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

When / Where / How?

Ape to Human Evolution Timeline

Alternative theories of human evolution

Wikipedia and the scientific community

... Anatomical Evidence
... Bipedalism
... Birth and babies
... Brain
... Breath control
... Descended larynx
... Diet
... Diseases
... Fat
... Fingers, toes and feet
... Furlessness
... Hair and baldness
... Human ailments
... Kidneys
... Language & Song
... Menopause
... Nose
... Olfactory sense
... Pachyostosis
... Paranasal Sinuses
... Platycephaly
... Reverse osmosis
... Sexual features
... Sleep (USWS)
... Surfer's ear
... Sweating
... Tears
... Underwater vision
... Viruses
... Waterside environments

. Homo Ancestors
... Trachillos bipedal hominids
... Homo erectus
... Homo neanderthalensis
... Sea Gypsies/ the Moken
... Homo sapiens - water afinity
... Coastal Migration
... Pan and Gorilla ancestry
... Semi-Aquatic Animals

. Testable Hypotheses
. Fossil evidence
. Genetic evidence
. Paleoecological evidence
. Retroviral marker in apes
. Acheulean handaxes

A call to scientists...

Recent News and Updates

Books and publications


Videos links



Homo neanderthalensis (Neanderthals)

There can be no doubt that Neanderthals lived a semi-aquatic existence. We know this from the abundance of shell middens and aquatic fossils found wherever there are Neanderthal remains [1]. Also, they have specific adaptations to cold water living: compared to modern humans, Neanderthals were stockier, with somewhat shorter limbs and a larger chest. These features are often explained as adaptations to conserve heat in a cold climate, but may also be adaptations for swimming in cold waters. They had other had cold-specific adaptations, such as specialised body fat storage and an enlarged nose to warm air (though the nose). That European neandertals were waterside omnivores is biologically obvious, e.g. -anatomy: pachyosteosclerosis (POS), platycephaly, ear exostoses, projecting mid-face, large brain (DHA), large lungs... -isotopes intermediate between littoral & freshwater foods, -fossilization in river valleys, sea-coasts, oxbow lakes, beaver ponds...

Archaic homo fishing

Intelligence: The braincases of Neanderthal men and women averaged about 1,600 cm3 (98 cu in) and 1,300 cm3 (79 cu in) respectively, with the largest recorded cranium estimated at 1740 cm3, [2] which is even larger than the values for modern humans (1260 cm3 for men and 1130 cm3 for women). This indicates a diet rich in seafood.

Homo sapiens and neanderthal skulls

Were Neanderthals fat?: Unfortunately fossils do not reveal how much fat a species carried but recent genetic research indicates that Neanderthals had a gene (which we may have inherited from them) that makes us store more subcutaneous fat. [3]

[picture credit]

Ear exostoses: [4] [5] [6]

"New evidence that Neanderthals got surfer’s ear suggests our extinct relatives spent a lot of time in the water. They probably weren’t catching sick waves, but instead they were perhaps hunting fish, mollusks or other marine resources, a new study in the journal PLOS One shows.

Surfer’s ear is different from the more common swimmer’s ear, which is a bacterial infection in the outer ear canal. In exostosis, the ear canal begins to grow bony protrusions in response to repeated exposure to cold, moist conditions. It’s the body’s way of protecting the eardrum, but the growths can lead to hearing loss, wax impaction and increased infection.

Issam Ahmed at AFP reports that as far back as 1911, paleontologists noticed exostosis growths on a Neanderthal skull, but until this most recent study, no one had looked deeper into the matter. That’s why a team led by paleoanthropologist Erik Trinkaus at Washington University in St. Louis examined 77 remains of early Homo sapiens and Neanderthals uncovered in Europe and West Asia.

They found that surfer’s ear existed in about a quarter of the human skulls, similar to the rate the disease occurs in humans today. But nearly half of the Neanderthals examined had the mild to severe cases of the condition, suggesting that the ocean played a big role in their lives. And if they were fishing, it means they may have been more advanced than some researchers believe.

