Speaker 1: Hello, and welcome to Stuff to Blow Your Mind. My
Speaker 1: name is Joe McCormick, and today we are bringing you
Speaker 1: an episode from the Vault, an older episode of the show.
Speaker 1: This one originally aired May nineteenth, twenty twenty two, and
Speaker 1: it is called Creature with the Crystal Skin, about animals
Speaker 1: that you can see straight through or see inside. I
Speaker 1: hope you enjoy.
Speaker 2: Welcome to Stuff to Blow your Mind, a production of iHeartRadio.
Speaker 3: Hey, welcome to Stuff to Blow your Mind. My name
Speaker 3: is Robert.
Speaker 1: Lamb and I'm Joe McCormick, and today we're going to
Speaker 1: be talking about a biological topic which has fascinated me
Speaker 1: for a while, ever since I was reading about a
Speaker 1: family of frogs that I'm going to come back to
Speaker 1: in a bit. And this is the idea of transparency
Speaker 1: or translucency in animals, animals that have clear or at
Speaker 1: least translucent skin or other body parts.
Speaker 3: Yeah, and just thinking about this topic brought me back
Speaker 3: made me think about some stories that I probably haven't
Speaker 3: read in about twenty years now, but the tales of
Speaker 3: Fritz Lieber, a genre ryder who lived nineteen ten through
Speaker 3: nineteen ninety two. A fun note, he was the son
Speaker 3: of actor Fritz Lieber, so he's technically a junior to
Speaker 3: his senior. Fritz Lieber Senior was in films like nineteen
Speaker 3: thirty three's Phantom of the Opera starring Claude Rains, and
Speaker 3: then Fritz Lieber Junior's son, Justin Lieber, was a philosopher
Speaker 3: and a sci fi author in his own right.
Speaker 1: I think at some point I just popped open his
Speaker 1: Wikipedia page and I saw there was a top line
Speaker 1: reference to him also being, in addition to being like
Speaker 1: a sword and sorcery author and science fiction author, a
Speaker 1: chess expert. And that was one of those things where
Speaker 1: I was like, is that real or is that just
Speaker 1: like something that the author of them, say, elf, or
Speaker 1: someone associated with them kind of snuck in there.
Speaker 3: I don't know. I'm not as as up on the
Speaker 3: full Fritz Lieber biography there, but he wrote a lot
Speaker 3: of stuff, various genre works. Some of his stories were
Speaker 3: were also adapted into I think like a couple of
Speaker 3: episodes of Night Gallery back in the day. But the closest,
Speaker 3: the thing that's closest to my heart, the material that
Speaker 3: I'm familiar with, are these stories he wrote about these
Speaker 3: two characters Fofford and the Gray Mouser. So this is
Speaker 3: your sort of iconic adventuring duo, and he's these stories
Speaker 3: helped make it iconic. You have a pair, a barbarian
Speaker 3: and a rogue and they get into all manner of adventures.
Speaker 3: These were These were very popular stories. I think they
Speaker 3: had an influence on the development of dungeons and dragons.
Speaker 3: And they hold a pretty well too.
Speaker 1: Well. If it's a barbarian in a rogue, that sounds
Speaker 1: like Conan and SUBATAI.
Speaker 3: Yeah, yeah, yeah, very much of that vein. So they're
Speaker 3: great fun. They're always encountering various enemies and magic and
Speaker 3: magical creatures. And in one work in particular, I believe
Speaker 3: this is The Swords of Lankhma from nineteen sixty eight,
Speaker 3: they encounter gules. Now I love goules, as they appear
Speaker 3: in various other works of fiction, these guls are rather different,
Speaker 3: and I think when I first read Fritz Leiber's Gules,
Speaker 3: I was a little I wasn't that into them. I
Speaker 3: was like, ah, this is a little too different from
Speaker 3: what I'm used to. I just want bone chewing pallid humanoids.
Speaker 3: Because he takes the idea in a rather different direction.
Speaker 1: Okay, so your standard gul is just a sort of
Speaker 1: deathly looking humanoid who hangs out in graveyards and eats
Speaker 1: grave flesh, right.
Speaker 3: Right, These gules have translucent anatomy. Essentially, they just look
Speaker 3: like a walking skeleton because all of the soft tissues
Speaker 3: in their bodies are transparent. So the only thing you
Speaker 3: can actually see is the skeleton, unless like the light
Speaker 3: is just right, because you know, it's not true and
Speaker 3: it's not magical invisibility. It's supposed to be translucent tissue
Speaker 3: based invisibility.
Speaker 1: So you would only see the skeleton. In most cases,
Speaker 1: though there is more than the skeleton. They've got some fleshy,
Speaker 1: soft squishy bits, but those just let the light pass
Speaker 1: right through.
Speaker 3: Yeah, everything is see through except for the skeleton. So
Speaker 3: I actually just want to read a little bit from
Speaker 3: the Swords of Lackmar from nineteen sixty eight. After an
Speaker 3: instant shock, Fawford realized that these must be ghoules, whose
Speaker 3: flesh and inner organs he had heard with much skepticism,
Speaker 3: but now no longer were transparent, except when the skin
Speaker 3: became salily or rosalie, translucent on the genital organs or
Speaker 3: on the lops and small breasts of their women. It
Speaker 3: was said also that they ate only flesh human by preference,
Speaker 3: and that it was strange, indeed, to watch the raw
Speaker 3: gobbits they gulped, course down and churn within the bars
Speaker 3: of their ribs, gradually turning to mush and fading from
Speaker 3: sight as their sightless blood assimilated and transformed the food.
Speaker 3: Granting that a mere normal man might ever have the
Speaker 3: opportunity to watch ghules feast without becoming a supply of
Speaker 3: gobbits himself. That is some pros. Yeah, yeah, he was
Speaker 3: a good, good writer. There's a lot of fun and
Speaker 3: whimsy too. So the Ghules in this story, they describe
Speaker 3: themselves as being crystal fleshed, and they see it as
Speaker 3: their sort of sacred responsibility to consume the flesh of say,
Speaker 3: human beings, because our flesh is murkier, you know, it's
Speaker 3: not that's translucent purity. So when they eat it, they
Speaker 3: eat our flesh, it eventually becomes translucent, It becomes crystal
Speaker 3: inside of them. There's a female Ghul that pops up
Speaker 3: in these stories that I believe of Fawford actually ends
Speaker 3: up falling for after a while, and she also has a.
