November 18, 2021 • 50 mins
In this episode of Stuff to Blow Your Mind, Robert and Joe talk about crabs eating things. Do YOU have what it takes to become a delicious entree for crab gourmands? Find out!
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Speaker 1 (00:03):
Welcome to Stuff to Blow Your Mind, the production of
My Heart Radio. Hey, welcome to Stuff to Blow your Mind.
My name is Robert Lamb and my name is Joe McCormick.
And we're back with part two of the Feast of Crabs.
If you haven't heard part one, you should probably go
(00:23):
back and listen to that one first. But I'm ready
to jump right in. Yeah, we're gonna We're gonna continue
with our exploration of various uh accounts of crabs eating
curious things, eating things in curious ways, and so forth.
This is kind of our big kome of tradition during
the holidays towards the end of the year to dive
(00:45):
into a crab related topic and see what it has
for us. Now, we haven't talked a lot about mythology
and folklore in in our crab journey thus far. And
you know, part of it is when you look around,
crabs often don't have central roles in um in myth cycles.
I mean there, I think there's some exceptions to the rule,
(01:07):
but a lot of times it's stuff like like Hercules
is fighting the hydra and then a crab shows up
and tries to to to nip at his heels and
he dispatches it and goes back to fighting the hydra
that sort of thing. Oh yeah, that sounds it was.
So that's the crab cancer, right that we can the
constellation name from, or that has the same name as
the constellation. I mean, he still gets a constellation out
(01:29):
of the whole affair. But it's you know, it's it's
it can feel a little bit disappointing if you're really
into crab anatomy and into crab monster movies. Um, it
can be a little a little bit of a letdown, like,
come on, you can't Hercules have more of a battle.
Can't he just battle the crab? That sounds fun to me.
Oh wait, I just had to look this up because
(01:50):
I wasn't sure if I was remembering it right. But yeah,
he he gets the constellation basically because Hara hates Heracles
and the crab like bites him on the foot, and
then Heracles kills the crab, and Hera is like, well,
good job biting him on the foot. I'll put you
in the sky forever. The Greek gods. Well, I do
(02:12):
have a fun one that I found though, that I
want to share with everybody. This one I discovered in
the book Japanese Mythology A to Z by Jeremy Roberts.
I looked around to try and find in some other
places as well and didn't off hand. Um, I'm sure
it can be found other places, but this is the
only place I was able to find find it. I'm
going to retell it for you here, but I'll stress
that Jeremy roberts telling of it is is going to
(02:35):
be more dramatic than mine, So definitely go to that
source if you want to see it for yourself. So
that is how it goes down. A young girl, uh
buys a crab from a fisherman in order to save
the crabs life. She's doing you know, that basic thing
that a lot of little kids will do, where they suddenly,
you know, they'll feel sorry for a captive animal or
a food animal and they want to to save it.
(02:57):
And so that's what this girl does. She buys the crab,
lets it go. Meanwhile, her father is in a similar scenario.
He's trying to save a frog from a snake. I'm
not sure why, but he's trying to do this. He's like, no, snake,
you do not get to eat this frog. I'm not
gonna let you do it, and the snake finally is like, okay, look,
(03:18):
I'll spare the frog's life, but you have to let
me marry your daughter, and Dad agrees. So we we
don't know anything about this frog. It's not special, like
it wasn't his brother who got turned into a frog
or something. There has to be more to this story. Um.
You know, I've been reading a lot about various yokai recently,
(03:40):
and you know, with with those Chinese ghost stories, there's
often some hidden meaning. You know, maybe it comes down
to a turn of phrase, you know, something that's not
going to be obvious in a pure English translation, or
it's something metaphorical, etcetera. So I don't know exactly what
is going on here, but I think it can't just
be the fact that Dad just loves frogs and loves
(04:00):
frogs more than he loves his daughter. Um. But at
any rate, this is the scenario we find ourselves in. Okay,
So what happens? Well, that night, the snake arrives, but
arrives in human form and tries to claim his bride.
And so Dad at this point has not even warned
his daughter about what he agreed to. Uh, so he's
(04:22):
he's able to buy a little time. He's like, look, look,
just come back in a few days, and the snake agrees.
So Dad has a little opportunity here to talk with
his daughter. He tells her what has happened, and she
is rightfully horrified. She hides away in her room and
she prays to the gods for delivery from this, uh,
this snaky fate, and the gods do not answer her
(04:42):
prayers because they're too busy putting crabs in the sky. Perhaps, yeah,
it doesn't say that the gods are are listening to her.
And meanwhile, you know the the the two days pass
and here comes the snake again, only this time the
snake has come in its serpentine for warm. It's an
animal form. It enters her room, and just when it
(05:04):
seems that she is completely abandoned to this fate, a
thousand crabs burst through the door and consume the snake,
just you know, completely deflesh it. A thousand crabs. And
so I guess the idea is like this is that
that she spared the crab earlier, and so she had
she had a friend in the crabs, And or you
(05:24):
could also look at it like the gods did actually
reward her. They were listening and they allowed all these
crab saviors to come and yeah and yeah, save her
from this snake and she marries the swarm of crabs.
I don't know, maybe, but but I love this because
it's also like, oh man, this is something you could have,
like a swarm of crabs tearing tearing an enemy apart
(05:46):
like that that should be in a film somewhere somehow,
this whole thing could be adapted into some sort of
like a weird horror tale. Yeah, crabs are not usually
the hero of a story. M Yeah, this this is
maybe the only one I've really been able to find
so far. But hey, if you know some good crab
hero stories out there, right in, because we'd love to
(06:08):
hear from you, because yeah, generally it seems like crabs
are going to be a minor character. Uh. You know,
let's think of Disney's a Little Mermaid, right. The crab
is just there to be a friend to arial the Mermaid. Uh.
I guess maybe he comes through a time or two,
but he's he's not the focus. He's not the he's
not the big central hero. But you know, I think
it's a kind of mechanically intuitive pairing to have snakes
(06:31):
and crabs together in a tale like this. Yeah, it
does seem like it's something that storytellers around the world
have come back to a few times. Um For instance,
there's this crab snake duology in the Aesop fable The
Snake and the Crab. Also, speaking of Disney movies, it
factors into Disney's The Sword in the Stone, which is
(06:54):
a King Arthur movie that I imagine a number of
you have seen and they're familiar with. It's an otherwise,
in my opinion, it's it's kind of a boring film.
It doesn't have a lot going on, except it has
this fabulous wizard battle between Merlin and this this evil
witch who I think was created for the Like, it's
not Morgana or anything. It's just it's just this witch
(07:16):
that he battles, Mab I think her name is Mim Mim. Yeah,
I think you think you're right. So anyway, it's a
battle between between two magic users and the whole The
rules of the battle are that they have to fight
each other. Uh. No one can turn invisible. You can
only transform into real world animals, not in to fantasy
(07:37):
animals and we're going to see who who winds up
on top. So it's a fabulous sequence where they jump
in and out of various animal forms and there, and
you know, generally trying to counter each other. And in
this it actually reminds me a lot of of of
another of a Japanese story about foxes that are engaging
in a similar competition, magical foxes who are transforming themselves
(07:59):
into different forms, and like one transforms into this and
the other transforms into something to sort of uh counter that,
and it just keeps going. And in this case, one
of them transforms into a snake and the other transforms
into a crab in order to of course clip that
snake in half if it can. Yeah, this comes back
to that mechanically intuitive pairing I was talking about where
(08:21):
I think people just have a natural tendency that goes
like this. So first step you see a thing that
is longer than it is wide, and then the second
step you automatically think about cutting or snipping it cross wise.
So snakes are naturally long and crabs have biological scissors
on their legs. Yes, um I also, yeah, Ni Nim
(08:41):
is great in this, but also I have to say
that Merlin has a wonderful animated mustache as long as
we're we're focusing on November mustaches here, And it makes sense,
right because we think of the like the mouth parts
of a crab, it's easy to to imply some sort
of a mustache going on there as well. Oh yeah,
it fits right in there. Now I want to say
(09:02):
something else here. I thought that this is worth noting
about the crab, the crab form, and about how the
crab is just ultimately this winning design. In fact, it's
such a winning design that, according to a two thousand
twenty one Harvard University study, the crab like body plan
evolved at least five times independently in both true crabs
and false crabs. So that's at least five cases of carcinization. Uh.
(09:26):
This is a term that was coined by evolutionary biologist l. A.
Bora Dale in nineteen sixteen. And on top of this,
the Harvard study points out that the crab body has
been lost at least seven times, so this would be
a process that they refer to as d carcinization. So, um,
I love this idea. I mean this kind of falls
(09:47):
into I think a popular meme about everything becoming crabs,
about how, given enough time, the crab form will be
the form of everything because it just works so exceedingly well. Now,
I do enjoy that meme. I guess technically, if we
want to be pedantic, it's about certain types of arthropods,
like you've already got certain a certain body plan to
start with, and if you're starting their things that are like,
(10:11):
you know, lobster ish or something in one way or
another often are shaped by their environment to become more
crab like. But yeah, yeah, thumbs up to the meme.
So the first crab I thought we might talk about
here today, uh sometimes referred to as the Yeti crab
or the hof crab. It's it's actual name is perhaps
(10:32):
a better suited for this interesting creature. Now, there are
a few different varieties, but the one of the first
that was really discovered that really set the trend is
Kiwa Hersuta. Kiwa is the name of the Maori sea god,
and then Hersuita is Latin for Harry. So Kiwa Hersuta
was discovered by a team from the Monterey Bay Aquarium
(10:52):
in two thousands six along the Pacific Antarctic Ridge south
of Easter island and it is a is a wonderful
looking creature, this pale, hairy looking crab, kind of elongated looking.
