Welcome to Stuff to Blow Your Mind, production of iHeartRadio.
Hey you welcome to Stuff to Blow your Mind.
My name is Robert Man and I am Joe McCormick. And today on Stuff to Blow Your Mind, we're going to begin a series of episodes on the theme of being upside down and if you are wondering, yes, this is another baby looked at Me episode idea. I started thinking about this because of my three year old's fondness for dangling upside down. She really likes to ask us to hang her upside down and then to be brought face to face with other family members while she's hanging
upside down. So like when she sees them, I guess, I don't know exactly what's so funny about it, but she descends into like cackling madness, and it's kind of like, can you believe this? This is absurd?
No, No, this is totally understandable. And you know, even as an adult, there'll be times where I don't know, I'll be in the right position. Maybe I'll be, you know, reclined on the floor for a yoga class or something, or just in my living room and you'll imagine the ceiling as the floor and what it would be like
to be up there. Or an even more terrifying one is if you find yourself out either on like a clear starry night or even a really clear blue day, and imagine yourself detached from the gravity of the planet and ascending upward, falling upward, that sort of thing. You know, it can the wildness of the concept, once you sort of like break through your everyday mundane blocks to it can still be almost overwhelming.
I feel like you've mentioned the falling upward into the sky daydream before. This is a common thing for you.
Yeah, I mean it's not. I wouldn't say it's like a central anxiety point or or even like a recurring dream so much. But I don't know. There is something about like a really clear day, especially a really clear like blue sky day, and sometimes a very clear, star
filled night that kind of taps into this notion. It's kind of like if you stop and try to remind yourself to breathe, which, to be clear, can also be a very grounding and beneficial practice, but you know, sometimes you're like, oh, I'm breathing now, and then you can kind of like sort of freak out about about making sure that you're breathing, you know, taking something that is just a basic background process of your life and turning it down his head.
Yeah, or if you like, think about your heartbeat too much, it can make you start feeling like you wonder is something wrong with it?
Or yeah, yeah, that's sort of.
So before we get into the pulp of today's episode, I wanted to start us off with a bit of poetry to establish the upside down mood. And I was looking around for some literary examples to kick things off here, and I actually found what I thought is a great one, and it's going to take us straight to Hell. So I want to talk about a very weird, actually scientifically loaded and also I think very funny scene from the Divine Comedy. So this is going to be from Dante's Inferno,
Canto thirty four. And the scene we're going to be talking about is right before the end of the first book of the Divine Comedy, right before the end of the Inferno, So it's going to come at the tail end of Dante's journey through Hell, before he emerges again to face the mountain of Purgatory.
Yeah, and reminder for listeners who are maybe not that familiar with this work or haven't heard us talk about it? In a bit. Inferno is book one of three in the Divine Comedy of Dante Aligary, who lived twelve sixty five through thirteen twenty one, poet scholar, really almost the sort of polymath exile of Florence. It's a narrative poem, and theor stands as one of the greatest and most important works of not only late medieval Italian literature, but Western,
if not global literature as a whole. It's notable for a number of reasons. It was written in Italian rather than Latin, it popularized and shaped the concept of Christian purgatory, and in general, I would argue that the text still stands as a highly readable if you have a good translation, good notes, and you know and interest in reading it.
Notes are very important because there are a lot of things in it that don't make any sense at all unless you get like historical context explaining them.
Yes, you are, in some respects not the intended reader by the stretch, but once you get into the notes and into that world is very enjoyable because it's essentially a crash course in Dante's entire world. His faith, his feuds, his loves, his trials and tribulations, his fascination with just a host of philosophical, historical, mythological, and even scientific topics.
Yes, and you've really you get to find out who Dante's mad at. Sometimes they pop up in hell.
Yeah, I mean I was thinking about this. I was like listing all this out, these things that the text is, and I was thinking about lyrics to a DMX track, and I was like, Dante was kind of like a rap star of his age, you know, oh yeah, you know, you know, almost kind of getting into distract territory at times in.
Absolutely work, Yeah, putting his enemies and like showing their wickedness and their punishments. But also, yeah, there is a lot of genuine wonder in there as well. And so well, let's get right into the scene and then we can talk about the implications after I do a reading. So in this scene, Dante he begins as a lost traveler. He's wandering in the Selvoskura. He's wandering into dark wood, and he meets the soul of the Roman poet Virgil, who can't go to heaven himself because he was not
a Christian. He lived before Christ, but he lives in limbo alongside other figures, many of whom are known as the Virtuous Pagans. So he's in limbo with these people who don't really belong in either Heaven or Hell, people like Homer, Socrates, Ptolemy, and saladein and so Virgil meets Dante and he leads him on a tour of the nine circles of Hell, going down and down all the time, deeper and deeper further into the bowels of the earth. And so together eventually Virgil and Dante reach the very
bottom of Hell, where Satan himself lives. Depicted as a giant shaggy beast, almost a winged bigfoot, but I think like a thousand feet tall, So a gigantic shaggy beast, encrusted with ice, with three heads, leathery wings like those of a bat, and forever. Satan is described as forever weeping tears that freeze into ice and are then frozen further by the flapping of his wings. So the flapping of his wings generates a wind that freezes the center
of Hell. It's almost like in trying to escape his own suffering by flapping his wings and in the expression of his anguish, he further creates the freezing conditions and the misery of the very core of hell. So he's down there flapping the bat wings, crying these frozen tears, drooling blood from his three mouths, and then in his three mouths he's described as eternally gnawing on the damned souls of Judas Iscariot, the betrayer of Christ and the Gospels,
and Brutus and Cassius, the betrayers of Julius Caesar. These are the three figures that Dante the poet sort of considered the worst traders against God and country in human history. A lot of modern readers really don't understand very well why Brutus and Cassius are there. That seems like man, that's really giving them an important place. But it makes more sense if you understand the Dante medieval or late medieval Italian mindset of like really valorizing the Roman Empire.
