Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Hey you welcome to Stuff to Blow your Mind. My name is Robert.
Lamb, and I'm Joe McCormick.
And as we continue our Halloween seasonal offerings, we have to ask ourselves a question, is there anything more suitably creepy than a vast collection of bones? I have a feeling that a number of you, like us, have found yourself, especially this month, this month, more than like any past Halloween, have found yourself wandering through your neighborhood and neighborhood yards
are just littered with plastic bones. Like every year, the skeleton decorations just get more and more intense, more gigantic. Some of these yards are just littered with plastic bones.
I can't remember if I've already mentioned it this year, but my daughter, who is very Halloween brained at this moment, is also especially skeleton brained, which she calls selkins selkin brain. So we have to go around the neighborhood to buy a request to see particular skeletons in particular yards. There are some that are better than others. There are scary selkins, there are cute selkans. There are beautiful selkins. There's a whole taxonomy, and I don't know exactly what the criteria are,
but she does. And it's clear that while a subset are considered scary, some are not scary at all. Some some are just beautiful things to admire. There. You know, it's like people are putting Christmas lights up.
Yeah, I mean, it is fascinating how the symbol of the skull, of the skeleton of bones, or the skull and bones. You know, at a very basic level, it always means death, but there are so many different tweaks on that, and so culturally pop culturally, skulls and bones can be very empowering. They can be very life affirming, They can be fun, they can be hilarious, even if there is like a very like basic message about mortality at the bottom of everything.
Have we ever talked before about the what I take to be implied humor in all of these anatomically incorrect skeletons that proliferate different kinds of animal, skeletons of animals that don't actually have internal skeletons, like you know, an octopus skeleton or a.
Skeleton the most ridiculous. But I've also seen some like there's one of an owl where the owl has its ears, so you need to tell by its profile that it's an owl skeleton.
There are dogs around our neighborhood that have cute, like fluffy dog ears in bone dog skeletons with the ears are phone ears, and I think that's because, Yeah, you wouldn't know it was a dog necessarily if it didn't have the ears.
Yeah, cat looks solid, though. We have a fake cat skeleton on our porch and I'm not sure it's one hundred percent anatomically correct, but I don't think it has any fake ears, but maybe it does. I'm going to check after a record and see if I've been duped.
The fact that we have to put these non bone things onto skeletons to make them recognizable as the animals we know in life gives you real perspective on paleo art and reconstructions of dinosaurs and stuff like. You know, you have to realize how much soft tissue there is, and that there is some guesswork involved in reconstructing the body of an extinct animal when all you've got is
an imprint or fossil of the hard parts. I mean, in some cases we actually do know, because you know, there are clues that you can get through fossil evidence of what the soft tissue parts may have been, but not in every case.
Yeah, later on in this episode, we'll be talking a creature, a prehistoric creature. And I was looking around to see if there was a nice bit of paleo art to throw into our outline, just for you and me to look at. And you know, I just wasn't. I wasn't taken by any out so I just included a picture of the skull. And it's like, the skull is the hard data in this case. Anyway, the skull, I think really illustrates a lot of what we'll be discussing regarding the creature.
But clearly skulls and bones are a big part of the imagery of modern horror. In fact, we're going to be talking about a weird house cinema movie this week that has a great bone body reveal. It's got a lady with a fleshy head and at one point they pull the cloak back and you see her her body is just bones, yes, or it's not just bones. I don't know. It's bones and some gungk.
But mostly bones.
Yes, bones, bones are revealed at least Yeah.
Yeah, there are so many great examples from especially from horror cinema and horror media that I think we can turn to where bones is especially big. Heaps of bones. Collections of bones are very very important, and they can read in different ways. So I thought we might run through just a few examples before we get into the
meat of our episode here. But you know, speaking of meat, I think one of the great ones is, of course, nineteen seventy four is the Texas chainsaw Massacre, where we have our characters, you know, slowly approaching the saw your home and as they begin to you know, creep every closer to the house in that ominous generator that's that's running, we begin to see like little bone trinkets hanging from limbs, and then when we get into the house itself, there's also like more things made out of bones.
Yeah, the saw your household is not wasteful. They don't like to throw things out, you know, they make use of what they got.
Yeah. Yeah. In other cases, we you know, we have plenty of examples of essentially a monster's layer where there are a lot of bones. One great example that I've always I've always liked back from my days when I think read the story for the first time in junior. High would be the nineteen seventy Stephen King short story Graveyard Shift, as well as the nineteen ninety film adaptation that I quite like. There's eventually you end up in
a vast subterranean chamber. It's just filled with human and animal bones.
Is that the one is about like a giant rat or bat.
Ultimately there is a giant rat or bat, and then just a lot of rats.
Yeah, yeah, you know, it's funny. These first two examples you mentioned highlight what I would say are the main two genres of bone collections in horror. One, exemplified by the Texas Chainsaw massacre, is the intentionally curated bone collection, often where artifacts have been fashioned out of bone, or where bones are placed in a particular arrangement. And then the other is the midden or the pile of bones, where bones are just accumulating haphazardly, And they both suggest horror,
but in very different ways. One is a kind of chaotic biological horror that just suggests a kind of like some animal is just like eating the flesh and stripping the bones and here's where the bones end up, whereas the former suggests a creepy fascination that suggests aberrant behavior and obsession.
