Speaker 1: Hey, welcome to Stuff to Blow your Mind. My name
Speaker 1: is Robert Lamb and I'm Joe McCormick, and today we've
Speaker 1: got an episode from the vault. This is another crab episode. Uh, Rob,
Speaker 1: you have titled it Crab content is king. I don't
Speaker 1: even remember what this was, but it had to be good.
Speaker 1: This was from last year where we had just done
Speaker 1: a two parter on crabs eating things. And when we said,
Speaker 1: you know what, let's have more crabs. Crabs are still
Speaker 1: eating things or doing other crab like things. Let's honor
Speaker 1: the crabs with a third episode. That's right, we did
Speaker 1: as we should have. So this originally published November. Here
Speaker 1: it is Welcome to Stuff to Blow Your Mind, production
Speaker 1: of My Heart Radio. Hey welcome to Stuff to Blow
Speaker 1: your Mind. My name is Robert Lamb and I'm Joe McCormick,
Speaker 1: and we're back from the break. We thought the best
Speaker 1: way to jump right back in would be to do
Speaker 1: more crabs. That's right. We had we'd just recently done
Speaker 1: a couple of episodes about crabs eating strange things, and
Speaker 1: we had some we had some crab run over anyway,
Speaker 1: so we thought, well, what what's what better than to
Speaker 1: go ahead and just jump right back in two more crabs.
Speaker 1: Crab overflow. Did you happen to eat any crab over
Speaker 1: the break rub? I went crabbing with my son and
Speaker 1: my and my brother in law, um, and they did
Speaker 1: catch crabs and they were excited about them. I ended
Speaker 1: up not eating any of the crabs, just because I
Speaker 1: don't know, I just wasn't feeling it. It's a lot
Speaker 1: of work. Uh, you gotta be you gotta want it
Speaker 1: so um. So I abstained from the consumption of crabs,
Speaker 1: but I did get to observe some crabs. In my experience,
Speaker 1: I feel like it's always kind of embarrassing to eat
Speaker 1: a crab. You're just sitting there working on it, you know.
Speaker 1: I guess it's all of the the intense concentration it
Speaker 1: takes to like crack the pieces and stuff. You're not
Speaker 1: really following the conversation of the tap able very well.
Speaker 1: It's you're in your own world. Yeah, I mean, it
Speaker 1: definitely is one of those activities that that puts you
Speaker 1: in the It feels like you put you in an
Speaker 1: archaic mindset. You know, you can imagine yourself, you know,
Speaker 1: you know, picking apart a carcass on some sort of
Speaker 1: primordial shore. Uh sort of a situation, and and therefore
Speaker 1: you do get in the zone. You get in the
Speaker 1: crab zone, right. Um, But I don't know that. This
Speaker 1: this year, I wasn't feeling it, so I did not
Speaker 1: have any crab but I was. I was in New Orleans, uh,
Speaker 1: and I did enjoy some some very nice food, uh,
Speaker 1: some very nice drinks. I made it over to Latitude
Speaker 1: once more and had some some drinks at beach bum Berries.
Speaker 1: Oh do they do anything with tiki turkey puns for
Speaker 1: for this time of year? Well, no, they get into
Speaker 1: the sip in Santa things. So there were some Christmas ones.
Speaker 1: I had a Christmas Eve of Destruction, which was very nice. Okay, okay,
Speaker 1: but we gotta talk crabs. That people want crabs. Yeah,
Speaker 1: let's get into crabs. So um, you know, in our
Speaker 1: in our most recent episodes on Crabs, I did dish
Speaker 1: out a little bit of crab mythology, and I mentioned
Speaker 1: how crabs don't often seem to have central rolls and
Speaker 1: myths and folklores for various reasons. But but that doesn't
Speaker 1: mean they don't have some very fun cameos. And of
Speaker 1: course I do hold out hope that there are some
Speaker 1: some other crab myths and legends out there that I
Speaker 1: just don't know about. And so as always, if I'm
Speaker 1: missing something, right in and let us know now. In
Speaker 1: The Eight Immortals cross the Sea, an important Chinese work
Speaker 1: of the Ming dynasty, you basically have the story of
Speaker 1: these eight powerful humanoid beings using their various powers to
Speaker 1: cross the ocean and kind of show off as they're
Speaker 1: doing it. Okay, I'm trying to is this something we've
Speaker 1: talked about on the show before or similar to it,
Speaker 1: or or a lot of these beings sort of uh,
Speaker 1: overlapping with the animals of the Chinese zodiac. I believe
Speaker 1: we've talked about the immortals before, but I don't think
Speaker 1: we've really looked at this particular work, okay, uh. And
Speaker 1: you might be thinking of the Chinese zodiac origin story
Speaker 1: about the the animal race where they have to cross
Speaker 1: a great river, so so this is different than that.
Speaker 1: But basically these are these are super beings. They have superpowers,
Speaker 1: and so they're showing off as they crossed the ocean,
Speaker 1: and crossing the ocean also entails outsmarting and overpowering the
Speaker 1: Dragon king. As this is his domain. And we have
Speaker 1: mentioned the Dragon King on the show before, but it's
Speaker 1: said that the Dragon King is served by quote, shrimp
Speaker 1: soldiers and crab generals, as this is the sea after all,
Speaker 1: And and I believe these these these sort of shrimp
Speaker 1: soldiers and crab generals also show up in tales of
Speaker 1: the Monkey King when when he encounters the Dragon King
Speaker 1: or the Dragon king soldiers. What is it about crabs
Speaker 1: that puts them in commander rolls? Don't? I mean, you're
Speaker 1: gonna put the shrimp in the commander roll? I mean
Speaker 1: it seems like a no brainer, right, But the thing
Speaker 1: is that in these stories the shrimp and the crabs
Speaker 1: are generally seen as ineffectual. So you have this saying
Speaker 1: that emerges from these tales. Any you have references to
Speaker 1: shrimp soldiers and crab generals. This has just become become
Speaker 1: a way of referring to ineffective soldiers. Uh so I
Speaker 1: kind of like that phrase. Okay, So would this be
Speaker 1: kind of similar to when people say tin soldiers like
Speaker 1: t I N I think so, yeah, I think this
Speaker 1: would be this would be a version of that in Mandarin.