Speaker 1: Great story about ghoul romance.
Speaker 3: Yeah, yeah, gool romance. But there's a bit where she's
Speaker 3: talking about like the differences between between gules and humans,
Speaker 3: and she tells him bones are beautiful, they are made
Speaker 3: to be seen. And there's another part where Fauford is
Speaker 3: asking questions about what's it like to be a ghoul
Speaker 3: and he picks up on a bit of a scientific
Speaker 3: critique that often comes up when discussing things like H. G.
Speaker 3: Wells Invisible Man. He says, well, how can you see
Speaker 3: anything if light passes right through you? He asked her
Speaker 3: if ghules happen to see with the inside of the
Speaker 3: back of their skulls, and she responds, quote, look closely
Speaker 3: into my eyes, no, without getting between them and the fire.
Speaker 3: Can you see a small rainbow in each That's where
Speaker 3: the light is refracted to the seeing part of my brain,
Speaker 3: and a very tiny real image formed there.
Speaker 1: I love alternative visual anatomy. That's great.
Speaker 3: Yeah. I love that he made sure to actually throw
Speaker 3: that in there to address how his gules see anything.
Speaker 3: But anyway, like I said, when I first read of
Speaker 3: these creatures, I was like, oh, this is too different.
Speaker 3: These are not gouls. I can really get behind But now,
Speaker 3: as we're about to jump into the discussion of some
Speaker 3: amazing natural world organisms that have various levels of translucency
Speaker 3: to their bodies, I'm looking back on Fritz Lieber's ghules,
Speaker 3: and I'm like, these are amazing, these ideas of these translucent,
Speaker 3: fleshed beings like jumping into battle with their axes, and
Speaker 3: to everyone on the other side, they just look like
Speaker 3: skeletons because that's the only part that isn't see through.
Speaker 1: That is great. Okay, well, I guess the first example
Speaker 1: of a real animal I want to talk about today
Speaker 1: a group of animals actually known as the glass frogs.
Speaker 1: And a little bit of terminology distinction. I guess we've
Speaker 1: already said these words, but transparency versus translucency. If you're
Speaker 1: not familiar, transparency you can think of as being clear
Speaker 1: like glass, pretty much allowing all light to pass through,
Speaker 1: whereas translucency you can think of, like frosted glass, is
Speaker 1: allowing a lot of light to pass through, but not
Speaker 1: as much as a total clarity.
Speaker 3: You'll find that these are those sometimes used interchangeably, even
Speaker 3: sometimes in scientific papers. Though.
Speaker 1: Yeah, so, the so called glass frogs comprise many different
Speaker 1: species but they all belong to the family Centralinidae, which
Speaker 1: is found in regions throughout Central and South America. These
Speaker 1: are mostly arboreal creatures, meaning they live in trees, often
Speaker 1: in rainforests, and especially near sources of fresh water. So
Speaker 1: if you want to find a glass frog, most of
Speaker 1: the time a good place to look is like on
Speaker 1: leaves overhanging the bank of a jungle stream. But if
Speaker 1: you were to go out looking for one of these creatures,
Speaker 1: you might have a bit of difficulty difficulty finding the frog,
Speaker 1: even if you're looking right at the leaf where it's perched,
Speaker 1: because glass frogs can blend in very well with foliage
Speaker 1: and Rabbi attached a couple of pictures for you to
Speaker 1: look at here of various green and yellow species of
Speaker 1: glass frogs perched on a leaf. It's especially good to
Speaker 1: look at like a leaf that's sort of lit from behind,
Speaker 1: and the frog will be right next to a collection
Speaker 1: of what looked like little semi transparent, semi opaque spherical globules,
Speaker 1: and these are actually the frog's eggs. One of the
Speaker 1: most striking things about the glass frog family is their skin. Now,
Speaker 1: most species of glass frogs appear from above to have
Speaker 1: a kind of moderately translucent skin, especially on some parts
Speaker 1: of their dorsal sides, such as like the toes or
Speaker 1: the legs, and so you can see the blurry specter
Speaker 1: of bones in their toes or in their legs, which
Speaker 1: is very creepy and very cool. This would be like
Speaker 1: crystal ghules. You can actually see the bones through the skin.
Speaker 1: Some species take this even further and have not only
Speaker 1: semi translucent legs or parts of the backs, but nearly
Speaker 1: totally transparent bellies. So this would be the belly the
Speaker 1: ventral side. Again not all species, but with some it
Speaker 1: can be almost as clear as glass, and you can
Speaker 1: look through and see their internal organs in full color,
Speaker 1: including a little tiny beating heart and a big thick
Speaker 1: red artery going down the middle of the inside of
Speaker 1: the stomach, a big coiled white mass of intestines, and
Speaker 1: so forth.
Speaker 3: I mean they remind you of the visible man and
Speaker 3: the visible woman anatomy kits. Yeah, I think we all
Speaker 3: grew up with you know, where you have the plastics
Speaker 3: see through skin and have you put all the little
Speaker 3: organs in there. It's like this frog is meant to
Speaker 3: be an anatomical education tool.
Speaker 1: Now, another feature only tangentially related to their transparence your translucency.
Speaker 1: If you've ever seen the Planet Earth feature on glass frogs,
Speaker 1: it includes at least one species of glass frog that
Speaker 1: shows this amazing egg defense behavior. So with these frogs,
Speaker 1: what will often happen is that there will be a
Speaker 1: clutch of fertilized eggs sticking to the side of a
Speaker 1: leaf that may be hanging above the water, and there
Speaker 1: will be a father frog guarding the eggs. These eggs
Speaker 1: are apparently a favorite food of local carnivorous wasps that
Speaker 1: will kind of zoom in and try to munch on
Speaker 1: them and pull a partially formed tadpole out of the
Speaker 1: egg and take it away to eat it. But the
Speaker 1: frog fathers actually defend their eggs literally by kicking the wasps,
Speaker 1: which is amazing to watch. You should look up this clip.
Speaker 3: Yes I was watching this earlier, as is often the
Speaker 3: case with Planet Earth footage. Very impressive, gorgeous to watch,
Speaker 3: but it also really drives home how much the glass
Speaker 3: frog looks like a clutch of eggs on the back
Speaker 3: of that leaf.
