Humans differ from all the other apes in a wide variety of ways. A naked skin, walking
on two legs, and the ability to speak are striking examples. Darwin’s theory of natural
selection implies that these differences must have been caused by some change in
habitat or life-style undergone by our ancestors, and not by those of the chimpanzee.
The question is, what change?
For most of the last century the accepted answer was that proposed by Raymond Dart
- that the apes’ ancestors remained in the trees while our own ancestors moved out
onto the grasslands, where shortage of fruit and leaves compelled them to become
Professor Sir Alister Hardy, F.R.S., when he was a young Oxford marine biologist,
had noted that a fat-lined hairless skin was more commonly found in aquatic mammals
than in terrestrial ones, and conceived that the crucial change might have been a
shift to a more watery habitat. In 1960, he published an article in New Scientist
entitled “Was Man more aquatic in the past?”. He was sternly rebuked for airing such
bizarre views on a subject outside his speciality. Nothing more was heard of the
idea for twelve years.
In 1972 I began writing a book, The Descent of Woman, appealing for parity of esteem
between the sexes. I was reacting against the strongly macho version of human emergence
outlined by Dart , and popularised by writers like Robert Ardrey. The only alternative
paradigm on offer was Hardy’s aquatic suggestion briefly mentioned in Desmond Morris’s
best selling book The Naked Ape. I found it instantly convincing and incorporated
it into my narrative.
From that point on I continued to promote the idea, with Alister’s consent and approval.
He himself published nothing further on the subject except one article in 1977 and
a preface to my second book in 1982.
The Descent of Woman became a popular best-seller, but the scientific community,
naturally enough, reacted with contempt. They had strong reasons for doing so. I
had no scientific qualifications, the book was politically motivated, the style was
confrontational and I wrote it too fast to have done much research. Moreover, the
concept of the ape that moved to the plains had been unquestioned for over forty
Another reason for rejection was that evolutionary theory had become almost exclusively
the domain of palaeontologists, based on the study of fossilised skeletons. Hardy’s
case was based on studying and comparing the anatomy of extant species - the soft
tissues as well as the bones and teeth. That had also been Darwin’s method. A number
of these features - such as the loss of body hair, subcutaneous fat, greatly diminished
sense of smell, descended larynx, etc – had never been studied in detail by palaeontologists
because they did not fossilise.
There are a number of aquatic mammals - including whale, dolphin, dugong, hippopotamus,
manatee - with hairless skins. Others like walrus and sea elephant are well on the
way to becoming hairless. Many of them also have thick layers of subcutaneous fat.
Some anatomists have made the case for believing that a coat of hair outside the
skin is clearly the best means of regulating temperature in air, but in water a naked
skin lined with fat is more efficient. Humans are the only primates to have evolved
Then there is speech. No other mammal on sea or land has learned to speak. But the
precondition for being able to speak is acquiring voluntary control over breathing
. Breathing is, in most animals, as involuntary as the processes of digestion or
the beating of the heart. But all diving mammals have voluntary breath control. I
know of no terrestrial mammal that has acquired it. That’s why the laboratory rat,
which has been trained to do so many clever tricks in order to gain a reward or avoid
a punishment, cannot be trained to obtain a reward by squeaking for it.
It has been pointed that no aquatic mammal habitually walks upright in the way humans
do. (No non-aquatic mammal does, either.) But Hardy pointed out that an ape walking
down a beach and into the sea would very soon have to rise up and proceed on two
legs in order to keep its head above water. And in fact, wading in water is the only
situation in which apes and monkeys invariably resort to walking on two legs.
These arguments might not add up to a conclusive proof that Hardy got it right. But
they are not crackpot arguments. They are speculations based on observation and reason,
and quite as firmly rooted in Darwin’s theories of how evolution works as any other
explanation that has been advanced.
The onus of proof
I was informed of a time-honoured rule of procedure which lays down that when a prevailing
belief is challenged in this way, it does not need to be defended. The onus is on
the challengers to submit their own beliefs to criticism and questioning, and stand
ready to answer the objections. I would be happy to take part in such an exchange
of views but the opportunity has never arisen. It’s been stated a score of times
that the aquatic theory was in fact carefully evaluated by experts in Hardy’s day
and found to be flawed. But no-one has ever disclosed the time, the place, the names
of the investigators, or their reasons for rejecting it. The unspoken assumption
seems to be that the aquatic suggestion is, like the tales of the yeti and the UFO,
self-evidently too absurd to deserve even to be debated.
This attitude has persisted despite new strands of evidence that have emerged since
the seventies and appear to lend credence to Hardy’s idea.
There was, for example, the news about swimming babies – the revelation that a human
baby is not afraid of water if introduced to it early enough, and can in fact learn
to swim before it can learn to walk.
