WEBVTT - From the Vault: Creature with the Crystal Skin 0:00:06.080 --> 0:00:08.039 Hey, you welcome to Stuff to Blow your Mind. My 0:00:08.119 --> 0:00:09.400 name is Robert Lamb. 0:00:09.480 --> 0:00:12.320 And I'm Joe McCormick, and it's Saturday. We're going to 0:00:12.360 --> 0:00:16.360 the vault. This episode originally aired on May nineteenth, twenty 0:00:16.400 --> 0:00:20.000 twenty two, and it was called Creature with the Crystal Skin. 0:00:20.120 --> 0:00:24.040 I think this was about animals with transparent outer layers. 0:00:24.720 --> 0:00:27.320 Yeah, yeah, this one was a lot of fun, so 0:00:27.640 --> 0:00:32.720 I hope you enjoy. 0:00:31.680 --> 0:00:35.479 Welcome to Stuff to Blow your Mind, a production of iHeartRadio. 0:00:41.560 --> 0:00:44.080 Hey, welcome to Stuff to Blow your Mind. My name 0:00:44.120 --> 0:00:44.720 is Robert. 0:00:44.560 --> 0:00:47.600 Lamb and I'm Joe McCormick. And today we're going to 0:00:47.600 --> 0:00:52.440 be talking about a biological topic which has fascinated me 0:00:52.479 --> 0:00:54.240 for a while ever since I was reading about a 0:00:54.240 --> 0:00:56.400 family of frogs that I'm going to come back to 0:00:56.520 --> 0:01:01.120 in a bit. And this is the idea of transparency 0:01:01.240 --> 0:01:06.600 or translucency in animals, animals that have clear or at 0:01:06.680 --> 0:01:10.160 least translucent skin or other body parts. 0:01:10.480 --> 0:01:14.640 Yeah, and just thinking about this topic brought me back 0:01:14.680 --> 0:01:16.520 made me think about some stories that I probably haven't 0:01:16.520 --> 0:01:20.280 read in about twenty years now, but the tales of 0:01:20.400 --> 0:01:24.360 Fritz Lieber, a genre ryder who lived nineteen ten through 0:01:24.440 --> 0:01:27.360 nineteen ninety two. A fun note, he was the son 0:01:27.440 --> 0:01:30.039 of actor Fritz Lieber, so he's technically a junior to 0:01:30.080 --> 0:01:33.199 his senior. Fritz Lieber Senior was in films like nineteen 0:01:33.280 --> 0:01:36.760 thirty three's Phantom of the Opera starring Claude Rains, and 0:01:36.800 --> 0:01:40.600 then Fritz Lieber Junior's son, Justin Lieber, was a philosopher 0:01:40.800 --> 0:01:42.520 and a sci fi author in his own right. 0:01:42.840 --> 0:01:44.720 I think at some point I just popped open his 0:01:44.760 --> 0:01:47.120 Wikipedia page and I saw there was a top line 0:01:47.200 --> 0:01:49.880 reference to him also being, in addition to being like 0:01:50.040 --> 0:01:52.840 a sword and sorcery author and science fiction author, a 0:01:52.960 --> 0:01:55.440 chess expert. And that was one of those things where 0:01:55.440 --> 0:01:57.360 I was like, is that real or is that just 0:01:57.520 --> 0:02:01.120 like something that the author themselves or someone associated with 0:02:01.160 --> 0:02:02.600 them kind of snuck in there. 0:02:02.800 --> 0:02:05.960 I don't know. I'm not as as up on the 0:02:06.400 --> 0:02:10.240 full Fritz Lieber biography there, but he wrote a lot 0:02:10.280 --> 0:02:14.080 of stuff, various genre works. Some of his stories were 0:02:14.120 --> 0:02:16.079 even were also adapted into I think like a couple 0:02:16.120 --> 0:02:18.800 of episodes of Night Gallery back in the day. But 0:02:20.200 --> 0:02:22.560 the closest, the thing that's closest to my heart, the 0:02:22.560 --> 0:02:24.720 material that I'm familiar with are these stories he wrote 0:02:24.800 --> 0:02:29.240 about these two characters, Fofford and the Gray Mouser. So 0:02:29.320 --> 0:02:33.160 this is your sort of iconic adventuring duo, and he's 0:02:33.440 --> 0:02:36.280 these stories helped make it iconic. You have a pair, 0:02:36.400 --> 0:02:39.000 a barbarian and a rogue and they get into all 0:02:39.040 --> 0:02:42.000 manner of adventures. These were These were very popular stories. 0:02:42.160 --> 0:02:44.519 I think they had an influence on the development of 0:02:44.560 --> 0:02:48.120 dungeons and dragons. And they hold a pretty well too well. 0:02:48.120 --> 0:02:50.360 If it's a barbarian in a rogue, that sounds like 0:02:50.720 --> 0:02:52.440 Conan and SUBATAI. 