Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Hey, welcome to Stuff to Blow Your Mind. My name is Robert Lamb.
And I am Joe McCormick, and we're back with part two in our twenty twenty six crab Bag series. By somewhat popular demand, we are we're doing a sort of roundup or maybe a pinch up of crab related subject matter. This was in part inspired by a listener male that we talked about in our most recent listener Mail episode. And we're always down to talk about some crab stuff. No real organizing principle here, it's just yah assortment of
crab topics, a crab buffet. So in the last episode we talked about the legend of a miraculous crab associated with a Catholic figure named Saint Francis Xavier, and how that legend sort of connects to a real decapod species in the Western Pacific and Indian oceans. We might revisit that topic today. I'll explain more about that later. And then also at the end of the last episode, we talked about an idea known as crab theory or maybe under various names, but that's one way to refer to it.
It's a metaphor for chaotic, anti cooperative human behaviors in certain situations, based on the supposed behavior of crabs in a bucket. And we briefly got into the question of to what extent crabs ever could be said to be socially cooperative, And we're back today to talk about more.
That's right. So for my own part for this episode, I kind of poked around and I wanted to find something to talk about that's tied directly to some crab species. But then also I have some stuff that we'll get into later that involves some crab folklore and indeed like a crab demon or crab spece from a particular tradition. But first, yeah, let's talk about frog crabs. So, listeners, do you like to dance like a crab? Have you ever danced like a crap? I hope that you have.
I hope that you can. I hope that you're doing
it right now. Perhaps scuttling side to side on wide legs, arms out to either side with fingers or hands you can sort of choose forming the clacking makeshift pinchers, or perhaps you prefer to do a kind of crab walk that it's in the sense that you might encounter this in an exercise class or an exercise routine where you move around on all fours and kind of a reverse tabletop pose, so belly up, all four limbs on the ground walking side to side do I think sometimes people
do the crab walk back and forth as well.
All of the above very popular with my three year old. In fact, for a while, part of our standard bedtime routine was that I had to do a crab dance, so like she would demand a crab data performance before she would go to bed, and it was really funny for a while, and then I guess the gag wore out.
Yeah. I have observed that kids can really do the all fours reverse tabletop crab walk like nobody's business. They can really get down there and do it. There also seems to be a standing crab walk exercise that entails side to side movement, but with like banded thighs. I don't know if you've encountered this one. You can find videos and image of this online.
This is like a like an exercise or it's.
A yeah, it looks like it's popping up in exercise videos and exercise routine where there's some sort of a band that is placed around a human's thighs and then they move side.
To side the thigh master crab method.
Yeah, yeah, it seems to be the case.
Okay.
I always think of when I think of crabs moving side to side, I think of Zoidberg from Futurama. I also think of a particular Japanese rest slur by the name of Grand Naniwa, who he's passed now, but for a while he was like a comedy wrestler with a crab like mask, and one of his signature moves was to move side to side whilst making little pinchers with his fingers and then doing an elbow drop off the ropes.
I actually looked this up. So he's he's not only walking side by side and pin doing this, but he's doing it on the rope between the what do you call it the turnstile the turn turnbules.
Yeah.
Yeah, So he's going back and forth on the rope, I guess, preparing to jump and do the elbow drop, right.
Yeah, powering up, summoning the power of the crab. I don't know how many winds he picked up with this particular maneuver, but it was it was funny to watch.
I found it quite admirable.
Yeah, and great mass for sure. So you know, generally, but not always, when we engage in human crab antics, Yeah, we're gonna move side to side lateral movement, because that's how a great many crabs move around on land. If you're out walking on the beach or on the pier and you're looking at sand crabs or rock crabs and you're watching them, you know, secretly move about, you're probably watching this rapid side stepping action. This is what they're
known for. And indeed, true crab anatomy is just optimized in general for side stepping. They can do rapid changes in direction. If you've ever tried to chase a crab on the beach, you've found this out. They can easily stop going one way and start going the other way. And I don't know, at least for humans, I've found that it tends to send a message as well, like the crab is saying I'm looking right at you, my claws are out, but I'm moving away from you latterly.
At least, you know, I think a lot of gamers might appreciate the metaphor of I don't know a strayfing, but whatever it is, it's some kind of like a fighting game or first person shooter. You're moving sideways really fast to try to confuse your enemy, but you always want to be facing them, and I guess have the same idea.