Speaker 1: Now there's another Chinese crab myth that I was reading
Speaker 1: about that that was really fascinating me, and I wasn't
Speaker 1: really able to get quite to the bottom of it.
Speaker 1: But it pops up in yang and and Turner's Handbook
Speaker 1: of Chinese Mythology. It concerns the Yellow Emperor, and there
Speaker 1: are a lot of stories about the Yellow Emper and
Speaker 1: this one just happens to involve crabs. A lot of
Speaker 1: these emerge from from zin Jung in the Non province,
Speaker 1: and this one seems to have as well. And in
Speaker 1: this particular tale, the Yellow Emperor's attendants find a nice
Speaker 1: cave for him to visit in the owners So this
Speaker 1: is just just a really nice cave. It's cool, uh,
Speaker 1: you know some water there. You can rest very comfortable.
Speaker 1: Except they're way too many mosquitoes and other unwanted vermin
Speaker 1: living in the cave. So the Yellow Emperor just kind
Speaker 1: of casually mentions like, geez, I wish someone would drive
Speaker 1: these creatures away. Whish somebody would wipe these creatures out
Speaker 1: so I could enjoy this cave, because otherwise it's a
Speaker 1: great place to spend the summer. So what happens when
Speaker 1: an individual of great power casually mentions the desire well,
Speaker 1: oftentimes U uh, somebody will see an opportunity, and that's
Speaker 1: what the crabs living in the cave do. They hear
Speaker 1: this and they decide, well, let's do it. So they
Speaker 1: drive all the unwanted creatures out of this wondrous cave,
Speaker 1: and as a reward, the Yellow Emperor is said to
Speaker 1: have given these crabs an extra set of legs. Quote. Thereafter,
Speaker 1: only the crabs in the local pond have tin legs. Wait,
Speaker 1: I'm confused. Okay, so do you know anything about how
Speaker 1: this connects to to biology, because so crabs are decapods
Speaker 1: that should have ten legs, right right right? Yeah, this
Speaker 1: is where I really started scratching my head a bit,
Speaker 1: because yeah, that decapod crabs are quite literally ten legged crabs.
Speaker 1: So what would these other crabs have been? Well, I
Speaker 1: guess it seems to get complicated because technically decapods can
Speaker 1: have as many as thirty eight appendages, and generally the
Speaker 1: pereiopods are walking appendages or what we very loosely refer
Speaker 1: to as legs, and there are five pairs of those.
Speaker 1: But at the same time, many common crabs, such as
Speaker 1: ghost grabs, they do run around on four pairs of
Speaker 1: legs and sometimes actually only employ three pairs in running,
Speaker 1: and the fifth pair of legs or the claws, which
Speaker 1: we humans often go ahead and at least think of
Speaker 1: as hands, right, because we can make we can make
Speaker 1: a little crab claws with our hands, and so we
Speaker 1: kind of feel like those are the crabs hands, right, Yeah,
Speaker 1: And if you want to get really technical, I mean,
Speaker 1: crabs have all kinds of bilaterally symmetrical pen dig is
Speaker 1: that you could imagine our legs or have evolved from
Speaker 1: legs at some point. So you know, crabs have jaw
Speaker 1: legs in their mouths, the uh, the maxilla peds that
Speaker 1: help them eat and uh and yeah, so so yeah,
Speaker 1: it's true. Even though they will typically have ten legs
Speaker 1: or leg like appendages, some of those could be seen
Speaker 1: as other things. Like you're saying, you know, a person
Speaker 1: looking at a crab's claws as well, those aren't legs,
Speaker 1: those are hands, or looking at maybe the swimmer legs
Speaker 1: says those aren't legs, those are fins. Yeah. Yeah, because
Speaker 1: some crabs have paddles for their their hindmost pair of legs,
Speaker 1: so you can at least imagine a scenario in which
Speaker 1: someone might not count those as being part of the
Speaker 1: leg count. But um, but yeah, I'm not really sure
Speaker 1: how to exactly interpret this story that maybe there's something
Speaker 1: missing in translation. Um, you know, I looked around at
Speaker 1: a few papers about extra leg genetic abnormalities and some crabs,
Speaker 1: so maybe that's not out of the question either. Uh,
Speaker 1: maybe there's just something particular about the crabs in this
Speaker 1: cave environment or or even you know, is it sometimes
Speaker 1: the case and accounts like this in legends. Maybe it's
Speaker 1: not even describing a crab, it's something else, and the
Speaker 1: legend comes down to, you know, describing why does this
Speaker 1: thing look a little different than what we're used to? Well,
Speaker 1: because it did something wonderful and therefore was gifted extra appendages. Okay,
Speaker 1: what number of appendages? Does it become not that useful
Speaker 1: to have more of them? You know, if you've got
Speaker 1: if you've got two arms, having two more arms, that
Speaker 1: seems like a real upgrade, right, like Goro has got
Speaker 1: a real advantage over a regular human. But once let's
Speaker 1: say you already have uh ten bilaterally symmetrical appendages, if
Speaker 1: you get two more, is I mean, is that really
Speaker 1: an upgrade or do they just get in the way
Speaker 1: at that point, Yeah, I guess this is usually a
Speaker 1: question that that evolution natural selection solves over time. Right
Speaker 1: if if if appendages are not needed, well then they're
Speaker 1: just a drain on the the economy of the body,
Speaker 1: and therefore there's a there's a possibility they're going to
Speaker 1: disappear year over time, that they're gonna a trophy. So
Speaker 1: I don't know. But anyway, coming back to the story
Speaker 1: you were telling, I love that detail about the Yellow
Speaker 1: Emperor just sort of idly saying, oh, I wish someone
Speaker 1: would get rid of all these mosquitoes, because it kind
Speaker 1: of reminds me of the Actually don't know if this
Speaker 1: is historically solid, but the at least the at least
Speaker 1: legendary tale of the death of Thomas Beckett, the Archbishop
Speaker 1: of Canterbury, who when Henry the second supposedly said he
Speaker 1: was like mad at him, I guess, and said, you know,
Speaker 1: won't someone rid me of this meddlesome priest? And uh,
Speaker 1: it wasn't given as an order. He was just kind
Speaker 1: of musing about how mad he was. But some nights
Speaker 1: happened to over hear him and they're like, well, okay,
Speaker 1: I guess we gotta go kill this guy and they did. Yeah,
Speaker 1: basically seems to be the same situation here. Now I'm
Speaker 1: out of my depth on this, but I also can't
Speaker 1: help but wonder maybe part of the idea of the
Speaker 1: story is the crab has so many legs anyway, and
Speaker 1: therefore it's not much of a reward. I don't know.