Yeah, I think this is a good distinction to make. Yeah, there's certainly if there's a collection of bones somewhere and there's some sort of intelligence behind it, it's not necessarily an intelligence we want to interact with. You know, it falls under the heading of like trophy taking, and you know, we're not really going to go in that direction probably with these episodes. But I think there are plenty of
examples of that to point too in human history. But then the other example being like whoa, here's a place where there are a bunch of bones. A bunch of bones means a lot of death. Maybe a lot of death happened at once, maybe a lot of death has
taken place over time. But you know, obviously humans and are myth making and our supernatural thinking, those places can often be interpreted as places of bad vibes, places that might be haunted, cursed, or you know, in some manner given supernatural weight, they can also be rather holy places in their own right as well. But also the idea of a place where there are a lot of bones that could also spell the possibility of a very real
life danger. What if the thing that is producing all of these bones is still here some manner of predator or predators that could threaten us directly. I mean, that's getting into some of our basic hardwiring as an organism.
Yeah, that's exactly right. There are sort of ecological implications whenever you see a collection of bones that kind of
suggests what else may be about in the area. But then there's another thing, which is just the self reflective version of the reaction to seeing human bones in particular, which is I think of uh, the you know the quote from uh, you know, the story of Wilhelm Runken when he first you know, creates the X ray machine and he gets an X ray of his wife's hand and she she looks through on the plate and sees her bones printed on the on the image. Uh, and
she says, I have seen my own death. You know, you're not supposed to see your own bones unless and you don't unless there is some kind of catastrophic imagery. Yeah. I was gonna say injury, but yes, catastrophic imagery as well.
Yeah, yeah, yeah, I thought you were going to say if we do see our own bones. They better be dancing. It better be in carniform, you know. I should also mention the killer rabbit from a money python in The Holy Grail.
That's another great example.
Just look at the bones.
Look at the bone.
Now, we put together a whole list of additional horror movies that had some sort of bone collecting going on in them. We may come back to some of these as we get into specific examples, because we are, of course going to dip into the natural world here into the real world. And I thought a great place to start would be with a creature of prehistoric caves, a creature that accumulated bones in such caves and would have
been encountered by our ancestors. And I think this is particularly potent to think about because these would have This would be an example of a bone littered environment that our ancestors would have seen, would have thought about, would have processed, and also a creature that we would have had direct interaction with. I'm going to be talking about the cave hyena. The cave hyena consisted of two extinct species.
There's crocuta crocuta spellia and crocuta crocuta old Tema, and they would have ranged across Eurasia during the middle to late plus to seen, an age that saw the expansion of modern humans and the extinction of archaic humans, including the Neanderthals. There of course relatives of the modern African spotted hyena that is Crocuta crocuta, and there are also three other extant hyaena species, as well as other extinct species that they're related to, such as the giant short
faced hyena. Now, the modern spotted hyena alone is an impressive organism. I think everyone has some knowledge of this creature, hopefully more from documentaries than maybe going to zoos and so forth, as opposed to just the lion king.
But I thought you were going to say just having them as pets.
Or no, you know, please don't have them as pets. But you know, this is definitely an impressive and fascinating organism that we could we could easily do an an entire episode on, and they're more than capable of inspiring myth and legend on their own. I mean, they're large,
scavenging carnivores with a wide vocal range. They can make very perplexing sounds, and they're also noted and have long been noted for their propensity for a grave robbing, and sometimes they've been known to opportunistically prey on live humans. They are voracious bone eaters, and I'm to understand they can digest all organic components of bone, not just the marrow. So they are, you know, basically like the idea of like a graveyard ghoule is very much a humanoid take on a hyena.
But do I understand correctly with the spotted hyena, it not only gnaws bones to get the meat off, It actually eats the bones themselves. It crunches up the bone and digests the whole thing.
Yeah, that's that's how it goes down. And you can mentioned skulls earlier. You can look up the you know, certainly the skull of a modern spotted hyena, but also look up the skulls of any of these prehistoric hyenas and you'll just see how robust they are. And you can you can really take one look at this skull and realize, oh yeah, this is a bone muncher. This is a bone munching machine. Just look at those jobs.
This head is like the machine press that they crushed the terminator in at the end of the first movie.
Yes, yeah, exactly. So again, they're very fascinating creatures and they have They've inspired all sorts of different folk beliefs, legends, and mythologies. Ancient writers discuss them quite a bit also got a fair bit wrong about them, especially considering their
gender and sexuality. There are these various misnomers and in ancient writings about how they would they were they were like bisexual or hemaphroditic, or you know, various takes on this just obviously a classic case of of the observers not really knowing what they're observing and looking at with a particular organ. But then there are all these other crazy ideas as well, such as I'm just gonna read a little bit from our old friend plenty of the
elder here. Okay, a number of other remarkable facts about it the hyena are reported, but the most remarkable are that among the shepherd's homesteads, it simulates human speech and picks up the name of one of them so as to call him to come out of doors and tear him in pieces. What And also that it imitates a person being sick to attract the dogs so that it may attack them. That this animal alone, digs up graves in search of corpses, that a female is seldom caught,
that its eyes have a thousand variations and alterations of color. Moreover, that when its shadow falls on dogs, they are struck dumb, and that it has certain magic arts by which it causes every animal at which it gazes three times to stand rooted to the spot.
