Aquatic Humanoids, Part 2

But one thing I think we didn't discuss last time, or if we did, it's my memory is not serving me well. Is the movie Leviathans. Oh. Yes, one of the one of the several nineteen eighty nine underwater Peril movies that that we keep chatting about, and at least in a previous episode. I'm not sure if we we talked about it in The Aquatic Humanoids Part one or not. We've talked about it so much recently I can't even

recall when it happened. But anyway, Yeah, so nine you had James Cameron's The Abyss, but you also had Deep Star six Leviathan, Lords of the deep for some reason, everybody went nuts making underwater sci fi movies. Yeah, we've been, so I'm just trying to piece together in a casual way why that was, you know what what was happening

in the world. Was it I did have to do with the with recent underwater exploration that really inspired everybody at the same time, or did everyone just know that the abyss was coming and it made sense for all the various cinematic lamp preyests to converge upon it. Now, Leviathan is a I think you'll back me up here, a terrible movie, but a great terrible movie. It is. Ah,

it is a thoroughly enjoyable, flawed film. It's the that's the type of bad movie that I just really eat up that ends up in I think inspiring me more than good underwater movies. Yeah, it's such an alien rip off. The DVD I had of it it actually said, is

alien underwater? That's the whole quote. Yeah, it is highly derivative, but it god that the cast is so good and the look of the film like it has a Stan Winston Studios monster in it, so you know that's gonna look like a million bucks, and the the the overall sets that are used, especially the interior sets for this underwater station, are tremendous. Like the set does as much as the cast does, really to create a sense of

backstory for these characters. You know, in a way, the sleaziness of Daniel Stearns performance in the movie is kind of a set in its own. It's like a landscape of sleez and obnoxiousness. Yeah, he plays this sleazy character named six Pack, I believe, and it's easy to think back on the film and think that their moments where the character reaches peak sleaziness, but he really just achieves

a high plateau of sleaziness throughout his time in the film. Okay, let's not dwell on Leviathan too much, but it does relate to what we're gonna talk about today. So today we wanted to address some of the biological ideas about aquatic humanoids. And so one of the things in Leviathan is you spoiler alert for this nineteen eighty nine B movie. You find out that the Russians in the movie, you're trying to create an aquatic humanoid through genetic alteration. Right,

of course that ends up creating a monster. A monster I should add that is in many ways kind of an ichno centaur, which we discussed in the first episode, this sort of hybrid of different parts creating this this kind of large centaur esque chimera. So, yeah, you've got this giant monster that's basically got a catfish head and then it's got Daniel Stearn's face sticking out of its back and some other random tentacles and Lamprey's poking off

of it. But this was, in the context of the film, an attempt to create Homo aquaticus, the human version of an underwater creature, or maybe the underwater version of the human today. We want to look at could such a creature exist and what would it look like biologically? And if the quatic humanoids could exist in reality, how would they figure into our our picture of human evolution. Yeah, it's it's a fascinating question, of course that you know.

The the easy answer is, of course, yes, all life came from the sea, and we have plenty of cases of terrestrial life returning to the sea. So we're not talking about just complete whackadoodle ideas about about life emerging from one or descending into the other. Right, you are correct to point out that that leaving the water for terrestrial existence can happen, and then leaving terrestria is that the now, and I guess leaving the land for a

watery existence can also happen. These are totally biologically plausible scenarios and they happen all the time. But could it happen with us? And in fact, has it already happened with us? So I guess it's time to venture into something that people have asked us to discuss on the show before. We we've never done it before, but it is a fringe hypothesis and human evolution called the aquatic ape hypothesis. Yes, and and of course that instantly summons

the images of a guerrilla mermaid. I will not, I will not try to convince you to dismiss that that apparition from your mind. But but it is almost impossible not to think of that. So now you're saying, like fish tail with guerrilla top, not like not like mermaid top with guerrilla legs. No no, no fish fish on the bottom, uh, silverback grilla on the top. That's the only way to put it together, Marilla. Yeah, not exactly, but close. Now, before we get into the specifics, of

the hypothesis. I just want to start by cautioning that this is not a hypothesis that is widely accepted by scientists or biologists. It's generally frowned upon by paleo anthropologists and other people who study the history of human evolution. But I think it's worth addressing, especially since people have asked about it before, and it fits into this model of the aquatic humanoid and creates at least a plausible

sounding scenario in which there could have been an aquatic humanoid. Yeah, if we entered into it as a as an alternate hypothesis, if we enter into it as a thought experiment, and we do not enter into it trying to make an argument for the existence of Triton's or or mer people or some sort of underwater race, then I think we're in safe waters. Okay, So it starts with a simple observation.

Our closest relatives in the animal kingdom are the other great apes, also known as hominids or the family Homonide. This includes orangutans, guerrillas, chimpanzees, and binobos, and genetically we are extremely similar to these animals, especially to chimpanzees and binobo's anatomically, we're also extremely similar to them. If you look at all of our body parts in the way they fit together. We're very, very close to these animals.