0:02:52.160 --> 0:02:56.679 Yeah, yeah, yeah, very much of that vein. So they're 0:02:56.720 --> 0:03:00.480 great fun. They're always encountering various enemies and mage and 0:03:00.520 --> 0:03:05.480 magical creatures. And in one work in particular, I believe 0:03:05.520 --> 0:03:09.639 this is The Swords of Lankhmer from nineteen sixty eight, 0:03:10.000 --> 0:03:14.680 they encounter gules. Now I love goules as they appear 0:03:14.720 --> 0:03:18.520 in various other works of fiction, these guls are rather different, 0:03:18.880 --> 0:03:22.120 and I think when I first read Fritz Leiber's gules, 0:03:22.720 --> 0:03:25.160 I was a little I wasn't that into them. I 0:03:25.200 --> 0:03:27.600 was like, ah, this is a little too different from 0:03:27.639 --> 0:03:31.200 what I'm used to. I just want bone chewing pallid 0:03:31.320 --> 0:03:35.400 humanoids because he takes the idea in a rather different direction. 0:03:35.720 --> 0:03:38.000 Okay, so your standard gul is just a sort of 0:03:38.120 --> 0:03:41.560 deathly looking humanoid who hangs out in graveyards and eats 0:03:41.640 --> 0:03:43.800 grave flesh, right right. 0:03:43.600 --> 0:03:49.119 These gules have a translucent anatomy. Essentially, they just look 0:03:49.200 --> 0:03:52.640 like a walking skeleton because all of the soft tissues 0:03:52.680 --> 0:03:55.760 in their bodies are transparent. So the only thing you 0:03:55.760 --> 0:03:59.480 can actually see is the skeleton, unless like the light 0:03:59.640 --> 0:04:02.400 is just right, because you know, it's not true and 0:04:02.520 --> 0:04:07.320 it's not magical invisibility. It's supposed to be translucent tissue 0:04:07.360 --> 0:04:09.240 based invisibility. 0:04:08.640 --> 0:04:11.520 So you would only see the skeleton in most cases, 0:04:11.600 --> 0:04:15.360 though there is more than the skeleton. They've got some fleshy, soft, 0:04:15.400 --> 0:04:18.599 squishy bits, but those just let the light pass right through. 0:04:18.880 --> 0:04:22.520 Yeah, everything is see through except for the skeleton. So 0:04:22.560 --> 0:04:24.400 I actually just want to read a little bit from 0:04:24.720 --> 0:04:28.400 the Swords of Lackmar from nineteen sixty eight. After an 0:04:28.400 --> 0:04:32.599 instant shock, Fawford realized that these must be ghoules, whose 0:04:32.640 --> 0:04:35.880 flesh and inner organs he had heard with much skepticism, 0:04:35.960 --> 0:04:39.960 but now no longer were transparent, except when the skin 0:04:40.080 --> 0:04:45.040 became salily or Rosalie translucent on the genital organs or 0:04:45.080 --> 0:04:48.560 on the lops and small breasts of their women. It 0:04:48.640 --> 0:04:52.440 was said also that they ate only flesh human by preference, 0:04:52.839 --> 0:04:55.320 and that it was strange, indeed, to watch the raw 0:04:55.440 --> 0:04:58.839 gobbits they gulped, course down and churn within the bars 0:04:58.880 --> 0:05:02.479 of their ribs, gradually turning to mush and fading from 0:05:02.560 --> 0:05:06.560 sight as their sightless blood assimilated and transformed the food. 0:05:07.040 --> 0:05:09.800 Granting that a mere normal man might ever have the 0:05:09.839 --> 0:05:13.960 opportunity to watch ghules feast without becoming a supply of 0:05:14.040 --> 0:05:15.200 gobbits himself. 0:05:15.600 --> 0:05:16.480 That is some pros. 0:05:16.880 --> 0:05:19.839 Yeah, yeah, he was a good, good writer. There's a 0:05:19.839 --> 0:05:23.720 lot of fun and whimsy too. So the Ghules in 0:05:23.760 --> 0:05:27.760 this story, they describe themselves as being crystal fleshed, and 0:05:28.960 --> 0:05:31.520 they see it as their sort of sacred responsibility to 0:05:31.600 --> 0:05:35.960 consume the flesh of say, human beings, because our flesh 0:05:35.520 --> 0:05:41.640 is murkier, you know, it's not that's translucent purity. So 0:05:41.680 --> 0:05:45.000 when they eat it, they eat our flesh, it eventually 0:05:45.040 --> 0:05:49.640 becomes translucent, It becomes crystal inside of them. There's a 0:05:49.640 --> 0:05:52.160 female Ghul that pops up in these stories that I 0:05:52.240 --> 0:05:56.279 believe of Fawford actually ends up falling for after a while. 