“It reinforces a number of arguments and sources of data to argue for a level of adaptability and flexibility and capability among the Neanderthals, which has been denied them by some people in the field,” Trinkaus tells AFP’s Ahmed. “You have to be able to have a certain minimal level of technology, you need to be able to know when the fish are going to be coming up the rivers or going along the coast—it's a fairly elaborate process.”

This isn’t the only paper to suggest the ear problem is a sign Neanderthals liked seafood. A 2017 paper, noting the prevalence of the condition in Neanderthals and early humans, suggests that it was an evolutionary adaptation to early hominins diving into cold lakes, rivers and seas to collect food."

Fossilised neanderthal ear exostoses

Culture and rituals: Neanderthals probably buried their dead. [6]

Large eyes: useful for deep water swimming [7]

Neanderthals collected clam shells from the bottom of the sea to make tools [8]

Neanderthal shell tools

Neanderthals were hooked on fishing for their food. [9]

Neanderthal beachcombers went diving for seashells, scientists discover [10]

Papers and discussions

Neanderthal foraging in freshwater ecosystems: A reappraisal of the Middle Paleolithic archaeological fish record from continental Western Europe

Emilie Guillauda, Philippe Béarez, Camille Daujeard, Alban R. Defleur, Emmanuel Desclaux, Eufrasia Roselló-Izquierdo, Arturo Morales-Muñiz, Marie-Hélène Moncel


The prevalence of large game found in association with Middle Paleolithic tools has traditionally biased our ideas of Neanderthal subsistence practices. Studies document the exploitation of small mammals, birds, and plants by Neanderthals, whereas data on aquatic resources are still scarce and data on fish are almost non-existent. This article presents a review of fish remains from 11 Middle Palaeolithic fish bone assemblages from well contextualized sites in Belgium, France and Spain. It explores the nature of the evidence in order to determine whether Neanderthal fished and if so, whether fishing was a casual, opportunistic activity or a systematic practice. The first issue to address is whether archaeological fish remains at any given site represent human activity or not. Our study tests that assertion while enhancing our understanding of the diversity of food alternatives available to Neanderthals at any given site, and their ability to adapt to them. Methodological protocols include quantification, body mass and length estimations, and, whenever possible, spatial distribution of fish remains, taphonomic analyses and inference of the season of death. This methodology constitutes an analytical protocol to assess the contribution of fish to the human diet during the Paleolithic and set apart human-generated fish deposits from those generated by alternative fish accumulators. The evidence gathered so far points essentially to circumstantial fishing by Neanderthals, and the question must necessarily remain open for the moment. Nevertheless, some of the evidence, in particular the presence of large (>1 kg) fish in anthropogenic deposits and the absence of animal digestive traces and gnawing marks on fish bones in such deposits, seems compelling and suggests that Neanderthals could have played a role in the accumulation of some of these remains.

Quaternary Science Reviews, Available online 14 December 2020, 106731

Portugal: Intertidal Archaeology and Submerged Coastal Landscapes

Nuno F Bicho, Leandro Infantini & Joao Marreiros 2020 in "The Archaeology of Europe's Drowned Landscapes"[0]=CRdlHNTPiAKkxbClZMdmDoi1HuW5ZGL_ENhosK-4mlgr9SaHpx0Clmthu2fOHK5xCubof1kR3v4XbGaturYwtpkjPw._8lyGBZ9SrMP7sLa17LfLwMX1ZRodeS5Tv7_lDx7uvl6JfL34rgwslefpXHI-a8-oWl7F5cj6T5FpZGUU4xgUg

People have lived along the Portuguese coast at least since MIS-5  >100 ka. There are many known sites & archaeological evidence of human settlement on land, but there are only a handful of known submerged or near-submerged locations, and these are all in the present-day intertidal zone. Throughout the period, diet was based on terrestrial & marine mammals, fish & shellfish. This dietary regime was already in existence when Hn populated the region.