It's just like the Roman Empire was like the best there ever was.
Yeah, again, you have to keep in mind that is it is a very personal work in so many respects as well, and like this is Dante's take on it. It's like if someone elsewhere to where to say reserve the third spot in Satan's mouth for say Yoko Ono saying like, how dare she? How dare she allegedly break up the Beatles? You know, that is one of the greatest strggies of all time. And then in your mind, yes, she belongs to this, this place of infamy. So there's
maybe a little bit about that going on. But also yes, I think it's also essential to realize how much weight these traitors had in the public mind and in the culture at that time.
I've got some love for Yoko.
Oh yeah, I don't speak to any personal animosity there.
Right, but I understand what you're talking about.
Yeah, it's been a common cultural reference point.
For death rides. But so anyway, in the story, after reaching the lower depth of the pit, Virgil and Dante they have to continue going. But they what are they going to do? Like, they've reached the bottom here, Satan, so they have to continue their journey by crawling directly down the devil's huge, nasty body. So here I'm going to begin reading from Kanto thirty four. This is the Longfellow translation, and in this selection, Dante starts off talking
about a hymn. That's talking about Virgil his guide. So the poem goes as seemed him good. I clasped him round the neck, and he the vantage seed of time and place. And when the wings were opened wide apart, he laid fast hold upon the shaggy sides. From fell to fell, descended downward, then between the thick hair and
the frozen crust. When we were come to where the thigh revolves exactly on the thickness of the haunch, the guide, with labor and with hard drawn breath, turned round his head where he had had his legs, and grappled to the hair, as one who mounts, so that to hell. I thought we were returning. Keep fast thy hold, for by such stairs as these, the master said, penting as one fatigued, we must perforce depart from so much evil. Then through the opening of a rock he issued, and
down upon the margin seated me. Then towards me he outstretched his wary step. I lifted up mine eyes and thought to see Lucifer in the same way I had left him, and I beheld him upward hold his legs. WHOA. So this part catches a lot of readers off guard, like what is going on here. Dante and Virgil, they are climbing physically down the hairy, beastly body of Satan, who's like a giant against a giant, three headed, bat
winged bigfoot. They're crawling down him and at the moment they get to like his hip or upper thigh area, sort of around the side of his butt. With some exertion, Virgil, who Dante is clinging to, rotates his body around, so Dante so like his head is pointing down now, and he grabs hold of the devil's shaggy fur, and Dante's confused. He's asking, wait, what's going on? Are we going backwards now? Are we going back into hell? But Virgil bids him to continue, so they crawl on into a tunnel in
the rock. And when Dante looks back at the devil now, he's amazed because it seems like the devil flipped upside down. Something has changed. Now he's looking at Satan and Satan has got his giant gamey legs sticking up with his head pointed down? So why is the devil flipping upside down? But we will actually get a scientific explanation, at least as far as the as far as things were understood
by the natural philosophy of Dante's time, writes quote. And if I then became disquieted, let stolid people think, who do not see what the point is beyond which I had passed, Rise up, The Master said, upon thy feet. The way is long and difficult, the road, and now the sun to middle tierce returns. It was not any palace corridor where there where we were, but dungeon natural, with floor uneven and unease of light air from the abyss.
I tear myself away, my master said I, when I had arisen to draw me from an error, speak a little. Where is the ice? And how is this one fixed thus upside down? And how in such short time from eve to morn has the sun made his transit? And he to me, thou still imaginest thou art beyond the center where I grasped the hair of the fell worm who mines the world. That side thou wast so long as I descended. When I turned to me, thou didst past the point to which things heavy draw from every side.
So there is an explanation given here. Satan did not move. Satan did not flip upside down, while crawling down Satan's body, Dante and Virgil passed through the very center of the Earth, which, in the Aristotelian cosmology that Dante believed in, is also the center of the universe. So the point to which all objects with weight what Aristotle called the heavy objects like solids and liquids, the point to which all heavy objects are pulled. So nothing in their surroundings had actually
changed position. All the stuff was in the same place it had been, but for Dante and his guide, down suddenly became up and up became down.
Uh.
And I think this is such an interesting almost science fiction plot element to include in a tail from the early fourteenth century. It feels like something you know, it's not. It's not science fiction in the sense of speculating about the future or about technology, but it is incorporating a leading scientific understanding of the world at the time to explain the mechanics of a fantastical scenario.
