On my post the other day about a new PNAS paper, “Censorship and science: a new paper and analysis,” I received a comment below from reader “Stephen”, which was held up because it was his/her first. I decided to make the comment a post because it might be educational. Stephen argues that that one important example of scientific censorship is the “aquatic ape” hypothesis.
You’ve probably heard of this hypothesis, first broached in a Darwinian manner by British marine biologist Alister (now “Sir Alister”) Hardy, and made public as recently as 1960, when he wrote this in New Scientist.
“My thesis is that a branch of this primitive ape-stock was forced by competition from life in the trees to feed on the sea-shores and to hunt for food, shellfish, sea-urchins etc., in the shallow waters off the coast.”
Reader Stephen thinks this hypothesis was not only “undeniable when the data are analyzed objectively,” but has been “censored out of existence by the scientific community. Here’s his comment:
Not all scientific censorship can be understood through a left/right prism. In palaeoanthropology, for example, the idea that human ancestors may have gone through a period where underwater foraging was important, undeniable when the data are analysed objectively, has been censored out of existence by the scientific establishment. Peer review, which acts to reinforce established paradigms, is great for keeping unfounded ideas from taking up valuable scientific space, but for paradigm shifting breakthroughs it fails utterly.
The reason the hypothesis appealed to many people is that it superficially seemed to explain a number of features of humans that distinguish us from other apes to which we’re related. These features include our lack of body hair and the presence of subcutaneous fat (hair is useless in water and fat keeps us warm). As Scientific American wrote in 2016:
Hardy put forward all sorts of features which could be explained as “aquatic adaptations”: our swimming ability—and our enjoyment of it; loss of body hair, as well as an arrangement of body hair that he supposed may have reduced resistance in the water; curvy bodies; and the layer of fat under our skin. He even suggested that our ability to walk upright may have developed through wading, with the water helping to support body weight.
Note that this “aquatic phase” was supposed to have occurred during a specific time period when we lacked transitional fossils between our common ancestor with apes and creatures fully on the hominin side of the tree (my bolding). More from Sci Am:
For Hardy, this aquatic phase would have occupied the gap in the fossil record that then existed—between around 4m and 7m years ago. He sensibly concluded his paper saying that this was all only speculation—a “hypothesis to be discussed and tested against further lines of evidence”.
In the 50-odd years since the presentation of this hypothesis, it has enjoyed a certain fame—or perhaps notoriety. The writer Elaine Morgan championed it in her book The Aquatic Ape, and developed the hypothesis further, marshalling a seemingly impressive range of characteristics to support it, including breath control and diet. It seems such a tantalising and romantic idea—but a closer look at the evidence reveals it to be little more than that.
Other features supposedly suggesting that we went through an aquatic phase are “stretched hindlimbs, voluntary respiration, and dilute urine.” Those features were suggested by Belgian biologist M. J. Verhagen, who also posited that our evolution occurred this way (my bolding)
The Aquatic Ape Theory states that our ancestors once spent a significant part of their life in water. Presumably, early apes were plant and fruit eaters in tropical forests. Early hominids also ate aquatic food; at first mainly weeds and tubers, later sea shore animals, especially shellfish. With the Pleistocene cooling, our ancestors returned to land and became bipedal omnivores and scavengers and later hunters of coastal and riverside animals.
Unfortunately, despite reader Stephen’s assertion that the hypothesis is “undeniable,” it’s been denied by most human evolutionary biologists, to the point where Wikipedia says this:
While the hypothesis has some popularity with the lay public, it is generally ignored or classified as pseudoscience by anthropologists.
Anthropologists do not take the hypothesis seriously: John Langdon characterized it as an “umbrella hypothesis” (a hypothesis that tries to explain many separate traits of humans as a result of a single adaptive pressure) that was not consistent with the fossil record, and he said that its claim that it was simpler and therefore more likely to be true than traditional explanations of human evolution was not true. According to anthropologist John Hawkes, the AAH is not consistent with the fossil record. Traits that the hypothesis tries to explain evolved at vastly different times, and distributions of soft tissue the hypothesis alleges are unique to humans are common among other primates.
To see why the hypothesis is now seen as pseudoscience, you can read either the 2016 Sci. Am. article linked above or John Hawks’s website post from just last year, “Why anthropologists rejected the aquatic ape theory.”