But there are a few key differences, and some of the most major of these key differences are that we are mostly hair us bipeds were naked, smooth skinned, and we walk on two legs. And meanwhile, all these other animals are hairy quadrupeds. They're covered from head to toe in in hair for and usually walk on four legs. So why that difference? What happened in the history of only the human branch of this family to drive our ancestors to become relatively smooth and bipedal while the rest

of our closest cousins didn't. Now just a note, I've often seen this framed in terms of questions like, quote, how did we get from chimpanzees to humans? That question is obviously nonsense, because we didn't get from chimpanzees to humans. Both chimpanzees and humans came from something that lived more than four million years ago. Chimpanzees are our cousins, not our ancestors. But the question is why do humans look different from them? And from every other hominid given that

were such close cousins. Well, in March nineteen sixty a British marine biologist named Alistair Hardy published an article and New Scientists arguing for a pretty startling answer to this. Hardy said, in the distant past, our ancestors distinguished themselves from the other great apes or the other great ape

ancestors by becoming an aquatic organism. So the idea here's our ancestors adapted to life in the water for a while and then return to land exactly, and that that shaped the differences between humans today and the other great apes. And so in this article, Hardy summarized his hypothesis about how quote man's immediate ancestors diverged from quote more ape

like forms as follows. My thesis is that a branch of this primitive ape stock was forced by competition from life in the trees to feed on the seashores and to hunt for food shellfish, sea urchins, etcetera, in the shallow waters off the coast. I suppose that they were forced into the water, just as we have seen happen

in so many other groups of terrestrial animals. I'm imagining this happening in the warmer parts of the world, in the tropical seas, where man could stand being in the water for relatively long periods, that is, several hours at a stretch. I imagine him waiting at first, perhaps still crouching almost on all fours, groping about in the water, digging for shellfish, but becoming gradually more adept at swimming.

Then in time I see him becoming more and more of an aquatic animal, going farther out from the shore, I see him diving for shellfish, prizing out worms, burrowing crabs and bivalves from the sands at the bottom of shallow seas, and breaking open sea urchins, and then with increasing skill, capturing fish with his hands. And of course this match is of the what we know about human cultures that have a legacy of existing close to the

sea and upon the sea. Yeah, now this is describing what we might call a semi aquatic existence rather than a fully aquatic existence. Right, So it's not that we became whales and lived entirely in the water, but that the hypothesis is that we sort of became like Homo beachkus, that we live adjacent to the water and spent a

whole lot of time in it. Homo biwa chicas like it. Now, this might sound crazy, and as we said, it is certainly not accepted by mainstream biologists or paleo anthropologists, but I want to say that there's nothing in principle wrong with the idea of a land dwelling mammal evolving to become an aquatic creature. We mentioned this earlier, but just to reiterate, like, where do you think whales and dolphins

came from? More than fifty million years ago, The ancestors of whales and dolphins were four legged, land dwelling mammals that went through many stages of evolution deeper and deeper

into the water. They started as these creatures that lived adjacent to the water and spent more and more time in the water over the generations, becoming more and more adapted to it, from the semi aquatic waiting lifestyle of pachactas and into high us to like this more otter like existence of this creature called ambulositis, and then eventually two creatures like the Dora down which start to look sort of like modern whales with eyes on the side

and the breathing hole dorsally migrated up toward the top of the head. And there's a similar story with pinnipeds like seals and sea lions. They're believed to have evolved from land dwelling quadrupeds that were something more like bears or musta Lloyd's meaning things like skunks, raccoons, or weasels. So evolution of land dwelling mammals into water dwelling mammals is not only possible, it has happened lots of times.

This is something that's totally biologically plausible. The plausibility of that scenario is not something that's necessarily a problem with the aquatic a hypothesis. The problems come in later because what's the real question, did it specifically happen to our ancestors? Right? Because if it, if it did happen, we should be

able to find some evidence of it. Right. So, as we said, this, this hypothesis is not popular with scientists and experts in the field, but it has really continued to capture the interest of the public since it was

first introduced. So it was first proposed by, as we said, the British marine biologist Alastair Hardy in nineteen sixty but it was really most popularized by a Welsh author named Elaine Morgan in the nineteen seventies and eighties, primarily through she She wrote about it in a book called The Descent of Woman, but then also in a book called

The Aquatic Ape. And so Morgan's argument for the aquatic ape hypothesis is interesting, and she she summarized it in a TED talk in two thousand nine before she passed away in two thousand thirteen. And so I think maybe we should look at some of the specifics of her argument. Uh so then we can. We can think about them and see how they stack up. All right, But before we do that, let's take a quick break, and when we come back, we'll dive in to the aquatic ape

theory some more than thank alright, we're back, alright. So Morgan's talk has a lot of framing material in it where she sort of lays the context for her argument by talking about the idea of paradigm shifts and science and about how scientific consensus has often been wrong in the past. That's absolutely true. Scientific consensus has very often

been disproved um. But one of the things I think we should be cautious about is when you start to hear somebody using that fact as an argument for their argument, if you know what I mean, it's often the opening argument of somebody who's about to lay some some some really fringe theory on you. Right, So, it is true that scientific consensus has often been wrong, but the fact that it has often been wrong is not evidence that your particular bucking of it is correct. Now, so what

is the evidence that Morgan presents for her hypothesis. Well, so, first of all, she looks at the really obvious thing. Where's all the hair, right, the naked skin. When you look for other mammals without body hair like us, they're almost all, she says, water dwelling creatures, the dugong, the walrus, dolphins, whales,

the hippopotamus, the manateee. Yeah. The only other example that comes to mind is, of course, the naked mole rat um, which is also kind of a special case given in it's a subterranean rodent that lives with a with a hive like structure. Yeah, she mentions it actually, uh, And then she says, wait a minute, wait a minute, what about the elephant. That's a land dwelling mammal without much

body hair? Well, Morgan says, it turns out that more recent studies have found that the elephant had an aquatic ancestor. I looked this up to make sure she's she's sort of correct about this. The elephants are related to an ancient mammal called the more ethereum, which apparently was semi aquatic lived in around swamps and rivers. Maybe not necessarily a direct ancestor of the elephant, but a very close ancient relative of elephants. She says, there's a strong correlation

between nakedness and water. There's some hairy or furry mammals that do live in the water, right, You can think of a few, Oh yeah, I mean the otters, beavers. If you want to make a stretch. You can even look at things like like the polar bear, which does is not an aquatic mammal per se, but does spend a lot of time in the water and is an