I would say, it looks a little bit like, you know,
some sort of a lobster perhaps, but it has no
eyes and it lives on hydrothermal vents. So this discovery
(11:13):
gave us not only a new species, but a new genus,
that Keywa genus. And there are other Cua crabs that
have popped up, including Kiwa ty lerry found off the
Southern found in the Southern Ocean off of Antarctica. And
this species is probably my favorite, as in my opinion,
it's a little more cute looking, it's less elongated, and
(11:34):
it's more it's more plump. It looks I don't know,
it just looks like like like it it belongs in
a cartoon, you know, yes, And it's a great example
of the kinds of things we were just talking about,
with these sort of converging forms of different types of
of marine arthropods. Because technically the Kywa genus are not
true crabs. I think they are a type of lobster
(11:57):
or lobster related organism. But they're they're super cool. I
mean they're also focusing just on Tylery here it has
a tiny habitat, a mere thermal envelope of a few
square meters deep along the East Scotia Ridge. Um, it's
here that they live by these black smokers. These are vents,
(12:18):
These a chimney like vents that spew dark water that
reaches temperatures of roughly seven degrees fahrenheit or three degrees celsius.
They live in heaps here, sometimes like six thousand crabs
per square meter, and they're cramped in here because outside
of this narrow proximity to the Black Smokers, the ocean
is extremely cold. Uh. So they're they're this fascinating example
(12:42):
of extremophile life suspended between boiling eruptions and chilling darkness.
Like this is the niche that they've carved out for themselves.
It's also interesting to imagine how they would spread between
one vent to another. You know that you almost have
to imagine their lifestyle is like a uh you know,
living on these tiny islands in a way. Yeah yeah,
(13:06):
so yeah, so they're on these little little islands and
uh and they're they're jocking position here. So you tend
to find like the older bigger crabs are are are
towards the center, towards the heat, and the adolescents are
having to to scramble for position on the outside. Meanwhile,
the hot, sulfur rich zone is is likely too much
(13:26):
for their eggs, so the females seem to have to
crawl off into the colder, darker waters to brood and
they likely die there. They likely just don't have the energy.
They spend all their energy going out to do that
and they can't make it back. But the females. Then
this releases a vast quantity of larvae into the water
column and some of these end up finding distant vents,
(13:47):
others returning to their own vent um. So you have
this is how we end up with with with with
the larvae from from a particular hydrothermal vent location potentially
ending up at other vents. Yeah, like a lot of
organisms in the ocean, they've got this sort of broadcasting
method of reproduction that allows allows uh the organisms to
(14:09):
spread in their in their larval forms. Yeah. I was
reading a great article about this in on the BBC
website by Jonathan Amos wrote about them in two thousand
eighteen and points out the first of all the last
common ancestor of all these various YETI crabs, probably live
thirty to forty million years ago in the Eastern Pacific.
And so what we have here are these different far
(14:29):
flung ancestors due to the successful colonization of hydrothermal vents
by dispersed larvae UM and so the other. Then the
crazy thing about all this too is once they have
found of a place to thrive, that doesn't mean that
this is a forever home um. In Amos's words, these
various events quote switch on and off through time. So
(14:51):
event that has this thriving population of of of Yetti
crabs around it may just suddenly turn off, and then
everything around that just eyes in the cold um. And
then it may turn back on later uh, and then
it's a place that the larvae can can can can
arrive at and life can sort of begin again until
such time as it just turns off. Returning to the
(15:13):
island analogy, you have to imagine like a small island
that has a thriving ecosystem on it, and then suddenly
it just gets like a dome clamped over it that
turns it into a sub zero freezer. And then at
some point, maybe the dome is suddenly lifted and it's
exposed to the sun again. Yeah. Yeah, and so this
is why any given species of yeti crab has to
(15:35):
ultimately maintain multiple footholds at different events to survive. But
it also drives home the delicate how just how delicate
these event environments are, because um, if human activity wipes out,
you know, potentially, just like it seems like just one
or two of these vent habitats, they could potentially limit
a given species holdings to an unsustainable level. Um. I
(15:58):
don't know that researchers have really worked out. I mean
we we I don't think we know enough about like
you know, all the different places that they live. But yeah,
it's it. Basically, the idea is we we we don't
know just how delicate the situation is. If they're depending
on vents that may again turn off and back on
again at any given moment, they have to have a
foothole in a certain number, And if you start digging
(16:20):
into that number through deep sea mining or some other
human venture, then yeah, you potentially put them in in
an unsustainable place. Won't someone think of the dear crustaceans,
I mean, they are so cute. I mean it is uh,
probably easier than than with a lot of Arthur pods
in the ocean. Degenerate sympathy for them because they look
(16:40):
kind of like, yeah, these pale, fuzzy ticks. Uh, that
doesn't really folks sympathy, does it. But they yeah, they're
they're like plump and cute and I don't know they're good. Well. Also, Tyleria,
especially if you look at a picture of them from
a from above, it also kind of looked with the
pale colorization, it looks like a human skull from above
there's a human skull with skull cover colored legs and
(17:03):
claws coming out of it, which again doesn't sound very cute,
I guess, but um, but but it makes it makes
it a very interesting creature to look at. Now, I
should again stressed that we have different varieties and they
have some different um different features. For instance, tileery have
special spikes for scaling up those chimneys of the black smokers. Meanwhile,
(17:23):
there's a species found near Costa Rica which is Kiwa
pura vita, which doesn't have claws at all. Um. So
you have the have the different varieties, but what they
seem to all have in common is their namesake hair,
which is in here at all but set which they
use to collect bacteria growing around the hydrothermal vents and
also to grow it within these uh what if it's
(17:46):
sometimes referred to as gardens on their bodies, and then
they use their delicate mouthparts to scoop up and consume
the bacteria. So they are you know, they're they're walking
around growing their own food, collecting their own food and
then growing it on their own body. It's pretty great.
Thank thank thank well. This actually connects directly to a
(18:09):
couple more examples I wanted to talk about. So the
first one is connected by the idea of these deep
sea dwelling uh crustaceans that can be found around hydrothermal vents.
So I came across another report of interesting crab feeding behavior.
This this was from a short article and New Scientists
by Sam Wong, and the subject of this uh this
(18:32):
right up was video footage that had been captured by
a robotic deep submersible that was based off of the
Schmidt Ocean Institute's ship, the foul Core, and it had
been exploring life around deep hydrothermal vents in the Pacific
at a depth of thirty meters so way way down.
This was in the Mariana region. Well, I have to
(18:54):
slow down there. That it was called the foul Core.
So it was named for the Wish Dragon and the
Never Ending Story. I don't know what's awesome it so well, yeah,
I don't know this fal Core in the Never Earning
Story named after something else or is that original to
the book? I don't know offhand, so I cannot answer
your question. But that is its name, all right? Or
are you gonna apply to set sail on the Falcore? Now? No,
(19:17):
probably not, but I but I applaud the naming, uh
either way. So anyway, the submersible based off of this
ship was um capturing footage of crabs that were that
were around these hydrothermal hotspots, and this particular species was
known as austin O Greya Williams c. Apparently, not a
(19:38):
whole lot is known about them, but they inhabit these hotspots,
and like many other deep sea creatures, they tend to
be pale and lacking eyes and so as to the
diet of these crabs, they have been observed eating some
regular things like snails and algae, but they have also
been observed engaging in brew rutle cannibalism. You can find
(20:02):
some video footage of this. Uh. It's it's of a
particularly frenzied quality. It's just sort of like a big
murder puddle of pale crabs ripping legs and claws off
and and running away with them. Uh and and and
of course in addition to eating other things in their environment.
But on this expedition, footage was captured of these crabs
(20:23):
doing something a little gentler. They were appearing to groom
one another, eating bacteria off of the shells of con specifics.
So for example, you can see one crab going up
to another crab's leg and just sort of picking at it,
just picking it, not pulling the leg off and running
away with it, as they might be wont to do
(20:43):
in another situation, but just sort of like grazing along
the outside of the leg, getting some of this, uh,
this bacterial matting off of the surface of the of
the exoskeleton. And this is really interesting behavior. It makes
me wonder, like, what does this indicate about the nature
of the crab? Is it possible this could have some
(21:06):
kind of social role within crab society? Like the social
grooming behaviors of primates. I mean, on one hand, that
seems kind of unlikely because these are you know, these
are crabs. They're not they're not social mammals, um, you know.
So it could just be that bacteria is delicious and
here are some right now on on my on this
neighbor's leg. But I guess we don't know that this
(21:27):
kind of thing. I'd be interested to see more research about,
like could there be a role for some type of
social grooming within these within these deep see Arthur pod communities. Interesting. Interesting,
Now I had in the background here, Joe, I had
to do some quick research. And first of all, I
can confirm that the RV Falcore is in fact named
(21:49):
after the Wish dragon in The never Ending Story. Um.