As Hawks notes, the discovery of hominin fossils in Africa and development of molecular dating methods, all taking place after the hypothesis was first adumbrated, led to rejection of the hypothesis that major features of our body and social behavior evolved when we were largely immersed in water between 7 and 4 million years ago. But he adds that surely populations of hominins that lived along the coast did use aquatic resources such as fish and shellfish, and we have some evidence for that in the presence of fish bones associated with human remains dating back 1.95 million years and continuing up to Neandertals. These, of course, are found only in populations that lived near the sea. But problems with the aquatic ape hypotheses are in the second paragraph below:
Still, evidence for fish or shellfish consumption in Pleistocene sites is mostly localized to coastal or riverside locations. Many populations, both modern and ancient, have lived far from coastlines and relied upon terrestrial foods. The nutritional advantages of aquatic foods may be matched in some populations by edible insects and other invertebrates. Human populations and nonhuman primates that eat only terrestrial foods do not suffer from a deficiency of essential fatty acids. Fish and shellfish are clearly valuable to many human populations and some primates, and they are strong signs of our lineage’s increasing diet breadth during the Pleistocene.
In 1997 the anthropologist John Langdon reviewed the evidence with which aquatic ape adherents had supported their ideas. He observed that the traits proposed as aquatic adaptations in humans appear in the fossil record at radically different times. Hominins were obligate bipeds more than two million years before any had a projecting nose or descended larynx. Early bipeds evolved larger jaws and teeth, the opposite expected from high-energy aquatic foods, and large brains appeared in only one branch of Homo during the last part of its history. These features were not evidence of an aquatic stage; they appeared at different times and in different contexts.
Now the fact that different adaptations appeared at different times is not strong evidence against the aquatic ape hypothesis, as adaptations to live in a novel environment could arise at different times. But the times they appeared are not the times suggested by adherents to the Aquatic Ape Hypothesis. As for other features:
Yet the record does not preserve hard evidence of body fat, body hair, or sweat. To aquatic ape thinkers these soft-tissue traits were some of the most persuasive similarities between humans and certain water-living mammals.
Better data from other primates shows the flaws in this idea. For example, humans are extreme in our high fraction of eccrine compared to apocrine glands, but chimpanzees and gorillas also have a higher fraction of eccrine glands in comparison to other primates. Humans have sparse body hair but chimpanzees also have notably sparse body hair, and all great apes have lower body hair density than other primates. The body fat percentage of human hunting and gathering peoples is indeed higher than chimpanzees and most arboreal primates, but the human range of body fat is much closer to that seen in gorillas and orangutans. Humans are not a departure from other primates in these traits; we follow the same trends as our close relatives, some to a greater degree.
But Hawks does give the eating of fish and shellfish some credit for molding modern humans. It’s just that we have no evidence for an aquatic phase of human evolution:
But the science was not kind to the aquatic scenario sketched by Hardy and Morgan. The growing fossil and genetic data of the 1970s and 1980s showed that the aquatic idea was finely tailored around missing evidence. When this evidence started to appear, it showed that there was no long Miocene gap in the fossil record during which an aquatic ancestor might have been hidden from view. Hardy and Morgan had both adopted stereotypes of how humans differ from other apes, leading them to emphasize skin, fat, and hair patterns in ways that are not borne out by better datasets from living primates. The skeletal traits these writers suggested as adaptations to the water actually evolved at different times and in different lineages.
What remains of their ideas is the value of fish, shellfish, and aquatic plants to some ancient hominins and other primates. Tool use and extractive foraging techniques like digging enabled some hominin populations to broaden their resource use within both savanna and woodland settings. Marshes, swamps, and shorelines had some valuable foods that were open to clever hominins. Eating fish and shellfish in particular may have facilitated the habitation of coastal areas and islands by some members of our genus.
Scientific American gives more critiques:
All the suggested anatomical and physiological adaptations can be explained by other hypotheses, which fit much better with what we actually know about the ecology of ancient hominins. Hairlessness, for instance, is only a feature of fully aquatic mammals such as whales and dolphins. Semi-aquatic mammals such as otters and water voles are extremely furry. Sexual selection and adaptations to heat loss better explain our pattern of body hair. Sexual selection may also explain our body fat distribution, which differs between the sexes. Voluntary breath control is more likely to be related to speech than to diving.
The diet of many of our ancestors certainly included marine resources—where people lived on the shores of lakes or the sea. But this was a relatively late development in human evolution, and humans can also survive and thrive on food obtained entirely on land. Compared with other animals, we are not actually that good at swimming, and our skin leaks as well, letting in water so that our fingers become prune-like after a long bath.