0:05:56.640 --> 0:06:00.279 And she also has a great story about ghoul romance. Yeah, yeah, 0:06:00.320 --> 0:06:05.320 gool romance. But there's a bit where she's talking about 0:06:05.360 --> 0:06:09.039 like the differences between between ghules and humans, and she 0:06:09.200 --> 0:06:11.960 tells him bones are beautiful, they are made to be seen. 0:06:13.240 --> 0:06:17.640 And there's another part where Fauford is asking questions about 0:06:17.680 --> 0:06:20.000 what's it like to be a ghoul and he picks 0:06:20.080 --> 0:06:24.000 up on a bit of a scientific critique that often 0:06:24.040 --> 0:06:27.239 comes up when discussing things like H. G. Wells Invisible Man. 0:06:27.680 --> 0:06:30.760 He says, well, how can you see anything if light 0:06:31.040 --> 0:06:34.240 passes right through you? He asked her if ghules happen 0:06:34.320 --> 0:06:36.599 to see with the inside of the back of their skulls, 0:06:36.960 --> 0:06:40.479 and she responds, quote, look closely into my eyes, no, 0:06:40.680 --> 0:06:43.520 without getting between them and the fire. Can you see 0:06:43.520 --> 0:06:46.760 a small rainbow in each That's where the light is 0:06:46.880 --> 0:06:49.760 refracted to the seeing part of my brain, and a 0:06:49.880 --> 0:06:52.000 very tiny real image formed there. 0:06:52.320 --> 0:06:54.359 I love alternative visual anatomy. 0:06:54.480 --> 0:06:54.920 That's great. 0:06:55.000 --> 0:06:59.520 Yeah, I love that he made sure to actually throw 0:06:59.560 --> 0:07:02.800 that in there to address how his gules see anything. 0:07:02.839 --> 0:07:04.839 But anyway, like I said, when I first read of 0:07:04.880 --> 0:07:07.719 these creatures, I was like, oh, this is too different. 0:07:08.560 --> 0:07:10.560 These are not gouls I can really get behind. But now, 0:07:10.600 --> 0:07:13.360 as we're about to jump into the discussion of some 0:07:13.760 --> 0:07:18.080 amazing natural world organisms that have various levels of translucency 0:07:18.120 --> 0:07:21.160 to their bodies, I'm looking back on Fritz Lieber's ghules 0:07:21.200 --> 0:07:24.680 and I'm like, these are amazing. These ideas of these translucent, 0:07:24.800 --> 0:07:28.440 fleshed beings like jumping into battle with their axes, and 0:07:28.480 --> 0:07:30.880 to everyone on the other side, they just look like 0:07:31.200 --> 0:07:35.120 skeletons because that's the only part that isn't see through. 0:07:35.480 --> 0:07:36.160 That is great. 0:07:36.600 --> 0:07:39.480 Okay, well, I guess the first example of a real 0:07:39.560 --> 0:07:42.640 animal I want to talk about today a group of 0:07:42.680 --> 0:07:46.960 animals actually known as the glass frogs. And a little 0:07:47.000 --> 0:07:50.200 bit of terminology distinction. I guess we've already said these words. 0:07:50.200 --> 0:07:56.160 But transparency versus translucency if you're not familiar, transparency you 0:07:56.160 --> 0:07:58.840 can think of as being clear like glass, pretty much 0:07:58.840 --> 0:08:03.560 allowing all light to pass through, whereas translucency you can 0:08:03.600 --> 0:08:06.520 think of like frosted glass, is allowing a lot of 0:08:06.600 --> 0:08:09.120 light to pass through, but not as much as a 0:08:09.160 --> 0:08:10.000 total clarity. 0:08:10.320 --> 0:08:13.480 You'll find that these are those sometimes used interchangeably, even 0:08:13.640 --> 0:08:15.440 sometimes in scientific papers. 