It was. It was originally called the Cea Falcon, but
then it was retrofitted um later um and I believe
two thousand nine or so, and then it was renamed
the foul Core. Now the name Foulcore. Incidentally, Falcore is
the English uh name for the Wish dragon in the
(22:12):
English translation of Michael Linda's The Never Ending Story. In
the German the name is fukor fuc Hu. Are derived
from the Japanese term for lucky dragon fukur you uh
if I'm saying that correctly, And apparently it was changed
in the English translation because, um, the name future sounds
(22:33):
too much like an English language swear word. Okay, well,
I I feel very educated now. Um the way, did
they change the name of the type of dragon in
the movie because I remembered it from the movie as
being a luck dragon? Is it a wish dragon? In
the book? I might have accidentally said wish dragon just now,
but he is. He is a luck dragon. Wish dragon
(22:56):
is is a is a different film that I've also
watched recently. We watched all the dragon films. Okay, we'll
steady sailing to the falcore. But let's get back to
the world of crabs. What else do crabs eat? Okay, well,
so we talked about them growing bacteria on themselves and
eating it off of themselves, and then in some cases
(23:16):
performing grooming like behaviors where they graze bacteria off of
each other. But I want to move on to another
parallel finding. So okay, if you are even the slightest
bit crab curious, you probably know a bit about the
type of crabs known as spider crabs. This involves many
different species, all belonging to the super family known as
Majoi data. They're called spider crabs I think because their
(23:40):
legs can get very long and spind lee, so in
some cases they actually do look like spiders. One of
these animals, maybe the most remarkable spider crab is the
Japanese spider crab or macro chira camp Ferry, which is
the largest extant arthropod in the world. So this is
an ocean dwelling crab that still exists today. It's not
(24:01):
some you know, devonian, your yptorid, giant sea scorpion or something.
You can find these out in the ocean still, and
the largest one on record had a leg span of
around three point eight meters or more than twelve feet,
and it weighed something like forty something pounds. So these
things are enormous. They're mostly legs, so you know, they're
(24:22):
not like a solid mass that big, but if they
spread their legs out, it is it is bigger than
human body. Yeah, you can often find spider crabs at
at aquariums, and they always need to look at I mean,
they don't do much they're they're they're they're not really
action packed, but they're very impressive specimens. But there's actually
another interesting thing about this superfamily, the Majoidea. About three
(24:45):
quarters of the species in the superfamily are examples of
what is known as decorator crabs. Decorator crabs are animals
that live in symbiotic relationships with many different kinds of
sessile organis sums by attaching those organisms to their exoskeletons. Rob,
(25:05):
I've got some images for you to look at. Uh.
There are many different kinds that live in relationships with
many different kinds of other species, but generally a decorator
crab wears other plants or animals as clothing on the
outside of its shell as a form of camouflage to
blend into its surroundings. And it does this by hooking
(25:26):
these other organisms onto little bristles on its exoskeleton called
ct S E T A E, which I've seen compared
to velcrow, So this might be a sort of natural
precedent for for velcrow technology. There are lots of different
kinds of other creatures that get roped into this. Some
particular species of decorator crabs, uh, prefer algae, some prefer sponges,
(25:50):
some look for certain bryozoans, and some like anemonies that
can sting. Oh yeah, I think. Yeah. There's been some
some interesting studies we've probably talked about in the show
before about these uh, these anemone wielding crabs. Uh. And
then what what? They usually have one on each claw
and then if one gets taken away, they can care
one in half to have two again that sort of thing.
(26:12):
Were these the boxer crabs? Yeah, I think so. Well, yeah,
so that example in particular of anemon ees that can
give you a hint that sometimes these decorations on the
outside of the shell do more than simply camouflage the
animal as it hides among the rocks and the other
flora and fauna populating the sea floor. Some of these
decorator crabs select organisms that play a specific defensive role.
(26:37):
So I was looking at a table of findings of
this sword published in a book called Animal Camouflage, Mechanisms
and Function edited by Martin Stevens and Semi Mirlita. And
this was from Cambridge University Press in two thousand eleven,
and it lists a bunch of different examples of different
types of majoid crabs along with research identifying their preferred
(27:01):
decorations and possible reasons for that preference. So, for example,
there is a type of crab known as the innocous
Philangium or the leeches spider crab. It appears to prefer
a type of brown algae known as Dictyota dick atoma
for the parts of its body most exposed to predators.
And it turns out that this species of algae is
(27:24):
not only good camouflage, it is chemically noxious, So it
hides that this crab hides the vulnerable parts of its
body behind something that predators would probably find disgusting or
even poisonous. Uh. Maybe, like if you were trying to,
you know, protect yourself from tigers by covering your back
in bottles of bleach. You know, a tiger gets in
(27:45):
there and starts biting it's it's not gonna want any
of that. Also along these lines, there's an Atlantic spider
crab called Stino c o ops for cot Us that
preferentially attaches a species of stinging anemony to its carapace.
And in both cases, these decorations would appear to provide
additional defenses. Beyond just masking the body in the environment.
(28:05):
But the crab from this list that I wanted to
focus on has a different relationship with its preferred decoration organism.
It likes to eat its own camouflage. So the animal
in question is known as noo Mithrax ursus, or the
hairy seaweed crab. I think the Latin name of its
of its species ursus, implies that it's also known as
(28:26):
the bear seaweed crab or sign bear. And folks, I
just want to say, off the bat, this is a
beautiful crab. In some cases it looks like a cartoon
animation of a crab being electrocuted. It's got like animated
electricity lines all around it. Also sometimes it looks like
a burst of fireworks from hell. It is just a
(28:49):
gorgeous Arthur pod. And I can definitely see where the
name comes in because it it is it looks like
it's furry like the bear. You know, yeah, totally um So,
it has some natural hairs that that stick out from
its exo skeleton. But it's also generally well actually not
in all environments, but in some environments it covers itself
in uh in. In these decorations that give it this
(29:11):
additionally hairy look. So according to an entry, I was
reading about it from the Museum's Victoria database the Australian
Um Natural History Museums. UH. These are found in rocky
shores and reefs around New Zealand and Southeastern Australia. And
I was further reading about this this species in a
(29:32):
in a research paper published in the New Zealand Journal
of Marine and Freshwater Research in nineteen ninety four by
Chris Woods and Colin McClay called masking and Ingestion Preferences
of the spider crab not a mythrax Ursus. And what
the researchers here say is that in laboratory tests, specimens
of this crab not a mithrax Ursus were found to
(29:54):
have preferences when it came to which organisms they would
mask with. So it wasn't just any algae. There are
certain kinds of algae they like to put on their shells,
and specifically it was types of branched algae like hallop
terrorists specific era and Corallina office analis. And I actually
(30:14):
just want to read in full a part from the
introductory section of this paper that describes the process of
attaching pieces of algae to the body because I found
it really fascinating to picture this routine as the crab
does it. Uh and so too. As a note to
help understand what I'm about to read here, the words
chili and chella pads refer to the claws. The chili
(30:36):
are the claws and the chili pads are the claw legs.
Pad isn't foot, so the authors write quote. The masking
behavior of in Ursus begins with the selection of a
clump of algae. The crab then selects a single piece
of alga, using the chili in a cella over cella
technique to correctly measure the piece of algae to the
(30:58):
required size, So the measuring it out using their claws
as a as a as a ruler. Basically, this piece
of alga is then snipped off using the cheli and
transferred to the mouth parts, where the cut end is
roughened and trimmed of any projections, while the uncut end
is held by both chelipeds. Okay, so holding it in
(31:19):
the claws and then chewing on the snipped end, putting
it in the mouth parts to chew on it. Then
once you've chewed up the cut end good uh quote.
One cheli pad is then used to transfer the piece
to a part of the body. Attachment is accomplished by
rubbing it against the hooked set so that the cut
end becomes entrapped by the set. If the algal piece
(31:40):
does not attach, it first is transferred back to the
mouth parts to be manipulated, and then taken back to
the side of attachment and rubbed against the hook set
until it attaches. If the piece of alga fails to
attach after a number of attempts, it is discarded and
a new piece is selected. I don't know why, but
I found this kind of surprising. Something seemed kind of
comple x and and and crafty about this process. Yeah,
(32:04):
I mean it. It's it's a process that may seem,
you know, out of beyond the abilities of what we
might might generally attribute to a crab. But then again,
we think about the way they eat, which we discussed
in the first episode, and it does sound like a
natural extension of that, Like this is an animal that
is very that excels at taking things apart um uh
(32:26):
you know I usually so it can fit those things
in its mouth, uh, and can consume it but this
is kind of a specialized version of the same thing,
manipulating living things um and then using the pieces of
that thing that you have manipulated. It ends up being
this kind of kind of like biomancy that the crab practices. Yeah, totally.
(32:48):
I just love that detail about it chewing the snipped
end of the alga in order to roughen it so
that it attaches to the vel crow on its back. Yeah. Now,
another interesting fact this paper mentions is that there is
a lot of turnover in the crabs algae mask. Apparently
not a Mithrax ursus replaces a good ten to twenty
of its algae cover every twenty four hours. That would mean,
(33:10):
you know, every roughly five to ten days, it's got
a new coat of algae on it. And apparently decorator
crabs that use algae in particular can be very strategic
about its benefits as camouflage. For example, previous research, so
not this study, but other studies they cite, had found
in some decorator species that when you put a crab
(33:32):
in a tank where it is surrounded by algae that
doesn't match the color of the algae on its current mask,
it will basically strip itself of the old algae and
redecorate itself with the new algae to match its environment.