The last part is that a metaphor does he say, does he mean the animals literally grow roots?
I'm going to assume it's not going to that link. But but the idea I guess is that they they had they have the power to essentially hypnotize with their gaze.
Yeah, look three times in its freeze tag.
Yeah, I mean they're alarming animals.
Uh.
Sure.
And some of the footage and and images I've seen, and certainly again they have that extended vocal range. They create very strange sounds that we often compare to laughter. And you know, they're not alone in this. There are various other organisms that make sounds that remind us of human human laughter, human conversation, and it can be very uncanny.
You can almost sense the telephone game in this reporting. They do actually make strange sounds that could sound kind of human in ways, but here this this gets escalated to they say your name and call you outside.
Yeah.
Likewise, the whole bit about them being the only creatures to rob human graves, I mean, they're various creatures that if they can, if they can dig up a body, they will do so and get to it, you know. So it's not just in the hyaenas. And then also they are known to sometimes make opportunistic attacks against humans. They may in some cases become man eaters. But again they're not alone in them.
But to be clear, do we think that plenty here is talking about like the African spotted hyaena or is he talking about an extinct variety of Hyaena.
I believe he's talking about you know, sub Saharan African spotted hyaenas here. Okay, thus sort of the game of telephone in places here. Yeah, but yeah, suffice to say, it's a species that certainly invites mystery, and they occupy a number of roles in the traditional beliefs of people who have long lived beside them. You know, some fearsome, but also there are plenty of examples that are either ambivalent or even protective in their attitude regarding human beings,
so they're not just batties. So there's more than just the lion king in play when we consider myth making in legends with hyaenas. Sure, now I want to come back though, to, of course, cave hyenas, because modern hyaenas are broadly considered habitat generalists. You know, they may reside in they may reside in dens that they've dug out of the earth. They may reside in caves, they may lay around on rocky outcrops and various other locations. They're
generally quite flexible. Wherever they make their den, they may bring carcasses and bones back for further consumption and therefore litter them in that environment. And then we have the cave hyenas. And the name might easily summon the idea that, okay, well, these are hyenas that exclusively lived in caves, and therefore there's some sort of a cave specialist. But this too would be incorrect. So cave hyenas, despite their name, they could also make dens in various other places, and did,
but their use of cave dens is particularly pronounced. And these environments have served as time capsules, preserving the littered remains, the bones left over from their habitation there.
That makes sense. So because the caves protect what the hyaenas did inside there to some extent, that evidence is preserved, and so we have an idea of what cave hyenas were doing when they were in caves.
Yeah, and a lot of what we've learned about cave hyenas has come from these environments, and we've learned a lot about the animals that they preyed on from these environments. But the cave hyenas themselves, they would have been They were larger, heavier creatures compared to modern spotted hyaenas, and they were considered apex predators in their own right alongside
the likes of the cave lion. They were probably less skilled at running after prey or running away with meat and bone compared to modern day spotted hyaenas, but they would have been really good at dragging away much larger carcasses. So you know, they were essentially you can think of them as beefier and therefore better able to drag away big bodies, big pieces of meat. And this was a time when multiple large mammal species thrived and provided carcasses on a regular basis to sustain them.
So can you think of them as the tractor model rather than the sports car.
Yeah, yeah, I think that would be fair. Like there were a lot of big bodies that would occasionally drop to the ground, maybe with a little help, certainly with a little help either from cave hyenas or various other carnivore creatures. And then these guys would have been just really good at dragging the meat, dragging the bodies back to the caves where they could take their time breaking
down the bodies. And then also I'm to understand there would be a certain amount of a preservation in there as well, so sort of a cold storage environment, you know, I don't think that was the main point, but there would be some of that in play as well.
Yeah, low gear, torque, not speed.
Yeah, And so they'd occupy specific cave mouths on and off, and that's key for thousands of years, seemingly displaced by and displacing other occupiers, including Neanderthals at times, and also perhaps cohabitating certain caves with other creatures, either kind of at the same time or in phases, and in the process accumulating just great quantities of animal bones that would just build up over time. Nobody's dragging those carcasses or
those bones back out. They're just building up and providing this ultimately wealth of data for paleontologists to come in the distant future from their time.
So I assume you have examples of caves like this where their middens have been found.
Yeah, yeah, there was. In twenty twenty three, it was reported that the Siberian there's a cave near the Siberian city of Cacassia, and it was said to contain some four hundred kilograms or eight hundred and eighty two pounds of bones estimated, And this would have included the likes of mammoths, rhinos, bison, yaks, deer, gazelle, ancient brown bears, and then various smaller creatures like foxes, wolves, every you know, all the way down. These guys apparently weren't too proud
to drag you know, just about anything back to the layer. Now, there are various other cave hyena dens that are you know, important sites for paleontology, such as Zulithan Cave in Bavaria in Germany. This site is thought to have been a major cave bear den with cave hyenas, wolves and cave lions co occupying or scavenging over time.
