Creature with the Crystal Skin

other body parts. Yeah, and just thinking about this topic brought me back made me think about some stories that I probably haven't read in about twenty years now, but the tales of Fritz Lieber genre Ryder, who lived nineteen ten through fun Note he was the son of actor

Fritz Lieber, so he's technically junior to his senior. Fritz Leeber Senior was in films like nineteen threes, Phantom of the Opera starting Claude Rains, and then Fritz Lieber junr Son Justin Lieber was a philosopher and a sci fi author in his own right. I think at some point I just popped open his Wikipedia page, and I saw there was a top line reference to him also being, in addition to being like a sword and sorcery author

and science fiction author, a chess expert. And that was one of those things where I was like, is that real or is that just like something that that the author themselves or someone associated with them kind of snuck in there. I don't know, I'm not I'm not ass up on the full Fritz Lieber biography there, but but he wrote a lot of stuff in various genre works. Some of his stories even were also adapted into I think like a couple of episodes of Night Gallery back

in the day. But the closest, the thing that's closest to my heart, the material that I'm familiar with, are these stories he wrote about these two characters, uh Fowford and the Gray Mouser. Uh So this is your sort of iconic adventuring duo, and he's these stories helped him make it iconic. You have a pair of barbarian in a rogue and they get into all manner of adventures. These were these were very popular stories. I think they had an influence on the development of dungeons and dragons,

and they hold a hold up pretty well too. Well, if it's a barbarian in a rogue that sounds like Conan and Subatie, Yeah yeah, yeah, very much of that vein um so that they're great fun. They're always encountering various enemies and magic and magical creatures. And in one work in particular, I believe this is The Swords of Lankamer from Night, they encounter ghoules. Now, I love ghoules

as they appear in various other works of fiction. Uh, these goals are very or rather different, and I think when I first read Fritz Lieber's ghouls, I was a little I wasn't mad into him. I was like this, this is this is a little too different from what I'm used to. I just want, you know, bone chewing pallid humanoids, because he takes the idea in a in a rather different direction. Okay, so your standard ghoul is just a sort of deathly looking humanoid who hangs out

in graveyards and eats grave flesh, right right. These ghouls have translucent anatomy. Essentially, they just look like a walking skeleton because all of the soft tissues in their bodies are transparent. So the only thing you can actually see is the skeleton unless like the light is just right, because you know, it's not true and it's not magical invisibility. It's supposed to be uh, you know, translucent tissue based invisibility, so you would only see the skeleton in most cases,

though there is more than the skeleton. They've got some some fleshy, soft, squishy bits, but those those just let the light pass right through. Yeah, everything is see through

except for the skeleton. So I actually just want to read a little bit from the Swords of of Lachmar from After an instant and shock, Fawford realized that these must be ghouls, whose flesh and inner organs he had heard with much skepticism, but now no longer were transparent, except when the skin became slowly or rosalie translucent on the genital organs or on the lops and small breasts

of their women. It was said also that they ate only flesh human by preference, and that it was strange, indeed, to watch the raw gobbits they gulped, course down and churn within the bars of their ribs, gradually turning to mush and fading from sight as their sightless blood assimilated and transformed the food, granting that a mere normal man might ever have the opportunity to watch Ghoule's feast without becoming a supply of gobbitts himself. That is some pros. Yeah, yeah,

it was a good good writer. There's there's a lot of fun and whimsy too. Um So, the ghouls in this story they described themselves as being crystal fleshed and h and that they see it as a sort of sacred responsibility to consume the flesh of say, human beings, because our flesh is um is murkier, you know, it's it's not that translucent purity. So when they eat it, uh, they eat our flesh, it eventually becomes translucent, It becomes

crystal inside of them. There's a female ghoul that pops up in these stories that the believe of Fafford actually ends up falling for after a while. And she also has a great story about ghoul romance. Yeah yeah, google romance. Uh. But there's a bit where where she's talking about like the differences between um between ghouls and humans and she tells him bones are beautiful, they're made to be seen.