What about walking on two legs? That’s something all apes do a bit of—while wading in water, certainly, but also while reaching for fruit, performing aggressive displays or simply moving around in trees. If we evolved from ancestors who already stood up in trees, we don’t need an extraordinary explanation for why we ended up standing on the ground rather than running around on all fours.
And this:
Since Hardy and Morgan’s hypothesis was advanced, many of the gaps in the human fossil record have been filled, with at least 13 new species found since 1987. We have also made great strides in reconstructing the environment in which our ancestors lived. And we know that species as far as part in time as Sahelanthropus tchadensis 7m years ago andHomo erectus 2m years ago all lived in forested or open woodland environments. While some of these woods included wetland, this was just part of the mosaic of habitats that our ancestors learned to survive in, and there is absolutely no trace of a hominin ancestor as aquatic as that described by Hardy and Morgan.
We also have evidence our ancestors had to survive periods of extremely dry climate with little or no aquatic resources. Coping with these highly variable, patchwork environments required behavioural flexibility and co-operation, and our large brains and ultra-social nature likely emerged as a result. This flexibility ultimately led to the invention of culture and technology.
I’m not an expert in human evolution, but the failure of an aquatic lifestyle to explain our large brains, our bipedalism and, importantly, the lack of evidence that hominins didn’t live in aquatic habitats during the time that important features of our body developed—all this counts against the Aquatic Ape Hypothesis. However, simply giving alternative scenarios for the lack of body hair of presence of subcutaneous fat based on a terrestrial existence is not in itself strong evidence, but simply a terrestrial “adaptive story”. The decisive evidence seems to me to be where we lived—almost entirely on land—as judged from fossil evidence, as well as the failure of the aquatic ape theory to explain notable features of our bodies: our bipedality and large brains. (These evolved mostly after the time when we were supposed to be living largely in water).
Contrary to reader Stephen, then, the aquatic ape hypothesis is NOT “undeniable,” nor is there evidence that human evolutionists are in some kind of cabal to suppress the “aquatic ape hypothesis” because it goes against the terrestrial “established paradigm.” As far as I can see, scientists did take the aquatic theory seriously, but rejected it based on the preponderance of evidence. The accusation that scientists are suppressing novel and counterintuitive evidence out of a group desire to avoid major paradigm changes in their field is one sign of pseudoscience. In fact, these same accusations have been offered as reasons why scientists reject creationism. But, as you should know (read Why Evolution is True), we don’t reject creationism because we’re sworn to defend Darwin; we reject it because the evidence doesn’t support it! If any cabal existed to reject evidence, it consisted of the creationists who rejected Darwin’s paradigm-changing theory published in 1859. But that cabal couldn’t hold together, for it was crushed by the weight of the evidence for evolution.
One might say (and I suppose this has been said before): at present the Aquatic Ape Hypothesis is dead in the water.
Is anyone else having trouble seeing the comments and/or commenting via WordPress reader, specifically for this site? It also keeps treating me as if I’m not subscribed, so I’m having to enter my name and email below this comment, even now.
FWIW, I didn’t have to fill in my details for my comment at 9 below (the system now remembers them), or indeed for this reply; and my comment appeared immediately. The edit function also makes a welcome reappearance.
I’ve been gone for a week or more, but just today I’ve had to fill in my name and email in order to comment. Usually when that happens I can go to WordPress and sign in there and that will fix things so that WEIT remembers me, but today that didn’t work. I was already signed in at WordPress when I checked, still have to sign in every time here.
One bright spot, the Edit function has shown up every time I’ve posted today, and I haven’t seen that thing in months, maybe years.
We’re working on fixing the technical stuff; please bear with us.
Not complaining Jerry, and thanks for maintaining the site.
It now works perfectly for me probably for the first time ever! Well in yonks.
Yes, WordPress does not allow me to comment. I moved to the official website and all functions operate, including edit, as per usual.
As we pointed out in the paper, rejection of ideas/claims on scientific grounds (e.g., not supported by the evidence; logical fallacies used to “justify” claims, etc.) is not censorship:
“Contemporary scientific censorship is typically the soft vari-ety, which can be difficult to distinguish from legitimate sci-entific rejection. Science advances through robust criticism and rejection of ideas that have been scrutinized and con-tradicted by evidence (49). Papers rejected for failing to meet conventional standards have not been censored.”
