Speaker 1: My Welcome to Stuff to Blow Your Mind production of
Speaker 1: My Heart Radio. Hey you welcome to Stuff to Blow
Speaker 1: your Mind. My name is Robert Lamb and I'm Joe McCormick,
Speaker 1: and today we're beginning a series of episodes on the
Speaker 1: reptiles of the Galapacos Islands. And rob this is not
Speaker 1: a topic we just landed on randomly. This is related
Speaker 1: to your recent travels, right. Yeah. I had the great
Speaker 1: pleasure and the good fortune to visit some of the
Speaker 1: islands of the glap Coos Archipella go back in October.
Speaker 1: It was a fantastic family trip that we've been planning
Speaker 1: for a long time and we meant to do before
Speaker 1: the pandemic and then obviously we had to reschedule. But yeah,
Speaker 1: this is this is one of the top trips I've
Speaker 1: ever had the privilege to make. And now, certainly I
Speaker 1: was visiting as a tourist, but but one of the
Speaker 1: things about the Glapos Islands that I love is so
Speaker 1: much of the tour is um there is about the
Speaker 1: natural beauty of the place. It's about the environments, it's
Speaker 1: about the animals and um. And so if you're you're
Speaker 1: going all the way to the Galapagos Islands. You you
Speaker 1: probably want to see some reptiles, you probably want to
Speaker 1: see some birds, etcetera. And they really facilitate that. The
Speaker 1: local guides are are all terrific, all the ones that
Speaker 1: that I interacted with, a very knowledgeable of everything going
Speaker 1: on there. And yeah, it was a trip just unlike
Speaker 1: any other, especially when when observing these various creatures, because
Speaker 1: it was kind of like being a Disney princess, like
Speaker 1: being in a Disney like a Disney princess scene in
Speaker 1: a movie, except instead of the princess being surrounded by
Speaker 1: cute squirrels, bunnies and birds that are singing, you're just
Speaker 1: constantly surrounded by this wonderfully bizarre cast of reptiles and
Speaker 1: elaborate birds, sea lions. It's and it's unlike too. I
Speaker 1: have to say, it's unlike the vibe that I've encountered
Speaker 1: in places like the Grand Canyon, where they'll be wild
Speaker 1: animals there that are protected and so accustomed to humans
Speaker 1: that the humans can get like unnaturally and alarmingly close
Speaker 1: to those animals. There's a proximity to the animals on
Speaker 1: the Galapicos Islands that um that that that feels less
Speaker 1: artificial but also equally magical, if that makes sense. Again,
Speaker 1: not to say that you should attempt to touch any
Speaker 1: of the animals there or or or or infringe upon
Speaker 1: their personal space in any way, but there's this, Yeah,
Speaker 1: there's this feeling of proximity to nature that makes you
Speaker 1: feel like you are David Attenborough in a David Attenborough documentary. Um,
Speaker 1: you know, creeping up for a close look at this
Speaker 1: animal or another, and maybe you are the camera lens.
Speaker 1: And I wonder if the difference with the Grand Canyon
Speaker 1: thing would be the difference between animals that are unfortunately
Speaker 1: habituated to human presence in all the wrong ways, like
Speaker 1: expecting you to have food, the calorie rich food sources
Speaker 1: and stuff, so they'll come up to you looking for that,
Speaker 1: versus a place where animals don't seem to flee from
Speaker 1: humans because there they come from many generations of animals
Speaker 1: without natural land predators. Yeah. Yeah, and uh, I believe
Speaker 1: that is the case with the Clap of Coasts. So
Speaker 1: let's let's introduce everybody to the to the clap Coost Islands.
Speaker 1: If you're not familiar with the clap of Coost Archipelago,
Speaker 1: it is a chain of islands in the eastern Pacific Ocean,
Speaker 1: roughly nine sixty six kilometers or six hundred miles off
Speaker 1: the coast of Ecuador. It consists of thirteen major islands
Speaker 1: a few smaller islands, and these were all formed by
Speaker 1: repeated volcanic eruptions. The process here is similar to that
Speaker 1: which produced the Hawaiian islands, which we've discussed in the
Speaker 1: show before. So they're not formed all at once, but
Speaker 1: in a chain due to underlying volcanic activity berthing mountains
Speaker 1: and islands out of the ocean floor. So, as with
Speaker 1: the Hawaiian islands, the islands here and the Galapaos are
Speaker 1: geologically quite young, and their individual ages vary. Now, Joe,
Speaker 1: I'm not sure what age ranges you've come across for
Speaker 1: them when we get into the geologic age of the
Speaker 1: galapaost islands, but I've seen it very a bit. The
Speaker 1: Galapa Ghost Conservatory says quote probably no more than five
Speaker 1: million years with the younger volcanically active westernmost islands perhaps
Speaker 1: as young as hundreds of thousands of years old, but
Speaker 1: the idea that none of the islands there today are
Speaker 1: are more than five million years old. According to some
Speaker 1: of the dates that I was looking at me at
Speaker 1: least sighted dates, but just sort of casting a wide net.
Speaker 1: I did see some other dates out there, so um,
Speaker 1: you know, I can only speak to the ones I'm
Speaker 1: sighting here. Well, estimates very a bit, but it also
Speaker 1: depends on what you're counting as the Galapa Coost Islands.
Speaker 1: For example, I was reading a passage in a book
Speaker 1: Galapagos a Natural History, second Edition by John Creature and
Speaker 1: Kevin Laughlin from Princeton University Press. That new edition is
Speaker 1: just just out this year in two and there is
Speaker 1: a section in this book where the authors put forward
Speaker 1: the possibility that some species on the islands, including the
Speaker 1: famous giant tortoises, may have inhabited the Galapagos since before
Speaker 1: any of the Galapagos Islands existed. Now, how could that
Speaker 1: be possible, Well, here's what they argue. If you look
Speaker 1: around the area of the archipelago, especially east of the
Speaker 1: existing islands, you will see what are called sea mounts,
Speaker 1: which are submerged islands. They are areas where the ocean
Speaker 1: floor rises up to form a mountain, but that mountain
Speaker 1: does not break through the surface of the water, so
Speaker 1: it's not an island. From our perspective, but it's sort
Speaker 1: of like an island just beneath the water. Now, what
Speaker 1: are these sea mounts in the eastern part of the archipelago. Well,
Speaker 1: Creature and Laughlin right that they are quote eroded volcanic islands,
Speaker 1: and that they are possibly the original ancestral Galapagos. So
Speaker 1: they were once perhaps islands that did break above the surface,
Speaker 1: but have eroded over time. Uh and the the authors
Speaker 1: here site a group of oceanographers and geologists led by
Speaker 1: a researcher named D. M. Christie, who put together some
Speaker 1: dates for these seamounts and said that the dates ranged
Speaker 1: from between five to nine million years, which is older
Speaker 1: than any of the existing Galapagos islands today. So to
Speaker 1: read from this passage quote, as Christie's team pointed out,
Speaker 1: if the original Galapagos islands formed as much as nine
Speaker 1: million years ago, there has been more time for colonization
Speaker 1: and subsequent evolution than once believed. This is colonization by
Speaker 1: non human animals. There may well have been tortoises on
Speaker 1: the islands for longer than any of the present day
Speaker 1: islands have been in existence, given regular albeit accidental dispersal,
Speaker 1: new islands forming over the hot spot will be colonized
Speaker 1: even as old islands a road and disappear beneath the
Speaker 1: sea from whence they came. So normally you're talking about
Speaker 1: island an island group, you would imagine that, Okay, well,
Speaker 1: the earliest it could have been colonized by animal species
Speaker 1: is whenever the islands we have today began. But in
Speaker 1: the case of the Galapagos, uh, A lot of the
Speaker 1: evidence of the earliest colonization by animals could be under
Speaker 1: the waves. It could just be lost because those islands
Speaker 1: aren't there anymore. M Yeah, there's sort of the lost
Speaker 1: animal kingdoms of the globos potentially. Now when we're we're
Speaker 1: talking about the the modern day Galapkos islands, uh, some
Speaker 1: of the main ones, just to mention them real quick.