And there's another part where Faford asked his asking questions about what's it like to be a ghoule, and he picks up on a bit of a scientific critique that often comes up when discussing things like HD Wells Invisible Man. He says, well, how can you see anything if light passes right through you? He asked her if ghoules happened to see with the inside of the back of their skulls, and she responds, quote, look closely into my eyes, No,

without getting between them and the fire. Can you see a small rainbow in each That's where the light is refracted to the seeing part of my brain and a very tiny real image formed there. I love alternative visual anatomy. That's great. Yeah, I love that he made sure to actually throw that in there to address how his ghouls see anything. But anyway, like I said, when I first read of these creatures, I was I was like, oh, this is too different. I these are not googles I

can really get behind. But now, as we're about to jump into the discussion of some amazing natural world organisms that have various levels of translucency to their bodies, I'm looking back on Fritz Leeber's ghouls and I'm like, these are amazing. These ideas of these uh, these translucent fleshed beings like jumping into battle with their axes and everyone on the other side they just look like skeletons because

that's the only part that isn't see through. That is great. Okay, well, I guess the first example of a of a real animal I want to talk about today a group of animals actually known as the glass frogs, and a little bit of terminology distinction. I guess we've already said these words.

But um, but transparency versus translucency if you're not familiar, Transparency you can think of as being clear like glass, pretty much allowing all light to to pass through, whereas translucency you can think of like frosted glass, is allowing a lot of light to pass through, but not as much as as a total clarity. You'll find that these

are though sometimes used interchangeably, even sometimes in scientific papers though. Yeah. So, the so called glass frogs comprise many different species, but they all belong to the family central in a day, which is found in regions throughout Central and South America. These are mostly arboreal creatures, meaning they live in trees, often in rainforests and especially near sources of fresh water. So if you want to find a glass frog, most of the time a good place to look it's like

on leaves overhanging the bank of a jungle stream. But if you were to go out looking for one of these creatures, you might have a bit of difficulty. The difficulty finding the frog even if you're looking right at the leaf where it's perched, because glass frogs can blend in very well with foliage, and Robbi attached a couple of pictures for you to look at here of various green and yellow species of glass frogs perched on a leaf.

It's especially good to look at like a leaf that's sort of lit from behind, and the frog will be right next to a collection of what looked like little semi transparent, semi opaque spherical globules, And these are actually the frog's eggs. One of the most striking things about

the glass for family is their skin. Now, most species of glass frogs appear from above to have a kind of uh moderately translucent skin, especially on some parts of their their dorsal sides, such as like the toes or the legs, and so you can see the blurry specter of bones in their toes or in their legs, which is very creepy and very cool that this this would be like crystal ghoules. You can actually see the bones

through the skin. Some species take this even further and have not only semi translucent legs or parts of the backs, but nearly totally transparent bellies. So this would be the

belly the ventral side. Again not all species, but with some it can be almost as clear as glass, and you can look through and see their internal organs in full color, including a little tiny beating heart and a big thick red artery going down the middle of the of the inside of the stomach, big coiled white massive intestines, and so forth. I mean they remind you of the

visible man and the visible woman anatomy kits. I think we we all grew up with, uh, you know where you have the plastics see through skin, and you have you you put all the little organs in there. It's it's like this frog, isn't it to be an anatomical education tool? Now? Another feature only tangentially related to their

transparency or translucency. If you've ever seen the Planet Earth feature on glass frogs, it includes at least one species of glass frog that shows this amazing egg defense behavior. So with these frogs will often happen is that there will be a clutch of fertilized eggs sticking to the side of a leaf that may be hanging above the water, and there will be a father frog guarding the eggs.

These eggs are apparently a favorite food of local carnivorous wasps that will kind of zoom in and try to you know, munch on them and pull the pull a partially formed tadpole out of the egg and take it away to eat it. But the frog fathers actually defend their eggs literally by kicking the wasps, which is amazing

to watch. You should look up this clip. Yes, I was watching this earlier as yeahs, As is often the case with Planet Earth footage, very impressive, gorgeous to watch, but it also really drives home how much the glass frog looks like a clutch of eggs on the back of that leaf. Yes, they often have marking or coloration patterns on their backs. That makes the adult male frog look like a clutch of eggs itself, so it just kind of blends in and then when the wasp gets close,

it kicks. One of the amazing things is seeing So it's this tiny little frog and a lot of these, uh, these frogs are so small. They might be just a you know, the size of the size of a finger tip, maybe a couple of cinameters. I mean, they vary in size with different species, but most of them are very small. But then when you see that leg suddenly launch out like a spring, it's like enormous that it's an incredible