It appears that marine foods started to be used more frequently when the first Hs arrived, some 33 ka. Among the Mesolithic people who lived along the estuaries of the major rivers, marine food frequently composed c 50 % of the diet. With the introduction of agriculture, coastal resources became less important, although some submerged sites of Neolithic date testify to habitation directly at the sea-shore.

Despite the current absence of known underwater prehistoric sites, apart from those in the intertidal zone, recent studies of offshore topography have identified a number of areas with good potential for archaeological prospection, including cliff lines with underwater caves & drowned river valleys.


If the H/P-LCA lived in coastal forests &/or lagoons 5-4 Ma (Red Sea or E.Afr.coasts? eg, Zambia mouth??), and after the split Homo populations
(why? innovation in shellfish opening??) spread along the coasts of the Indian Ocean (still aquarboreal?), this can explain the retroviral data
(Yohn cs 2005 PLoS). At the beginning of the Ice Ages, when sea levels dropped (1st drastic drop c 2.6 Ma?), Homo was preadapted to colonise the drying continental shelves, where they learned to dive for shellfish & to use stone technology to open them. This explains most of the differences between P& H: archaic Homo's huge brains, flat long heavy skulls, thick bones, external nose, intercontinental coastal dispersal, stone tool industry,
early sites of Mojokerto etc.

I'd think they often lived in kelp forests during the glacials, but during interglacials they waded more (more bipedal?) in estuaria etc.?
The sparks of the stone tool industry led to control over fire (already 1.5 Ma??) for opening shells, preparing foods, protection? This (or/& other technological innovations?) could have helped them to enter the land along the rivers (esp.interglacially?). This could explain the shift from salt
water (renculi & vernix caseosa in human newborns) to fresh water adaptations. Once a year, they still lived at the coasts ("holidays") collecting seafood, but most of the time they gathered shallow freshwater& waterside foods, diving & probably also wading (traces of cattails on neandertals tools).

The discovery of composite (distance) weapons (harpoons...) made wading more attractive than diving, which explains the the evolution of sapiens
from more archaic ancestors: longer legs, less heavy bones, higher skulls, basi-cranial flexion (directing the eyes more downward) etc. According to
isotopic data, sapiens (in Europe at least) fed also on fish & fowl (Richards cs 2001 PNAS). This preadapted to cooperation with wolves, eg, sapiens wading in reedbeds chasing ducks, wolves waiting at the waterside. Pups raised in floating huts (cf Marsh Arabs) became domesticated to dogs,
explaining why +-all dogs like to swim. The cooperation human+dog+weapons preadapted them to leave the water (safer from felids, canids & ursids)
and to evolve from wader to walker. Throughout this evolution, we probably ate more plant (incl.cane, papyrus, cattails, rice etc.) than animal foods I'd think.



HN Top Predator?

Reply to Fontes-Villalba et al.: On a reluctance to conjecture about animal food consumption
Sponheimer M, Alemseged Z, Cerling TE, Grine FE, Kimbel WH, Leakey MG,
Lee-Thorp JA, Kyalo Manthi F,Reed KE, Wood BA & Wynn JG 2013

Fontes-Villalba cs (1) correctly observe that C isotope ratios in tooth enamel do not speak directly to plant vs animal food ingestion. C isotope ratio data are useful for quantifying the consumption of C3-or C4-derived C, whether it comes directly from C3 or C4 plants, or indirectly through consumption of animals that eat those plants. Not only do we acknowledge as much in our recent series of papers, but we have made this point in print many times over the past 2 decades (ref. 2& references therein). However, to what extent can we speak to animal food consumption by early hominins?