Speaker 1: You have Isabella, which is the largest. You have Santiago, Uh, Fernandina,
Speaker 1: you have Santa Cruz, you have San Cristobil. I only
Speaker 1: really visited Santa Cruz and San Cristobul and a couple
Speaker 1: of smaller, unoccupied um by humans islands that were quite fascinating.
Speaker 1: And one of the things about these islands, and you've
Speaker 1: often encountered this with with volcanic highland formations is that
Speaker 1: they're defined by steep out elevation changes and the resulting
Speaker 1: islands that contain multiple microclimates due to this, So a
Speaker 1: visit to even a single Glabacos island is an encounter
Speaker 1: with multiple and varied ecosystems. Right, So you'll get different
Speaker 1: climates and different vegetation and so forth at different elevations
Speaker 1: on the island. So uh and and that type of
Speaker 1: like what vegetation is flourishing therefore might vary with the seasons.
Speaker 1: So when the rainy season comes, you might get more
Speaker 1: blossoming of vegetation in the lower areas, but then other
Speaker 1: times animals might find the most fruitful foraging up in
Speaker 1: the highlands. Yeah. Yeah, So it's any one of these islands,
Speaker 1: you'll have, you know, have sort of desert environments, you'll
Speaker 1: have highland lush environments, you'll have coastal and Ironman's and
Speaker 1: these are these are This is one of the reasons
Speaker 1: that these islands are often singled out historically, but even
Speaker 1: in modern research is kind of a laboratory of evolution. Now,
Speaker 1: I'm going to keep referring back to Hawaii a little
Speaker 1: bit for for a while, because I think it's a
Speaker 1: nice sort of touchtone to compare, especially since we've we've
Speaker 1: talked about those islands on the show before as well.
Speaker 1: Um So when it comes to Hawaii, as we've discussed before,
Speaker 1: you have such geographic isolation that with those islands, so
Speaker 1: there are actually no native land reptiles or amphibians there.
Speaker 1: So anything in the categorization of reptiler amphibian that you
Speaker 1: find there were introduced by subsequent human arrivals by boat
Speaker 1: or ultimately air. That's the Hawaiian Islands. We don't have
Speaker 1: the same situation with the Glabcost Islands for a few
Speaker 1: different reasons. So as far as humans go, first human
Speaker 1: contact with Glavicos comes a bit later. We're talking about
Speaker 1: fifty five versus Hawaii's betwe Queen. And also Hawaii is
Speaker 1: a greater distance from the nearest continental land mass and
Speaker 1: I shouldn't know that, I think I pointed this on
Speaker 1: the show before, But there is some dispute on whether
Speaker 1: the Inca ever reached the island, but we can be
Speaker 1: certain that Europeans reached the island in yeah, exactly three
Speaker 1: hundred years before Darwin did. By the way, yeah, thank
Speaker 1: thank so. The story of the first confirmed human landing
Speaker 1: on the Galapagos is very interesting, so I wanted to
Speaker 1: tell it here. There was this Spanish clergyman named Thomas
Speaker 1: de Borlonga who was a bishop. He eventually served as
Speaker 1: the bishop of the Colony of Panama, and I've read
Speaker 1: it alleged in several sources that Burlongo was responsible for
Speaker 1: introducing bananas or plantains to the New World, which is
Speaker 1: weird because despite how much we associate bananas with the
Speaker 1: Caribbean and South America, they are originally native to Southeast Asia.
Speaker 1: So it is alleged that this guy is responsible for
Speaker 1: bringing bananas over, but I'm not sure what the original
Speaker 1: source of this claim is. Anyway. In five Blonga was
Speaker 1: traveling by ship from Panama to Peru to help sort
Speaker 1: out some kind of horrible sounding squabble between the conquistador
Speaker 1: Francisco Pizzarro and another conquistador over land and spoils after
Speaker 1: their conquest of the the Inca Empire. So Berlonga is
Speaker 1: on the way down to try to help sort this out,
Speaker 1: but as his ship is traveling south along the coast
Speaker 1: during the first half of the journey, it is suddenly
Speaker 1: struck by a dead calm that prevents the ship from
Speaker 1: sailing further, and then it gets dragged far off course
Speaker 1: out to see by strong ocean currents, and just when supplies,
Speaker 1: including fresh water, are about to run out, the crew
Speaker 1: sites land. Their prayers have been answered, but like so
Speaker 1: many early visitors, the Spaniards are almost instantly dejected by
Speaker 1: what they find. The first island where they land is
Speaker 1: found to have not a single drop of fresh water,
Speaker 1: and there's also no pasture where their horses can graze,
Speaker 1: just a bunch of giant tortoises and weird iguanas. But
Speaker 1: there were other islands nearby, so the crew tried to
Speaker 1: sail to another one to continue the search for water. Unfortunately,
Speaker 1: on the way they were once again be calmed and
Speaker 1: could not sail for several days, while just languishing there
Speaker 1: on the ship, nearly dying of thirst. Finally the wind
Speaker 1: picked up again and they were able to reach a
Speaker 1: second island, where once again they found no fresh water.
Speaker 1: They tried to dig a well, but when they struck groundwater,
Speaker 1: they found it to be as bitter as the sea.
Speaker 1: And here I want to read from the retelling of
Speaker 1: this story by the famous naturalist William bbe in his
Speaker 1: book galapagost World's End, A published nine BB rights. In
Speaker 1: their extremity, they had recourse to a plant which has
Speaker 1: saved many a thirsty man and animal, And by chewing
Speaker 1: the fruit and juicy stalks of the cactus, they kept
Speaker 1: themselves alive. They took a page from the tortoise playbook there. Yeah, uh,
Speaker 1: not all withstood these privations. One man and two horses
Speaker 1: died of thirst. And so the first grave on the
Speaker 1: Galapagos was dug. Sunday came and the bishop celebrated high
Speaker 1: Mass on those desolate shores, where as he said, quote,
Speaker 1: it looked as though God had caused it to rain stones,
Speaker 1: brutal doom metal bishop uh. And then Babe goes on sea.
Speaker 1: Lions slipped through the creaming surf and looked curiously at
Speaker 1: the little group of strange beings and long winged seabirds
Speaker 1: poised and swooped above the cross and the Spanish flag
Speaker 1: planted side by side among the cactus and thorny scrub.
Speaker 1: So I think Babe has taken a little liberty with
Speaker 1: the storytelling there, but all plausible, you know, given the
Speaker 1: given the local of flora and fauna. Yeah, desolate beaches,
Speaker 1: weird sea lions hanging about, Well, I guess they sea
Speaker 1: lions generally described her as weird. They would have certainly
Speaker 1: been exposed to sea lions already, But in my book,
Speaker 1: sea lions are inherently strange but also very amusing to watch.