0:08:15.120 --> 0:08:16.440 Though, yeah. 0:08:16.440 --> 0:08:16.560 So. 0:08:16.840 --> 0:08:20.920 The so called glass frogs comprise many different species, but 0:08:20.960 --> 0:08:24.920 they all belong to the family Centralinidae, which is found 0:08:24.920 --> 0:08:28.520 in regions throughout Central and South America. These are mostly 0:08:28.720 --> 0:08:33.160 arboreal creatures, meaning they live in trees, often in rainforests, 0:08:33.360 --> 0:08:37.120 and especially near sources of fresh water. So if you 0:08:37.160 --> 0:08:40.240 want to find a glass frog, most of the time 0:08:40.280 --> 0:08:43.920 a good place to look is like on leaves overhanging 0:08:44.040 --> 0:08:47.600 the bank of a jungle stream. But if you were 0:08:47.640 --> 0:08:50.040 to go out looking for one of these creatures, you 0:08:50.120 --> 0:08:53.680 might have a bit of difficulty difficulty finding the frog, 0:08:53.920 --> 0:08:56.760 even if you're looking right at the leaf where it's perched, 0:08:57.400 --> 0:09:01.640 because glass frogs can blend in very well with foliage 0:09:02.000 --> 0:09:04.120 and Rabbi attached a couple of pictures for you to 0:09:04.160 --> 0:09:07.680 look at here of various green and yellow species of 0:09:07.760 --> 0:09:11.240 glass frogs perched on a leaf. It's especially good to 0:09:11.240 --> 0:09:13.840 look at like a leaf that's sort of lit from behind, 0:09:14.440 --> 0:09:17.400 and the frog will be right next to a collection 0:09:17.760 --> 0:09:23.400 of what looked like little semi transparent, semi opaque spherical globules, 0:09:23.480 --> 0:09:26.880 and these are actually the frog's eggs. One of the 0:09:26.880 --> 0:09:31.440 most striking things about the glass frog family is their skin. Now, 0:09:31.480 --> 0:09:35.440 most species of glass frogs appear from above to have 0:09:35.559 --> 0:09:41.800 a kind of moderately translucent skin, especially on some parts 0:09:42.040 --> 0:09:45.680 of their dorsal sides, such as like the toes or 0:09:45.720 --> 0:09:49.120 the legs, and so you can see the blurry specter 0:09:49.280 --> 0:09:52.400 of bones in their toes or in their legs, which 0:09:52.440 --> 0:09:55.640 is very creepy and very cool. This would be like 0:09:55.760 --> 0:09:59.560 crystal ghules. You can actually see the bones through the skin. 0:10:00.400 --> 0:10:03.400 Some species take this even further and have not only 0:10:03.760 --> 0:10:07.920 semi translucent legs or parts of the backs, but nearly 0:10:08.240 --> 0:10:11.679 totally transparent bellies. So this would be the belly the 0:10:11.760 --> 0:10:15.240 ventral side. Again not all species, but with some it 0:10:15.280 --> 0:10:18.000 can be almost as clear as glass, and you can 0:10:18.080 --> 0:10:22.480 look through and see their internal organs in full color, 0:10:22.559 --> 0:10:26.079 including a little tiny beating heart and a big thick 0:10:26.160 --> 0:10:30.079 red artery going down the middle of the inside of 0:10:30.120 --> 0:10:33.920 the stomach, a big coiled white mass of intestines, and 0:10:33.960 --> 0:10:34.520 so forth. 0:10:34.880 --> 0:10:38.440 I mean they remind you of the visible man and 0:10:38.480 --> 0:10:42.240 the visible woman anatomy kits. Yeah, yeah, I think we 0:10:42.559 --> 0:10:44.679 all grew up with you know, where you have the 0:10:45.120 --> 0:10:47.640 plastics see through skin, and you have you put all 0:10:47.679 --> 0:10:50.480 the little organs in there it's like this frog is 0:10:50.520 --> 0:10:53.880 meant to be an anatomical education tool. 0:10:54.200 --> 0:10:59.720 Now another feature only tangentially related to their transparency here 0:10:59.760 --> 0:11:03.200 trans lucency. If you've ever seen the Planet Earth feature 0:11:03.240 --> 0:11:06.280 on glass frogs, it includes at least one species of 0:11:06.320 --> 0:11:11.160 glass frog that shows this amazing egg defense behavior. So 0:11:11.280 --> 0:11:13.480 with these frogs, what will often happen is that there 0:11:13.480 --> 0:11:17.760 will be a clutch of fertilized eggs sticking to the 0:11:17.800 --> 0:11:20.360 side of a leaf that may be hanging above the water, 0:11:21.200 --> 0:11:24.880 and there will be a father frog guarding the eggs. 0:11:25.440 --> 0:11:29.959 These eggs are apparently a favorite food of local carnivorous 0:11:30.080 --> 0:11:32.440 wasps that will kind of zoom in and try to 0:11:33.040 --> 0:11:36.800 munch on them and pull a partially formed tadpole out 0:11:36.800 --> 0:11:38.880 of the