Who doesn’t like a good survivor story? Today, Laura and Katy talk about some species who have survived mass extinctions and remain relatively unchanged. These living fossils help us to imagine what our planet looked like millions of years ago and how evolution has changed things. They are the embodiment of the old adage, “if it ain’t broke, don’t fix it.”
Who doesn’t like a good survivor story? Today, Laura and Katy talk about some species who have survived mass extinctions and remain relatively unchanged. These living fossils help us to imagine what our planet looked like millions of years ago and how evolution has changed things. They are the embodiment of the old adage, “if it ain’t broke, don’t fix it.”
Hello and welcome to For The Love of Nature, a podcast where we tell you everything you needed to know about nature, and probably more than you wanted to know. I'm
Katy:Laura. And I'm Katie. And today we're gonna be talking about how several species live today are very similar to their prehistoric ancestors, aka a living fossils.
Laura:Yes. And I. Feel a little like a living fossil because we haven't had episodes for the last two weeks. We've just been Laura. I know it is all completely Well, it's my computer's fault. So it is, sorry everybody. Thank you for bearing with us. I really wanted to, but my computer crashed and everything we'd recorded was gone. So, Laura, everything, her lesson that immediately after recording, I will be uploading these files to the drive so that they're not lost forever into the ether.
Katy:What's funny is like normally you are the one that uploads everything first, and I'm always the one strangling behind. And this time I was the one that was like, boom. Gonna have it up. Yep. And yep,
Laura:yep, yep, yep, yep, yep. So here we are. But now that the computer is fixed and I can edit things again cuz I couldn't edit, I have a laptop, but it's a like a Chromebook, so it doesn't have. Like anything?
Katy:Anything, yeah.
Laura:Yeah. Specific for Microsoft, I couldn't use the Yeti, like I couldn't, so we just held off. Now you can hear good quality audio, hopefully as we crisp, just crisp, um, as we talk about living fossils. All right so let's get started, I guess. So really quick before we dive into, you know, Katie and I are doing the normal thing where we each chose two different living fossil species. I wanna talk about what is a living fossil. So I didn't know that Darwin coined the term. Hmm. but he did, and he said it's that a spec, it's a species or group of species that has remained so little change that it provides an insight into earlier, now extinct forms of life. But he did say it was a fanciful term. Ear
Katy:quotes, fanciful
Laura:It's because really it does have no clear, measurable
Katy:definition. Yeah. What do you include that, do you, is it just your older best friend or is it, yeah, you know,
Laura:In actual. Yeah. Well, some people focus on the different parts of it. Some people focus on the fact that it's like an evolutionary relic. Yeah. Some peop, some people focus on the part where it's a little changed through time, and then some people talk about it in terms of Lazarus taxa, which is ones that people thought were extinct but actually aren't. So it just means different things to different.
Katy:of course, because it's science and so nothing is consistent. Yes. You know, everything has to be way more complicated than what it needs to be.
Laura:Well, right. And because it's science, we're always learning new things. Yeah. And species are always, always changing. So it's a very relative ever-changing term because evolution is always happening, even if it's just little tiny bits. So nothing is the exact same as when it first started
Katy:ever
Laura:But these ones. In comparison to other things haven't changed as much. And actually I did find a study done that they developed a proposed evolutionary performance index. What? Which basically, yeah, it basically means that they looked at the number of species within the clay or like within that, you know, what's like, uh, what's the cla? It's not one of the it's one of, it's not one of the levels. It's more of like
Katy:a, a grouping of Yeah, yeah. Grouping of.
Laura:And it looks at how long that group's been around and then the relative number of changes since they first appeared. And then that number, after putting all of that together is the evolutionary performance index. So that tells you if it's technically a living fossil is a crazy, I really
Katy:calculations, I really just need to coin a random term. Oh, make a sturdy definition And just be like, this is what it is. Do it.
Laura:And, and you put it quite, I put it on Urban Dictionary. You did put it in Urban
Katy:Dictionary. What did we say? S ss p D.
Laura:Oh yeah. I suffered from spd, suppress, pulp, dancing, only. A lot of times it does just come out. I'm not really that suppressed.
Katy:only a little suppressed. It's fine. Only, only a bit. Uh, All right. What do you want me to do? You wanna go first? Sure. Okay.
Laura:Uh, okay. So what is one of those ones that hasn't changed very much. The two atara. Ooh, that's a good one. Yeah. So a lot of people I think have never even heard of Atu Atara. So it is a little bit of natural history. First, the Tu Atara, that name is actually Mai for peaks on back or spiny back. Okay. Sorry.
Katy:Cause they have spines on their back. Okay. But I was for, okay, listen, you guys know I drink whenever we record these. And so for a second I was like, peaks, like peak, like a peekaboo, like peaks on. I peek at their back. I peek at their back. No, spiny back spines. P e a k We're good? Yes,
Laura:good. They live on 32 to 37 small New Zealand islands in Buroughs, which is really cute to think of them peeking out. And they look like lizards, but they're not, they are reptile, so they're related to lizards, crocodiles, turtles, and snakes. But they're their own thing. They're olive green to brown to even an orange and red. with spines down their back, sort of like an iguana. And the males are about 20 to 31 inches long and about one to three pounds. So they're
Katy:not as cute peeking out of a burrow as you would expect
Laura:But they are kind of cute. I would, they are, their faces are cute. They're not lizards. Yeah. But yeah, they've got like really big dark eyes And they do look a lot like an guana I think. Yeah,
Katy:they do. No, they definitely.