Speaker 1: They're just playfully rolling about while these people have church
Speaker 1: dying of thirst. So finally, after the worship service, the
Speaker 1: Spaniards did find some small amount of fresh water. I've
Speaker 1: seen what they found alternately described as a spring water
Speaker 1: and as little pools collected in cup shaped depressions in
Speaker 1: the rocks. And using this water, either the spring water
Speaker 1: or the rock pools, they filled up their containers and
Speaker 1: they departed again for the coast of Peru. Now. Burlonga
Speaker 1: made a number of observations while on the island, writing,
Speaker 1: according to an eight eight four translation of his letters,
Speaker 1: that the animals of the Galapagos were quote so silly
Speaker 1: that they not know how to flee uh, and that
Speaker 1: as a result, wild animals were easily caught in the hand. Well,
Speaker 1: that does match up, I think with the reality of
Speaker 1: visiting the Glabicos Islands even today. Not that you should
Speaker 1: be chasing any of the animals and certainly not catching
Speaker 1: them in the hand. But yeah, there is this, like
Speaker 1: I said, there's this sense that, um like, they don't
Speaker 1: necessarily understand what we are and they're not threatened by
Speaker 1: us unless we get too close, and then a lot
Speaker 1: of these animals will let you know. So, yeah, don't
Speaker 1: don't get too close to the sea lions wherever you
Speaker 1: find your sea lions. Don't get too close to the
Speaker 1: tortoises of the iguanas. Now, Rob, you mentioned that the
Speaker 1: tourism at the Galapagos today is almost entirely centered around
Speaker 1: the islands natural beauty and biological and ecological significance. You know,
Speaker 1: this is a place where you go to see the
Speaker 1: natural landscape and the flora and fauna. You're not going
Speaker 1: there to see to go to six Flags Galapagos, right right, Um, Yeah,
Speaker 1: and yeah, I mainly mean, yeah, you're not gonna find that.
Speaker 1: You're not gonna find. I didn't really see much in
Speaker 1: the way of like a party boat kind of culture
Speaker 1: that you find in a lot of locations. It's, um,
Speaker 1: you know that there is there is culture there. There's
Speaker 1: some some great restaurants, there's there's great local culture and
Speaker 1: the people who live there. Uh. We were on the
Speaker 1: whole very friendly and uh and I loved interacting with
Speaker 1: them quite a bit. But yeah, it's when people go
Speaker 1: to the Galapacos. I mean, the main selling point, the
Speaker 1: big deal for for everyone seems to be the natural
Speaker 1: world that is available to you there. And despite this
Speaker 1: modern appreciation for the natural beauty and wondrous ecological significance
Speaker 1: of the Galapagos, a recurring theme among early visitors is
Speaker 1: a reaction exactly the opposite. So in the novel Galapagos,
Speaker 1: Kurt Vonnegut wrote that the early Spanish explorers quote did
Speaker 1: not claim the islands for Spain anymore than they would
Speaker 1: have claimed Hell for Spain. M I haven't read this novel,
Speaker 1: but I did see it in bookstore. There was a
Speaker 1: nice bookstore on one of the islands and the Collapacos,
Speaker 1: and they had it there. They were probably had several
Speaker 1: Darwin related books, and then they had Vanagats Glapacos, and
Speaker 1: I was tempted to pick it up, but then I
Speaker 1: was like, I don't know if I'm in the mid
Speaker 1: for post apocalyptic literature at the moment. I've actually never
Speaker 1: read that one either, but so yeah, it just seemed
Speaker 1: like the Spanish were not very interested for a while.
Speaker 1: There were apparently no notable mineral riches to mine, at
Speaker 1: least that they were aware of, uh, no people living
Speaker 1: there to conquer or enslave. There was very little fresh water,
Speaker 1: so the Spanish just did not seem very interested in
Speaker 1: these islands. And during the seventeenth century it seems like
Speaker 1: the Galapagos largely served as a base for people who
Speaker 1: didn't want to be found, for pirates and privateers. Privateers
Speaker 1: would attack Spanish ships to steal the gold that the
Speaker 1: Spanish had stolen from the Incas, or just pirates who
Speaker 1: attacked and rated coastal settlements on the mainland. Yeah. Yeah,
Speaker 1: when when it comes to the human history of the
Speaker 1: clab because it's easy to sort of think, oh, well, Darwin,
Speaker 1: uh and then you sort of fast forward to today.
Speaker 1: But yeah, there's a lot of bloody history there. It
Speaker 1: was this It was an extreme location that, like you said,
Speaker 1: I didn't have a lot seemingly to offer except as
Speaker 1: a place of refuge for people engaged in various bloody activities.
Speaker 1: Sometimes it seemed like a place for utopia, utopian ideals,
Speaker 1: and um, of course those sorts of ventures don't always
Speaker 1: turn out well either. So yeah, there's there's a very
Speaker 1: interesting human history there that is not all just bird
Speaker 1: watching by any means. Uh. Though, continuing the theme of
Speaker 1: like the the lack of appeal of the islands too
Speaker 1: many people who first arrived there, Charles Darwin himself wrote
Speaker 1: of his first impression of San Cristobal Island that quote,
Speaker 1: nothing could be less inviting. That's that's that's funny because
Speaker 1: they're on Sant Christoble Island. You know, there's like a
Speaker 1: statue of of of Charles Darwin in the ship with
Speaker 1: his hand out and I had I got my picture
Speaker 1: made with this, of course, but there, yeah, there statutes
Speaker 1: of Darwin all over the islands. Nice. Um now, well, yeah,
Speaker 1: I mean, you know, Darwin warmed up, you know, he
Speaker 1: there's a lot to learn there. But but yeah, apparently
Speaker 1: first setting eyes on it, he was like not cool. Yeah,
Speaker 1: that's not the quote that's like on a plaque. Besides this,
Speaker 1: h Now, regarding uh, this story about Burlonga's accidental landfall
Speaker 1: in the Galapagos being the first confirmed human visit, it
Speaker 1: is important to stress that this is the first visit
Speaker 1: by humans were sure about but They're all kinds of
Speaker 1: interesting arguments about whether or not others had been there before,
Speaker 1: and their theories of contact regarding the Inca's Pacific peoples
Speaker 1: and so forth. But I think all of these are
Speaker 1: speculative and the the evidence is questionable there. There was
Speaker 1: certainly no permanent human settlement in pre Columbian times, and
Speaker 1: the earliest arrivals by humans appeared to be by accident. Yeah,
Speaker 1: you get into that situation though, where if earlier people's
Speaker 1: had come there, they probably wouldn't have stuck around, and
Speaker 1: what would they have left behind, what evidence would there be?
Speaker 1: So yeah, we're left to speculation. Now, coming back around
Speaker 1: to uh, the reptiles, which is going to be the
Speaker 1: main thing we're talking about in these episodes. Um. Again,
Speaker 1: the Hawaiian Islands no native reptiles, but we have these
Speaker 1: fascinating examples of reptiles on the Galapacos Um. So while
Speaker 1: while while reptiles never had the chance to to reach
Speaker 1: the Hawaiian Islands on their own, the Glaphicos Islands are
Speaker 1: in just the right position. It seems to have been
Speaker 1: gifted some wandering um lost at sea reptiles. Uh. And
Speaker 1: yet at the same time, isolated enough that they were
Speaker 1: able to evolve their unmolested for a very long time. Um.
Speaker 1: So it's kind of fascinating to think about that. Like,
Speaker 1: if they had been in any other location, you know,
Speaker 1: there might have been a situation where, yes, humans would
Speaker 1: have found this place and colonized it much earlier. It
Speaker 1: might be in a position where these reptiles would not
Speaker 1: have reached it of their own power or by the
Speaker 1: power of wind and water, which seems to be the case.
