Welcome to Creature Future production of I Heart Radio. I'm your host of Many Parasites, Katie Golden. I studied psychology and evolutionary biology, and today on the show, it's another listener Questions episode. That's my listener Questions episode song. You guys will sometimes write into me some questions about animals and evolutionary biology, and heck, you know what, I answer them because that's who I am. And this week I have some really interesting questions. So let's get right into them.
Although I guess before I do. If you have questions that you really want me to answer, You're you it's just been a thing that's been keeping you up night after night. You're like, please answer this animal question. I I need, I need to sleep. You can write to me at Creature feature pot at gmail dot com with your question, and I endeavor to respond always. Either I will respond to your email or when I do these listener question episodes, I will respond on the air. So
thank you guys for writing into me. Now let's get right into the first question. So here is the first listener email. I have a question about primary colors and how we view them. Are what we view as primary colors? Universal or is it just an emergent property from how our cones are set up. I eat as blue and yellow always make green or is that an effect caused by our r G B cones. Thank you so much and keep up the fantastic work. This is from Matt G. First of all, Hi Matt, thank you. That is a
great question. This is it's very interesting, right. So, like when we see color, it is light entering our eyeballs and hitting sensory cells at the back of our eye what is called the retina, and these sensory cell are called rods and cones. Rods don't have much to do with seeing color. They're mostly used to be able to see in dim light. They're highly sensitive to light, but
they are not so sensitive to color. That's why I like when it's really dark out, like at night, like your sort of night vision, you don't really see color very well. You just see light and dark. But your cones, the other sensory cells in your eyeballs, actually can pick up on colors. And we have three types of cones. So with that information in your head, let's talk a little bit about color. So color as pigments and color
as light wavelengths are slightly different. Of course, ultimately, when we look at a pigment, we are seeing that color due to light wavelength. So light bounces off a pigment enters our eye and that's how we see it. But primary colors for pigments are very different from the red, green, blue, or yellow wavelengths of light in terms of how they
mix and produce colors. So if you mix blue and yellow paint, it will make green, But if you combine blue and yellow light, it actually makes a white light. So if you combine green and red light, you get yellow, whereas green and red paint makes a sort of muddy brown. And if you mix all of the colors of paints,
as you probably know from kindergarten, it creates brown. But if you mix all of the light colors like you have of spotlights and all sorts of different color, and you mix all of them, it's going to create white. So light wavelengths interact in different ways than pigment molecules to create color. So I wouldn't say that primary colors are universal because wavelengths of light don't simply come in like red, blue and yellow or red blue and green.
Primary colors like red, yellow, and blue are based on paint pigments and color theorists came up with these as primary colors. It's not based in the science of light. But even when it comes to light, I wouldn't say there are exact primary colors. So while we sometimes describe our cones as being sorted into three categories of red cones, blue cones, and green cones, meaning that these cones pick up on those types of light, uh, it's actually a
little bit messier than that. A light is a spectrum, so our eyes pick up on the spectrum of wavelengths. So we have three types of cone cells, and they don't each only pick up on one type of color. There's actually a range of light wavelengths that are able
to trigger each type of cone cells. So instead of labeling these cone cells as red cones, blue cones, and green cones, perhaps the more accurate name is L M and S cones, which stands for long, medium, and short, referencing the types of wavelengths they tend to be sensitive to. So S cone cells. Short wavelength cone cells mostly pick up on blue light because blue light tends to have
a shorter wavelength. But more precisely, there's like a bell curve from around four hundred nanometers wavelength to five thirty nanometers of wavelength that these s cones can but don't always pick up on. So this is the same case with the medium and long cones. In fact, they overlap with each other quite a bit. So, uh, these are
the green and red cones. The M cones, the medium cones pick up on a good amount of green light, but they can also pick up on some yellow and red, and the L cones, the long cones pick up on mostly red light, but they can also pick up a little bit of yellow green. So there's overlaps of the ranges of the type of light that each cone can
respond to. Not only is each cone capable of picking up a spectrum of light, the color you perceive is actually determined by the combination and strength of activity of your cones. So say you've got some short wave length cones that are picking up some blue, and then you've got some of the long wavelengths cones that are picking
up red. You may see something like kind of a purply color or something, or or you know, the the number of of cone cells that are being activated or the strength of the activation is going to determine how bright something is, what color is going to be, the hue, and that's why we can see an incredible, nearly infinite range of colors, shades, and his. It's a little bit
about human eyeballs. Humans are trichromats. We typically have three types of cones that detect three ranges of light, those S, M, and L cones that I described earlier. Most mammals are actually die chromats, having only the S cones the short wavelengths, and the ELK cones the long wavelength cones. Um. But there are also monochromats, animals who do not perceive color and seeing black and white. Now you may have heard at some point that dogs see in black and white.