Now, if we know that different types of carnivores or predators occupied these caves over different times, how are we able to identi when they were occupied by different types of predators or which predator it was that was responsible for a specific kill or for eating a carcass that's left in the cave.
Well, a part of it comes down to, you know, looking at the bones and seeing the wear and tear on them, because you know they would have been gnawing on them. We can essentially, you know, use byte data to understand this, like, Okay, what's been chewing on this bone? Well, it looks like it was cave hyenus, So that's part of it. And then there's just various other evidence in the way that the the different layers of sediment have
built up and where the bones are in caves. I was looking at a paper by Dietrix and Zach from two thousand and six and the Bulletin of Geosciences. This particular paper was looking at a at a cave in
the Bohemian Karst. This is in the Czech Republic and like they had a nice little illustration in this paper that I included here for you, Joe that kind of like lays out like these different sort of the different phases in occupation of a cave, with like cave bears occupying a place and then well a cave bears being larger organism kind of like you know, physically impacting the shape of things. We've talked about this on the show before.
How you have something like a like a large sloth, a giant sloth or or a bear, and when they're habitating in a cave, they kind of create these little indentions kind of like wallowing points, right, Yeah, and those you know, in the preserved environment of a cave, those those little indentions can remain over time. And what happens when hyenas come in with their bones, well they're liable to put those bones right in those indentions, fill those in. So we we have evidence like that that we can
look at. And in this paper they also discussed that, yeah, like you'd have cave bears and kive cave hyenas and they seemingly like trade back and forth over usage of the cave. So it's not just it's not necessarily a situation where you know, either organism is in the cave all the time, despite what you might come to think
watching an old caveman movie. But cave bears would use the caves for birthing and hibernation, and then hyenas would come in and use them periodically or seasonally for the drag in their their their kills, or their scavenge the meat and bones. So there's it seems like a fair amount of traffic in these caves when they're you know,
cohabitated or uh. And then certainly you throw in neanderthals and potential interactions with with our human ancestors where uh they would be competing for the same cave environments at times. Uh So, yeah, there's a lot of a lot of back and forth here.
So what happened to the cave hyena? They no longer exist?
Correct?
Yes, yeah they are. They are quite extinct, and it's it's notable that, in addition to changing climate, humans likely played a key role in the extinction of cave hyenas, likely out competing with it for prey and carcasses. Neanderthals, of course, had already competed with cave hyenas with with the with the cave Heyen is at least Cave Heyen is at least scavenging Neanderthal dead, if not outright preying on them from time to time as well. So that's
kind of interesting in and of itself. It's kind of like who we became the new masters of carcasses and bones to a certain extent, we didn't, you know, we didn't put it all in the caves. We started doing other things with the bodies, fully processing the bodies in our own human ways, uh, and in doing so, ultimately
changing the shape of the natural world around us. But it's it's interesting to contemplate potential human, early human interactions with these caves and the creatures that made their homes there,
such as the Cave Hyena. Because again, caves in and of themselves, as we've discussed in the show many times, have long been places of wonder and mystery, places of spiritual and cultural significance, places where one might find resources some resources anyway, certainly find shelter, but also encounter danger. And then caves were often seen as you know, gateways to some sort of underworld. So it's kind of fitting, or at least curious that our ancestors would have found
caves such as this just choked with bones. You know, one can't help, but wonder, like, did we think about them in such a way that like, here's a here is a cavern full of bones, some of which are bones like I have in my body. Is this, on some level some gateway to a realm of death?
Yeah, it's an interesting question. I do wonder for a prehistoric human, you know, Homo sapiens or Neanderthal, coming into a cave and finding bones in there, what is the most salient thing about that? What is your primary association? Does that make you think competition for this piece of shelter or does that make you think predator? Or does that make you just think death? Or does that make you think resources? You know, like, I wonder what is
the salience? Because obviously, you know, there are some just sort of objective facts about the reason we associate bones with death. But also I think we have to recognize that a lot of our associations between bones and you know, frightening horror ideas are culturally conditioned and contingent, and we might have different associations. I don't know if you're if you're like a butcher or something. You might have very
different thoughts about bones. You maybe mainly associate them with making a living or with you know, with food.
That's a great point because especially when we're talking about the humans here, the humans that are gonna outcompete the cave hyenas for scavenge carcasses and and of course it also kills of various mammals. You know, they're obviously people that are far more connected to the killing and butchery of animals than most of us are today. So yeah, they might have just been like, hey, these this place is great, This.
Is good hunting around here. Yeah.