how far it reaches. But to come back to the glass element of the glass frog, what is this translucent or in some cases nearly transparent skin. For why would it be of evolutionary benefit to this frog to to have parts of its body being almost clear? Well, I think for a long time it was presumed to have some kind of role in camouflage, but we didn't really

know for sure. But there was a paper published in by James B. Barnett at All in uh Proceedings of the National Academy of Sciences called Imperfect Transparency and Camouflage in glass Frogs, And this was really interesting. It did some experiments to try to look at the translucent inin of a glass frog and say, what does it actually do in practice, like does it work as camouflage and if so, how Now They start by giving some background

on biological camouflage in general. For example, camouflage patterns on animals can can help in multiple ways. They say they can prevent both detection and recognition, so you can imagine those is two slightly different things. Preventing detection might mean that a predator doesn't notice you at all, like they don't see that you're there, whereas preventing recognition might mean that if the predator sees you, it doesn't recognizize you as what you are, maybe you look like something else.

And the authors mentioned that there are multiple ways camouflage works. It can work by say, matching a background, and there are lots of examples of this. But you can think about a moth or a butterfly that has patterns and coloration on its wings that resemble the patterns and coloration of the bark of the trees. It lands on the tree, and it just kind of blends in. Another thing would be mimicking particular background features, trying to trying to recreate

textures that would exist in the background. And another thing would be disrupting or breaking up edges trying to have patterns that make it harder to tell where the outline of an animal would be. But they raise an interesting question. What if you're an animal that lives in a habitat where you can't always predict an advance, what kind of background you will be the foreground of What if you're a vulnerable creature that needs camouflage but you live in

a highly variable environment. Evolution has at least one solution to this, which is active color change. So, uh, we've talked about this on the show before, but think of octopuses with their chromatophore cells that allow them to shift colors and blend in with seaweed or rocks or the sandy floor of the ocean. There there are tons of amazing videos of this. You can look up where you know, you wouldn't even see it, Like an octopus just lands among some rocks or some coral or seaweed or something

and it just becomes them. It's amazing. Yeah. I just, uh, almost a year ago, I got to observe an octopus in the wild and in Hawaii and uh yeah, it got to watch it do this. It was amazing. Like one of these situations where you watch it go to some rocks or a bit of coral blend in. And since you've been watching it, you can still make out where it is. But if you move your eyes away from it from just a step for just a second and then come back, uh, you can't see it anymore.

It's still there right in front of you. But the camouflage is so perfect. Uh, it's just quite amazing to behold totally. And another classic example one probably everybody is familiar with chameleons. They can change colors to match background, uh,

the surfaces in order to better blend in. But of course having something like chromato four cells evolving this capability is is of course a very niche evolutionary specialization, so you need that that history feeding into it is also of course biologically costly, and the authors point out that the efficacy of active color change can actually be limited

by things such as the range of patterns available. So an animal that can actively change it's it's markings and color patterns can't do that to an infinite degree of flexibility. You know, it's still it's going to have surface features and colors and and like it can change somewhat, but it can't look like absolutely anything, right. And another thing is the speed of change, So it takes a minute. You know, you can see this even with octopuses that can change very fast, but it still takes a few

seconds sometimes. So is there any other way to blend in with your surroundings? Well, what about transparency. Transparency, of course has the ability to create very high fidelity camouflage because you can literally see through to the background. They can match anything in the background. There's no limitation on the colors or patterns available because you're just actually seeing the background, and it works instantaneously. There's no time needed

to change if you just are transparent. Of course, there are difficulties with transparency as well, but one example I might use would be um if you've ever seen pictures of this, there is a butterfly known as the glass wing butterfly that has uh, you know, like all butterflies, it has large, beautiful wings, but most of the surface of its wings is actually transparent, like a like a

pane of glass. It has a sort of orange and black and white outline of the wings, but most of the wings you can just see right through them and they're not even reflective. They don't cause a glare. I was watching a video about this. Actually, in the glass wing butterflies are able to prevent their wings from being too reflective or or or shining back with a glare by having these little tiny nano pillars of wax on the surface of the transparent membranes that sort of break

up light patterns. I think kind of like the way that you might have, uh, you know, cones of foam on the walls of a studio to break up the reflection of sound waves. On this they would break up the reflection of light waves with these tiny little wax spikes all over the wings. Of course you can't see them because they're too small. Instead, it just looks like