Yeah, yeah, I'm suddenly I didn't have this in my notes, but I'm reminded now. I think I saw this movie, or at least I remember seeing trailers for it. But there was a two thousand and six Japanese monster movie slash sports comedy titled Crab Goalkeeper, in which like a football or soccer goalkeeper is like a giant or at least man sized crab monster. Yes, because you know that, of course, isn't the optimal situation for somebody with phenomenal lateral movement.
That's brilliant. I love it now.
In general, it's worth knowing that that side to side movements of crabs, this is something that evolves as crabs leave behind their more lobster like evolutionary origins, and there are a number of little explainer articles online about this. Matt Slater has one for BBC's Discovered Wildlife in twenty twenty four. You know, look that up if you want
some more information about it. But basically, like a lobster like form is only going to be able to more expressly move forward, its tail is going to get in the way. And so as it as these organisms took on their full crab like form, most of them end up having this lateral movement ability.
Oh okay, yeah, so it's a change that occurs from the more lobster morph to the crab morph.
Right, yeah, and and it gets it gets a little more complicated than that. We'll come back to some examples why. But like one extreme example would be the Japanese spider crab. I think everyone's seen one of these, you've releast seen pictures, but they also pop up in aquariums. They really almost don't look real.
Big long, spindly legs compared to the body.
Yeah, the largest crabs, and they move quite slow in you know, deep environments, and they can move side to side certainly, and I believe side to side movement is maybe a little bit faster. But they all also move front to back. So you know, car is subject to change with evolution if new matters come to light. Plus, as we've touched on before. Not all crabs are true crabs. The hermit crab, of course, is a great example. We've
talked about this before. If you watch them on the beach, you know they're going to do a lot of forward momentum movements on the beach. You know, they have the ability to move around in other directions as well, but they're full speed ahead for the most part.
Yeah. And when it comes to movement, the hermit crabs have a whole other thing to contact with. You know, they are moving hardware.
Yeah. So most true crabs are going to generally be lateral movers with bodies that are wider than they are long. But we do find some exceptions out there, and one of the main exceptions is that of the frog crabs, also known as the spanner crabs because their claws look a bit like wrenches or spanners.
I can see it. Yes, So these are crabs.
In the Rannini day family, with Ranina Ranina being the best example of this crab variety. This is not to be confused with the crab eating frog. This is a frog crab, so named because I guess they kind of look like frogs when if you find an image of one just like a top down image. I don't know, it's harder to get that sense of a frog. Basically, these guys are squatter, They're not wide, They're narrower and
longer while still being you know, bulky. They have paddle like limbs, and as Jeff Heck pointed out in a twenty fifteen article for New Scientists titled the Tasty Crab that looks like an Ugly frog, they sometimes assume frog like poses. And I think this is where the frogness
of the thing comes into play. If you look up an image of one of some of these creatures, look for the images that are not like top down like specimen shots, and more like the ones setting around on a rock, and you can see, all right, they have kind of they can take on this kind of squat almost mammalion pose.
I absolutely see it now. So you've got in the outline here one image of a side on image of one of these things sitting up against a rock, and it looks very much like a frog. It's kind of
squatting on its back legs. It's got the front legs out like you might see a front you know, frog's front legs, the long ones pushing it up in the sitting posture, and then even on the underside of its body there is a paler section than the rest of its body, kind of like you often see the paler underside of a frog's throat.
Yeah yeah, yeah, so they're they're pretty neat looking. I should note that their spanner like claws are not as powerful as that name might imply. So. The crab's limbs in general are evolved for superior burling, which they do backwards, and the front pinchers are mainly for gripping the sandy bottom. They also use them for a grasping soft prey. Generally they're scavengers, come out to scavenge things that have fallen down, but they will also sometimes grab, you know, small marine
organisms that they can. They're they're good swimmers. But when they're walking about, when they're walking on the on the seafloor or on the sand uh I have read that they cannot walk sideways. I'm always hesitant to be too absolute in those kind of rulings because it's kind of like saying dogs can't look up right. But generally speaking, their body is positioned in such a way that they are they are front back movers, as opposed to lateral movers,
and we see that in just their basic morphology. Now we mentioned already the lobster origins of crabs, and apparently for a long time naturalist thought that frog crabs were therefore a more primitive form of the crab, kind of a missing link between lobster and crab. But now we know that this is not the case. So these frog crabs evolved and estimated one hundred and twenty five million years ago, with their bodies and movements adapting for this
burrowing behavior. They burrow in the ocean floor sediment as a place of refuge, and again they emerge at night to scavenge and sometimes use that hiding place as kind of a you know, a trap from which to snatch small marine animals and eat them.
