Aquatic Ape Human Ancestor Theory

Aquatic Ape Theory - What is it?

A Brief Summary of AAT - key arguments

A Brief History and Key Proponents of AAT

Current Aquatic Evolution Theories


Alternative theories of human evolution

Wikipedia and the scientific community

. Anatomical Evidence
... Bipedalism
... Birth and babies
... Brain
... Breath control
... Fat
... Fingers, toes and feet
... Furlessness
... Hair and baldness
... Kidneys
... Menopause
... Nose
... Olfactory sense
... Pachyostosis
... Paranasal Sinuses
... Platycephaly
... Sexual features
... Surfer's ear
... Sweating
... Tears
... Underwater vision

. Diet
. Language & Song
. Sleep (USWS)
. Waterside environments
. Sea Gypsies

. Homo erectus - shallow diver

. Fossil evidence
. Paleoecological evidence

A call to scientists...

Recent News and Updates

Books and publications

Videos links



Homo erectus - shallow diver

Sir Alister Hardy asked the question: "Was Man More Aquatic in the Past?" and the answer must surely be: yes. Homo sapiens generally survives today as a terrestrial species, with a strong affinity to water, residing predominantly near water, and with a large part of our diet still consisting of seafood. However, with the exception of a few distinct ethnic groups, human beings can no longer claim to be a semi-aquatic species.

But if we were more aquatic in the past, when was it and which species can claim that distinction? Of all the Homo ancestors, one stands out as being the most 'different' from the great apes, and has the most 'aquatic' features of all, including Homo sapiens.

"When the Dutch physician Eugène Dubois unearthed in eastern Java in the early 1890s the skull cap and the femur of what he first named Anthropopithecus and later Pithecanthropus erectus (now the type specimen for Homo erectus), he was struck by the extraordinarily massive cortical bone tissue, and he interpreted this as a sign of the primitiveness of these bones. Later researchers, such as Franz Weidenreich, thought the heavy bones suggested that H. erectus individuals were giant creatures. As more fossils were discovered, however, it became clear that, although not small, these individuals were no giants, but instead had relatively very compact and thick bones [2, 3], beyond the range of optimal strength/weight ratio. Different hypotheses have been put forward to explain this curious feature, but so far there has been no consensus." [1]

The truth is that the increased density of the H.erectus skeleton would have left them wholly unsuited to running, or even prolonged terrestriality, as heavy skeletons are energetically expensive to move and their heavy, hyper-mineralized bones would have more easily fractured, a risk that rises with velocity. In other words, Homo erectus would probably have broken his legs if he had tried running across the savannah after prey. We can therefore assume that H.erectus likely made few sustained terrestrial forays. The summed evidence of bone gross morphology and micro-structure indicates that H.erectus were fully committed to an aquatic lifestyle, and bore marked adaptations for bottom-walking, paddling & undulatory swimming modes. [4]


[1] Stephen Munro and Marc Verhaegen, Pachyosteosclerosis in Archaic Homo, Chapter 5. Was Man More Aquatic in the Past? Fifty Years after Alister Hardy, Waterside Hypotheses of Human Evolution, Bantham science publishers, 2011. p. 82
[2] Boaz T, Ciochon RL. Headstrong hominids. Nat Hist 2004; 113: 28-32.
[3] Boaz T, Ciochon RL. Dragon Bone Hill: An Ice-Age saga of Homo erectus. Oxford: Oxford University Press 2004.
[4] The postcranial skeleton of H.erectus after SI Madar 2007 J Paleontol 81:176


Homo erectusNot only does a waterside lifestyle fit well with the known nutritional needs of Homo sapiens, it can help explain many otherwise unexpected features of human anatomy, behavior and physiology.

Bramble and Lieberman [2] suggest that a shortened femoral neck could have been an adaptation to more efficient running, yet this feature first appears in Homo sapiens and is absent from earlier Homo species such as erectus. This implies that Homo erectus, with a relatively long and more horizontal femoral neck [3] was a less efficient runner than Homo sapiens. Other anatomical features point to the same conclusion, including the thicker, heavier cranial and post-cranial bones of Homo erectus and the less flexed cranial base [4]. With a generally thicker cortex and narrower medullar cavity, the limb bones of Homo erectus were dense and heavy compared to Homo sapiens and other primates, and the cranial bones were generally thicker as well [5-10]. The extra weight created would have been an unnecessary burden for an endurance runner [4]. Long-distance human runners are lightly built compared to sprinters, and cursorial mammals such as dogs and horses do not have thick, heavy bones.