Yeah, yeah, it's you know, it's like if we're trying to imagine what it would be like to crawl through the center of a Torus space station, you know, one that's spinning like a big wheel. You know, a very similar situation with perceptions of gravity, artificial gravity caused by the spinning might be observed. And since we don't have a space station like this, and we also do not have a world like this with Satan at the center
of it, we can crawl up and down. You know, we're just using our understanding of the natural world to put ourselves in that place. What would it be like to do that?
Yeah, using inference from our best understanding of physics to describe this fantastical scenario.
Yeah.
I should point out that this is not the only place in the Divine Comedy where Dante has this kind of science fiction style attention to weird physical realities. On several occasions he engages seriously with scientific theories of his day, with like astronomical theories and stuff about how light works and all this, and he applies these these understandings to his fantastical settings. Dante was a bit of a of a science nerd, though they wouldn't have called it science at the time.
Yeah. Absolutely, There's so many different places, like the one in particular that I always come back, and this is a small one, but just about how what happens when or freezes it expands? Uh, you know, there's a place where they're talking about the damned or frozen. There that the lake at the in the lake at the center of the world, and their their eyes are looking upward, their their sockets pool with tears, the tears freeze and
then expand painfully in their eye socket. You know, So little things like that, you know, it's you know, it's he's not, you know, positioning in some sort of impossible realm, but he is certainly applying his understanding of the natural world to these little details.
Yeah. So I think there are a number of things about this little passage in the Inferno that are very interesting, but they have different implications for Dante than they have
for us. So again, Dante believed the Earth was the center of the created material universe, with the domains of the planets and the stars existing in these concentric spheres extending out from our planet, and thus the center of the Earth was sort of the center of the center of everything that was material and created, and that's where
Satan is. So that kind of seems weird, doesn't it that a fourteenth century Catholic like Dante would situate Satan, the Prince of darkness, father of lies, at the center of everything, the heart of all physical reality, seems like a kind of privileged place to put the worst possible being, right.
Yeah, yeah, yeah, when you start thinking about like the pure cosmology of the thing, like this is the center of everything, and this is where the great enemy is.
But if you understand Dante's cosmology, if you understand his model of the universe, it actually makes a lot of sense. Because Dante believed that God himself dwells in or I guess maybe even beyond what's known as the empirehean it's this area that's the highest heaven, or he might say beyond the highest heaven, actually above and somewhat outside the
concentric spheres of the created universe. So to be at the center of the earth and the center of the universe is actually to be as far as one can possibly reside from God's light. So throughout the Divine Comedy, Dante repeatedly compares sin to weight and grace to lightness. So sin and evil and wretchedness all sink, They physically sink towards that central point to which all heavy things are pulled, and redemption and holiness cause things to rise,
to rise up through the heavens. So given that, it actually makes a lot of sense that for Dante, Satan is the center of the universe. That's the worst place you can be.
Yeah, And it makes sense given the trajectory of the entire Divine comedy, which again is starting in the mundane world, and then you descend into Inferno, go to the very bottom of it, then crawl your way up to the center of the Earth. You go up to the mount of Purgatory on the other side of the world, ascend to the top of that, which takes you to the terrestrial Eden, and then from there you venture into the paradise, into the realm of heaven and God and so forth right.
But the other cool implication of this passage is that, given Dante's cosmology, once the character Dante and Virgil crawl down the devil's disgusting bigfoot thigh, they have not only crossed through the center of the planet Earth because of the cosmology, they have crossed to the other side of everything. So that's kind of fascinating too. It's like the midpoint of the universe and they've gone to the other side.
But there's another interesting implication of this passage. If you apply our modern, more Copernican influenced view of the cosmos, in which we know that there is no good reason to think that the center of the Earth, or in fact any point in space, is the center of the universe. Astronomers and physicists now generally believe that there actually is no such thing as a center of the universe. And it's not just that we don't have a way to
find the center. It's that when you zoom out far enough, the universe appears to be the common expression is homogeneous and isotropic, meaning it looks basically the same from all locations and in all directions, and it's expanding equally in all directions. So that's kind of hard for us to understand intuitively, because if you like, you can't really picture
a three dimensional space without a center point. Like if you imagine the volume of a cube or a sphere, there is a middle point in there, somewhere inside the middle there is a point that's furthest from all the boundaries. But our best evidence indicates that the real universe, the universe at large, is not like that. No direction you move in can bring you closer to or further from the spatial boundaries, and in fact, there probably are no
spatial boundaries. So that sounds kind of counterintuitive because how can a space not have any boundaries? But this point is pretty interesting. There are several different, still possibly viable models for the large scale geometry of the universe, but
none of the standard ones have spatial boundaries. So, based on our best evidence from things like the cosmic microwave background, the universe is either infinite in spatial dimension, meaning there are no boundaries and you can just go forever in any direction, or the spatial volume of the universe is finite, so it's not infinite, but it's closed meaning A common analogy used to explain this is if you think about the two dimensional surface of a three dimensional sphere, so
like the skin of a balloon or a ball. If you imagine an ant crawling on the surface of a ball, it's not infinite, like there's only there's a limited area that it can crawl around, but it can never reach a boundary. You can just keep going forever in any direction there is no boundary. So this analogy isn't perfect, but it does capture the idea that, like the surface of a sphere, where the area is finite, but there's
no outer boundary. The universe itself is possibly finite, but without a boundary, and is kind of like the surface of a higher dimensional space.