And also research has shown that when given the option,
crabs will tend to stay hidden within masses of algae
(33:54):
that match the color of their existing mask. So these
crabs can distinguish between different types of masking materials and
they can make calls about masking and hiding behaviors to
maximize the camouflage effects. Wow, that's really it's really impressive. Yeah,
it's it. It goes beyond just this near sort of
automatic behavior that's taking place with anything that it happens
(34:18):
to come across, right, So, yeah, it's not just sort
of like rubbing up against a bunch of algae and
getting it stuck on there. It's picking the algae that
will that will do the best job of camouflage. But
the researchers in this study found a different kind of
discrimination in the selection of the masking material when it
came to Noto Mithrax ursus. They found that the algae
(34:40):
species the crabs preferred to mask with were the same
ones they preferred to eat. So if you make like
a ranked list of all of the algae that the
crab will go to first to eat which ones doesn't
like to consume the most That is going to be
the same as the list that it will choose to
put on its carapace and down its legs. So in
(35:02):
a way, here it looks like the camouflage is doubling
as food storage. This crab is hiding behind a mask
of its own lunch, so the algae on its back
will help it blend in with its environment, make it
look like a bunch of seaweed rather than a crab,
so predators are you know, are less likely to spot it.
(35:23):
But then also it can eat that seaweed. It can
eat that algae if it gets hungry. It's like if
we were to imagine a like an army sniper in
one of those gilly suits, but they insisted on only
camouflaging themselves with their favorite leafy greens so that they
could snack on it whilst while stalking, you know, and
(35:43):
and and waiting on their their target to appear. This
gilly suit is a super food kale only kale gilly suit.
I love it, though I guess it does make me
wonder maybe there is an answer to this. I'm not sure,
but it makes me wonder which way the adaptation goes, Like,
how how did it end up matching the food preferences
and the masking preferences? Um? So, like, was it because
(36:05):
a certain type of algae was the best, you know,
provided the best camouflage cover, the animal evolved to prefer
eating that kind or was it the kind that's most
delicious and nutritious it evolves to prefer for masking. Yeah,
that's a great question. Yeah, the crabs are silent on
the matter than all Right, up next we have this
(36:33):
will be a shorter little section here, but this is
something you you you pinpointed and then I followed up
by by looking at a source on it. But this
is the idea of crabs eating. This is so much
crabs eating something remarkably different, but crabs doing it in
a way we didn't expect. And that's crabs eating quote
(36:55):
unquote eating through their gills. Yeah, this is interesting, so
circumventing the look at mouth parts that you don't even
have to raise a jaw leg for this meal. Right,
So this concerns the invasive or at least invasive in
um uh North America and I believe in Africa as well. Uh.
The the invasive green shore crab, which we've discussed on
(37:16):
the show before. I believe in their native European waters
they are sometimes harvested for food, and there have been
efforts in North America, where it is certainly invasive, to
encourage its use in cooking. You know, what are some
culinary uses for this, and I think there have been
some some ideas of using it as like a uh
you know, like like a soup base and so forth. Um,
(37:37):
that's the same tactic you see with like invasive lion fish,
hinging on the fact that if you really want humans
to make a species disappear, make them desire that species
for some reason or another, such as making it an
ideal main course at a dinner. Sure. I think we've
actually covered the green shore crabs in a different capacity
on the show before. I don't remember what it was, though,
(37:58):
so as point it out in a two thousand seventeen
study from the University of Alberta, the green crabs are
pretty snazzy consumers in their own right because they can
again quote unquote eat by absorbing nutrients, specifically the amino
acid um loose sign across their gills. And this was
(38:19):
the first demonstration of crustaceans being able to do this.
Now that the crabs are notoriously hardy, as you often
see with an invasive species, um, so their bility disability
might enable them to survive long periods between meals. So
I don't have anything to eat, but I can absorb
some some necessary amino acids, or it might help them
(38:39):
cope with changes in salinity. So offsetting salinity changes via
the amino acids that they can absorb just straight through
their gills. Okay, so they would not be fully like
sucking in chunks of food through their gills and eating
like that. It's it's specifically getting these particular amino acids,
these particular nutrients out of the water around them as
(39:01):
they breathe. Yeah, so you know that's again whine we
put eat in quotation marks here. I guess it's kind
of like our humans eating when we absorb vitamin D
via sunlight, that sort of thing. Are we are we
eating when we get a you know, some sort of
a vitamin injection or something. Yes, Okay, I've got something
(39:22):
I was wondering about. Rob You may have seen it's
a very popular genre of internet video, uh feeding crabs
human food you know, I don't really think I've seen
any of these. What kind of foods are they feeding
them in these videos? Oh? Everything I've seen. I think
I've seen crabs eating pizza. I've seen crabs eating you know,
fruits and vegetables and chips and all the giving crab
(39:46):
derito is probably I don't remember all the specifics, but
you know, I've seen a good bit of this in
my day. Clearly, it's funny to look at, you know, crabs,
the kind of it thinks it's people sort of thing,
right exactly, A crab eating a rito is inherently comedic.
I don't know if it's good for the crab though,
then again, lots of crabs or scavengers, you know, they'll
eat what what they can get. Um. So, so I
(40:09):
guess I'm not too worried about the crabs. But but
but I just wondered, is there anything interesting to cover
about the phenomenon of crabs eating human food? All right,
so we cannot speak for all crabs. We will not
speak for all crabs. But one fun place, uh to
look for some answers that I thought would be to
(40:30):
look to the realm of hermit crabs as pets. Joe,
did you ever have a hermit crab as a pet?
I did not, did you. I've always wanted one, but um,
it's never been permitted. I'm always like that looks that
could be a great pet, and and and whoever is
in my life is always like, I don't know if
you need that, and they're they're probably correct. So you
(40:51):
mean your family now is preventing you from getting hermit crabs, right?
I think it's the Yeah. I think the argument is
a hermit crab is either too much pet or not
enough pet. So it's either a situation where like, uh,
you really, you know, ask yourself, do we have space
and time for this creature to live in our life
as well? Or it's a question of is there something
(41:14):
more exciting we could have, like a lizard, And that's like,
that's where we are now. We have a we have
a leopard gecko. We skipped over hermit crab and went
straight to leopard gecko. This is a vertebrate household, so
to be clear, there are more than one thousand hermit
crab species and you can roughly divide them all up
into marine hermit crabs and terrestrial hermit crabs. Uh, so
(41:34):
you're you know, you're your sea dwellers and then your
land dwellers. And there are a few different species that
are popular pets from either category, but the ones most
likely to encounter human food are of course those terrestrial crabs.
So I thought I might look at some terrestrial hermit
crab feeding guides for some ideas. Okay, so I went
to the spruce pets. This is I think it's from
(41:55):
the same people who like the sprucey heats, uh, And
they point out that commerce hermit crab diets are probably
the best way to go if you're feeding a hermit crab,
because these are balanced and they contain everything that they
might need because in general, you know, matching up with
pretty much everything we've been talking about here, they're going
to have a very diet their opportunistic land roving omnivore,
(42:16):
so they're gonna eat a little bit of this, a
little bit of that in the natural world, and you
need a food source that reflects that they're on the
seafood diet. I seafood, I eats it pretty much. Yeah,
So they recommend I'm going to roll through a lot
of foods here. They recommend such fresh foods as mango, papaya,
coconut fresh or dried. And I have to add that
(42:37):
I can certainly back up the coconut suggestion because um,
I got to watch a whole bunch of hermit crabs
go absolutely crazy over a busted open coconut once, and
it was it was amazing. It was a feeding frenzy.
Where were you seeing the wild hermit crabs? I believe
this was in Belize if memory serves. Oh, okay, all right,
But in addition to this, apples, apple sauce, bananas, grapes, pineapple, strawberries, melons, carrots, spinach, watercress,
(43:04):
leafy green lettuces, but not iceberg lettuce because you know
the the nutrient issue there. Uh, Broccoli, grass leaves, strips
of deciduous tree bark, unsalted nuts, occasional peanut, butter, raisins,
dried seaweed, crackers, unsweetened cereals, plain rice cakes, plain popcorn
(43:26):
on occasion, freeze, dried shrimp, freeze dried plankton, brian shrimp, fish,
food flakes, and much more. Okay, so it looks to
me like this, Uh, this list of suggestions from this
website is suggesting a wide range of different kinds of foods,
but seems to be avoiding things that have added sugar
(43:47):
or salt. Yeah. They point out that the crabs may
seem very interested in salty and sweet snacks like chips
and sweet breakfast cereals, but these are to be avoided.
They say also stay away from dairy products, which makes
sense when when when would have a crab get a
dairy product in the natural world. Um. And they say
that the hermes are generally gonna be game for fresh
(44:08):
or dried fruits of any kind, but some experts advise
against highly acidic or citrus foods, so like maybe don't
give them a limon or a tomato. Also, starch veggies
like potatoes are to be avoided um as well as
again low nutrient iceberg lettuce. What I all this hating
on iceberg lettuce? I love iceberg lettuce. I'm gonna go
(44:28):
out on a limb right here. I'm gonna say iceberg
lettuce is awesome. I mean it, iceberg lettuce can be awesome,
But the question is what are you getting out of it? Well,
I don't know what you're getting out of it nutrient wise,
but it's delicious, crunchy crunchy goodness. Alright, fair, fair enough,
just keep it away from the hermit crabs. Um. Now, also,
hermit crabs require calcium, So remember that bone gnawing we
(44:50):
mentioned from the last episode involving other crabs kind of
plays into into this scenario. Uh, calcium edition probably not
gonna come as a surprise to many pet owners out there.
