forest where the water is calm. They build small fires in the sterns, grilling crustaceans and boiling thin mollusc stews. Their connection with the natural surroundings is vital: “I love being at sea –fishing, rowing, just feeling everything, the cold, the heat,” Ane says. It’s not an easy life. Most lepa-lepa have rudimentary engines, but Ane can’t afford one. “When I go to Torosiaje, I have to row. We don’t have anything; my husband died from the cramp.” She means decompression sickness, or the bends. These days, those who can afford it dive using compressors. Air is pumped through a garden hose so divers can go deeper for longer – 40m or more. Unaware of the need to restrict their exposure to pressure, countless Bajau have ended up crippled or killed by deadly nitrogen bubbles in their bloodstream.
The practice continues, however, because it’s lucrative – especially when potassium cyanide is involved. Cyanide fishing was first introduced in the Philippines by Hong Kong fishing boats looking for reef species such as grouper and Napoleon wrasse to satisfy seafood restaurants’ rising demand for live fish. It quickly spread throughout the Coral Triangle, a bio-region that spans six south-east Asian countries and is home to the planet’s greatest diversity of marine species, including 76% of all known corals. Divers use plastic bottles to puff poisonous clouds at target species, stunning them and damaging the coral habitat. Today, the industry is worth upwards of $800m a year, according to research by WWF.
Torosiaje used to be flanked by teeming reefs; now there are only wastelands of broken coral, the legacy of years of dynamite and cyanide fishing. It’s a common story throughout the Coral Triangle – communities destroying the environment that sustains them, driven by voracious global markets. Thankfully, things are beginning to change. Charities such as WWF and Conservation International are helping create marine management programmes that encourage sustainability through no-fish zones and a return to traditional fishing methods. It is often the Bajau who pass on such programmes to local communities. Traditional Bajau cosmology – a combination of animism and Islam – reveals a complex relationship with the ocean, which for them is a multifarious and living entity. There are spirits in currents and tides, in coral reefs and mangroves. Such reverence and knowledge could be used to conserve rather than destroy.
Sir David Attenborough looks at the ‘aquatic ape / 12 and 19 April 2005
The hypothesis proposes that the physical characteristics that distinguish us from our nearest cousin apes – standing and moving bipedally, being naked and sweaty, our swimming and diving abilities, fat babies, big brains and language – all of these and others are best explained as adaptations to a prolonged period of our evolutionary history being spent in and around the seashore and lake margins, not on the hot dry savannah or in the forest with the other apes. The programmes explore the varieties of response to the theory, from when it was first proposed to the present day. Why it is seen by many as a very provoking idea and at the accumulating evidence of recent years that seems to be tipping the mainstream towards assimilating many of the AAH proposals. Programme two ends with dramatic new biological evidence suggesting that water-birthing was a very early human evolutionary adaptation.
The series starts [Real Media Format] by looking at the history of the AAH and other competing theories of human origins – and at the prevailing ideas about early human evolution in 1960 when Hardy first raised the tentative question: Was man more aquatic in the past? Programme one considers Raymond Dart’s Taung Child discovery and the ensuing savannah theory of human origins, as popularised by Robert Ardrey and Desmond Morris; the reaction to Hardy’s radical alternative and to Elaine Morgan’s bestseller: Descent of Woman.
The second programme looks at the evidence that has accumulated in the last 5 – 10 years which seems to be driving the anthropological herd inexorably down to the water’s edge. It includes reports on brain evolution, highlighting the essential fatty acids and nutrients that can only be sourced in the marine food chain; the global coastal migrations of early hominids, including major water crossings 1 million years ago; diving response and voluntary breath-control as semi-aquatic pre-adaptation for speech and some new and intriguing research findings that seem to indicate that water-births may be a very ancient human adaptation indeed.