Okay, but it's not like all modern crabs were descended from a frog crab like ancestor.
No, no, no, no, It's more like they went back. They're like, actually, the something more lobster would be in
keeping with what we want to do with our lives. Interestingly, while frog crabs are now limited to certain tropical and subtropical environments, they were once quite plentiful across Earth's oceans, especially during times of low marine oxygen levels, and the general theory here seems to be that conditions these conditions might have been better for them because they might have been predisposed for low oxygen environments because of adaptations they
had for living in burrows and spending a lot of time beneath the sediment.
This is interesting because it's I think the second example we've looked at in just a few days of lineages of animals that are thought to have survived harsh conditions or mass extinction events because they were burrowing and they had burrowing behaviors, like we were recently talking about, Oh, in the Pokemon episode, we were talking about the desygnodont tetrapods, you know, these thrapsid tetrapods that were affected by the
Permian Triassic extinction event. Of course, like everything was, but some of the lineages of the Desygnodonts survived this extinction event, and that is thought to be in part because they were burrowing animals and that gave them a leg up in this really really harsh environment after the volcanic conditions that caused this extinction. And so this would be another example of an animal that's thought to be a survivor of harsh conditions because it burrows.
Yeah, yeah, absolutely, but in a marine situation instead. So humans apparently don't see these crabs as often as other crabs. I mean, there are a lot of crabs that don't really want to be seen, especially by birds and other creatures.
Which crabs do want to be seen.
Yeah, I don't think any of them. They would prefer you not look at them. They have things, and I don't know, I guess there's certain maybe a coconut crab is less a very large one, but even then, you know, they don't want no organism wants to be looked at by things that might want to eat them.
I guess, as always the question is seen by who. Yeah, you got some real show off crabs out there, like the fiddler crabs with the big claw, like, yeah, they're shown off to somebody, maybe not to us.
Right, So yeah, given their habitat, they're feeding habits, they may not be seen as much, but they are considered a delicacy in parts of the world. I understand they're particularly popular in Australia and in the Philippines. So listeners out there write in if you have tasting notes about the frog crab or the spanner crab, how is it different? How does a cook up? I don't know. I don't think I've ever had one.
This reminds me that the crucifix crab we talked about last time, Caribtis feriata, is also said to be a quite delicious crab. So if you've eaten crucifix crab, I want to hear about it now.
Of note the frog crabs here, they're not closely related to the decabot crustacean mole crabs. Mole crabs are in the superfamily Hippoa day and they have a similar body layout. But it's apparently a case of parallel evolution, with each crab evolving for burrowing. So if you're gonna if you're a crab and you want to backtrack a little bit in your body form you want to get into the burrowing lifestyle, there's a certain direction your body plan is
going to go in. Another burrowing crab that I ran across is the masked crab or helmet crab of the North Atlantic and North Sea. Let's see this one's scientific name is and I may butcher this Carrestius castaveolanis, but it's so called helmet crab or mass crab because the markings on its back allegedly resemble a human face. Included an image here for you, Joe, you can you can rule on this.
I see human face. I also kind of see a feline face, kind of a big cat.
Yeah.
Yeah, so it looks kind of like whiskers maybe along the cheek it does.
Yeah, with the legs certainly add to this effect.
Yeah, but this is another faceback crab, and we've talked about this on the show before.
That's right. This brings us back to the Japanese Hikagani crabs with the shell pattern that famously resembles a human face or a samuraiz face mask, tied to folklore traditions about the crabs being reincarnations of these warriors who were defeated and drowned beneath the waves of the Nakel Battle of Dan No Lura. We talked about this in a
previous episode of Stuff to Blow Your Mind. I believe this is one where we also talked about how it was discussed back in the day on Carl Sagan's Cosmos TV series.
