This theory, of course, leaves much unexplained. None of the most prominent physical characteristics of humans would be an obvious advantage in this new environment: a huge grassed plain filled with fierce and fast predators.
Of all the primates which lived in the declining forests only one, our ancestor, stood up from its four limbs and moved upright on to the savanna. Why?
Under the same pressure of population, no other apes or monkeys also reacted in this way. Why?
The environment of the savanna, with its lions, hyenas and other voracious carnivores, was truly hostile. Yet we are asked to believe that some type of proto-intelligent ape entered it, having given up its normal, and rather fast, running on four limbs for an upright gait which would slow it down. One would expect all of these foolhardy apes to have been rapidly wiped out.
From an animal’s point of view, running on two limbs is entirely foolish; much of the energy expended in activity is used in simply holding the body upright rather than in propelling it forward at speed. It is a very inefficient means of locomotion.9 Something of a problem when being chased by predators seeking food.
Why did any of our ancestors change? How could the force of natural selection on the open savanna cause such an alteration in structure?
The answer is, it cannot.
Why Are There Human Beings?
How are we different from other primates, from apes and orangutans, for instance? Obviously we have a larger brain and the power of speech. We also have bodily differences: we are not covered with fur and we walk upright on two legs. But those are just the immediately apparent distinctions. In fact, there are hundreds of differences.
Almost unbelievably, science does not have any viable explanation for the evolutionary development of any of these crucial characteristics. Certainly scientists have tried: theories have been advanced to account for them and, at times, these theories have been deemed sufficiently competent to become fixed in the evolutionary ‘mythology’. But not for long. All the explanations have soon been found wanting. Too many human traits seem impossible to explain, and so scientists, unable to clarify the issue, have generally shied away from the difficulties such ignorance presents.
Biologists, in particular, have called attention to those aspects of the human body which seem to have defied evolutionary process. The growth of the brain, for example – not seen in any of the apes or other primates – the loss of bodily hair, a unique mode of breathing which also allows speech, and a distinctive mode of sexual behaviour.
The size of the brain appears to have steadily increased: from the chimp-sized brain of Lucy; the 440 cubic centimetres (26.8 cubic inches) or so brain of Australopithecus; around 650 cubic centimetres (39.6 cubic inches) for what is considered to be early true man; 950 (52.9) to 1,200 (73.2) for Homo erectus; 1,350 (83.3) as an average for modern man, Homo sapiens. This increase in brain size has led to an increase in head size.
This growth in head size has meant the need for considerable bodily adaptation from ape-like creature to human-like creature simply in order that a female can give birth to an infant with such a large head. For this reason, a human mother has a pelvis of a very different shape from that of an ape. And so important is this increase in brain size that, in modern man, for the first year after birth, the brain continues to grow so much that it effectively doubles in size. A woman could not give birth if the brain were to be fully developed from the beginning.
The loss of hair, of the thick body fur which is so evident in apes, is also something of a curiosity with modern humanity. This hair would protect the body from the sun’s heat and from the cold temperatures at night. How would living in the savanna – hot by day and often very cold at night – cause this trait of hairlessness to be developed by natural selection?
Another enigma is our ability to speak. This is a function of our peculiar mode of breathing which is quite different from that of apes, or, in fact, from any other animal alive upon this earth. It is unique to humans.
A New Look at Evolution
It is salutary to consider that while these changes occurred in some of the apes – those which apparently developed into humans – they did not occur in any other. The other apes have continued without much evolutionary development for several millions of years, perhaps much longer. Why should the evolutionary forces choose only one species on which to exercise their art? This remains unexplained.
By standard thinking, for any evolutionary or adaptive change to take place two factors must be present: firstly, the change must give an immediate advantage to the creature within its environment. It is not a viable argument to suggest that the creature struggled on, hoping perhaps that in several hundred thousand years all would become easier.
Secondly, the animal and its breeding population need to be isolated from others of its species so that there is no further opportunity for any exchange of genetic coding. This isolation is usually by means of some physical boundary such as a desert, a mountain or a sea. These boundaries prise apart, and keep apart, two groups which originally were one. The savanna does not fulfil these conditions.
Humans are mammals: highly specialized, certainly, but sharing many bodily features in common with others. Yet we humans are unique among land-dwelling mammals in that we can breathe with equal ease through our nose or our mouth. Similarly unique is our inability to breathe and drink at the same time. This is because of a special feature we have called a ‘descended larynx’.10
Mammals – apart from ourselves – all have one channel linking the nose with the lungs, the windpipe. They also have another, the gullet, which connects the mouth with the stomach. These two channels are kept separate. Such animals can therefore drink and breathe at the same time.
This occurs because the mouth and nose are separated by the palate, the forepart of which is the bony roof of the mouth. The rear part is comprised of soft tissue. In all terrestrial mammals, apart from man, the windpipe passes up through the palate by way of a circular sphincter muscle. Thus, normally, the windpipe is above the mouth cavity and is connected only to the nose.