Was man more aquatic in the past?
by Professor Sir Alister Hardy, FRS. The New Scientist, 17 March 1960
On 5 March I was asked to address a conference of the British SubAqua Club at Brighton and chose as my theme “Aquatic Man: Past, Present and Future”. I dealt little with the present, for Man’s recent achievements in the underwater world were so well illustrated by other speakers and by films. I ventured to suggest a new hypothesis of Man’s origin from more aquatic ape-like ancestors and then went on to discuss possible developments of the future. I did not expect the wide publicity that was given to my views in the daily press, and since such accounts could only be much abbreviated, and in some cases might be misleading, I gladly accepted the invitation of The New Scientist to give a fuller statement of my ideas. I have been toying with this concept of Man’s evolution for many years, but until this moment, which suddenly appeared to be an appropriate one, I had hesitated because it had seemed perhaps too fantastic; yet the more I reflected upon it, the more I came to believe it to be possible, or even likely. In this article I shall deal with this hypothesis; next week I shall treat of the future. Man, of course, is a mammal, and all the mammals have been derived, as indeed have also the birds but by a different line of evolution, from reptile ancestors that flourished more than a hundred million years ago, when the world was populated by saurians of so many different kinds which have long since become extinct These reptile ancestors in turn were derived from newt-like animals – amphibian creatures – which had only partially conquered the land and had to return to water to breed as do most of our salamanders and frogs of today. It is equally certain that these earlier amphibians were evolved from fish which, like those primitive lung-fish that still survive in certain tropical swamps today, had developed lungs with which to breathe. Some of these air-breathing fish were able to climb from the water on to the land.
This history of the emancipation of animal life from the sea is very well known. I repeat it only because it forms the background to another story, one that is not quite so familiar to those who are not trained as zoologists. At the same time as this conquest of the land was extending with continually improving adaptations to the new terrestrial life, we see (in the fossil record) a different act repeating itself again and again, first with the amphibians, next with the reptiles, and then with the mammals and indeed the birds as well. Excessive multiplication, over-population, shortage of food, resulted in some members of each group [Footnote: The amphibians went back only into freshwater (for certain physiological reasons) not into the sea.] being forced back into the water to make a living, because there was not enough food for them on the land. Among the reptiles I need only remind you of the remarkable fish-like ichthyosaurs, of the plesiosaurs, of many marine crocodile-like animals, and of turtles, not to mention water-snakes. Then, among the mammals of today we see the great group of whales, dolphins and porpoises, with the vestigial remains of their hind legs buried deep in their bodies, beautifully adapted to marine life; or again the dugongs and manatees belonging to an entirely different group. The seals are well on their way to an almost completely aquatic life, and many other groups of mammals have aquatic representatives which have been forced into the water in search of food: the polar bears, the otters (both freshwater and marine), various aquatic rodents, like water voles and the coypu, or insectivores like the water shrew: and, of course, we must not forget the primitive duckbilled platypus. There are, indeed, few groups that have not, during one time or another in the course of evolution, had their aquatic representatives: among the birds the penguins are supreme examples. The suggestion I am about to make may at first seem far-fetched, yet I think it may best explain the striking physical differences that separate Man’s immediate ancestors (the Hominidae) from the more ape-like forms (Pongidae) which have each diverged from a common stock of more primitive apelike creatures which had clearly developed for a time as tree-living forms.My thesis is that a branch of this primitive ape-stock was forced by competition from life in the trees to feed on the sea-shores and to hunt for food, shell fish, sea-urchins, etc., in the shallow waters off 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 shell fish, but becoming gradually more adept at swimming. Then, in time, I see him becoming more and more of an aquatic animal going farther 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. Let us now consider a number of points which such a conception might explain. First and foremost, perhaps, is the exceptional ability of Man to swim, to swim like a frog, and his great endurance at it. The fact that some men can swim the English Channel (albeit with training), indeed that they race across it, indicates to my mind that there must have been a long period of natural selection improving Man’s qualities for such feats. Many animals can swim at the surface, but few, terrestrial mammals can rival Man in swimming below the surface and gracefully turning this way and that in search of what he may be looking for. The extent to which sponge and pearl divers can hold their breath under water is perhaps another outcome of such past adaptation.