The basicranium of Homo erectus is relatively flat compared to the very flexed condition seen in Homo sapiens [5, 11-13], and this is probably associated with a more elongated braincase and with a “peculiar poise of the head” [11]. The line of vision in Homo erectus, as a result of this peculiar poise, would have been somewhat more towards the sky than towards the horizon (or foreground) is the case in Homo sapiens. In a swimming/diving position, the less flexed basicranium of Homo erectus would mean the eyes were more naturally oriented in the direction the individual was moving (i.e., head first through the water). Although it remains to be seen how much time our ancestors may have once spent in the water, there is no doubt that the heavier bones of Homo erectus as well as the less flexed basicranium strongly contradict cursorialism [4].


[1] C. Leigh Broadhurst, Michael Crawford and Stephen Munro: Littoral Man and Waterside Woman: The Crucial Role of Marine and Lacustrine Foods and Environmental Resources in the Origin, Migration and Dominance of Homo sapiens; Chapter 2: Was Man More Aquatic in the Past? Fifty Years after Alister Hardy, Waterside Hypotheses of Human Evolution, Bantham science publishers, 2011. p. 23
[2] Bramble D, Lieberman D. Endurance running and the evolution of Homo. Nature 2004; 432: 345-52.
[3] Ruff C. Biomechanics of the hip and birth in early Homo. Am J Phys Anthropol 1995; 98: 527-74.
[4] Verhaegen M, Munro S, Vaneechoutte M, Bender-Oser N, Bender R. The original econiche of the genus Homo: Open plain or waterside? In: Muñoz S, Ed. Ecology research progress. New York: Nova Publishers 2008; pp.155-86.
[5] Klein RG. The human career. Chicago: University of Chicago Press 1999.
[6] Jacob T. Solo Man and Peking Man. In: Sigmon B, Cybulski J, Eds. Homo erectus: Papers in honor of Davidson Black. Toronto: University of Toronto Press 1981; pp. 87-104.
[7] Mania D, Vlcek E. Homo erectus in middle Europe: The discovery from Bilzingsleben. In: Sigmon B, Cybulski J, Eds. Papers in honor of Davidson Black. Toronto: University of Toronto Press 1981; pp. 133-51.
[8] Kennedy GE. Bone thickness in Homo erectus. J Hum Evol 1985;14: 699-708.
[9] Rightmire G. The human cranium from Bodo, Ethiopia: Evidence for speciation in the middle Pleistocene? J Hum Evol 1996; 31: 21-39.
[10] Wood B. The history of the genus Homo. Hum Evol 2000; 15: 39-49.
[11] Maier W, Nkini A. The phylogenetic position of Olduvai Hominid 9, especially as determined from basicranial evidence. In: Delson E, Ed. Ancestors: The hard evidence. New York: Alan R. Liss 1985; pp. 249-54.
[12] May R, Sheffer D. Growth changes in internal and craniofacial flexion measurements. Am J Phys Anthropol 1999; 110: 47-56.
[13] Lieberman D, McBratney B, Krovitz G. The evolution and development of cranial form in Homo sapiens. Proc Natl Acad Sci USA 2002; 99: 1134-9.

Homo erectus - Long distance runner?

"Most other people, including most AAT proponents as far as I can see, accept the conventional wisdom‚ that Homo erectus was a long distance runner on open savannas.This is pure nonsense: distance runners are lightly built (Arab horse, greyhound...), but erectus' skulls were twice as thick as those of gorillas, they were also more dense, with narrower marrow.Such heavy bones are very brittle (in other mammals & in human pathology). The only species with such heavy bones are slow littoral waders (heavy leg bones) &/or divers (heavy skulls).

H.erectus can't have run (or even gone) over savannas to Flores: they had to swim. This was no problem: all typically erectus features suggest frequent diving.

Whatever conventional "wisdom" tells us, long distance running is at best a very recent adaptation of some adult males a few isolated inland populations (E.Africa, Australia), with "modern" technology such as water containers etc." Marc Verhaegen

A New Look for Early Homo

Scientists uncovered a stunning skull that gives a fresh portrait of early humans. For more on the most complete early Homo skull ever found, read the news story and research article.

Website: F. Mansfield, 2015

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