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 in this episode, we're gonna be diving deeper on a topic that we first explored just a little bit on an episode of Automilia Stupendium, which of course is one of our shorties that airs on Wednesdays, and that is the subject of the Giant Clam. I found this to be a fascinating topic to explore because, on one hand, the giant clam is just an amazing organism, notable not only for its size but also for its unique symbiosis.
But in addition to this, it's an organism that has continually invited creative but highly inaccurate ideas about how they actually behave.
It's not hard to see why people might look at this thing and think that it will bite you, because it just looks like the whole thing is just a pair of jaws like cartoon teeth.
Yes. Yeah, And as we'll be exploring, I think the really interesting thing here is that you see this, this idea, this interpretation resonating not only with people who don't know any better. Who are you know, one or multiple degrees away from this organism and its natural habitat, but also people in close proximity to it, or just can be overwhelmed by the fact that it looks like a big mouth. What if it was like a big mouth? And what
would the consequences of that be. The most pervasive idea, of course, is we're talking about the idea that a giant clam might latch onto your leg while you were diving or snorkeling, or even in a very cartoon sense, swallow you whole. And to be clear, just to go ahead and get this out at the top, this has never happened. There's no recorded evidence of it ever happening, and for reasons we'll discuss, very good reasons. It pretty much never could happen. That's right.
There's like one real famous anecdote of a guy claiming that it happened, and he was there and I saw one of the babies and the baby looked at me. There are strong reasons for thinking that this story is not true, and other than that, it's mostly just vague generalizations from people not citing any evidence or fictional storytelling.
Right, right, Ben. You know that there are all sorts of things that can go wrong in the water, and there are lots of ways you can become injured and so forth, but this is not really one of them. And I think if you were gonna, if you were going to pin your death on a giant clam, it would be like you would have to essentially like strap yourself to the giant clam and die drown underwater. You would have to frame it in a major, insignificant way.
So yeah, in some ways, this I think is reminiscent of our recent look at manta rays in the ways that European sailors in particular misinterpreted the great fish as a threat. But again, the curious thing about the myth of the man eating clam is that while you only find it circulating in the nineteenth and twentieth century among Europeans and Americans, the idea also exists among native peoples, who would have had more hands on understanding of what
these creatures were all about. But again, we're susceptible to on one level, the kind of creative thinking, like you know, this can occur separate from a logical interpretation. You know, the idea that you know it's not a mouth, but what if it is a mouth? And I think we'll maybe get into a little bit about how maybe we're just hardwired to see the jaws that could consume us,
even if we know those are not jaws. So yeah, it just I think it might just boil down to the fact that a giant clam, especially just looks too much like a big old mouth for us to move past it.
And if you've never seen one of these, by the way, you can look up a giant clam or tridacna clam tridac na. These things have a waviness to their shells, you know, the way the shell closes it. It is not just a straight curved line across. It waves up and down like a you know, oscillation of a sound wave or something, which sort of suggests teeth and further lends itself into the mouth interpretation.
Now, speaking of mouths, it's interesting that tridacna apparently stems from the Latin for three bites, and this goes back to the writings of Like Plenty of the Elder and even the Conquest of Alexander the Great, where it was said that these could supply such meat as to require not one, not two, but three bites for you to consume it all. So the name actually originates in us eating them, rather than any fabulous reversal on that.
And people do eat them. By the way, A lot of people believe the meat of this clam is a is a delicacy. A lot of people think it's really delicious. This has greatly harmed the clams. They are now in a I believe, listed by the IUCN as a critically endangered species, and there were efforts at combating this by changing over some of the trade in their meat to like farmed populations instead of wild populations, receding wild populations
and things like that. But yeah, people are definitely getting some three bites in.
Yeah, because they're an important part of coral reef environments, the coral reef environments that they call home. Now, I was excited to look into giant clams. I hadn't really I didn't really have giant clams on my mind at all, because, aside from maybe in the background, I had kind of like a Looney Tunes idea of them, you know, swallowing a diving bugs bunny or something to that effect. But
as I've previously mentioned on the show. Over the summer, I had the privilege of visiting the islands of raja Ampat in Indonesia, where rich diversity of marine life, and this included the giant Tradacna clams, and of course the biggest of all Tradacna geigis, and a particularly large one in the area was known informally as Wu Tang clam.
And so I didn't get to dive right down to Wu Tang clam because Wu Tang clam was like a little deeper than some of the other than many of the other giant clams I was seeing, but it was still substantially large. And I included a photograph of Wu Tang clam for you here, Joe. I'm I'm like ninety nine percent sure this is Wu Tang clam. But this is a shot from down there at its level with proper lighting.
Oh wow, yeah, just looking at this one image here, it is so crusty with life all over it.