It may be objected that children have to be taught to swim; but the same is true of young otters, and I should regard them as more aquatic than Man has been. Further, I have been told that babies put into water before they have learnt to walk will, in fact, go through the motions of swimming at once, but not after they have walked. Does the idea perhaps explain the satisfaction that so many people feel in going to the seaside, in bathing, and in indulging in various forms of aquatic sport? Does not the vogue of the aqua-lung indicate a latent urge in Man to swim below the surface? Whilst not invariably so, the loss of hair is a characteristic of a number of aquatic mammals; for example, the whales, the Sirenia (that is, the dugongs and manatees) and the hippopotamus. Aquatic mammals which come out of the water in cold and temperate climates have retained their fur for warmth on land, as have the seals, otters, beavers, etc. Man has lost his hair all except on the head, that part of him sticking out of the water as he swims: such hair is possibly retained as a guard against the rays of the tropical sun, and its loss from the face of the female is, of course, the result of sexual selection. Actually the apparent hairlessness of Man is not always due to an absence of hair: in the white races it is more apparent than real in that the hairs are there but are small and exceedingly reduced in thickness: in some of the black races, however, the hairs have actually gone, but in either case the effect is the same: that of reducing the resistance of the body in swimming. Hair, under water, naturally loses its original function of keeping the body warm by acting as a poor heat conductor; that quality, of course, depends upon the air held stationary in the spaces between the hairs – the principle adopted in Aertex underwear. Actually the loss or reduction of hair in Man is an adaptation by the retention into adult life of an early embryonic condition; the unborn chimpanzee has hair on its head like Man, but little on its body. Whilst discussing hair it is interesting to point out that what are called the “hair tracts” – the directions in which the hairs lie on different parts of the body – are different in Man from those in the apes; particularly to be noted are the hairs on the back, which are all pointing in lines to meet diagonally towards the mid-line, exactly as the streams of water would pass round the body and meet, when it is swimming forward like a frog. Such an arrangement of hair, offering less resistance, may have been a first step in aquatic adaptation before its loss. The graceful shape of Man – or woman! – is most striking when compared with the clumsy form of the ape. All the curves of the human body have the beauty of a well-designed boat. Man is indeed streamlined.These sweeping curves of the body are helped by the development of fat below the skin and, indeed, the presence of this subcutaneous fat is again a characteristic that distinguishes Man from the other primates. It was a note of this fact in the late Professor Wood Jones’s book Man’s Place among the Mammals (p. 309) that set me thinking of the possibility of Man having a more aquatic past when I read it more than thirty years ago. I quote the paragraph as follows: “The peculiar relation of the skin to the underlying superficial fascia is a very real distinction, familiar enough to everyone who has repeatedly skinned both human subjects and any other members of the Primates. The bed of subcutaneous fat adherent to the skin, so conspicuous in Man, is possibly related to his apparent hair reduction; though it is difficult to see why, if no other factor is invoked, there should be such a basal difference between Man and the Chimpanzee.”
I read this in 1929 when I had recently returned from an Antarctic expedition where the layers of blubber of whales, seals and penguins were such a feature of these examples of aquatic life; such layers of fat are found in other water animals as well; and at once I thought perhaps Man had been aquatic too. In warm-blooded water animals such layers of fat act as insulating layers to prevent beat loss; in fact, in function they replace the hair. Man, having lost his hair, must, before he acquired the use of clothing, have been subjected to great contrasts of temperature out of water; in this connection it is interesting to note the experiments carried out at Oxford by Dr. J. S. Weiner, who showed what an exceptional range of temperature change in air Man can stand, compared with other mammals. Man’s great number of sweat glands enable him to stand a tropical climate and still retain a large layer of fat necessary for aquatic life. This idea of an aquatic past might also help to solve another puzzle which Professor Wood Jones stressed so forcibly, that of understanding how Man obtained his erect posture, and also kept his hands in the primitive, unspecialized, vertebrate condition; for long periods, the hands could not have been used in support of the body as they are in the modern apes, which have never mastered the complete upright position. The chimpanzee slouches forward with his body partly supported by his long arms and with his hands bent up, to take the weight on the knuckles. Man must have left the trees much earlier; in all the modern apes the length of the arm is much longer than that of the leg. In Man it is the reverse. The puzzle is: how in fact did Man come to have the perfect erect posture that he has – enabling him too run with such ease and balance? Some have supposed that he could actually have achieved it by such running, or perhaps by leaping, but this does not seem likely. Let me again quote from Wood Jones, this time from his book The Hallmarks of Mankind, 1948, p. 78: “Almost equal certainty may be attached to the rejection of the possibility that he ever served an apprenticeship as a specialized leaper or a specialized runner in open spaces. But it is by no means so easy to reject the supposition that he commenced his career of bipedal orthograde progression as what might be termed a toddler, somewhat after the fashion followed in some degree by the bears.” It seems indeed possible that his mastery of the erect posture arose by such toddling, but performed in the water, like children at the seaside. Wading about, at first paddling and toddling along the shores in the shallows, hunting for shellfish, Man gradually went farther and farther into deeper water; swimming for a time, but having at intervals to rest – resting with his feet on the bottom and his head out of the surface: in fact, standing erect with the water supporting his weight. He would have to raise his head out of the water to feed; with his hands full of spoil he could do so better standing than floating.