Speaker 1: Yes, they often have marking or coloration patterns on their
Speaker 1: backs that makes the adult male frog look like a
Speaker 1: clutch of eggs itself, so it just kind of blends
Speaker 1: in and then when the wasp gets close, it kicks.
Speaker 1: One of the amazing things is seeing so it's this
Speaker 1: tiny little frog. And a lot of these these frogs
Speaker 1: are so small. They might be just a you know,
Speaker 1: the size of the size of a fingertip, maybe a
Speaker 1: couple of centimeters. I mean, they vary in size with
Speaker 1: different species, but most of them are very small. But
Speaker 1: then when you see that leg suddenly launch out like
Speaker 1: a spring, it's like enormous. It's incredible how far it reaches.
Speaker 1: But to come back to the glass element of the
Speaker 1: glass frog, what is this translucent or in some cases
Speaker 1: nearly transparent skin for why would it be of evolutionary
Speaker 1: benefit to this frog to have parts of its body
Speaker 1: being almost clear? Well, I think for a long time
Speaker 1: it was presumed to have some kind of role in camouflage,
Speaker 1: but we didn't really know for sure. But there was
Speaker 1: a paper published in twenty twenty by James B. Barnett
Speaker 1: at All in Proceedings of the National Academy of Sciences
Speaker 1: called Imperfect Transparency and Camouflage in glass Frogs, And this
Speaker 1: was really interesting. It did some experiments to try to
Speaker 1: look at the translucent skin of a glass frog and
Speaker 1: say what does it actually do in practice? Does it
Speaker 1: work as camouflage and if so how? Now They start
Speaker 1: by giving some background on biological camouflage in general. For example,
Speaker 1: camouflage patterns on animals can help in multiple ways. They
Speaker 1: say they can prevent both detection and recognition, so you
Speaker 1: can imagine those as two slightly different things. Preventing detection
Speaker 1: might mean that a predator doesn't notice you at all,
Speaker 1: like they don't see that you're there, whereas preventing recognition
Speaker 1: might mean that if the predator sees you, it doesn't
Speaker 1: recognize you as what you are, maybe you look like
Speaker 1: something else. And the authors mentioned that there are multiple
Speaker 1: ways camouflage works. It can work by, say, matching a background.
Speaker 1: There are lots of examples of this. But you can
Speaker 1: think about a moth or a butterfly that has patterns
Speaker 1: in coloration on its wings that resemble the patterns and
Speaker 1: coloration of the bark of a treees it lands on
Speaker 1: the tree, and it just kind of blends in. Another
Speaker 1: thing would be mimicking particular background features, trying to recreate
Speaker 1: textures that would exist in the background, and another thing
Speaker 1: would be disrupting or breaking up edges trying to have
Speaker 1: patterns that make it harder to tell where the outline
Speaker 1: of an animal would be. But they raise an interesting question.
Speaker 1: What if you're an animal that lives in a habitat
Speaker 1: where you can't always predict in advance what kind of
Speaker 1: background you will be the foreground of What if you're
Speaker 1: a vulnerable creature that needs camouflage but you live in
Speaker 1: a highly variable environment. Evolution has at least one solution
Speaker 1: to this, which is active color change. So we've talked
Speaker 1: about this on the show before, but think of octopuses
Speaker 1: with their chromatophorre cells that allow them to shift colors
Speaker 1: and blend in with seaweed or rocks or the sandy
Speaker 1: floor of the ocean. There are tons of amazing videos
Speaker 1: of this. You can look up where you wouldn't even
Speaker 1: see it, Like a octopus just lands among some rocks
Speaker 1: or some coral or seaweed or something and it just
Speaker 1: becomes them. It's amazing.
Speaker 3: Yeah, I just almost a year ago I got to
Speaker 3: observe an octopus in the wild in Hawaii, and yeah,
Speaker 3: it got to watch it do this it was amazing,
Speaker 3: like one of these situations where you watch it go
Speaker 3: to some rocks or a bit of coral blend in,
Speaker 3: and since you've been watching it, you can still make
Speaker 3: out where it is. But if you move your eyes
Speaker 3: away from it from just a set for just a
Speaker 3: second and then come back, you can't see it anymore.
Speaker 3: It's still there right in front of you. But the
Speaker 3: camouflage is so perfect it's just quite amazing to behold totally.
Speaker 1: And another classic example one probably everybody's familiar with chameleons.
Speaker 1: They can change colors to match background surfaces in order
Speaker 1: to better blend in. But of course having something like
Speaker 1: chromatophor cells evolving this capability is of course a very
Speaker 1: niche evolutionary specialization, so you need that history feeding into it.
Speaker 1: Is also of course biologically costly, and the authors point
Speaker 1: out that the efficacy of active color change can actually
Speaker 1: be limited by things such as the range of patterns available.
Speaker 1: So an animal that can actively change its markings and
Speaker 1: color patterns can't do that to an infinite degree of flexibility.
Speaker 1: You know, it's still it's going to have surface features
Speaker 1: and colors and like it can change somewhat, but can't
Speaker 1: look like absolutely anything right right. And another thing is
Speaker 1: the speed of change, so it takes a minute. You know,
Speaker 1: you can see this even with octopuses that can change
Speaker 1: very fast, but it still takes a few seconds sometimes.
Speaker 1: So is there any other way to blend in with
Speaker 1: your surroundings? Well, what about transparency. Transparency, of course has
Speaker 1: the ability to create very high fidelity camouflage because you
Speaker 1: can literally see through to the background. It can match
Speaker 1: anything in the background. There's no limitation on the colors
Speaker 1: or patterns available because you're just actually seeing the background,
Speaker 1: and it works instantaneously. There's no time needed to change
Speaker 1: if you just are transparent. Of course, there are difficulties
Speaker 1: with transparency as well, but one example I might use
Speaker 1: would be if you've ever seen pictures of this. There
Speaker 1: is a butterfly known as the glass wing butter fly
Speaker 1: that has you know, like all butterflies, it has large,
Speaker 1: beautiful wings, but most of the surface of its wings
Speaker 1: is actually transparent, like a pane of glass. It has
Speaker 1: a sort of orange and black and white outline of
Speaker 1: the wings, but most of the wings you can just
Speaker 1: see right through them and they're not even reflective. They
Speaker 1: don't cause a glare. I was watching a video about
Speaker 1: this actually, and the glass wing Butterflies are able to
Speaker 1: prevent their wings from being too reflective or shining back
Speaker 1: with a glare by having these little tiny nano pillars
Speaker 1: of wax on the surface of the transparent membranes that
Speaker 1: sort of break up light patterns. I think kind of
Speaker 1: like the way that you might have cones of foam
Speaker 1: on the walls of a studio to break up the
Speaker 1: reflection of sound waves. On this they would break up
Speaker 1: the reflection of light waves with these tiny little wax
Speaker 1: spikes all over the wings. Of course, you can't see
Speaker 1: them because they're too small. Instead, it just looks like
Speaker 1: clear glass.