Okay, certainly hard for us to envision. It's not the sort of environment that we evolve to make sense of in our own mind totally.
But again the point is our best models of the universe, the ones that best conform to the evidence and are subscribed to by the most physicists and physical cosmologists, they don't have a center point, and they don't have boundaries. They're either infinite or you can or they're finite but closed, and they don't boundaries either way. So, given our modern view, the interesting physical thing about this part of the poem is actually how it highlights that up and down are
merely a matter of perspective. In Dante's cosmology, there is an objective, universal up and down, but in our universe there is no universal or objective up and down. Up and down are sensations we feel based on our relationship to the nearest, strongest gravitational attractor. So you change your orientation to the attractor and the directions of up and down change as well, which is what they would have
done going through the center of the Earth. Also, there is the change in our understanding of gravity that makes this passage interesting. You know, in our like post Galileo post Isaac Newton world, we know that gravity is not the tendency of heavy objects to sync to the center of the universe, as Aristotle thought, putting aside Einstein's refinements of functionally, gravity is the mutual attraction of mass to mass.
So there's actually nothing gravitationally special about the Earth, or about planets, or even about the center of a planet. And this can really be illustrated by applying what we know now about gravity to the idea of going through
the center of the Earth. We now know that if you were really somehow able to crawl down to the center of the Earth, and you can't do that because of the pressure and everything, but what you would actually do, what you would actually experience if you could do that, would be decreasing gravity as you get closer and closer to the center point, closer to the bottom of Hell.
And once you finally hit the center of the Earth, you would experience microgravity, or effectively zero gravity, because the mass of the Earth attracting you would no longer be disproportionately below you. It would now be roughly equal in every direction all around you. You'd be equally attracted to
mass in all directions, you know, all around. So if anybody I was thinking about this, and it was like, if anybody ever wanted to make a weirdly pseudo scientifically accurate movie version of Dante's Inferno, they could have Dante and Virgil becoming lighter and lighter as they approached Satan's body, and then finally when they're going through, you know, going by Satan's butt here they float in the air like astronauts on the space station.
Oh, or like Charlie and Grandpa after they had the fizzy lifting drink right exactly.
Yeah, so that would be somewhat physically accurate if it were the center of the Earth. Though, if we're going to be nitpicky, this wouldn't really work either because they'd be under immense pressure and you know, so like a cavern like this could not exist. But anyway, for the rest of the series, I propose we we we spin around on Satan's wooly haunch and and kind of crawl into the upside down of everything.
Yeah. Absolutely, And I want to acknowledge here some of you are also enjoying video with this episode you're watching on Netflix. Netflix, of course, is also where Stranger Things is, So, you know, we should acknowledge that the idea of the upside down in our modern usage has been greatly affected by this show, where the upside down is like a shadow realm, an opposite world where things are creepy and dark.
And you know, it wasn't the first property to explore this kind of concept, but it certainly is a has been a highly popular one over the past several years.
I don't remember from I only saw the early I think maybe the first two seasons, but I don't remember. Is there actually anything upside down about it? Or is it more just kind of an alternate dimension.
Alternate Well, you find out more about it. It's a show proceed I don't want to spoil anything, but early on it's all they also use, like, you know, talk about like a flea on a wire and as a way of like moving back and forth between these two dimensions and so forth. But you know, you can, I guess loosely think of it as just a dark, creepy world. That is the reflection, you know, it's through the looking
glass compared to our world. But I wanted to briefly mention the idea of a phrase that I came across, and I think I'd encountered a few times in the past, the idea of an upside down kingdom, which initially brings to my mind the idea of like, you know, sinister elves living in some sort of a strange world that's like, you know, on the flip of our of our reality, you know, like tails from the dark side sort of energy going on here.
But it's been something from Gulliver's travels.
Yeah, yeah, But you know, since we're already dealing a little bit with Christian themes, and since we're so close to Easter, I think it's worth acknowledging the concept of the upside down kingdom and Christianity. So this is a kind concept with biblical roots in the teachings of Jesus, you know, the first shall be last blessed, or the poor and so forth, but then with specific roots to
a nineteen seventy work. By nineteen seventy eight work by sociologists and theologian Donald Crable, who wrote a book with this title arguing that from a sociology standpoint, Jesus argued for an inversion of the existing social structure and upside down kingdom, essentially turning everything topsy turvy, where people in positions of power serve rather than rule, the lifting up of social outcasts, the loving of one's enemies, the sharing of wealth, and ultimately, in the case of Jesus, the
giving of one's life to save others.
Oh okay, Yeah, so the idea, the phrase upside down kingdom is not itself used in the Bible, but that's an interesting way of describing, Yeah, an attitude that's there in a lot of the preaching of Jesus and the Gospels, which is, in a way, I think you could say can continues in a pre existing tradition of apocalyptic preaching from Judaism, about the idea that many of the rulers and powerful and rich people in the world have gotten to the place they are by evil, and thus the
you know, their rich, their wealth and their power is an expression of evil. But the powerless and the poor will one day be brought up to overcome them. You know, there will be an inversion, a righteous inversion, And I think maybe you could say that the preaching of Jesus to some extent, extends that beyond just the sociological power structure and into common moral understandings. The idea of having love and mercy for people who previously would have been morally condemned.