Or, as we put in this paper:
https://www.mdpi.com/2075-4698/10/4/82
Suppression Versus Rejection
In scholarship and science there is a difference between suppression and rejection. Suppression occurs when the fear of social sanctions prevents ideas from being explored or empirical findings from being presented in scientific or public forums. In science, rejection occurs when an idea has been explored and the evidence has been found wanting. The history of science is replete with rejected ideas, such as a geocentric solar system, young Earth, spontaneous generation of life, and the phlogiston theory of air. These ideas were thoroughly explored and rejected because the evidence available overwhelmingly disconfirmed them.
In contrast, suppression prevents an idea even from being explored.”
I’m a big fan of your work, Lee. Keep piratin’!
D.A.
NYC
Is it really true that humans are the only apes that can voluntarily hold their breath?
Have you tried getting an experiment that amounts to waterboarding chimpanzees past an Ethics committee, in the last few decades?
Or do you have another way to “incentivise” your test species to hold their breath?
I’m not even sure if it is true.
Being able to blow bubbles using a straw might be a suitable proxy, and I’m fairly sure I’ve seen pictures of chimps doing just that. How you could extend it to animals with less flexible lips … tricky. And it doesn’t test against holding breath on inhalation.
How many genera of apes (and monkeys) can retrieve food temptations from the floor of a swimming pool? That I recall being done (in other behavioural experiments) by macaques IIRC. No reason to think other genera can’t do it.
Seems simple. Try training them to blow bubbles when a light goes on.
Proboscis monkeys live near water and often swim and dive (as deep as 20 meters) for food. Long-tailed macaques are also known to swim and play in and under water.
I love the last line.
Silly puns don’t make truths.
https://www.bbc.co.uk/programmes/b07w4y98
It seems to me that it would be very difficult to find fossils of early hominids that lived on the ocean shore, given that the bones might have sank into marshes or been covered up by rising sea levels. So saying we don’t have any fossil evidence is a bit disingenuous.
But aquatic species have a better chance of being fossilized.
How so?
We have no shortage of fossil sites that were very close to the contemporary shore line. To name two off the top of my head, the Bloombos cave in south Africa (where the figured ochre blocks were found, but the cave has extensive deeper (older) deposits, and associated “middens” of marine shell debris. The other one that springs to mind is the Gibraltar caves – though most of their reported occupation was Neanderthal, so after the AAH’s period of interest.
Of course, most of the global distribution of such sites which were formed since the start of the ice age are presently underwater, due to the draw-down of ocean levels in periods of high land ice cover, and their current rebound to interglacial levels. See, for example, all the press excitement over “Doggerland” in the (present day) southern North Sea.
The chance of any organism getting fossilised is very low anyway, and where it lives has a massive effect on its chances of it getting fossilised (technically the study of this is called taphonomy). If an animal gets buried in a swamp it probably has a better chance than most. If the swamp dries out and gets buried in later deposits it could turn to stone with the animal’s fossil still there. On a shore with active waves and rolling pebbles there wouldn’t be much chance at all. I sometimes wonder about birds, or maybe pterosaurs that might have nested on cliff faces, and its hard to think of any circumstance where such animals might become fossilised. There could have been many such creatures that we could never know about from the fossil record.
Just to add:
Reading this made me wonder about sea otters, so I Googled it:
“The sea otter presents an insight into the evolutionary process of the mammalian invasion of the aquatic environment, which has occurred numerous times over the course of mammalian evolution. Having only returned to the sea about 3 million years ago, sea otters represent a snapshot at the earliest point of the transition from fur to blubber.”
… so they haven’t had time to make the transition.
Sea lions and such don’t seem to find fur useless either. And sea birds keep their feathers. Apparently neither hair nor feathers are hinderances to an aquatic lifestyle. They are both helpful in fact.
There are several once fashionable ideas about our evolution that have been set aside, or at least demoted. Besides the AHH, there was the hypothesis that we evolved upright walking on open Savanahs (that being at least demoted, since fossils of early bipeds are associated with forest ecologies). Then there was the idea that we co-evolved extra large brains with bipedal walking, so to free up our hands to use tools. That view inspired the iconic image of our progressive evolution toward more fully erect modern man, in parallel with more and more advanced tools in hand. But the fossil record shows that those evolved at different times.
Some hypotheses are more likely wrong than right, and the science caravan can move on.