I know. With our leopard gecko, we have to we
have to shake its crickets up in a bag with
a calcium powder to ensure there's getting enough calcium, and
then also leave some calcium out for it in a
little tiny dish. Um. But with crabs you can end
(45:14):
up using reptile ready calcium supplements like this. But also
you might end up using something like crushed oyster shells
or cuttle bone as something that they can use to
get their their calcium. Oh yeah, okay, So tying it
back to the last episode, I was just remembering the
suggestion this was not proven, but it was it was
hypothesized that maybe one reason duck built dinosaurs had been
(45:36):
eating a bunch of crustaceans that might have been crabs
or some of their you know, related crustaceans that have
these these hard shells. Was that they were looking for
certain nutrients types of protein or specifically calcium as part
of their breeding and reproduction cycle. Yeah. Now one more,
one more note from this spruce article because it's just
(45:56):
it's so crab. I love it. They say, quote hermit
crabs are able to find their food in two ways,
by smelling the food and by seeing other hermit crabs
eating hermit crab dietary peer pressure. Yeah, so they might
be like I detect food over there, or it's like
that hermit crabs eating something I'm in, I'm gonna go.
(46:18):
I'm gonna go try and steal some of that. All
the hermit crabs like Billy gets to eat iceberg lettus
Billy gets to eat pizza. Yeah. But obviously, I, like
I said, I do not have a hermit of a
pet hermit crab. I've never had one. I've just gotten
to observe some in the wild and you know, look
at them in pet stores. So, if there are any
hermit crab enthusiasts out there and you have particular thoughts
(46:38):
on this, if you can tell us, uh, you know
what foods your hermit crab prefers the most, which ones
you you like to give them definitely right in and
let us know, I'd I'd love to hear from that. Really,
anybody out there with with crab expertise or crabs pertise,
uh you know, right in? Have you ever had part
of your body eaten by hermit crabs? What was that? Like?
(47:01):
Hermit crabs do they just have a lot of character?
I love I love watching them. Yeah. Actually I recall
one Nature documentary segment I honestly don't remember what it
was from, but I think it was something narrated by
by Attenborough. Um. But it was a segment that was
showing hermit crabs forming a chain of shell trading, so
like they were all trying to trade shells to get
(47:25):
a bigger shell, and they formed up in a line
essentially to each switch into the next one's shell. Yeah,
there have been essentially like biology economics articles that have
looked at this, like how do they go about, um,
you know, trading up on their their shell size? And
then you know, because if one leaves its shell for
a bigger shell, then that opens up a shell for
(47:46):
another growing hermit crab to take advantage of it. It's
it's really fun. So the adaptation there I guess would
have to involve the hermit crab observing when a bigger
hermit crab is likely to be leaving its shell for
for a bigger one. So I yeah, that would take
some kind of social observance, kind of like what you're
talking about with the hermit crabs watching other hermit crabs eat. Yeah,
(48:09):
I mean I think also they're they're all about stealing
as well. If so, it's it's a it's a crab
kind of a crabby crab world. But who comes up
with these rules? You can steal somebody else's shell, but
you can't eat iceberg let us. Now, they will eat
the iceberg. It's not that they don't want it, I think.
I think the idea is like, they will eat it,
(48:30):
but it's just they deserve better. Okay, coming up soon,
we're gonna do a whole episode on iceberg let us.
It'll be about how iceberg let us is the king
of foods. It's amazing. I know that what iceberg let
us must not occur in nature. Whoever created the strain
of vegetable is really deserves great credit. All right, Well
(48:51):
we're gonna go ahead and close it out there. But yeah,
again right in. We'd love to hear from you. Let
us know if there are other examples of curious crab
cuisines that that we were not familiar with. It didn't
have time to cover here. We will mention it in
an upcoming listener mail episode. Also, yes, hermit crab owners,
right in and tell us all about your babies. In
(49:12):
the meantime, if you would like to listen to other
episodes of Stuff to Blow Your Mind, you can find
us in the Stuff to Blow Your Mind podcast feed
that it gets found anywhere you get your podcasts. Just
you know, make sure you subscribe and you can get everything,
including our core episodes on Tuesdays and Thursdays, our listener
mail episodes on Mondays are artifact short form episodes on Wednesday,
(49:33):
and then on Friday you get Weird How Cinema. That's
our time to just talk about a strange film of
one sort or another. Huge thanks as always to our
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(50:02):
to Blow your Mind is production of I heart Radio.
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your favorite shows.
Welcome to Stuff to Blow Your Mind, the production of
My Heart Radio. Hey, welcome to Stuff to Blow your Mind.
My name is Robert Lamb and my name is Joe McCormick.
And we're back with part two of the Feast of Crabs.
If you haven't heard part one, you should probably go
(00:23):
back and listen to that one first. But I'm ready
to jump right in. Yeah, we're gonna We're gonna continue
with our exploration of various uh accounts of crabs eating
curious things, eating things in curious ways, and so forth.
This is kind of our big kome of tradition during
the holidays towards the end of the year to dive
(00:45):
into a crab related topic and see what it has
for us. Now, we haven't talked a lot about mythology
and folklore in in our crab journey thus far. And
you know, part of it is when you look around,
crabs often don't have central roles in um in myth cycles.
I mean there, I think there's some exceptions to the rule,
(01:07):
but a lot of times it's stuff like like Hercules
is fighting the hydra and then a crab shows up
and tries to to to nip at his heels and
he dispatches it and goes back to fighting the hydra
that sort of thing. Oh yeah, that sounds it was.
So that's the crab cancer, right that we can the
constellation name from, or that has the same name as
the constellation. I mean, he still gets a constellation out
(01:29):
of the whole affair. But it's you know, it's it's
it can feel a little bit disappointing if you're really
into crab anatomy and into crab monster movies. Um, it
can be a little a little bit of a letdown, like,
come on, you can't Hercules have more of a battle.
Can't he just battle the crab? That sounds fun to me.
Oh wait, I just had to look this up because
(01:50):
I wasn't sure if I was remembering it right. But yeah,
he he gets the constellation basically because Hara hates Heracles
and the crab like bites him on the foot, and
then Heracles kills the crab, and Hera is like, well,
good job biting him on the foot. I'll put you
in the sky forever. The Greek gods. Well, I do
(02:12):
have a fun one that I found though, that I
want to share with everybody. This one I discovered in
the book Japanese Mythology A to Z by Jeremy Roberts.
I looked around to try and find in some other
places as well and didn't off hand. Um, I'm sure
it can be found other places, but this is the
only place I was able to find find it. I'm
going to retell it for you here, but I'll stress
that Jeremy roberts telling of it is is going to
(02:35):
be more dramatic than mine, So definitely go to that
source if you want to see it for yourself. So
that is how it goes down. A young girl, uh
buys a crab from a fisherman in order to save
the crabs life. She's doing you know, that basic thing
that a lot of little kids will do, where they suddenly,
you know, they'll feel sorry for a captive animal or
a food animal and they want to to save it.
(02:57):
And so that's what this girl does. She buys the crab,
lets it go. Meanwhile, her father is in a similar scenario.
He's trying to save a frog from a snake. I'm
not sure why, but he's trying to do this. He's like, no, snake,
you do not get to eat this frog. I'm not
gonna let you do it, and the snake finally is like, okay, look,
(03:18):
I'll spare the frog's life, but you have to let
me marry your daughter, and Dad agrees. So we we
don't know anything about this frog. It's not special, like
it wasn't his brother who got turned into a frog
or something. There has to be more to this story. Um.
You know, I've been reading a lot about various yokai recently,
(03:40):
and you know, with with those Chinese ghost stories, there's
often some hidden meaning. You know, maybe it comes down
to a turn of phrase, you know, something that's not
going to be obvious in a pure English translation, or
it's something metaphorical, etcetera. So I don't know exactly what
is going on here, but I think it can't just
be the fact that Dad just loves frogs and loves
(04:00):
frogs more than he loves his daughter. Um. But at
any rate, this is the scenario we find ourselves in. Okay,
So what happens? Well, that night, the snake arrives, but
arrives in human form and tries to claim his bride.
And so Dad at this point has not even warned
his daughter about what he agreed to. Uh, so he's
(04:22):
he's able to buy a little time. He's like, look, look,
just come back in a few days, and the snake agrees.
So Dad has a little opportunity here to talk with
his daughter. He tells her what has happened, and she
is rightfully horrified. She hides away in her room and
she prays to the gods for delivery from this, uh,
this snaky fate, and the gods do not answer her
(04:42):
prayers because they're too busy putting crabs in the sky. Perhaps, yeah,
it doesn't say that the gods are are listening to her.
And meanwhile, you know the the the two days pass
and here comes the snake again, only this time the
snake has come in its serpentine for warm. It's an
animal form. It enters her room, and just when it
(05:04):
seems that she is completely abandoned to this fate, a
thousand crabs burst through the door and consume the snake,
just you know, completely deflesh it. A thousand crabs. And
so I guess the idea is like this is that
that she spared the crab earlier, and so she had
she had a friend in the crabs, And or you
(05:24):
could also look at it like the gods did actually
reward her. They were listening and they allowed all these
crab saviors to come and yeah and yeah, save her
from this snake and she marries the swarm of crabs.
