Speaker 1: Welcome to Creature Future production of iHeartRadio. I'm you're a
Speaker 1: host of many parasites, Katie Golden. I studied psychology and
Speaker 1: evolutionary biology, and today on the show, we are answering
Speaker 1: some listener questions, and by we, I mean me and
Speaker 1: all of my parasites. Uh, Guys, you send to me
Speaker 1: your wonderful questions and I try my best to answer them.
Speaker 1: If you have a question and you're thinking, wait a minute,
Speaker 1: I want my question answered, why don't I get my
Speaker 1: question answered? Well, listen, it's easy. You send me an
Speaker 1: email at Creature Feature Pod at gmail dot com, and
Speaker 1: I answer as many of them as I possibly can,
Speaker 1: which is often all of them. And so yeah, just
Speaker 1: send me your questions, and thank you to everyone who
Speaker 1: has sent me questions. I'm going to answer some of
Speaker 1: them today. So here we go, Hi, Katie. I read
Speaker 1: somewhere that tigers have white spots on their ears to
Speaker 1: act as eye spots to frighten predators. Is that true?
Speaker 1: And if so, what preyed on tigers in the past. Also,
Speaker 1: I just saw the spotless giraffe and it is super
Speaker 1: cute and got me thinking, what color would a stripeless zebra?
Speaker 1: Be all white, are all black? I love your show
Speaker 1: and I have been listening two past episodes from Taylor. Hi, Taylor,
Speaker 1: thank you so much. I really appreciate your question and
Speaker 1: for listening to the show. Yeah, this is a great
Speaker 1: This is an excellent question. So the eye spots on
Speaker 1: tiger ears, I don't necessarily want to call them eye
Speaker 1: spots because they may not necessarily be that. They certainly
Speaker 1: look that way because they have a contrasting black and white,
Speaker 1: So they do kind of appear to be similar to
Speaker 1: eye spots. But what are they for? They may serve
Speaker 1: several functions. One hypothesis is that it is a clear
Speaker 1: signal that makes it easier for conspecifics, which means members
Speaker 1: of their own species, which means other tigers to identify
Speaker 1: each other. It could be useful for cubs to follow
Speaker 1: their mother, or to for adults to find a mate.
Speaker 1: Another non mutually exclusive theory is that it is used
Speaker 1: to threaten rivals, which would be other tigers. I really
Speaker 1: find the positive signaling theory a bit more compelling, you know,
Speaker 1: or perhaps some kind of protection for tiger cubs. I
Speaker 1: don't think the adults necessarily need to use them for protection.
Speaker 1: And if it's something where it is to intimidate rivals,
Speaker 1: it would be a little odd given that if tigers
Speaker 1: are used to being around conspecifics, it would seem like
Speaker 1: that signal would not necessarily scare off other tigers. But
Speaker 1: perhaps early in their evolution there were genes for icepot contrast,
Speaker 1: which was indeed used for defensive signaling, but as they
Speaker 1: became larger, it was used more for communication with members
Speaker 1: of their own species. So onto the question about a
Speaker 1: stripeless zebra. So a stripeless zebra, in my opinion, it
Speaker 1: would most likely be black or brown. But saying a
Speaker 1: stripeless zebra, let's dig into that a bit so zebras,
Speaker 1: in addition to having black skin, also has these black
Speaker 1: furry stripes. But they also have these white furry stripes.
Speaker 1: So it seems that on average, mutations and zebras that
Speaker 1: alter their stripes usually caused them to lose white fur
Speaker 1: and default to being melanistic. The exception would be an
Speaker 1: albino or lucistic zebra. So there have been zebras documented
Speaker 1: with a color mutation that turned its white stripes into spots.