Yeah. Yeah, and of course love your enemy thing is one that is difficult for any of us to struggle with. But yeah, I think it is interesting to think about, like an inverse world, an upside down world could also be considered not a dark world at a righteous world. Like maybe it's inverting things that have become twisted in reality.
Yeah, I mean I think that is that is like the apocalyptic Jewish idea.
Yeah.
Now, at this point, though, let's move away from the religious world and think more about the natural world again. When we think about the upside down and the natural world, there's one particular type of organism we tend to think about, and it's a superstar when it comes to living upside down. We're talking about bats. Oh yeah, we've all seen images, footage,
artistic representations of this. Bats hanging inverted from limbs, from the roofs of caves, from other structures, and hanging by their little toes.
We actually just did a series of episodes about Carchner caverns in Arizona, which you recently visited, and that is a major bat roosting cave. I assume the bats in there primarily do hang by their toes filing.
Yeah, absolutely they do. Not. All species of bats actually hang inverted. The vast majority do. The exceptions we're talking about, they're like seven species exceptions out of a good like fifteen hundred recognized bat species. Most of them do hang. But you have examples like Madagascar sucker footed bat. This particular variety of bat clings head up to smooth surfaces, the smooth surfaces on leaves, using specialized pads on its
wrists and ankles. So some sucker bats are the main outliers, but the vast majority of other bats definitely hang by their toes. And of course this is just one of the ways that bats are a wonderful inverse to our way of living. You know, we think of bats as creatures of the night, while we are creatures of the day. For the most part, we think of them roosting in caves within the earth while we live above the ground. We stand upright on the ground, while they hang inverted.
We walk, they fly, And while we famously can never quite put ourselves in the mindset of a bat or know what it is to be a bat, we do this anyway. You know, when contemplating any other species, we imagine what would it be like to do that, and especially when it comes to considering their inverted lifestyle, this sort of thing results in a basic error in our understanding because we think about what it would be like for us to hang like that.
You know, I think I would suspect even the strongest ballerina in the world cannot hang for very long by their toes.
No, no, I would be very surprised, shocked even if I saw even a single example of someone hanging successfully by their toes. We can, of course hang by our fingers in our hands, and most of us have done this before, either at a push up bar or maybe you know, playing on the monkey bars or some other kind of gymnastics equipment, maybe you know as a as a serious gymnast, even but it's very much an ability we have to activate that we have to train and
focus on. And your fingers are going to get tired. Your fingers and hands are going to get tired from all of that gripping.
And it's weird that it takes us so much effort because in a way, we're at least our ancestors are somewhat evolved for this. I mean, there is a dedicated term in zoology for the type of locomotion that you see certain primates using to swing from tree branches. They hang from the tree branches. The swing is called braciation.
Yeah yeah, yeah, so you know, yeah said, certainly there are some some some other superstar hangers out there when it comes to hanging by by hands and feet. But when we approach the idea of the bat, we can easily imagine bats having to exert the same force that we do. But it's actually quite the opposite with them. They can hang with minimal effort and can do so for extended periods of time. Young bats can do it
at birth. So what's going on here is they have what's called a tendon locking mechanism or TLM, which can also be found among birds. Simons and Quinn, writing in the journal Mammalian Evolution back in ninety four, describe it as follows. In bats, this mechanism typically consists of a patch of tuberculated fibrocartilage cells on the planter surface of the proximal flexor tendons and a corresponding ply caated portion of the adjacent flexer tendon sheath.
Okay, now I do not talk about that anatomy to make sense of that.
Yeah, don't worry if that did not compute, because we're about to get to the important part. They continue. The two components mesh together like parts of a ratchet, locking the digit in a flexed position until the mechanism is disengaged.
Oh okay, so I see. So it has a essentially a lo blocking mechanism that does not require continuous muscular effort to keep the grip closed.
That's right. In fact, it has to be unlocked in order to let go. So it's the It is the complete inversion of the way we think about hanging on to something. You know, Like anytime you're watching an action film, you know, and somebody's hanging from the edge of a cliff or a skyscraper, it's like, keep hanging on, keep exerting pressure. For the bat it's like, just don't actively disengage from your hang. And so this allows them to
just give into gravity and hang to sleep. For extended periods of time in this position to hibernate in this position, and the lock will even stay in place after death.
Oh so the bat can die, but it just stays. Do people ever find bat skeletons still hang like defleshed but still hanging.
That's a good question. Maybe I have to look back into that for the next episode. I know you, I mean, certainly you. It's not like all bats die and then hang like bats die and fall or they you know, you'll find dead bats on the floor of caves, and there are in some cavern environments there are scavengers who take ready advantage of that.
But wait a minute, So I've got a question, why do bats hang in the first place? What advantage does it provide them to dangle upside down as opposed to I don't know, just crawling into a hole or doing what you know, sitting right side up like most mammals.
Yeah, this is a great question and one that we often don't even think about because this is just what bats do, right, We don't necessarily think about why they do it. I guess one of the real obvious answers, and probably the first one to come to mind, is is one that just makes sense to us floor dwellers when we look up at the ceiling. The ceiling is safer if you can get up there. Well, there are a lot of predators that cannot follow you or cannot
easily follow you up there. So it seems like, you know, bats can access it seems like a good place for them to hang out. Again, they can fly. But there's more to it than that. Bats are for the most part, all in unflying. Even bats that have adapted to ground predation and are pretty good about crawling around, they still have what you might think of as a morphologically pure flyers build. You know, everything about their body has evolved
for flight. They evolved from our boreal mammals, you know, more than fifty million years ago, and a lot of trade offs had to be made for these creatures to take to the sky like this, not just to glide through the air, but to fly through the air with true powered flight.