Then there was a growing interest in dietetics, and in the revelation that the relative
amounts of Omega 3 and Omega 6 in the sea food chain were in precisely the ratio
most conducive to the kind of rapid brain growth experienced by our ancestors.
Intensive attempts to teach apes to speak confirmed that they could readily use and
understand sign language, and all that prevented them from talking was their lack
of voluntary breath control. There was a growing conviction that the rapid dispersal
of hominid ancestors from Africa to Asia and the off-shore islands had been accomplished
by a migration along the continental coastlines, rather than travelling overland.
My suggestion in 1982 that elephants may have descended from aquatic mammal ancestors
gained acceptance. The television footage of gorillas wading bipedally in the swamps
of the Congo supported the idea that wading behaviour could have been the fore-runner
of our own bipedalism. The aquatic theory collected supporters, in print and online,
though never in any of the peer-reviewed journals.
Despite all that, the solid obstacle remained for many years: : the fossilised bones
of our predecessors, and the apparently unshakable belief that they lived and died
on the open plains. But that too began to change.. A closer study of the flora and
fauna found in the same deposits as the hominid fossils proved that the fossilised
bones of mammals and the fossilised pollen of plants belonged to species that were
known not to flourish in grassland environments. Sites that are now savannah were
not savannah at the time when the bones were deposited there. It was concluded, and
is now accepted, that there were proto-hominids walking on two legs in Africa before
the savannah ecosystem came into existence. Professor Philip Tobias, for decades
one of best-known and most influential proponents of the savannah hypothesis, announced
that it was time to abandon it and think again. “We are back to Square One”, he said.
Closing the ranks
The question, “Why are we so different?” was once again wide open. There might be
good reasons for rejecting AAT but the favourite one - “because we’ve got a better
answer” - was no longer operative.
Professor Lee Berger was swift to sum up the immediate reaction: “Just because the
savannah theory was wrong , that doesn’t mean the aquatic idea is right.” That is
certainly true. There may be a third paradigm that nobody has thought of, which would
throw a flood of light on the whole question. As yet, though, nothing of that kind
has been unveiled.
Another response was to say that nothing has changed, because when scientists used
the term savannah , they had always envisaged a landscape containing wooded areas,
and rivers flanked by gallery forests, and lakes. One difficulty there is that whenever
they attempt to explain anything about human anatomy, they still tend to attribute
it to the rigours of life on the open plains. The other difficulty was: If our ancestors,
like the ancestors of the chimpanzees, continued to live in and around the trees,
why would that shared habitat cause them to split apart into two species so dramatically
different from one another?
Up to the present the conventional wisdom has officially prevailed, and the aquatic
theory remains officially beyond the pale. But it has not gone away. It makes good
sense to a lot of people. The Internet has kept it alive, and since Tobias’s declaration
a few other well-known figures have suggested that it should not necessarily be ruled
out. Sir David Attenborough presented an open-minded accounts of the history of it
on BBC radio, and Professor Daniel Dennett wrote in his book Darwin‘s Dangerous Idea:
“During the last few years, when I have found myself in the company of distinguished
biologists, evolutionary theorists, palaeoanthropologists, and other experts, I have
often asked them just to tell me, please, exactly why Elaine Morgan must be wrong
about the aquatic theory. I haven’t yet had a reply worth mentioning, aside from
those who admit, with a twinkle in their eyes, that they have also wondered the same
Effects of the boycott
The policy of “We don’t wish to talk about that” makes for a quiet life in academia,
but has its disadvantages.
One is that those with an active interest in AAT - and the numbers are growing all
the time - find themselves virtually in an intellectual ghetto. Online newsgroups
tend to devote their energies to internal differences of opinion - whether the first
venture was into salt water or fresh, and whether it happened before, or during,
or after the split between hominids and chimpanzees. Good questions - but the more
we confine ourselves to pursuing them, the easier it is for others to depict us as
a kind of inward-looking cult. There is no cult. There is no Authorised Version.
I’ve sometimes been asked: “What’s the message? What is it you are asking us to believe?”
Here it is:
“No agreed explanations have yet been arrived at concerning the origin of any of
the physiological hallmarks of mankind. They must have been caused by some factor
in their early environment. We don’t know what it was, but a waterside habitat is
one tenable hypothesis.”
There are disadvantages for the orthodox too. They find there are some areas, like
nakedness, where the aquatic case seems particularly persuasive, and that makes it
difficult to discuss them without at least some reference to it. A quick look at
the record reveals that in many universities it is never discussed at all. In fact
there is a distinct trend towards publishing less and less about the Darwinian question:
“What was it that caused these distinctively human characteristics to be selected
In the year when scientists are celebrating the 150th anniversary of The Origin of
Species, they are eager to apply the concept of natural selection to all the rest
of the living world. It is sad and ironic that when it comes to the human race they
seem to be saying “Oh but we’ve moved on from that. That’s something we don’t talk
about any more.”