That's right. Actually, I thought this would be a good time to revisit that because when we last talked about these, we talked about the idea popularized by Carl Sagan in so this was in the original Cosmos TV series. I think this was the year nineteen eighty. Carl Sagan was not the originator of this idea, but it was made very famous on that show. And the idea was that the Hikagani carapace could have been made more face like
over time by the process of artificial selection. And I'm going to critique this idea in a minute, but the story goes like this. You've got crab fishures going out over the centuries catching these crabs, and they would keep the crabs that looked less like faces, but throw back the crabs that looked more like faces for fear of crossing a taboo or eating a human spirit. So it looks to human. Oh, I got to get rid of it.
And the idea was by doing that, you naturally drive this species to look more and more like human faces over time. It's an interesting idea and in principle could be true. Artificial selection like this can and sometimes does happen. But I think especially in the years since we first talked about the Samurai crabs on the show. I've read some additional skeptical takes that make it seem pretty unlikely to me that artificial selection had a role in shaping
the carapace of this crab. We may have actually talked about some of the Yeah, we talked about some of these reasons in the episode, but it now seems to me more like a consensus view that there's probably not any artificial selection going on here. One of the main reasons is that the Hikagani are not a species significantly fished as food anyway, so there is not significant harvesting of these crabs in any case, you know, whether they
look like faces or not. And then the other thing is that the patterns on the carapace that we interpret as the raised parts of a face, like the nose and the cheeks and the depressions of the eyes and all that these patterns are not cosmetic in the biological sense. They're not just random decorations that can be easily moved around to look like whatever. In a nineteen ninety three article for Terra magazine, the invertebrate zoologist Joel Martin explained
this by saying, quote. The grooves and ridges on the backs of the crabs have specific purposes and are not merely decorative. The grooves are external indications of supportive ridges called apidemes inside the crab's carapace that service sites for muscle attachment. Elevated areas between these grooves allow for an increase in internal space so that the various parts of a crab's viscera, gastric, hepatic, cardiac, brachial, et cetera are
reflected externally. So I think the implication of that is that evolution would not be just free to play around with rearrangements of these features to favor a non fished face morph because the raised and lowered parts are functional, so moving them around would not be impossible. I mean, you know, the functional parts of an animal can move through evolution as well, but it would come at a high cost of fitness. The pressure to move them around
would probably have to be very strong. So I was thinking about this, and I would wager a guess that the resemblance of certain crab shells, like the one you were just talking about. What was that called again, the mast crab or the helmet crab from the North Atlantic and the Samurai crab, that these resemblances to human faces are probably going to just be a fairly common coincidence because faces and crab bodies have the same primary organizing principle,
which is bilateral symmetry. So when an animal body region is left right symmetrical, you're gonna end up with some structures in mirrored pairs on either side, like eyes and cheeks, or like lungs and gills, and then you're also going to have some structures masked around or near the middle near the meridian, like nose, mouth, heart, gut, to that
sort of thing. So it's I think just not that surprising that some surfaces reflecting the arrangement of underlying organs and the muscles that support them will look like faces, because both faces and internal organs in a crab are left right symmetrical, so it's a left right symmetrical Rorschach test.
You're just gonna get some faces. But on the other hand, I want to make clear again that while I think this is probably not a case of artificial selection on a wild animal population, that absolutely does happen sometimes, so it's not like the principle is invalidated. You can have artificial selection on wild populations by aggressive hunting of certain
types of animals. You know, if there is an animal that has a certain body part that is prized by hunters over time, you know, if that's aggressively harvested and hunted, you will see that animal population often shift to basically not have that trade anymore. So this can happen, and we can see an extreme form of artificial selection in domesticated animals and in plants and other organisms of course.
I mean, you know, domestic dogs or bread for extreme with extreme selective pressures on desired traits.
Right, right, So the mechanism absolutely exists, but in this particular case, it's probably not a factor. Right, And as always we have to stress that as humans, we would we look for these faces. We see faces if they're just barely there. So it doesn't take much for us to look at a crab or any other organism and say, oh, my goodness, that is clearly a human face. That is clearly a human skull, and in factor our own stories into why it is there.
Yeah, let me paradolia please.