Speaker 3: Yeah, these are weird to see in the wild because
Speaker 3: it does look even as you're watching them fly around,
Speaker 3: it looks like, well, something or something has come along
Speaker 3: and just punch sections of their wing out. It's just
Speaker 3: completely translucent.
Speaker 1: But the wings wouldn't work, of course, if they just
Speaker 1: had holes in them. Instead, they actually had to evolve
Speaker 1: layers of cells in their wings, thin layers of cells
Speaker 1: that would allow light to pass right through and would
Speaker 1: prevent the surface of the wings from picking up glare
Speaker 1: from the sunlight. But also would still be solid enough
Speaker 1: to work as wings.
Speaker 3: Yeah, they're sort of like Wonder Woman's invisible plane.
Speaker 1: Right, right, right, But I think it works for the
Speaker 1: butterfly because the material of wings can be very thin, right,
Speaker 1: it's a sort of thin. I believe it's made mostly
Speaker 1: of kiten in this case, you know, kiten and cells
Speaker 1: that can allow that to happen. It's going to be
Speaker 1: harder to do with, say, like the thick, fleshy body
Speaker 1: parts of something like a frog. And there are also
Speaker 1: strategic limitations to camouflage via transparency, especially on land. Some
Speaker 1: aquatic animals use transparency for camouflage, and we'll get more
Speaker 1: into that in a bit when I know there's some
Speaker 1: examples you wanted to talk about, rob but terrestrial animals
Speaker 1: run into some different problems because on land, the author's
Speaker 1: write quote, image distortion may be more obvious than in water,
Speaker 1: and that kind of makes sense, right, It might be
Speaker 1: easier to see the weird way that even a pretty
Speaker 1: clear thing like a glass wing butterfly's wing still causes
Speaker 1: a little bit of distortion in the background. It's not
Speaker 1: as if there's nothing there, it's just remarkably clear for
Speaker 1: an actual biological surface. Now, of course, glass frogs are
Speaker 1: terrestrial animals. They make use of transparency or translucency, especially
Speaker 1: pronounced in some species, and it is presumably a camouflage tactic,
Speaker 1: but as I said earlier, we don't really know for sure,
Speaker 1: or at least before this paper it was harder to know.
Speaker 1: Is if it is a camouflage tactic, how exactly does
Speaker 1: it work, and does it work at all? Could that
Speaker 1: be empirically verified? And especially given some strange features such
Speaker 1: as the fact that that in the ones that are
Speaker 1: very clear, the really clear part of the skin is
Speaker 1: usually on the ventral side, the belly side, and that's
Speaker 1: the part that would be facing down to the surface
Speaker 1: that they're perched on. More often they tend to have
Speaker 1: some dorsal pigmentation, so on the back they might have
Speaker 1: sort of green and yellow color patterns. You can see
Speaker 1: they're not totally clear on the back. And so the
Speaker 1: authors of this twenty twenty paper did a number of
Speaker 1: different experiments contained within it to try to figure out
Speaker 1: what was going on with these frogs. So they like
Speaker 1: simulated the vision of predators that prey on the frogs
Speaker 1: in the lab and looked at frogs with differing levels
Speaker 1: of translucency or opacity to see if it made a
Speaker 1: difference for those predators. They also tested it just with
Speaker 1: humans looking at them to see if there were differences
Speaker 1: in detect or recognition times based on how translucent or
Speaker 1: opaque the frog is. And then they also performed an
Speaker 1: experiment in the wild with simulated frogs. They like made
Speaker 1: fake glass frogs out of gelatine with different levels of
Speaker 1: opacity versus translucency to see if it affected predation. And
Speaker 1: what these experiments found was that the quote perceived luminance
Speaker 1: of the frogs was the big thing that really changed,
Speaker 1: and it changed depending on the background compared to opaque frogs.
Speaker 1: So I think one of the really important things to
Speaker 1: understand here is that the translucency of the glass frog
Speaker 1: doesn't actually change the color of the frog very much.
Speaker 1: I mean, it's basically most of them have some kind
Speaker 1: of green or green yellow coloration pattern and that pretty
Speaker 1: much stays the same. What actually changes is the amount
Speaker 1: of light that is allowed to pass through the frog
Speaker 1: and specifically parts of the frogs such as the outlines
Speaker 1: of the toes and the legs, and the transparency of
Speaker 1: these frogs actually did help them blend in with the background,
Speaker 1: especially when they're you know, they're on something like a leaf,
Speaker 1: and it will allow light to pass through their bodies
Speaker 1: in a manner consistent with the leaf underneath, especially at
Speaker 1: the edges where their legs are meeting the surface. And
Speaker 1: they did find ecologically that this level of transparency did
Speaker 1: increase survival. So the frogs that let more light through
Speaker 1: their skin got preyed on by birds less. Now coming
Speaker 1: to I mentioned the legs, They say that the legs
Speaker 1: made the biggest difference here. They said it was the
Speaker 1: legs quote which surround the body at rest and create
Speaker 1: a diffuse transition from background to frog luminance, rather than
Speaker 1: a sharp, highly salient edge. So I think that's the
Speaker 1: important way to think about this. What does the glass
Speaker 1: frog's translucent skin do. It doesn't make frog invisible, and
Speaker 1: it doesn't necessarily change the color of the frog. Instead,
Speaker 1: what it does is it sort of erases the outline
Speaker 1: of the frog instead of a sharp line of color
Speaker 1: change or high contrast between the frog and its background. Instead,
Speaker 1: there's a gradual, soft transition from background to frog because
Speaker 1: the frog's skin allows that light to pass through and
Speaker 1: this is a camouflage strategy they call edge diffusion. The
Speaker 1: real purpose is to take away your body's outline.