Laura:So they eat mostly invertebrates, but also eggs, chicks, other lizards, and even their own babies, other baby to atara. So it's brutal Um, but what's really cool, well, there's a couple of cool things about Tu Atara. One is that they can be active in cool weather, and for anybody who knows much about reptiles, you know that they are cold blooded, so they're whatever temperature it is outside. So they have to use the. To stay warm and they have to be warm to be active. But two atara live in a place and that is not that warm. And so they have developed or they've adapted to be able to deal with those cooler temperatures. Their body is typically below 72 degrees Fahrenheit and can go down to 55 degrees Fahrenheit. With them still being able to run around and do things.
Katy:Yeah. I feel like that's not fair to other reptiles. Yeah.
Laura:Right. Because at 55, most of the guys around here are asleep, dead. Um,
Katy:70 actually dead, but you
Laura:know, like Roomating or Yes. You know, lizard or, uh, reptile form of hibernating. So yeah, they can just deal with the cold. No problem. They also, which helps them because they're nocturnal and it's even colder at. And they have a third eye on top of their head that's believed to be able to sense light, which triggers hormones, aka, or circadian rhythm, which, you
Katy:know, I don't think I knew that. What the third eye or the circadian rhythm? Yeah. Nope. The third eye Okay. No circadian rhythm. I'm very familiar with it because mine sucks. So yeah.
Laura:but no, yeah, they do, they have a third eye on top of their head, and right now it's just like a, you. you can't see it unless they're a baby. And then you can see it and then that gets darker, like the scale over top of it, darkens, and you can't see anything. But when they're a baby, you can. But unlike some other animals who have like weird light sensing eyes that don't function for anything else, this one has a lens, a cornea, and a primitive. Which definitely points to the fact that it probably was once a functioning eye. Yeah. Like a real eyeball. Like a real eyeball on top of their head. Interesting. But I mean, they live on an island, we're probably with lots of seabirds, so having an eye on top of your head would probably be worse. Huge.
Katy:Just poop right in the eye. But at the same time, I mean, I could see how it would evolve because you always wanna be. Oh,
Laura:know what? Yeah, right. Depth from above. Yeah.
Katy:Like, but yeah. And then that eye just always gets pecked out. Like,
oh
Laura:geez, I was thinking poop, not peck,
Katy:Hi.
Laura:This is like our flex an eye out. This
Katy:is like our, uh, could you survive that episode all over again where you, you just
Laura:take the innocent rock mind, the light away, and yeah. Really.
Katy:Somebody needs some, someone or something needs to die immediately. like it's every time
Laura:just choke out a swan.
Katy:I'm gonna start laughing. You guys haven't listened to that episode. What was that season like? Two or three? I can't remember. And it was. Well, could you It was one of the could yous. Yeah. Could you fight that? That's what it was. Fight that it was, could you fight that? I, man, I still, Hey, it went dark. Just be ready. Every, everything, because one was like, I think the one was the swamp, where you were just gonna like, kind of bat it away. And I'm like, no, you grab its neck, pull it out of the water, drown
Laura:it. Intense.
Katy:Anyway. Two ats, two
Laura:atara. Um, they their sex can be determined by temperature, like a lot of different reptiles, but that's a big problem for them because of climate change. So as temperatures get warmer, that means less baby boy to atara are gonna be born. So scientists are already starting to pull eggs to make sure that doesn't happen. and they can live anywhere from 60 to a hundred plus years, which is a really long time. Yeah. I don't think I knew that. Yeah, I definitely didn't. Dang, that's, I mean, way longer than lizards. Yeah. Most snakes and everything about them is just slow. So yes, they're living that long, but that's they grow for 35 years. Yeah. So then I got grown up until then. They don't read sexual maturity until they're 10 years old, which is really late in the game. Yeah. Females only produce every two to five years, which is like, what are you, wait, like
Katy:what? Get on it, girl. Come on now. This is your only purpose. Yeah.
Laura:And not to be
Katy:harsh, but that's, yeah. That's a duar way. I mean, come.
Laura:We just don't know. There's actually a lot more to what's going on. They're like, they're all
Katy:jobs. Yeah. Business jobs.
Laura:And their incubation of their eggs is 12 to 15 months, which is so holy crap.
Katy:Yeah, that is, that is very long.
Laura:So I mean, yeah I guess that would make it at least every two years. still though.
Katy:Why? Why? I mean, is it? Is it because it's so cold that it like slows down the development because maybe, dang, somebody's gotta cook those eggs faster from
Laura:here, Well, right, and I don't think they're sitting on them. Yeah. Oh, geez. It's also really, really, really risky because you're just leaving your babies like they're in a borough. But
Katy:still for 12 to 15 months, that's, yeah. That's a lot of anxiety for that mom. Yeah. Oh, totally. Right. For how long they lived. That's a lot of anxiety. My just having a fetus
Laura:outside of your body for 12 to 15 months trying to make sure that she doesn't die. Listen,
Katy:we're not gonna talk about our. Our baby. Yeah. Because they're gonna have another baby fuse of the nipple episode. Yeah. Our, our marsupial
Laura:talk. Yeah. So yeah, these, uh, two Taras are protected because they are in big trouble. They only live on these few islands. They used to live on the mainland, and
Katy:then these stupid island
Laura:animals, man, they're just not, they weren't ready for the predator. They introduced predators. Rats were really their downfall. They can live only where a rat cannot swim.