Speaker 1: It's very cute. If you look up spot at zebra,
Speaker 1: you can probably see an image of it. The real answer, though,
Speaker 1: in terms of being stripeless, is that stripes on a
Speaker 1: zebra aren't so much painting on a blank canvas, but
Speaker 1: rather a complex diffusion of melanocytes and other pigment creating
Speaker 1: cells that occur during zebra's evolutionary history. So the extinct
Speaker 1: zebra cousin, the quaga, shows a more complex picture of
Speaker 1: how zebra coloration may have come about. So the quaga
Speaker 1: has brown, white, and black coloration. The stripes appear to
Speaker 1: be white given that brown is the predominant color, but
Speaker 1: it also has a white belly. So really what we're
Speaker 1: seeing in terms of zebras or the quaga is the
Speaker 1: distribution of pigment producing cells. So is a zebra white
Speaker 1: with black stripes or black with white stripes? I would
Speaker 1: say it's neither or both. Let's actually look in to
Speaker 1: how stripes and spots and other patterns form as an
Speaker 1: animal develops. So obviously this is a result of genetics
Speaker 1: and evolution. There may be selective pressures put upon animals
Speaker 1: to form these patterns, either as defense or camouflage, or
Speaker 1: in the case of zebra, potentially disruptive coloration. There's a
Speaker 1: couple things that the stripes may help out with. One
Speaker 1: is that it makes it difficult for a predator to
Speaker 1: pick out an individual zebra and to understand which direction
Speaker 1: the zebras are running in. And also it may make
Speaker 1: it more difficult for a mosquito to land on a zebra.
Speaker 1: The disruptive stripe coloration confuses mosquitoes and other bugs, and
Speaker 1: so that may protect the zebra both from large predators
Speaker 1: and tiny predators. So how do these patterns get printed
Speaker 1: out on animals? Right? Like? You have your zebra stripes,
Speaker 1: you have your spotted giraffs, you have fish that have
Speaker 1: stripes and spots. How do these patterns come out? Right? Like?
Speaker 1: Obviously nobody's going in with a paintbrush to give these
Speaker 1: animals their patterns. So there's actually some really interesting and
Speaker 1: complex physics and math at play here. So Alan Turing,
Speaker 1: the famous computer scientist, came up with a diffusion theory
Speaker 1: when it comes to animal skin patterns. The idea is
Speaker 1: that pigment cells would diffuse like die diffuses through water
Speaker 1: throughout the tissues of the animal as it is developing.
Speaker 1: The problem with the diffusion model is that it generally
Speaker 1: would result in fuzzy patterns, not the sharp crisp patterns
Speaker 1: we see from zebras to zebra fish. So currently biological
Speaker 1: engineers are looking into this. So researchers Benjamin Alessio and
Speaker 1: Akurgupta at the University of Colorado, Boulder have tested a
Speaker 1: model of pigment distribution called diffusiophoresis the movement of molecules
Speaker 1: through different mediums, which can result in patterns with crisp edges.
Speaker 1: If you've ever tried to do suminagashi or paper marbling,
Speaker 1: you know that you can let ink float on water
Speaker 1: and then use alternating brushes of ink and surfactant something
Speaker 1: that decreases water tension like soap, and you create these
Speaker 1: rings of ink on the surface of the water, and
Speaker 1: then you can dip your paper or fabric in it
Speaker 1: and then get this beautiful pattern. Of course, biological development
Speaker 1: does not use this kind of technique to get those patterns,
Speaker 1: but the interesting idea that is similar is that there
Speaker 1: may be different chemical concentrations that the pigment cells are
Speaker 1: moving through, meaning that it is interfering with the movement
Speaker 1: and diffusion of these pigment cells, which could result in
Speaker 1: these crisp lines. So researchers think that certain chemical agents
Speaker 1: present during development diffuse through tissues, polling melanocytes or chromatic
Speaker 1: fes or other pigment producing cells with it. So the
Speaker 1: patterns then would be formed by differing concentrations of chemical
Speaker 1: agents that either poll or reject the diffusion of pigment cells.
Speaker 1: So if you've ever tried to clean a couch or
Speaker 1: a chair or some kind of upholstery and accidentally formed
Speaker 1: a ring of dirt on it while trying to clean it,
Speaker 1: you are basically doing a version of diffusiophoresis. So this
Speaker 1: is a theory that has been tested in mathematical models.
Speaker 1: It's yet to be completely proven as the way in
Speaker 1: which animals get their stripes in their spots, but I
Speaker 1: think it is really interesting and really promising. Follow up
Speaker 1: to Alan Turing's original theory, onto the next listener question.
