Human Evolution - the Aquatic Ape Hypothesis Content from the guide to life, the universe and everything

Human Evolution - the Aquatic Ape Hypothesis

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Creationists sometimes deride the weakness of the theory of evolution. They point out that every time a new piece of evidence is found, or a better explanation of existing evidence is developed, the theory changes. Oddly, they see this as a bad thing. Scientists, on the other hand, can point to exactly the same facts as evidence that they are open-minded and willing to consider alternative ideas.

However, the scientific establishment is not the haven of open-minded free-thinkers it may wish to portray itself as. The following theory has been proposed as an alternative to the accepted theory of human evolution. While this alternative gives no succour whatever to the Creationists, it does serve as a reminder that the Evolutionist side is not without its weaknesses.

The Conventional Theory of Human Evolution

Mainstream evolutionary theory has it that man's ancestors were arboreal apes who descended from the trees in Africa and took up a quite different existence on the savannahs. Among other adaptations, this led to man's ancestors adopting an upright posture to allow them to see greater distances to spot prey and predators. This view of man's development is generally accepted by the scientific establishment and is rarely questioned from within.

An Alternative Theory

A British scientist named Sir Alister Hardy presented an alternative theory in March, 1960. He presented it to a meeting of the British Sub Aqua Club in Brighton, which might seem odd, but the title of the talk was 'Aquatic Man - Past, Present and Future'. Hardy's most interesting ideas were firmly rooted in man's aquatic past. His view was that man had certainly originated in trees, but had gone directly to an almost amphibious existence, wading and swimming in rivers, lakes or the ocean.

The Evidence of Our Bodies

If we examine the human body, there are a number of adaptations that seem out of place on a savannah-dwelling animal, but make much more sense if you consider them as adaptations to a primarily water-based existence.

We have relatively hairless bodies compared to all the other great apes, which are completely covered in hair. Very few mammals are as completely hairless as humans, and most of those that are live in an aquatic environment. Also, what little hair we have does not sprout randomly, but is aligned to direct water to our midline, minimising drag.

Mammals have many mechanisms for shedding excess heat, including panting, insulating layers of fur - camel fur keeps the heat out - and bathing in cooling mud or water. Humans lose heat primarily by sweating. This costs the body vital salt which would be a problem for a plains-dwelling animal, but not for one that lived close to or in the sea. Crying salt tears is a unique human trait, which may have evolved as a way to shed excess salt.

Humans are the only terrestrial animals that can voluntarily hold their breath at will. The only other mammals that can do this are all aquatic or semi-aquatic, such as otters, seals, whales, dolphins, hippos and so on.

Humans, unlike other apes, have a descended larynx just like seals. This makes gulping large amounts of air at one time very easy. This is useful for underwater fishing, in that it allows a very quick 'top-up' of the lungs between or after dives.

Humans are the only apes to have subcutaneous fat. Like seals and whales, this is insulation (blubber) from heat loss under water. The fat is bonded to the epidermis from underneath, which is unusual in the ape species but not unusual in sea mammals.

Human babies are born fat and with the instinctual ability to swim and hold their breath under water. This is highly characteristic of an animal that has evolved by the sea, and fat babies who can swim would not be very useful on the savannah.

It is possible that humans became bipedal because it was useful for keeping the head above water when swimming and coming up for air. There is a great deal of debate over the origins of man's bipedal gait - enough to fill an entry alone. However, suffice to say here that there is enough uncertainty in the 'mainstream' explanations to allow for alternatives such as this.

Not Respectable

This theory of man's origins is not generally accepted. Worse than that, it is not even being actively researched by many experts in the field. It has been the subject of a number of popular books, most notably those of Elaine Morgan, author of The Aquatic Ape, The Scars of Evolution and The Aquatic Ape Hypothesis. Nevertheless, this theory is almost entirely dismissed as being fringe at best, and crackpot at worst. In his book Darwin's Dangerous Idea, Daniel Dennett observes:

When I have found myself in the company of distinguished biologists, evolutionary theorists, paleoanthropologists... I have often asked them just to tell me, please, exactly why Elaine Morgan must be wrong... I haven't yet had a reply worth mentioning, aside from those who admit, with a twinkle in their eyes, that they have often wondered the same thing.

So Is It True?

The aquatic ape theory of human development does not definitively answer the existing questions of human evolution. On the other hand, it does pose some difficult questions of its own. It is not so much a coherent whole as a selection of scattered observations about odd features of comparative physiology and fossil evidence. But its value lies in its ability to pinpoint and expose weaknesses in the generally accepted 'ape on the savannah' theory, and the scientific establishment's unwillingness to address those questions seriously does not do it any credit. This is especially important when the same scientific establishment is, on the one hand, trying to stem the tide of Creationist educationalists and, on the other, suffering a credibility gap with the public.

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