Well, I mean, one thing I would imagine is that by turning their fore limbs into wings, they have sacrificed a lot of alternate utility that can be made of four limbs.
That's right. You know, we've touched on this before. But when you look at the wing of a bat. The wing is basically a hand. It's like a hand that has evolved into this wing. And so you know, this is one of one of the reasons they're going to have trouble moving around.
Uh.
If they try, if it even in intern de bat's mind somehow to like walk like a human and to interact with the world like a human, they would encounter problems here. Uh yeah, yeah, and some of them some
do you know, we'll get through here. But I was looking at an article on the website of the Bat Conservation International Group, and this articles by one Kristen Pope, and they point out that birds, for example, one of the things that birds have adapted, one way that they've evolved for flight is that they have the you know, famously hollow bones. Bats do not have hollow bones, but they have light, long bones and this includes their femurs.
And this means that their legs can't withstand compression stress which would come with standing up again, if it, if it all were even an option for a bat to stand up. Also, the again, the nature of the bat wing makes it difficult, makes it difficult for them to do something other than crawling about on the ground. And you know, again, this isn't to say that bats can't awkwardly move on the ground or even hunt there as
in some species, but it's not their strong suit. A bat on the ground in any situation is going to be at its most vulnerable.
Right So a bat can crawl, but it's not crawling specialized in the way like a scurrying rodent is.
Right right now. The other great thing about hanging from something, be it a tree branch or the roof of a cave, is that this is just a great position from which to take to the air. Oh yeah, so again it comes back to flying again. But most bat species can take off from the ground. Being on the ground again puts them at a great disadvantage, and they absolutely have to possess many of them have to possess some sort
of ability to take off. Some like vampire bats, are apparently especially good at it, like hurling their little bodies into the air, you know, maybe a little awkwardly at first, but they get up there, then they start flatt and then they're able to move.
On.
Vampire bats as well generally good ground movers as well, because they need to be able to discovery over the ground a little bit and also even over the bodies of their prey. Only your larger mega bat like fruit bats can't pull off taking to the air from the ground, and this is due to their size. They have to crawl, climb, drop, and fly. But of course generally they're living in areas that have a lot of trees, and you know, this is achievable for them if they find themselves in this situation.
And these again are only going to be your mega bat fruit bats, not all fruit bats, and with all the but with all bats, the drop is still the most energetically effective way to transition to fly.
So basically all bats would prefer to drop from above to flip into flight, but some, like I would imagine the megafruit bats. Would this include like the flying fox.
Yeah, the biggest of the flying foxes for example.
Yeah.
Yeah, And so.
They they would have to climb up a tree and get on a branch in order to go into flight. That's amazing, Yeah, they almost like I'm thinking of how you know rockets need like some infrastructure in order to get going. Yeah.
Yeah, it's like where you know, you can think of examples too of like how are you going to take off on a glide, or you take off from the top of a sand dune, or the or the or the indention between the sand dunes. Obviously you want to go to the top, right, It makes the most sense energetically.
So are you okay if I do a tangent on another mammal that dangles upside down?
Oh? Yeah, this is a great one.
So bats are not the only mammal adapted to living upside down, or at least spending a significant amount of time upside down. Another example is the tree sloth. So quickly, I'm going to mention a couple of sources on what I'm talking about here. One is a paper for I'm the journal Biology Letters twenty fourteen by Rebecca Cliff, Judy Avy Arroyo, Francisco Arroyo, Mark Holton, and Rory Wilson, called
Mitigating the squash Effect. Sloths breathe easily upside down. And I was also reading about this in a twenty fourteen blog post published on the website of the Sloth Conservation Foundation summarizing and contextualizing this paper. This blog post was unsigned, so I don't know exactly who the authors are, but it talks about the paper I just mentioned in the first person, so I'm assuming it was one or more of the authors of that paper. So there are two
still living genera of tree sloths you have. Oh and I actually did not look up how to pronounce these genera. Rob If you know anything I'm saying here is wrong, correct me. You've got the three fingered sloths, which are called bradypus or bradypus, and then you've got the two fingered sloths, which are called a coloe or cho loopus. Yeah.
I can't really chime in on either pronunciation, but I will mention briefly that I do. I've always loved that you can say sloth or you can say sloth sloth. In my household, we kind of have taken to saying sloth merely out of amusement and probably from watching, you know, certain documentaries.
Is sloth not the uh? I don't know. To bring it back to Dante, the way you would pronounce the sin, the older sin and the medieval sins, Yeah, yeah, I guess so. So true to their name, sloths are famous for being incredibly slow moving, and the slowness is not just in their locomotion. It goes all the way down to their metabolism and digestion. In some cases, it can take a sloth or a sloth about a month to
fully digest a meal, and they mainly leave. So you know, leaf goes in, it might take a two weeks or up to a month before the same leaf passes out, finally passes all the way out, uh, and they will go. They will go often a week in between trips to the forest floor to urinate and defecate, so you know, seven days in between bathroom breaks. Very slow moving, slow digesting, usually carrying a lot of poop and pee on deck.