Speaker 1: It makes me wonder, but I couldn't find out. I
Speaker 1: looked around. I couldn't find any other strong sources, you know,
Speaker 1: in in English on this. But if anyone out there
Speaker 1: has any details about strange crabs in a non province,
Speaker 1: crabs from the caves, and crabs with extra limbs right in,
Speaker 1: I would love to love to have more clarity on this.
Speaker 1: While you were telling the story, I was hit with
Speaker 1: a with a tremendously bad pun. Should I say it?
Speaker 1: Should I not say it? I don't know. It was
Speaker 1: little pinchers have big ears. That's good now, Uh, yeah,
Speaker 1: it's good now. There are there are other crab tales
Speaker 1: to be found in Chinese mythology. For instance, they are
Speaker 1: fairy old myths to be found throughout various myth cycles
Speaker 1: of China among different ethnic groups about the separation of
Speaker 1: heaven and Earth. Uh. This is of course something you
Speaker 1: see in in other myth cycles as well. Uh. And
Speaker 1: in Chinese traditions, sometimes there is a sky tower or
Speaker 1: sky pillar connecting the two, and sometimes an an moll
Speaker 1: is to blame for severing this tower or pillar. And
Speaker 1: apparently in some tellings it is a crab that does
Speaker 1: the snippet. Ah. Well, that would make sense. Yet again,
Speaker 1: when there's something to be snipped in a myth, sometimes
Speaker 1: the crab will fill that gap. Yeah. Now another one
Speaker 1: that I was reading about. This one. This is another
Speaker 1: you know, very old mythological tale, and it's the story
Speaker 1: of of woman Cho, of whom there are I think
Speaker 1: three narratives in the Classic of Mountain, Mountains and Seas,
Speaker 1: and as Zann Barrel explains in Chinese mythology in an introduction,
Speaker 1: the written versions of these tales UH date from the
Speaker 1: first century b c. E. And the first century see
Speaker 1: and they tell of a time during which quote, there
Speaker 1: are two people in the sea, but we only meet
Speaker 1: one woman Cho, who is strongly linked with the crab.
Speaker 1: And it seems like she may either take on the
Speaker 1: form of a crab or she has a crab that
Speaker 1: is her attendant, and it seems like this might be
Speaker 1: a crab of unusual size. And the reasons for this
Speaker 1: seemed to include the idea that okay, you've got the
Speaker 1: land and the and you got the sea, and you
Speaker 1: have the crab, which kind of has a dual nature.
Speaker 1: Like the crab lives on both. It can scamper on
Speaker 1: the beach, but then it can scamper beneath the waves,
Speaker 1: it can swim in the water, and so forth. Yeah,
Speaker 1: the dual nature is right there in its body. It's
Speaker 1: it lives in the ocean, but it walks on its legs.
Speaker 1: But then the crab also does another interesting thing. It molts,
Speaker 1: It sheds it's it's old shell and grows a new one.
Speaker 1: And this was seen as a kind of regeneration that
Speaker 1: might allow the crab to live forever. And it was
Speaker 1: also associated with cycles of the moon, and of course
Speaker 1: the moon has strong connections to the idea of immortality
Speaker 1: and Chinese mythology as well. Oh, that's very interesting, and
Speaker 1: it makes me wonder why we have commonly adopted the
Speaker 1: metaphor of the butterfly as the you know, the the
Speaker 1: important image from nature of something going through a transformation
Speaker 1: and then uh, and then coming out something new. I mean,
Speaker 1: I guess the difference there is that a butterfly looks
Speaker 1: very different than the than the larval stage that went
Speaker 1: into the pupa. But uh, but when a crab comes
Speaker 1: out is just bigger. So maybe that is a better metaphor.
Speaker 1: I don't know now. Woman Chow is also known as
Speaker 1: Woman Cho corpse, corpse deity and Uh. This is connected
Speaker 1: to drought and the time of the Ten Sons, the
Speaker 1: time in Chinese mythology we've mentioned on the show before, Uh,
Speaker 1: when there are tens sons in the sky and they
Speaker 1: are burning up the earth, as related in the Shanghai
Speaker 1: Shan quote. Woman child corpse was born, but the Tin
Speaker 1: sons scorched her to death. That was north of the
Speaker 1: land of Men. She screened her face with her right
Speaker 1: hand where the Tin sons are up above. Woman Cho
Speaker 1: lived there on top of the mountain, so she's she's
Speaker 1: scorched and burned by the surplus suns, perhaps seemingly especially
Speaker 1: her hand because she's shielding her eyes with that hand.
Speaker 1: But then she is later reborn in brilliant green, so
Speaker 1: she has renewal, she has drought survival, but she has
Speaker 1: also connected to these observations of the crab and the
Speaker 1: idea that the crab experiences this sort of periodic renewal
Speaker 1: as well. Now, another area concerning crabs that I was
Speaker 1: looking at kind of comes back to stuff we've talked
Speaker 1: about already about the you know, the idea that the
Speaker 1: crab design is a winning design, that it's emerged independently
Speaker 1: multiple times, and that according to some eventually everything will
Speaker 1: become a crab. Right, that's kind of the meme. Yeah,
Speaker 1: I think the more modest phrasing is that other crustaceans
Speaker 1: that are not necessarily crablike inform have repeatedly evolved into
Speaker 1: crab like forms multiple times in the history of life. Yeah.
Speaker 1: So earlier this year, Doug Johnson wrote a fun article
Speaker 1: for Ours Technica titled on Earth things evolve into crabs?
Speaker 1: Could the same be true in space? Uh? And so
Speaker 1: that part of this article is the author's generally summing
Speaker 1: up some of these ideas we've we've discussed already, But
Speaker 1: then he gets into this this issue of alien life
Speaker 1: because if we follow the logic that aliens might be humanoid,
Speaker 1: because that's what we see emerge as a dominant intelligent
Speaker 1: life form on our own world, then we might go
Speaker 1: as far as to wonder, well, if crabs are a
Speaker 1: popular form on this planet, wouldn't it make sense to
Speaker 1: see crab or crab like bodies crab morphs if you
Speaker 1: will on alien worlds as well. I want to believe so.