Yeah, this is the kind of place I would love to have, and these cave hyenas have figured it out for themselves. Might have to steal some business from them. One more bit of cave hyena information I wanted to share for a little bit. There there was this argument that the accumulation of bones and caves like these were due not to prehistoric predators but to the Great Flood,
the Great Biblical flood. Okay, this was an idea that English geologist William Buckland in particular, who lived seventeen eighty four through eighteen fifty six, theorized early in his career concerning Kirkdale Cave in North Yorkshire, but to his credit, he later shifted his view based on his own findings. So he came around and said, actually, you know, these bones are this accumulation of bones, this is due to cave hyenas, though for a while he maintained, Okay, cave
hyenas are the reason. But see this soil deposited on top of the bones that's over from the Great flood. But then he later abandons this idea as well. But I like the idea that, like, here's somebody that is identifying evidence for a biblical event in the natural world and is not just illogically sticking to his guns, Like his opinion is changing based on the accumulation of actual, you know, objective evidence.
Yeah. Sure, respect to Buckland for updating. But though I haven't, I would like to go read about this because I'm like, why would the bones in the cave have anything to do with the flood? Why would that be different than bones anywhere else.
Yeah, I didn't go hard on this, but I mean maybe the idea is, well, the water had to drain somewhere and it took all those bodies with it, and this is just like the clogged bone drain of the earth.
Oh that's cool. Okay, cave, that's my guess.
That's my guess.
The drain at the bottom of the bathtub.
Yeah, yeah, okay, yeah, where all the bones go. There you go.
Okay. Well, given the distinction we talked about at the beginning of the episode, I think we could sort the cave hyena more into the middens category. This is a somewhat chaotically assembled pile of bones or animal remains that just happens to all end up in the same place because of the lifestyle or living habits of the animal
that brought them there. Then we had the other category, which was more like Texas Chainsaw massacre, where you have a curated collection of bones, animal remains, things that are put in a certain way for a certain reason due to someone's obsessive interest, and how that's frightening in a different way than the midden is than just the predator's midden. I wonder when we're done talking about the next example, which category you'd put it in, because I think it's
almost kind of a straddler. It could go either way. So I want to talk about an article published in the journal Science in April of this year, twenty twenty five by the researchers Daniel Rubinoff, Michael San Jose and Camielle Duran Weird called Hawaiian caterpillar patrols spiderwebs camouflaged in insect praise body parts. All three authors here are entomologists affiliated with the University of Hawaii at Manoa. So the authors begin this paper by talking about the interesting evolutionary
laboratory of the Hawaiian Islands. Because of Hawaii's geographic isolation from mainland populations for so long, it evolved lots of weird and interesting invertebrates, especially when it comes to Lepidoptera. Now a reminder, Lepidoptera is the insect order containing moths and butterflies. A lot of people already know this, but just to be clear, caterpillars are the same animals as the winged forms of moths butterflies, simply at different stages
of life. So caterpillars are the larval stage of the lepidopter in life cycle, in which the insect is this you know, fat little grub shape and it crawls around and it chomps the world. It's bulking up on food before finding a place to settle down and pupate. When it goes into the pupi phase, it undergoes metamorphosis, and then the winged forms that we think of as moths and butterflies kind of the main idea of what this insect is. The winged forms are the reproductively mature stage
after the metamorphosis of the pupa. This is the stage in which these insects mate and lay eggs. And the authors of this paper mention several fascinating caterpillar adaptations found in the Hawaiian islands, specifically in the larval phase of local lepidopterans. There are caterpillars in Hawaii that hunt snails. There are caterpillars that are amphibious or like live underwater. There are caterpillars that work as ambush predators. You know, they kind of lie in wait and they hide in
leaves and then they attack their prey. And this article is about another caterpillar from Hawaii that can be added to that list of beautiful monstrosities, the so called bone collector caterpillar of the moth genus Hyposmocoma. Which the author's rite is notable for quote, a bizarre housekeeping regimen not reported for any other insect, and an ecology not recorded
elsewhere in the order Lepidoptera. So what are these unique traits? Well, the top line is that this is the first documented caterpillar evolved to depend on spider webs as a habitat spider webs. And to be clear, we're not talking about like exclusively abandoned old spider webs or something. We're talking about active spider webs with a spider in them.
Oh wow.
Yeah. These caterpillars typically dwell in webs within like recesses, So you would find these webs in tree hollows or rock hollows or in the voids inside of fallen log We're talking about those kind of three dimensional, tangled looking webs you see in a little depression or indentation somewhere in the natural world. So that's where you're gonna find these caterpillars in webs like that. Now, that alone is
pretty weird. It's kind of like imagining a rabbit species that is evolved specifically to live in wolf dens.
Yeah, yeah, this seems like this seems like this would be the place most small creatures would not want to find themselves, leave it to the spiders and their prey.
Right, so the author is right quote. Although caterpillars and spiders are common in the same environments all over the world, only this single caterpillar lineage in Hawaii is known to have made the leap to spider cohabitation. In fact, I was looking this up in some other sources to see
if there was any contradiction on this. The only real counterexample I found was in a write up of this paper in The New York Times by Jack Tomisia, which quoted an entomologist at the University of Connecticut named David Wagner, who didn't really contradict this, but said he was aware of only one other moth species that had anything to do with spider webs. It didn't like live there entirely, but there was one moth species that was vegetarian and
would sometimes eat plant material caught in spider webs. But this is the only example that we know of anywhere of a caterpillar that lives in fully evolved to live in the habitat of a spider's web. Another thing that's crazy about this is that it's not just like caterpillar goes crawling around the world until it finds a spider web. From what I was reading, it seems like the moths here will actually try to lay their eggs in spider webs.