To address this question, we first note that "early hominin diet" is a convenient abstraction at best, as the hominins discussed in our reports spanned a period of greater than 3 My, and evinced major differences in masticatory anatomy & associated archaeology. Given this heterogeneity, and the likely corollary of marked diversity in early hominin diets, it is not only plausible ― but probable ― that C4 food acquisition & consumption differed among hominin spp, eg, given Par.boisei's high δ13C values, robust mandibles, low-cusped cheek-teeth & diminutive incisors & canines, it is improbable that its major C4 dietary input was meat: even savanna carnivores may not attain such high δ13C values (3). It is, therefore, most parsimonious to ascribe the preponderance of its C4 "signal" to the direct consumption of C4 plant foods.

The situation for contemporaneous Homo might well be different. Its dental morphology, the general belief that it made & wielded stone tools, & arguments derived from energetics are consistent with Homo having consumed greater amounts of animal protein. Nevertheless, these lines of evidence tell us little about the abundance of animal products consumed, eg, although the archaeological record unquestionably informs us about the
technical capacities of early hominins, it cannot discriminate between diets that comprise 5 or 50 % animal foods. In addition, the "expensive
tissue hypothesis" cited by Fontes-Villalba cs (1) does not speak directly to animal food consumption, but rather to an increase in the consumption
of "high-quality" (nutritionally dense) foods by Homo. These foods include not only animal tissues, but also "nuts or underground tubers" (4).

We are reluctant to speculate about the fatty acid & micro-nutrient requirements of early hominins & their dietary implications. We simply note that most primates (incl.some Hs) flourish on diets that are dominated by plant foods: among extant catarrhines, it is only Hs with a technologically
sophisticated hunting armamentarium that have been documented to subsist (under certain conditions) on large amounts of animal flesh (5).
We agree with Fontes-Villalba cs (1) that it would be surprising if most early hominins did not consume animal foods to some extent, given our
knowledge of the diets of Pan spp & the observed behavior of other savanna primates (6). We caution, however, that it is not possible at present to meaningfully address the relative importance of faunivory for any Plio- or early-Pleistocene hominin species, incl.those attributed to Homo.
It is for this reason that we eschewed conjecture about animal food consumption in the 11 or so taxa discussed in our papers.


IOW, the belief that Homo ate a lot of meat rests only on
- Homo's dental morphology (bunodont = omnivorous cf swine)
- Homo's tool use (sea-otter: seafood, chimp: nuts)
- energetics arguments (seafood etc.)

IOW, Hn were no "top predators": their taurodonty, traces of cattails on tools & of waterlilies in dental plaque, rel.small canines, bunodont teeth, heavy weight etc suggest Hn mostly ate plant food.


'Homo' is the only primate whose tooth size decreases as its brain size increases.

Andalusian researchers (BioMed Research International) have discovered that the genus Homo are the only primates where, throughout their 2.5-My
history, the size of their teeth has decreased in tandem with the increase in their brain size. The key to this phenomenon, which scientists call "evolutionary paradox", could be in how Homo's diet has evolved.

Digestion starts first in the mouth and, so, teeth are essential in breaking food down into smaller pieces.Therefore, the normal scenario would be that, if the brain grows in size, and hence the body's metabolic needs, so should teeth.

However, in the case of Homo, this has not been the case:
Juan Manuel Jimenez Arenas: "This means that significant changes must have occurred in order to maintain this trend."

A change in diet, incorporating a higher amount of animal food, must have been one of the keys to this phenomenon. The quality leap in Homo's diet (a greater intake in animal proteins, fats& certain oligo-elements) is essential for a correct working & maintenance of the brain. A larger brain allows greater social & cultural development, which led to the achievement of important technological innovations.

The researchers evaluated the relationship between the size of post-canine teeth & the volume of the endocranium in a wide set of primates, incl. the main representatives of Homo fossils."Before we started the study, it was well known that, throughout the evolution of humans, tooth-size diminished, and brain-size increased. We have established that they are 2 opposing evolutionary trends that have been linked for 2.5 My, when our first ancestors within the Homo genus first appeared on the evolutionary stage."