Speaker 1: I think in the main examples of terrestrial reptiles reaching
Speaker 1: the Galapagos Islands, they tend to involve rafting. They tend
Speaker 1: to involve animals being um, just swept out to see
Speaker 1: via rivers in South America. And then you know, a
Speaker 1: number of those animals are going to perish, but some
Speaker 1: of them are going to find themselves cast upon a
Speaker 1: deserted island, and from there they begin to find ways
Speaker 1: to survive and these new forms evolve. Well, this sounds
Speaker 1: like a perfect transition to the marine iguana. Robbert, you ready, Yeah,
Speaker 1: let's talk about the marine iguana. Probably not the most
Speaker 1: famous denizen of the islands, but at least number two. Yeah, yeah,
Speaker 1: and certainly maybe the most uh salient in my brain
Speaker 1: because specifically, to come back to Darwin, Charles Darwin's discussion
Speaker 1: of the marine iguana or scientific name ambly Rinkus Chris
Speaker 1: Tatis and the Voyage of the Beagle has long stuck
Speaker 1: in my head. So of course, the Voyage of the
Speaker 1: Beagle is the common name used to refer to the
Speaker 1: published writings of Charles Darwin after his sales on on
Speaker 1: the HMS Beagle with Captain fitz Roy and this, uh,
Speaker 1: this chapter on the Galapagos in the Voyage of the
Speaker 1: Beagle is very famous, but the subsection on the marine
Speaker 1: iguana has long stuck in my head, notably for the
Speaker 1: weird disrespect with which Darwin treats these animals. Uh. So
Speaker 1: I want to read a few selections as we go
Speaker 1: about here from this passage in the Beagle with some
Speaker 1: abridge mints. But to start off, this is what Darwin
Speaker 1: says talking about the marine iguana. It is extremely common
Speaker 1: on all the islands throughout the group and lives exclusively
Speaker 1: on the rocky sea beaches, being never found at least
Speaker 1: I never saw one even ten yards inshore. It is
Speaker 1: a hideous looking creature of a dirty black color, stupid
Speaker 1: and sluggish in its movements. Uh. And in his journal
Speaker 1: he refers to them initially as quote, large, disgusting, clumsy lizards. Well,
Speaker 1: I mean they do lay around in clumps um, which
Speaker 1: I could imagine some seeing this as being kind of
Speaker 1: gross looking. But in the same in this, on the
Speaker 1: same note, the way they kind of lounge around. Sometimes
Speaker 1: they seem oddly human in the way like one al
Speaker 1: sometimes have an arm slung over the shoulder of another.
Speaker 1: Like it's like it's too like it's an old married
Speaker 1: couple staring out at the sunset or something. Puppy pile. Yeah, yeah,
Speaker 1: kind of a puppy pile. And and there is kind
Speaker 1: of an awkwardness to them sometimes when they move around
Speaker 1: on land. But I don't know, that's kind of charming
Speaker 1: more than anything. So early chroniclers often used the same
Speaker 1: kind of terms. They call this animal ugly, hideous. Some
Speaker 1: of them make bizarre value statements, such as comparing them
Speaker 1: to devils or imps of darkness. Uh. Darwin himself, in
Speaker 1: The Beagle quotes a description by a previous author, a
Speaker 1: Captain Colnett, who visited the Galapagos, who says, in the
Speaker 1: part of his work that Darwin quotes, quote they go
Speaker 1: to sea in herds of fishing and sun themselves on
Speaker 1: the rocks, and maybe called alligators in miniature and elsewhere.
Speaker 1: Colne marveled at their ugliness, writing quote, so disgusting is
Speaker 1: their appearance that no one on board could be prevailed
Speaker 1: upon to take them as food. Not even sailors would
Speaker 1: eat them. And I'm gonna say I take personal offense
Speaker 1: to all this. I think marine iguanas are beautiful. I
Speaker 1: want to hug and kiss them. I know I shouldn't.
Speaker 1: I would never do that, but I want to. Yeah,
Speaker 1: they do look kind of like jumps, but I think
Speaker 1: in a good way. I often we often thought that
Speaker 1: they looked kind of like tiny Godzilla's. Something about the
Speaker 1: the shape of their their heads and their snouts and
Speaker 1: of course the little, uh you know, protrusions on the
Speaker 1: top of their head give them kind of a a
Speaker 1: kaiju appearance, and um that and there's so many things
Speaker 1: about them that there's just a lot of times that
Speaker 1: you know, they're lounging around, they're not doing anything, but
Speaker 1: then when they are moving about, even on the land,
Speaker 1: they can be quite amusing. Like, for instance, if one
Speaker 1: is making a bee line for something, especially if one
Speaker 1: is coming out of the water or it's time to
Speaker 1: go to the water. Sometimes something will seem to get
Speaker 1: in the way of their their journey, like maybe a
Speaker 1: sea lion or a human wanders into their path, and
Speaker 1: they'll just kind of stop and they'll they won't skitter
Speaker 1: out of the way or anything, but there's kind of
Speaker 1: wait until whatever did is it has moved on, and
Speaker 1: then they'll keep going. So there's is kind of like
Speaker 1: laid back care free of energy to these creatures. They're
Speaker 1: kind of wasted away again in Margaritaville. Yeah. Yeah, by
Speaker 1: the way, you mentioned their stubby little snouts. That's actually
Speaker 1: what the genus name means, ambly Rincus means blunt snout. Ah. Well,
Speaker 1: we'll come back to that blunt snout of that. Thank However,
Speaker 1: to come back to Darwin's writings on the marine iguana.
Speaker 1: His unseemly anti iguana prejudice aside, he does make some
Speaker 1: correct observations about them. For example, Captain Colnett remember said
Speaker 1: that they go a fishing and sea herds. You know
Speaker 1: they're going to go out and catch fish. Darwin says,
Speaker 1: I don't know about that. He challenges the idea that
Speaker 1: they eat fish, and in fact we now know they
Speaker 1: do not. Instead, Darwin observes that these animals seem to
Speaker 1: subsist on a kind of seaweed or algae which cannot
Speaker 1: be found on land, and he reasons that this explains
Speaker 1: why they evolved to go to sea in the first place. Yeah,
Speaker 1: I mean this is this is spot on, of course,
Speaker 1: and then we'll get into into it more in a bit.
Speaker 1: But but yeah, and it's also very observable if you're
Speaker 1: watching the creatures, because sometimes they're going to be uh,
Speaker 1: eating algae that's under the water and perhaps out of you.
Speaker 1: But other times it's it's algae, especially as the tides change,
Speaker 1: it's like partially and partially out of the water, so
Speaker 1: you can see them they're munching, grazing on the alergae
Speaker 1: on the rock. So as a side note, Darwin says
Speaker 1: one dissected iguana stomach did have a piece of crab
Speaker 1: in it, though he thinks this might have been eaten
Speaker 1: by accident, and he compares this two cases where a
Speaker 1: vegetarian tortoise has a caterpillar in its stomach, because the
Speaker 1: caterpillar was just on the leafy vegetation the tortoise was eating.
Speaker 1: In fact, we've done whole segments about this on the
Speaker 1: show before, about herbivores eating animals accidentally or even sometimes
Speaker 1: on purpose. Yeah. But after introducing them, Darwin goes on
Speaker 1: to describe the animals in detail, describing their movement. It's
Speaker 1: with a strange mix of admiration and disgust. So here's
Speaker 1: what he says. Quote. When in the water, this lizard
Speaker 1: swims with perfect ease and quickness by a serpentine movement
Speaker 1: of its body and flattened tail, the legs being motionless
Speaker 1: and closely collapsed on its sides. A seman on board
Speaker 1: sank one with a heavy weight attached to it, thinking
Speaker 1: thus to kill it directly, but when an hour afterwards
Speaker 1: he drew up the line, it was quite active. Their
Speaker 1: limbs and strong claws are admirably adapted for crawling over
Speaker 1: the rugged and fissured masses of lava which everywhere formed
Speaker 1: the coast. In such situations, a group of six or
Speaker 1: seven of these hideous reptiles may oftentimes be seen on
Speaker 1: the black rocks a few feet above the surf, basking
Speaker 1: in the sun with outstretched legs, and then He goes
Speaker 1: on to note a strange, perplexing, almost contradictory observation about
Speaker 1: their behavior. So, while the iguanas go to sea in
Speaker 1: order to forage, that's how they make a living there.