Oh wow, So you know the caterpillar hatches from the egg in the web, makes its home there, and just lives there. That's that is its environment, and there are some freaky specializations that make this arrangement work. Explaining both the why and the how of caterpillar cohabitation with a spider. The major part of the why is answered by another strange fact about the species. The bone collector caterpillar is a carnivore. Now, carnivorous caterpillars are, from an evolutionary perspective,
pretty rare. The authors note that of all existing insect orders, Lepidoptera is actually the most herbivorous overall, So moths and butterflies, in all of their life cycles are the most vegetarian of all branches of the class Insecta, but there are a few exceptions. About zero point one three percent of the roughly two hundred thousand known moth and butterfly species practice some form of predation in their caterpillar stage.
You know, I think most of us have to think back to probably our initial introduction to caterpillar anatomy and physiology and behavior, that being the hungry, hungry caterpillar. Yes, that basically tells you what everything you need to know. Right, Caterpillars have to eat. That's what they're here to do, to eat a lot so that they can become that
reproductive flying adult. Therefore, you know, it makes sense that most of them would be vegetarian, most of them would depend on plant matter in order to bulk up their own mass for metamorphosis. I guess you can imagine why there would be more of that as compared to some sort of a carnivorous body plan that is going to depend on just eating lots and lots of meat in order to make that metamorphosis.
Well, yeah, you can think about this evolutionary energy dilemma. Of course, animal based foods do tend to be richer in nutrients, they're going to be more high calorie, but they're also a lot harder to come by. And you know, the plant food is abundant and it's a lot easier to get to as long as you can get enough of it and you can process.
It right and deal with any kind of self defensive involved adaptations on the part of the plant. But there's you know, an arms race there between each side of the equation.
That's right. So, yeah, so only about zero point one three percent of the two hundred thousand known moth and butterfly species practice some form of carnivorous predation. This is one of those those rare caterpillars. Now a minute ago we already mentioned carnivorous caterpillars in Hawaii, the ones that hunt snails or maybe disguise themselves among leaves and launch an ambush attack. But those things, they sound like a
lot of work. What if you could get somebody else to do most of the trapping and killing for you, If you could just kinda crawl around and suck up the leftovers of a perfectly evolved predator.
It's not a bad plan. It's one that prehostoric cave hyenas and prehostaric humans in some situations would have could definitely get behind.
And yeah, so here we come to the why of the bone collector caterpillar. These carnivorous insects live in spider webs because spider webs are great places to, in the words of Mick Jagger, get the meat. That's where they get the meat. The author's right quote. Bone collector caterpillars crawl through the jumble of web and detritus and opportunistically eat any weakened or recently deceased insects they come across, eg. Cased spider prey, so stuff the spider might have left
over after eating or might be saving for later. That's caterpillars now, yum yum. And they will even chew through the silk of the web to get to the meal so they can they can remodel the web environment to suit their needs if they need to get to food by going through it.
Ah devious.
I sort of mentioned this already, but the bone collector caterpillars. One thing about them is you're typically not going to find them in the plane shaped webs or flat sheet webs that you would see suspended out in the air between branches, the kinds of things that you're going to expect a butterfly in its adult stage to fly into. You're instead going to find them in these these tangled, three dimensional webs that you see spun in enclosed spaces
like recesses in wood. Because these caterpillars specialize in the three dimensional webs, they can generally reach prey in any part of the web, and it seems that they are quite adaptable scavengers and predators. In other words, they can they can and will eat any insect that is immobilized, weak, or slow moving. In fact, they will even cannibalize each other, which is why you typically only find one bone collector caterpillar per spider web. If there were two, there would
soon be only one. The larger would eat the smaller.
Ah, there can be only one.
Gotcha.
Now, where does the name come from? Why are they bone collectors? It's sort of a cute name, because, of course we're not talking about bones here in the mammalian sense, In the vertebrate sense, we're going to be talking about almost exclusively prey with exoskeletons arthropods. But this is the other fascinating thing about them. These caterpillars cover their bodies in portable cases made of silk, and to the outside of that silk case that they make, they attach chopped
up insect body parts. They don't seem to be very picky about what kinds of dead bodies are allowed to contribute. The authors report a single catterp having remains from as many as six different insect families stuck to the outside of it at once. In fact, Rob, I've got a photo from the article for you to look at here if you can see it in the outline. On the left, we have an adult female specimen of the bone collector caterpillar moth. This is what it looks like after metamorphosis.
The adult moth is kind of a furry brown and white spotted appearance. It looks almost looks almost a Malian in a way. I see it kind of you know, looks like you would want to stroke the hide and dignified.
And this is a dignified looking moth. Yes, the no hint of any kind of grotesque, shady past.