The authors also relate these changes to the inactivation of gene MYH16, linked to temporalis musculature, which fell in size c 2.4 Ma. This would do away with an important barrier for encephalization (a hypertrophied temporalis prevents the development of the cranial dome). Likewise, they analyzed their relationship with the inactivation of gene SRGAP2, which helps towards the evolution of the neo-cortex, playing a principal role in human brain development.

I just sent this comment:

Thanks a lot, your study confirms my recent papers based on comparative data (see below) that most or all East-African australopiths were
herbivores in wetlands (feeding predom.on papyrus sedges etc.?), that the South-African australopiths were more omnivorous, and that early-Pleistocene Homo populations trekked intercontinentally along the coasts as far as Indonesia, Angola & England (coastal sites of Mojokerto,
Dungo V & Happisburgh resp.) & from the coasts inland along the rivers, feeding on waterside & shallow aquatic foods.

Seafood is rich in brain-specific nutrients (e.g. DHA, explaining Homo's brain expansion, see the work of Stephen Cunnane, Michael Crawford, José
Joordens etc.), it's typically soft & slippery, can be processed without much chewing (explaining MYH16 inactivation), but often requires stone
tools (explaining the beginning of human technology & fire use).

Some of our publications on this:
-with P-F Puech 2000 "Hominid lifestyle and diet reconsidered: paleo-environmental and comparative data" Hum Evol 15:175-186,
-with S Munro 2002 "The continental shelf hypothesis" Nutr Health 16:25-27,
-with Puech & Munro 2002 "Aquarboreal ancestors?" TREE Trends in Ecol& Evol 17:212-7, google "aquarboreal",
-with S Munro, M Vaneechoutte, R Bender & N Oser 2007 "The original econiche of the genus Homo: open plain or waterside?" :155-186 in SI Muñoz
ed 2007 "Ecology Research Progress" Nova NY, google "econiche Homo",
-with S Munro 2011 "Pachyosteosclerosis suggests archaic Homo frequently collected sessile littoral foods" HOMO J compar hum Biol 62:237-247, and
"Pachyosteosclerosis in archaic Homo" :82-105 in M Vaneechoutte cs eds
2011 "Was Man More Aquatic in the Past?" eBook Bentham Sci Publ,
-2013 "The aquatic ape evolves: common misconceptions and unproven assumptions about the so-called Aquatic Ape Hypothesis" Hum Evol
28:237-266, google "unproven assumptions Verhaegen",
-S Munro 2010 "Molluscs as ecological indicators in palaeo-anthropological contexts" PhD thesis Austr Nat Univ Canberra.

--marc verhaegen

On the Relationships of Postcanine Tooth Size with Dietary Quality and Brain Volume in Primates: Implications for Hominin Evolution

Juan Manuel Jiménez-Arenas, Juan Antonio Pérez-Claros, Juan Carlos Aledo &
Paul Palmqvist 2014 open access
BioMed Research International 2014 ID 406507, 11 pages

Brain volume & cheek-tooth size have traditionally been considered as 2 traits that show opposite evolutionary trends during the evolution of
Homo. As a result, differences in encephalization & molarization among hominins tend to be interpreted in paleo-biological grounds, because both traits were presumably linked to the dietary quality of extinct spp.

Here we show that there is an essential difference between the genus Homo& the living primate spp: Post-canine tooth size & brain volume are related to negative allometry in primates, and show an inverse relationship in Homo. However, when size effects are removed, the negative relationship between encephalization & molarization holds only for platyrrhines & the genus Homo. There is no general trend for the relationship between post-canine tooth size & dietary quality among the living primates. If size & phylogeny effects are both removed, this relationship vanishes
in many taxonomic groups. As a result, the suggestion that the presence of well-developed postcanine teeth in extinct hominins should be indicative of a poor-quality diet cannot be generalized to all extant & extinct primates.