adept swimmer. Yeah, but there, She says. There are almost no hairless or smooth mammals that do not either live in the water or have fairly recent ancestors that lived in the water, and she claims that the only exception, as we mentioned, is the naked Somalian mole rat, which she says, quote never puts its nose above the surface of the ground. Then there's the question of bipedality, right, there's no real comparison in nature because we're the only

mammal that walks consistently on two legs. According to Morgan, all the things rear up at the time. You know, at times a cat will rear up on two legs and look exceedingly creepy, but that's at leg the rest of the time. Now that's mammals. Of course, once you start looking into birds and dinosaurs, of course you get basically humanoids by this characteristic. But the some four legged animals, of course, as we say, can occasionally stand up on two legs. When do our closest ape relatives walk on

two legs? Well, Morgan claims there's only one circumstance when they always walk on two legs, and it's when they're wading through water. You should remember that, because I want to take issue with that in a bit. Then she she marshals some more evidence. She says that how about subcutaneous fat. Morgan says, we have a layer of fat running underneath our skin and other great apes don't have this.

They're fat is stored more internally around their kidneys and so forth, and our fat is stored largely in this layer under our skin, similar to other water dwelling animals, kind of a blubber layer basically. Yeah, I mean, it's kind of an unfair comparison to make here, but we've all seen these images of a hairless guerrilla and they're just completely jacked, just conceedingly ripped in ways. It's like

hilarious muscles, comic book cover muscles. Yeah, that it is a comic book physique, and the kind of which you you rarely see in in the average human. Here's another one. She says, how about speech. This is a pretty big difference, right, Oh yeah, I mean that's one of the defining properties of of humans. Yeah. In fact, you know, there are a lot of people who would make the case, including

somebody we've had on the show in the past. Friends at evolved that a lot of the distinctions we try to make that really separate humans and other animals by some hard line of division, The lines a lot blurrier than you might think. But one thing he sort of made allowances for is maybe language that we that is the closest thing we've got to like a real edge on other animals. And so how come we can talk

and other hominids can't. Well, Morgan claims that the difference between a human and a gorilla is not in the speech producing organs of the throat and the lungs, but in the ability to consciously control the use of breath. And this is interesting to me because I think I've asked this on the show before. But why are some body processes controlled entirely by the unconscious nervous system while others are conscious and others can be toggled on and

off between conscious and unconscious control. Like you can't consciously toggle on and off your digestion or your heartbeat or your metabolism. But even though most of the time your breathing is unconscious and automatic, you can take it over with your executive control and consciously toggle your breath on

and off if you want to, like what causes this difference? Yeah, I mean, if memory serves me correctly, thinking back to our John C. Lily episodes in the past, uh, dolphins UH have such manual control over their breathing that they can arguably decide to just shut it down and to drown themselves. Wow. Well, I mean that would be an example that would sort of go with her hypothesis. Right.

The idea is that, uh, the only reason we would be able to evolve this conscious control of our breath is if our past ancestors were shaped by a selection pressure that favored the ability to like hold the breath and dive underwater. She says, This would explain a lot. I do think that's a really interesting question of why we can do that. I'm not sure I'm going to go along with her on this being an exclusively human

and aquatic mammal trait because I don't know. I've seen videos of dogs diving deep underwater and other mammals doing that. It seems that they have some kind of ability to hold their breath and they're not semi aquatic mammals. Yeah, I would agree with that. Okay, Another thing, she says, how about hydrodynamics. We are anatomically streamlined. Do you ever think about why is the human body basically a straight line? Why are we sort of dart ape where we can

dive smoothly into the water. She says, quote, try to imagine a guerrilla diving into water. I think I've seen it done in a cartoon, but that's about it. Well, they it's like a cannonball, right, they make a big splash. Morgan says, we're halfway between being a chimp into fish and so Morgan, after marshaling this evidence, she says that she wants to insist the idea is not lunatic fringe.

And I'd say I largely agree. I think it's probably wrong, but I don't think it's like the ancient aliens hypothesis or something. I think it is an extraneous hypothesis that that we don't really need to resort to, and so it's not parsimonious, but I think it's like reasonable to play around with this idea. Yeah, I would agree it is certainly not ancient aliens. But there are some some issues, some some problems, and some gaps that have not been

filled in by uh fossil evidence for example. Right, But the real question is like, what is the substance of the critique from biology and paleo anthropology. Why would they not accept this hypothesis. So, starting with a few answers, probably the biggest weakness for the hypothesis is and this might sound kind of silly when we say it, but there's no direct evidence for it. There's no fossil evidence

whatsoever that we've ever had any instance of an aquatic humanoid. Right, show me the remains of the aquatic humanoid, and it is the directive, and we do not have an answer. Yeah, nothing like that. Now, So this means it's all inference and speculation. It doesn't make it necessarily wrong because we're talking about the ancient past, and sometimes when we're trying to figure stuff out about the ancient past, we don't have direct evidence. Sometimes we're just in that situation and

all you've got is inference in speculation. So you just try to find the best most plausible inference and speculation to form your eye ideas around. But we have to acknowledge that there is no direct evidence for it, and so it's kind of in a weak starting place. Physical evidence would make a huge difference. Now. I came across another criticism of the aquatic aphypothesis by the paleo anthropologist

