Listener Q's: Owl Eyes And Alien Guys

my ability. So, first up is this question. Growing up, I knew that typically we see owls during twilight hours and or at night, but just recently I had a co worker tell me that owls can choose whether or not they want to be out during the daytime or nighttime, and depending on what the owl the sides, its eye color changes. Accordingly, this person told me that daytime owl's eye color will be yellow and nighttime owl's eye color will be black. Is this true or is it a myth?

Melissa H Thank you so much for your questions. So first of all, uh, you should definitely call out your coworker because this is not exactly true, and you should call them out in front of everyone and point of them and say you lie to me, you liar, No, don't do that. So it's not true that an individual owl's eyes can change color based on whether it wants to be out during the day or night, but on the species level, yes, their eyes are different based on

their habits. So different owl species have different sleep wake habits. Some are nocturnal, meaning they're most active at night, some are crepuscular, meaning they're most active at dawn and dusk. There are only two species of owls who are dire all like us, meaning they sleep during the night and are awake during the day, and these are the northern hawk owl found in the Northern Hemisphere and the Northern

pygmy owl, a little owl found in Northwest America. The iris color in owls tends to correlate to the owl's wake sleep habits, so nocturnal species are more likely to have dark irises than crepuscular or diurnal owl species. The theory is that the dark irises allow the nocturnal owls to be more camouflaged in the night, as their irises are less likely to show up. While there are nocturnal owl species with yellow or gold irises, these are more unusual.

Researchers have been able to establish a trend amongst nocturnal species favoring worker irises, and they believe that the evolution of dark irises is likely due to owl species evolution towards nocturnality. So it sounds kind of like your coworker may have heard this and either it wasn't explained to them all that clearly. So it is not a single individual owl cannot at will change its eye color, but different owl species do have different colored irises based on

whether they are nocturnal or crepuscular or diurnal. Although there are it is certainly not a hard and fast rule. There are nocturnal owls who have lighter irises and vice versa. But generally speaking, those dark irises really help out the nocturnal owls to keep those bright irises from alerting their prey that they're coming for them, because owls like to be swift and unseen death for many mice. So some bird irises do actually change color throughout their life as

they mature. In some species, young birds are born with brown irises, which eventually develop into yellow irises as they mature. This is the case for golden eyed ducks, bald eagles, and ring build goals. Cooper's Hawk irises actually start out as yellow as youngsters, and they turn red as they grow into adults. The theory behind this kind of eye color change with maturity is that the change in the iris may help with sexual selection by being an honest

indicator of the bird's maturity. But there are some animals whose eye colors will change back and forth throughout their life, and this is the case with the reindeer. So not a bird, a reindeer. Their eyes are gold in the summer and blue in winter. The change in their eye color is not due to pigment, but the structural changes in their timpeedeum, a membrane of reflective tissue behind the retina.

By reflecting light, it helps amplify dim light, making it more likely to hit a photoreceptor cell, so the animal can detect light in dark conditions. So essentially they have a mirror like membrane at the back of their eye that will reflect light back out and that allows them another shot at hitting one of their photoreceptor cells. So you've probably seen a timped them in the glowing eyes

of a cat at night. So for these reindeer during winter, it's very dark, and so they keep their pupils more dilated all the time, and that constant dilation of their eyes actually causes ice rain and pressure to build up, which is a temporary case of glaucoma. This also squeezes the tapped um, which changes its structure, so instead of reflecting yellow light, it starts to reflect blue light and

changes from yellow to blue. We actually talked about the difference between pigmentation and structural coloration in the podcast I did recently with Daniel Whitzen, a particle physicist, called Physics Is Why Nature Is Pretty? I think that's the title.