Speaker 1: Um Johnson reached out to one of the authors of
Speaker 1: the paper I referenced in our previous crab episode, Joe
Speaker 1: wool for researcher at Harvard University's Department of Organismic and
Speaker 1: Evolutionary Biology. The article was how does a crab become
Speaker 1: a crustacean? And I have to say absolutely love this
Speaker 1: quote from her. This is something she told to ours
Speaker 1: technical and in the the the interview quote there is
Speaker 1: no clear cut reason why being a crab is better
Speaker 1: than not being a crab. But if you say that
Speaker 1: too loud, the crabs in the cable here you and
Speaker 1: then they'll turn into something else. True. But I love
Speaker 1: this this quote because there's an absurdity to it, obviously,
Speaker 1: but it also does ring absolutely true and betrays a
Speaker 1: deeper understanding. You know, we don't have an answer in
Speaker 1: human reason and human language to the question here, but
Speaker 1: evolution provides its own answer, and the answer seems to
Speaker 1: be the crab form itself um in various examples. However,
Speaker 1: Johnson talks to Charles Marshall, director of the University of
Speaker 1: California Museum of Paleontology, and Marshall points out that all
Speaker 1: in all, it's a fairly narrow group of species that
Speaker 1: have become crab morphs on our planet. Um that you
Speaker 1: know that we shouldn't we shouldn't get too excited about this,
Speaker 1: this idea. It's like, well, crabs are everywhere, so they
Speaker 1: must be in space. Like there's like, ultimately, it's still
Speaker 1: a situation where the crab form has evolved as an
Speaker 1: answer to specific questions posed by our natural environment, and
Speaker 1: not say universal questions, right, And I think the other
Speaker 1: half of that, uh, The other important point highlighted by
Speaker 1: by Marshall's observation here is that it's not just that
Speaker 1: the natural environment creates some pressure that encourages crab like forms,
Speaker 1: but that it's also certain morphological starting places that if
Speaker 1: you're starting with a genome that codes for a certain
Speaker 1: kind of body plan, it's easy to get from there
Speaker 1: into a crab like form, and that body plan is
Speaker 1: like other certain types of especially marine arthropods, you know,
Speaker 1: certain crustacean types, right, I mean, like, for example, you
Speaker 1: can you can look at that the hands of various organisms, right,
Speaker 1: Like to get something like an extra finger or an
Speaker 1: extra thumb, it has to come from somewhere. You know,
Speaker 1: there has to be a starting point. It's not just
Speaker 1: you know, suddenly thumb sort of a situation exactly so.
Speaker 1: And maybe you know, another billion years, we could find
Speaker 1: that all kinds of mammals on Earth have evolved thumbs,
Speaker 1: because it turns out it's really useful for all kinds
Speaker 1: of animals. But you're not going to really find uh, say,
Speaker 1: crabs with thumbs, right, because they don't really have the
Speaker 1: morphological building blocks to start with to make thumbs, right,
Speaker 1: But I mean they do, they do sometimes have access
Speaker 1: to thumbs, because we do mention that they will show
Speaker 1: down on a cadaver. Yeah. Um, then again I want
Speaker 1: just to doubt what I just said. I mean, I
Speaker 1: guess depending on how expansive your definition of thumb is,
Speaker 1: you could say that a crabs claws, the pinching motion
Speaker 1: provides some of what a thumb is good for, right,
Speaker 1: That a thumb can help you you know, close your
Speaker 1: hand over an object in order to manipulate it, obviously
Speaker 1: with much more dexterity than usually a crab can. But
Speaker 1: I can see why we might look at the crab
Speaker 1: body and think, well, this might be good in in
Speaker 1: space because we look at the way the crab moves
Speaker 1: on land and through water, and it's easy to extracolate
Speaker 1: that toum like a micro gravity situation. Right. So, in
Speaker 1: the same way that you have some crabs on Earth
Speaker 1: who's whose rear most pair of legs has turned into
Speaker 1: swimmer legs, a little paddle legs to help them move
Speaker 1: through the water, you could imagine a crab whose final
Speaker 1: pair of legs has turned into ion thrusters. Well, I
Speaker 1: wouldn't go that far, but um I will say add that.
Speaker 1: I think another aspect of all of this is that,
Speaker 1: you know, we we tend to think of like crab
Speaker 1: more of popping up everywhere and imagine them in the
Speaker 1: future and another planets, because we do take a lot
Speaker 1: of delight in these organisms. I mean, they're weird, they're stealthy,
Speaker 1: they're efficient, they're kind of funny to look at. Uh,
Speaker 1: they're amusing to watch in the wild, and of course
Speaker 1: we like to eat some of them. Uh, so we
Speaker 1: have a vested interest in their existence, and that's always
Speaker 1: a great way to wind up as a noted animal
Speaker 1: for humans. Is it something that we eat or is
Speaker 1: it something that can eat us? And uh, you know
Speaker 1: that the crab kind of checks off both boxes, Uh,
Speaker 1: with some caveats on the the consumption of humans. That's
Speaker 1: a very well observed But I want to come back
Speaker 1: to crabs eating strange things, were being attracted to eat
Speaker 1: strange things at least, uh, And I wanted to do
Speaker 1: that by looking at a study I came across from
Speaker 1: just this year, looking at hermit crabs. Now we've mentioned
Speaker 1: hermit crabs a number of times in this series. Now,
Speaker 1: hermit crabs are decapod crustaceans. They're not considered to quote
Speaker 1: true crabs. I can't remember if we've said that already,
Speaker 1: but they belonged to the group and Amura meaning the
Speaker 1: false crabs, rather than bracky Era, which are supposedly true crabs.
Speaker 1: But hey, you know they're they're close enough there crabs.
Speaker 1: And so the study that I was reading about that
Speaker 1: I wanted to talk about was actually just published earlier
Speaker 1: this year. So in and It was by Jack Greenshields, Paula. Shermocker,
Speaker 1: and your Hartigaie in the journal Marine Pollution Bulletin. The
Speaker 1: authors here start by noting that bunch of research has
Speaker 1: identified a problem of marine life being in one way
Speaker 1: or another attracted to plastic waste. So we've talked before
Speaker 1: about some of the problems with plastic trash in the ocean.