Did Europeans Get Fat from Neanderthals?

Contemporary European Hs have 3 times more Hn variants in genes involved in lipid catabolism than Asians & Africans. Although Neanderthals are extinct, fragments of their genomes persist in modern humans. These shared regions are unevenly distributed across the genome and some regions are particularly enriched with Neanderthal variants.

An international team of researchers led by Philipp Khaitovich of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and the CAS-MPG Partner Institute for Computational Biology in Shanghai, China, show that DNA sequences shared between modern humans and Neanderthals are specifically enriched in genes involved in the metabolic breakdown of lipids.

This sharing of genes is seen mainly in contemporary humans of European descent and may have given a selective advantage to the individuals with the Neanderthal variants.

Did Europeans get fat from Neanderthals?
Skeleton of a neanderthal (left) and a modern human (right)
[Credit: © Ian Tattersall]

The researchers analyzed the distribution of Neanderthal variants in the genomes of eleven contemporary human populations of African, Asian and European descent.

They found that genes involved in the lipid synthesis contained a particularly high number of Neanderthal variants in contemporary humans of European origin, but not in Asians and Africans.

"These sequences show signs of recent positive selection," says Philipp Khaitovich of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and the CAS-MPG Partner Institute for Computational Biology in Shanghai, China. "This may indicate that they give modern humans carrying the Neanderthal genotype a selective advantage."

Analyzing the influence of Neanderthal variants on lipid processing in modern humans, the researchers further found recent evolutionary changes in lipid concentration and expression of metabolic enzymes in brains of humans of European origin.

"We don't know what these lipid concentration changes do to the brain, but the fact that Neanderthal variants might have changed our brain composition has interesting implications," says Philipp Khaitovich. Further work is needed, however, in order to fully assess the potential functional effects of these changes.

The study has been published in Nature Communications.

Neanderthal ancestry drives evolution of lipid catabolism in contemporary Europeans

Ekaterina Khrameeva cs 2014
Nature Communications 5:3584 doi 10.1038/ncomms4584 free access

Although Hn are extinct, fragments of their genomes persist in Hs. Here we show that while the genome-wide frequency of Hn-like sites is
+-constant across all contemporary out-of-Africa populations, genes involved in lipid catabolism contain more than 3-fold excess of such sites
in contemporary Hs of European descent.

Evolutionally, these genes show significant association with signatures of recent positive selection in the contemporary European, but not Asian or
African populations. Functionally, the excess of Hn-like sites in lipid catabolism genes can be linked with a greater divergence of lipid concentrations & enzyme expression levels within this pathway, seen in contemporary Europeans, but not in the other populations.

We conclude that sequence variants that evolved in Hn may have given a selective advantage to Hs that settled in the same geographical areas.

Findings indicate existence of Neanderthals on Greek island of Naxos

Archaeological findings at the Stélida site, on the Greek island of Naxos, indicate the existence of humans on the island as early as 260,000 years ago.

Stélida is an archaeological site at the northwest coast of Naxos, first documented by the French School in Greece in the 1980s. An excavation in the area, by the Canadian Institute in Greece in cooperation with Antiquities Ephorate of Cyclades has now yielded evidence that the island was inhabited by Neanderthals, changing prehistoric data on Cyclades as a whole.

In 2013 the Stélida Naxos Archaeological Project, a geo-archaeological survey of a chert source and associated early prehistoric stone tool workshops, started on the site aiming among other things to provide a clear dating of the site. So far human activity on the islands of Cyclades was believed to have started in the 5th millenium B.C.

Scientists will further study the artefacts from the site in detail aiming to clarify how the quarry in the area was intermittently exploited for a large period of time in prehistory, from the Lower Palaeolithic through the earlier Upper Palaeolithic and Mesolithic. The discovery of such early material is of great significance because researchers will be able to document the way the Cyclades were inhabited and the routes populations used for their migrations.

Website: F. Mansfield, 2015

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