egg and take it away to eat it. 0:11:39.480 --> 0:11:44.560 But the frog fathers actually defend their eggs literally by 0:11:44.760 --> 0:11:48.400 kicking the wasps, which is amazing to watch. You should 0:11:48.440 --> 0:11:49.280 look up this clip. 0:11:49.600 --> 0:11:52.440 Yes, I was watching this earlier, as is often the 0:11:52.480 --> 0:11:56.800 case with Planet Earth footage. Very impressive, gorgeous to watch, 0:11:56.800 --> 0:12:01.320 but it also really drives home how much the glass 0:12:01.360 --> 0:12:04.040 frog looks like a clutch of eggs on the back 0:12:04.120 --> 0:12:05.000 of that leaf. 0:12:05.320 --> 0:12:08.439 Yes, they often have marking or coloration patterns on their backs. 0:12:08.440 --> 0:12:12.200 That makes the adult male frog look like a clutch 0:12:12.240 --> 0:12:14.760 of eggs itself. So it just kind of blends in 0:12:15.280 --> 0:12:19.040 and then when the wasp gets close, it kicks. One 0:12:19.080 --> 0:12:21.160 of the amazing things is seeing. So it's this tiny 0:12:21.240 --> 0:12:23.719 little frog. And a lot of these these frogs are 0:12:23.760 --> 0:12:25.920 so small. They might be just a you know, the 0:12:25.960 --> 0:12:28.920 size of the size of a fingertip, maybe a couple 0:12:28.920 --> 0:12:32.200 of centimeters. I mean, they vary in size with different species, 0:12:32.240 --> 0:12:34.839 but most of them are very small. But then when 0:12:34.880 --> 0:12:38.320 you see that leg suddenly launch out like a spring, 0:12:39.559 --> 0:12:43.920 it's like enormous. It's incredible how far it reaches. But 0:12:44.160 --> 0:12:46.760 to come back to the glass element of the glass frog, 0:12:47.240 --> 0:12:52.040 what is this translucent or in some cases nearly transparent 0:12:52.160 --> 0:12:56.440 skin for why would it be of evolutionary benefit to 0:12:56.480 --> 0:13:01.199 this frog to have parts of its body being almost clear? Well, 0:13:01.240 --> 0:13:04.120 I think for a long time it was presumed to 0:13:04.200 --> 0:13:08.040 have some kind of role in camouflage, but we didn't 0:13:08.080 --> 0:13:11.400 really know for sure. But there was a paper published 0:13:11.400 --> 0:13:14.400 in twenty twenty by James B. Barnett at All in 0:13:15.040 --> 0:13:19.440 Proceedings of the National Academy of Sciences called imperfect transparency 0:13:19.480 --> 0:13:24.400 and camouflage in glass frogs, And this was really interesting. 0:13:24.640 --> 0:13:27.600 It did some experiments to try to look at the 0:13:27.840 --> 0:13:31.240 translucent skin of a glass frog and say what does 0:13:31.280 --> 0:13:35.640 it actually do in practice? Does it work as camouflage 0:13:35.679 --> 0:13:38.400 and if so how? Now They start by giving some 0:13:38.480 --> 0:13:43.720 background on biological camouflage in general. For example, camouflage patterns 0:13:43.720 --> 0:13:46.800 on animals can help in multiple ways. They say they 0:13:46.840 --> 0:13:50.360 can prevent both detection and recognition, so you can imagine 0:13:50.360 --> 0:13:54.000 those as two slightly different things. Preventing detection might mean 0:13:54.080 --> 0:13:56.720 that a predator doesn't notice you at all, like they 0:13:56.720 --> 0:14:00.960 don't see that you're there, whereas preventing recognition might mean 0:14:01.000 --> 0:14:04.360 that if the predator sees you, it doesn't recognize you 0:14:04.520 --> 0:14:07.440 as what you are, maybe you look like something else. 0:14:08.000 --> 0:14:11.160 And the authors mentioned that there are multiple ways camouflage works. 