But yeah, so you can have these changes in physical structure of something like a membrane or a lens or or a crystalline structure, and that will actually cause a change in how we perceive that color because it will bend the light differently, will reflect or refract different types

of wavelength. So when they have this kind of squished tampeedum and the turn due to eye strain, because their pupils are constantly dilated, it has changed it such that it refracts that blue wavelength rather than that more yellow wavelength. So I think that's really interesting, and yeah, thank you so much for the question. Even when someone it maybe has a here's an Old wives tale or has a misunderstanding about nature, usually if you dig into it, you'll

still find something really, really amazing. So onto question two. That's my question too. Song Okay, Hi Katie, thank you for your super great show. We and my family love spiders and possums, and I myself actually love earwigs too, because they're just so cute with their kind of idiotic curiosity braveness mixed with how well they take care for their littles. I've been fascinated by convergent evolution, especially hawk moths and hummingbirds wild that morpholo agically and behaviorally they

match so well given how far apart they are philo genetically. Wow, I can't believe I pulled that word out of my brain. I blame your show. So if we found a planet that's Earth's twin and has one dominant intelligent technological species, would it possibly be humanoid? Obviously science fiction creators seem to think so, or they just write about blue women because of all of the best actors on Earth are already humanoid. Anyways, thank you a million times. I never

miss an episode. Jan Thank you so much. You're very sweet, and I love your question, so it is a really fascinating question. Obviously, I've never seen an alien myself, so I cannot answer for sure, but I do think there's a very good chance of an alien who evolved on like Earth Point too could be very humanoid, and I believe in the idea that they would probably be a terrestrial maybe kind of human ish human adjacent kind of animal, if it were able to develop a civilization like we

have with technological advancements. Now, this doesn't necessarily extend to all intelligent life. Obviously, there's a lot of intelligent life right here on Earth who don't really have technologies so to speak. They may have tools, but not technology, And so I can imagine a lot of really interesting alien life that wouldn't necessarily have technological advancements, but would still be really intelligent and may look completely different from humans

or anything else we have on Earth. But in terms of a specifically an alien creature evolving on Earth Point to you know, carbon based life form same conditions and evolved to have a technological society, I believe yes, it's very likely to be at least humanoid, somewhat human looking maybe not exactly like humans, probably a lot of weird differences. But here's here's why I think it's likely they at

least share a few key traits with us. So there are a lot of intelligent species on Earth, but there are factors that may prevent them from developing a civilization like we have. So take octopuses. They are very clever, very intelligent, but there are a few issues that would prevent them from, say, developing a technological civilization unless they went through some pretty dramatic evolution, even more dramatic than say,

from a primate to a human. So octopuses live in an aquatic environment that makes civilization building tasks really challenging to impossible, such as trying to create lasting structures or fire or agriculture. That's all really really difficult underwater. Obviously, you can't even really make fire underwater, and that can be really important for technological advancement. And in addition to that, octopuses have a couple other things that would prevent them

from developing a utopian octopus civilization. As much as I would love that one, is there pretty solitary. They did not evolve to be social, and that is a real bummer if you're trying to make a civilization because you need help. And another issue is their lifespans are so gosh darn short. They usually only live a year or so, maybe a little over a year, and they will die after reproducing, and it's both very sad and heartbreaking. But you also, I think would need a much longer lifespan

to ever hope to have a civilization. So unless the octopus went through some really rigorous changes, maybe even became terrestrial, then maybe they could develop into a more society building type animal, but it would be difficult, it would be a long journey. Terrestrial life, meanwhile, gives you a lot more opportunity to create things like lasting structures, to create tools that you can store somewhere, and they don't, you know,

drift away. Um. But why, I mean, we have a lot of terrestrial life, right, We have a lot a huge diversity of terrestrial life, from flying to slithering to hopping everything. So why would a civilization ready animal be humanoid and not something like a super intelligent snake or spider or a super society of dogs. So having hands and the ability to manipulate in craft tools I think

is really important. If you want a technologically advanced society, you can obviously have a social group of animals like wolf packs have these complex social groups without having hands, but they can't really build things complex tools. Um. Of course, there are a few non primate species who can build tools, like New Caledonian crows and other intelligent birds who are also highly intelligent puzzle solvers and can be highly social