clear glass. Yeah, these are weird to see in in the wild because it does look even as they're you're watching them fly around, it looks like, well, something or something has come along and just punch sections of their wing out. Uh, it's just completely translucent. But the wings

wouldn't work, of course, if they just had holes in them. Instead, they actually had to evolve layers of cells in their wings, thin layers of cells that would allow light to pass right through and would prevent the surface of the wings from picking up glare from the sunlight, but also would

still be solid enough to work as wings. Yeah, that they're they're sort of like Wonder Woman's invisible plane, right right, right, But I think it works for the butterfly because the material of wings can be very thin, right, it's a sort of thin. I believe it's made mostly of kitan in this case, you know, kitan and and cells that can allow that to happen. It's gonna be harder to do with, say, like the thick, fleshy body parts of something like a frog. And they're also strategic limitations to

camouflage via transparency, especially on land. Some aquatic animals use transparency for camouflage, and we'll get more into that in a bit when I know there's some examples you wanted to talk about, rob but terrestrial animals run into some different problems because on land, the author's right quote, image distortion maybe more obvious than in water, and that kind of makes sense, right, It might be easier to see the weird way that even a pretty clear thing like

a glass wing, butterflies wing still causes a little bit of distortion in the background. It does. It's not as if there's nothing there. It's just remarkably clear for an actual biological surface. Now, of course, glass frogs are terrestrial animals.

They make use of transparency or translucency, especially pronounced in some species, and it is presumably a camouflage tactic, but as I said earlier, we don't really know for sure, or at least before this paper, it was harder to know, Like is, if it is a camouflage tactic, how exactly does it work and does it does it work at all?

Could that be empirically verified? Uh, and especially given some strange features such as the fact that the that in the ones that are very clear, the really clear part of the skin is usually on the ventral side, the belly side, and that's the part that would be facing down to the surface that they're perched on. More often they tend to have some dorsal pigmentation, so on the back they might have sort of green and yellow color patterns. You can see they're not totally clear on the back.

And so the authors of this paper did a number of different experiments contained within it to to try to figure out what was going on with these frogs. So they like simulated the vision of predators that prey on the frogs in the lab and looked at frogs with differing levels of translucency or opacity to see if it made a difference for those predators. They also tested it just with humans looking at them to see if there were differences in in detection or recognition times based on

how translucent or opaque the frog is. And then they also performed an experiment in the wild with simulated frogs. They like made fake glass frogs out of gelatin uh with with different levels of opacity versus translucency to see if it affected predation. And what these experiments found was that the quote perceived luminants of the frogs was the big thing that really changed, and it changed depending on

the background compared to opaque frogs. So I think one of the really important things to understand here is that the translucency of the glass frog doesn't actually change the color of the frog very much. I mean it's it's basically most of them have some kind of green or green yellow coloration pattern and that pretty much stays the same.

What actually changes is the amount of light that is allowed to pass through the frog, and specifically parts of the frogs, such as the outlines of the toes and the legs, and the transparency of these frogs actually did help them blend in with the background, especially when they're you know, they're on something like a leaf, and it will allow light to pass through their bodies in a manner consistent with the leaf underneath, especially at the edges

where their legs are meeting the surface. And they did find ecologically that this level of transparency did increase survival. So frogs that let more light through their skin got preyed on by birds less. Now coming to I mentioned the legs, they say that the legs made the biggest difference here. They said it was the legs quote which surround the body at rest and create a diffuse transition from background to frog luminants, rather than a sharp, highly

salient edge. So I think that's the important way to think about this. What does the glass frogs translucent skin do. It doesn't make the frog invisible, and it doesn't necessarily change the color of the frog. Instead, what it does is it sort of erases the outline of the frog instead of a sharp line of color change or high contrast between the frog and its background. Instead, there's a gradual soft transition from background to frog because the frog

skin allows that light to pass through. And this is a camouflage strategy they call edge diffusion. The real purpose is to take away your body's outline. Yeah, I mean you see that in various like military camouflage designs as well.