However, under certain conditions, the sphincter muscle can relax and allow the top of the windpipe – the larynx – to descend into the mouth cavity. This lets air from the lungs be either expelled through the mouth, or drawn in. It is this feature which allows, for example, a dog to bark.
Following the barking, the windpipe rises upwards again and the sphincter muscle tightens, thus once again establishing the separation between the air and food channels.
However, in humans the windpipe has no connection with the top of the mouth and is in the throat, beneath the root of the tongue. It is this condition which is termed the ‘descended larynx’. We have no sphincter in the palate to keep the windpipe and gullet separate. Rather, the rear of our palate is open, allowing both air and food to enter either our lungs or our gullet.
This is, of course, a potentially hazardous arrangement. A design fault in natural selection. It makes swallowing a complex action since we have to ensure that food or drink does not enter the windpipe rather than the gullet.
If, for some reason, our control breaks down – through illness, accident or intoxication – we might, for example, suffocate in our own vomit. In fact, the accidental choking on food is a rather common cause of death in humans.
How this anomalous biological construction evolved by natural selection – or any other means, for that matter – between the forest and the savanna is a complete mystery to biologists.11 While all the experts are agreed on its singular character, none has come up with any viable explanation for its origins. But we possess such a feature; it developed, therefore at some point in our evolutionary history we must have needed it. It must have given us an advantage in our environment.
What environment could that possibly be?
The case of the proboscis monkey provides a clue. This monkey lives in the coastal mangrove swamps of Borneo. While it normally resides in the trees, when it desc
ends it more often than not steps into water rather than on to dry land. Accordingly, these monkeys have learned to swim well and for long distances.
In shallow water they will pick themselves up from four limbs and wade in on two legs only. They are also known to exit the water on to dry land while remaining upright. The ability of these modern monkeys to walk even a short distance upright on two feet confers an immediate advantage in their partly aquatic environment.12
This example points to a possible solution to the problem of the enigmatic features of the human body.
An Aquatic Life
While no other terrestrial mammals have the descended larynx, there are other mammals which do possess it. But they are only those which live in the sea or lakes; mammals such as seals, whales, dugongs and sea-lions. They are all animals which need to dive for long periods beneath the surface of the water.
While the descended larynx confers no advantage to terrestrial creatures, it does give a distinct advantage to those which are aquatic. With the means of breathing through the mouth, the animal can inhale or exhale a considerable volume of air in a short time. This is important when surfacing for a moment before a dive. It also allows the animal to exhale very slowly under fully conscious control.
This latter is another, related characteristic which we share with aquatic animals: conscious control over the lungs giving control over breathing. An example of this is seen with the Aboriginal musicians of Australia who employ a disciplined circular breathing pattern to play upon the didgeridoo. A similar example is seen with monks who use complicated breath control for their Gregorian chants. For other terrestrial mammals, breathing is as uncontrollable as the beating of their heart.13
In us this has produced something even more unique: the ability to speak. This conscious control of the breath is the means by which we can produce the wide and subtle range of sounds which speech depends upon. Why this should be a gift granted only to humans is a mystery which so far has no solution.
Our face-to-face mode of sexual copulation too is more akin to the aquatic life. Land mammals do not practise this mode of sexual relations but it is the norm with whales, dolphins, sea-otters and others.
Our mode of perspiration is also as unique to humans as is walking on two legs or the ability to speak. It is a surprisingly inefficient mechanism: it wastes water and salt, is slow to begin – leading to the danger of sunstroke – and slow to respond when the water and salt levels of the body become dangerously depleted.
To allow a salt deficiency to continue is to court trouble. A human body, sweating heavily, can expel all its salt in a mere three hours. This leads to the onset of violent cramps and, if not quickly treated, to death.
It is difficult to see how this wasteful system could have evolved in the African savanna where water and salt loss would have posed a frequent and serious problem.14
Humans have a prominent layer of fat just under their skin. Indeed, it comprises over 30 per cent of all our bodily fat. This is absent in other terrestrial primates. But this fat layer is the norm amongst aquatic mammals: whales, seals and dolphins all have it.
Biologists who have studied this layer note that it provides an excellent insulation against loss of body heat – but only in the water. In the air it is much less effective than the normal terrestrial design of a layer of body fur.15 For all those scientists who study the evolution of human features, the existence of this fat layer continues to be enigmatic.
In the face of this evidence it is very unlikely that the savanna was the defining environment for evolving mankind.
For natural selection to favour such a naked ape as a human being, the best environment would be a life in water. With water, the ability to stand and walk upright on two legs would confer an immediate advantage: the ape would avoid its land-based enemies and it would be able to survive by breathing above the surface. As the biologist and writer Elaine Morgan notes, walking upright on land gave few immediate advantages and required thousands of years for it to become efficient. On the other hand, ‘Walking erect in flooded terrain was less an option than a necessity.’16
Where Could an Aquatic Ape Have Developed?