Katy:Which is, could you measure away on the
Laura:mainland? This episode is just constant throw aback to other episodes. I know, right? So that's a little bit in the natural history. Real quick, why is it a living fossil? The whole point of this episode,
Katy:everything you just said.
Laura:Um, yeah. Well the, there's more to it like, yeah, sure they're cool at lizards, but that's not really like why they're living Fossil. One reason is that they're the only species. in their order that's left. So
Katy:yeah. I guess they should probably survive, you know, important for them.
Laura:They're, they're it, yeah. Yeah. So Rinka sepia that's the order. There used to be a ton of them in the Jurassic period before the dinosaurs. Hmm. So, you know, we think of Jurassic Park as being like Prime Dino time, but not at the beginning of the Jurassic. They used to also, or they seemed to be a pretty. order, and some of them were very, very specialized to certain niches. They all died. Now it's just this modern to atara left. Most other of the species, one extinct about 60 million years ago, close to at the close of the Mesozoic, probably because it was outcompeted by lizards, snakes, crocodiles, and even other dinosaurs. There's not a lot of fossil record for the tu atara. This is just wild.
Katy:Yeah, because can you, ima okay. Just finding a fossil in general is, is right. So ha. Like
Laura:unique this episode.
Katy:Yeah.
Laura:Explain how fossils
Katy:are made but it's just so difficult. And then to find a little too atara a fossil. I mean, that's just like a whole
Laura:other level. Well, I'm trying to connect the dots too, of the Yeah. You know, because, 60 million years ago, most died, so they've been along around longer. So yes, there's not a lot of fossil record. However, scientists have recently found a new species in the fossil record when they were going through a backlog of stuff at Harvard. It was literally in a drawer. at Harvard since 1982 that had just not been looked at in catalog. That's how backed up they are.
Katy:I would be if I was that original. Do they know who originally discovered it? I don't know that because I would be, I would be so mad livid to be that original person to have discovered that it's
Laura:been what? 40 something years.
Katy:Yeah, you'll, you might even, I told you, yeah, I told you guys back then. This was a thing. Nobody listens to me. You know, it's just been sitting in a drawer.
Laura:So Yeah, they're just like looking through it. They use CT scans as statistical modeling and connected it to the modern totara. So there was the link that they'd been looking for this whole
Katy:time in, in Harvard. Geez, story of my
Laura:life though. I'm always losing things, but to be fair, I know they exist.
Katy:Yeah. But that's the hard part for me is like, I know they exist. I just can't find it. I'd be like, I swear there was a fossil around here somewhere that I, it didn't, could be the missing
Laura:link and I'll never find it. I'll never find it. Or 40 years.
Katy:That dude you don't even know how, how true that is for me. Like I know I, because of my adhd, I just lose everything. And then I like, and poor Luke, like my son is the same way. So I, when I have him on the weekends, I cannot tell you how much of our conversations are made up with. Where did I put this from? Both of us. Where did I put this? Yeah, I don't know. Where did you put it? I don't know. It's just like the whole weekend of us. I don't know where we put it. That would be us. Good
Laura:grief. So the fossil showed that the body plan hasn't changed much in almost 190 million years. So she's the, I actually took the quote from this article because it said, researchers argue this lack of change may represent natural selection on over. Slow rates of evolution don't necessarily mean absence of evolution, and basically it's the evolutionary equivalent of the A Dodge. If it ain't broke, don't fix it. I, and that's fair. That's really what all of these living fossils are like. Yeah, it worked. Why change?
Katy:Yeah. So it's just everything else is like growing appendages and everything, and these guys are like, you know what? I think what I have is working right now. Let's just, let's just. and,
Laura:It, the Tuit Tower also has a really primitive heart, even compared to other reptiles, which already have pretty primitive circulatory systems compared to us. And their brain str structure and the posture of where it is in the skull is like mm-hmm. ancestors of other reptiles. So we're talking like, oh, weird. This is maybe like the first reptile. Yeah. Could have been the first one type of. And then last, but not least, funnily enough, although they may not have changed based on how sluggish their metabolism is and how it takes forever for them to grow up and. They actually do have the fastest sperm of any reptile.
Katy:Oh, they got something going for'em then
Laura:Yeah. It's actually four times faster. And I feel like this is a case of, you know, they peaked too early. They burnt themselves out. Like they, they burnt themselves out just getting to the egg and then you're right. The rest of their life they were like, eff it. Yeah,
Katy:I did my work. I did, I did the hard part and I'm done. And the
Laura:reason it's so fast is probably because they don't have a. So that little, that would do it extra
Katy:hard to get there. That would do it. Yeah.
Laura:And that's Atu Atara Full Living Fossil that nobody really knows about.
Katy:Yeah. I feel like that's definitely, that would definitely be for me, I believe the Hallmark animal. that you could use to question people, to divide between who is an animal person and who is not an animal person. Yeah. I, you know,
Laura:who that or the Sicilians like, yes. When you're talking about amphibians, yes. Because everyone skips over them too.
Katy:Yes. I feel like that is how you would divide. Like, if somebody's like, oh yeah, I like animals. You can figure out, you know, if they say that just because they like,
Laura:like dogs, or even if they, they like reptiles, but then forget about this entire, entire
Katy:group of it. Yeah. Nope. Two ATARs. They're cool. All right. Well, the first Living Fossil that I'm gonna talk about is one of my favorite animals. Don't think I've talked exclusively about them yet, but I think we've hit on'em quite a few times. And it's crocodiles. Yeah.