Speaker 1: They swim out in the water, get the algae, and
Speaker 1: eat it. He found that he could not scare them
Speaker 1: into the water. If he approached one, it would back
Speaker 1: away from him until it reached the edge of a
Speaker 1: rock hanging over the water. But once at that point
Speaker 1: it would stop retreating. It would just let him approach
Speaker 1: and catch it, rather than flee into the water. And
Speaker 1: here we come to the infamous iguana chucking scene of
Speaker 1: the Voyage of the Beagle. Darwin writes, I threw one
Speaker 1: several times as far as I could into a deep
Speaker 1: pool left by the retiring tide, but it invariably returned
Speaker 1: in a direct line to the spot where I stood.
Speaker 1: It swam near the bottom with a very graceful and
Speaker 1: rapid movement, and occasionally aided itself over the uneven ground
Speaker 1: with its feet. As soon as it arrived near the edge,
Speaker 1: but still being underwater, it tried to conceal itself in
Speaker 1: the tufts of seaweed, or it entered some crevice. As
Speaker 1: soon as it thought the danger was past, it all
Speaker 1: out on the dry rocks and shuffled away as quickly
Speaker 1: as it could. I several times called this same lizard
Speaker 1: by driving it down to a point, and though possessed
Speaker 1: of such perfect powers of diving and swimming, nothing would
Speaker 1: induce it to enter the water. And as often as
Speaker 1: I threw it in, it returned in the manner above described. Uh. Now,
Speaker 1: this is indeed a really odd bit of behavior, right, yeah,
Speaker 1: so it would seem. Um. Now, before we get into that,
Speaker 1: I want to just mentioned I want to want to
Speaker 1: make two comments about Darwin's writing here. First of all,
Speaker 1: I do get the impression that perhaps Darwin was not
Speaker 1: a cat person or had had a cat, because like,
Speaker 1: this is the same, the same situation I think any
Speaker 1: cat owner can attest to. It's like I tried to
Speaker 1: put the cat where I wanted it to be, and
Speaker 1: it did not want to be there, So strange. Um.
Speaker 1: But but on the other hand, I do love the
Speaker 1: part where he talks about how graceful they are in
Speaker 1: the water, because that is also a huge tree getting
Speaker 1: to watch these uh, these these lizards. It's a swim
Speaker 1: about because it's I mean, it's it's unlike anything you
Speaker 1: see with any other species on the planet. There's this
Speaker 1: this graceful, indeed serpentine movement to them. There whatever awkwardness
Speaker 1: you might observe on the land is not present in
Speaker 1: the water. And it's yeah, it's like watching a strange
Speaker 1: aquatic little dragon move about. Well, I think it's also
Speaker 1: about the way that like they anatomically modify themselves to
Speaker 1: move in the water versus on land, because as Darwin says,
Speaker 1: they collapse their legs to the side and almost become
Speaker 1: a snake in the water. Yeah, but with their their
Speaker 1: heads up in a in a way that like you
Speaker 1: wouldn't mistake it for a snake. Like the profile of
Speaker 1: the swimming marine iguana is unlike anything certainly that I've
Speaker 1: ever seen. So it really stands out in your mind,
Speaker 1: like your mind instantly is identifying that this is something different,
Speaker 1: This is something novel. I agree, and having seen not
Speaker 1: in person, but seen plenty of you know, video of it.
Speaker 1: They are beautiful when they're swimming. But to come back
Speaker 1: to this odd behavior or so Darwin says, Okay, these
Speaker 1: things they go in the water all the time. That's
Speaker 1: how they eat, They go down in the water, they eat,
Speaker 1: they come back. How come I can't scare one into
Speaker 1: the water or get it to stay in the water
Speaker 1: by throwing it in. I throw it in the water
Speaker 1: just comes back out. Darwin comes up with a guess
Speaker 1: about why it acts this way. He says, quote, perhaps
Speaker 1: this singular piece of apparent stupidity may be accounted for
Speaker 1: by the circumstance that this reptile has no enemy whatever
Speaker 1: on shore, whereas it's at sea it must often fall
Speaker 1: prey to the numerous sharks, hence probably urged by a
Speaker 1: fixed and hereditary instinct that the shore is its place
Speaker 1: of safety. Whatever the emergency may be, it there takes refuge. So, okay,
Speaker 1: that's an interesting guess. He says. It has natural predators
Speaker 1: in the water, but not on land, so it just
Speaker 1: feels safer on land, even if here I am threatening
Speaker 1: it on land, because it's just acting out of instinct. Yeah, yeah,
Speaker 1: it would seem to be a decent theory. And in
Speaker 1: eat on land that nothing really messes with them except
Speaker 1: when they're smaller, and when they're smaller, they're you know,
Speaker 1: like this is the case with a number of iguanas
Speaker 1: and lizards like, until they reach a certain size, they're
Speaker 1: on the menu for various other creatures and birds and whatnot.
Speaker 1: But once they reach a certain uh maturity, Uh yeah,
Speaker 1: they can just bask where they want. Nothing's gonna mess
Speaker 1: with them. Yeah, well, at least in the ancestral environment
Speaker 1: of the glass. Now introduced dogs and pigs and all
Speaker 1: that stuff that humans brought there will prey on them, right,
Speaker 1: So I decided to follow up on this and see
Speaker 1: has there been any subsequent research about this behavior in
Speaker 1: marine iguanas that could confirm or deny Darwin's guests about
Speaker 1: the evolutionary reasoning there. And I found a paper that
Speaker 1: addresses exactly this topic. It is by Edmund As Hobson
Speaker 1: called Remarks on Aquatic Habitats of the Galapagos Marine Iguana,
Speaker 1: including submergence times, cleaning, symbiosis, and the Shark Threat. This
Speaker 1: was published in a journal called Copeia in teen sixty nine,
Speaker 1: and it seems that sharks do occasionally eat the iguanas
Speaker 1: as Darwin guest. A report of the contents of shark's
Speaker 1: stomachs in nineteen o three by Heller did find some
Speaker 1: marine iguanas in there, but Hobson thinks that the threat
Speaker 1: to iguanas by sharks is mostly exaggerated, given that he
Speaker 1: and his colleagues directly observed iguanas and sharks swimming in
Speaker 1: the same waters side by side, and he says almost
Speaker 1: all the time they just ignore one another entirely. To
Speaker 1: read from Hobson quote to the contrary, the general situation
Speaker 1: finds sharks swimming slowly among smaller fishes with no overt
Speaker 1: sign that they regard these animals as prey. Certainly, sharks
Speaker 1: are efficient predators when they do attack, but situations evoking
Speaker 1: attack are relatively infrequent. At Narborough Island, I saw white
Speaker 1: tipped sharks and a gray shark pass within a few
Speaker 1: meters of surface swimming iguanas, with no indication that they
Speaker 1: regarded the iguanas as prey. George Barlow and I made
Speaker 1: a similar observation involving a large hammer head at Hood Island.
Speaker 1: So if it's not a fear of sharks, what explains
Speaker 1: this behavior, Well, I would venture I guess I'd say
Speaker 1: it it has to do with temperature, that they're their
Speaker 1: thermic reasons at play here. Great thinking, and this is
Speaker 1: exactly what Hobson concludes. Hobson argues that the best explanation
Speaker 1: for this apparently weird behavior observed by Darwin is that
Speaker 1: the water is cold. You know, they have to go
Speaker 1: in there to get food, but they don't want to
Speaker 1: spend any more time in there than they have to
Speaker 1: because it's cold and their reptiles h to read from Hobson,
Speaker 1: citing another researcher named Bartholomew quote. Bartholomew in nineteen sixty
Speaker 1: six offered a more plausible explanation. After noting that iguana
Speaker 1: is basking on the rocks ashore have a preferred body
Speaker 1: temperature of thirty five to thirty seven degrees celsius, over
Speaker 1: ten degrees celsius above that of the sea. He suggested
Speaker 1: that iguanas would you're taken from the rocks and thrown
Speaker 1: into the water immediately returned to land, simply because they
Speaker 1: are reluctant to cool off. Uh and I love this explanation.