Speaker 1: A question posed on the Internet was how would Mike Wilkowski,
Speaker 1: that little green cyclops monster from Monsters, Inc. How would
Speaker 1: Michael Kowski cry two streams of tears on either side
Speaker 1: or one in the middle bottom. Of course, in media
Speaker 1: shorthand animators would likely do the two streams. Is that
Speaker 1: would be the least distracting from the emotions of the scene.
Speaker 1: But tear ducks on the side seem insufficient for an
Speaker 1: eyeball that big, and while I can come up with
Speaker 1: multiple plausible methods of keeping that eye hydrated, nature is
Speaker 1: often weirder than fiction. But the only things from nature
Speaker 1: I could find were geckos who licked their eyes or
Speaker 1: creatures who have eyes that don't need to be hydrated
Speaker 1: and cleaned. So are there other animals with weird methods
Speaker 1: lubricating eyeballs? So ah, this is from Tegreja, Thank you
Speaker 1: so much. I love this question. So I hardly realize
Speaker 1: that Michael Kowski has one eye because every time I
Speaker 1: see him his face is covered by a logo. But anyways,
Speaker 1: cyclops animals are actually really rare, so having two eyes
Speaker 1: is a huge advantage. You have this bilateral symmetry. It's
Speaker 1: really useful in depth perception and navigation and having a
Speaker 1: wide range of visions. So the cyclops is not a
Speaker 1: super advantageous design, and so we don't see it very often,
Speaker 1: but there are a few cyclopses. When you get really tiny,
Speaker 1: there are cyclops copapods who have a single median eye
Speaker 1: in the middle of their heads. Copapods are tiny teeny
Speaker 1: teenyeniuenie crustaceans and members of these Cyclops copapod genus are
Speaker 1: about the size of a grain of rice or smaller.
Speaker 1: If you've ever seen a silverfish, which is one of
Speaker 1: my least favorite insects, Actually they kind of look like that,
Speaker 1: but really tiny and microscopic. In terms of tear ducts,
Speaker 1: it doesn't seem that they have any. The eye spot
Speaker 1: is extremely simple and they are aquatics, so there's not
Speaker 1: much need for a tear duct. So while some aquatic
Speaker 1: animals have tear ducts and cry, like crocodiles and sea turtles,
Speaker 1: by the way, sea turtles cry out excess salt to
Speaker 1: protect their kidneys, so their crying is not necessarily out
Speaker 1: of emotion or cleaning their eye, but to expunge excess salt. Anyways.
Speaker 1: Cetaceans also have oily glands that protect their eyes, but
Speaker 1: fish and many other species that live in the ocean
Speaker 1: or in bodies of water do not need tears, as
Speaker 1: their eyes are well adapted to salt water or fresh water,
Speaker 1: and they do not need extra moisture or lubrication. But
Speaker 1: most terrestrial animals have to come up with a way
Speaker 1: to keep their eyes moist and clean. So how do
Speaker 1: various land animals cope with the dryness of air? And
Speaker 1: what do I think a terrestrial cyclops like Mike Wakowski
Speaker 1: would do. Well. There's a lot of things that we
Speaker 1: see in terms of eye protection, like eyelids, eyelashes, and
Speaker 1: tear ducts of course that help protect eyes from irritants,
Speaker 1: but some species have different solutions. So, like you mentioned
Speaker 1: to greyha, most gecko species lack eyelids, so to moisturize
Speaker 1: their eyes they have to give them a good lick
Speaker 1: with their long, flexible tongue. But you also have species
Speaker 1: like snakes who do not have eyelids and they can't
Speaker 1: really lick their eyes with their tongue to keep them hydrated.
Speaker 1: But they do have a hard, clear, protective eye cap,
Speaker 1: one that they can actually shed and regenerate along with
Speaker 1: the rest of their skin. And flies clean their eyeballs
Speaker 1: with their forelegs. You may have actually seen them doing this.
Speaker 1: When you watch a fly carefully as its lands, you
Speaker 1: see its little fore legs going around cleaning its head,
Speaker 1: cleaning its eyes. So you can give it a good
Speaker 1: just rub down with your hands if you need to
Speaker 1: clean your eyes. Don't do that, You'll hurt yourself. Our
Speaker 1: eyes are very sensitive. So personally looking at Mike Wakowski,
Speaker 1: I don't think Mike Wolkowski would have tear ducks. I've
Speaker 1: never seen him cry or his eyes water in a movie.