0:14:11.200 --> 0:14:14.000 It can work by say, matching a background. There are 0:14:14.040 --> 0:14:15.920 lots of examples of this. But you can think about 0:14:15.920 --> 0:14:19.680 a moth or a butterfly that has patterns in coloration 0:14:19.800 --> 0:14:23.280 on its wings that resemble the patterns and coloration of 0:14:23.280 --> 0:14:25.320 the bark of a trees. It lands on the tree 0:14:25.360 --> 0:14:27.720 and it just kind of blends in another thing, would 0:14:27.760 --> 0:14:34.040 be mimicking particular background features, trying to recreate textures that 0:14:34.120 --> 0:14:36.920 would exist in the background. And another thing would be 0:14:37.360 --> 0:14:41.920 disrupting or breaking up edges, trying to have patterns that 0:14:42.000 --> 0:14:44.520 make it harder to tell where the outline of an 0:14:44.520 --> 0:14:47.920 animal would be. But they raise an interesting question. What 0:14:48.000 --> 0:14:50.120 if you're an animal that lives in a habitat where 0:14:50.120 --> 0:14:54.280 you can't always predict in advance what kind of background 0:14:54.440 --> 0:14:57.640 you will be the foreground of What if you're a 0:14:57.680 --> 0:15:01.160 vulnerable creature that needs camouflage but you live in a 0:15:01.280 --> 0:15:05.960 highly variable environment. Evolution has at least one solution to this, 0:15:06.080 --> 0:15:10.600 which is active color change. So we've talked about this 0:15:10.640 --> 0:15:13.040 on the show before, but think of octopuses with their 0:15:13.120 --> 0:15:17.160 chromatophor cells that allow them to shift colors and blend 0:15:17.200 --> 0:15:20.480 in with seaweed or rocks or the sandy floor of 0:15:20.520 --> 0:15:24.440 the ocean. There are tons of amazing videos of this. 0:15:24.560 --> 0:15:27.520 You can look up where you wouldn't even see it, 0:15:27.600 --> 0:15:30.440 Like a octopus just lands among some rocks or some 0:15:30.520 --> 0:15:33.880 coral or seaweed or something and it just becomes them. 0:15:34.000 --> 0:15:34.680 It's amazing. 0:15:35.280 --> 0:15:38.440 Yeah, I just almost a year ago I got to 0:15:38.480 --> 0:15:43.160 observe an octopus in the wild in Hawaii, and yeah, 0:15:43.200 --> 0:15:46.040 it got to watch it do this. It was amazing, 0:15:46.200 --> 0:15:48.200 Like one of these situations where you watch it go 0:15:48.320 --> 0:15:51.480 to some rocks or a bit of coral blend in, 0:15:51.920 --> 0:15:54.320 and since you've been watching it, you can still make 0:15:54.360 --> 0:15:57.040 out where it is. But if you move your eyes 0:15:57.080 --> 0:15:58.760 away from it from just a set for just a 0:15:58.800 --> 0:16:03.080 second and then come back, you can't see it anymore. 0:16:03.120 --> 0:16:04.640 It's still there right in front of you. But the 0:16:04.680 --> 0:16:09.520 camouflage is so perfect it's just quite amazing to behold totally. 0:16:09.600 --> 0:16:13.360 And another classic example one probably everybody's familiar with chameleons. 0:16:13.440 --> 0:16:18.280 They can change colors to match background surfaces in order 0:16:18.280 --> 0:16:21.640 to better blend in. But of course having something like 0:16:21.720 --> 0:16:26.080 chromatophor cells evolving this capability is of course a very 0:16:26.560 --> 0:16:30.720 niche evolutionary specialization, so you need that history feeding into it. 0:16:30.760 --> 0:16:35.240 Is also, of course biologically costly, and the authors point 0:16:35.240 --> 0:16:39.360 out that the efficacy of active color change can actually 0:16:39.440 --> 0:16:44.400 be limited by things such as the range of patterns available. 0:16:44.520 --> 0:16:48.600 So an animal that can actively change its markings and 0:16:48.680 --> 0:16:52.920 color patterns can't do that to an infinite degree of flexibility. 0:16:53.000 --> 0:16:56.200 You know, it's still it's going to have surface features 0:16:56.240 --> 0:16:59.640 and colors and like. It can change somewhat, but it 0:16:59.640 --> 0:17:04.080 can't look like absolutely anything right right. And another thing 0:17:04.200 --> 0:17:07.000 is the speed of change, so it takes a minute. 