Speaker 1: It also does seem plausible to me. But I love
Speaker 1: this because it highlights something about human thinking that even
Speaker 1: Darwin himself was not immune to. Uh And Rob, I
Speaker 1: think you'll know exactly what I'm talking about here. When
Speaker 1: humans are trying to come up with explanations for an
Speaker 1: animal behavior or a feature of an animal body or something.
Speaker 1: I think humans are way too quick to jump to
Speaker 1: two types of explanations, those involving mating and those involving predation,
Speaker 1: sex and violence. Just in our brains, sex and violence
Speaker 1: are more salient explanations than all kinds of other pressures
Speaker 1: that exist in nature and do drive animal body plans
Speaker 1: and animal behaviors. Things having to do with just base
Speaker 1: physical realities of the world, like maintaining body temperature, thermoregulation,
Speaker 1: access to oxygen, all kinds of things like that that
Speaker 1: explained tons about the natural world. It's just our brains
Speaker 1: just don't jump to those things as quickly when we're
Speaker 1: looking for a hy Yeah. I think modern reptile enthusiasts,
Speaker 1: especially any who have engaged in keeping of reptiles, they'll
Speaker 1: be pretty quick to tell you, oh, yeah, temperature is important,
Speaker 1: temperature regulation. Uh, you know, the lizards, snakes, they want
Speaker 1: their warm places and and they're certainly going to realize that.
Speaker 1: But yeah, this is an easy, easy trap to fall into.
Speaker 1: I should also say I did. I did go into
Speaker 1: the water in the Galapagos snorkeling once, and it is
Speaker 1: to me a non iguana quite cold. So I can
Speaker 1: I can in some way at least understand how they
Speaker 1: feel about it. Yeah, so Mark me is convinced. I
Speaker 1: think that iguana kept swimming back and crawling out of
Speaker 1: the water after Darwin threw it in because it was
Speaker 1: getting cold and it wanted to it wanted to warm
Speaker 1: back up on the rocks. Yeah, And I think they're
Speaker 1: pretty chill, but they're like, no, it's too cold. I
Speaker 1: would like to get out, and he's like, I'm throwing
Speaker 1: you back in. He's like, to too cold. I wish
Speaker 1: to get out. It's not time it's not time out.
Speaker 1: I will get in the water when I am warmed
Speaker 1: up enough to do so. Now getting into a little
Speaker 1: bit about the evolution of the marine reptiles, um, it's
Speaker 1: it's very fascinating, especially again thinking of them as this
Speaker 1: this this really largely singular occurrence in the modern world.
Speaker 1: So I was looking at a few different sources. One
Speaker 1: of these was Marine Reptiles by Resmussen at All from
Speaker 1: Tleven published in p. Los one. They point out here
Speaker 1: that that lizards make up of all reptiles, but very
Speaker 1: few lizard species compared to say, turtles and snakes are
Speaker 1: present in our oceans, and this is this isn't getting
Speaker 1: so much into the issue of prehistoric aquatic reptiles, which
Speaker 1: do include extinct squamates like the mosasaur. The mososaurs which
Speaker 1: were actually distant relatives of modern iguanas and monitor lizards.
Speaker 1: We're pretty fascinating of themselves. They were gigantic, They reached
Speaker 1: links of up to twelve meters or forty feet. Uh.
Speaker 1: They swam in earths oceans roughly sixty six million years ago.
Speaker 1: They hunted other marine reptiles, and it's possible they gave
Speaker 1: birth to live young in the water. Uh, though I'm
Speaker 1: not sure it's it's this is certain. There's some various
Speaker 1: studies out there about possible egg finds of the mosasaurs.
Speaker 1: But it's worth mentioning here to drive home the difference
Speaker 1: between today's marine reptiles and those of the past, especially
Speaker 1: you know, thinking about sea turtles, thinking too, about the
Speaker 1: marine iguana. These are animals that um to varying degrees,
Speaker 1: are great in the water, but they still must return
Speaker 1: to shore to complete some vital stage of their um
Speaker 1: of their life, certainly with sea turtles, with with the
Speaker 1: marine iguana. It's more living on the shore but then
Speaker 1: going into the water to graze and feed. Yeah. So,
Speaker 1: of extent lizards that are in any way aquatic, there
Speaker 1: are only a few extreme examples um and this includes
Speaker 1: the Western Pacific mangrove monitor, which is a carnivore. But
Speaker 1: as the authors here point out, the galapagost marine iguana
Speaker 1: is the most aquatic of all extants lizards. It basques, breeds,
Speaker 1: and lays eggs on land, et cetera, but it has
Speaker 1: to go into the water to feed. It is, by
Speaker 1: other definitions, the only squa mate that's actually able to
Speaker 1: exploit the research sources of the ocean in a meaningful way.
Speaker 1: So the aforementioned monitor lizard, for example, can catch fish,
Speaker 1: but it also feeds on terrestrial meats as well. I
Speaker 1: should also note that there are other iguanas on the
Speaker 1: Glabos Island islands, to be sure, including seven smaller species
Speaker 1: and three species of land iguanas in the genus um Conelphus.
Speaker 1: They include the beautiful and rare Galapagos pink iguana, which
Speaker 1: is a most special creature. Included a picture of this
Speaker 1: for you, Joe and everyone out there. You should look
Speaker 1: up a picture of the Galapa those pink iguana. This
Speaker 1: is not something I got to see when I was there,
Speaker 1: because it lives in a very remote part of the islands.
Speaker 1: Uh not not even even locals don't usually get to
Speaker 1: see this creature. The first thing that popped into my
Speaker 1: head is it looks kind of like a hot dog. Yeah, yeah,
Speaker 1: it's you know, it's it's it's it's especially it's an
Speaker 1: iguana pink. But yeah, they're these are these are rare
Speaker 1: and beautiful creatures. But again, the marine iguana is the
Speaker 1: real standout here. The other guanas are a lot of
Speaker 1: fun to watch too, if you if you visit, but
Speaker 1: the marine iguana is special. The average adult is around
Speaker 1: one point two meters in length, so they're not huge,
Speaker 1: and they're found out virtually every island of the Galapacos,
Speaker 1: Thank thank so. Coming back to the question, how did
Speaker 1: any of these lizards get to the far flung Galabicos islands,
Speaker 1: The answer, according to Resmussen at All, is probably that
Speaker 1: they're all related to iguanas from South America that were
Speaker 1: washed from the South American mainland, again perhaps by river floods,
Speaker 1: and carried out to the Galapagos, and again this is
Speaker 1: where the Galapagos is isolation yet closer proximity to a
Speaker 1: continental mainland comes into play. The theory is also in
Speaker 1: part supported by the fact that as distinct as the
Speaker 1: four bigger iguanas of the Galapagos Islands, including the Marine iguana, are,
Speaker 1: they are closely related and they actually can breed with
Speaker 1: one another to produce hybrids. So hybrids have been reported.
Speaker 1: According to rest Moodsen, at all, the marine iguanas spend
Speaker 1: quite a bit of time in the water, though foraging
Speaker 1: for their food. As adults, they feed almost exclusively on
Speaker 1: the red and green algae there it's been pointed out
Speaker 1: there not above at least trying out the odds grape
Speaker 1: scrap of this, that or the other. And perhaps that
Speaker 1: accounts for the the crab claw that Charles Darwin reported.
Speaker 1: And there's at least one population of the marine iguanas
Speaker 1: that has been observed to supplement their diet with land plants.