Speaker 1: Someone let me know if I'm wrong about that. But
Speaker 1: given the shape of his eye, it's very bulbous, it's
Speaker 1: very large, it seems like it'd be really difficult for
Speaker 1: a tear duck to cover that whole eye and to
Speaker 1: actually keep that moist and given the size of the eye,
Speaker 1: also there'd be a lot of danger of debris getting
Speaker 1: into that eye. Just the probability of something smacking him
Speaker 1: in that eye is so high that I do think
Speaker 1: he probably would have a hard clear eye cap similar
Speaker 1: to a snake basically like a permanent large contact lens,
Speaker 1: but it covers his whole eye and something that maybe
Speaker 1: he sheds with his skin. Mikeawelkowski probably does shed his
Speaker 1: skin on sort of a monthly maybe bimonthly, right, I
Speaker 1: can only think how he can keep his skin so
Speaker 1: clear and moisturized other than frequent shedding. But also I
Speaker 1: think Mike Wolkowski would have to use other cleaning techniques.
Speaker 1: I mean, it is a big eye. I don't know
Speaker 1: if an eye cap is enough. He'd probably have to
Speaker 1: wipe it with his hands or his tongue. Maybe if
Speaker 1: Michaelkowski is like a species. It's unclear to me exactly
Speaker 1: how monsters inc works. If they're each unique, if they're
Speaker 1: members of a species, if they're all the same species
Speaker 1: but they all have extremely different phenotypes, it is a mystery. Nevertheless,
Speaker 1: I would think that for all of these monsters who
Speaker 1: have huge cycloptic eyes, they probably would have some kind
Speaker 1: of like contact solution. He could squirt on there to
Speaker 1: keep his eye cap clean. Maybe he uses his hands. Uh,
Speaker 1: maybe he has a nictitating membrane underneath his eyelid. We
Speaker 1: know he has an eyelet, he's very expressive, But a
Speaker 1: nictotating membrane is a third semi transparent eyelet that runs
Speaker 1: horizontally across the eye, helping to clean it. So many
Speaker 1: bird species and reptiles have a full nictitating membrane, and
Speaker 1: mammals like cats and dogs have a partial membrane. That's
Speaker 1: sometimes like when you have a very sleepy cat and
Speaker 1: you see it wake up and it's got that weird
Speaker 1: white thing covering half of its eye. That's the nictitating membrane,
Speaker 1: and so yeah, I think Michael Kowski would probably have that.
Speaker 1: And uh, I mean the other I guess eyeball cleaning
Speaker 1: protection moisturizing thing is something that you see in say,
Speaker 1: land snails, terrestrial snails, where their entire ey stock can
Speaker 1: invert and roll back into their head, kind of squish back,
Speaker 1: and that's a way to clean it and to also
Speaker 1: moisturize it with some mucus. I don't think Michaelkowski would
Speaker 1: do that. I can't imagine. It doesn't seem like his
Speaker 1: body is big enough to contain that. I don't even
Speaker 1: know that his eyeball can move in his socket. It
Speaker 1: seems too big. It seems like he has to move
Speaker 1: his whole body to change his field of vision, which
Speaker 1: might be pretty big considering the size of his eye.
Speaker 1: You actually see that in say owls, or actually this
Speaker 1: little primate called a tarsier. They have such huge eyes
Speaker 1: they can't really move them in their sockets, so they
Speaker 1: have to move their whole heads. Mike Wwikowski does not
Speaker 1: have a neck, so I imagine he has to move
Speaker 1: his whole body in order to get that full range
Speaker 1: of vision, which you know, at least he's getting a
Speaker 1: little more of a workout. So this is a question
Speaker 1: that actually talks about a bonus episode that I recorded
Speaker 1: with my friend Alex Schmidt. We have a podcast together
Speaker 1: called Secretly Incredibly Fascinating. If you enjoy this show, I
Speaker 1: am very confident you would also enjoy that show, so
Speaker 1: please check it out. All right, here is the question. Hey,
Speaker 1: Katie was listening to the Crows bonus episode with Alex,
Speaker 1: and it had me wondering the weird Victorian dude in
Speaker 1: their garage that came up with all these group animal terms.