0:17:07.080 --> 0:17:09.119 You know, you can see this even with octopuses that 0:17:09.200 --> 0:17:12.720 can change very fast, but it still takes a few 0:17:12.760 --> 0:17:22.439 seconds sometimes. So is there any other way to blend 0:17:22.480 --> 0:17:27.520 in with your surroundings? Well, what about transparency. Transparency, of 0:17:27.560 --> 0:17:31.600 course has the ability to create very high fidelity camouflage 0:17:31.640 --> 0:17:35.399 because you can literally see through to the background. It 0:17:35.480 --> 0:17:38.520 can match anything in the background. There's no limitation on 0:17:38.560 --> 0:17:42.080 the colors or patterns available because you're just actually seeing 0:17:42.119 --> 0:17:46.480 the background, and it works instantaneously. There's no time needed 0:17:46.520 --> 0:17:49.959 to change if you just are transparent. Of course, there 0:17:49.960 --> 0:17:53.600 are difficulties with transparency as well, but one example I 0:17:53.680 --> 0:17:56.600 might use would be if you've ever seen pictures of this. 0:17:56.680 --> 0:17:59.840 There is a butterfly known as the glass wing butterfly 0:18:00.680 --> 0:18:03.880 that has you know, like all butterflies, it has large, 0:18:03.920 --> 0:18:07.000 beautiful wings, but most of the surface of its wings 0:18:07.480 --> 0:18:10.520 is actually transparent, like a pane of glass. It has 0:18:10.560 --> 0:18:13.199 a sort of orange and black and white outline of 0:18:13.240 --> 0:18:16.000 the wings, but most of the wings you can just 0:18:16.040 --> 0:18:18.840 see right through them, and they're not even reflective. They 0:18:18.840 --> 0:18:22.320 don't cause a glare. I was watching a video about 0:18:22.320 --> 0:18:25.080 this actually, and the glass wing butterflies are able to 0:18:25.200 --> 0:18:29.680 prevent their wings from being too reflective or shining back 0:18:29.720 --> 0:18:34.240 with a glare by having these little tiny nano pillars 0:18:34.280 --> 0:18:38.520 of wax on the surface of the transparent membranes that 0:18:38.640 --> 0:18:41.439 sort of break up light patterns. I think kind of 0:18:41.520 --> 0:18:44.639 like the way that you might have cones of foam 0:18:44.680 --> 0:18:46.639 on the walls of a studio to break up the 0:18:46.680 --> 0:18:49.199 reflection of sound waves. On this they would break up 0:18:49.200 --> 0:18:52.280 the reflection of light waves with these tiny little wax 0:18:52.359 --> 0:18:54.440 spikes all over the wings. Of course, you can't see 0:18:54.440 --> 0:18:56.960 them because they're too small. Instead, it just looks like 0:18:57.040 --> 0:18:57.760 clear glass. 0:18:58.480 --> 0:19:01.480 Yeah, these are weird to see in the wild because 0:19:01.480 --> 0:19:03.840 it does look even as you're watching them fly around, 0:19:04.160 --> 0:19:06.560 it looks like, well, something or something has come along 0:19:06.600 --> 0:19:09.480 and just punch sections of their wing out. It's just 0:19:09.840 --> 0:19:10.960 completely translucent. 0:19:11.200 --> 0:19:13.040 But the wings wouldn't work, of course, if they just 0:19:13.080 --> 0:19:15.680 had holes in them. Instead, they actually had to evolve 0:19:15.880 --> 0:19:18.639 layers of cells in their wings, thin layers of cells 0:19:18.720 --> 0:19:21.640 that would allow light to pass right through and would 0:19:21.720 --> 0:19:24.639 prevent the surface of the wings from picking up glare 0:19:24.720 --> 0:19:28.000 from the sunlight, but also would still be solid enough 0:19:28.040 --> 0:19:29.240 to work as wings. 0:19:29.800 --> 0:19:33.680 Yeah, they're sort of like Wonder Woman's invisible plane. 0:19:33.440 --> 0:19:37.080 Right, right, right, But I think it works for the 0:19:37.480 --> 0:19:42.240 butterfly because the material of wings can be very thin, right, 0:19:42.600 --> 0:19:45.480 it's a sort of thin. I believe it's made mostly 0:19:45.520 --> 0:19:48.879 of kiten in this case, you know, kitan and cells 0:19:48.880 --> 0:19:51.200 that can allow that to happen. It's going to be 0:19:51.240 --> 0:19:54.359 harder to do with, say, like the thick, fleshy body 0:19:54.440 --> 0:19:58.160 parts of something like a frog. And there are also 0:19:58.200 --> 0:20:03.960 strategic limitations to camouflage via transparency, especially on land. Some 0:20:04.080 --> 0:20:07.640 aquatic animals use transparency for camouflage, and we'll get more 0:20:07.680 --> 0:20:09.520 into that in a bit when I know there's some 0:20:09.560 --> 0:20:13.240 examples