I don't know, maybe, but but I love this because
it's also like, oh man, this is something you could have,
like a swarm of crabs tearing tearing an enemy apart
(05:46):
like that that should be in a film somewhere somehow,
this whole thing could be adapted into some sort of
like a weird horror tale. Yeah, crabs are not usually
the hero of a story. M Yeah, this this is
maybe the only one I've really been able to find
so far. But hey, if you know some good crab
hero stories out there, right in, because we'd love to
(06:08):
hear from you, because yeah, generally it seems like crabs
are going to be a minor character. Uh. You know,
let's think of Disney's a Little Mermaid, right. The crab
is just there to be a friend to arial the Mermaid. Uh.
I guess maybe he comes through a time or two,
but he's he's not the focus. He's not the he's
not the big central hero. But you know, I think
it's a kind of mechanically intuitive pairing to have snakes
(06:31):
and crabs together in a tale like this. Yeah, it
does seem like it's something that storytellers around the world
have come back to a few times. Um For instance,
there's this crab snake duology in the Aesop fable The
Snake and the Crab. Also, speaking of Disney movies, it
factors into Disney's The Sword in the Stone, which is
(06:54):
a King Arthur movie that I imagine a number of
you have seen and they're familiar with. It's an otherwise,
in my opinion, it's it's kind of a boring film.
It doesn't have a lot going on, except it has
this fabulous wizard battle between Merlin and this this evil
witch who I think was created for the Like, it's
not Morgana or anything. It's just it's just this witch
(07:16):
that he battles, Mab I think her name is Mim Mim. Yeah,
I think you think you're right. So anyway, it's a
battle between between two magic users and the whole The
rules of the battle are that they have to fight
each other. Uh. No one can turn invisible. You can
only transform into real world animals, not in to fantasy
(07:37):
animals and we're going to see who who winds up
on top. So it's a fabulous sequence where they jump
in and out of various animal forms and there, and
you know, generally trying to counter each other. And in
this it actually reminds me a lot of of of
another of a Japanese story about foxes that are engaging
in a similar competition, magical foxes who are transforming themselves
(07:59):
into different forms, and like one transforms into this and
the other transforms into something to sort of uh counter that,
and it just keeps going. And in this case, one
of them transforms into a snake and the other transforms
into a crab in order to of course clip that
snake in half if it can. Yeah, this comes back
to that mechanically intuitive pairing I was talking about where
(08:21):
I think people just have a natural tendency that goes
like this. So first step you see a thing that
is longer than it is wide, and then the second
step you automatically think about cutting or snipping it cross wise.
So snakes are naturally long and crabs have biological scissors
on their legs. Yes, um I also, yeah, Ni Nim
(08:41):
is great in this, but also I have to say
that Merlin has a wonderful animated mustache as long as
we're we're focusing on November mustaches here, And it makes sense,
right because we think of the like the mouth parts
of a crab, it's easy to to imply some sort
of a mustache going on there as well. Oh yeah,
it fits right in there. Now I want to say
(09:02):
something else here. I thought that this is worth noting
about the crab, the crab form, and about how the
crab is just ultimately this winning design. In fact, it's
such a winning design that, according to a two thousand
twenty one Harvard University study, the crab like body plan
evolved at least five times independently in both true crabs
and false crabs. So that's at least five cases of carcinization. Uh.
(09:26):
This is a term that was coined by evolutionary biologist l. A.
Bora Dale in nineteen sixteen. And on top of this,
the Harvard study points out that the crab body has
been lost at least seven times, so this would be
a process that they refer to as d carcinization. So, um,
I love this idea. I mean this kind of falls
(09:47):
into I think a popular meme about everything becoming crabs,
about how, given enough time, the crab form will be
the form of everything because it just works so exceedingly well. Now,
I do enjoy that meme. I guess technically, if we
want to be pedantic, it's about certain types of arthropods,
like you've already got certain a certain body plan to
start with, and if you're starting their things that are like,
(10:11):
you know, lobster ish or something in one way or
another often are shaped by their environment to become more
crab like. But yeah, yeah, thumbs up to the meme.
So the first crab I thought we might talk about
here today, uh sometimes referred to as the Yeti crab
or the hof crab. It's it's actual name is perhaps
(10:32):
a better suited for this interesting creature. Now, there are
a few different varieties, but the one of the first
that was really discovered that really set the trend is
Kiwa Hersuta. Kiwa is the name of the Maori sea god,
and then Hersuita is Latin for Harry. So Kiwa Hersuta
was discovered by a team from the Monterey Bay Aquarium
(10:52):
in two thousands six along the Pacific Antarctic Ridge south
of Easter island and it is a is a wonderful
looking creature, this pale, hairy looking crab, kind of elongated looking.
I would say, it looks a little bit like, you know,
some sort of a lobster perhaps, but it has no
eyes and it lives on hydrothermal vents. So this discovery
(11:13):
gave us not only a new species, but a new genus,
that Keywa genus. And there are other Cua crabs that
have popped up, including Kiwa ty lerry found off the
Southern found in the Southern Ocean off of Antarctica. And
this species is probably my favorite, as in my opinion,
it's a little more cute looking, it's less elongated, and
(11:34):
it's more it's more plump. It looks I don't know,
it just looks like like like it it belongs in
a cartoon, you know, yes, And it's a great example
of the kinds of things we were just talking about,
with these sort of converging forms of different types of
of marine arthropods. Because technically the Kywa genus are not
true crabs. I think they are a type of lobster
(11:57):
or lobster related organism. But they're they're super cool. I
mean they're also focusing just on Tylery here it has
a tiny habitat, a mere thermal envelope of a few
square meters deep along the East Scotia Ridge. Um, it's
here that they live by these black smokers. These are vents,
(12:18):
These a chimney like vents that spew dark water that
reaches temperatures of roughly seven degrees fahrenheit or three degrees celsius.
They live in heaps here, sometimes like six thousand crabs
per square meter, and they're cramped in here because outside
of this narrow proximity to the Black Smokers, the ocean
is extremely cold. Uh. So they're they're this fascinating example
(12:42):
of extremophile life suspended between boiling eruptions and chilling darkness.
Like this is the niche that they've carved out for themselves.
It's also interesting to imagine how they would spread between
one vent to another. You know that you almost have
to imagine their lifestyle is like a uh you know,
living on these tiny islands in a way. Yeah yeah,
(13:06):
so yeah, so they're on these little little islands and
uh and they're they're jocking position here. So you tend
to find like the older bigger crabs are are are
towards the center, towards the heat, and the adolescents are
having to to scramble for position on the outside. Meanwhile,
the hot, sulfur rich zone is is likely too much
(13:26):
for their eggs, so the females seem to have to
crawl off into the colder, darker waters to brood and
they likely die there. They likely just don't have the energy.
They spend all their energy going out to do that
and they can't make it back. But the females. Then
this releases a vast quantity of larvae into the water
column and some of these end up finding distant vents,
(13:47):
others returning to their own vent um. So you have
this is how we end up with with with with
the larvae from from a particular hydrothermal vent location potentially
ending up at other vents. Yeah, like a lot of
organisms in the ocean, they've got this sort of broadcasting
method of reproduction that allows allows uh the organisms to
(14:09):
spread in their in their larval forms. Yeah. I was
reading a great article about this in on the BBC
website by Jonathan Amos wrote about them in two thousand
eighteen and points out the first of all the last
common ancestor of all these various YETI crabs, probably live
thirty to forty million years ago in the Eastern Pacific.
And so what we have here are these different far
(14:29):
flung ancestors due to the successful colonization of hydrothermal vents
by dispersed larvae UM and so the other. Then the
crazy thing about all this too is once they have
found of a place to thrive, that doesn't mean that
this is a forever home um. In Amos's words, these
various events quote switch on and off through time. So
(14:51):
event that has this thriving population of of of Yetti
crabs around it may just suddenly turn off, and then
everything around that just eyes in the cold um. And
then it may turn back on later uh, and then
it's a place that the larvae can can can can
arrive at and life can sort of begin again until
such time as it just turns off. Returning to the
(15:13):
island analogy, you have to imagine like a small island
that has a thriving ecosystem on it, and then suddenly
it just gets like a dome clamped over it that
turns it into a sub zero freezer. And then at
some point, maybe the dome is suddenly lifted and it's
exposed to the sun again. Yeah. Yeah, and so this
is why any given species of yeti crab has to
(15:35):
ultimately maintain multiple footholds at different events to survive. But
it also drives home the delicate how just how delicate
these event environments are, because um, if human activity wipes out,
you know, potentially, just like it seems like just one
or two of these vent habitats, they could potentially limit
a given species holdings to an unsustainable level. Um. I
(15:58):
don't know that researchers have really worked out. I mean
we we I don't think we know enough about like
you know, all the different places that they live. But yeah,
it's it. Basically, the idea is we we we don't
know just how delicate the situation is. If they're depending
on vents that may again turn off and back on
again at any given moment, they have to have a
foothole in a certain number, And if you start digging
(16:20):
into that number through deep sea mining or some other
human venture, then yeah, you potentially put them in in
an unsustainable place. Won't someone think of the dear crustaceans,
I mean, they are so cute. I mean it is uh,
probably easier than than with a lot of Arthur pods
in the ocean. Degenerate sympathy for them because they look
(16:40):
kind of like, yeah, these pale, fuzzy ticks. Uh, that
doesn't really folks sympathy, does it. But they yeah, they're
they're like plump and cute and I don't know they're good. Well. Also, Tyleria,
especially if you look at a picture of them from
a from above, it also kind of looked with the
pale colorization, it looks like a human skull from above
there's a human skull with skull cover colored legs and
(17:03):
claws coming out of it, which again doesn't sound very cute,
I guess, but um, but but it makes it makes
it a very interesting creature to look at. Now, I
should again stressed that we have different varieties and they
have some different um different features. For instance, tileery have
special spikes for scaling up those chimneys of the black smokers. Meanwhile,
(17:23):
there's a species found near Costa Rica which is Kiwa
pura vita, which doesn't have claws at all. Um. So
you have the have the different varieties, but what they
seem to all have in common is their namesake hair,
which is in here at all but set which they
use to collect bacteria growing around the hydrothermal vents and
also to grow it within these uh what if it's
(17:46):
sometimes referred to as gardens on their bodies, and then
they use their delicate mouthparts to scoop up and consume
the bacteria. So they are you know, they're they're walking
around growing their own food, collecting their own food and
then growing it on their own body. It's pretty great.