John Hawks of the University of Wisconsin Madison. UH. He runs a popular paleo anthropology blog, and he put a post on his blog about this idea. UH some of the points he makes are are pretty interesting. One of the things is that Hawks claims the aquatic ap hypothesis is not parsimonious. Now, parsimony refers to the idea of the number of assumptions you have to make without evidence

in order to entertain a hypothesis. So, for a quick example, imagine you leave a sandwich sitting on your desk at work. You walk away for a minute, you come back, there is a human bite shaped chunk of the sandwich missing. Okay, Now you look around, everybody's just working like normal. Noe, no direct evidence of what happened. So you have to make an inference. Right by the way, I am picturing

the scenario taking place in the movie Leviathan of those coworkers. Right, So, yeah, did did Daniel Stern take a bite out of your sandwich? Or what happened? Since there's no unusual behavior, no sign of anything wrong, you've just got to come up with

a hypothesis that seems reasonable. Now, you could hypothesize that Daniel Stern or another one of your coworkers took a bite out of the sandwich, or you could hypothesize that a polar bear snuck into your office undetected, and this was a polar bear that had undergone a surgical body modification so that its mouth had an uncharacteristically human shaped bite. And then it took a bite out of your sandwich with its surgical human mouth, and it didn't like it,

and it snuck away without being noticed. Yeah, that that explanation is is much further removed from reality and requires a number of different steps to get there. But like the aquatic a hypothesis, it's internally consistent, right, I mean, there's nothing on the face of it that makes that impossible.

It's just it requires a bunch of extra assumptions. Yeah, well, I mean, like one, it's basically like any investigation, right, Like, if you were investigating an actual sandwich incident in your workplace, it's far more likely that someone in the office did it than someone from a neighboring office who would have a harder time accessing the location in which the sandwich

is stored. Yeah, then you'd also have to hypothesize them sneaking in and all that, And like the further away you get from the sandwich from your office, they the

moral leap. It becomes. Right, So the main reason you'd favor the coworker hypothesis is that you have to make many fewer assumptions without evidence to assume it, and so at first glance, this kind of thinking can make something like the aquatic a hypothesis look good actually, because hey, wait a minute, it's just one assumption you have to

make in order to explain all this different stuff. But the more you examine it, the more it becomes clear that the aquatic a hypothesis actually requires a lot of assumptions of things not in evidence that just sort of

get rolled up into one big scenario you're picturing. You can say that all how about all evolutionary increments and all steps in evolution of all creatures are caused by the ghost of biology, which is a spirit that lives in the sky that decides that a creature should change and then makes little mutations to change it over time. That's just one assumption that explains absolutely everything in biology. But yeah, but it's a big assumption that that defies

or at least goes beyond the laws of science. It's like saying a ghost took a bite out of the sandwich. Yeah, it's only one step, but it's a step that that goes beyond uh, the scientific understanding of the workplace or the world itself. But then actually Hawks makes another point that I think is a crucial extension of this idea.

So it's not just what we've already meant and about some types of assumptions appearing parsimonious, but actually requiring a lot of assumptions even though they only seem to be one scenario. Hawks actually shows a second way that it's not parsimonious, and he writes, quote, certainly, it makes sense that hominids would develop new anatomies to adapt to such an alien environment. He's talking about adapting to the water.

But once those hominids returned to land, forsaking their aquatic homeland, the same features that were adaptive in the water would now be maladaptive on land. What would prevent those hominids from reverting to the features of their land based ancestors, as well as nearly every other medium sized land mammal. More than simple phylogenetic inertia is required to explain this, since the very reasons that the aquatic ape theory rejects the Savannah model would apply to the descendants of the

aquatic apes once they moved to the savannah. This is far from trivial, since fossil hominids did inhabit open woodlands starting by eight million years ago and did move to the open savannah by three million years ago. Okay, so the idea here is that want you could maybe reasonably make the argument that all right, the aquatic humanoids move out of the water, but they're still living close enough to the water. They're still going in the water. Uh,

you know, there's still a coastal species. You can say, well, maybe they retain some of those features. But if they're moving further inland, if they're becoming an inland species of savannah species, then they wouldn't need those adaptations anymore. The the the economy of natural selection would drive those away. Yeah.

One thing to be clear about here is that a very commonly still believed but actually now obsolete hypothesis is the idea that anatomical modernity in human beings evolved on the savannah, that we became basically the animals we are now on the savannah landscape. That used to be believed, and now that's not true anymore. What what generally is believed is that we became basically Homo sapiens in a woodland environment and in something you know, basically a tree

oriented existence, and then later moved to the savannah. Now, the aquatic a hypothesis is saying, no, somewhere in there before we got to the savannah, we were in the water if if that's true, though, we eventually moved back to the savannah, and these traits that we've still got had to somehow be adaptive to the savannah. So why aren't you just assuming that they're the traits that were adaptive on the savannah. Yeah, this is this is a strong point. Yeah, and so to continue, hawks says quote.

In other words, the aquatic ape theory explains all of these features, but it explains them all twice. Every one of the features encompassed by the theory still requires a reason for it to be maintained after hominids left the aquatic environment. So it feels like it becomes less of an exercise and explaining what we are with this aquatic explanation, and it becomes more about shoehorn earning the aquatic period

into our evolutionary history. Another thing I think we should do is just look a little bit closer at some of those individual planks of the argument that people like Hardy and Morgan brought up because a lot of them they sound so synsical, right, They sound very, very truthy at a distance, but they become a lot weaker, I think once you start looking up close at them. For example, the idea of hairlessness. Right, Morgan talks about the strong

link between aquatic existence in mammals and hairlessness. Now, first of all, I think it's worth pointing out that we are not hairless. It's true we do have hair, some more than others, but it's there. Yeah, our body hair coverage is not total. It's not nearly at the level of the other great apes, but neither is the body hair coat. You know, the body hair coverage of other great apes is also not total. Our hair patterns are different, but we do still have a pretty decent amount of