That's not true. Dogs are actually die chromats, so they do see a range of color, maybe not as much of a range as humans do. But in terms of monochromats, animals that truly only perceived in black and white. Uh. These are typically cetaceans like whales and dolphins and pinnipeds, seals, sea lions, and walruses. But before we get too smug about our amazing color vision, there are also animals who have more cones than humans. These are tetri chromats, which
include certain species of birds, reptiles, fish, and amphibians. Uh. In fact, it's thought that the common ancestor to all vertebrates was actually a tetrachromat having four types of cone cells, but that many mammals lost these extra cones, and the reason perhaps that we lost these extra cones is the nocturnal bottleneck. This is the theory that most mammals were forced to become nocturnal due to predation and competition with dinosaurs.
So tetrachromats having those four combes can see a wider range of light wavelengths, and often this includes you V light. However, you do not have to be a tetrachromat to see u V light. All you need is at least one of your cone cells to be sensitive to that light and for your eyeball to actually allow you V light
to pass through the lens. So, for instance, human cones can theoretically detect u V light, but the light is actually blocked by our lens, So people without the lens or with an artificial lens are actually slightly sensitive to UV light and can see a sort of bluish white or violet light, but that's not to say that this is the same as say, another animal who can see UV light, because our cones may not be quite as sensitive to UV light or pick up the full range
of UV lights, so a tetra chromat might see this light in a much richer way. We just simply don't know what it's like. Because we're not a bird. We can never get into the brain of a bird. Well, I don't want to say never, but with our current technology so far, we have not avatar into the brain of a bird, even though I would love that. That's my dream. Well, we're gonna take a quick break, but when I get back, I'm gonna talk about some more or less or questions and answer them to the best
of my ability. So here is an email in response to my recent Falling style episode. This listener wrote, I like this as usual, but you left out flying fish. I wonder if you could do an entire episode about flying fish. There is a southern constellation of Volands, the Volands the flying fish, but there are no legends associated with it. It's a modern one invented by astronomers during the Age of exploration. Astronomers made up a lot of
constellation which are no longer quote official. Today, there are eighty eight official constellations, many of which are animals, and many of the constellations no longer official were also animals, such as the cat, the toad, and the flamingo. There are not any plant constellations. Wikipedia has an article on the former constellations. Could you do an episode about the constellations?
