The Aquatic Ape: Fact or Fiction
The only serious academic investigation into the plausibility of the so-called "aquatic ape hypothesis" in 42 Years
Proceedings from the Valkenburg Conference. Published by Souvenir Press. (1991) 369 pages. ISBN 0 285 63033 4 (Currently out of print)

Aquatic Ape: Fact or Fiction?


Valkenburg 1987

In Valkenburg, in the hilly southern part of the Netherlands, above limestone caves in which fossils like the Mosasaurus bear witness to a former marine environment, a conference, organised by the European Sociobiological Society and the Dutch Association of Physical Anthropology, was held in August 1987. Its aim was to evaluate the pros and cons of Sir Alister Hardy's daring idea about the Aquatic Ape, a presumed early ancestor of humans.

So begins the published book "Aquatic Ape Fact or Fiction" which remains the only serious academic work to properly evaluate the AAH in a serious and scientific way. (The other paper which is often cited as the AAH-killer is John Langdon's 1997 JHE paper about 'Umbrella hypotheses and parsimony.') 22 participants went to the Dutch town of Valkenburg to try to come up with some kind of a official statement about the theory.

The supporters of the AAH were looking for some kind of vindication of the theory, the opponents were looking for some kind of final rebuttal. Both would be disappointed but, it has to be said, that those attracted to the AAH would have been the more disappointed of the two.

So what did they decide?
The key sentence in the concluding epilogue for the whole conference was this: "
Our general conclusion is that, while there are a number of arguments favouring the AAT, they are not sufficiently convincing to counteract the arguments against it."

The summary written by the biological anthropologist Vernon Reynolds was, perhaps, even more disappointing for some AAT supporters. Although he was quite taken by the diving reflex evidence and seemed to conclude that human ancestry must have therefore been close to fresh water - he was quite clear in coming down in favour of the savannah theory for the origin of bipedality, sweating-nakedness and sub-cutaneous fat.

However his concluding remarks were actually quite positive: "But at the same time there does seem to be evidence that not only did they take to water from time to time but that the water and by this I mean inland lakes and rivers) was a habitat that provided enough extra food to count as an agency for selection. As a result, we humans today have the ability to learn to swim without too much difficulty, to dive, and to enjoy occasional recourse to the water."



So was that it? Does this mean that the AAH has been officially dismissed? Hardly.

For a start  the editors themselves, forced themselves to come to some kind of conclusion, would probably have erred on the side of caution. They did say that " it may well be rewarding to reconsider the issue once further evidence - for instance, from paleontology - becomes available " and since 1987 there have been several significant discoveries, not least Orrorin tugenensis which should (but has not yet) set the cat among the pigeons about human evolution.

Some very significant studies (in particular about the affect of shaving on swimming times) had not been published at the time of this conference. And also evidence of gorillas, bonobos and chimpanzees wading has only emerged in the last few years.

Secondly, if you examine those papers against the theory there do seem to be several threads of misunderstanding and misrepresentation that can easily be answered.

Here is a review of some of the papers that had such a big influence on the way the AAH is perceived today in academia.

I've concentrated on those papers that argue against the AAH so that people can judge for themselves the strength of the AAH.

Who Participated?
There were 22 participants representing a wide range of opinions about the AAH. They were fairly grouped on both sides of the divide and included such leading aquatic lights as Elaine Morgan, Marc Verhaegen and such well known opponents as Peter Wheeler and Martin Pickford. The editors, headed by Lesley Vernon were chosen to be a little more neutral on the subject.

Full list of participants.


Part 1 - The Aquatic Ape Theory

1: The Origins of a Theory - Elaine Morgan (for, full text)


2: Why a New Theory is Needed - E. Morgan (for)


3: The Evolution of Genus Homo: Where it Happened - Leon P. LaLumiere (for)


4: Is an AA viable in terms of marine ecology and primate behaviour? - Derek Ellis (for)


5: Aquatic Features in Fossil Hominin s? - M Verhaegen (for)


Part II - Reactions to the AAT For and Against

6: The Refutation that Never Was: The reception of the AAT. Graham Richards (for , abstract only)


7: Does the Geological Evidence Support the AAT? (127-132) - Martin Pickford (against, s ummarised Notes)


8: Adaptation and the AT - Alan Turner (133-141) (against, summarised Notes)


9: AAT seen from Epistemological and Paleoanthropological viewpoints - (pp142- 173) H & S Preuschot (against, summarised notes)


10: What Constitutes an Aquatic Mammal? (174-181) - Paul Leyhausen ( against, summarised notes )


11: Human Regulation of Body Temperature and Water Balance - Marc Verhaegen (for)


12: Adipose Tissue in Human Evolution - Caroline Pond (193 - 220) (against, summarised notes) (PDF)

13: Body Hair Reduction and Tract Orientation in Man: Hydrodynamics or Thermoregulatory Aerodynamics? - Peter E. Wheeler
(PDF) (221- 236) (against, summarised notes)

14: Human Respiration Adaptations for Swimming and Diving - John M. Patrick (for)


15: The Significance of the Human Diving Reflex - E. Schagatay (for)


16: The Burden of Locomotion in Water: Co uld the Aquatic Ape Have Overcome It? - J. Ghesquire and Helen Bunkens (PDF) (255-262) (against, summarised notes)

17: The Non-Aquatic Ape: The Aquatic Ape Theory and the Evolution of Human Drowning and Swimming - Ja n Wind (263-282) (against, summarised notes)


18: Do Aquatic Mammals Provide Support for the AAT? - Machteld Roede (for)


19: More Thoughts on the AAT
(PDF) How the Aquatic Adaptations of Man Differ from those of the gorilla and the chimpanzee. Karl-Erich Fichtelius
Some cardiac topographic and morpho-physiological observations of the common seal. Cornelius J. van Nie and Machtelde Roede.
The Answer: The Aquatic Ape Theory and the Savannah Theory combined. Sarah B.M. Kraak.
The Second Crisis. Erika Schagatay.
Human Sexual Dimorphism: A Speculative Approach. Erika Schagatay

20: Aquatic Man -Machteld Roede (for)

Part III - General Conclusions

21: Cold & Watery? Hot & Dusty? Our Ancestral Environment and our ancestors themselves: overview. - Vernon Reynolds (Full text). (PDF)

22: Epilogue: Is there a future for the Aquatic Ape Theory? (Full text)

Algis Kuliukas (December 2014)