Where could this aquatic environment have been? There are many theories of African origin. And it is in Africa, according to the orthodox theory, that the oldest traces of mankind have been found. But it seems that we could not have developed in Africa, or, at least, on the mainland of it. This is indicated by the genetic ‘baboon marker’17
In 1976 three American cancer researchers investigating a virus carried by baboons made a startling discovery. In the distant past this lethal virus had caused a veritable plague amongst the primate population of Africa. It was an extremely infectious virus which caused a fatal disease. To survive it, primates evolved a genetic sequence which served to oppose its ravages. These researchers found that while the virulence of the virus had long disappeared, the protective genetic sequence remained. It was present in every primate of African origin. It was not present in any primates from elsewhere, from Asia or South America, for instance.18
The existence of this genetic sequence – the ‘baboon marker’ – could then comprise an indication of African origin. Checking, then, the genetic structure of man, the scientists found an absence of this sequence. They thus concluded that this was a sound indication that man’s origins were not to be found in Africa: they suggested Asia.
Elaine Morgan thought that this suggestion was unnecessary. She began looking for a region in Africa where apes might have left the jungles and moved into the water. And where, millions of years later, they might have moved back to the land.
Now it is unlikely that these moves were made deliberately: that an ape left its comfortable tree and stood in the water thinking that in a few million years some descendants would love it. Or that a comfortably adapted aquatic ape climbed out of the water – confronting the dangers of sunburn and new predators – and consoled itself with the thought that it all might become easier a million or more years down the line.
The most probable cause of these changes is that the environment altered. No land is totally stable and the great African Rift Valley, stretching from Tanzania to Ethiopia, is less stable than most. Paradoxically, this instability is important. It would foster a need for any resident species to adapt or die. And there is one particular part of Africa where these changes were just as the scenario requires.
Geologists have found that around 7 million years ago an inland sea became established in the northern Afar region in Ethiopia.19
The sea swept into this forested area and, in time, this water became trapped. Its entrance to the Red Sea and the Gulf of Aden was blocked by geological movements which isolated the Afar sea from the outside. After millions of years it gradually dried up to leave the salt plain, thousands of feet thick, which we see today.20 To the east of this vast dry salt plain is a mountainous region known as the Danakil Highlands. When the sea was in place this was a forest-covered island.21
Elaine Morgan concluded that the conditions of isolation were thus fulfilled: certain apes, isolated in this sea and on this island could begin their unique development into Homo. And, as they were isolated in this way, the baboon virus would not have reached them, thus explaining why humans lack the genetic ‘baboon marker’.22 In this region, the apes would have been driven into the water as the seas rose, and, millions of years later, driven back to land as the seas receded.
Consequently, it is in this area that fossils could usefully be sought, fossils which might provide archaeological support for the biological arguments. In fact, it has received recent attention and looks set to receive much more. In December 1995 a group of scientists from Italy and Eritrea were exploring what is now the salty Danakil Desert. They discovered part of a skull, part of a pelvis and a fingerbone which they dated at around 2 million years ago. These
The Danakil Desert and Highlands: showing the possible Danakil ‘island’.
are the first human bo
nes ever found in the region. ‘We are,’ said geologist Ernesto Abbate of the University of Florence, ‘just at the beginning.’23
It was in the desert further south of this region that Johanson found both Lucy and, later, a large group of human-like fossils comprising at least thirteen individuals who seemed to have drowned together.
Whatever Lucy’s true place in human or primate ancestry, could she be associated with an aquatic environment?
It was found that Lucy’s knees had not fully developed and could not lock in the modern manner: walking or standing would have been uncomfortable. As we have mentioned, the structure of her bones makes it likely that she may well have spent most of her time climbing trees. Many experts in the field support this position despite the well-publicized image of Lucy as queen of the savanna.24
All members of her species, according to Richard Leakey, could comfortably walk upright only for short periods.25 But that is on dry land. Such movement would not be a problem in water where much of her body weight would be supported. Lucy’s feet were never found, but those of other Australopithecus individuals proved proportionally much larger than ours, wider, with longer toes. Good for swimming and hanging in trees; bad for walking.
The site where Lucy was found suggests an affinity with water. It seems to have been the swampy edge of a lake, perhaps wooded. Her bones lay amongst remnants of crabs’ claws, together with crocodile and turtle eggs. Her bones were not attacked and scattered by any predators, which might indicate that she died by drowning. Of course, the savanna supporters argue that she was simply visiting the swamp to obtain water. But was she? Why could she not have lived in and about the water itself?
Studies of primitive contemporary cultures have shown that, in Africa, no land-dwelling humans choose to live at the edge of a lake or water-hole. The reason is that this locality is frequented by predators such as lions and hyenas which wait there to capture prey rendered vulnerable while drinking. This would not be a safe environment for proto-humans to live and raise children. But if, like the proboscis monkeys, these primitive creatures lived in the trees and swamps themselves, they would be protected from these predators.