This is from Steven M. Thank you so much, Steven. Honestly, it sounds like you know way more about constellations than I do. I love constellations. I love the stars. Typically I can't see them because I live in the city and light pollution prevents us from seeing the full range of stars, which is kind of sad. But the last time I went up into the mountains, I did have
a wonderful view of the sky. I actually went to like a a star tour thing where they told you about all these constellations and all these stories like these ancient I guess tales, and it was it was still kind of difficult, uh, And I really can see why it was such a wonderful storytelling tool. You're lying there in the dark, maybe it's a little spooky or a little scared of predators, but then you have all these bright stars, and so you can point to them and
connect the dots and come up with stories. And it's something that while it's not true that these stars never change. Of course, physicists would tell you that there is of course change in in the stars and in the night sky, but it's very slow. And they are such a wonderful kind of constant thing that we all share to look up at. But I sadly don't know that much about constellations. Yeah, maybe I'll do some research into it and see if I can, you know, do an episode about the real
animals behind these constellations. But onto the other aspect of your question, which was flying fish, and those I do know a bit about, so I agree that flying fish are amazing. They are a family of fish found all over the world in tropical and subtropical oceans. They tend to be around seven to twelve inches long, which is seventeen to thirty centimeters, which makes them appetizing snacks for larger fish. So they have developed a strategy. They will
take to the skies. They will launch themselves out of the water, spread these amazing fishy wings and glide incredible distances. So their pectoral fins have evolved to splay out like membranous plane wings, and they can leap into the air and glide amazingly long distances up to around around a hundred and sixty feet or fifty meters at a time, which is just incredible. Uh. In fact, some of the records for flight are even longer due to having a
nice updraft from say like a large wave. They have been recorded to have reached up to one thousand, three hundred feet or four hundred meters. That's I mean for something that is a fish, right, it is not supposed to be flying around. That is incredible. They're also fast. They can go over thirty five miles an hour or fifty six kilometers an hours, so these are serious flyers like I would. I mean, it's true that they are gliders.
They don't necessarily get much altitude when are out of the water, and they glide rather than flap their wings. But it is for a fish, I mean, come on, that's incredible. Uh. Those amazing wings that are so aerodynamic and great for flying aren't so great for swimming, so they usually just keep them tucked at their side and
do not use them for swimming. Just use torso movements and their um their tails to swim around, and it is it's incredible given that they are just like they are able to launch themselves clear out of the water just from the flicking of their back tails and their abdomens um. While their flight can get them out of sticky situations with predatory fish. Sometimes they will then get picked off by predatory birds. So it's kind of like out of the frying ocean into the frying sky. Yeah,
that makes sense. Anyways, onto another list or quashed on. So Justine s to me about a viral video of a two can with c through skin and asked if it is real. Uh So, yes, this video of a two can where they pulled back at the nape of its neck and it's you can see right through the skin. It is a real video. But I think it is important for some context lest you think that, uh, two cans like under their skin are just kind of like
look like they're made out of glass or something. So in the video, someone parts the feathers on the nape of a two cans neck, revealing this c through membranous skin. Uh So, first of all, it's not necessarily a two can specific trait. Birds in general have very thin skin. They evolved to become very light, you know, these light hollow bones, thin skins because they had to drop a lot of weight, a lot of ballasts so that they could fly. So, yes, birds have very thin skin. They
do not like to be insulted. Uh. And also, if you shine a bright light source behind a fold of a bird's skin, it becomes translucent. You can even, like for some small birds, shine a light on the top of their heads to be able to see how thick their skulls are. So the reason it looks so remarkable with the two can is that two cans. Uh. It's the feather pattern of the two cans. They do not have any down. They just have an outer layer of feathers that grow in rows. And in between the rows
of these feathers, there's actually no feather growth. Um. Normally this isn't so noticeable because the feathers will overlay each other and hide the skin. But if you part the feathers, you can see bald areas of skin where are there where there are no feathers growing. And if you gently pull the nape of their neck and shine a light
through it, the skin is translucent. Now in the video, it may look like you can see like the bird's spine or something, but that thick part that you can that is not see through and the skin is actually not its spine. It's a thick band uh that is uh, this vascular area from which the feathers grow. So that's like that's the row that the feathers are all growing out of, and it's kind of thicker, vascularized, So it is not its spine. You're not seeing its skeleton through
its skin. You're just seeing sort of a flap of membrane of skin. I mean, if you sort of shine a light through a thinner part of your skin, like through your palm or something, or through a finger, you can see. It's not transparent or translucent, but you can see like some veins. You can even like if you shine a light through an ear or something, you can
see some blood vessels at times. So it's like, you know, this is not something unique to uh two birds or to this two can, but for sure, uh in this particular case, the combination of the two can not having feathers, they're having sort of a thin uh nape of its neck and having very thin skin yes, that skin is translucent. So we're gonna take a quick break, and when I get back, it's hey, guess what more or less sir questions, see you soon. So we are back. Uh, And here
is another listener email that I received. I suggest you do an episode on legless lizards and how they are different from snakes. This could be a fun look at parallel evolution. Thank you for a great part. Thank you for a great podcast, Daniel L. So, Yeah, this is an amazing thing. I love legless lizards, all of them. Um, this is a great example of convergent evolution. So the distinction between parallel and convergent evolution is it's I personally,
it always confuses me. It's kind of nit picky and tricky and like, there's technically a difference, but it's really hard to kind of make that determination. And sometimes they are like debates about it. But uh, it's subjective. But
this is my best way of explaining it. Convergent. Uh. The reason I would say that the case of legless lizards and snakes is a case of convergent evolution is that the last common ancestors of snakes and lizards had legs, and then snakes and lizards diverged, and then the UH snakes developed likelessness on their own, and then the lizards then developed likelessness in some species, so then they reconverge.