Yeah, all right. In the last episode, you know, we talked a little bit about how there may be weren't as many crabs in folklore mythology as we would like, but we did reference that. You know, there are some great examples, and I was looking around for something new on this front and I found one. I didn't find as many sources, and I didn't find much in the
way of recent sources. So I do want a flag that I'm working from sources here that are from like the forties and the twenties in a couple of cases, so they're always caveats with that sort of information. But what i'd sounded really fascinating. So it is another example of a supernatural crab, and it is called the Nakalla, and it is a familiar of a male sorcerer that takes the form of a kind of demon crab in
the traditions of Zambia. According to Witchcraft, Divination and Magic among the Balival Tribes by cmn Wit nineteen forty eight, these are one of several types of familiars said to be either inherited in the case of female practitioners of dark magic, or quote prepared by matt recipes in the case of male practitioners. And this seems to be specific
to the Lundon people. This is a Boundtu ethnic group. So, according to this text, some of these familiars, because there seem to be a vast array of familiars that may be manifested by these individuals. According to these folk tale traditions as related in these texts, some of them, especially a snake familiar form, often take on the face of their master, and their life force is tied to their master,
so when the master dies, they die as well. And it seems possible from the context here that the Nakala crab demon or crab spirit also possesses the face of its master. White gives us this description in the text quote. The animal spirit known as Nakala also lives in rivers and is supposed to resemble a large crab with big claws and nose like projections. Describes how it is destroyed by the diviner calling it from its hiding place by
whistling on a horn. This horn contains a preparation made from the body of other nicala which he has destroyed. The nicala is shot when it makes its appearance, and the diviner removes certain parts of it to use for future medicine required for calling forth others of its kind.
Oh Okay.
Now the Miland here he is referring to is Frank H. Miland, who wrote about this spirit crab in an older text nineteen twenty three is which bound Africa, and he has these are some other details from that text. So Milan shares that the Nicala is said to be about four feet long and kills people by eating their shadow.
Oh. Interesting.
Yeah. He also adds, I'm going to read a section here that contains some more details about this quote. It is about four feet from head to head, for it has a head at either end, oh, and is nearly as broad as it is long. Each head resembles the head of a hippo, having the same lumps on it by the eyes. When it is eating a person's shadow, it eats with both heads simultaneously.
Wow.
Yeah. There are more details about the killing of the Nkala, like what sort of horn is used and so forth, like a more complete recipe for how the Nakala slayer carries out his business, and I want to mention that elsewhere. Seemingly unrelated, He also mentions a Lunda tradition by which one's life energy could be magically stored inside a shell of some sort. Sometimes a crab shell so that one's
enemies cannot destroy it with witchcraft, which is interesting. So it's like I will take on the crabs protection for my own life force or soul.
Yeah, a spiritual exoskeleton.
Yeah. So again I wish I had more information about this Nakala creature, but what is available does sound very tantalizing. So again, a kind of two faced crab monster that may exist sort of wild as a magical creature, but then also can but also can be created via magic to serve a sorcerer, and it eats men's souls, and it does so like from both ends at the same time, so two mouths simultaneously crunching down the soul or not the shadow, but in eating the shadow like destroys the body.
I think it's interesting that it's also said to have head. The two heads are like the heads of a hippo, which is you can actually think of some similarities between the hippo and the crab. They are both aquatic or semi aquatic creatures that walk, so they're like not fish.
They're not swimming creatures with tails. They have legs, but they live in the water, making them a kind of I don't know, in between type creature, and these in between creatures in our environments are often thought of to have kind of special or magical properties because they span the division between worlds.
Yeah. Yeah, and this does seem like a world rim walker for sure. So yeah, like I said, I wish there were more sources on this particular folk tradition, but what I was able to find sounded really really interesting.
That is really cool. All right, are you ready to do a bit of follow up on the Francis Xavier crab?
Yeah? Yeah, the crab with a cross? Yeah, what do we have this time?