Speaker 3: I like that, Yeah, I mean you see that in
Speaker 3: various military camouflage designs as well, And it always makes
Speaker 3: me think of have you ever seen these examples of
Speaker 3: playing cards from World War Two? Where each playing card
Speaker 3: has the outline of a different enemy aircraft on it,
Speaker 3: The idea being that it'll sort of while I guess
Speaker 3: the soldiers are sent around playing cards, they'll also end
Speaker 3: up boning up on what p cular enemy aircraft look like,
Speaker 3: what their outlines look like in the sky, so they
Speaker 3: can identify them. So, you know, it's it would be
Speaker 3: kind of like, then, okay, if we have the basic
Speaker 3: outline of the of the airplane in people's minds, well,
Speaker 3: what can we do to break up that outline so
Speaker 3: that it's not instantly identifiable? Because whether you're talking about
Speaker 3: animals or you're talking about in a natural environment, or
Speaker 3: you're talking about humans in a military situation, it's like
Speaker 3: seeing something identifying something and then comes whatever the action is.
Speaker 3: And if you can break up that chain of reactions,
Speaker 3: then you can buy yourself some time.
Speaker 1: Right, and the outline is incredibly important for that recognition component.
Speaker 1: Like Robigan, you can look at these pictures I attached
Speaker 1: near the top of this section here, both of which
Speaker 1: are of glass frogs perching on a green leaf that's
Speaker 1: being sort of brightly lit or lit from behind. And
Speaker 1: in both cases, actually, no matter which direction the LA
Speaker 1: sources coming from, the soft, diffuse edges of the frog
Speaker 1: really do help it kind of look more just like
Speaker 1: a kind of spot sun a leaf or something.
Speaker 3: Yeah, Like I mean, both of these cases, it's the
Speaker 3: frog is pictured next to a pile of the eggs,
Speaker 3: and like I say, the frog looks more like a
Speaker 3: pile of eggs than a frog. It looks more like
Speaker 3: you know, you look at it, and you're more likely
Speaker 3: to say, what is that weird jelly shape? Oh, it's
Speaker 3: a frog, as opposed to instantly identifying a frog. It
Speaker 3: just throws you off, even for even just a fraction
Speaker 3: of a second. And this is in a case where
Speaker 3: we know what we're looking at. It's supposed to be
Speaker 3: a picture of a frog.
Speaker 1: Yeah, And sometimes a fraction of a second is all
Speaker 1: you need. Maybe if you're trying to avoid the gaze
Speaker 1: of a bird that's passing by, or a wasp that's
Speaker 1: passing by, or.
Speaker 3: Something trying to kick a wasp in the face, that
Speaker 3: sort of thing.
Speaker 1: But as I mentioned a minute ago, while the use
Speaker 1: of translucency or transparency in animals is somewhat rare on land,
Speaker 1: it's actually more common in the water, and there are
Speaker 1: some amazing examples in marine organisms.
Speaker 3: That's right. Yeah, there are a number of examples that
Speaker 3: I think line up quite well with camouflage, and in
Speaker 3: all cases, I guess it helps to be kind of small.
Speaker 3: The smaller you are as an organism, the easier it's
Speaker 3: going to be to have some sort of translucency or
Speaker 3: transparency to your body. That being said, there are some
Speaker 3: very large jellies, you know, they take up a fair
Speaker 3: amount of space that of course are to varying degrees translucent.
Speaker 3: But this is why the chances of actually seeing something
Speaker 3: like one of Fritz Leiber's ghoules, or say a translucent
Speaker 3: elephant are pretty slim. But yeah, there are a lot
Speaker 3: of creatures in the sea that match up with this.
Speaker 3: You have things like glass octopi and so forth. But yeah,
Speaker 3: there are also just some really strange fish in the sea.
Speaker 3: There are so many strange fish in the sea that frankly,
Speaker 3: not being a strange fish is a bit strange. And
Speaker 3: one of the stranger fish that you'll likely see is
Speaker 3: an image of the barrel eye fish Macropinna microstoma. So
Speaker 3: I think a lot of you've probably seen this image before.
Speaker 3: And if you were to look up Macropinna microstoma or
Speaker 3: just look up barrel eye, you'll see the one or
Speaker 3: two famous images of this fish. It's a fish so
Speaker 3: strange that you'll likely say, well, where does the fish
Speaker 3: get off looking so strange? And then hearing you, this
Speaker 3: fish will gaze at you with its two tubular eyes
Speaker 3: staring straight through the translucent, fluid filled shield that composes
Speaker 3: the upper portion of its head. This is just a
Speaker 3: bizarre and I think oddly kind of cute looking fish
Speaker 3: at least, like I say, there are a couple of
Speaker 3: photographs that are out there just all over the place,
Speaker 3: because this one really tore up the nature blogs years ago,
Speaker 3: and even I think you're less scientifically inclined boards and
Speaker 3: so forth, we're like, what is this? Look at the
Speaker 3: strange creature? How can this be?
Speaker 1: You know what it reminds me of, is I had
Speaker 1: to look up the name of this because I didn't
Speaker 1: know what it was called. But the you remember those
Speaker 1: glass balls they would have in like Worlds of Wonder
Speaker 1: or something with the electricity inside. Yeah, it's apparently called
Speaker 1: a plasma globe or a plasma lamp.
Speaker 3: Yeah, it looks kind of like a plasma lamp for sure.
Speaker 1: Yeah. So it's like a it's like a clear glass ball,
Speaker 1: and then inside it'll be filled with some kind of
Speaker 1: noble gas, I don't know, neon or something, and then
Speaker 1: it will have a high voltage electrode in the middle.
Speaker 1: And I guess what when you touch the you touch
Speaker 1: the glass, it sort of like tries to jolt out
Speaker 1: at you.
Speaker 3: Mm hmm.
Speaker 1: Well that's what this fish's head looks like. You're just
Speaker 1: looking in at I don't know if that's brains or
Speaker 1: what it's. It looks like plasma.