So like when they like diverge and then reconverge with traite UH or they start off kind of looking different and then converge, that's convergent evolution, whereas like with parallel evolution, I would say that's usually like, you know, they don't they don't necessarily have that like initial divergence or initial
separation in terms of traits. Their traits kind of like um, you know, they may they start at point A and they both independently get to point B, whereas with convergent evolution, they start at point A and point C and then both of them come to point B. It's not that's maybe not the best explanation of it or the most encapsulates all aspects of it, like the relatedness of species
and so on. But for me, that's kind of a good heuristic to tell the difference between convergent and parallel evolutions. So in this case, I would say legless legless lizards UH and snakes are an example of convergent evolution. So legless lizards are indeed not snakes. Snakes are not simply defined as lizard without legs. Even now that's kind of what it seems like they are. So snakes diverged from
lizards around a hundred and fifty million years ago. In fact, you can see these different evolutionary stories when you compare legless lizards with snakes. There are some significant differences, such as legless lizards having ear holes and eyelids, which snakes do not have. Also, uh, legless lizards have really long tails whereas snakes do not. Know this sounds weird, right, Like what what part of the snake is the tail versus just a more snake. It's not that clear, but
snakes actually have relatively short tails. The tail part is behind their pelvis and does not contain any internal organs. It's a tail, whereas the rest of the snake, It's like, this is its body, it's torso, it's above the pelvis, it contains or internal organs, it's stomach, etcetera. Um. So, like the tail part is a different part of the snake. Even though it all seems like just like one tube. Uh, it does have an internal structure of course, uh not
only did lizards and snakes independently evolve leglessness. Even among the legless lizards, there are many cases of independent evolutionary paths that all led to no legs, which is incredible. Apparently, ditching legs when you are a burrower, like when you burrow in dirt, is a fairly popular and successful evolutionary strategy. So there are at least eight groups of lizards who have all independently lost their legs, and each group contains
multiple species. Some legless lizards look fairly snake like, some look kind of chunky, uh, they're like thick, and some kind of look like pink worms. They're really wonderful. It's a very diverse group of animals. Um, there are also lizards. In fact, it's such a popular strategy that it seems
to happen really quickly. There are Australian lizards called skinks that essentially became legless in around three and a half million years, which that sounds like a lot of time, but in terms of evolution, uh, that is very very short. So it sounds counterintuitive, right, Like, legs seem like a
really good evolutionary trait. Why would you get rid of something that helps you get around well, if you spend a lot of time in like sand or soil, essentially just kind of swimming around and sand, having legs doesn't necessarily help you that much. And so by getting rid of the legs, you've made yourself more streamlined. Uh, you've you know, it's always costly to have extra parts and evolution. You typically you don't keep apart um that you don't
need because it is it usually costs something. Now, sometimes you do. You'll have like a vestigial organ or a vestigial body part if it's not really costing you that much and it doesn't affect your survival. Um. But generally speaking, if you have something that is not helping you and it is maybe even getting in your way, you will become more streamline. You will lose that. So uh, this
is uh, this has happened in many different animal lineages. Um. I mean, in fact, like we talked about swepts uh recently, but their little legs have become almost vestigial. They still use their little feet to like hang onto the sides of buildings and stuff, but they cannot walk on those legs. They really can only fly and basically cling onto sides of buildings with these little tiny uh hook hooks on
their feet. Um. And in fact, this like snake body right is not only is not unique to reptiles, there are also amphibians. These are called scis aliens. They are a group of amphibians that look like a cross between a worm and a snake, and they are legless amphibians, so they live underground and despite looking like large worms, their diet is typically made up of worms. So I guess you are what you eat, although yeah, I don't know.