It's hard to.
See this as just one organism, as one clam with its two valves, you know, slightly parted. It looks more like a I don't know, a big piece of coral reef for something.
Well, that that underscores the reality here that yeah, they are reef builders in the long term, like you know, they settle, they grow there in one spot, and when they eventually pass on for one reason or another, you know they will be the bone of future coral reefs. So yeah, that's one of the reasons they're so vitally important to these environments.
Another reason, I think, Rob maybe you can confirm this because I guess you have seen them up close. I think sometimes people might not recognize they are looking at a giant clam, especially if they're like looking down from above, because it's not you don't obviously see the shell. You might just see a kind of ripply looking sheet of the inner flesh of the clam, like the mantle protruding
from out of the shell. Because in a lot of cases they will be perched somewhere in a kind of sunlit sea bottom and they're trying to spread out and gather sunlight on the fleshy parts. And we can talk about the reasons for that in just a minute here.
But you might not.
Actually see something that looks like a clam. You might say, what is this a big kind of flat ripple a sea cucumber or something. Because you're just seeing the mantle.
Right right, and the mantle tissue, it can be really eye catching. Certainly saw this a lot with the various giant clams that I was snorkling over. They almost feel magical at times, seeming to pulsate with a strange energy, and then they would as you would get near them, they would sense you for reasons that I'll get into, and the smaller varieties in particular would often kind of like maybe not close all the way, but kind of tense. Yeah.
They were very vibrant to look at, and to your point, yeah, they are. They are facing mouth up if you will, because the mansle tissue needs to be, you know, have maximum exposure to sunlight. Whereas the Looney Tunes version of the giant clam that might eat bugs, bunny that you tend to imagine it positioned less vertically and more horizontally.
You're right, because it's like a crocodile's mouth.
Yes. Yeah, So, as I was passing over these these clans, the interesting thing is I still knew enough about clams and giant clams to know that these things were not a danger to me. They were not actually going to try and bite me or anything to that effect. And yet there is this undeniable resemblance to some sort of a big fleshy mouth or secondary secondarily perhaps some sort
of yonic imagery. And so these associations I thought about this fair amount as I was passing over them snorkeling, Like, these associations connect with us, I think on a primal level, and it's hard not to at least casually think of what you're seeing in anthropomorphic terms, comparing them to basic human physiological analogues and analogs that are like very closely tied in to our survival and reproduction and so forth. Yeah, mostly we're going to talk about giant clams as mouths.
But on the subject of yonic imagery, we do certainly see interpretations of clamshells in general in the giant clamshell, as well as vulva in its use as fertility emblems as well as currency in some cultures in the past.
Sometimes you'll even see like Bodicelli's rendition of the Birth of Venus sided in there as well, though the shell that he depicts in that painting is a scallop shell, I believe, and not actually a clamshell, but it is presented on a scale that is more in keeping with a giant clamshell.
Though I think actually in that that's also bigger than any known giant clam.
Yeah, as we'll discuss giant clamshells, I think about the maximum you're going to get is like four feet.
Across, Yeah, which is very big, still very big.
It's still enormous. But you know, they can't fit a venus. Yeah, you couldn't fit a whole venus in there. You'd have to really scrunch your up. Still seashells in general, you know, pop up and Renaissance paintings, paintings sometimes with erotic suggestions and their usage. Though quite incidentally, there is a venus
genus of clam. I was reading about this recently. Eighteenth century Swedish naturalist and father of modern taxonomy, Carl Linaeus famously described the venus claim in quite sexual terms, which was pretty controversial at the time. Critics charged that he quote indulged in obscene illusions. Suffice to say, it seems quite a common interpretation, second only to the view of the clam as a mouth.
Was Linnaeus not otherwise really known for very expressive or controversial descriptions.
Correct. That's my understanding is that this was kind of an outlier where suddenly everyone was like, whoa, whoa, what are you doing? But you know, I guess the controversy died down after a while.
Yeah, it does seem like a biology is a funny domain to get upset about that in.