On the right, we have the decorated silk case of a single caterpillar in the larval stage, which is absolutely spangled with invertebrate death. It has an ant head, fly wings, fly legs, a weavil head, a bark beetle abdomen, and then all over in between all that what look like jointed orange tubes, like little orange straws. These, in fact, are not prey animal pieces. These are parts of the
host spider's exoskeleton leftover after molting. So it is the caterpillar has a bone armor of spider integument and dead hollow pieces of insect exoskeletons.
Oh my goodness, it looks just absolutely apocalyptic.
Like it shambling junkyard of insect death.
Yeah, like, I mean, one instant you know, pop culture fantasy comparison is, of course, the character Rattleshirt from Game of Thrones. Yeah, the characters wearing armor that's made from like human bones and all Lord of Bones. Yeah, but that looks far more dignified than what we have here. What we see with the bone collectorc caterpillar is much more Texas chainsaw massacre. It is just pure chaos.
Now. The fact that the caterpillar's silk case is covered in an insect slaughterhouse might make it seem like the stuff just kind of clings on their at random, right, Like maybe it just gets stuck there as it crawls around in the web. But no, there is diversity and variety, but it is not just randomly assembled or chaotic. The authors describe how you can observe the caterpillars carefully shopping for just the right parts and shaping them, you know,
to fit just right. They will pick up an ant head or a beetle leg, whatever the part might be, and then they will measure it for size before adhering it to their silk case. So they will rotate it around, rotate the body part, feel it with their mandibles, and if it's too big, the caterpillar will often modify it by chewing it down until it's just the right size.
Oh yeah, this gets even more horror show by the moment.
Here's an interesting thing. The authors of this paper found that if you put one of these caterpillars in captivity and you deny it access to insect body parts, but supply it with little, similarly shaped things that are other than insect body parts, it will not use them. So it is not like a hermit crab that will take up residence in a vienna sausage. Can the bone collector says, chopped up, chewed down dead bodies or nothing, that's all
that's all I want. And this is this is interesting because I think this implies possibly the fact that they're corpses and the remnants of spider molting that may be crucial to the caterpillar's survival somehow. The author is right quote given the context, it is possible that the array of partially consumed body parts and shed spider skins covering
the case forms effective camouflage from a spider landlord. The caterpillars have never been found predated by spiders or wrapped in spider silk, so these authors here have studied these things for years. By the way, this is a research years in the making, and there is not a single documented instance of these caterpillars slipping up and becoming spider food.
So is it possible that the bone cloak hides them somehow, makes them invisible or makes them uninteresting to this power predator a few centimeters away.
Like any given zombie film or comic book where someone covers themselves in zombie gore in order to pass through the horde unnoticed.
It could be. Yeah, we don't exactly know now. The authors also note the adaptability of the bone collectors survival strategy. I thought this was really interesting. While the bone collector caterpillar is native to Hawaii, of the four different species of spider in whose webs they have been found none of those spiders is native to Hawaii, and so the authors note that like of course, non native species dominate many of Hawaii's ecosystems. This is something we've talked about
on the show before. So if this this moth had been too dependent on just a single species of native spider as its web host, it might not have survived recent exchanges with the mainland. But it's adaptable to different types of spider webs, so it has. And yet human encounters with these caterpillars are pretty rare. The author's right quote.
These caterpillars are only rarely encountered on. Over twenty two years of fieldwork and over one hundred and fifty field surveys in the area where they occur have yielded only sixty two individuals, and most apparently suitable spiderwebs do not host them.
Oh wow, So they would seem to be a rarity even among the sort of webs that they could call.
Yeah, assuming we know where to look. But they do seem to be, as far as we can tell, limited to this small range, and as best we can tell, they're contained entirely within this like fifteen square kilometer forested area of a mountain range on the island of Oahu, though they used to have a larger range, we think.
Through filo genomic analysis, the authors found that the species is at least six million years old, several million years older than the island of Oahu itself, and probably at least a million years older than any of the major Hawaiian islands that remain today, which implies that this lineage probably first appeared on Hawaiian islands that no longer exist or you know, have eroded into the sea, and then it migrated to inhabit new islands that came up, including
islands that do still today exist in the Hawaiian island chain, but no longer have these caterpillars on them.
Oh wow, now that new they have almost kind of like elder god status, right, and some sort of elder creature like we hail from islands that no longer exist.
From the lens that sank we came And so the paper also does get into conservation concerns. Of course, Hawaii is one of the extinction capitals of the world, with introduced species and other factors threatening native life. They write, quote, the current range of the bone collector lineage is now limited to a single species holding on in a fragment of isolated forest that is increasingly beset with invasive species, exemplifying the vulnerability of many endemic Hawaiian insects and the
ecosystems on which they depend. So, of course, you know that highlights conservation concerns that are true of all different kinds of Hawaiian wildlife, and especially wildlife island wildlife all over the world.
Yeah. Yeah, thinking about how how fragile something like this is and how it could have easily passed away without us having a chance to even understand it and chronicle it. You know what other strange oddities of the natural world have just completely passed away without evidence. You know, we're lucky to have this.