Laura:Yeah. I feel, mm, we talked about, yeah. I think in passing you talked about something with like mating with crocodiles. I'm pretty
Katy:sure. I don't remember. Again, this is a. Or a good problem to have whenever we like, have done so many. We're like, I don't remember. Yeah. So,
Laura:yeah. Yeah. I mean, I'm always willing to hear more about crocodiles, so
Katy:let's go because they are really freaking cool. Yeah. So let's go over just be public. PSA from, for the love of nature is the differences between crocodiles and alligators, since they are commonly confused. All right. crocodiles and alligators are often mistaken for each other, but they do have distinguishing physical features that set them apart. First, let me just say, if you are close enough to be able to really tell these, you're too, you're too close. Unless you're looking through some binos you're too close. One of the easiest ways though, to tell them apart is just geographically. The only place where they're naturally found together is South Florida. Even unnaturally together is Florida. You know, cuz it's just like a cess. Animals down there, things that don't belong. Yeah, yeah, yeah. But that, but in this case it is natural. Yeah. This case it is natural. So crocodiles can be found in several regions around the world, including Africa, Asia, Australia, and the Americas. They inhabit a diverse ecosystem from freshwater rivers to lakes, to end lakes blah, to saltwater estuaries and mangrove swamps. So they are pretty, pretty diverse. some species know, like for instance, the American crocodile can even be found in completely open ocean waters, which is so freaking terrifying. Salty. Yeah. But it's also so salty, like,
Laura:like for a crocodile is so salty. Or the
Katy:I immediately like, he's, he's just like sassy, just like salty about Yes. As this woman meant a lot. I'm just like, I mean, that would be, that would be a, a Graco. I would just angry. but no, like just the water for like a, a reptile to live out there. Because you know how you have the iguanas down the Galapagos, I think it is. They're always like spitting the salt out their noses and everything. I mean, I feel like that would be the same, just so salty anyway. Crocodiles though, they have the V-shaped snout and the ability to tolerate salt water. Like I said, while alligators have a U-shape snout and are typically found in freshwater habitats, and yes, it's a V and a U, but I would say more it's. The Crocs have a longer skinnier snout. And the alligators more look like they ran into a wall. Yeah. Yeah.
Laura:Like they got a real big snoop.
Katy:Yes to
Laura:not to the crocodiles. Yeah, it's, yeah. To not boo
Katy:Uh, they are really cute. They won again. One of my favorite animals crocodiles are renowned for their enormous size and weight with some species measuring up to 23 feet in length. Oh my gosh. Yeah. And it's a monster and weighing over 2000 pounds. This is dragon. It's a ribbon dragon. It is, it is. When I was in Australia, I saw. Like there's a difference between like in the zoo seeing saltwater crocodiles and then in
Laura:the wild Well wait, cause there's still not 23 feet even in the zoo. Yeah, usually. I've never seen
Katy:one that big. No. But then just seeing it in the wild next to like normal things, you know what I mean? Like the, like a guardrail. Cuz that was one of'em. I was like, holy crap, that thing is huge. Cuz we were on a, like a little bridge and it was down below us and it was up near like sunbath. near the side of the road and there was like the guardrail there, like a typical like metal guardrail. And I was like, that's ginormous cuz you could just tell the proportions. Yeah. Yeah. They're huge. No thank you.
Laura:That I wanna, and they like, because they're covered in scales that look like armor. They just are like a. Straight up tank.
Katy:No, they are. They so are and it's those scales that protect them from everything. They prevent infections and they also ate and retaining moisture in dry environments. Crocodiles have strong inlaws long jaws that are used for catching and killing prey. Their eyes and nostrils are located on the top of their heads, which I think everybody knows that enabling them to see and breathe. Partially submerged. So that's just a little bit of natural history. Now let's go into their living fossils. Crocodile. Yeah, CRO. There's my word. There's my word that I'm, oh,
Laura:yeah. There you go. Fossils.
Katy:Fossils. How fossil is it? Mm. I'm gonna make a scale and I'll let you know how fastly that fossil. Foist Oh, geez. Uh, all right. Crocodiles are very much so referred to as Living Fossil. I think this is definitely some of the ones that whenever people are like, oh, living fossil crocodiles.
Laura:Yeah, yeah. They're everybody who sees one or like, that's a
Katy:dinosaur's. Yeah. That's, and it's in so many book intros or anything like the crocodile, the living. All the time. And that's because like Laura said, just like the two atara, they have changed very little over millions of years now. The oldest living reptile living fossil is the tu atara. Like what Laura went o uh, went over. But the oldest living reptile by age is a tortoise named Jonathan.
Laura:That is the most random
Katy:Right. Thing that to just add in. Well, because it was the, because I typed in the oldest reptile, which Yeah. As a human, I should have known what that was going to give me. Yeah. What I meant was, you know, lineage. Right. What I got was a tortoise named Jonathan Yeah. Who was hatched and they believe 1832. So he's about 191. Yeah. Which again, I feel like 191 years old is a bit excessive.