Yeah, yeah, all right, Well, speaking of biology, let's let's let's go through some of the basics of the giant clam here, particularly so again we're talking about for the most part, we're talking about Tridacna gaigis, and it can be found in coral reefs of the South Pacific and Indian Oceans. They can reach sizes of up to two hundred and fifty kerls are five hundred and fifty pounds, and they can grow to somewhere over four feet or
one point two meters long or across. So again, maybe not quite man swallowing size like we would see in our fiction, but still incredibly big. Like they still look like a they can still look like a massive like bio chest there on the seafloor. Yeah. Now, the giant clam, to be sure here, doesn't really have a mouth, especially in the way, you might read it as again the bugs bunny swallowing mouth. Instead, we have the valves, and
they are bivalves. Remember, so we have the like the two shells that essentially howls the organism, and inside they have a pair of siphons, one for drawing in food and water and another for expelling waste. Furthermore, they are filter feeders and they have no need for any jaw like mechanics. There's no chewing that takes place with the two valve. They simply close, or in the case of
the giant clams, nearly close their shells for protection. The giant clams can't actually close them all the way for a couple of reasons. And here's another big kicker. They close their shells exceedingly slowly. One of the main predators that they're closing their shells for protection against are sea stars, which you are quite a threat to a number of coral reef dwelling organisms. But they themselves are also slow
moving creatures. So for this very specific encounter, the closing of the shell is actually pretty fast, but it's as fast as it needs to be, and it's not man catching fast.
Yes, And the other thing you mentioned is they often don't close their shells completely because you will still see some of the flesh of the clam kind of protruding, like they've got to both expel water and retract their tissues inside in order.
To close exactly. Now, the varied colorization of the mantle tissues on the giant clam is due to ariticide cells that feed light to symbiotic single celled dinoflagelet algae or zooxanthellae. And this is where we get into the really cool
example of symbiosis going on here. The clam acquires these zooxanthellae via constant filter feeding in the water, it also acquires basic basic plectonic organisms that it actually eats, and thus, during the day the clam is going to open wide and extend its mantle tissue to absorb the sunlight necessary for the algae to conduct photosynthesis, and in return, the algae produced sugars and proteins that the clam needs to survive along with its more traditional filter diet, which it
requires less off. So the giant clam has a dual feeding strategy and this is thought to have evolved some sixty four million years ago.
Yeah, two different ways of eating. It is photosynthesizing with the help of these organized that it has absorbed and taken into itself. And then it's also filter feeding. It's sucking through water and filtering out little bits that it can eat.
Yeah, and so that's that's one of the interesting like observations you can make as you like snorkel over them. Is like that mantle tissue is like it really seems engorged, uh and and very out there because because it is, it is, you know, collecting sunlight, and yeah, so fascinating
that it has this dual feeding strategy. The giant clam also boasts thousands of pinhole eye spots along the mantle's edge that allowed to detect changes in light, not only the cycles of night and day, but also tailtale shadows of approaching predators. And so this gets into you know, the observation that I had as I was snorkeling over again, the smaller of the giants, they would sometimes like tense
up a little bit. They wouldn't close all the way, but there would be like a visual like rippling or movement of the mantle tissue and even the valves. Yeah.
Yeah, and I've seen video of the same thing happening. If you say, you move your hand over the top of one and cast a shadow over it, sometimes it will kind of tense and partially close.
Which, again the logical mind knows that, you know, it is just responding to the presence of another organism, which may or may not be something that is a threat to it. But you also can't help but illogically read it as like little mouths that are kind of going at you, you know. So again, I think it's almost impossible not to read them on additional levels as well.
Yeah, well, I mean I think the way to think of it is that what you're seeing there is a retracting impulse, not a biting.
Impulse, exactly. Yeah, it is a retracting not a biting Because yeah, I think the other way we tend to, you know, artificially think about them, and certainly in like modern looney tune sense, is to think of them as a bear trap. Yes, and we'll turn to some actual examples from twentieth century cinema that depicts them essentially as a bear trap just waiting down there for divers to pass through it.
Yeah, before we get to twentieth century cinema, there are older stories of giant clams. As you know various forms of monsters or man killers. The giant clam has appeared in some myths and legends of various people's of the Pacific Islands, sometimes as a benign creature, but sometimes as a dangerous or monstrous creature. One interesting example I found is in a to Amotuan version of the story of
the Polynesian hero Rata. I can't remember if Rata's come up on the show before, but Rata is basically a culture hero that you will find throughout Polynesian storytelling and lots of different Pacific Island cultures. There are Rata stories among the Maori, among Tahitians, to Emotuans, and others, sometimes with a different name a slightly different name in different regions.
The Rata stories differ in many details, but the most common elements are that he is a young, brave, resourceful hero who has to go on a dangerous quest to avenge the death of his father or to avenge some other kind of crime against his family, and in doing so he has to build a mighty canoe, which involves felling a tree protected by spirits or magical beings of the forest. Sometimes in older English sources these beings are translated as elves or goblins. More recent sources, I think,
will call them things like forest spirits or something. But once in this great canoe that he has made, Rada has to go on a journey, sometimes with companions, to avenge his family or avenge his father, and battle terrifying monsters along the way. And so in one version of the Rada journey, I found one of those monsters he fights is a giant clam.
So this is a.