It seems to me likely that Man learnt to stand erect first in the water and then, as his balance improved, he found he became better equipped for standing up on the shore when he came out, and indeed also for running. He would naturally have to return to the beach to sleep and to get water to drink; actually I imagine him to have spent at least half his time on the land. Tied up with his method of assuming the erect position is the problem of the human hand. Let me quote again from Wood Jones (ibid., p. 80):In the first place, it seems to be perfectly clear that the human orthograde habit must have been established so early in the mammalian story that a hand of primitive vertebrate simplicity was preserved, with all its initial potentialities, by reason of its being emancipated from any office of mere bodily support. Perhaps the extreme structural primitiveness of the human hand is a thing that can only be appreciated fully by the comparative anatomist, but some reflection on the subject will convince anyone that its very perfections, which at first sight might appear to be specializations, are all the outcome of its being a hand unaltered for any of the diverse uses to which the manus of most of the ‘lower’ mammals is put. Man’s primitive hand must have been set free to perform the functions that it now subserves at a period very early indeed in the mammalian story.” Man’s hand has all the characters of a sensitive, exploring device, continually feeling with its tentacle-like fingers over the sea-bed: using them to clutch hold of crabs and other crustaceans, to prise out bivalves from the sand and to break them open, to turn over stones to find the worms and other creatures sheltering underneath. There are fish which have finger-like processes on their fins, such as the gurnards; they are just such sensitive feeling organs, hunting for food, and they, too, have been known to turn over stones with them while looking for it. It seems likely that Man learnt his tool-making on the shore. One of the few non-human mammals to use a tool is the Californian sea-otter, which dives to the bottom, brings up a large sea-urchin in one hand and a stone in the other, and then, whilst it floats on its back at the surface, breaks the seaurchin against its chest with the stone, and swallows the rich contents. Man no doubt first saw the possibilities of using stones, lying ready at hand on the beach, to crack open the enshelled “packages” of food which were otherwise tantalizingly out of his reach; so in far-off days he smashed the shells of the sea urchins and crushed lobsters’ claws to get out the delicacies that we so much enjoy today. From the use of such natural stones it was but a step to split flints into more efficient tools and then into instruments for the chase. Having done this, and learnt how to strike together flints to make fires, perhaps with dried seaweed, on the sea-shore, Man, now erect and a fast runner, was equipped for the conquest of the continents, the vast open spaces with their herds of grazing game. Whilst he became a great hunter, we know from the middens of mesolithic Man that shell fish for long remained a favourite food. In such a brief treatment I cannot deal with all the aspects of the subject: I shall later do so at greater length and in more detail in a full-scale study of the problem. I will just here mention one more point. The students of the fossil record have for so long been perturbed by the apparent sudden appearance of Man. Where are the fossil remains that linked the Hominidae with their more ape-like ancestors? The recent finds in South Africa of Australopithecus seem to carry us a good step nearer to our common origin with the ape stock, but before then there is a gap. Is it possible that the gap is due to the period when Man struggled and died in the sea? Perhaps his remains became the food of powerful sea creatures which crushed his bones out of recognition, or could his bones have been dissolved, eroded away in the tropical seas? Perhaps, in time, some expedition to investigate tropical Pliocene (coastal) deposits may yet reveal these missing links. It is interesting to note that the Miocene fossil Proconsul, which may perhaps represent approximately the kind of ape giving rise to the human stock, has an arm and hand of a very unspecialized form: much more human than that of the modern ape. It is in the gap of some ten million years, or more, between Proconsul and Australopithecus that I suppose Man to have been cradled in the sea. My thesis is, of course, only a speculation – an hypothesis to be discussed and tested against further lines of evidence. Such ideas are useful only if they stimulate fresh inquiries which may bring us nearer the truth.