Laura:Living. Strong. Go
Katy:Jonathan. and he's last I heard he's still making babies. Yeah. So I mean, yeah, he's doing just fine. So crocodiles are though, as far as lineage goes back, they are one of the oldest living reptiles that we have. The first fossil of a crocodile was discovered in the early 18 hundreds in the United States. In 1822, a partial crocodile skeleton went unearthed in New Jersey and. Tele OSAs, making it the first crocodile fossil to be identified and classified. However, as always, with science, tele OSAs was later discovered to be a misidentification and it was actually a fossil of a prehistoric marine reptile called the i Theo Source. So like, you know what? Nope, that's not a crocodile. Again, how they know with the few. Beyond me, but it was a misidentification. But for that year, that whole first year, like year or so, they're like, this is a crocodile. And then for whatever freaking weird reason, the next year, whenever the chances Yeah. Is whenever they recognized a crocodile fossil in 1823 and England by Gish names William Buckland. And that fossil was found in stones. Uh, Oxfordshire and was initially to believe to be a type of lizard. However, Bucklin later realized that it was previously unknown species of C crocodile and named it Teleo sos Caius. So they're like, isn't the same thing. Yeah, this is the same thing. We're just gonna add another word to it. It's fine guys. But I don't know when Buckland, cuz that's when. 1823 is like when he actually discovered it, but I don't know when he figured out that it wasn't a lizard. Gotcha. And that it was a cro. You know what I mean? So I think that was like, yeah, a little later. Yeah, sometime afterwards. But since then, numerous fossils of crocodiles and their prehistoric relatives have been found all over the world providing very valuable insights in the evolution and history of these ancient creatures. Did they, do,
Laura:you know, did you read anything about, did alligators come from crocodiles or did they. Simultaneously from a common
Katy:ancestor? I didn't see that, but I'm, I was just curious. It just occurred to me, I wanna say that I, it's gotta be simultaneous, you know what I mean? Like, like you both have a common ancestor. Yeah, they have a common ancestor, but I don't know. I'd have to look. That's completely a guess. But the fossils, they do continue to be a subjective interest for scientists and researchers who seek to better understand their past and present. Cuz again, to understand, you know, where these possibly are going and habitat, all that kind of stuff, we need to understand the history in the past. So what makes Crocodile Evolution so unique? Again, as Laura touched on, it's really the lack of evolution that makes them really unique. Study has sh has shown that crocodile shared numerous physical characteristics with their ancient ancestors, including the Ford Chambered heart, a tough skin that provides protection against injury and affection, and a powerful tale for swimming. And if you guys haven't seen like. There are some gnarly crocodile and alligator injuries out there that are just so gross. Like half jaws hanging off and they're like, no, I'm fine guys. Yeah, I like,
Laura:I saw a video of one getting hiss arm bit off by another one and it was not
Katy:even that phased. No. It's just like, oh goodness, there it goes. Okay, let's just continue on with my day. Like just whatever. But apparently, I mean, that was pretty much how they were then too. Like just tough and scaly and could just. Hit, I guess. But these traits have enabled crocodiles to survive and thrive in a variety of environments over millions of years compared to other species. Crocodiles have undergone relatively slow evolution, which has contributed to their statuses of living Fossil. One research article published in the Proceedings of the National Academy of Sciences discovered that crocodiles have a slow rate of evolution, which contributes to their living fossil status. So basically somebody just did research on them being fossils and. This is a thing again, why I am not published. Don't know. While publishing these scientific journals. Anyway the researchers analyzed the genomes of crocodiles and discovered that over the past 250 million years, their genetic makeup has changed very little. The gradual rate of evolution has allowed crocodiles to maintain their physical traits and adapt to changing environments over time because you gotta figure over 250 million years how our planet has changed. It. That's, and they're still, they're still kicking. It's fine. Yeah, it's fine, man. That's just crazy. So anyway, the study offers fresh insights in the evolutionary history of crocodiles and explains why they've thrived and survived so long. Just looking at the genomes, cuz it, again, it wasn't broke, so they decided not to fix it. Crocodiles are also recognized for their unusual behaviors, which have helped them to survive over millions of years. For examples, crocodiles have an impressive ability to regulate their body temperature by sun bathing or cooling off in water. They also have a distinctive way of breathing that allows'em to stand a water for extended periods of time, and they're capable of detecting prey from long distances using their senses. Cool. Yep. So anyway, so again, they weren't broke, they didn't fix it, and they're just chill. Crocodile. Just chilling. Chilling. Crocs. Yeah. I almost got a crocodile tattoo when I was in Australia. I didn't, but I almost did. Fun story, right? The end scene Well, because what I really wanted is I wanted like a footprint be, but I couldn't like how the heck do you do like a, yeah. You know what I mean? Like how do you
Laura:But yes, do that. Do the footprint. So cool. When I was in Costa Rica, it's so cool you saw him on the beach and it looked
Katy:like a dragon had just came from It does. It looks sweet. Yeah.
Laura:Okay, well, something else Aquatic is my last guy or gal, and it's the horseshoe crab. I feel like I had to do them for several reasons. One, I live in Maryland and horseshoe in you can find them all through the Chesapeake. But also I grew. Loving horseshoe crabs. When we would go to shin aig. They're everywhere. Every summer. Yeah. We'd go, they have'em in like the nature center's little touch tank. I was never afraid of them. No. I always thought they're really cool. Yeah. So for those of you that aren't familiar with horseshoe crabs, here's a little bit of natural history. Okay, so, important note. They are in fact not crabs, So let's just
Katy:start there. Freaking scientists strike again.
Laura:they are actually related to spiders and other arachnoid. They're not a spider or interacted, but they're a close relative.
Katy:Yeah. Closer. Closer than being a crab. Right.