Telling of a version found among the Tuamotuan people of the Tuamotu Islands and of Tahiti, told by a local scholar named Taroi to a Missus Walker, and compiled into a book called Ancient Tahiti by the British Tahitian folkloristan scholar Tearia Henry, who lived eighteen forty seven to nineteen fifteen. So I'm going to read the excerpt of the text, and of course I have to apologize in advance for any mispronunciations.
I'll do my best.
Here they were sailing on their course when the great au or swordfish came into sight, and Rata mistook it for land. But Tava said it was not land, but another foe. So Rada stood prepared again for battle, and when the monster approached the the canoe, intending to pierce it, he killed it with his spear and presented the body to the elves as before. Thus that demon was exterminated
and his flesh eaten by all. They sailed on, and they met the great Urua, the Kavala fish, which looked like land, but Tava told Rada it was the Kavala fish, sent by King Puna to kill him. The fish darted forward to carry away Rada, but he stood ready, and as soon as it approached him, he thrust his spear into its throat and killed it, and it was also eaten by all. Next they met the great Pahua Tutahi, a giant clam which appeared like a mountain looming up
from the sea. But Tava said, it is not land. It is the giant clam, and Rada prepared for the inevitable encounter. As his vessel was being drawn up into it. The clam had opened its great valves and was sucking in the waves upon which the canoe. Tua Rata was sailing. Stood at the bow with his spear, and as soon as they reached the center of the clam, he pierced it through its vital part, severing its flesh from the
shell so that it could not close upon him. He presented the clam to his spirit company to annihilate, and as soon as the canoe was safely away, the dead clam sank into the deep sea. So several interesting things here in the story. It sounds like he's talking about cutting the adductor muscle, which is something we see later when people are talking about how to fight this clam. In this case, it says that Rada, you know, he
stabbed it at its vital part with the spear. Severing its flesh from the shell makes it sound, and that prevented the shell from closing. Right, So it sounds like he is saying he attacked. He attacked the adductor muscle,
which the clam uses to close the shell. Another thing I want to note here is that I think there could be a temptation to take a story like this as evidence that the storyteller or the storyteller's audience would be expected to believe that giant clams are actually dangerous, that you know, they will come in eat your boat or something. But I'm not sure that's actually right. In this telling, the giant clam is not only a giant clam,
as in a tridacta geigis. It is a giant giant clam described as looming over the sea like a mountain and capable of swallowing an entire canoe. So to me, that doesn't necessarily mean that the teller of the story wanted to you to get the idea that a regular sized giant clam poses a threat to human beings, though that belief does appear to be common enough around the world at different times. Maybe you can't rule it out either.
But it might well be that the clam in this story is only understood as threatening because it is supernatural and monstrous and leviathan sized, not because regular giant clams are a threat. After all, the very next monster that ratafights in the story is a terrible demon bird that carried away Rada's parents and swallowed his father's head, and this is presumably not an indication of what the storyteller
thought about the offensive capabilities of regular sea birds. So I don't know that we can actually draw from this story a belief that giant clams would hurt you. It's just like, this is a monster giant clam. It might be no different than when we have Knight of aleipis a movie about monster bunnies.
Right, if if a bunny was that big, it would it would be a threat to us just based on its mass, similar to you know, we know that our housecat is not actually a threat to our life in a direct sense, but we can certainly engage in fantasies where it is enlarged or we are shrunken, and then that changes everything. Right, if a giant clam were supernaturally giant enough, it could it could filter feed us exactly.
Yeah, I don't want to be filter fed or filter eaten.
Now, why was this monster's flesh not eaten by all? Though? That seems like a missed opportunity.
That's a really good question. I don't know the answer. And anybody out there listening who's a scholar of toomotu and folklore who knows more about the Rata hero cycle, Like, what do you have an idea? Why was the clam not eaten like the other fish were?
I like a story where the people eat the monster we've encountered these sorts of stories before, and they seem very practical. I mean, sometimes the monster's body is poisonous by nature, and therefore, you know, it is left alone. But I like a story where they're like, okay, let's make use of this flesh.
And it's not just the hero. It's actually kind of heartwarming. The hero kills the monster and then takes it back and it's eaten by all.
Yeah, you know. And speaking of giant clams, I'll also refer listeners back to our episodes on the Fata Morgana, this being a mirage, an optical illusion that is seen at sea, which I did get to see an example of when I was in Indonesia. In Indonesia, but we discussed the Chinese myths concerning the shin or chin, which is a kind of giant clam, a giant giant clam,
to be sure, a supernaturally giant clam. And this one too, kind of emerges from the water like a mountain, but it also expels a fantastic phantasmagorical island, you know, that throws sailors off and people sail towards it and then they realize too late that this was not a real place. At all, but just an illusion cast up by this giant, this giant bivalve in the water. Yeah, but I don't believe it ever, you know, latched on or ate anybody.