Speaker 1: We discussed this somewhat in our interview with Christine Figner
Speaker 1: as it regards um, you know, the interactions between plastic
Speaker 1: waste and sea turtles. But plastic trash in the ocean
Speaker 1: is not just a sort of accidental collision problem, right.
Speaker 1: It's not just that a turtle happens to randomly swim
Speaker 1: into a bunch of plastic six pack rings that are
Speaker 1: floating along on the surface of the water. In many cases,
Speaker 1: it appears that animals that live in the ocean are
Speaker 1: actively attracted to plastic waste. That it is it is
Speaker 1: getting their attention in one way or another and disrupting
Speaker 1: their natural survival behaviors. And there are debates about the
Speaker 1: reasons for this. There are, of course, no doubt, different
Speaker 1: reasons when it comes to different types of plastic waste
Speaker 1: and different animals. So, for example, in some cases, visual
Speaker 1: mechanisms have been proposed maybe who knows, maybe a plastic
Speaker 1: bag drifting through the water looks like a delectable jellyfish
Speaker 1: and so forth. But in other cases the mechanisms can
Speaker 1: remain more obscure. And in this study, the authors were
Speaker 1: investigating a strange phenomenon in a hermit crab species called
Speaker 1: Pagurus bernardus, which is the common hermit crab or the
Speaker 1: soldier crab. This is a species that's native to the
Speaker 1: Atlantic coast of Europe and along the northern coast of Europe,
Speaker 1: basically the coast of Europe, but not really the Mediterranean
Speaker 1: uh specifically, this study I think was looking at the
Speaker 1: waters off of the eastern northern coast of England, so
Speaker 1: off of a place called robin Hood's Bay in North Yorkshire.
Speaker 1: I was actually listening to a radio interview on the
Speaker 1: CBC with Paula Shermacher, one of the authors of this study,
Speaker 1: and it was addressing the question of why were hermit
Speaker 1: crabs chosen for this study, and Shermocker says that hermit
Speaker 1: crabs are sort of a good model species to study
Speaker 1: She identified a few reasons. They're small, they're very curious,
Speaker 1: and they have quote a very diverse appetite, which I
Speaker 1: think goes with a lot of the things we've been
Speaker 1: saying so far. That you know, there are plenty of
Speaker 1: crabs out there, both true crabs and crab like animals,
Speaker 1: false crabs that that are not super picky when it
Speaker 1: comes to food types. They'll take what they can get,
Speaker 1: and hermit crabs often appear to fit that bill. They
Speaker 1: have a they have diverse diets and appetites. Yeah, I
Speaker 1: love that tidbit about hermit crabs, uh says. They they're
Speaker 1: they're interested in things that smell like food, but they're
Speaker 1: also interested in the site of another hermit crab appearing
Speaker 1: to eat something, so that that alone is is enough
Speaker 1: of a cue for them, right. But so, this research
Speaker 1: team was based out of the University of Hull in England,
Speaker 1: and what it found was that hermit crabs were attracted
Speaker 1: to the smell of a plastic additive known as olyamide. Now,
Speaker 1: oleamide is an organic compound. It's used as an additive
Speaker 1: agent in numerous plastic products. I was digging around trying
Speaker 1: to find out more about exactly what it's used for,
Speaker 1: And it looks like most often olyamide is used as
Speaker 1: a quote slip agent uh, and so this would be
Speaker 1: something that is added to a polymer to reduce the
Speaker 1: coefficient of friction on the surface of the material, basically
Speaker 1: to make the polymer more slippery. I also saw one
Speaker 1: of the authors here, I think it was in that
Speaker 1: CBC interview saying that it helps in some ways make
Speaker 1: the plastic more malleable. But it seems like the major
Speaker 1: use of it, from what I could tell, was to
Speaker 1: make plastics less grippy, to make them them a little
Speaker 1: slicker to the touch. And so you might wonder, well,
Speaker 1: why would you want that? Sometimes I think that's a
Speaker 1: desirable characteristic of plastic on the consumer side, But it
Speaker 1: also looks like slip additives are just important on the
Speaker 1: manufacturing side, especially with products involving thin plastic films like
Speaker 1: plastic bags and thin plastic food wrappers and packaging and
Speaker 1: things like that, and that adding these slip additives helps
Speaker 1: make it easier to like extrude the materials and then
Speaker 1: wrap them up tightly. But ollamide is also a a
Speaker 1: natural fatty acid. It's a natural organic compound that you
Speaker 1: know you'll find it in our bodies. It apparently has
Speaker 1: something to do with the regulation of sleep in in humans,
Speaker 1: and so I think has attracted some attention as a
Speaker 1: possible sleep aid, though I can't vouch for whether those
Speaker 1: UH alleged uses would be valid or not. But at
Speaker 1: least olamide naturally seems to play some role in the
Speaker 1: regulation of the desire for sleep in the human body.
Speaker 1: But again, it's also being used as this additive to
Speaker 1: help lubricate our plastics. And it turns out when you
Speaker 1: put oleamide into plastics, only amide can sometimes leach out
Speaker 1: from that plastic into the environment. So what happens if
Speaker 1: you're a hermit crab and you are crawling along the
Speaker 1: ocean floor and you happen to stagger into a big
Speaker 1: junkyard of plastic waste that is flooding the water with
Speaker 1: low concentrations of oleumide. Well, according to this study, surprisingly,
Speaker 1: if you're a hermit crab, that gets you really excited. UH.
Speaker 1: The authors of this research found that exposure to low
Speaker 1: concentrations of oleamide dispersed in water will cause an increase
Speaker 1: in the respiration rate of hermit crabs, and that this
Speaker 1: is a standard biomarker sign that that indicates excitement and attraction.