Yep. Given some of the more current data regarding tool use among our more recent ancestors and genetic studies regarding human brain evolution, in particular a group of studies about a frame shift caused by a single point mutation that seems to be responsible for a very significant increase in the size of the human cortex, it seems likely that our ancestors had already become quite smart, and then later we became even smarter.
Or one might say that the evidence leaves the Aquatic Ape Hypothesis high and dry.
As a hypothesis it has definitely sprung a leak…
Indeed.
To be harsh but perhaps reasonably fair, a hypothesis “finely tailored around missing evidence” is weak and is tantamount to a conspiracy theory. Robust, strong theories becomes more likely as evidence accrues and they are tested. The happenstance conspiracy – conspiracies exist – would behave similarly despite their weak foundations.
We don’t see that here.
Despite being nailed to the missing evidence, this hypothesis has kicked the water bucket.
Thank you for another educational and well-argued science article. This is one of the many things that make WEIT such a compelling site.
I remember reading Elaine Morgan’s book when it came out and concluding that it was ridiculous. It seemed to me to be more a rejoinder to Desmond Morris’s The Naked Ape than a serious theory. I was 15 at the time I read it, so I was not politically aware and I didn’t reject it because of any opposition to feminism. To me, the claim of an aquatic phase in human evolution simply did not make sense. (IIRC, Elaine Morgan seemed to argue that women were aquatic but men were not, which was doubly ridiculous to me at the time.) We already were quite aware, thanks to the work of the Leakey’s, that the focus of human evolution was terrestrial East Africa.
In reading the above, I’m actually quite surprised that the theory got the amount of attention that it did. Sometimes a theory is rejected simply because it is implausible, not because of censorship.
It returns like the proverbial “bad penny”, on a regular basis. Refuting it takes an undue amount of time, because it is superficially appealing and most of the people who get attached to it are amenable to examining contradictory evidence. In that respect, “aquatic ape”-ers are a more valuable, and far more time-consuming, target than dyed-in-the-wool Creationists.
Morgan’s second book was much better: variables replaced attributes. Thus “A had x” and “B had y” were superseded by “A tends towards x more than B does”, etc.
Enjoyed reading this, even though I wasn’t aware of the “aquatic ape” hypothesis. Good example of how scientists apply evidence to hypotheses.
It’s sort of surprising to me to come across someone still so devoted to the AAH.
I was once interviewed for an AAH-related study: Tuomisto et al. (2018), How scientists perceive the evolutionary origin of human traits: Results of a survey study. Ecology & Evolution, doi.org/10.1002/ece3.3887. The results of this study: Most scientists in relevant fields (ecology, evolution, anthropology) tend to disagree with the AAH, but the ones with the most relevant expertise (paleoanthropologists) disagree with it much more strongly than other scientists. One possible conclusion: nonexperts are the main ones promoting the continued existence of the AAH. Everyone wants to have an opinion on human evolution!
Thanks for an excellent exposition of how the scientific method works in dispelling a hypothesis that seems attractive but is nonetheless unsupportable.
One small bit pricked my attention and I didn’t see it discussed further: that humans’ ability to make dilute urine implies an earlier aquatic existence. This doesn’t stand up. Animals adapted to full time ocean life where they have no access to fresh water must still be able, like all membrane-bound life forms, to maintain their body fluids within very tight limits in a state, for all mammals, about one-third as salty as sea water. (This is the most robustly defended variable in human physiology. Ten per cent excursion up or down, if rapid, causes life-threatening health problems.) There are a number of strategies for accomplishing this but none of them involve dilute urine. Making urine that is saltier than body fluids, rather, is one approach.
Animals that spend much of their time wading or swimming in fresh water don’t need to worry about this. They can drink the water according to thirst. They only time they need to be able to excrete urine that is more dilute than body fluids is if, for some reason, they have drunk more water than they need. Humans can indeed excrete highly dilute urine about one-sixth the tonicity of plasma. This is a good thing given our frequent consumption of large quantities of salt-poor fluids for social purposes far beyond what we need to slake thirst. This likely enabled pissing contests as a competitive mating ritual.
But this ability to produce dilute urine ought to tell us nothing about how much time our ancestors spent wading around in rivers, and it undermines the theory that we were ever pelagic, where it would be counter-adaptive.
(For brevity I’ve elided over the kidney’s ability to regulate electrolyte balance and water balance independently of each other, trading off the needs for both, and still do its other life-essential job of excreting the wastes of protein catabolism.)