So I kind of skipped over it otherwise for this episode. Yeah. Now, coming back to modern myths of giant clams eating people, I want to read an excerpt from Charles Frederick Holder. He was an American naturalist and conservations and he had a book in eighteen eighty five title Elements of Zoology, and this is time to understand otherwise for the time period, a very well regarded work. So this is again not
an example of like outrageous fiction. It is not an example of mythology or folklore, just you know, an attempt to present biological facts about the natural world. And in it he writes, quote, so powerful are they that large sharks and rays that have accidentally crossed them have been seized and held. That already gives us a lot to play. First of all, I've crossed them, I think just means has come close to them. I don't think this is
like a Vendetta situation he's describing here, right. He goes on to state that the tradacna always harbors within its shell several crabs. I actually couldn't find out out much about this other than to say that, yeah, you will find lots of animals living around and even among the valves of a clam like this. And then he also points out that the bisis this is the substance that like sticks. The clam to the rock is quote so large that it can only be cut with a hatchet.
And then he goes on to point out that eight species are known. So still the idea that the clam will latch on to creatures in its vicinity, including sharks and rays, which, as we've discussed, are very agile creatures that are not certain. I mean, it's one thing to even make the claim, well that a flimsy human snorkeler or diver might get trapped by one of these things, but it's quite another to imagine a shark or a ray being grabbed by something like this.
Yeah, but that's not going to stop you from telling a good story. I mean, so, there are lots of perpetuators of the myth of the killer clam. In the twentieth century, it came across many many things here that we can discuss. One great example of the idea that giant clams weregerous appears in a very short article that was reprinted throughout, you know, the publishing world, originally in the magazine Popular Mechanics in May nineteen twenty four. This
was volume forty one, number five. I saw a vague reference to this in another article and I had to go dig up the original text, and I'm glad I did, by the way, because this entire issue of Popular Mechanics is hilarious. This is sort of a digression from the clams. But I have to discuss a few highlights from this nineteen twenty four pop mac one headline tear gas in police clubs to foil bandits. What The article claims that it is impossible to remain within ten feet after the
gas is released. So it says, you know, you hit the bandit with your mace or billy and it releases the tear gas. And I was like, what about the person hitting with it? I guess they have to be wearing a gas.
They just have to be gas masked up from the get going.
What it's in the club? That was inside the club?
Uh.
The other thing is the headline baking as cure for dog ills is tried in Germany and Rob here's an illustration for you to look at. Well, not a photo of a guy who's got a dog, and it's just labeled dog being baked in gas. Of Now, I have to c it's not saying that you bake it at like cooking temperatures. I think it's just like kind of like a steam bath. It's like very warm in there.
Like a cartoon steam bath where you would have a cartoon character get in and only their head sticking out. That's exactly what they're doing to this dog. That headline really is a roller coaster because when I first read it, I was like, oh, well, that's kind of nice. You're baking for the dog, you're making little cookies or you know, little treats. But no, this dude has a metal contraption that this dog's body is stuck in.
So this poor dog's just looking like I'm very hot.
Yeah.
Another one. Here's the headline. Forty pound cigar is valued at seventy five dollars what is said to be one of the largest cigars ever made. One of the largest was shown at an Eastern Tobacco exposition and it goes on to, yeah, not really say anything else except that it's valued at seventy five dollars. It does not answer the question did anybody smoke it?
And it's so weird looking at these because my grandfather in the I guess this is in the eighties and nineties, he always had he had always had copies of Popular Mechanics and Popular Science sitting around and I would look through them as a kid, and you know, these felt like they were accurately depicting the future. There are always articles about, you know, new gadgets, new upcoming technologies. So it's quite a trip to explore these these previous stories in Popular Mechanics.
Skeptical editorial standards might have been improving as the decades went on. Maybe anyway, onto clams. So in this wacky Popular Mechanics, there's one article titled Giant clams trap sea divers in Grip of Shells. It's a very short article, so I can read it in full. It says shells of huge clams found off the coast of Papua often
weigh more than four hundred pounds. Divers who accidentally step into the open lips of the monsters are not infrequently held with such force that they cannot release themselves and are drowned. The shells closed with such force that they
serve as gigantic traps. That's the whole article, except for there's a photo of a giant clam, and we see the characteristic shell with the with the wavy line of the mouth, and the caption is giant clam and coral reef off New Guinea, powerful crushing lips, partly open.
The interesting thing here is, though it's described as partly open, this is actually probably a situation where they're as closed as they are going to get. Yes, And they're describing giant clams, by the way, in exactly the area that I was snorkling in.
Oh that's funny.
Now.