And it always makes me think of have you ever seen these examples of playing cards from World War Two where each plane card has the outline of a different enemy aircraft on it, The idea being that it will sort of while I guess the soldiers are sent around playing cards, they'll also end up boning up on what particular enemy aircraft look like, what their outlines look like

in the sky, so they can identify them. Uh. So you know, it's a it would be kind of like, then, okay, if we have the basic outline of the of the airplane uh in people's minds, well, what can we do to break up that outline so that it's not instantly identifiable? Because whether you're talking about animals or you're talking about uh in the natural environment, or you're talking about humans in a military situation, it like seeing something identifying something

and then comes whatever the action is. And if you can break up that chain of reactions, then you can buy yourself some time. Right, And the the outline is incredibly important for that recognition component. Like rob again, you can look at these pictures I attached near the top of this section here, both of which are of glass frogs perching on a green leaf that's being sort of

brightly lit or lit from behind. And in both cases, actually, no matter which direction the light sources coming from, the soft diffuse edges of the frog really do help it kind of look more just like a kind of spot sun a leaf or something. Yeah, like I In both of these cases, it's the frog is pictured next to a pile of the eggs, and like I say, the frog looks more like a pile of eggs than a frog. It looks more like you know, you look at it, and you're more likely to say, what is that weird

jelly shape? Oh it's a frog, as opposed to instantly I identifying a frog. It just throws you off, even for even just a fraction of a second. Uh. And this is in a case where we know what we're looking at. It's supposed to be a picture of a frog. Yeah, And sometimes a fraction of a second is all you need, maybe if you're trying to avoid the gaze of a bird that's passing by, or a wasp that's passed by, or you're trying to kick a wasp in the face,

that sort of thing. But as I mentioned a minute ago, while the the use of translucency or transparency in animals is uh somewhat rare on land, it's actually more common in the water, and there are some amazing examples in in marine organisms. That's right. Yeah, there are a number of examples that I think line up quite well with with camouflage and uh. And in all cases, I guess

it helps to be kind of small. The smaller you are as an organism, the the easier it's going to be to have some sort of translucency or transparency to your body. Um. That being said, there are some very large jellies, uh, you know, to take up a fair amount of space that of sir or to varying degrees translucent. But this is why the chances of actually seeing something like one of Fritz Leiber's googles, or say a translucent

elephant are are pretty slim. But an internet, yeah, there are a lot of a lot of creatures in the sea that that match up with this. You have things like glass octopi and so forth. Um, but yeah, they're also do some really strange fish in the sea. There are so many strange fish in the see that frankly, not being a strange fish is a bit strange. And one of the stranger fish that you'll likely see is

an image of the barrel i fish Macropinna microstoma. So I think a lot of you've probably seen this image before. And if you were to look up micro Piana microstoma or just look up barrel eye, you'll see the one or two famous images of this fish. It's a fish so strange that you'll likely say, well, where does the fish get off looking so strange? And then hearing you, this fish will gaze you with its tu tubular eyes staring straight through the translucent, fluid filled shield that composes

the upper portion of its head. This is uh, just a bizarre and I think oddly kind of cute looking fish at least. And then, like I said, they're there are a couple of photographs that are that are out there just all over the place. Because this one really tore up the nature blogs years ago, and even I think you're less scientifically inclined boards and and so forth. We're like, what is this? Look at this strange creature.

How can this be? You know? What it reminds me of is I had to look up the name of this because I didn't know what it was called. But the remember those glass balls they would have in like Worlds of Wonder or something with the the electricity and sid. Yeah, it's apparently called a plasma globe or a plasma lamp. Yeah, it looks kind of like a plasma lamp for sure. Yeah.

So it's like a it's like a clear glass ball, and then inside it'll be filled with some kind noble gas, I don't know, neon or something, and then it will have a high voltage electrode in the middle. And I guess, so what when you touch the you touch the glass, it's sort of like tries to jolt out at you. Well, that's what this fish's head looks like that you're just looking in it. I don't know if that's brains or

what it's. It's it looks like plasma. Yeah, this this creature is so to be clear, most of this fish is not translucent or transparent, but the top of the head is and inside you see primarily these two big tubular type globes and these are the creature's eyes. So I'll get back in a second to what this means.