Speaker 1: Is there any chance they were fans of corvids and
Speaker 1: gave them names on purpose that people would avoid eating,
Speaker 1: because it sounds like this perception of them being murderous
Speaker 1: and unkind saved countless lives. This is from PK. Thank
Speaker 1: you so much for the crow's question. So there's a
Speaker 1: lot of crows based phrases like murder of crows, right,
Speaker 1: which is the term for the group of crows. But
Speaker 1: there's also phrases like eating crow or crowing about something
Speaker 1: or other. So where did these phrases come from and
Speaker 1: what do they have to do with crows. So in
Speaker 1: terms of the phrase murder of crows, most biologists sort
Speaker 1: of ignore the silly name conventions for specific species of animals,
Speaker 1: most of us just for fun. There's just a few
Speaker 1: general terms that are used for certain orders or clades
Speaker 1: of animals that biologists actually use, like herds of ungulates,
Speaker 1: flocks of birds, troops of primates, packs of dogs, schools
Speaker 1: of fish, et cetera. So I don't know if a
Speaker 1: crow researcher or covid researcher would refer to them as
Speaker 1: anything other than a flock, but crows have long been
Speaker 1: associated with death in the West, and so it is
Speaker 1: very unsurprising that they got this term of a group
Speaker 1: of crows being a murder of crows. So crows are scavengers,
Speaker 1: but they're omnivores, so they will eat carrion, and this
Speaker 1: is seen as kind of gross, right, two people, So
Speaker 1: they may have been seen in places where there were
Speaker 1: dead humans as well, like graveyards or battlefields where you
Speaker 1: have or maybe even after a plague or illness, right,
Speaker 1: and you have a bunch of human corpses. So things
Speaker 1: that we have an aversion to, right, a bunch of
Speaker 1: human bodies or you know, moldering carrion. We don't really
Speaker 1: appreciate that as humans, and so if we see a
Speaker 1: lot of crows around it, the association is probably going
Speaker 1: to be pretty negative. They're also all black, and they
Speaker 1: have these guttural calls, which may have added to their
Speaker 1: Gothic mystique. I think they're really beautiful, and I think
Speaker 1: that the sounds that they can make are really really interesting,
Speaker 1: because they can make a lot of sounds other than
Speaker 1: just that calling sound, so it can ravens really really cool.
Speaker 1: But there were all sorts of other negative superstitions about crows,
Speaker 1: like how they might peck out your eyes, or that
Speaker 1: they're omens of death. Of course none of this is true.
Speaker 1: You may see a crow with an eyeball in its mouth,
Speaker 1: but that is just because that crow got lucky and
Speaker 1: scavenged and eyeball. They are just as likely to enjoy
Speaker 1: a nice berry or nut, being omnivorous. So the murder
Speaker 1: of crows terminology probably came from the general spooky vibe
Speaker 1: that crows give off. Despite them not being particularly murderous
Speaker 1: at least to each other or to humans, they will
Speaker 1: kill small prey like insects, rodents or baby birds. But
Speaker 1: you know that's what a cat does, So why aren't
Speaker 1: we calling them a murder of cats? But yeah, crows
Speaker 1: are not completely murder free, but they don't murder people.
Speaker 1: They don't generally murder each other. They're not the most
Speaker 1: murdery of animals. I think if we make a hierarchy
Speaker 1: of murder animals. I don't think that the weird Victorian
Speaker 1: who came up with the name was protecting the crows.
Speaker 1: I think the crows already likely had many superstitions surrounding
Speaker 1: them that protected them from being hunted for their meat.
Speaker 1: Superstitions also probably just sort of as an aside, This
Speaker 1: probably did save the lives of albatrosses and other seabirds
Speaker 1: because sailors thought it was bad luck to kill an albatross.