natural body hair. Also, the distinction between hairy land dwelling mammals and smooth aquatic mammals isn't a start stark, as Morgan suggests. Now, she does to be fair acknowledge otters and stuff like that, but there are also so many other hairy and furry semi aquatic mammals we mentioned furry beavers. But there's also the furry platypus, the water opossum, which is furry Alan swamp monkey, which is native Central Africa. It's covered in brown, gray and green fur. Semi aquatic cats,

semi aquatic her pestids like the crab eating mongoose. You've got polar bears that we mentioned earlier. You've got water diving bats. So a semi aquatic lifestyle clearly doesn't always lead to the loss of hair or fur. Furthermore, there are other hypotheses that could explain why we have relatively

less hair than our closest relatives. So there was an explainer in Scientific American where a researcher named Mark Pagel, the head of the evolutionary biology group at the University of Reading in England and the editor of the Encyclopedia of Evil Ouan, explained some recent thinking. One of the most common ideas about why humans lost a lot of their body hair has to do with thermoregulation. It says we lost a lot of body hair because we needed

a better way to keep cool. Now, this could have been a pressure introduced by other changes in our ancestors survival needs. Maybe if we migrated from a cooler climate like underneath a thick tree canopy to a hotter climate like an open, sun exposed woodland or savannah, we might need to lose the hair or if our survival niche became more oriented around intense, prolonged exercise, such as the prolonged chasing of prey animals. Yeah, exactly. Another explanation. This

one's pretty interesting to me. Parasite resistance. Oh yeah, because when you think of of animals with hair, you think of the various nasty parasites that can be crawling around in there. I mean, we've talked about the the extent to which mammalian especially i'mate social bonding is based around grooming, sitting around and picking stuff out of other people's hair. Yeah, and I mean you think of the constant thread of lice.

I mean, my child is in an elementary school, so that the threat of that the head life explosion uh is always there. Uh. So, by by losing the body here, we've kind of what driven the lice to the head in the pubic region, right. Yeah, I mean they should solve that by having just like grooming time where the kids sit around and pick lice out of each other's hair.

They probably go for that. So Pagel and a colleague named Walter Bodmer published research in two thousand three in Royal Society Biology Letters supporting the hypothesis that we lost our body hair to protect ourselves against parasites as as we all know, you know, ticks and lice and biting flies all they all make this happy home in thick body hair. They love it. And these ecto parasites are not only annoying, they can spread disease. Like we don't want our kids to get lice, but lots of these

kinds of parasites are are worse than lice. They can give you something that will kill you. Yeah, I just I'll direct our listeners back to our episode on on on ticks if you want some more information there. But here's something interesting to think about. Once our ancient ancestors could build fires and construct clothing, suddenly they just did not need as much hair to keep warm at night when it got cold. But the hair could still serve

as a refuge for these disease spreading parasites. So once you can build fires, and once you can wear other animal skins and stuff, is clothing there would have been a pressure against body hair, because body hair is this parasite vulnerability without much comparative benefit to make up for it. If you can keep warm anyway, why have this parasite

vulnerability hanging around. Yeah, Like when we were talking about aquatic apes supposedly returning to the land, like, I instantly thought, well, when I get out of a shower, I grab a towel. So perhaps you know, the naked ape emerges, it murders, a hairy animal of some of some form, puts on its fur. Like. It's one thing to think of that, but then this, the the use of fire technology would

be an even greater step. Yeah, so, Pagel writes, quote human lice infections, which are confined to the hairy areas of our bodies, seem to support the parasite hypothesis. Naked mole rats, animals that can be described as resembling quote, overcooked sausages with buck teeth, also seemed to support the theory.

They live underground in large colonies in which parasites would be readily transmitted, but the combined warmth of their bodies and the confined underground space probably negate the problem of losing heat. To cold air for these animals, allowing them also to become naked. So the same kind of like other warmth sources that could have selected for body hair loss in humans, can also select for body hair loss in naked mole rats. And then there's a totally different

kind of answer sexual selection. Sexual selection occurs when a pressure on some type of trait in the body is selected for, not because it provides a survival advantage, but because members of the opposite sex prefer to breed with people possessing that that trait, And so, like the peacock's tail, relatively smooth and hairless skin could have been selected for because it's a way to advertise to mates that you have good health and a lack of parasites. It's a

way of showing off that you don't have parasites on you. Yeah. I hadn't really thought about that, but but yeah, you have a hairless, shirtless hominid walking around it showing showing itself off and saying, look, do you how many bites do you see? How many? How many crawling parasites do you? Say? None? I'm a desirable mate, I'm in good shape. Here's the question. I actually don't know the answer to this, is there

a reason I can't think of Harry body Builders? Is that, like, is there a biological reason that like super muscle e dudes don't have hair on their chests or do they shave it off or what I think generally what's happening is they're they're having it waxed. Yeah, better off the muscles. I mean, there are plenty of muscular, hairy dudes. I mean, you can can do a search on that and you will get some answers. But but yeah, my understanding is that it's a it's about waxing of the body hair

so that you can show off the muscle. I'm just thinking about like the movie Pumping Iron, where there's just like it's just really really smooth. Oh yeah, yeah, you those guys are waxing in shave and I'm sure. Well, anyway, it's not clear to me that there's an obvious winner among the proposed ideas about how we lost our body hair.