Speaker 3: Yeah, this this creature is so to be clear, most
Speaker 3: of this fish is not translucent or transparent, but the
Speaker 3: top of the head is, and inside you see primarily
Speaker 3: these two big tubular type globes, and these are the
Speaker 3: creature's eyes. So I'll get back in a second to
Speaker 3: what this means. But this creature is the only known
Speaker 3: member of their genus, but they are part of the
Speaker 3: barrel eye family Opisto Proctadae, home to the spookfishes as
Speaker 3: they're called with that all have these weird tubular telescoping eyes. Now,
Speaker 3: these deep sea creatures have eyes like this, so they
Speaker 3: can look, they can lock into a vertical position, but
Speaker 3: they can also scan the depths above for possible prey.
Speaker 3: So I imagine yourself living kind of deep, but you're
Speaker 3: also concerned with the lighter regions of the ocean above
Speaker 3: you because that's where potential food is. So you need
Speaker 3: to be able to look straight up while yourself remaining
Speaker 3: in a horizontal position, and so that's what they've evolved
Speaker 3: to do. But then they can also direct them forward
Speaker 3: as well, obviously to aid in such forward facing ventures
Speaker 3: as say, actual eating the prey or dealing with things
Speaker 3: that are happening on your level of the ocean. But
Speaker 3: all these other tubular eyed spookfishes, they do not have
Speaker 3: this strange translucent head situation going on. This is something
Speaker 3: that we find particularly in the macropenum microstoma, and I
Speaker 3: was reading about them in a paper. This was published
Speaker 3: in the journal Coopia it's by authors Robinson and Rizin Bitchlar,
Speaker 3: and it's titled Macropenum Microstoma and the Paradox of its
Speaker 3: Tubular Eyes. So I want to read. I want to
Speaker 3: read just a quote from this quote. The most striking
Speaker 3: aspect of these fishes, when first viewed in situ, is
Speaker 3: the transparent, cowl like shield that covers the top of
Speaker 3: the head and the prominent tubular eyes. Within the shield
Speaker 3: is a tough, flexible integument that attaches to dorsal and
Speaker 3: medial scales behind the head and to the broad, transparent
Speaker 3: subocular bones that protect the eyes. Latterly, this fragile structure
Speaker 3: is typically lost or collapsed during capture by nets, and
Speaker 3: it has not been previously described or figured. Beneath the
Speaker 3: shield is a fluid filled chamber that surrounds and protects
Speaker 3: the eyes. Okay, so first of all, one of the
Speaker 3: things they mentioned, there's something we've discussed regarding deep sea
Speaker 3: creatures as well. You know, you bring these up through
Speaker 3: the depths, stuff implodes or explodes, etc. And neurally implodes,
Speaker 3: I guess, gets torn and what you end up with
Speaker 3: is kind of like the deflated balloon version of the animal,
Speaker 3: as it would exist in the depths.
Speaker 1: Yeah, this be like sometimes people go fishing for deep
Speaker 1: sea fish and pull them up and it looks like
Speaker 1: they've got some giant tongue sticking out of their mouth.
Speaker 1: That's actually like their guts being inverted by the change
Speaker 1: in pressure because they've got like a swim bladder, and
Speaker 1: then when that comes up to when they come up
Speaker 1: the pressure is too low, that inflates and it pops
Speaker 1: their stomach out. Is really gross.
Speaker 3: Yeah, sometimes you'll see threads where people are like, look
Speaker 3: at this blobfish. How disgusting? What disgusting things live in
Speaker 3: the depths, And you almost want to see a Gary
Speaker 3: Larson far side reversal of that situation where you have
Speaker 3: the like luminous and deep sea creatures that are all
Speaker 3: spread out in balloony and they have dragged like a
Speaker 3: human body down into the crushing depths and they're like,
Speaker 3: look at this thing, look at this disgusting creature from
Speaker 3: the surface world.
Speaker 1: Yeah, or just pulled literally pull your body into the
Speaker 1: vacuum of space and say like what a what a whimp?
Speaker 3: But anyway, this description they give, which I really like it,
Speaker 3: describing it as a cowl like shield, like what they're
Speaker 3: saying here is that there is this this clear like
Speaker 3: shield on the top of their head. It's filled with fluid,
Speaker 3: and inside that fluid behind that shield are its eyes.
Speaker 3: And so this is wondrous when you start thinking about, well,
Speaker 3: what does it mean when you have translucent or transparency
Speaker 3: as a option for flesh on a being, you know,
Speaker 3: imagined or otherwise. Well, like to come back to Fritz
Speaker 3: Laber's gules, it would mean, why do you need your
Speaker 3: eyes to be on the outside of your body at all?
Speaker 3: Why not have more material there between your delicate eyes
Speaker 3: and the you know, the harmful, scabby outside world.
Speaker 1: That's an amazing point. Yes, if you have parts of
Speaker 1: your body that are as clear as glass, you could
Speaker 1: put your eyes inside those parts. And yeah, yeah, I
Speaker 1: mean in a way you could already say that's sort
Speaker 1: of true. I mean, I guess it's not true, because
Speaker 1: I mean, we have focusing parts that are basically right
Speaker 1: on the exposed parts of our eyes, the cornea and
Speaker 1: the lens and all that. But you could say that
Speaker 1: the light sensing cells and our retina are they're not
Speaker 1: exposed to the outside, they're in the back of the eye.
Speaker 1: So you could just take that another step further and
Speaker 1: just say, well, let's add another clear protective layer. Except
Speaker 1: that's just like your skin now outside the eye.
Speaker 3: Yeah, with fish too, you can also I think there's
Speaker 3: also strong argument to be made for like the various
Speaker 3: like slimy membranes, that coat of fish as being an
Speaker 3: extra level of protection that is generally translucent as well.
