From the Vault: Aquatic Humanoids, Part 2

part of our our look at Aquatic Humanoids. This is from January, and it's a look at everything from the Sirens of the Odyssey to the creature from the Black Lagoon, the Guild people from the the HP Leftcraft stories, and it's going to get into territory explored by the recently published sci fi podcast Transgenesis, which I wrote and created along with the help of Alexander Williams, Lauren Vogelbaum, various folks here at how stuff works in some very talented

people from outside the organization as well. Joe shows up in the show at one point. I think I make a creepy camey. You do, you may make an extended creepy cameo. All ten episodes are gonna launch at once, so that you can you can binge them. You can, you can, you can spread them out over your commute, you know, however you want to do it. You can

also find it online at Transgenesis dot Show. But it's a sci fi podcast that has certain things to do with the idea of deep sea intelligent life, deep sea human ooid creatures, and that's the kind of thing that we explore in this episode of Stuff to Blow Your Mind. That's right, So, without any further ado, I say, let's go right to the episode. Welcome to Stuff to Blow Your Mind from how Stuff Works dot Com. Hey, welcome

to Stuff to Blow Your Mind. My name is Robert Lamb and I'm Joe McCormick, and today is going to be part two of a two part episode about the aquatic humanoid. Now, last time we really focused on the mythology and cultural beliefs about our aquatic counterparts, the humanoid types who live in the depths and there this is a trope all throughout fiction. You find it in all

kinds of human cultures. 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 Leviathan. 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 ninety 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 sort of trying to piece together in a casual way. Why that was, you know, what what was happening in the world was it did have to do with that, 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 preyest 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. Uh, it is a thoroughly enjoyable, flawed film. It's this 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 says alien underwater that's the poll quote. Yeah, it is highly derivative. But 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 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 back story 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 sleeves and obnoxious nous. 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 going to 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 are 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 etheo centaur, of 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 at fish head and then it's got Daniel Stearn's face sticking out of its back and some other random tentacles and lampreys 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 aquatic 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, the you know the 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, yes, not like not like Mermaid top with guerrilla legs. No, no, no fish fish on the bottom. Uh, silver back 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 hamanids or the family Homonida. This includes orangutans, guerrillas, chimpanzees, and binobos, and metically 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, were 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 hairless 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 human ends. 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 returned 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, et cetera. 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 matches up 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 beachicus, that we live adjacent to the water and spent a whole lot of time in it. Homo beach bummocus, Homo biwa chicas. I 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 pacacidas and into high us to like this more otter like existence of this creature called ambulositis, and then eventually two creatures like the Dora don 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 ape 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 more. His argument for the aquatic a 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. Thank thank alright, we're back, all right. 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 the 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 doo gong,

the walrus, dolphins, whales, the hippopotamus, the manateee. Yeah. The only other example that comes to mind is, of course the naked mole ratum, which is also kind of a special case given in it's a subterranean rodent that lives with a with a hive like structure. Yes, she mentions it actually, and then she says, wait a minute, Wait a minute, what about the elephant. That's a land dwelling

mammal without much body hair. 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 are 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 adapted 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 except and 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, Yeah, you know, at times a cat will rear up on two legs and look exceedingly creepy. But but that's about it. It's four legs 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 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? Will 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 gorilla and they're just completely jacked, you know, they're just exceedingly ripped in ways. It's like hilarious muscles comic book cover muscles. Yeah, that it is a comic book of 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 the 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 linees 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 guerrilla 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 heart beat or your metabolism. But even though most of the time you're 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. Yeah. 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 trade 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 shaped where we can dive smoothly into the water? She says, quote, try to imagine a gorilla diving into water. I think I've seen it done in a cartoon. But that's about it. Well, it's like a cannonball, right and 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, and it straineous 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, yeah, I would agree it is certainly not ancient aliens. Uh, 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 and speculation. So you just try to find the best most plausible inferenceance speculation to form your 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 a hypothesis 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. No, 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, that 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 co workers 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 and 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 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. Right, And like, the further away you get from the sandwich from your office, the more to 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 bit 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. 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 mentioned 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 return 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 woodland 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. There's 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 in some 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 exp blaines 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 shoehorning 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 as 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 Evolution 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 a 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 primate social bonding is based around grooming, sitting around and picking stuff out of other people's hair. Yeah, and 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 lies 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. Kids are chriss So Pagel and a colleague named Walter bottom Or 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. They all make this happy home in thick body hair. They love it. And these ectoparasites 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 the naked ape emerges, it murders a hairy animal of some pomp 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 seem

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, could 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 so 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 mean good shape. Yeah, here's the question I actually don't know the answer to this. Is there

a reason I can't think of hairy 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, so they can better show off the muscles. I mean, there are plenty of muscular Harry dudes. I mean you can do a

search on that and you will get some answers. But yeah, 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 Shathan. 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 of 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 says, 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 wading 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 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 guerillas 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 ape 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 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, 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 aight 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

there 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 esthetically appealing 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 accept up to 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. It reminds me of ongoing discussions regarding climate change, which we've discussed on 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 climb it 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. Yeah, it's gotten his favor,

that truthiness gravity. Yeah, all right, And then now we're gonna take a quick break, and when we come back, we're going to 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 works true, would

they have an easier time urinating in the water? Best off my 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 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, themur 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 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 that we would have lost upon returning to land or is it just evidence that we were never uh some sort of an aquatic commoned 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 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 involves 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 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, I've 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 an aquatic humanoid would consist of? Right, And you know, we call 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 manatees here and the doo gong. They're the world's only marine mammal herbivores, and the only herbivorous mammals ever to have become totally aquatic. I've never thought about that, the only marine mammal herbivores. All 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 pan Galata clade. The closest living land relatives to these Iranians are the elephants and the high axes. Now a, this is a pretty interesting In two thousand and sixteen study by Maria Hikina and Nathan Clark looked to three major independent evolutionary events in which mammals returned to the sea and what

sort of evolutionary 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 identical fied 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 uh surfactant protein that may have been necessary for diving,

and then lipid metabolism. But they also identified marine deceller 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 get 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 thing like that. Now, other marine decelerated genes included molecular molecular maintenance strategies such as DNA repair, chromosomal 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 evolutionary 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 muscles, 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 mammal 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 reach the

point that we're Kevin Costner from from water World. Yeah, 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 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 u Z or Bloodwaters of dr C territory. Because in these cases, uh they often will bring up certain fish that can walk on land as examples of how this might work, or a 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 the the hand fish and frog fish, which quote unquote walk on the seafloor with specialized fins. And of course there are 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. Uh, 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 land oil and creatures from a long extic species of lobe fin 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 water, I'd guess is that to be a mermaid with a fish butt that would crawl around with its upper arms. Yeah, yeah, we do see that model sometimes the what is it happened in the Woods movie? Oh? I had a had a mirman creature that comes comes crawling across the floor after it's 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 we've had 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 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 them selves. 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 a 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 could 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 to 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 in 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 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. Yeah. All right, So there you have it. 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 o our myths and 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. I think people get attacked. What is it a killer clam or something in that movie? Uh, it's I haven't rewatched it yet, um, but it's some sort of an underwater critter.

Yeah yeah um. And also Mermaid movies. What's your favorite did you like? Did you grow up like me watching Splash on VHS? Over into over akend? I didn't know that about you. 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 Leviathan? Oh you mean, did Leviathan Meet 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 that, blog posts and other material as well. Links out to our social media accounts will be found on that page. Also, we're talking about Facebook, Twitter, Tumbler, Instagram, We're on all those things. Follow us where you will.

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