Laura:right. Which, yeah. Nope, nope. There are four different species, which I didn't know. I just figured there's one horseshoe crab all around the world, which is silly. I don't know why I thought that. But there are three other species, one here in the Americas, and then three more over in near
Katy:Asia. Okay. So it's
Laura:okay. Yeah. Just not in this part of the
Katy:same, the same ocean. Again though, I just, I mean, I never thought about there being multiple, but again, I, I don't waste a whole lot of brain energy thinking about the dax of the horseshoe crap. That's very true. Yeah. and all my spare time I have, I wonder if
Laura:there are more horseshoe crabs out there. Yeah. Right. Yeah. So what did they look like? They do kind of look like a crab, but,
Katy:but alien like, yeah.
Laura:Yeah. So they have an exoskeleton. They're brownish in color. They have 10 legs and their body's divided into three segments. The head roughly does resemble the shape of a horseshoe, so it's just like a. Half circle kind of thing.
Katy:Yeah. I was like, I mean, kind
Laura:of. Yeah, yeah, yeah, yeah. They're, the middle part is barely visible. Yeah. Or it's like just a tiny little triangle piece, and then the tail is really long and pointy. They
Katy:get pretty big, right?
Laura:Yeah. Decent size. 14, 19 inches depending
Katy:on the sex. Because I was gonna say, I've seen some pretty, pretty big ones. Ones, yeah. Yeah.
Laura:And the females are,
Katy:I mean, to be fair, most of the ones I've seen are dead, but, you know. Yeah. Yeah. Because they get washed. The old ones get washed up, wash up.
Laura:What I had no idea about is that they have nine eyes and a few light receptors on their, near their tail. Yeah.
Katy:Nailed. Like on the tail or like
Laura:Yeah, like interesting. Okay. Some receptor things. So they have two cing eyes. Okay. They're compounded. What is up by
Katy:you finding all these animals with extra eyes? I know it was an
Laura:accident. theme of the day. Um, so they have two seeing eyes and then they have a couple more spreader out, spread out around and that are extremely sensitive to light, but not being able to see. And even the ones that can. don't have great vision but they're again, just extremely sensitive to light. They actually have the largest rods and cones of any animal. Huh. Yeah, but they are very dependent on like the moon and, you know, being under water. The light really matters to them. They're, they come out to breed at nighttime, and it depends on whether it's a new moon or a full moon or all that
Katy:stuff. They're really into their astrology and their signs. They're signs, they're down there. I'm a Virgo. What are you again? Yeah,
Laura:they're, they would, you would think they would all be cancers, but they're They should be,
Katy:yeah. Yeah.
Laura:false. They all the species live Levon coastlines and some are keystone species.
Katy:Meaning that they, wait, did you already say, are they all salt?
Laura:Coastline. I guess they at least have to be
Katy:brackish. Yeah, I'll look it up. Good. Keep talking.
Laura:Okay. Keystone species. So for anyone who has not heard that term before, it is one that many other species rely on for their health. So it, they are a key to the area. They also eat worms, mollusks, crustaceans, fish and algae,
Katy:or mine. It doesn't look like there are any freshwater horseshoe
Laura:crabs. Okay, so here's where things get kind of mind blowing. So the females lay about a hundred thousand eggs every. Okay. That is a ton. And one of the reasons why they're a keystone species because a lot of birds eat their eggs. Okay, I need to think. Okay. With the species, with ling, you know, like a hundred thousand eggs, surely the horseshoe crabs are doing well. Well, the one issue is that they can't breed until they're about 10 years old, which she's way late in the game. Especially when you're only living to be about 20 So that's like us not being able to breed until we're like 35.
Katy:Couldn't, it's pretty late I just couldn't, couldn't, sorry, couldn't.
Laura:But even. more mind blowing and is that okay? Yes, they lay a hundred thousand eggs every year, but scientists estimate that less than three of those a hundred thousand live more than one year.
Katy:Okay, so here we go. Speaking from an evolution standpoint, you would think that they would've had that figured out by now, you know what I mean? Or like they had to a different strategy like something else. Rental repair. Okay.
Laura:Cuz something is not working. I mean, yeah, they've got the numbers, thankfully. So the, you know, less than three. and then that's just one year. They have to make it till they're 10. Yeah. Before they can start having babies. So let, that's probably what, one, one of a hundred thousand makes to reproduction That's
Katy:crazy. Yeah, that's, that just doesn't seem
Laura:fair. No, not at all. And That alone makes them not, you know, I mean, yes, there is a lot of horseshoe crabs, but again, they're just playing the numbers game. If they make between 10 and 20 years old, that's 10 years worth of eggs. That means probably only 10 of your babies are gonna make it.
Katy:Still, though, you would think after all these years of evolution, they would have something else figured out. You know what I mean? Yeah. But no, but no. Like figure, figure something else out.
Laura:And so that's their own like issues f right? That's their own issues. But then of course people have to make it worse for them because I'm, I, so we've mentioned in a previous episode, I can't remember which one, but in some nature news, I talked about horseshoe crabs, insane blue blood. Oh, yeah, yeah, yeah, yeah. And how it's used in biomedical testing. Long story short, we use horseshoe crab blood to test biomedical instruments in order to make sure that there's nothing on. like bacteria wise before they're bagged up and sent out and well sterilized one more time and then packaged up. So without horseshoe crabs, blood, we wouldn't have any testing of like scalpels and all that stuff.