The text of this popular mechanics article seems to have been reproduced in newspapers and other publications in the nineteen twenties, so it seems kind of like this story really got around in the following decades, including in various bits of pop culture. This exact clam trap scenario is depicted in a scene from a nineteen forty eight adventure film called Wake of the Red Witch starring John Wayne himself and Gail Russell rob I put in a link for you
to look at the scene if you want. It's actually, I don't know, it's not that remarkable as a scene, and it's really hard to see what's going on in the underwater photography. It's very murky. Basically, the movie is a revenge story about this deadly feud over a woman between a bitter ship captain played by John Wayne and a wealthy shipping company owner played by Luther Adler. I haven't seen the movie in full, but yeah, I found a clip of this clam scene. Basically, a kid goes diving.
He accidentally sticks his leg into a tritachna clamshell. The shell slams shut and traps him by the ankle, and then John Wayne has to dive down and do battle with the clam to get it to release the kid. He succeeds by with the kid's foot still inside the shell. By the way, by John Wayne, he stabs into the gap in the clam's shell with some kind of spear almost looks like a glave, and I was like, he's gonna stab the foot, but the kid's okay.
This shell in this movie, by the way, just it looks like a giant quarium clam. You know the kind of little clamshell that opens and closes in your standard a quar Yeah, it's like bubbles. Yeah, it looks like it's made out of plastic or something like plastic. And also like no visible or at least I didn't see any visible mantle tissue either.
Another great example I found from popular our culture is Superman versus giant clam. There are actually several instances of this. The theme that is usually emphasized is like, wow, Superman is so strong he can even pry apart the jaws of the killer clam. That would take a mightiness born only of his Kryptonian blood interacting with our yellow sun. So the main example I came across is that Superman fights giant clams in one arc of the Adventures of
Superman radio serial. This was a I think it was a six episode series called The Curse of dead Man's Island which ran from September to October nineteen forty and in this encounter, they're on a mysterious island and Jimmy Olsen and another character are swimming to shore after their motor boat has been wrecked, and they get attacked by a swarm of fast moving giant clams. Yeah, these clams they not only clamp down and trap you, they actively
chase you, is what it sounds like. Don't remember the exact wording, but it's like they're coming right for us.
They're like wind up chattery teeth.
Can we get a can we get a sample of this jjuting.
The waters clear?
I've got to work fast before I would drown.
Wally shells apart and fleet these things are powerful.
Oh wow, only the Man of Steel has hands strong enough to wrench apart the deadly molluscian grip. And I love how you can hear Superman like grunting and groaning and saying.
Great Scott.
These things are powerful. And then there are also some some visual like Superman comics where he has to fight a giant clam. There's one. I actually was not able to figure out what issue this is from, so I can't say, but I found it just like a clip on Google image searches, where it looks like it's a silver age Superman who's having to he gets his own foot stuck in a giant clam's mouth and he has to like shoot it with his eye lasers.
And this is another example of the comic book giant clam is more horizontal, yeah, positioning as opposed to vertical. Yeah, you mentioned that film from nineteen forty eight. I ran across another film from nineteen forty eight that also features pretty much the same giant clam gag, and that's the film sixteen Fathoms Deep. This one starred Lloyd Bridges as well as Lawn Cheney Jr.
This one has a lot of narration. I don't know who's narrating, but I watched the scene you sent me, and like, it's the exact same thing. A kid goes swimming, clam bites his leg, somebody has to swim down and rescue him, though it looks a lot easier this time. The person who swims down and rescues the kid and the clam just kind of pulls him out.
Yeah, he just goes down and negotiates the situation. That's right now.
All this twentieth century killer clam stuff, when you look into it, it's not like really claims based on anything specific. There are claims that are supposed to be authentic, but they're just vague generalizations. And then there's also pop culture. But are there any actual, specific, first hand accounts of giant clam attacks in the twentieth century. There's one main one,
though it will come with some major caveats. So a lot of these stories seem to trace back to a figure named Wilburn Dowell Cobb, an American who wrote an article called the Pearl of a Llah in the November nineteen thirty nine edition of Natural History magazine. Cobb was at the time he wrote this article the owner of a massive clam pearl. And I'm not fully up on this distinction, but I know gemologists make some kind of distinction between clam pearls and some other kind of pearls.
I'm to understand that this thing is huge enough to be considered really, you know, notable and valuable, but that generally clam pearls are not as prized as like the iridescent kinds of pearls you might get from pearl oysters.
Right, that's my understanding as well. The basic the composition is different.