If you look up photos of a sloth in the trees, you will often see them hanging upside down in one sense, upside down in the quadrupedal mammal posture, so they'll have the body horizontal beneath a tree branch, hanging by the legs and kind of similar to what you were talking about with the bats, Sloths I was reading are able to grip branches easily and without exertion because their feet are relaxed in the closed position with the toes gripping something.
So this is kind of different than what you think about with your hands, where you sort of have to flex in a way to close your fist. Sloths have to flex to have to flex their muscles to open their grip and not close it. So gripping is easy, that's the relaxed position.
Yeah, with both sloths and bats. It is just so hard for us to imagine to put ourselves in their bodies, because this nature of our grasp is just it's just such a part of our everyday, continual existence that it's just hard to imagine it another way, even though we're just talking about a rather seemingly simple inversion of the way things work. You know, it's easier for us to imagine living on the ceiling than it is to have a grip functionality like this.
Well, yeah, because at least you yourself have probably at some point, at least in childhood played around hanging upside down, so you can imagine that. But you can't. But it's harder. You have never had the experience of having different anatomy and different neuro anatomy than you do. Yeah, you know, so it's just like, you know, you can't really imagine it as clearly, at least not from exiod.
It's like trying to imagine what if you could sense the electromagnetic field.
That's sort of yeah. But the authors here mentioned that if you observe sloth behavior, you will not only see them upside down in this sense of hanging upside down with the body horizontal. They say tree sloths actually spend a lot of time hanging upside down in the vertical sense, so hanging from their toes with the head pointed down. Now, why would they do this, Well, it's not just for fun.
This is metabolically important behavior. I was reading an interview with Rebecca Cliff, the lead author on this study, and she talks about how sloths really want specific kinds of leaves. You know, the leaves they eat off of trees. It's tough food, you know. It's they're tough, and they're fibrous, and they have a lot of unpleasant chemicals in them. So these leaves are what sloths are specialized eat. But they're not you know, easy going food. It's a tough
life living on those kind of leaves. And Cliff says that they really want specific kinds of leaves, most of all the tender, young, freshly budded leaves that grow on the very outer tips of tree branches. And she says these leaves are easier for the sloth to digest, and
they tend to have a lower concentration of toxins. So obviously, the leaves on the very tips of tree branches can be harder to reach than leaves further back on the branch, because if you imagine climbing on a tree to try to reach the leaves, the outer tips of branches tend to be delicate and not able to support a lot
of weight. So to get into position to access these branch tip leaves throughout the tree, sloths have to spend a lot of time hanging vertically upside down to reach them, so that's head pointed to the ground, and they can be like this for hours and hours. But there is a problem if you have ever hung upside down yourself
for an extended period of time. Might be fun at first, especially if you're a kid, but you probably know from experience that inverting the body pretty quickly becomes uncomfortable.
Yeah, yes, yeah, I'm reminded. I've mentioned this on the show before, But many years ago I got to see Bauhaus perform at Coachella and Peter Murphy was brought on stage inverted hanging upside down to perform Bella Legosi's Dead And at the time I didn't really know that this was special. I thought, well, maybe he does this all
the time. Much later on listening to the show, said, oh, yeah, this is the only time Peter Murphy ever did this, And I'm guessing this is maybe the reason why maybe being upside down for the entire performance of a rather long long song and the time before you're actually brought on stage probably not something you want to do more at once.
Yeah, it's not very good for you to. I mean, you know, short inversions I think are okay, but you don't want to be like that for a long time. It's certainly not comfortable. You know, blood tends to pool in the head because the body is made to be right side up and the circulatory system is specialized normally
for being right side up. And this even connects to you know, people who are in microgravity for an extended period of time experience discomfort due to the fact that outside of Earth's gravity, the heart is still trying to compensate for Earth's gravity with the way that it's pumping, with the way that it's pumping, you know, so they often end up with too much blood in the upper parts of their body up in the head and with
sinus congestion and that sort of thing. And so if you turn your body upside down, blood tends to pool in the upper parts of your body and your head that's not comfortable, and in the body cavity. The whole jar of spaghetti turns upside down. So the organs in your abdomen when you're invert will sit on top of your lungs, pressing down, making it harder to expand the lungs and breathe in. And actually, to be more precise,
they're not directly on the lungs. The abdominal organs would be pressing on the diaphragm, which is the muscle that contracts and expands down into the abdomen to expand the chest cavity when you breathe in. So when you inhale, you are contracting the diaphragm. It goes lower into the space of the abdomen. And if you're upside down, the diaphragm now has to lift the weight of the guts while it is contracting to inhale, so it makes breathing in harder. So The question is sloths are already on
a they're on a metabolic knife edge. You know, they are constantly fighting to have enough energy to survive because they know they have to live off of these leaves which are not super energy dense. So how does sloths manage to spend so much time hanging upside down without suffering made consequences? And the authors of this paper from twenty fourteen found the answer. Quote. Sloths are mammals renowned