Katy:Right. Which is just crazy. So we need their demise to have our life. Yeah. Yeah. So we gather,
Laura:I mean, they're harvested. I mean, so many are harvested. Thankfully, we're not killing them right away. We're not killing them right off. What you do is you bleed like 30% of their blood and
Katy:you know, just, we don't kill'em off right away. What we do, we just take 30% of your blood Here's if somebody said that to me, I can't even, I can't even take like five vials of blood without me like passing out. Can you imagine? Like, take, listen
Laura:Katie, it's gonna be fine. They're gonna be, you're gonna live, we're just gonna take 30% of. and which you can survive. Yeah. And then we're just gonna throw you back outside in the water. You're gonna feel like garbage, but it's gonna be fine.
Katy:Yeah, you'll be fine. You're very cooped, so, okay.
Laura:Needless to say, yes, a lot of them are okay, but a lot of them are also not okay after losing that much blood and then they just don't eaten. Why? Geez. Although, can you imagine the predator that eats them, being like, why are they so dry?
Katy:She was like, fuck, Forgot the sauce or something.
Laura:That's what's up. When you gonna, it's like when you go to Taco Bell and you get not a filled. Let me just tell you right now how triggered I get when I get a crunch wrap Supreme and it is flat A knot fall. that would be me. That's the predator heating the horseshoe crab.
Katy:What the heck is this crap?
Laura:Okay. Um, so because of all of this, I, the I U C N which is the organization who classifies how endangered an animal is, they list them as vulnerable, not endangered, but the step right beforehand. So real quick, why are they a living fossil? Because they've been around for 450 million years. All right. The oldest of the old, they have two main lineages. One is extinct and one is still around, which is crazy because a lot of the animals that we consider living fossils, they're a modern species. Yeah. Yeah. They are not, their species was not around. The horseshoe crab species, what, like their lineage was still around. They've still made it. There used to be 110 different species. Now there's only four. There is an online pictorial atlas of living and fossilized horseshoe crabs. So if you are interested at all in learning more about these creatures and their lineage, look'em up. They've got awesome pictures. Some of them looked crazy. They were very specialized. Hold please, what's. The, it's a pictorial atlas of living and fossilized. and then their scientific thing, which is zfa X I P H O S U R A. Okay, so a 310 million year old fossil was discovered that showed soft tissue, which is really rare. Listeners, if you've listened to a fossil episode, you'll know the process of fossilization does not usually save soft tissue. Typically, the only way that happens is with Amber like when insects get caught. However, that's not the case here. It actually just happened to be that whatever like rock and mineral, this horseshoe crab died in. Yeah, we got lucky. it. Yeah, the, there's another mineral. It actually surrounded the soft tissue and hardened. Then another mineral came in that's a darker color filled in that cavity. Once the soft tissue rotted away and then lifted a perfect, basically photo image of what the horseshoe crab's brain structure looked. And they could see that's really the way they knew that what they were looking at was a horseshoe crab, because it's brain structure looks exactly the same. They're crazy. Very little change in 310 million years. Some used to look very different. Like one of'em just looked like a pickax, like just the head of an, of a pickax.
Katy:I've seen that one. Yeah. Yeah, yeah, yeah.
Laura:But, Th that was a long, long time ago. Yes. In the past 150 million years. Still, still a long, you know, definitely speaking. A long, ongoing time ago. Yeah. No really only the size has changed since then. They figured out the body plan by one has gotten hundred
Katy:50 million years ago. Has it gotten bigger or smaller? Smaller, uh,
Laura:bigger, I think. Okay. Um, there were some that were only a couple inches, that was Oh, geez. How big they used to be. And then lastly, they've survived four freaking mass extinctions. True. Yeah. Okay. They survived. The dinosaur asked. Right. And they've just survived three other
Katy:things that kill figured most because they're, they are like, I mean, very much, they're like a crocodile. They're just like little tanks. So they probably just chilling in the bottle. The water. They're helmet, they're
Laura:upside down.
Katy:Helmet just hanging out. Sheltered. Yeah. Sheltered in place. Yeah. And guys, if we just stay right here, be fine. enough. They were,
Laura:after reading all of this, I got a. where I got really angry and sad and then sad uhoh because I was thinking it would be some real BS if it was us. That made them go extinct. Right? No. Right after them living through four, four mass extinctions, an asteroid. They survived an asteroid,
Katy:but humans ended them. Humans draining them with their bun,
Laura:like vampires. Yeah. Poor things. Yeah. Can you imagine being taken by an alien species and bled and then just thrown.
Katy:I mean, yeah. I mean I guess people do claim that that happens to, to them. Yeah. So butt stuff and then throw'em back under earth. there's still that mug. I think I sent it to you that says, get in losers. We're doing butt stuff and it's just this guy get in like spaceship. Yeah. Get governor spaceship, get in loser. We're doing butt stuff. makes me laugh every time. so good. And that's the word. All righty. Right. Well, the last one that I wanted to cover was the lunga fish. Ooh. So these are one of the ones, um, I don't know how to describe it. Not They're freaky. They are freaky. They are freaky. Yeah. They're freaky. Not like a weird, not as gross as like a lamprey or a. the hagfish that I talked about the other day. Yeah. Which is so disgusting. I don't think these ones are cute anyway. These ancient fish that are unique in many ways, including their ability to breathe there, their low reproductive rate, and their amazing ability to survive in harsh environments. The reproductive rate of lung fish is relatively low compared to other fish species. Females typically lay only a few dozen eggs at a time, which is much lower than other fish species that can lay, of course, thousands of eggs at a time. Additionally, lungfish have a long gestation period with some species taking up to five months to hatch. Okay, so here's the thing. So many of these ones, I mean, we're knocking'em for being like, Hey, you know, the risk that you're gonna take, but they've made it, but they've made it so like clearly there's something. Yeah. s forget hiding your baby. Stick'em out for the predators, like just There's some, there's clearly something to it. But that low reproductive rate is believed to be an adaptation to their harsh and unpredictable environment where the sources are. Where resources are limited in survival was difficult. By producing fewer offspring, lung fish can invest more energy into each individual offspring, increasing their chances of survival. So for the lung fish, that is how they did fewer so they can actually take care of'em, which again is weird for a fish. I was
Laura:gonna say, what does that even look like?