Yeah, but Cob was the owner of this gigantic clam pearl. He originally called it the Pearl of Allah. He later renamed it the Pearl of laod Zoo. Which at the time this article was written, this pearl was advertised as the largest pearl ever found in nature. Cobb claimed that he acquired it as a gift from a pearl diving family in the Philippine province of Palawan in nineteen thirty four, and so his story goes like this again. After this, I'm going to come back with some reasons for doubting this,
but this is what he says. He says that he was visiting a small diac fishing village on an archaeological expedition with some companions. Now, I was a little confused about the terminal he was using to refer to the people here, because from what I understand, the term Diek is usually used to refer to the largest ethnic group in Borneo, not to the people of Palawan. I'm not sure what accounts for this, but anyway, he says, one night he was awakened by a great commotion and it
seemed to be a funeral. Dirge Cobb's guide explained that his own son, who was the village chief, bog Tong, had organized a dive to collect conk shells, which the villagers planned to trade at market for some much needed new fishing equipment. But after several dives, bog Tong realized one of his best divers, a man named Etim, was missing.
And then here I'm going to read from Cobb's article, he writes quote, Suspecting a giant octopus, they unsheathed their knives and as one dove down in search of their missing comrade. On the fourth dive, they found Etem already dead. In his search for conk shells, he had failed to see the giant tridacna clam, which was partly hidden by coral rocks, its huge jaws held open ready to clamp
shut with the strength of a bear trap. Attim accidentally got his hand between the shells, which snapped shut, and thus he met his death. With the aid of ropes, the men hoisted their dead comrade and his deep sea murderer into one of their canoes.
Deep sea murder. Again, these are generally found in coral reef environments.
Right, So Cobb claims that this clam, which was brought ashore, was later revealed to contain a gigantic pearl, and it was The pearl was first claimed by a local Muslim chieftain, but then given to Cob as a gift after Cob
managed to save the chief's son from a deadly illness. Again, this is all his own account, so there is at least a first hand account of a giant clam snapping down on somebody and drowning them, and the pearl itself is actually real, but the story of where it came from that has met with intense scrutiny from later reviewers. I didn't have time to chase down all of the
different investigations of this. There have been several, but it seems that multiple later articles point out serious reasons for doubting the story, including the fact that Cobb changed major details of the story over time. There was no corroborating evidence or documentation of this from the Philippines, and Frankly, while well this is just subjective and doesn't really bear any evidential weight, I have to say just because I
noticed it myself. If you read Cobb's article, it has a fabulous texture in the pros it reads like a guy making up a story to make himself sound cool.
Yeah, it sounds a little carney. It sounds very much like someone selling the lore of the thing he is literally selling.
Yeah, if you want to read more, about this. There's an article in the Atlantic called The Pearl of Laosu by Michael LaPoint from twenty eighteen, and that gets into the whole history of this pearl and also what happened to it, because there was also some ownership controversy after Cobb.
Another commonly repeated claim when people are writing about this idea that giant clams will attack people or clamp onto them and trap them underwater is the claim that US Navy diving manuals of the twentieth century portrayed the grip of the giant clam as one of the perils of working on the bottom. For example, there's an article that I think you referred me to rob that was in
Atlas Obscura. It's about giant clams, but it's actually it's an excerpt from a book by an author named Cynthia Barnett. The book came out in twenty twenty two and it's called The Sound of the Sea, Seashells and the Fate of the Ocean. In this excerpt of the author rights quote, the stories captured the imagination of the US Navy during World War Two, when soldiers fighting in the Pacific were briefed on the man eating clams and large sharks known
to inhabit the reefs. The man eater myth was so persistent that decades later, navy diving manuals still advised frogmen how to free themselves if caught in the vice like grip of a giant clam, by inserting a knife between the valves and severing the animal's a ductor muscle.
Yeah. I ran across this tidbit and a couple other sources I was looking at as well. But again, but in terms of finding the original material, I couldn't couldn't really find anything.
Yeah, I have no reason to doubt Barnett. I'm sure it is out there somewhere, But unfortunately I wasted a lot of time searching in vain for the primary text here. I was looking through navy diving manuals of the forties, fifties, and seventies, and I never found any references to clams. In fact, I couldn't find anything at all really about
dealing with wildlife. The sections on dealing with hazards and working on the bottom are highly concerned with various forms of entrapment underwater, But it looks to me like the most pressing concern is what's called fouling, which is when the diver's lifeline or air hose gets caught or tangled on something on the bottom, like rocks or wreckage, and this is very dangerous because it prevents the diver from
safely ascending. I found very little about the diver themself being caught bodily, though in terms of threats to your own body orientation, there are concerns about getting knocked over or tripping and falling on a dive because in this era, divers would wear a heavy metal helmet applied at the surface, kind of like what you see in BioShock, and you had to remain upright during a dive or you could risk the possibility of flooding the helmet, which was very,
very bad. So for divers of this period, the real monster you have to fear is not a creature that lives in the sea. It's hydrostatic pressure, yeah, pressure and equipment failures. That's like the main thing to worry about. So not only did I not find any references to clams, it just seems like wildlife is like so far down the list of concerns, like the thing that they're really getting into the the diver's heads here has to do with with dealing with pressure and using your equipment properly.