But uh, any any of these are still viable ideas awaiting the arrival of new supporting evidence, And so I don't see a reason that the aquatic a hypothesis is like a better alternative that you have to go to now to address another plank. The argument the bipedality like that's also a great ongoing debate. The old theory, of course, was that we had to stand up to see over tall grass on the savannah. That's been debunked. Now we you know, we were in a more woodland type environment

when we when we evolved bipedality. But anyway, what made us stand upright in that woodland environment? Charles Darwin thought we might have evolved bipedalism to free up our hands for tool use. This seems unlikely since there's fossil evidence for bipedalism from before we have evidence of ancient tools. But there are other ideas like perhaps bipedalism emerged from a gathering lifestyle where our ancestors began to walk on

two legs so they could use two arms to carry things. Uh, this seems possible given observations that chimpanzees tend to walk on two legs and use two arms to carry food items that they consider rare or having great value. Now, going back to Morgan's argument about bipedality, she says, you know, wind to our closest tape, relatives walk on two legs. She said, as they always walk on two legs when they're wading through water, and that's the only time they

always walk on two legs. Uh, this is apparently not true because, as we've said, like chimpanzees will walk on two legs and use two arms if they're carrying something valuable. Also, I was like, well, let's let's see. I bet there's video of gorillas waiting through water on the internet. I looked it up. Uh, nope, I mean there are lots of videos of guerrillas waiting in the water, and most of the time they're doing it on four legs. I mean there are a few instances where they'd rear up

on two legs. Uh. So this doesn't totally disprove the hypothesis, but it really kind of undermines this plank of it. Well, I mean, it makes sense because if you're going into the water, there's a good chance you you want to

use your hands to feel for things. And granted, primates don't have exactly the same hand foot scenario is as humans, but you're probably going in there you want to feel the feel around for the rocks, You want to feel around for something that you're scavenging for, right, Yeah, exactly and so definitely li guerrillas will walk on four legs in the water. I've seen it. But I guess we have to come back to this question of like, obviously

we can't wholly judge. I mean, it's it's possible that something like the aquatic ap hypothesis has some grain of truth to it. But uh, if the biologists and paleo anthropologists are correct that this hypothesis is wrong, it's not not parsimonious, there's no reason to resort to it. Why is it so tenacious? Like we have had lots of people right to us and say, do the aquatic ape theory?

You know, we we want to hear about it. And it's not that I don't think it's interesting to talk about, but it's it's not really taken seriously by experts in the field. So why is it so captivating in the public imagination. Well, I think part of the answer is our entire first episode, where we talked about our mythological and fictional obsession with the idea of of humans that live in the water, a humans that live beneath the waves.

But there is a there is a deep cultural attraction to that idea, and it kind of bleeds over into aquatic a theory sometimes. I mean even even in cases when it's you know, it's not somebody saying, hey, I think mermaids are real and here's some science to pack it up, right. Yeah, it's one of it's kind of a sticky hypothesis. It's one of those things that, like I said, you know, I want to be fair to it.

I don't think it's like lunatic fringe. I don't think it is ancient aliens, but I don't think there's a good reason to resort to it. But it's one of those things that's just so interesting to the mind. It's so fun to picture and so fun to entertain that it's sort of like overrides our sense of disinterest in

other things that seem, you know, not necessary to believe in. Uh. There's actually a paper from nine in the Journal of Human Evolution by John H. Langdon called Umbrella Hypotheses and Parsimony and Human Evolution a critique of the aquatic a hypothesis, and Langdon talks about this idea of these umbrella hypotheses, which he says, our quote aesthetically a peeling because they appear to be parsimonious, so they're internally consistent, and by

offering this one umbrella hypothesis that explains a range of things, and they appear to explain a whole lot, as we were talking about earlier, without making you, without requiring you to assume a whole lot, but they actually are requiring

you to assume more than they appear to. And so, in trying to explain why these types of ideas stay popular with the public, he says, quote one reason for this is that simple answers, however wrong, are easier to communicate and are more readily accepted than the more sound but more complex solutions. Evolutionary science must wrestle with this problem, both in its own community and in the education of

the public. I agree. I mean we see we see this time and time again, and it reminds me of ongoing discussions regarding climate change, which we've discussed on the on the show, and just sort of the challenges of science communication in general. Yeah, there are so many ideas that just because they're simple to communicate and easy to say and easy to remember, they there's almost like a

survival advantage they have. There's like a selection pressure against things that are hard to explain, and a multiplication incentive on ideas that are interesting visually to imagine and have sort of like the the truthiness feeling, the feeling of explaining a lot, and are easy to communicate, And I think the aquatic a hypothesis falls in that category. Yeah. Like, for instance, I come back to what a physicist Brian Green said about climate science and the most recent World

Science Festival in New York. He talked about how he decided, right, I'm gonna do it. I'm gonna bone up on climate science so that I can talk about it and defend it. And he just he gave up on it because and this is a this is a lifetime of work. It's a lifetime of work, and this is an accomplished physicist saying yeah, I can't I can't get up to speed on this in the way that would be required for me to go to bat for it against climate change

deniers and so forth. So but on the same hand, it seems like it would be it would be far easier for Brian Green, uh, for you or I as well to bone up on aquatic ape theory. You know, if someone said, all right, Joe, you're going on Fox News tomorrow to defend aquatic ape theory. I could do it. Yeah, I mean I wouldn't want to, but I could do it. It's gotten his favor, that truthiness gravity. Yeah, all right

on that. Now we're gonna take a quick break and when we come back, we're gonna talk to genetics a little bit. All right, we're back. Hey. You know so in the break, I was just thinking about this. Uh, I wonder if I have aquatic humanoids, if this, if this words true, would they have an easier time urinating in the water. Best off conversation ever, No, I know what you're talking about. Like you can kind of when somebody's peeing in the water, you can, like you were saying,

you can see it on their face. Yeah, there's a look, there's a there's kind of a stillness to the body. I mean in my own case, like if I'm not in the pool, but if I'm in the ocean or something, I feel like I I have a I have to really go into a certain um, you know, state of mind to pull it off, and I'd probably look like