for spending a large proportion of time hanging inverted. In this position, the weight of the abdominal contents is expected to act on the lungs and increase the energetic costs of inspiration, meaning breathing in quote continues. Here we showed that three fingered sloths Bradypus vireagatis, possess unique fibrinous adhesions that anchor the abdominal organs, particularly the liver and the
glandular stomach, to the lower ribs. The key locations of these adhesions, close to the diaphragm, prevent the weight of the abdominal contents from acting on the lungs when the sloth is inverted. So this is pretty cool. Inside the
abdomen of the sloth. There are these special pieces of connective tissue that, in rough terms, essentially duct taped the organ's life, the glandular, stomach, and the liver to the rib bones, so that when the sloth hangs upside down, the jar of spaghetti cannot just fully fall down to the lid. The digestive organs don't sit on the diaphragm and make it harder to breathe. Instead, they hang from the inside of the ribs, sort of like the sloth
itself hangs from the tree branch. The authors also found that the kidneys were lashed to the pelvic girdle in a similar fashion. They don't really move at all when
the sloth goes upside down. So yeah, so the liver, glandular, stomach, kidneys, all this heavy stuff in the abdomen has its own suspension so that it doesn't squash the lungs when the sloth goes head down to get these leaves, and by keeping the weight of the organs off the lungs, the authors estimate that these adhesions could reduce the metabolic energy expenditure of a sloth by between seven and thirteen percent when it is hanging upside down, because again it takes
more energy to expand the lungs and breathe when something is pressing down, and they say that the energy difference here is quite meaningful to an animal like a sloth, which again does not usually have a lot of extra energy to burn. Sloths are typically able to eat just about enough to survive and do not have much more
in terms of energy reserves. Another thing that the authors point out they were talking about this in that blog post, is that they sloths can store up to about a third of their body weight in gut contents before they have to go urinate and defecate, because remember, it might
be a week in between bathroom breaks. So that Sloth Conservation Foundation post points out that this means the waste products and the partially digested food in the gut make up a surprisingly huge percentage of the sloth's total body mass. Quote with their limited energy supply, it would be energetically very expensive, if not completely impossible, for a sloth to lift this extra weight with each breath were it not
for the adhesions. Oh wow, So yeah, think about all that, You know, all the partially digestive leaves and the poop and the pea all just weighing on you, maybe a third of your body mass pressing down on the lungs. But no, the sloth has adaptations to survive this. To get around it, they're taped up to the ribs. And this is also, they point out, not the only adaptation
that helps sloths in hanging upside down. They also make general reference to the fact that both two and three fingered sloths they're able to hang upside down for up to ninety percent of the day if necessary, and to facilitate this, they have special circulatory adaptations that probably keep blood pressure in the head under control, and they have a specialized esophagus that helps them swallow in this position, and things like that.
Oh wow, that's fascinating, The upside Down Lives of sloths total.
But oh, I know, you had a little bit more about bats, didn't you, in the In the upside down this becoming ranging into the uncanny.
Yeah, yeah, So basically I was I was looking at a few different texts, and one of the books I was looking at is The Secret Lives of Bats by Merlin Tuttle, who's a great bat expert. Ali Ward had a great interview with him on ologies at some point in the past that I recently listened to with with with my kiddo and one of their friends. But in the Secret Lives of Bats, Tuttle refers he cites the author Bill Shutt, author of Dark Banquet and also former
guest on Stuff to Blow your Mind and Merlin. Tuttle says the following quote, Bill Shutt found that bird feeding vampire bats stalk perched prey, taking one slow, upside down step at a time along the underside of the branch where a bird is sleeping. And so I just found that wonderfully creepy, because you know, it doesn't take much for a vampire bat to be a little creepy and cool. It's kind of what they do. But this just sounds like straight up Dracula behavior, right.
Yea upside down sneaking, Yeah.
And reminiscent of certain vampire films and just other uncanny films where you have some sort of be it a vampire or say, you know, a dark wizard crawling on the ceiling and then perhaps dropping down or reaching down to do something nefarious.
Right yeah.
Yeah.
So in my notes here at this point, I have some stuff on Dracula, and then I have some other folkloric entities, things that in various traditions that live upside down or in some way inverted, or are creatures of
the ceiling. But I'm looking at the clock now and realizing that we're pretty much out of time for this episode, so I would say join us next time, where we'll continue to explore the upside down in the topsy turvy, and we'll definitely look at some monsters and some spirits for sure, and who knows what other areas we'll get into considering the upside down, because there are just so many different ways to take it.
Totally, yes, all right.
In the meantime, certainly, we'd love to hear from anyone out there if you have any thoughts on anything we discussed here, or if you have recommendations for topics you'd like to hear us tackle in the future. We'll remind everyone that Stuff to Blow Your Mind is primarily a science and culture podcast, with core episodes on Tuesdays and Thursdays in the Stuff to Blow Your Mind podcast feed wherever you get your audio podcasts, and you can also find us on Netflix of course, if you would like
the audio video experience of the thing. Let's see. On Wednesdays we do a short form episode and on Fridays we set aside most serious concerns, so just talk about a weird film on Weird House Cinema.
Huge thanks to our excellent audio producer JJ Posway. If you would like to get in touch with us with feedback on this episode or any other, to suggest a topic for the future, or just to say hello, you can email us at contact app Stuff to Blow your Mind dot com.
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