Katy:I don't, I don't know. They just coming around. Yeah, I think so. And then, I, I mean I don't think they're like regurgitating food and stuff, but I mean, you never know cause there are some species that do that. Lung fish can be found in Africa, south America and Australia and are known for their large size. Okay. So I always thought that lung fish were like relatively small. I don't know where I got that stuck on my head, but like I always thought like a foot or so in length. I've never even thought about a long fish. Not the case at all. The six different current lung fish. Most species grow to a fairly big size. The Australian lung fish may weigh up to 22 pounds, grow to a length of four feet. There's a south American species that reaches about also four feet, and then the largest one, which is the yellow mar. E or yellow marbled Ethiopian species. It's the largest and it can grow to just under seven feet. Whoa. That's
Laura:freaking huge. Yeah. Which is really big. And like they've got like little legs they
Katy:walk on. Yes. So that's what I'm saying, like that along the river. Yeah. But of course they're like, they're not like legs. They're like appendages. So, so it's like hobbling, like a quasimoto, like, you know what I mean? Like, not even like a good walk not like a lizard, like a wobble. I don't know why I thought that they were always just so small, but no, they can be fairly large. One of the most fascinating facts about lung fish, of course, is their ability to breathe air. While most fish extract oxygen from water through their gills, lung fish have specialized air breathing organ that allows'em to extract oxygen directly from the air. This adaptation is believed to have evolved in the Devo period over 370 million years ago, making one. Again, one of the oldest fish groups in existence. And this too, I mean, you figure is like sediments and things like that whenever we're talking about like harsh environments. Or like TAs. Yeah, like low dissolved oxygen. Yeah, yeah. That they're able to survive cuz yeah, the places that like don't have a whole lot of oxygen in the water. They just, they come up to the surface to breathe. I mean, that's kind of the benefit of what they can
do.
Laura:Right. Why don't all fish do that? Right. Has developed so long ago. I can't believe it didn't catch on.
Katy:Yeah. Yeah. No one else. They were like the dorks, like no one. They're like, oh guys, I can do this. Everyone else is making fun of straight oxygen, yellow. Yeah. Yeah. This is great guys. And everyone's like making fun of me while they're the ones still. Despite their long evolutionary history, lung fish, just like crocodiles, have retained many of the same characteristics or ancient ancestors, which has led some scientists to consider them living fossils. The first fossil of a lung fish was discovered in Scotland in 1838. By a Scottish geologist, Hugh Miller, and since then, numerous fossils of lung fish and their prehistoric relatives have been found all over the world. So what makes them a living fossil is their ability, of course, just like all the others to retain. Pretty much all of the same characteristics as their ancient ancestors. Despite the millions of years of evolution, for example, they've retained their ability to breathe air. So that's something they've always been able to do to survive in low oxygen environments and even to burrow and to mode, to just. To survive droughts. So even during drought seasons, they'll dig their way and make a borough and just hunker down in there. Survivors and just, yeah, and just wait. And I'm like, okay, drought's done. Let's come back up. So all of this has made them an important subject of study for scientists, especially in evolutionary and history of life. Cuz of course they have the appendages, they can breathe there, they're fish. Is this like that, the chain, the missing link species or what? Yeah. So recent research has shed new light on the evolutionary history of lung fish and their place in the tree of life. A study published in the Journal of Nature in 2013 found that lung fish are more closely related to terrestrial vertebrates, such as reptiles and mammals than to other fish. This discovery has significant. That's crazy. Yep. So that has implications for our understanding of the evolution. Yeah. And then to fish. Yeah. So like they're like,
Laura:yeah, that's nuts. Yeah. They're more like a reptile than they are a fish, even though they look just like a fish. A
Katy:fish. Yep. That's nuts. So in conclusion, the lung fish, they are a fascinating group of ancient fish species that have survived for over 400 million years. They're known for their unique ability to breathe air, their low reproductive rate, and their amazing ability to survive in harsh environments. And that's how they were able to stay around for so long. That's crazy.
Laura:What a cool animal. I think. I kind of think they're cute. I think they look a little bit like an axolotl just without the guilt, like the frills. Yeah. I just think they're really like, their faces kind of look like. And I like the fact that they can kind of walk. I kind of, I kind of want
Katy:one, but it's gotta be like a hobble, you know? Like a,
Laura:like a Yeah, yeah. Or, but they must like look like they're gliding when they're underwater.
Katy:If you say so. Well, make sure you guys go talk with us and follow us on Twitter and then check out our Patreon page for the Love of Nature. You can find us there to support us so we can keep bringing you random content like this.
Laura:Yeah. And you know, we will be back on track to be releasing episodes every. Lord willing, and the sun do shine isn't, is that the phrase and the
Katy:sh and the sun do shine.
Laura:I, I can't remember if that's the real phrase but now that you know, probably more than you wanted to know, your curiosity should be peaked and hopefully you care just a little bit more. Talk to you
Katy:next week. Bye.