Speaker 1: Speaking to CBC Radio, Poulishrmacher again, one of the authors
Speaker 1: characterized the hermit crabs reacting to the oleamide as almost hyperactive,
Speaker 1: and so the question would be, why why do they
Speaker 1: get so excited and stirred up when they smell this
Speaker 1: plastic a additive. Well, basically it seems that they're reacting
Speaker 1: to olamide the same way they react when they smell
Speaker 1: a really exciting food stimulant. So this research was done
Speaker 1: in controlled conditions. But if if this in fact bears
Speaker 1: out into the natural environment, what you'd have to imagine
Speaker 1: is you've got some piece of very well lubricated plastic
Speaker 1: trash that is leaching oleamide into the sea water, and
Speaker 1: then a hermit crab smells it and then it kind
Speaker 1: of powers up, gets excited and heads toward the food source,
Speaker 1: only to find an inedible piece of plastic at the
Speaker 1: end of its hunt, which obviously is not great for
Speaker 1: the hermit crab, is because they should be spending that
Speaker 1: energy hunting for real food rather than than plastic that
Speaker 1: they can't really get nutrition from. So why would this
Speaker 1: compound used in polymer manufacturing cause a hermit crab to
Speaker 1: react as if it smelled food. Well, again, I think
Speaker 1: the answer is not known for sure, but the authors
Speaker 1: seem to have a pretty strong suspicion on that front,
Speaker 1: which is that only am i'd is chemically similar to
Speaker 1: olaic acid, which is a chemical that is released by
Speaker 1: the rotting bodies of dead arthropods. Of course, hermit crabs
Speaker 1: are arthropods as well, you know, these these related creatures
Speaker 1: with exoskeletons. So a hermit crab may well smell a
Speaker 1: plastic food wrapper that's been you know, tossed into the
Speaker 1: ocean's litter, and then it literally starts heavy breathing at
Speaker 1: the thought of the ripe dead body of an arthropod
Speaker 1: cousin that that it might be able to feast on.
Speaker 1: Because again, hermit crabs are scavengers. And this is what
Speaker 1: the authors call an old factory trap. All right, yeah,
Speaker 1: well this this makes sense. Yeah, it smells like shrimp
Speaker 1: death or a crab death or or what have you.
Speaker 1: They're going to be interested and go over there and
Speaker 1: check it out. And even if it's not, I mean,
Speaker 1: even if they want you know, didn't actually consume any
Speaker 1: of the plastic. Like you said, this is wasted energy,
Speaker 1: this is wasted scavenging that that should be spent on
Speaker 1: more lucrative endeavors. Right. So yeah, So to come back
Speaker 1: to the original question, that this is one indication of
Speaker 1: another way plastic waste in the ocean could be harmful
Speaker 1: to wildlife and showing a mechanism of attraction. In this case,
Speaker 1: it could attract these hermit crabs by way of additive leaching,
Speaker 1: possibly on the false promise of rotting kin flesh. Now,
Speaker 1: as to the question of whether the hermit crabs actually
Speaker 1: end up eating the plastic, whether they find it, I'm
Speaker 1: not sure about that. This study was just looking at
Speaker 1: them responding to the smell as if it were food.
Speaker 1: I don't know whether they would actually try to get
Speaker 1: it down the gullet or not. Another thing that I
Speaker 1: thought was worth flagging is there was an interesting case
Speaker 1: of miscommunication and some early science reporting about this study
Speaker 1: because a number of early articles about the study incorrectly
Speaker 1: claimed that the that the hermit crabs were sexually aroused
Speaker 1: by the smell of the plastic additive. That is not true.
Speaker 1: That is not true of her crabs. That seems to
Speaker 1: have been a miscommunication based I think out of the
Speaker 1: university press office where this study came from. But while
Speaker 1: this is not true for hermit crabs, it does appear
Speaker 1: that olamide is a constituent of the sex pheromones of
Speaker 1: some other organisms like cleaner shrimp. So you know, you
Speaker 1: can't rule out all possibilities. Maybe there are some Arthur
Speaker 1: pods in the ocean that would have some kind of
Speaker 1: sexual response to plastic additives than now, I was looking
Speaker 1: up more on the relationship between olamide, oleic acid, and decomposition,
Speaker 1: and uh I was reading a few things that actually
Speaker 1: reminded me of something we've touched on on the show before,
Speaker 1: which is the fact that oleic acid played a role
Speaker 1: in some classic research on ants by E. O. Wilson. Robert.
Speaker 1: I don't know if this rings a bell for you,
Speaker 1: but uh so, back in the fifties, EO. Wilson, the
Speaker 1: Great Entomologist, was studying harvester ants and their waste disposal behaviors,
Speaker 1: and so many ants have tremendous waste disposal capabilities. So
Speaker 1: ants will sometimes create a midden in or around their nest,
Speaker 1: basically a trash heap where they dump their garbage and
Speaker 1: the makeup of this midden can vary, but it will
Speaker 1: include everything from feces, to debris removed during nest construction
Speaker 1: or other behaviors, to the dead bodies of fellow ants
Speaker 1: from the colony. So you come across a dead ant
Speaker 1: in the colony, you want to get that out of there,
Speaker 1: and so the ants will take it away to to
Speaker 1: the midden or in some cases just away from the nest,
Speaker 1: but in other cases to this this trash heap and
Speaker 1: the middens containing the bodies of dead ants have sometimes
Speaker 1: been referred to as ant graveyards or ant cemeteries. They
Speaker 1: are somewhat creepy to look at. They're like a spider's
Speaker 1: web without the web. The process by which social insects
Speaker 1: remove dead relatives from their test is known as necrophoresis,
Speaker 1: and that that comes from necro meaning dead and phoresis
Speaker 1: meaning carrying or transport. But to bring this back to EO.
Speaker 1: Wilson in this somewhat famous story from the history of entomology,
Speaker 1: when EO. Wilson was studying this death transportation behavior in
Speaker 1: harvester ants in the nineteen fifties, he started to wonder
Speaker 1: how the ants could tell that one of their number
Speaker 1: had died and needed to be removed. What what was
Speaker 1: it that triggered the undertaker behavior in a certain in
Speaker 1: a certain subset of ants a certain period after another
Speaker 1: one of them had died, And so Wilson he figured
Speaker 1: that this likely was caused by by some kind of smell,
Speaker 1: a pheromone of some kind. In this case, it's something
Speaker 1: that would actually come to be known as a necromane.