But um, this creature is the the only known member of their genus, but they are part of the barrel eye family or pisto proc today home to the spook fishes as they're called, with that that all have these weird tubular telescoping eyes. Um. Now, these deep sea creatures have eyes like this, so they can uh look, they can lock into a vertical position, but they can also

scan the depths above for possible prey. So so I imagine yourself living kind of deep, but you're you're also concerned with the the lighter regions of the ocean above you because that's where potential food is. So you need to be able to look straight up while yourself remaining in a horizontal position, and so that's what they've evolved

to do. But then they can also direct them forward as well, obviously to aid in such forward facing ventures as say, actually eating the prey or dealing with things that are happening on your level of the ocean. But all these other tubular eyes spook fishes, Uh, they do not have this this strange translucent head situation going on. This is something that we find particularly in the macro penum microstoma. And I was reading about them in a paper.

This was published in the journal Copeia. But it's by authors Robert Robinson and a Rising Bituler, and it's titled macro Penum Microstoma and the Paradox of its Tubular Eyes. So I want to read. I want to read just a quote from this quote. The most striking aspect of these fishes, when first viewed in situ, is the transparent cow like shield that covers the top of the head

and the prominent tubular eyes. Within the shield is a tough, flexible integument that attaches to dorsal and medial scales behind the head and to the broad, transparent subocular bones that protect the eyes. Latterly, this fragile structure is typically lost or collapsed during capture by nets, and it has not been previously described or figured. Beneath the shield is a

fluid filled chamber that surrounds and protects the eyes. Okay, so first of all, one of the things they mentioned, there's something we've discussed regarding deep sea creatures as well. You know, you you bring these up through the depths, stuff employ modes or explodes, etcetera, and you really implodes, I guess gets torn and what you end up with is kind of like the deflated balloon version of the

animal as it would exist in the depths. Yeah, this would be like sometimes people go fishing for deep sea fish and pull them up and it looks like they've got some giant tongue sticking out of their mouth. That's actually like their guts being inverted by the change in pressure because they've got like a swim bladder, and then when that comes up to when they come up the pressure is too low, that inflates and it pops their stomach out. Is really gross. Yeah, So sometimes you'll see

threads where people are like, look at this blobfish. How disgusting? What disgusting things live in the depths, And you almost want to see a Gary Larson far side reversal of that situation where you have the like luminous and deep sea creatures that are all spread out in ballooney and they have dragged like a human body down into the crushing depths. And they're like, look at this thing, look

at this disgusting creature from the surface world. Yeah, or just pulled literally pull your body into the vacuum of space and say like what a what a whimp. But but anyway, this description they give of which I really like it, describing it as a cowl like shield. Like what they're saying here is that there is this this clear like shield on the top of their head. It's filled with fluid, and inside that fluid behind that shield

are its eyes. And so this is wondrous when you start thinking about, well, what does it mean when you have translucency or transparency as an option for uh, for flesh on a being you know, imagined or otherwise well, like to come back to Fritz Lieber's ghouls, it would mean why do you need your eyes to to to be on the outside of your body at all? Why not have more material there between your delicate eyes and the you know, the harmful, scabby outside world. That's an

amazing point. Yes, if you have parts of your body that are as clear as glass, you could put your eyes inside those parts. And yeah, yeah, I mean in a way you could already say that's sort of true. I mean, I guess it's not true because I mean, we have focusing parts that are basically right on the exposed parts of our eyes, the cornea and the lens and all that. But you could say that the light sensing cells in our retina are they're not exposed to

the outside there in the back of the eye. Um. So you could just take that another step further and just say, well, let's add another clear protective layer. Um, except that's just like your skin now outside the eye. Yeah. And of course with fish too, you can also I think there's also a strong argument to being made for like the various like slimy membranes that coat of fish as being an extra level of protection that is generally translucent as well. But oh and you know, just to

mention the Fritz labor cool thing again. Uh. We also when thinking about eyes, we also have to remember that with human eyes, uh, we also have eyelids. Because it's not just about what light does when it enters the eye. We also need to control how much light is entering the eye, something that would be I guess quite difficult

if you if your your eyelids were completely transparent. Yeah. Anyway, back to this theory because this fish is ultimately even more amazing because its head is kind of like a space helmet, you know, with eyes looking out through the substance of this call like shield. And so this leads to the big question, why is it like this like this is this isn't surely isn't a case of camouflage, and it doesn't seem to be a case of like breaking up the overall outline of the organism. So what

is the deal? So the authors here of this paper, they write that the main hypothesis is that the shield is there for protection. It provides protection for these eyes from the tentacles of Nigerians, one of the apparent sources of food for this fish, So we're talking about like stinging jellyfishes and the like. So they're gazing up, they're hoping to catch sight of some sort of swirling jelly