Speaker 3: But oh and you know, just to mention the fritz
Speaker 3: lever Ghul thing again, we also when thinking about eyes,
Speaker 3: we also have to remember that with human eyes we
Speaker 3: also have eye lids. Because it's not just about what
Speaker 3: light does when it enters the eye. We also need
Speaker 3: to control how much light is entering the eye, something
Speaker 3: that would be I guess quite difficult if you if
Speaker 3: your your eyelids were completely transparent. Yeah, anyway, back to
Speaker 3: this fid, because this fish is ultimately even more amazing
Speaker 3: because its head is kind of like a space helmet,
Speaker 3: you know, with eyes looking out through the substance of
Speaker 3: this call like shield. And so this leads to the
Speaker 3: big question, why is it like this like this is
Speaker 3: this isn't It really isn't a case of camouflage, and
Speaker 3: it doesn't seem to be a case of like breaking
Speaker 3: up the overall outline of the organism. So what is
Speaker 3: the deal? So the authors here of this paper, they
Speaker 3: write that the main hypothesis is that the shield is
Speaker 3: there for protection. It provides protection for these eyes from
Speaker 3: the tentacles of Nigerians, one of the apparent sources of
Speaker 3: food for this fish. So we're talking about like stinging
Speaker 3: jellyfishes and the like. So they're gazing up, they're hoping
Speaker 3: to catch sight of some sort of swirling jelly mass
Speaker 3: of deliciousness. But the thing about that swirling mass of
Speaker 3: jelly deliciousness is that it also will have tentacles and
Speaker 3: nematicists in there that can damage your tissue all the
Speaker 3: better than if there's this extra layer of protection between
Speaker 3: your delicate eyes and that all of those bioweapons. So
Speaker 3: it's able to rise up and entangle itself in all
Speaker 3: of that and start eating without damaging its eyes.
Speaker 1: So you say, this is just the raining hypothesis. I
Speaker 1: guess this is difficult to test because this is like
Speaker 1: a delicate deep sea organism and right access.
Speaker 3: Yeah, yeah, but it seems seems to be the best
Speaker 3: argument for what's going on here, And yeah, it makes sense.
Speaker 3: Why else have your eyes so secluded inside of this
Speaker 3: this strange space helmet like head cranial feature. It's amazing.
Speaker 1: I love this fish.
Speaker 3: Yeah, and again these images are quite captivating. A lot
Speaker 3: of people were amazed by this because it looking at it,
Speaker 3: not knowing what you're looking at, it's easy to mistake
Speaker 3: of some details on the front of the fishes, I mean,
Speaker 3: for lack of a better word, face thinking, those are
Speaker 3: the eyes, and it has maybe like two globular brains
Speaker 3: or something, but that the globular things. That the things
Speaker 3: that look like a pair of globes, those are the eyes.
Speaker 1: Wow.
Speaker 3: And if you the thing is, if you look up
Speaker 3: examples of other tubular eyed fish, you can see this
Speaker 3: a little better. However, this fish is so popular that
Speaker 3: if you do Google image searches for tubular eyed fish,
Speaker 3: you're probably gonna mostly just see this guy because he's
Speaker 3: just really taken over. He's been an Internet sensation.
Speaker 1: Steal in the limelight. But Macropinna is not the only
Speaker 1: fish that incorporates transparent or translucent body elements.
Speaker 3: Right right, there are a number of other ones. And
Speaker 3: now that you set it up, so I wish I
Speaker 3: had an example of just a purely camouflaged based translucent fish.
Speaker 3: But my next example kind of exkews the definition a
Speaker 3: little bit, but does contain some species and specimens that
Speaker 3: have a translucent look to them. So we're dealing with
Speaker 3: the crocodile ice fish. These compose an entire family Chennick
Speaker 3: the day of fish that are found in the icy
Speaker 3: waters of the southern Ocean ant Antarctica. Now, some of
Speaker 3: these are again small enough that photographs of specimens and
Speaker 3: species with the right lighting do look partially translucent, but
Speaker 3: other species and particular specimens certainly don't look crystal like.
Speaker 3: They just look like some sort of a weird, big
Speaker 3: headed gray fish. However, the most interesting thing about these
Speaker 3: fish is their blood, sometimes described as white blood or
Speaker 3: translucent blood or transparent blood. This is because their blood
Speaker 3: is lacking hemoglobin, and they're the only known vertebrates to
Speaker 3: lack hemoglobin in their blood as adults.
Speaker 1: Oh wow, interesting.
Speaker 3: And Joe, if you scan down in the notes here,
Speaker 3: I included an image here from the Studiu I'm about
Speaker 3: to site which you get to see red blooded fish blood,
Speaker 3: and then also an example of the milky white, almost
Speaker 3: translated I would say, translucent blood of these crocodile fish,
Speaker 3: So it's not quite androids in the alien franchise level
Speaker 3: of white blood. It's not like milk coming out their bodies.
Speaker 1: That white blood. Yeah, that was milk.
Speaker 3: Yeah. This reminds me of certain spirits alcohols that you'll
Speaker 3: find that have kind of a like an opay milky
Speaker 3: consistency without being like that white. But anyway, it's pointed
Speaker 3: out by Sidel and O'Brien in When Bad Things Happen
Speaker 3: to GoodFish excellent title published in Journal of Experimental Biology
Speaker 3: in two thousand and six. This is a unique trait
Speaker 3: due to their cold, isolated environment, resulting in not only
Speaker 3: the loss of hemoglobin expression, but sometimes myoglobin expression as
Speaker 3: well and to refresh. Hemoglobin is a red protein responsible
Speaker 3: for transporting oxygen in the blood of vertebrates, and myoglobin
Speaker 3: is a red protein containing heme, which carries and stores
Speaker 3: oxygen in muscle cells.
Speaker 1: Right, So myoglobin is a great example. Like if you
Speaker 1: ever cut open a piece of meat that you get
Speaker 1: in the grocery store, that's probably it's got like some
Speaker 1: red juice coming out of it. People often call that blood.
Speaker 1: They think it is blo blood. But you know an
Speaker 1: animal that's been butchered, has usually been drained of its
Speaker 1: blood that's going to be myoglobin, the sort of pinkish
Speaker 1: fluid within the muscles.