It's like I'm trying to imagine like these sicilians, which are basically like big worms, just eating a small worm. It feels wrong in a way, even though I know it's right. Anyways. The Sicilian species buller and Jewela titana uh, found in southeast Kenya, is a grayish blue worm like animal. It's an amphibian of course, with segmented rings kind of like I don't know if there's any dune fans out there, but it kind of looks like a dune worm but small.
It's it's pretty small, um, you know. It's it's like it looks like an overgrown earthworm. And female els lay eggs but they have a special trick when it comes to childcare. She grows a special layer of fatty, nutritious skin. Uh, and then it allows its offspring to nibble this skin. So it's like, it's always fascinating to me when animals like of course, mammals have lactation, right, we feed our
young through memory glands that produce milk. But mammals are not the only ones that like produce some kind of bodily affluence that we feed our young. Uh. The Sicilian literally feeds it like mom jerky, jerky made out of the mother. Uh that it basically the young can just kind of peel off full chunks of it and nibble on it and it gives them nutrition. Of course, there's like birds that have developed crop milk where they uh you know, create this sort of fatty, lipid rich slurry
and their crop and regurgitated for their young. So uh. And some animals, like certain spiders, we'll just let their young eat them oh once they hatch. So you know, gosh, the love of a mother, I don't know, I mean, I you know, I feel like I have a maternal instinct. I'm not sure if I had little baby eat my skin just gonna put that out there. Well, that is it for a listener questions. But of course we have to do the Mystery Animals sound game. Now. I'm sorry
to say there is no new Mystery animal sounded this week. Um. I will reveal the answer to last week's Mry animals sound actually next week. But hey, that just gives you an extra week to try and guess last week's Mr Animal sound. But here is a refresher for what that was if in case you missed it. Last week's hint was this the Sharks and the Jets are about to have a showdown. They really ought to calm down. Uh. So that that there's that. Uh here's another hint. It's
not aliens. But if you think you know who's squawking right to me at Creature Feature Pod at gmail dot com. You can also write your animal questions again. I will try to answer them either right back to you or hey, even answer them on the podcast. Thank you guys so much for listening. I really appreciate it. I hope you like these listener Questions episodes. It really helps me out because,
first of all, I really enjoy seeing your questions. It often sends me down on a research rabbit hole, so I love that, but also it's it's a little bit chill, it's a little laid back. It gives me a little breather while also being able to talk to you guys like directly, which I love. Um. So yeah, thank you so much for listening. And if you're enjoying the show and you leave a rating and review, I am super super grateful for every one of you have done that.
It helps the show out immensely, and of course, like when I read the reviews, it makes me feel happy. It makes me feel like I am talking to people and not sending my voice out into the void, which you know, I guess the void is fine too, Hi void. Anyways, thanks to the space Cossacks where they're super awesome. Song Exo Alumina Creature Feature is a production of I Heart Radio. For more podcasts like the one you just heard, visit the I Heart Radio app, Apple podcast or Hey guess
what alright, listen to your favorite shows. I'm gonna judge you not in your that is your business. I will stick out of your business. See you next Wednesday.