I'm peeing in the ocean. Thanks a lot, Robert colluding the ocean for the rest of us, well, you know, the fish do it, the mr folk do it, So you know, why should I have to walk back to the conduct. I know exactly what you're talking about. There's this kind of like, uh, you see people with like the the kind of the eyes roll up and they

kind of tents up and grit their teeth a little bit. Yeah, So I wonder if if this would be something, if this would be in favor of the aquatic ape, like it's something that we lost we would have lost upon returning to land. Or is it just evidence that we were never uh, some sort of an aquatic committed species that was totally at ease peeing in the pool. Okay, let's get beyond the aquatic ap hypothesis, which imagines this semi aquatic uh period in in human history. As as

we've said, we're not convinced by this idea. It's not absolutely impossible, but I don't think there's a good reason to go there. However, if we want to entertain the idea of a totally aquatic humanoid, a humanoid of the deep, what would we be, what would we be looking at? What would that entail? Well, I suppose there are basically two ways to look at it, right, either something humanoid evolves independently of humans in the deep, or a hominid

variety splits and evolves into a primarily aquatic species. Okay, so this would be an example of either convergent evolution where some kind of aquatic species converges on basically the humanoid form, or it would be a divergent but basically the same kind of thing we see in the evolution of whales and dolphins. They were land dwelling mammals, then they became semi aquatic mammals, and then they became totally aquatic mammals. Right now, I think the idea of covergent

evolution in the deep. I mean, I can't think of anything that that lives is a primarily aquatic lifestyle that looks anything like a human being. Sometimes you get some kind of creepy human behavior convergence with octopi. That's true. I'm sorry, I said octopi. Octopuses, Yeah, there there are there are some some cephalopods that have kind of a walking technique on on the bottom of the sea. There are some fish that quote unquote walk on the bottom

of the sea. They move around with their fins. But that's a far cry from having something that that really has anything like a human body like even in just you know, very broad strokes. You know, we've touched on a number of the different examples though, of of of creatures that have got the other direction, mammals that have

returned to the sea. But I think perhaps the manatee and its skin are our best examples to look to for you know, for what for what a creature like this would would be, what what an aquatic humanoid would consist of? Right? And you know, we called them the Sirenians for a reason. It's ironic that these these are creatures that partially inspired our visions of mermaids. So we're talking about the manates here and the doo gong. Uh. They're the world's only marine mammal herbivores, and the only

her herbivorous mammals ever to have become totally aquatic. I've never thought about that, the only marine mammal herbivores, while all the others eat eat the flesh. Yeah, even if it's very tiny bits of flesh, very tiny creatures, they're still eating creatures. So Sirenians have existed for more than fifty million years, having diverged from the Panugu lata clade. The closest living land relatives to the Sirenians are the

elephants and the high axes. Now a, this is a pretty interesting In two thousand and sixteen, studied by Maria Hikina and Nathan Clark looked at three major independent evolutionary events in which mammals returned to the sea and what sort of evl utionary tradeoffs took place. So they used a fifty nine placental mammal genomes to calculate the relative rates of evolution for all branches. In eighteen thousand and forty nine gene trees, they calculated a genome wide average

rate of evolution across all species. Basically, they wanted to see if these uh oceanic returns entailed and evolutionary acceleration or deceleration. That's interesting. So they identified three main themes a burst of adaptation, then relaxation, and additional constraint. They identified marine accelerated genes to the tune of about nine percent, and they related to these different features new functions for genes forming skin and connective tissue, sensory systems, muscle function,

skin and connective tissue lung function. So an example here would be accelerated adaptation for a gene encoding a lung surfactant protein that may have been necessary for diving, and then lipid metabolism. But they also identified marine decellered accelerated genes even more than the you know, the accelerated and these related to a general loss of the number of sensory genes for smell and taste. No, no more taste

once we got in the water. Yeah, I mean, it's it seems to be the case that that aquatic mammals have have a much decreased sense of taste. So I guess once you're a sperm whale and you're like trying to eat giant squids, you just don't want to be tasting that well, uh, something like that. Now. Other marine decelerated genes included molecular molecular maintenance strategies such as DNA repair,

chromosometal maintenance, immune response, and program cell death. So all of this, they said, meshes with the increased constraint on somatic cell maintenance for such creatures. And I have a quote from the paper here, quote hundreds of genes accelerated their evolute sctionary rates in all three marine mammal lineages during their transition to aquatic life. These marine accelerated genes

are highly enriched for pathways. The control recognized functional adaptations in marine mammals, including muscle physiology, lipid metabolism, sensory systems, and skin and connective tissue. The accelerations resulted from both adaptive evolution as seen in skin and lung genes, and loss of function as in gustatory and olfactory genes. In regard to sensory systems, this finding provides further evidence that reduced senses of taste and smell are ubiquitous in marine mammals.

So naturally, this is not a blueprint for evolved aquatic humanoids, but I think it does give give us some sort of idea of the genetic changes that might take place over millions of years until we reached the point that we're Kevin Costner from from water World. But but how do we reach the point that we're Dennis Hopper in water World? Well, all I can say is that Kevin Costner's character or would probably not have a good sense

of taste based on this research. It's a bummer man. Yeah, All right, So let's come back to the reverse though, something from the deep evolving to life on the surface. This is of course the story of all terrestrial life, dating back to the terrestrial land invasion of the Devonian era. But when we try and think of a humanoid creature evolving under the water, it gets a little sticky. We get into the creature from the Black Lagoon territory, we get into uh Z or Bloodwaters of dr Z territory.