mass of deliciousness. But the thing about that swirling mass of jelly deliciousness is that it also will have tentacles and nematicists in there that can can damage your tissue. All the better than if there's this extra layer of protection between your delicate eyes and all of that. All of those bioweapons, so it's able to rise up and uh and entangle itself and all of that and start eating without damaging its eyes. But so you say this

is just the reigning hypothesis. I guess this is difficult to test because this is like a delicate deep sea organism and it's access Yeah. Yeah, but it seems seems to be the best argument for what's going on here and uh and yeah, and it makes sense. Why else have your your eyes so secluded inside of this this strange space helmet like uh like head cranial feature. It's it's amazing. I love this fish. Yeah, and again these

images are quite captivating. A lot of people were amazed by this because it looking at it, not knowing what you're looking at, it's easy to mistake of some details on the front of the fishes, I mean, for lack of a better word, face thinking those of the eyes. And it has maybe like two globular brains or something, but that the globular things that the things that look like a pair of um of globes, those are the eyes. Wow.

And if you the thing is, if you look up examples of other tubular eyed fish, you can see this a little better. However, this fish is so popular that if you do Google image searches for tubular eyed fish, you're probably gonna mostly just see this guy because he's just really taken over. He's been an Internet sensation steal in the limelight. But macropinna is not the only fish that incorporates transparent or translucent body elements, right right, Uh,

there are a number of other ones. And you know now that you set it up, so I I had an example of just a purely camouflage based translucent fish. But my next example, uh kind of excuse the definition a little bit um, but but does contain some some species and specimens that have a translucent look to them. Uh so, and we're dealing with the crocodile ice fish. These composed an entire family Chennic to Day of fish that are found in the icy waters of the southern

Ocean ant Heatarctica. Now, some of these are again small enough that photographs of the of specimens and species with the right lighting do look partially translucent. But other species in particular specimens certainly don't look crystal like. They just look like some sort of a weird big headed gray fish. However, the most interesting thing about these fish is their blood sometimes described as white blood or translucent blood or transparent blood.

This is because their blood is lacking hemoglobin, and they're the only known vertebrates to lack hemoglobin in their blood as adults. Oh wow, interesting and Joe, if you scan down in the notes here, I included an image here from the study I'm about to site which you get to see red blooded fish blood and then also an example of the the milky white almost translated, I would say,

translucent blood of these crocodile fish. So it's it's not quite androids in the alien franchise level of white blood. It's not like, you know, milk coming out of their bodies. White blood. Yeah, that was milk. Yeah. This reminds me of certain um spirits alcohols that you'll find that have kind of a uh like an opay milky consistency without

being like that white. But any rate, it's pointed out by Siddle and O'Brien in When Bad Things Happen to Good Fish excellent title published in Journal of Experimental Biology in two thousand six. This is a unique trait due to their cold, isolated environment resulting and not only the loss of hemoglobin expression, but sometimes myoglobin expression is well

and to refresh. Hemoglobin is a red protein responsible for transporting oxygen in the blood of vertebrates, and myoglobin is a red protein containing heme, which carries in stores oxygen in muscle cells. Right. Myoglobin is a great example, Like if you ever cut open a piece of meat that you get, you know, the grocery store, that's probably and it's got like some red juice coming out of it. People often call that blood. They think it is blood.

But you know, an animal that's been butchered has usually been drained of its blood. That's gonna be myoglobin. It's this. It's the sort of pinkish fluid within the muscles. Yeah. So without either of these being expressed in the organism, the result is that their blood is white or colorless or transparent, if you will. So the authors here point out a few key details about the environment that these

fish have evolved to thrive in. So, first of all, is really cold here, obviously, uh, And it's it's not only really cold, but it's oxygen rich. Quote, because oxygen solubility and seawater is inversely proportional to temperature. The cold Antarctic seas thus are an exceptionally oxygen rich aquatic habitat all. Right on top of that, it's isolated. Um, so you have circumpolar currents and deep ocean trenches surrounding the continent

of Antarctica, cutting these creatures off from other fauna. And then also the authors state that these fish need to be evolved with very little niche competition due to a mid tertiary through present crash in fish diversity. So they've evolved, yeah, yeah, So they've evolved to do without hemoglobin because of their low metabolic rates in this cold environment, but also due to the high solubility of oxygen in the water at