I remember Elaine Morgan’s 1972 bestseller, The Descent of Woman, which spun a version of the Aquatic Ape hypothesis. If I recall correctly, her thesis was not that all humans but only women “evolved in the water.” Full frontal intercourse was one of the successful adaptations. The book sold in the millions and was translated into 10 languages.
Being hairy doesn’t negate hydro habitation: otters, beavers, muskrats, etc. What a dumb idea that humans needed to lose hair to succeed in water. If prehistoric humans were hunting for shellfish underwater, spearing fish, etc., having a hairy body wouldn’t have been an impediment. It’s not like wearing clothes…human hair is negligible, even a very hirsute specimen works well in water, thank you very much. Probably not good if you’re trying to win a gold metal in swimming category (milliseconds!), but for the efforts of hunting/scavenging/foraging in water, I can’t see natural selection selecting baldness in any of its myriad manifestations when it comes to “helping” the bald ape swim for fitness or survival.
Perhaps baldness was sexy. The chicks dug it…is there a paper on that one? Are humans immune to sexual selection? I think not…why would we be? This assumes XX lost hair first though, right? Biology is too difficult…
We are not the aquatic ape, we are the sweaty ape. Standing upright minimized our profile to the sun except for the head and therefore the brain. We have extra blood going to the brain to keep it cool. None of this is necessary in an aquatic environment. The water keeps you cool. Duhh!!
Some brains! Not mine 🤪
Not so much umbrella hypothesis, but theoretical overreach? I read Elaine Morgan’s book “Scars of Evolution” – must have been – more than twenty years ago. Great to have the latest update on the AAH, so thanks Jerry.
The most satisfying explanation I have heard for modern humans’ relative hairlessness, is the idea that ancestral humans were persistence hunters. As I understand, it some modern people, such as the !kung still use this method. The idea here is that to hunt a relatively large animal, you get as close as you can and throw a spear at it. Light throwing spears are unlikely to finish the animal off, which means that to complete the kill the hunters then have to track and follow their wounded prey keeping it moving, for days if necessary, until it succumbs to blood loss and/or heat stress, at which point it can be finished off. The point is that humans can carry water with them while non-human animals can’t, so humans can afford to lose water by sweating to keep cool. The prevailing hypothesis as I understand it is that because hair diminishes skin’s capacity to lose heat by evaporation, selection favoured hairlessness.
We know that Neanderthals didn’t use light throwing spears, but heavy thrusting ones, and it seems likely that persistence hunting wouldn’t have been nearly as effective in the cooler climes of Northern Europe and Asia as it would in the hot African savannah where anatomically modern humans (AMH) are thought to have evolved, suggesting that Neanderthals would have needed, and used, a different hunting strategy. Some scientists have suggested that they might have been ambush predators. My thought, here, would be that they might also have been expert trappers, using snares, deadfalls or even nets for example: unlike their stone technology, fossil evidence for the remains of organic technology like this would be unlikely to survive.
I’m hesitant to make this next point because there is a ridiculous assumed association between human/hairlessness, and animal/hirsuteness. (To follow this absurd assumption would suggest that elephants, rhinos, hippos and pigs are more “human” than more follically privileged non-human mammals.) But it is a view that many people who are less scientifically literate might have, and is probably, unfortunately, well established. It doesn’t seem likely to me that the hypothesis I’m about to put forward in the next paragraph hasn’t occurred to palaeoanthropologists, but they might be unwilling to put it in the literature for this very reason.
You know where this is going don’t you? We don’t know the extent of Neanderthal’ hair coverage, but it seems likely that the selective pressure for hair loss during their evolution would have not been as strong in Neanderthals as it was in AMH, and unless Neanderthal’s clothing technology was also more advanced than we understand it to have been, it is possible that Neanderthals, and possibly Denisovans, might have had fully furred, or even densely furred bodies. Other primates that live in cooler climates like the Japanese macaque have much thicker fur than those that live in cooler conditions.
But there again, maybe I’m guilty of my own theoretical overreach. 😊
Great post.
I don’t think human ancestors lived near the Indian Ocean – well, possible sites might be under water, depending on their age, but early modern Homo must surely have had sea-going canoes to reach some locations, but that is a completely different aquatic hypothesis!
Just reading a newly published book Human Origins by Sarah Wild. Recommended inteoduction.