Because in these cases uh they often will bring up certain fish that can walk on land as examples of of how this might work, or fish that can breathe both above and below the water. And we do have ambulatory fish walking fish such as the mud skipper. We have that the hand fish and frog fish, which quote unquote walk on the seafloor with specialized fins, and of course they're the there's the walking catfish of Southeast Asia, which we should be clear does not so much as

walk as it flops and flips and wriggles around. And uh the lungfish, the fish highlighted in the creature movies. This creature does boast a lung and gil combo existing as a sort of call back to the three seventy five million year old evolution of landwell and creatures from a long extrict species of lobe thin fish. But it still doesn't give us quite the recipe for a gill

man that we would we would like. Yeah, there are a lot of problems I can see here for a humanoid evolving in the water itself, I mean bipedality, whatever you want to think about it, like, even if you're still attracted to the aquatic a hypothesis, um, which I don't necessarily think you should be. But even if you're attracted to that, it says bipedality was sort of a transitionary feature, right, It was a product of wading in maybe deep water, but not totally deep water, not like

water deeper than you could stand in. And so having like a bipedality and legs is not really useful if you are a fully aquatic creature, you would eventually lose them. It would be much better to have fins, right, Well, I get The only case I can see to be made here is that the creature from the Black Lagoon must come out of the lagoon to acquire prey and of course women. But but you know it, it is

it is not an obligate um marine creature. It is a creature that that that must come out of the water to prey, a creature that is perhaps in the process of becoming a land creature. So yeah, almost anything you could think of as a humanoid in shape at all would really need to be semi aquatic, right. It would need to be at least or mostly aquatic. It would need to have some reason to come out of the water if it was going to have legs like human legs, because legs are made for for fighting gravity.

Legs are not made for swimming around in a you know, in a buoyancy situation. That's true. And if you don't have a switch to magically turn your fins in defeat, then you're probably out of luck. Yeah. So I think if there were an aquatic humanoid, it would more likely be a mermaid with a fish butt than a humanoid like the gill man with legs, I think. So. I

think that makes the most sense. In fact, since they spend most of their time under the water, even if they did come out of the water, what I guess is that would be a mermaid with a fish butt that would crawl around with its upper arms. Yeah, and we do see that model sometimes the what is it the Cabin in the Woods movie? Oh yeah, I had a had a Merman creature that comes comes crawling across

the floor after its victims. Here's another question, though, how do you think if there were such a thing as an aquatic humanoid, how would tool use evolve differently at the bottom of the ocean. Oh yeah, that brings us back to some some discussions with out in the past, particularly as it pertains to the use of fire technology and the idea of any technology existing without fire. Um.

I mean I keep coming back to. I guess it would a lot of it would have to be sort of biologically based, you know, I mean you could would it would it could not be fire based because you you cannot really have fire under water. I mean, you see some things that get kind of classified as rudimentary tool use by by like octopuses right where they I mean, maybe this isn't tool use, but the idea of like pulling a rock over the entrance of their dwellings they

can cover it up and protect themselves. That that's interesting behavior. Yeah, I mean that's the use of I believe the distinction is that's a nature fact, that is taking something in nature and using it for purpose. Now and then you could say, well, I can imagine an underwater humanoid making an artifact, taking something and sharpening it into a skewer or shaping it to better protect them, so that that

level of technology I could I see. I mean one thing though, is that under the water, both the resistance density of the water and the buoyancy effects all would kind of mitigate against some of the benefits you get from say stone tools are our most basic tools are very often things that are designed to maximize kinetic energy delivery, right, So it would be something that you could throw really hard and hit something and kill it, or something that

you could hit another thing with and break it, and kind of a gravity assisted swinging motion, all of which is a little bit harder to do underwater because you can't swing as fast underwater do the resistance of the water. I mean, I don't know. I wonder if you could have a tool using creature evolve under the water. Well, more than more than likely you have to depend upon

them originally being an alien species crash landed in the water. Um. Yeah, this is reminding me a lot of the the old nautical maps which were on which you had mermaids and sea monsters, but also all of these different hybrids. Sea lion, a sea lion that is not like our sea lion, but an actual lion with a fish uh portion to

its body. And a lot of this was based on the idea that the ocean contains a parallel version of everything that we have on the surface and it and you can extrapolate that to include not only the animals but the resources, and say so you end up falling into the trap of thinking, well, the underwater creatures they would have their own minerals somehow, they would somehow, you know, smelt them and and craft them into weapons. Without really

thinking about it. That the the the aquatic world is, it's a part of our world, but is a very different, very alien environment compared to the surface. Yeah, it's not exactly the mirror world. It's more through a glass darkly all right. So there you have it. Uh. In these two episodes, I hope we've we've given everybody a lot of fresh perspective to consider not only the evolution of humans maybe, but but also just our our myths, our

fictions regarding underwater people and underwater hybrids. And of course, we want to hear back from everybody concerning their favorite uh underwater humanoids in myth in UH in literature and cinema. What's your favorite nine Underwater Peril movie? Totally? I know we've got some deep Star six partisans out there. Yeah, I think people get attacked. What is it a killer clam or something in that movie? It's I haven't rewatched it yet, um, but it's some sort of an underwater

critter yeah. Um. Oh. And also Mermaid movies? What's your favorite did you like? Did you grow up like me watching Splash on VHS over and over again? I didn't know that about you, Rob. Yeah, it's a solid mermaid romantic comedy. Okay, I'll have to check it out. Yeah, yeah, Tom Hanks, Darryl Hannah, John Candy, tremendous. Did they ever do a Jetson's Meet the Flintstones kind of thing with Leviathan and Splash with Leviathan? Oh? You mean did Leviathan

meat Splash movie? I don't think it exists, or at least not yet. Movie executives, high powered industry players out there, if you're listening, take note. Yes, opportunity knocks, all right, Hey, In the meantime, check out stuff to Blow your Mind dot com. That is where you will find all of our podcast episodes. You'll find blog posts and other material as well. Links out to our social media accounts will be found on that page. Also, so we're talking about Facebook, Twitter, Tumbler, Instagram,

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