Speaker 3: Yeah, So without either of these being expressed and the organism,
Speaker 3: the result is that their blood is white or colorless
Speaker 3: or transparent, if you will. So the authors here point
Speaker 3: out a few key details about the environment that these
Speaker 3: fish have evolved to thrive in. So, first of all,
Speaker 3: is really cold here, obviously, and it's not only really cold,
Speaker 3: but it's oxygen rich. Quote, because oxygen solubility and seawater
Speaker 3: is inversely proportional to temperature. The cold Antarctic seas thus
Speaker 3: are an exceptionally oxygen rich aquatic habitat all. Right on
Speaker 3: top of that, it's isolated, so you have circumpolar currents
Speaker 3: and deep ocean trenches surrounding the continent of Antarctica, cutting
Speaker 3: these creatures off from other fauna. And then also the
Speaker 3: authors state that these fish need to evolve with very
Speaker 3: little niche competition due to a mid tertiary through present
Speaker 3: crash in fish diversity. So they've evolved yeah, yeah, so
Speaker 3: they've evolved to do without hemoglobin because of their low
Speaker 3: metabolic rates in this cold environment. But also due to
Speaker 3: the high solubility of oxygen in the water at the
Speaker 3: low temperatures in this environment. However, since their blood carries
Speaker 3: less than ten percent of the oxygen carried in red
Speaker 3: fish blood, they've also evolved other cardiovascular adaptations, including enormous
Speaker 3: hearts with cardiac rates that are quote four to fivefold
Speaker 3: greater than that of red blooded species. And so yeah,
Speaker 3: so the authors drive home that this is blood that
Speaker 3: works really well with creatures that live in a stable
Speaker 3: cold water environment, and this region stabilized in such a
Speaker 3: way roughly ten to fourteen million years ago, allowing ice
Speaker 3: fish like this to thrive. And again, these are strange
Speaker 3: looking fish. You look at them. Some times they do
Speaker 3: look extremely translucent. Other times it's just kind of a
Speaker 3: weird looking gray, big headed fish when you know there's
Speaker 3: a big honkin heart in there working extra hard.
Speaker 1: Looks like a fish that would have fallen off the
Speaker 1: garage and hit Ralphie in the eye and he ends
Speaker 1: up crying, Yeah, broke his glasses.
Speaker 3: Speaking of you know, coming back to fictional accounts, I
Speaker 3: know that the image of Micropinna, as well as images
Speaker 3: of some of these translucent glass frogs, I think they
Speaker 3: must have influenced the animators on the series Adventure Time,
Speaker 3: because I can think of a few different cases where
Speaker 3: you had some sort of a creature pop up on
Speaker 3: that show that had some sort of translucent aspect of
Speaker 3: its anatomy that remind me of both of these creatures.
Speaker 3: If one does an Internet search for Adventure Time Frog Wizard,
Speaker 3: you'll see a character named Buffo that I remember showing up.
Speaker 1: Yeah, okay, so wait, am I looking at the translucent
Speaker 1: element here? Looks like it's the throat sack?
Speaker 3: Am I?
Speaker 1: Right? Yeah, kind of puffs up the sack and the
Speaker 1: sack is translucent, right.
Speaker 3: Buffo has two wizard hats on his head. But yeah,
Speaker 3: when he puffs up his throat, you see several different
Speaker 3: little tadpoles in there that are actually the ones that speak,
Speaker 3: and each of them has a little wizard hat as well.
Speaker 1: Oh wow, Oh this is also like this is a
Speaker 1: different biological connection. The frogs that keep their they incubate
Speaker 1: their tadpoles inside their mouths or digestive systems.
Speaker 3: Yeah.
Speaker 1: Yeah, I feel like for the biological trifecta here, they
Speaker 1: should also have this wizard frog vomit up its own
Speaker 1: stomach and scrape it out with its hands and then
Speaker 1: swallow the stomach again.
Speaker 3: I got into some of this on a monster fact
Speaker 3: a while back about I can't remember its name off hand,
Speaker 3: but the creature from Super Mario Brothers Too that spits
Speaker 3: eggs out of its mouth.
Speaker 1: Oh I remember that thing.
Speaker 3: Yeah yeah, But the closest comparison, drolly that I could
Speaker 3: make between that and the natural world world, it takes
Speaker 3: us to the realm of amphibians and frogs incubating their
Speaker 3: eggs in curious places and in some cases ejecting them.
Speaker 1: This makes me feel like we got to do the
Speaker 1: biology of why the princess can float for two seconds?
Speaker 1: She did.
Speaker 3: She was good. She was my go to because she
Speaker 3: could do that little flying thing. I would generally do her,
Speaker 3: or I would do Luigi, but I almost never did
Speaker 3: Mario or Toad.
Speaker 1: Toad. What was Toad's deal? Could he throw farther or something?
Speaker 3: I don't even remember. Toad was just Toad. Didn't work
Speaker 3: for me. But then again, oh, I definitely didn't beat
Speaker 3: that game, did not make it ver far. I got
Speaker 3: as far as like, there's some sort of a hydras snake,
Speaker 3: and that was that was the limit.
Speaker 1: There's a lot of pulling up radishes in that one.
Speaker 3: And pulling up of radishes and throwing a red That
Speaker 3: was pretty satisfying, I guess, but that was way too
Speaker 3: hard for me as a kid. I guess Birdo Burdo
Speaker 3: was that creature's name. I had to look at Birdo Burdo.
Speaker 1: All right, does that do it for today?
Speaker 3: I believe it does. We're going to go ahead and
Speaker 3: call it on this episode. Though, again, there are a
Speaker 3: number of other translucent creatures we didn't have time to
Speaker 3: get into on this episode. So if you have a
Speaker 3: particular favorite that we didn't cover, write in about it.
Speaker 3: We'd love to discuss it. Maybe we can break it
Speaker 3: down in a future episode future listener mail something like that. Also,
Speaker 3: if you have thoughts on translucent fleshed beings in various
Speaker 3: fictional works, I'm sure it's not just Fritz Liber. There
Speaker 3: have to be some other ones that I'm not thinking of,
Speaker 3: or you know, the people that were influenced by by
Speaker 3: Fritz Liber or people that influence Fritz Liber. I'm not
Speaker 3: sure there might be some older examples to draw on,
Speaker 3: but at any rate, we'd love to hear from you
Speaker 3: on any and all of that. We remind you that
Speaker 3: Stuff to Blow Your Mind is primarily a science podcast,
Speaker 3: with our episodes coming out on Tuesdays and Thursdays. Those
Speaker 3: are the core episodes and the Stuff to Blow your
Speaker 3: Mind podcast feed. We usually do listener mail on Mondays.
Speaker 3: We also do a short form artifact or monster fact
Speaker 3: on Wednesdays, and on Fridays we do Weird House Cinema.
Speaker 3: That's our time to set aside most serious concerns and
Speaker 3: just talk about a strange film.
Speaker 1: Huge thanks as always to our excellent audio producer Seth
Speaker 1: Nicholas Johnson. If you would like to get in touch
Speaker 1: with us with feedback on this episode or any other,
Speaker 1: to suggest a topic for the future, or just to
Speaker 1: say hello, you can email us at contact at stuff
Speaker 1: to blow your Mind dot com.
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