Thank thank thank well. This actually connects directly to a
(18:09):
couple more examples I wanted to talk about. So the
first one is connected by the idea of these deep
sea dwelling uh crustaceans that can be found around hydrothermal vents.
So I came across another report of interesting crab feeding behavior.
This this was from a short article and New Scientists
by Sam Wong, and the subject of this uh this
(18:32):
right up was video footage that had been captured by
a robotic deep submersible that was based off of the
Schmidt Ocean Institute's ship, the foul Core, and it had
been exploring life around deep hydrothermal vents in the Pacific
at a depth of thirty meters so way way down.
This was in the Mariana region. Well, I have to
(18:54):
slow down there. That it was called the foul Core.
So it was named for the Wish Dragon and the
Never Ending Story. I don't know what's awesome it so well, yeah,
I don't know this fal Core in the Never Earning
Story named after something else or is that original to
the book? I don't know offhand, so I cannot answer
your question. But that is its name, all right? Or
are you gonna apply to set sail on the Falcore? Now? No,
(19:17):
probably not, but I but I applaud the naming, uh
either way. So anyway, the submersible based off of this
ship was um capturing footage of crabs that were that
were around these hydrothermal hotspots, and this particular species was
known as austin O Greya Williams c. Apparently, not a
(19:38):
whole lot is known about them, but they inhabit these hotspots,
and like many other deep sea creatures, they tend to
be pale and lacking eyes and so as to the
diet of these crabs, they have been observed eating some
regular things like snails and algae, but they have also
been observed engaging in brew rutle cannibalism. You can find
(20:02):
some video footage of this. Uh. It's it's of a
particularly frenzied quality. It's just sort of like a big
murder puddle of pale crabs ripping legs and claws off
and and running away with them. Uh and and and
of course in addition to eating other things in their environment.
But on this expedition, footage was captured of these crabs
(20:23):
doing something a little gentler. They were appearing to groom
one another, eating bacteria off of the shells of con specifics.
So for example, you can see one crab going up
to another crab's leg and just sort of picking at it,
just picking it, not pulling the leg off and running
away with it, as they might be wont to do
(20:43):
in another situation, but just sort of like grazing along
the outside of the leg, getting some of this, uh,
this bacterial matting off of the surface of the of
the exoskeleton. And this is really interesting behavior. It makes
me wonder, like, what does this indicate about the nature
of the crab? Is it possible this could have some
(21:06):
kind of social role within crab society? Like the social
grooming behaviors of primates. I mean, on one hand, that
seems kind of unlikely because these are you know, these
are crabs. They're not they're not social mammals, um, you know.
So it could just be that bacteria is delicious and
here are some right now on on my on this
neighbor's leg. But I guess we don't know that this
(21:27):
kind of thing. I'd be interested to see more research about,
like could there be a role for some type of
social grooming within these within these deep see Arthur pod communities. Interesting. Interesting,
Now I had in the background here, Joe, I had
to do some quick research. And first of all, I
can confirm that the RV Falcore is in fact named
(21:49):
after the Wish dragon in The never Ending Story. Um.
It was. It was originally called the Cea Falcon, but
then it was retrofitted um later um and I believe
two thousand nine or so, and then it was renamed
the foul Core. Now the name Foulcore. Incidentally, Falcore is
the English uh name for the Wish dragon in the
(22:12):
English translation of Michael Linda's The Never Ending Story. In
the German the name is fukor fuc Hu. Are derived
from the Japanese term for lucky dragon fukur you uh
if I'm saying that correctly, And apparently it was changed
in the English translation because, um, the name future sounds
(22:33):
too much like an English language swear word. Okay, well,
I I feel very educated now. Um the way, did
they change the name of the type of dragon in
the movie because I remembered it from the movie as
being a luck dragon? Is it a wish dragon? In
the book? I might have accidentally said wish dragon just now,
but he is. He is a luck dragon. Wish dragon
(22:56):
is is a is a different film that I've also
watched recently. We watched all the dragon films. Okay, we'll
steady sailing to the falcore. But let's get back to
the world of crabs. What else do crabs eat? Okay, well,
so we talked about them growing bacteria on themselves and
eating it off of themselves, and then in some cases
(23:16):
performing grooming like behaviors where they graze bacteria off of
each other. But I want to move on to another
parallel finding. So okay, if you are even the slightest
bit crab curious, you probably know a bit about the
type of crabs known as spider crabs. This involves many
different species, all belonging to the super family known as
Majoi data. They're called spider crabs I think because their
(23:40):
legs can get very long and spind lee, so in
some cases they actually do look like spiders. One of
these animals, maybe the most remarkable spider crab is the
Japanese spider crab or macro chira camp Ferry, which is
the largest extant arthropod in the world. So this is
an ocean dwelling crab that still exists today. It's not
(24:01):
some you know, devonian, your yptorid, giant sea scorpion or something.
You can find these out in the ocean still, and
the largest one on record had a leg span of
around three point eight meters or more than twelve feet,
and it weighed something like forty something pounds. So these
things are enormous. They're mostly legs, so you know, they're
(24:22):
not like a solid mass that big, but if they
spread their legs out, it is it is bigger than
human body. Yeah, you can often find spider crabs at
at aquariums, and they always need to look at I mean,
they don't do much they're they're they're they're not really
action packed, but they're very impressive specimens. But there's actually
another interesting thing about this superfamily, the Majoidea. About three
(24:45):
quarters of the species in the superfamily are examples of
what is known as decorator crabs. Decorator crabs are animals
that live in symbiotic relationships with many different kinds of
sessile organis sums by attaching those organisms to their exoskeletons. Rob,
(25:05):
I've got some images for you to look at. Uh.
There are many different kinds that live in relationships with
many different kinds of other species, but generally a decorator
crab wears other plants or animals as clothing on the
outside of its shell as a form of camouflage to
blend into its surroundings. And it does this by hooking
(25:26):
these other organisms onto little bristles on its exoskeleton called
ct S E T A E, which I've seen compared
to velcrow, So this might be a sort of natural
precedent for for velcrow technology. There are lots of different
kinds of other creatures that get roped into this. Some
particular species of decorator crabs, uh, prefer algae, some prefer sponges,
(25:50):
some look for certain bryozoans, and some like anemonies that
can sting. Oh yeah, I think. Yeah. There's been some
some interesting studies we've probably talked about in the show
before about these uh, these anemone wielding crabs. Uh. And
then what what? They usually have one on each claw
and then if one gets taken away, they can care
one in half to have two again that sort of thing.
(26:12):
Were these the boxer crabs? Yeah, I think so. Well, yeah,
so that example in particular of anemon ees that can
give you a hint that sometimes these decorations on the
outside of the shell do more than simply camouflage the
animal as it hides among the rocks and the other
flora and fauna populating the sea floor. Some of these
decorator crabs select organisms that play a specific defensive role.
(26:37):
So I was looking at a table of findings of
this sword published in a book called Animal Camouflage, Mechanisms
and Function edited by Martin Stevens and Semi Mirlita. And
this was from Cambridge University Press in two thousand eleven,
and it lists a bunch of different examples of different
types of majoid crabs along with research identifying their preferred
(27:01):
decorations and possible reasons for that preference. So, for example,
there is a type of crab known as the innocous
Philangium or the leeches spider crab. It appears to prefer
a type of brown algae known as Dictyota dick atoma
for the parts of its body most exposed to predators.
And it turns out that this species of algae is
(27:24):
not only good camouflage, it is chemically noxious, So it
hides that this crab hides the vulnerable parts of its
body behind something that predators would probably find disgusting or
even poisonous. Uh. Maybe, like if you were trying to,
you know, protect yourself from tigers by covering your back
in bottles of bleach. You know, a tiger gets in
(27:45):
there and starts biting it's it's not gonna want any
of that. Also along these lines, there's an Atlantic spider
crab called Stino c o ops for cot Us that
preferentially attaches a species of stinging anemony to its carapace.
And in both cases, these decorations would appear to provide
additional defenses. Beyond just masking the body in the environment.
(28:05):
But the crab from this list that I wanted to
focus on has a different relationship with its preferred decoration organism.