Speaker 1: And he studied a bunch of different compounds that that
Speaker 1: could be released by a crushed or decaying dead ant,
Speaker 1: and he eventually found a winner, which was our old
Speaker 1: friend from from just a bit earlier, oleic acid. So,
Speaker 1: according to this story, he then tried an experiment where
Speaker 1: he got a bit of oleic acid and he dabbed
Speaker 1: it onto a live harvester ant to see what would happen. Okay,
Speaker 1: so this is one of these compounds released when an
Speaker 1: aunt is dead. Now an aunt is alive, but it's
Speaker 1: got this stuff all over it. And sure enough, he
Speaker 1: reported that eventually the tainted ant was grabbed by other
Speaker 1: ants and then treated as a dead aunt. So it
Speaker 1: was alive and kicking, but it was carried off to
Speaker 1: the midden for disposal. So basically he framed an aunt. Yes,
Speaker 1: he hung a sign on it saying I am a corpse,
Speaker 1: and the other aunts were like, okay, time to time
Speaker 1: to get to work. Um. Now, I think the happy
Speaker 1: ending of the story, if I recall correctly, is that
Speaker 1: after the ant spent a while cleaning the oleic acid
Speaker 1: off of its exoskeleton, it successfully rejoined the colony. So
Speaker 1: it just had to get all this stuff off of it. Yeah,
Speaker 1: I had, um, I remember reading about this or or
Speaker 1: we're seeing it covered in one the documentaries about Wilson. Um.
Speaker 1: I think one of the things I love about him
Speaker 1: is that, like, he clearly has a tremendous amount of
Speaker 1: love for ants, but it's a love that is based
Speaker 1: in how they actually function as organisms, more so than
Speaker 1: like anthropomorphism, because it's easy to love ants and you know,
Speaker 1: think in terms of of armies and you know, very
Speaker 1: human models of what they're doing and why they're doing it.
Speaker 1: But but Wilson, you know, I wouldn't go as suppost well,
Speaker 1: I would go as far as to say that Wilson
Speaker 1: like speaks and understands their language because because that that
Speaker 1: is a predominant area of a lot of his study,
Speaker 1: he understands how they communicate and and and and in
Speaker 1: doing so he has this this understanding of what they
Speaker 1: are and you know how they function. Oh, I totally agree.
Speaker 1: That comes through when you hear him talk about aunts. Yeah,
Speaker 1: that he he loves ants, not not by anthropomorphizing them,
Speaker 1: but loves aunts as ants. Let ants be ants. They're
Speaker 1: really good at it, and they're really the ast at it.
Speaker 1: I mean if you actually part of the problem is
Speaker 1: if you try to love ants by anthropomorphizing them, by
Speaker 1: imagining them as tiny humans, then their behavior becomes monstrous,
Speaker 1: Like humans should not be doing what ants do, but
Speaker 1: ants should do what ants do. Ants are great at
Speaker 1: doing ants. By the way, if you want more content
Speaker 1: on ants, we did a series about ant wars. Uh
Speaker 1: I guess it was last year, but you can find
Speaker 1: those those episodes. I think there are three or four
Speaker 1: of them in the archives. But so anyway, for for
Speaker 1: these harvester ants, oleic acid seems to trigger an instinctual
Speaker 1: behavior that says, hey, this object is filthy, rotting trash.
Speaker 1: Maybe you know it's some kind of garbage or it's
Speaker 1: a dead one of you, so it just needs it
Speaker 1: needs to be out of here, get it out of here,
Speaker 1: and take it to the midden. Now, in contrast with
Speaker 1: the other study with hermit crabs, I thought this was
Speaker 1: just funny because in so in these harvester ants, oleic
Speaker 1: acid means you know, I am dead, take me to
Speaker 1: the graveyard, and in hermit crabs, oleic acid and possibly
Speaker 1: only am I to because it is chemically similar, causes
Speaker 1: the reaction of you know, commence your heavy breathing. The
Speaker 1: buffet is now open. But in either case it appears
Speaker 1: to have something to do with death and decay. Is
Speaker 1: just the question of like, does arthropod death and decay
Speaker 1: signal to you a sort of an affection risk, something
Speaker 1: that's like whatever this is, it's it's it's not something
Speaker 1: we want in our colony, we need to get it
Speaker 1: out for hygienic purposes. Or does it signal something is
Speaker 1: potentially delicious and you know you're not going to miss
Speaker 1: up a chance to get some lunch. And apparently the
Speaker 1: use of alic acid is a type of signaling molecule
Speaker 1: conveying information about death and decay among arthropods. Doesn't stop there.
Speaker 1: Because I was looking at a study from two thousand
Speaker 1: nine published in the journal Evolutionary Biology by Yao at
Speaker 1: All called the ancient chemistry of avoiding risks of predation
Speaker 1: and disease. Uh. You know, so a cockroach can smell
Speaker 1: a dead or crushed cockroach nearby, and the researchers determined
Speaker 1: that it was primarily by the presence of a couple
Speaker 1: of fatty acids linoleic acid and oleic acid. Again, like
Speaker 1: we've been talking about using these, uh, these molecules as necromaneques,
Speaker 1: and the authors here separate the responses to these necromone
Speaker 1: cues into into two main categories so that they talk
Speaker 1: about what we were just talking about, the the necrophoric
Speaker 1: behavior of advanced to use social insects like ants, bees,
Speaker 1: and termites that will smell oleic acid or linoleic acid
Speaker 1: on on a dead member of their nest and then
Speaker 1: use that as a behavioral trigger to get that thing
Speaker 1: out of the nest or into the midden safely away
Speaker 1: from the activity of the other members of the nest. Uh.