you wanted to talk about, rob but terrestrial animals 0:20:13.320 --> 0:20:17.160 run into some different problems because on land, the author's 0:20:17.200 --> 0:20:21.680 write quote, image distortion may be more obvious than in water, 0:20:21.840 --> 0:20:23.639 and that kind of makes sense, right, It might be 0:20:23.680 --> 0:20:27.440 easier to see the weird way that even a pretty 0:20:27.560 --> 0:20:31.360 clear thing like a glass wing butterfly's wing still causes 0:20:31.400 --> 0:20:34.159 a little bit of distortion in the background. It's not 0:20:34.280 --> 0:20:37.800 as if there's nothing there. It's just remarkably clear for 0:20:37.960 --> 0:20:42.480 an actual biological surface. Now, of course, glass frogs are 0:20:42.560 --> 0:20:47.040 terrestrial animals. They make use of transparency or translucency, especially 0:20:47.040 --> 0:20:51.680 pronounced in some species, and it is presumably a camouflage tactic, 0:20:51.760 --> 0:20:54.600 but as I said earlier, we don't really know for sure, 0:20:54.720 --> 0:20:56.919 or at least before this paper it was harder to know. 0:20:57.440 --> 0:21:01.000 Is if it is a camouflage tactic, how exactly does 0:21:01.040 --> 0:21:03.040 it work, and does it. 0:21:03.000 --> 0:21:03.520 Work at all? 0:21:03.600 --> 0:21:08.400 Could that be empirically verified, and especially given some strange 0:21:08.440 --> 0:21:11.439 features such as the fact that in the ones that 0:21:11.480 --> 0:21:14.640 are very clear, the really clear part of the skin 0:21:14.720 --> 0:21:18.400 is usually on the ventral side, the belly side, and 0:21:18.560 --> 0:21:21.119 that's the part that would be facing down to the 0:21:21.160 --> 0:21:24.359 surface that they're perched on. More often they tend to 0:21:24.359 --> 0:21:27.280 have some dorsal pigmentation, so on the back they might 0:21:27.320 --> 0:21:29.879 have sort of green and yellow color patterns. You can 0:21:29.920 --> 0:21:32.480 see they're not totally clear on the back. And so 0:21:32.640 --> 0:21:35.120 the authors of this twenty twenty paper did a number 0:21:35.160 --> 0:21:38.280 of different experiments contained within it to try to figure 0:21:38.280 --> 0:21:41.400 out what was going on with these frogs. So they 0:21:40.720 --> 0:21:44.840 like simulated the vision of predators that prey on the 0:21:44.880 --> 0:21:48.440 frogs in the lab and looked at frogs with differing 0:21:48.560 --> 0:21:52.480 levels of translucency or opacity to see if it made 0:21:52.520 --> 0:21:55.760 a difference for those predators. They also tested it just 0:21:55.800 --> 0:21:58.359 with humans looking at them to see if there were 0:21:58.359 --> 0:22:04.400 differences in detection recognition times based on how translucent or 0:22:04.440 --> 0:22:07.959 opaque the frog is. And then they also performed an 0:22:08.000 --> 0:22:11.919 experiment in the wild with simulated frogs. They like made 0:22:12.160 --> 0:22:17.320 fake glass frogs out of gelatine with different levels of 0:22:17.440 --> 0:22:22.480 opacity versus translucency to see if it affected predation. And 0:22:22.640 --> 0:22:27.040 what these experiments found was that the quote perceived luminance 0:22:27.240 --> 0:22:30.480 of the frogs was the big thing that really changed, 0:22:30.520 --> 0:22:35.800 and it changed depending on the background compared to opaque frogs. 0:22:35.920 --> 0:22:37.720 So I think one of the really important things to 0:22:37.800 --> 0:22:41.639 understand here is that the translucency of the glass frog 0:22:41.760 --> 0:22:45.480 doesn't actually change the color of the frog very much. 0:22:45.600 --> 0:22:48.200 I mean, it's basically most of them have some kind 0:22:48.240 --> 0:22:52.639 of green or green yellow coloration pattern and that pretty 0:22:52.680 --> 0:22:56.600 much stays the same. What actually changes is the amount 0:22:56.720 --> 0:22:59.960 of light that is allowed to pass through the frog, 0:23:00.080 --> 0:23:03.440 and specifically parts of the frogs such as the outlines 0:23:03.520 --> 0:23:07.639