the low temperatures in this environment. However, since their blood carries less than ten percent of the oxygen carried in red fish blood, they've also evolved other cardi of vascular adaptations, including enormous hearts with cardiac rates that are quote four

to fivefold greater than that of red blooded species. And so yeah, so the authors drive home that this is blood that works really well with creatures that live in a stable cold water environment, and this region stabilized in such a way roughly ten to fourteen million years ago. Allowing ice fish like this to thrive. And again, these are strange looking fish. You look at them, uh that Sometimes they do look extremely translucent. Other times it's just

kind of a weird looking gray, big headed fish. When you know there's a big honking heart in there working extra hard. It looks like a fish that would uh fallen off the garage and hit Ralphie in the eye and yeah, broke his glasses. Uh. Speaking of you know, coming back to fictional accounts, I know that the image of Micropinna, as well as images of some of the

is translucent glass frogs. I think they must have influenced the animators on the series Adventure Time, because I can think of a few different cases where you had some sort of a creature pop up on that show that had some sort of translucent aspect of its anatomy. That reminds me of both of these creatures. If one does an Internet search for Adventure Time Frog Wizard, you'll see

a character named Buffo that I remember showing up. Yeah, okay, so wait, am I looking at the translucent element here? Looks like it's the throat sack right, kind of puffs up the sack and the sack is translucent, right, Buffo has two wizard hats on his head. But yeah, when he puffs up his throat, you see several different little tadpoles in there that are actually the ones that speak, and each of them has a little wizard hat as well. Oh wow, oh this is also this is a different

biological connection. The frogs that keep their they incubate their tadpoles inside their mouths or digestive systems. Yeah, yeah, I feel like for the biological trifecta here, they should also have this wizard frog vomit up its own stomach and scrape it out with its hands and then swallow the stomach. Again. I got into some of this on a monster factor while back about I can't remember its name offhand, but the creature from Supermyo Brothers Too that spits eggs out

of its mouth, Remember that thing? Yeah yeah, But the closest comparison, jolly that I could make between that in the natural world, it takes us to the realm of amphibians and frogs of um incubating their eggs in curious places and in some cases ejecting them. This makes me feel like we got to do the biology of why the princess can float for two seconds? She did. She was good. She was my go to because she could

do that little flying thing. I would generally do her, or I would do Luigi, but I almost never did Mario were Toad? What was Toads deal? Could he throw farther or something? I don't even remember. Toad was just a I to. Didn't work for me, But then again, I definitely didn't beat that game, did not make it that far. I got as far as like, there's some sort of a hydras snake, and that was that was

the limit. There's a lot of pulling up radishes and that one and then pulling up of radishes and throwing a red That was pretty satisfying, I guess, but that was way too hard for me as a kid. I guess. Berdo Burdo was that creature's name. I had, all Right, does that do it for today? I believe it does. We're gonna go and call it on this episode. Though again, there are a number of other translucent creatures we didn't

have time to get into on this episode. So if you have a particular favorite that we didn't cover right in about it, we'd love to discuss it. Maybe we can break it down in a future episode, future listener mail something like that. Also, if you have thoughts on translucent, fleshed beings and various fictional works, I'm sure it's not

just Fritz Leeper. There have to be some other ones that I'm not thinking of, or you know, the people that were influenced by by Fritz Lieber or the people that influence Fritz liber I'm not sure there might be some older examples to draw on, but at any rate, we'd love to hear from you on any and all of that. We remind you that Stuff to Blow Your Mind is primarily a science podcast, with our episodes coming

out on Tuesdays and Thursdays. Those are the core episodes and the Stuff to Blow your Mind podcast feed We usually do listener mail on Mondays. We also do a short form artifact or monster fact on Wednesdays, and on Fridays we do Weird How Cinema. That's our time to set aside most serious concerns and just talk about a strange film. Huge thanks as always to our excellent audio producer Seth Nicholas Johnson. If you would like to get in touch with us with feedback on this episode or

any other. To suggest a topic for the future, or just to say hello, You can email us at contact at stuff to Blow your Mind dot com. Stuff to Blow Your Mind is production of I Heart Radio. For more podcasts for my heart Radio, because the iHeart Radio app, Apple podcast, or wherever you listening to your favorite shows fo