and are also capable of complex language skills. So it seems like birds might be a prime candidate for building like a technological society. So why not a civilization of birds? Well, I would think that flying is going to get in the way of them ever really evolving to the level of humans. Uh. While flying is a wonderful adaptation, it is a costly one. It consumes a lot of energy, and our brains are huge energy hogs. If you want a big brain, it's going to take a lot of energy,

like a fancy computer graphics card and processor. So if you want a huge brain that's really capable of next level technological stuff, you probably don't want to invest as much in flying. And so if you're a flightless bird, uh, maybe you'd have a better chance, but you'd still have the issue of you don't have hands, you have a beak, which you know, birds can use their beaks to develop tools, like take a twig and kind of bend it into

a hook. But that's it's I mean, the the motor capabilities of a hand versus a beak are quite stunningly different. So there's a lot more you can do with a pair of hands to like with one beak. It's relatively hard for them to sort of do actions together. I mean, there are some birds who can like push their beak against their feet or against the ground and get a little more leverage. But having those two really motor capable, dextrous hands are very very useful for bill holding complex tools.

So I think basically what you would need for a not just an intelligent species, not just a social species, but a species capable of building a civilization with technology, you would need two eyes. Uh, because having that depth perception UM I think is really important to be able to um basically build and plan things. I think you

wouldn't need more eyes than that. You probably actually wouldn't want more eyes than that because more eyes, more sensory tools, more sensory equipment means investing more brain power into visual processing, which takes resources away from the cognitive and social centers of the brain. So you kind of you wanna be careful about what you are in vesting your brain power in, and for a civilization, you need a lot in terms

of that social and cognitive processing center. So if you invest too much in the visual center, you're going to have less for those centers of the brain. You would also need some kind of complex language. This could be achieved through vocalizations. I think it could also be achieved through sign language, some kind of visual language that you

can create signs and symbols really quickly. Um. If you have some appendages that would be capable of creating a language out of gestures like human sign language can do, I think that would be UM. I think that would be enough in terms of being able to communicate. Vocalizations have the advantage of being able to alert your group of danger from afar, Like a lot of primates will

have alarm cries because there's a hawk above. So that's probably the fulness of that is probably why we developed a vocalization type communication rather than all humans developing sign language. Although sign language is a very it is a form of language that comes very naturally for us to develop, so you can have there have been instances of like groups of children who are deaf, like in a deaf school,

spontaneously coming up with their own sign language. So that is a really innate ability to create a language out of whatever tools we have, whether it's vocalization or signs. So I could see good arguments for either vocalization based language or sign based language in some kind of alien species in Earth two point oh uh, chemical communication like that we see with ants and many other animals, such

as pheromones. I'm not entirely sure if that could be if that would be enough to develop into a really complex, dynamic language, because vocalizations or signs have the advantage of being able to like be quickly expressed in real time and quickly read in real time, whereas a pheromone is kind of a thing you leave out, uh for something to happen upon. So you would need to basically be able to puff out rapid pheromones and a complex stream

of pheromones that your conversation partner could quickly detect. And I think that's it may be more complex and difficult than sale language that is either vocal or through sign and so those I think are the requirements for this like Earth point to intelligent species? Would this happen? Like? Is it likely that you would have another basically like civilization building species on Earth point to? Or are we sort of supremely lucky or unique? In my opinion, I

think it's actually fairly fairly likely. I think that you know, there is a lot of evidence that brains and eyes evolved multiple times independently. We had eyes kind of coming up over and over again, uh, and complex brains kind

of evolving independently over and over again. And so it seems like with similar evolutionary pressures, as long as you could get life to start on this Earth, which you know, may not be a guarantee, but if you could, I think it's probably pretty likely you would get intelligent species.