But it is really amazing to think about the spider's web as a life niche for something other than the spider itself. There are clear advantages. It provides food for a carnivore. You can swoop in there and eat, eat after the spider is done eating, or eat what the spider has saved for later. It provides presumably protection against other predators. You know, there are a lot of things that might threaten you otherwise, but they're not going to
go messing around in a spider web. But there's a spider, so it seems pretty clear that there is some part of the silk case adaptation, you sticking all of the dead insect body parts to the silk case that protects the caterpillar against the host spider. But why does that work? How does the dead body parts suit protect the caterpillar.
In one article I read, it cited the idea that maybe it makes the caterpillar look like trash to the spider, like, you know, it looks like this is the stuff I've already gotten rid of and no longer have any use for us. It's just not interesting to me. But I do wonder kind of how that actually works in the spider's brain. What does that look like to the spider?
What's going on there? And I wonder how it would not be excited by, you know, the things that draw it to prey that comes into its web in any other case, like movement cues, vibrations in the web, or smell cues or something like that. I don't know, but it's super interesting that this animal can live in what would seemingly be like the most hostile of possible spaces.
I'm imagining a terminator heads up display situation where it's like looking at it and it just says trash, you know, classification trash. But yeah, I mean it's so and it's also just so interesting to try to imagine like the presumably you know, gruesome and and doom ridden evolutionary journey to this point. Yeah, where you know this is this is a niche that had to be occupied over time, and you can imagine a lot of mistakes were made along the way.
Oh well, that brings up another interesting sort of phylogenetic connection, which is that within this moth genus Hyposmocoma that you find throughout Hawaii, there are many other different kinds of unique cases. So the it's not just the bone collector. There are relatives of this moth where the caterpillar phase of the life cycle has the has these weird cases it makes that are i think, in most cases thought to help it blend in with the environment around it.
This is the only one that puts dead insect body parts on itself and hides some spider's web. But there are these others that make these cases that are said to look like a crab. There's one that's called like the candy wrapper caterpillar. It looks kind of like a candy wrapper. There's one that looks like a cigar. There's one that looks like I think they say it looks like a burrito. So you get all these different shapes. I think generally they're thought to just be types of
camouflage that help hide this from potential predators. But the bone collector really stands out like it looks quite different and much more striking than the other ones, which I think are mostly trying to appear drab and blend in with I don't know, an environment of leaves or sticks or something. But anyway, coming back to the question, where does the bone collector caterpillar fall on the you know,
Cave Hyena versus Texas chainsaw massacre at scale? Like, you know, this seems to be much more intentional than the the midden of bones that has formed chaotically just through you know, you're eating nearby and that's where the bones get deposited.
Yeah, it's really kind of taking advantage of a mitten. It's taking advantage of a a of an accumulation of body parts or bones if you rather, and then using it intentionally. It's like if you lived in the Texas Chainsaw massacre house, but you were not a member of the saw your clan, and you just covered yourself up with bones just to blend in with all the bone bone decorated furniture and so forth.
And you get to eat leather faces lunch when he's not looking because you covered left.
Over barbecue left under slaw. You know, I was sure I had some food.
On my plate. Well, off to the bone collectors. I like your your style. Obviously the bone suit is cool, but also it's just like bold behavior. You know, this is a this is a boldness admired. I admire you from afar.
I mean, it's it's a frequent story and evolution where you know, not not to personify evolution too much, but it is fun from time to time, and it's almost like gain evolutions to Hey, you know, there's a good living to be made living in a spider web if you're not a spider in the same way that evolution might whisper you know, Uh, there's a lot of riches in a bee hive. You could get in there and not alert the bees to your presence or make them
think that you belong there. Well, there's a lot of honey in there, there's a lot of resources, and these are all you know, these are all dangerous missions, dangerous hests. But evolution is generally up for the job.
That's true. This is not the only infiltrator in nature. Yeah, but maybe the most morbid looking one. Yeah, okay, Well should we call part one there?
We should call part one, yes, but we will be back. Let's see today's Thursday. We will be back on Tuesday with a second part in which we'll look at some other creatures that make use of the bones, be they literal bones or some other parts of dead organisms. I will have a few more examples to discuss in part two. In the meantime, we'd love to hear from everyone out there, you know about any of the organisms we talked about here, or other examples from horror cinema, horror comics and so forth.
There's some other great examples, you know. Actually, I will go ahead and mention one real quick that came up in my research. This is not a movie that I have seen, but there is a two thousand and three British Canadian horror film titled The Bone Snatcher which apparently does feature some sort of an insectoid creature that wears the bones of its victims. So it's like covered in bones or somehow partially armored in bones. I'm not sure,
but it is. It's kind of interesting. This would have the two thousand and three and it does kind of match up with what we were discussing here with the bone collectorc caterpillar. I couldn't really find a good screen cap of the monster though, so I don't really have a great sense of it.
Well, I don't want to insult a movie without having seen it, but it does have a real two thousand and three kind of look. Yeah tagline it will scare you out of your skull.
Maybe so, maybe so?
All right, next time.
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