Speaker 1: But for the most part, their hind gut has evolved
Speaker 1: to thrive on the algae. Like they're they're bound to
Speaker 1: the algae. This is not just a this is not
Speaker 1: just a lifestyle choice. At this point, and their bodies
Speaker 1: have adapted in other key ways as well to allow
Speaker 1: this marine diet due to the considerable selection pressure that's
Speaker 1: been applied to them, which is quite literally the selection
Speaker 1: pressure of being cast upon a resource depleted island. So
Speaker 1: we we mentioned their flattened tail. That's one of the adaptations.
Speaker 1: Um and uh. And it's not like you don't find
Speaker 1: flattened tails and other lizard species, but this is clearly
Speaker 1: something that seems to help out there swimming. They also
Speaker 1: have a limited webbing on their feet, which I saw
Speaker 1: kind of a two different takes on this, and the
Speaker 1: literature is looking at. On one hand, there's the argument like, yeah,
Speaker 1: it's partially web feet, this is going to help them swim,
Speaker 1: but others say, well, the webbing is not that extensive.
Speaker 1: It maybe helps a little bit, but let's not overstress
Speaker 1: its importance. Well, I'm no marine iguana expert, but I
Speaker 1: it seems to me, at least when I've seen images
Speaker 1: of them swimming. It doesn't seem like they paddle with
Speaker 1: their feet much at all that I recall, but maybe
Speaker 1: they do sometimes. Something that everyone agrees on, though, is
Speaker 1: that their claws have become more powerful to allow them
Speaker 1: to grip the rocks and the surf during feeding. And
Speaker 1: this is certainly key because if you if you're observing
Speaker 1: one from the shore, or if you're looking at images
Speaker 1: or footage of them, or or if you're snorkeling and
Speaker 1: get to see one underwater. I did not get to
Speaker 1: see one underwater firsthand, but either way, when they're feeding,
Speaker 1: they're often in an area where you know, the surf
Speaker 1: is disrupting them and would make it difficult to feed
Speaker 1: if they were not able to hold on and latch on.
Speaker 1: And then of course when they get in or out
Speaker 1: of the surf, they're gonna need to keep from being
Speaker 1: swept up anyway. So yeah, they got to have those
Speaker 1: powerful claws to aid them. That's not an easy lifestyle,
Speaker 1: like crawling out of the surf onto rocks. I mean,
Speaker 1: think about how dangerous, how dangerous it would be to
Speaker 1: try the land a boat or even just swim up
Speaker 1: onto jagged rocks as the tide is coming in and out. Yeah,
Speaker 1: for sure. Um I was also Now this is something
Speaker 1: I was told by one of the guides in the
Speaker 1: Colabkos Island, who again are are very um knowledgeable of
Speaker 1: all of this. Uh so you know they're they're very
Speaker 1: quick to spout out all the scientific names of all
Speaker 1: the creatures you're looking at, and they're they're up on
Speaker 1: the latest find things and so forth. It was pointed
Speaker 1: out that they all utilize those sort of thorny spikes
Speaker 1: on their head and I almost hesitate to say face
Speaker 1: in order to loosen up the algae on the rocks
Speaker 1: by sort of rubbing their heads against it. It. And
Speaker 1: then it should also be noted we we touched on
Speaker 1: this earlier, but there's the whole regulation of their body temperature. Uh.
Speaker 1: And this is key because again the water is cold,
Speaker 1: and these are cold blooded animals, so they spend a
Speaker 1: fair amount of time basking in the sun. And the
Speaker 1: way this is certainly one way it was described to me,
Speaker 1: uh there, and it is backed up in the the
Speaker 1: paper those reading recently, is that in order to go
Speaker 1: into the water, they kind of have to power up,
Speaker 1: so like they're powering they're like on the on the
Speaker 1: beach or on the rocks, basking in the sun, kind
Speaker 1: of filling their batteries up all the way, and then
Speaker 1: when it's time, well then it's time. Now it's time
Speaker 1: to go into the water to forage for food, and
Speaker 1: they make that bee line, but it's only then, only
Speaker 1: only then, and they're not going to be thrown in
Speaker 1: early by some deranged Englishmen and and if something should
Speaker 1: get in their way while they're just gonna wait patiently
Speaker 1: for a little bit. But they're they've got a place
Speaker 1: to be. Uh, it is time to go into the
Speaker 1: water and feed. So it's a constant trade off of
Speaker 1: managing different energy resources in the body. You've got, you know,
Speaker 1: your your thermal energy, like you need to bask on
Speaker 1: the land to uh, to get your body temperature up,
Speaker 1: but then you need to go into the water to
Speaker 1: get food for your metabolism. And you're sort of just
Speaker 1: always trading back and forth between the two. Yeah. Now
Speaker 1: when they're in the water, their heartbeats also reduced from
Speaker 1: about forty three beats per minute on land to seven
Speaker 1: to nine beats per minute in the water, So that's
Speaker 1: also an interesting adaptation they have. And then, uh, this
Speaker 1: is another famous one that's a lot of fun to watch.
Speaker 1: You see this in footage every nature documentary that's covered
Speaker 1: marine iguanas. But both of the main varieties found in
Speaker 1: the four larger iguanas they have salt glands um that
Speaker 1: helped them process an abundance of salt should it be
Speaker 1: in the body. But with the with the marine iguanas,
Speaker 1: this of course is very visual because if you're just
Speaker 1: watching them lounge about, they're going to regularly appear to sneeze.
Speaker 1: They're not sneezing, they're blasting salt out of these salt
Speaker 1: glands that they basically blasting salt out of their nostrils
Speaker 1: as they lounge about on their rocks. And as they're
Speaker 1: doing this to making these cute little sneezing sounds or
Speaker 1: gross little sneezing sounds everyone to look at it. They're
Speaker 1: also kind of like crusting over the tops of their
Speaker 1: heads with this, you know, like white salt crystals, so
Speaker 1: you can tell like which ones haven't been on the
Speaker 1: in the water that recently because they have this kind
Speaker 1: of like salty look to their heads. They got the
Speaker 1: salt snot on their Yeah, you know, uh, this comes
Speaker 1: back to something else Darwin said. He was like, uh, there,
Speaker 1: you know, you can back them into a corner and
Speaker 1: you can catch them. They don't really bite. I don't
Speaker 1: think that's true, by the way, but he says they
Speaker 1: don't really bite, but they will blow salt out of
Speaker 1: their noses at you. Yes, I was. I remember reading
Speaker 1: this as well, because I was when we were in
Speaker 1: the glab because I pulled up the text, was reading it,
Speaker 1: and yeah, there is this um accusation that they're doing
Speaker 1: it defensively. Uh, and yeah, this does not seem to
Speaker 1: be the case. No, they they're just doing it. Maybe
Speaker 1: they're doing it. I guess. I guess it's probably this.
Speaker 1: I have no data on this, but I guess it's
Speaker 1: possible that if someone has is coming at them and
Speaker 1: backing them away, then maybe that does seem to incite
Speaker 1: a snort because they're about to move. But other than that, yeah,
Speaker 1: there's I've seen nothing to indicate that this is in
Speaker 1: any way of self defense measure. That's right up there
Speaker 1: with a in defensive vomiting. Yeah. Yeah, there's a lot
Speaker 1: of back and forth on that, right. I think we've
Speaker 1: discussed that, like, is a is like a vulture vomiting
Speaker 1: in order to like free up room, uh and you know,
Speaker 1: make itself lighter so it can take off and get away.
Speaker 1: Is it are offering a bribe to a scavenger that
Speaker 1: may be coming after them and decide to go for
Speaker 1: vomit instead of fighting a buzzard like they're they're various
Speaker 1: interpretations of that. As I recall now on the issue
Speaker 1: of marine iguana evolution, I was looking at another source.