Well, in the last episode when we talked about it, we said we might come back to the idea of how plausible it is that a crab would carry a cross a crucifix dropped in the ocean around in its claws over its head like it's described in the story. So maybe we should actually start a brief refresher on the story. So the story is a legend of the Catholic missionary and co founder of the Jesuits, Saint Francis Xavier,
and a crab. There are different versions of this story, but the best known goes like this, Xavier and his companions are sailing in the Molucca Islands when a terrible storm comes on and threatens direct the ship. Xavier prays for deliverance, and while doing so, he dips his crucifix over the side of the boat into the waves. In some versions of the story, he accidentally loses it it
slips from his hand into the stormy see. In later versions of the story, he sort of like throws the crucifix into the sea as a weather control bomb to still the waves. Whichever version you get, the crucifix is lost in the water. The ship survives the storm and reaches shore many miles away. And then the legend goes that while Xavier and his party are walking on the beach, a crab comes out of the water and approaches them,
and when it draws near, they see something amazing. Gripped tight in the crab's two claws, held aloft over its body is Xavier's crucifix, the one he lost in the storm. And then Xavier takes the crucifix and prays, and the
crab goes back home scuttles into the waves. So, based on what we covered last time about the development in general of the Xavier miracle stories, I don't think there's a strong reason to believe this anecdote actually happened, And there's also a chance, based on some scholarship we talked about, that it was inspired by a Buddhist legend, an older Buddhist legend of a ninth century Buddhist priest named Jakaku who uses an icon of a god of wisdom to
calm the waves and then gets that icon returned to him three years later by an octopus. We actually did discuss the relative likelihood of an octopus versus a crab bringing a trink it back to you from the water. I guess we still can't fully rule on which ones more likely, but I was leaning toward the octopus. However, I was wondering, would a crab potentially do something like this?
So we're not asking is the story true. I think there are just outside of the coreplausibility of the miracle, there are things about the story that make it unlikely to be true. But would a crab potentially do something like this, i e. Find a discarded crucifix on the ocean floor and carry it around overhead in its claws. So to answer this, I was like, well, what kinds of object manipulation and carrying do we see among crabs?
So I went digging into the scientific literature on different types of carrying behaviors, and I absolutely cannot provide an exhaustive list of every crab that's ever picked up and carried an object. But on the whole, I think you get a few major categories, and I'm going to run through them here. So one is decorator crabs. We've talked about these on the show before. This category includes several different species of crabs, all belonging to the superfamily Majoitia.
They pick up and carry thing. They pick up objects and carry them around, and these objects are not food, but they don't carry these objects in their claws. Decorator crabs mount objects to their backs, to their carapaces, often living sedentary organisms, though sometimes inanimate objects as well. So they decorate their carapaces with things like algae and soft coral anemonies and sponges, and they carry these things around. Those things, again, most often are living organisms, but they
don't carry them in their claws. So I think this is not really a relevant example.
Did we I'm trying to remember if we were talking about these crabs and discussed how in artificial laboratory environments they will end up picking things that don't make it seem to make less sense, like hamburger meat whatnot putting that on there.
Yet I think we did we maybe talked about that in our Bone Collector's episode, that they were they were just putting dead, dead stuff on their backs.
Yeah, so that would seem to me. This is not a not backing this up with any research, but based on what we've covered in the past, you could imagine an artificial scenario in which a crab, one of these crabs, is put in an aquarium without access to its preferred decorator selections, and instead is given various religious iconography. It might conceivably decorate itself with at least one of those icons possibly.
I mean, yeah, there are cases where these will they will put inanimate objects on their backs, like maybe shells or things like that. Yeah, so it's possible. Yeah, might might try to mount a crucifix on there. Now, the decorator crabs require they've got these almost velcrow like kind of hooks on there that are called I think ct on their carapaces, which are what they used to fix
objects to them. I have questions about whether that would actually attach correctly to whatever material the crucifix was made of. I think the story doesn't say what the crucifix was made of, but we had been assuming metal because if it was wooden, I like, would it sink? Though I guess. Also, I guess the story doesn't require that it sinks, just that it gets lost. So maybe it's a wooden crucifix that gets lost and then floats away, or maybe it's a metal one that sinks and then a.
Beef jerky or bacon strips.
I guess unlikely there, but attach the story doesn't say. But yeah, I had been I'd been thinking metal because I'd been picturing its sinking, but the story doesn't actually say it sames.
Well, and also there's the iconography where we see it metal like silvery, so that kind of forces you to think about the story like that as well.