Speaker 1: So that's necrophoric behavior. But then there are plenty of
Speaker 1: other arthropods like cockroaches apparently, uh, these would be classified
Speaker 1: as maybe semi social species that practice necrophobic behavior instead,
Speaker 1: so that's just avoiding the smell of death of their
Speaker 1: own kind. And the authors here were looking at the
Speaker 1: question of how where does this come from? You know,
Speaker 1: lots of different arthropods seem to have this behavioral response
Speaker 1: to these compounds. And so the authors say, quote, we
Speaker 1: hypothesize that necromones are a phylogenetically ancient class of related signals,
Speaker 1: and predicted that terrestrial isopoda that strongly aggregate and lack
Speaker 1: known dispersants would avoid body fluids and corpses using fatty
Speaker 1: acid necromones. These again would be things like like oleic
Speaker 1: acid or linoleic acid. And so the researchers here found
Speaker 1: that indeed, these these isopods were were repelled by several things,
Speaker 1: so crushed conspecifics. They were also avoidant of non crush
Speaker 1: just intact corpses of their own kind and alcohol extracts
Speaker 1: of the bodies of their own dead. And then they write, quote,
Speaker 1: as predicted, the repellent fraction contained olic and linoleic acids
Speaker 1: and and authentic standards repelled several isopod species. And then
Speaker 1: I think they also did some tests in other organisms
Speaker 1: tent caterpillars and fall web worms, and found that these
Speaker 1: creatures would would also tend to when they were siting
Speaker 1: their nests, they would avoid sites that smelled like the
Speaker 1: body fluids of their own conspecifics. And then finally the
Speaker 1: researchers found that just plain olaic and linoleic acids were
Speaker 1: strongly avoided by these creatures. So there are diverse types
Speaker 1: of arthropods across, you know, widely varying categories of life,
Speaker 1: that all seemed to have this necromone response. They smell
Speaker 1: olaic acid or linoleic acid, and that signals to them
Speaker 1: some kind of get away from this reaction. And the
Speaker 1: researchers here traced this back to aquatic ancestors of all
Speaker 1: these existing creatures uh that that lived probably more than
Speaker 1: four hundred million years ago, they say, at least four
Speaker 1: hundred and twenty million years ago, and this pre dates
Speaker 1: the the divergence of Crustacea and hexapoda, So modern terrestrial
Speaker 1: insects and crustaceans, which would include crabs, an ancestor tracing
Speaker 1: back to before those different categories of life split off
Speaker 1: from each other, probably developed this response. Though of course,
Speaker 1: at some point along the way, some creatures started reacting
Speaker 1: to oleic acid as as something to to be chogged
Speaker 1: down on. Wow. So there's you know, there's plenty to
Speaker 1: be concerned about with with with our over alliance on plastic,
Speaker 1: especially single use plastics. But in this we see a
Speaker 1: way that that plastics can end up um interfering with this, uh,
Speaker 1: with with the with the olfactory language of decomposition that
Speaker 1: is so rooted and established in the natural world, the
Speaker 1: hugely widespread chemical language. Yeah, that affects insects and and
Speaker 1: and crustaceans and and there are different responses to it.
Speaker 1: But if the researchers in that of your right, it's
Speaker 1: at least one of these chemical additives commonly used in
Speaker 1: plastic just happens to start saying words in this ancient language,
Speaker 1: and that kind of confuses that could potentially confuse all
Speaker 1: kinds of organisms. It's kind of like an alien probe
Speaker 1: or land on Earth. And it was it was, you know,
Speaker 1: just it was carrying out some sort of you know,
Speaker 1: function unrelated to human beings, but it also emitted a
Speaker 1: signal on an audible signal uh in English that said
Speaker 1: half off on electronics, um, you know, and and people
Speaker 1: would be then be drawn to it and they might
Speaker 1: be disappointed when they reach it and find out that
Speaker 1: it's it's just you know, terraforming the planet or something
Speaker 1: and not offering discount electronics. What what do you say
Speaker 1: on Earth that makes some people think, you know, death
Speaker 1: and decay, stay away, and makes other people think delicious?
Speaker 1: Um all you can eat buffet? I mean really that
Speaker 1: you don't have to go much further than that. The
Speaker 1: smell of packet French onion soup mix angels to some
Speaker 1: devils to others. You know, all right, all right, you
Speaker 1: never noticed that, Like some people smell that and it's
Speaker 1: just like the eyes go wide. It's delicious, and then
Speaker 1: I don't know, sometimes it just smells like armpits. Maybe
Speaker 1: hot dog water would be another example, you know, you know,
Speaker 1: depending on like you know, so many things. It's it's context, right.
Speaker 1: For many people, that's gonna it smells like, you know,
Speaker 1: a day at the ballpark. Other people are gonna be like,
Speaker 1: that's just that smells like like sausage meat has been
Speaker 1: soaking in there and and you know, in there for
Speaker 1: a day or so in a cart. How to hermit
Speaker 1: crabs react to hot dog water? I bet well, I
Speaker 1: bet yeah, I bet they I bet they they're very interested.
Speaker 1: They want to know more about it. All Right, well,
Speaker 1: we're gonna go and close the uh, the the crab
Speaker 1: trap on this one, but but we'll be back in
Speaker 1: the future, who knows what. We'll probably be back with
Speaker 1: more crab content at some point. Uh. They're probably not
Speaker 1: for for Thursday, but in the meantime, we'd love to
Speaker 1: we'd love to hear from everybody out there. What are
Speaker 1: your thoughts on uh, some of the myths and legends
Speaker 1: we talked about here, some of the environmental issues, and
Speaker 1: of course the behavior of crabs. Um. Oh. And on
Speaker 1: an unrelated note, I also just want to signal out
Speaker 1: another really fun thing to do in New Orleans that
Speaker 1: I did not know about until this previous break. Music
Speaker 1: Box Village. UM really fun place. It's like a imagine
Speaker 1: a like a kind of Junkyard playground environment where everything
Speaker 1: is a musical instrument and um and uh and uh adults, children,
Speaker 1: you know whoever, everyone when there is invited to sort
Speaker 1: of make sounds on it uh and creates this wonderful
Speaker 1: communal experience. They're also performers there. I just had a
Speaker 1: great time with it, so I just felt like I
Speaker 1: should I should share this, I should share this with
Speaker 1: the world. If you're not, if you're not familiar with it,
Speaker 1: I never heard of that. Yeah you can. You can
Speaker 1: look at up at music Box Village dot com. In
Speaker 1: the meantime, if you would like to listen to other
Speaker 1: episodes of Stuff to Blow Your Mind, you know where
Speaker 1: to find us. Uh Stuff to Blow your Mind podcast
Speaker 1: feed It's anywhere you get your podcasts. You get core
Speaker 1: episodes on Tuesdays and Thursdays, listener mail on Monday's, Artifacts
Speaker 1: on Wednesdays, and on Friday's we do Weird House Cinema.
Speaker 1: That's our time to set aside most serious topics and
Speaker 1: just talk about a strange film. Big thanks as always
Speaker 1: to our excellent audio producer Seth Nicholas Johnson. If you
Speaker 1: would like to get in touch with us with feedback
Speaker 1: on this episode or any other to suggest topic for
Speaker 1: the future, just to say hello, you can email us
Speaker 1: at contact at Stuff to Blow your Mind dot com.
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