And if the Earth lasts long enough and evolution runs its course, I think having a species that ends up uh the selective pressure favoring so much uh socialization and intelligence and cognition that you actually start to get to civilization levels of intelligence, I think that's pretty likely, if not maybe maybe even inevitable. I don't know if I would go that far, but yeah, maybe, And you know,

I think that these earth point to civilization. They may not look exactly like us and sound exactly like us. I just think they would have some striking similarities. So maybe not like a blue human, but maybe they would have two eyes. They may actually be front facing eyes like ours are, to allow us depth perception for hunting. They would probably have a big head and a big brain.

Maybe their offspring would be born prematurely to accommodate the big brain by allowing their skull to kind of be squishy, just like our offspring. And maybe they would have two arm appendages with some kind of dexterrous grasping ends. They don't necessarily have to be hands with fingers, but something that allows them that fine precision of making tools. And

would they be bipedal? I mean, I think it's certainly possible, because you know, we developed that bipedal walking behavior, probably so we could do things like hold our tools as we walked. So I would expect there to be at least some capability of being bipedal, even if they're not always bipedal. Uh, you know, would they be like a centaur where they would have like four legs and then two arms. I don't know, I think that that's possible.

I suppose I would think that would make developing a sort of immature, big brained offspring kind of more difficult to be able to kind of, you know, hold and carry something of those proportions. But you know, it's it's you know, maybe that would be possible. I I just my sense is, and maybe I'm just not being creative enough, but my sense is, Yeah, it would be something may

be similar to us, maybe harrier, maybe less hairy. Lots of possibilities for differences, you know, different skin texture, like could we have scales, Yeah, sure, I don't know. Would we have a completely different kind of vocalization, completely different sorts of facial expressions and bone structure? Yeah, absolutely, I

think that's possible. But yeah, I think there would be some really interesting, really bizarre similarities between us and an alien species that evolved on an earthlike planet, which I think is interesting. Onto the final question of the day, not the final question in general, There's always going to be more questions. I don't think there would ever be a final question that would be sad and bad. It'd mean like the universe would implode or we'd learn everything,

and both of those sound really boring. So yeah, final question of this podcast, but not final question in the universe gratings. So I've had to limit the number of questions to ask from your informative episodes. Otherwise I'm pretty sure this would be a book. Thank you for doing that. I appreciate that, but I'm also glad you have so

many questions. That's a good thing. Listening to the Squid Games episode, which I can't watch because it's only in subtitles after Colossal Squid, I can only assume there would be a kraken. My question is, if there was a cephalopod capable of reaching such an extreme size, do you think it would resemble a squid appearance, octopus, octopus appearance, or a mixture of both. Your fan Dan, Well, thanks

fan Dan, So interesting question about cephalopod size. The short answer is that I believe squid is probably the most likely thing to reach crack in size. Now, would they reach crack in size, I'm not sure. Um, I suppose

it's possible. I would think though. It seems like the biggest animals in the sea are ones that breathe with lungs, like the blue whales, So blue whales have a couple of advantages for them in terms of getting too huge crack in size, and that is their lungs, because lung breathing is a lot more efficient than gills even if they are underwater, surprisingly like coming up to surface every forty minutes or hour or so to breathe and get in a huge amount of oxygen, and diving is surprisingly

more efficient than breathing water and extracting oxygen from water. So they have a lot of efficiency when it comes to getting enough oxygen through a massive body. And so I don't know if you would ever have a cephalopod that and does not have air breathing lungs to those proportions, but if you did, I would gets squid shape. And so first that is based on the current situation, which is octopuses tend to be smaller than squid and the

largest octopus is the giant Pacific octopus. And the absolute largest specimen of giant pacific octopus is ever known was thirty ft long and over six hundred pounds or nine meters and two d seventy which is wow, pretty big, pretty big, old squishy boy. This was a special individual though typically Pacific giant op Wow, giant pacific oct jeez, why am I pacific? No? Alright, I'm gonna get it this time, promise. Giant pacific octopus. Wow, I did that