Right, Yeah, So later they would make silver crosses of Saint Xavier Francis Xavior, where a crab is holding the silver cross in its claws, which is beautiful, holding it like Luke Skywalker holds the lightsaber. So okay, so you've got decorator crabs that doesn't really fit doesn't exactly fit the legend. You've got palm palm or boxer crabs. We've also talked about these on the show in the past. So crabs in the genus Libya do hold something other than food in their claws, but in this case it
is another living organism. This is another example of crabs symbiosis. The boxer crabs will hold usually stinging invertebrates like cea anemones, in their claws, and they use these for fence, for fighting, and sometimes for feeding. So they're sort of weapons. Yeah, they've got weapons of stinging stinging invertebrates on their claws. Then you've got the carrier type crabs. These exist in at least four families I was reading about. A big
example is the family Deripidy. These carrier crabs exhibit a behavior known as carrying. I was reading about it in a paper from nineteen eighty six published in the Journal of Crustacean Biology by Mary Kay Wixton called carrying behavior in brachiurine crabs. In this paper, Wixton documents crabs carrying objects around actually holding them up over their backs, but
it's kind of the wrong orientation. So these objects include quote shells, pieces of sponge, tunicates, algae, branches of Gorgonians or antipathians, or chips of rock. So we're starting to get closed. This is some times picking up inanimate objects like shells or rocks, holding them up over their backs.
But it's a little bit different than the imagery we see in the paintings and as described in the story, because again the Francis Xavier one it says it's got the cross in its claws, the clause meaning the killy the front claws. These carrier crabs do not use their claws the front claws as wixton documents. They carry things with their back legs, so like the fifth or fourth periopods, the furthest back legs which tend to be modified and
specialized for this job. And it's worth noting the biological function of this, both in the decorator crabs and the carrier crabs. The most supported explanation for why the crabs do this is for camouflage and defense. So they're basically hiding under these external objects and this may help them
lend in with the environment. It might camouflage them, but it also sometimes provides protection because they can take advantage of the defenses of a living animal mounted above like a stinging invertebrate again and then finally, Another possibly relevant example is crabs that build nests. There are various types
of crabs that do this. Fiddler crabs, I think ghost crabs build nests in the mud or in the sand, and as such they might sometimes carry or push, at least push around materials used in the construction of nests. This would be maybe things like mud balls or clumps of sand, though there's some blurring into the food manipulation category here because fiddler crabs will also use their front
claws for when they're dealing with mud. That is sometimes a feeding behavior, but none of the sources I was looking at described behaviors like clutching an inanimate object with both claws and holding it a So when thinking about crab behavior, we may be led astray by unconsciously comparing crab kili or crab claws to human hands, because we use our hands to carry objects all the time, but for crabs the claws are mostly used as tools, weapons,
and for display, not for carrying objects from one place to another, and most species of crab that carry objects do not use their claws to do it. So the closest I could get that really seems plausible to me is actually is some kind of carrier crab actually, but it would not be like the pictures we see where it's up in the front claws. It would be holding the crucifix over the back of its carapace with its back legs, and that is kind of an interesting image as well.
Possibly blasphemous though, holding the crucifer picks up with your feet. Well, I guess it's fine if a crab does it, it's all right.
Have we issued a Papa bull on this yet? Like? Are the are crabs holy? Or are they? Are they unholy?
I think crabs are absolutely holy, Okay, I think pretty much anyway you you take it apart, crabs are the children of God or the gods, and they do important work out there. I think the exception would be any kind of say black magic crab, demon or spirit that's summoned to, you know, for nefarious purposes. That I think would be more clearly some sort of artificial being.
The crabs, in attack of the crab monsters, are not holy. They have been rendered unholy by radioactive contamination and by becoming psychic mind stealers that eat you and steal your thoughts, right, so that it's hard to say that they're holy, but just regular crabs in the environment. Yeah, that's about that's got to be whole, right.
Yeah. Likewise, alien crabs or alien crab like beings from another world, well that's a whole theological discussion. To planets have individual gods or is there like one god that rules over all the planets? You know, that's not for us to decide. That's a much larger question.
All right, Well, I think we need to call it there for part two of our crab Bag series, but there will be more. We will be back with a crab Bag Part three at least on the following Tuesday. Is this going to be on a Thursday?
Yeah, yeah, absolutely, so look forward to more crab based action. Again, there's no shortage of crabs out there, real or imagined. Well, at this point, we just want to remind everyone. Stuff to Blow Your Mind is primarily a science and culture podcast. We've been around for years. You can find all of these past episodes in audio form wherever you get your
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