Speaker 1: This was from Martin Wakelski in a two thousand five
Speaker 1: edition of the Royal Society paper entitled Evolution of body
Speaker 1: size in Galapagos Marine Iguanas. And I found this one
Speaker 1: interesting because the author here lays out one possible model
Speaker 1: for how the marine iguana is evolved. So, first of all,
Speaker 1: iguanas arrived according to this this um, this theoretical model
Speaker 1: in the Galapa goes perhaps ten to fifteen million years
Speaker 1: ago from South America via rafting, so swept out to
Speaker 1: see floating on some veget tasition and so forth, and
Speaker 1: then being cast on this strange island. And once they're
Speaker 1: there it becomes clear eventually here that in the inter
Speaker 1: title zone there's plenty of food for iguanas, but it's
Speaker 1: not on the land, it's the algae in the water. Uh. Initially,
Speaker 1: the iguanas are going to have to depend on low
Speaker 1: tides to get to the food. So the tide goes down,
Speaker 1: iguanas are are daring to to get down in there
Speaker 1: and go after the algae. And so there's going to
Speaker 1: but from there, that's where we're gonna begin to see
Speaker 1: the selection pressure towards larger bodies for thermal inertia and
Speaker 1: also the ability to anchor themselves in the surf, as
Speaker 1: well as these other adaptations that we mentioned, like the
Speaker 1: bigger clause ultimately the shorter snout as well. Uh, that's
Speaker 1: going to be a part of their their foraging behavior
Speaker 1: as they essentially like rub their their faces against the
Speaker 1: rocks to gnaw off the algae, as well as the
Speaker 1: like swimming morphological changes. Interest. Yeah, there's and there's there's
Speaker 1: actually a lot of a lot of work that comes
Speaker 1: out related to the marine iguanas, Like there's no shortage
Speaker 1: of papers. There's one from one that I was looking at,
Speaker 1: Cranial Anatomy of the Glabos marine Iguana by Paparella and
Speaker 1: calledwell in the American Association for Anatomy, and uh, they
Speaker 1: point out some of the you know, the key changes
Speaker 1: just to the head of the creature of viets evolution, uh,
Speaker 1: modified configuration of the snout and nasal chamber, increased muscle
Speaker 1: attachments in the temporal post orbital region of the skull
Speaker 1: and UH didn't, and also the teeth as well. So
Speaker 1: all this is coming seems to revolve around what they're
Speaker 1: feeding on and how they're feeding on it, and how
Speaker 1: that's affecting UH, just like the overall shape and even
Speaker 1: like the the muscles of the head. And I imagine
Speaker 1: they would make some guesses from this about how far
Speaker 1: back in in time the marine Iguanas had these evolutionary changes. Yeah,
Speaker 1: that one of the authors here, Paparella. I found this
Speaker 1: is actually I belief from another paper, but I saw
Speaker 1: this author saying that arguing elsewhere for an iguana colonization
Speaker 1: of the ancient Collapos Islands as far back as million
Speaker 1: years ago. And I think in this we're getting into,
Speaker 1: uh into into this idea of not only the the
Speaker 1: existing Galapicos Island, but these like pre existing Collapicos islands,
Speaker 1: the ones that, like you said, have now been lost
Speaker 1: and are submerged. Um Uh wrote that like this, we
Speaker 1: would have had like an initial dispersal followed by constant
Speaker 1: short range hopping from older to newer islands. So you know,
Speaker 1: they get a foothold on one place and then they
Speaker 1: can they can spread to these other islands much more easily.
Speaker 1: And then as new islands emerged, that opens up new
Speaker 1: places for them to be. And of course as old
Speaker 1: islands die away, then so do the populations of those
Speaker 1: islands or they you know, they're forced to disperse to
Speaker 1: newer islands. And Joe, from that that paper about the
Speaker 1: shape of their heads, I included at this wonderful image,
Speaker 1: this one. I think I didn't get this out of
Speaker 1: the paper itself, but this was I believe from a
Speaker 1: uh like a Twitter post by the American Association for Anatomy.
Speaker 1: It's out there if anyone wants to look it up
Speaker 1: for themselves. But uh yeah, you see very very high
Speaker 1: definition close up on both the head of the marine
Speaker 1: iguana and then also a comparison of the skull, which
Speaker 1: I thought was just very insightful looking at these, because
Speaker 1: you know, if it just looks, it looks very much
Speaker 1: unlike a lot of the lizard skulls you might see, like,
Speaker 1: like glancing at it, you might not even think of
Speaker 1: it as a lizard scull, mean, doesn't look like a
Speaker 1: human skull or anything. Um, it's distinct, but you can
Speaker 1: clearly see like the changes that have taken place here. Yeah,
Speaker 1: the blunt snout and the density of it, I mean
Speaker 1: almost you can imagine it being more of a turtle skull.
Speaker 1: Or again, I mean it looks kind of like Godzilla. Yeah,
Speaker 1: it's like Godzilla. And I like how they kind of
Speaker 1: have you see, especially in close up that like these
Speaker 1: there's real sense of iguana lips, you know. Yeah, you
Speaker 1: also get a really good look up inside the nostrils. Yeah,
Speaker 1: this of course is a specimen. This is a dead
Speaker 1: iguana that Joe and I are galking at here. Um,
Speaker 1: but still beautiful specimen. But yeah, the Marina iguanas are
Speaker 1: our special creatures. And I don't I think I don't
Speaker 1: even have to tell anyone this. This is not new information. Uh.
Speaker 1: There have been so many documentaries that of course have
Speaker 1: covered the Galakos Islands that have caught brilliant footage of them.
Speaker 1: They are a standout species that they've been highlighted in
Speaker 1: in various shows over time, or you've you've no doubt
Speaker 1: seen articles about them or see them popping up in
Speaker 1: the lists. So so yeah, nothing nothing new in me
Speaker 1: saying that these animals are great. But but like all
Speaker 1: these things, you have if you get to see them
Speaker 1: in person. If you have that chance, take that that opportunity,
Speaker 1: because they're they're pretty remarkable. I would like to see
Speaker 1: the iguana puppy pile. Hey, we haven't even touched on
Speaker 1: the most famous reptiles of the Galapagos, and I think
Speaker 1: we're gonna have to do that in the next episode.
Speaker 1: That's right, the Galapa goes towards us. We're gonna come
Speaker 1: back in the next episode of of this journey to
Speaker 1: discuss uh, these fabulous creatures. I mean, it makes sense
Speaker 1: that they'd come in second. They are slower, but they're
Speaker 1: they're very remarkable in their own way, So be sure
Speaker 1: to come back for that episode. In the meantime, we'd
Speaker 1: love to hear from you if you have thoughts about
Speaker 1: Marine iguanas um you know, firsthand or documentary based. If
Speaker 1: you're a resident of of Ecuador the Glavacos island, certainly
Speaker 1: we would love to hear from you on all of this.
Speaker 1: If you want to hear more Stuff to Blow your Mind,
Speaker 1: I'll just remind you that core episodes of the show
Speaker 1: publish on Tuesdays and Thursdays in the Stuff to Blow
Speaker 1: Your Mind podcast feed on Monday's We Do Listener Mail,
Speaker 1: on Wednesday's We Do a short form artifact or monster Fact,
Speaker 1: and on Friday's We Do Weird How Cinema. That's our
Speaker 1: time to set aside most of the serious science and
Speaker 1: so forth in just talk about a strange film. Huge
Speaker 1: thanks to our audio producer Max Williams. If you would
Speaker 1: like to get in touch with us with feedback on
Speaker 1: this episode or any other, to suggest a topic for
Speaker 1: the future, or just to say hello, you can email
Speaker 1: us at contact at stuff to Blow your Mind dot com.
Speaker 1: Stuff to Blow Your Mind is production of I Heart Radio.
Speaker 1: For more podcasts for my heart Radio, visit the iHeart
Speaker 1: Radio app, Apple Podcasts, or wherever you listening to your
Speaker 1: favorite shows.