That's right, Yeah, yeah, pressure equipment issues, the threats posed potentially by other boats if they're not aware of your presence, things like that. Yeah, you know, to be clear, I mean, there are various threats in the water posed by organisms, but a certainly the giant clam doesn't really rank highly among them. And I mean there's even a case to
be made this references here. I'll point outs in reef environments and you know, when I was in reef environments in raja Ampat, there are sharks around, but they were not interested in us at all. So it does make me wonder. Okay, if playing Devil's advocate, let's assume that there actually was reference to this in US Navy dive manuals of the time period. You could look at it
in one of two ways. Either, Okay, there this idea was taken up that these organisms were potentially a threat and therefore you needed some sort of a plan of action should the threat arise. But maybe also a part of it could have been Okay, we're training up a lot of a lot of landsmen here to go into
the water and do things for the Navy. They're going to have concerns about organisms in the water because they've been watching movies or reading comic books or listening to radio programs, and or we just have a natural aversion to large, strange creatures in the water. Understandable. And maybe part of that was like, Okay, there's no reason that the giant clam is actually a threat. There's no reason that even some of these sharks are necessarily a threat.
But we need to have give them a plan of action so they'll feel more at ease in the water knowing that there is something they can do if this, if this event were to transpire.
Yeah, well, you know, I wouldn't say, based on what I was reading, that a giant clam would never be a threat. But I would say that it doesn't appear to me that the main threat would be that it would close upon you. It would be that you would It would be the same threat as like a rock or a reef on the ground, which is fouling you would get your lines tangled on it.
Yeah, yeah, I would. I would agree with that, treating it essentially like like any other large structure or rock or piece of coral in the water.
So beyond all this, I checked around, and from what I can tell, the killer clam story is universally agreed among experts a marine biologists to be without merit. There is no solid evidence anywhere of a single example of a person ever being killed, seriously injured, or trapped by a tridachna lam. Marine biology resources stress again and again that, like you were saying earlier, Rob, the clamshell can close defensively,
but it tends to close slowly. It has to expel water to do so, and it has to retract its own flesh, which tends to protrude out of the gap in the shell. So apart from Cobb's story, which there are serious reasons for doubting, there's no documented account anywhere of a giant clam actually harming anyone.
Yeah, you'd really have to, like Homer sense in your arm in there, Like Sarah, you just just holding on to the inside of the clam. You're just holding on to the mantle tissue, and you say, yes, actually that's what I'm doing.
Well, yeah, I mean, I guess the other thing to say is that it has never actually happened that we know about in any verifiable way. Is different from saying it couldn't happen if you did something really stupid right like I don't know, if you like, maybe if you really like shoved a boot down in there and you forced it to stay inside while the clam was closing, and until the clam had closed around you, it might be hard to get it back out.
I don't know, but that.
We have no examples that are verifiable that this has happened.
Don't try to be the first. I feel like you'd really have to try. You'd really have to get in there and really tempt fate and try to make this happen for yourself. And you know, I guess there's one way to go down in the history books, but surely there's a better option. You'd have to again, essentially frame a giant clam for murder, which I don't think is fair.
They don't need any more trouble there. I mean, they're having a hard time, they take a long time to grow, they've been over harvested. Giant giant clams need a break.
Yeah, leave them be, keep a respect respectful distance, but by all means observe them if you get the chance. Like I say, it was it beautiful and weird to be in their presence. I can't stress both enough. Again, their mantle tissue is beautiful, their size alone can be
quite a spectacle. But there is also something kind of weird, because again we can't help but read them as analogs of human physiology, and it's, you know, weird that they're kind of like smiling up at us from the from the seafloor.
Smile back, yes, get out of their light.
All right, Well, I think that's going to do it for this episode. But of course we'd love to hear from everyone out there. We've heard in the past from
snorkelers and divers, you know, with lots of experience. So I know we have some snorkelers and divers out there who have more experience with giant clams or clams in general, and might want to chime in with their own expertise, observations, or you know lore that you've heard from maybe fellow older divers and snorkelers about giant clams, whether it's pure
mythology or fact base. We'd love to hear about you, So write in just a reminder that stuff to Blow Your Mind is primarily a science and culture podcast, with core episodes on Tuesdays and Thursdays. We have short form episodes on Wednesdays and on Fridays. We set us like most serious concerns, to just talk about a weird film on Weird House Cinema.
Huge thanks as always 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 at stuff to Blow your Mind dot com.
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