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