Like a champ um. They are typically smaller, about half as long in a sixth of the weights, so that specimen I described that as absolutely massive. That was a unique individual. But because it did get that size, look,

then it means it's physically possible. So that seems pretty big. However, in comparison, one of the largest squid species in terms of heft is the colossal squid, which uh can weigh up to around one thousand, five hundred pounds and are over thirty three ft long, so that's six eight and ten meters, so yeah, pretty big boys. A giant squid specimen is actually the largest cephalopod recorded that I was

able to find um. Even though colossal squid tend to be heavier on average than the giant squid, uh, giant squid tend to be longer, and the largest squid recorded was a giant squid specimen, and this was over forty three ft or thirteen meters long and likely weighed around two thousand pounds or over nins, which yeah, it's pretty big. So why do squid get so much larger than octopuses? So I think likely their anatomy gives them a leg or I guess a tentacle up on being able to

get that big. So the way to get that big, uh, and the evolutionary pressures to get that big would be to be a deep deep sea creature, like really far down. And most octopuses are not necessarily well adapted for the deepest ocean, although there are some, and those that are, like the Dumbo octopus, have actually developed fins to allow them to move at low energy levels, where a lot of squid have fins. Now, this is key because both

octopuses and squid use jet propulsion to move. That's taking in water on through one siphon then farting it out and that makes them go forward. But squid also tend to have fins that will help them coast along on low amounts of energy, and so they can actually be more energy efficient in moving over longer distances. And this

is really important for the deep sea giant squid lifestyle. So, like I mentioned just a little bit ago, if you want a species to get real big in the ocean, usually you want to force him to go deeper in the ocean. I mean obviously over you know, evolution periods of time, Like you've got the giant is a pod, you've got the giant crabs, and these are deep sea creatures that to negate really huge. And why does this gigantism happen, Well, this is because the deep ocean is

sparse and nutrition. It's like a big desert, but the sand is water. And while you might think that you should be small so you don't need as much food, actually being small means you have a much more rapid metabolism. If a hummingbird or a tiny bat or a shrew just skips a few meals, they can die, whereas a larger animal like a bear can hibernate through long periods of time. And you know or or you know, like something like a big snake can eat a meal and

go for a long time in between meals. So being bigger can actually help you have a much slower metabolism. So even though you need more food to get that big, you can have a big meal and then a long break in between those meals. And so that's important if you're in a food dessert. Essentially where you may go a long time before seeing any food as long as like, once you see some food, you can get a good

amount of it. And because the squid are more hydrodynamic, they have those fin lined bodies and they can travel longer distances. They can have that sort of lifestyle of just sort of carefully casually drifting in this deep ocean, and then when they see a fish or even a smaller squid, they can eat it, uh and then go

a long period of time without eating again. Whereas octopuses tend not to I think, be as hydrodynamic, they are not as efficient and they don't aren't able, wouldn't be able to travel those long distances as efficiently as say in a squid type body shape. So that is why I think the kraken would probably be a squid. But if you want a kraken, uh, it would probably actually need to breathe oxygen, which currently suffle pods don't do.

So you oh, that's why I think whales tend to be the big ones that we find so whale sized cracking probably not, but you know, the biggest cephalopods are probably going to have that nice like um, you know, long distance train like body that the giants would have with the fins that helped them coast over long distances, so they can get a nice meal sort of just cruise for a while and then get another nice meal. So, hey, you know what, thank you so much for your questions.

I love them so much. They make me think and research and you know, really, I just really appreciate it and I love interacting with you guys. So hey, if you have a question, you can write to me a Creature feature pod act gmail dot com. I'll do the answer to to the guests who squawking thing next week and so look forward to that. Hey, you know what, thank you so much for listening. I really appreciate it. Uh. And also thanks to the Space Costics for their super

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