Speaker 1: In fact, the term an albatross around your neck, meaning
Speaker 1: like an issue that is a big pain that keeps
Speaker 1: following you around, is from Samuel Coleridge's nineteen seventy eight
Speaker 1: poem The Rhyme of the Ancient Mariner, in which a
Speaker 1: mariner kills an albatross, causing bad luck in the winds
Speaker 1: to die down around the ship and stranding him and
Speaker 1: his fellow sailors. As punishment, his fellow sailors string the
Speaker 1: dead albatross around his neck, which is a reminder of
Speaker 1: his crime that doomed them. So onto the other phrases
Speaker 1: about crows. Where do these other sayings about crows come from?
Speaker 1: Like eating crow? So eating crow means having to admit
Speaker 1: to being wrong. This phrase likely originated in the eighteen
Speaker 1: hundreds and was probably just to evoke disgust at the
Speaker 1: idea of eating something unpleasant. There's a possible short story,
Speaker 1: a kind of humorous story that originated the phrase, printed
Speaker 1: in eighteen fifty under the title eating Crow. It's about
Speaker 1: a New York farmer who claims he's not picky about
Speaker 1: food and could eat anything, and so, of course, he
Speaker 1: is provoked by his chums who tried to get him
Speaker 1: to eat a crow laced with snuff, which is a
Speaker 1: type of tobacco, And after he eats this dish, he says,
Speaker 1: I can eat a crow, but I be darned if
Speaker 1: I hanker after it, which basically means I can eat it,
Speaker 1: but gross yuck. So it is this possibly this short
Speaker 1: story that popularized the phrase eating crow, but essentially for
Speaker 1: a while the idea of eating crow was unpleasant to
Speaker 1: people because crows are scavengers and they eat carrion. This
Speaker 1: was thought to be kind of a gross food. So
Speaker 1: the idea being you are eating something that may have
Speaker 1: eaten a dead body, maybe even human remains. Its quicked
Speaker 1: people out. So that idea that crows are not good
Speaker 1: for eating probably did save some of their lives, right,
Speaker 1: Because apparently I've read that crow meat actually does not
Speaker 1: taste bad. I wouldn't know. I've never eaten a crow.
Speaker 1: I love crows too much. So what about crowing about
Speaker 1: something or other, meaning someone is bragging, Well, this actually
Speaker 1: has nothing to do with crows. Crow also means the
Speaker 1: call of a rooster, and so the idea that someone
Speaker 1: is being loud and obnoxious in a proud way is
Speaker 1: supposed to be evocative of a rooster crowing proudly right,
Speaker 1: sticking out its little chest, and crowing in the morning.
Speaker 1: So the name crow for the bird we know and
Speaker 1: love probably came from the automotopia of the Old English
Speaker 1: word crawl, which was probably used for multiple bird calls.
Speaker 1: But stuck is the name for crows, probably because their
Speaker 1: call is very, very distinctive and they are also quite
Speaker 1: present around human society. So there you have it, all
Speaker 1: the crow etymology facts that I can think of. If
Speaker 1: you have more questions about animals, animal behavior, your pets,
Speaker 1: why are we got certain ideas about animals, or if
Speaker 1: certain myths or superstitions about animals are correct or wrong?
Speaker 1: Anything about animals or evolutionary biology, you can write to
Speaker 1: me at Creature Featurepod at gmail dot com and I
Speaker 1: will do my best to answer your question. I will
Speaker 1: either do it here on the show in these listener
Speaker 1: questions episodes, or I will write back to you, or
Speaker 1: maybe even both. Who's to say, uh, but yes, I
Speaker 1: really do appreciate your questions. They are really interesting and
Speaker 1: often they have me off on a little research spree,
Speaker 1: right Like, I didn't know about the etymology of all
Speaker 1: these crow terms, and tell you ask this question, and
Speaker 1: I looked all this up so it helps me learn.
Speaker 1: I hope it helps you learn. Thank you guys so much,
Speaker 1: and yeah, I will see you next time. Creature Feature
Speaker 1: is a production of iHeartRadio. For more podcasts like the
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Speaker 1: or hey guess what wherever you listen to your favorite
Speaker 1: shows I do not judge you, and I'm not your mother,
Speaker 1: and I can't tell you what to do, but I
Speaker 1: do love you all very much. See you next Wednesday.