It likes to eat its own camouflage. So the animal
in question is known as noo Mithrax ursus, or the
hairy seaweed crab. I think the Latin name of its
of its species ursus, implies that it's also known as
(28:26):
the bear seaweed crab or sign bear. And folks, I
just want to say, off the bat, this is a
beautiful crab. In some cases it looks like a cartoon
animation of a crab being electrocuted. It's got like animated
electricity lines all around it. Also sometimes it looks like
a burst of fireworks from hell. It is just a
(28:49):
gorgeous Arthur pod. And I can definitely see where the
name comes in because it it is it looks like
it's furry like the bear. You know, yeah, totally um So,
it has some natural hairs that that stick out from
its exo skeleton. But it's also generally well actually not
in all environments, but in some environments it covers itself
in uh in. In these decorations that give it this
(29:11):
additionally hairy look. So according to an entry, I was
reading about it from the Museum's Victoria database the Australian
Um Natural History Museums. UH. These are found in rocky
shores and reefs around New Zealand and Southeastern Australia. And
I was further reading about this this species in a
(29:32):
in a research paper published in the New Zealand Journal
of Marine and Freshwater Research in nineteen ninety four by
Chris Woods and Colin McClay called masking and Ingestion Preferences
of the spider crab not a mythrax Ursus. And what
the researchers here say is that in laboratory tests, specimens
of this crab not a mithrax Ursus were found to
(29:54):
have preferences when it came to which organisms they would
mask with. So it wasn't just any algae. There are
certain kinds of algae they like to put on their shells,
and specifically it was types of branched algae like hallop
terrorists specific era and Corallina office analis. And I actually
(30:14):
just want to read in full a part from the
introductory section of this paper that describes the process of
attaching pieces of algae to the body because I found
it really fascinating to picture this routine as the crab
does it. Uh and so too. As a note to
help understand what I'm about to read here, the words
chili and chella pads refer to the claws. The chili
(30:36):
are the claws and the chili pads are the claw legs.
Pad isn't foot, so the authors write quote. The masking
behavior of in Ursus begins with the selection of a
clump of algae. The crab then selects a single piece
of alga, using the chili in a cella over cella
technique to correctly measure the piece of algae to the
(30:58):
required size, So the measuring it out using their claws
as a as a as a ruler. Basically, this piece
of alga is then snipped off using the cheli and
transferred to the mouth parts, where the cut end is
roughened and trimmed of any projections, while the uncut end
is held by both chelipeds. Okay, so holding it in
(31:19):
the claws and then chewing on the snipped end, putting
it in the mouth parts to chew on it. Then
once you've chewed up the cut end good uh quote.
One cheli pad is then used to transfer the piece
to a part of the body. Attachment is accomplished by
rubbing it against the hooked set so that the cut
end becomes entrapped by the set. If the algal piece
(31:40):
does not attach, it first is transferred back to the
mouth parts to be manipulated, and then taken back to
the side of attachment and rubbed against the hook set
until it attaches. If the piece of alga fails to
attach after a number of attempts, it is discarded and
a new piece is selected. I don't know why, but
I found this kind of surprising. Something seemed kind of
comple x and and and crafty about this process. Yeah,
(32:04):
I mean it. It's it's a process that may seem,
you know, out of beyond the abilities of what we
might might generally attribute to a crab. But then again,
we think about the way they eat, which we discussed
in the first episode, and it does sound like a
natural extension of that, Like this is an animal that
is very that excels at taking things apart um uh
(32:26):
you know I usually so it can fit those things
in its mouth, uh, and can consume it but this
is kind of a specialized version of the same thing,
manipulating living things um and then using the pieces of
that thing that you have manipulated. It ends up being
this kind of kind of like biomancy that the crab practices. Yeah, totally.
(32:48):
I just love that detail about it chewing the snipped
end of the alga in order to roughen it so
that it attaches to the vel crow on its back. Yeah. Now,
another interesting fact this paper mentions is that there is
a lot of turnover in the crabs algae mask. Apparently
not a Mithrax ursus replaces a good ten to twenty
of its algae cover every twenty four hours. That would mean,
(33:10):
you know, every roughly five to ten days, it's got
a new coat of algae on it. And apparently decorator
crabs that use algae in particular can be very strategic
about its benefits as camouflage. For example, previous research, so
not this study, but other studies they cite, had found
in some decorator species that when you put a crab
(33:32):
in a tank where it is surrounded by algae that
doesn't match the color of the algae on its current mask,
it will basically strip itself of the old algae and
redecorate itself with the new algae to match its environment.
And also research has shown that when given the option,
crabs will tend to stay hidden within masses of algae
(33:54):
that match the color of their existing mask. So these
crabs can distinguish between different types of masking materials and
they can make calls about masking and hiding behaviors to
maximize the camouflage effects. Wow, that's really it's really impressive. Yeah,
it's it. It goes beyond just this near sort of
automatic behavior that's taking place with anything that it happens
(34:18):
to come across, right, So, yeah, it's not just sort
of like rubbing up against a bunch of algae and
getting it stuck on there. It's picking the algae that
will that will do the best job of camouflage. But
the researchers in this study found a different kind of
discrimination in the selection of the masking material when it
came to Noto Mithrax ursus. They found that the algae
(34:40):
species the crabs preferred to mask with were the same
ones they preferred to eat. So if you make like
a ranked list of all of the algae that the
crab will go to first to eat which ones doesn't
like to consume the most That is going to be
the same as the list that it will choose to
put on its carapace and down its legs. So in
(35:02):
a way, here it looks like the camouflage is doubling
as food storage. This crab is hiding behind a mask
of its own lunch, so the algae on its back
will help it blend in with its environment, make it
look like a bunch of seaweed rather than a crab,
so predators are you know, are less likely to spot it.
(35:23):
But then also it can eat that seaweed. It can
eat that algae if it gets hungry. It's like if
we were to imagine a like an army sniper in
one of those gilly suits, but they insisted on only
camouflaging themselves with their favorite leafy greens so that they
could snack on it whilst while stalking, you know, and
(35:43):
and and waiting on their their target to appear. This
gilly suit is a super food kale only kale gilly suit.
I love it, though I guess it does make me
wonder maybe there is an answer to this. I'm not sure,
but it makes me wonder which way the adaptation goes, Like,
how how did it end up matching the food preferences
and the masking preferences? Um? So, like, was it because
(36:05):
a certain type of algae was the best, you know,
provided the best camouflage cover, the animal evolved to prefer
eating that kind or was it the kind that's most
delicious and nutritious it evolves to prefer for masking. Yeah,
that's a great question. Yeah, the crabs are silent on
the matter than all Right, up next we have this
(36:33):
will be a shorter little section here, but this is
something you you you pinpointed and then I followed up
by by looking at a source on it. But this
is the idea of crabs eating. This is so much
crabs eating something remarkably different, but crabs doing it in
a way we didn't expect. And that's crabs eating quote
(36:55):
unquote eating through their gills. Yeah, this is interesting, so
circumventing the look at mouth parts that you don't even
have to raise a jaw leg for this meal. Right,
So this concerns the invasive or at least invasive in
um uh North America and I believe in Africa as well. Uh.
The the invasive green shore crab, which we've discussed on
(37:16):
the show before. I believe in their native European waters
they are sometimes harvested for food, and there have been
efforts in North America, where it is certainly invasive, to
encourage its use in cooking. You know, what are some
culinary uses for this, and I think there have been
some some ideas of using it as like a uh
you know, like like a soup base and so forth. Um,
(37:37):
that's the same tactic you see with like invasive lion fish,
hinging on the fact that if you really want humans
to make a species disappear, make them desire that species
for some reason or another, such as making it an
ideal main course at a dinner. Sure. I think we've
actually covered the green shore crabs in a different capacity
on the show before. I don't remember what it was, though,
(37:58):
so as point it out in a two thousand seventeen
study from the University of Alberta, the green crabs are
pretty snazzy consumers in their own right because they can
again quote unquote eat by absorbing nutrients, specifically the amino
acid um loose sign across their gills. And this was
(38:19):
the first demonstration of crustaceans being able to do this.
Now that the crabs are notoriously hardy, as you often
see with an invasive species, um, so their bility disability
might enable them to survive long periods between meals. So
I don't have anything to eat, but I can absorb
some some necessary amino acids, or it might help them
(38:39):
cope with changes in salinity. So offsetting salinity changes via
the amino acids that they can absorb just straight through
their gills. Okay, so they would not be fully like
sucking in chunks of food through their gills and eating
like that. It's it's specifically getting these particular amino acids,
these particular nutrients out of the water around them as
(39:01):
they breathe. Yeah, so you know that's again whine we
put eat in quotation marks here. I guess it's kind
of like our humans eating when we absorb vitamin D
via sunlight, that sort of thing. Are we are we
eating when we get a you know, some sort of
a vitamin injection or something. Yes, Okay, I've got something
(39:22):
I was wondering about. Rob You may have seen it's
a very popular genre of internet video, uh feeding crabs
human food you know, I don't really think I've seen
any of these. What kind of foods are they feeding
them in these videos? Oh? Everything I've seen. I think
I've seen crabs eating pizza. I've seen crabs eating you know,
fruits and vegetables and chips and all the giving crab
(39:46):
derito is probably I don't remember all the specifics, but
you know, I've seen a good bit of this in
my day. Clearly, it's funny to look at, you know, crabs,
the kind of it thinks it's people sort of thing,
right exactly, A crab eating a rito is inherently comedic.
I don't know if it's good for the crab though,
then again, lots of crabs or scavengers, you know, they'll
eat what what they can get. Um. So, so I
(40:09):
guess I'm not too worried about the crabs. But but
but I just wondered, is there anything interesting to cover
about the phenomenon of crabs eating human food? All right,
so we cannot speak for all crabs. We will not
speak for all crabs. But one fun place, uh to
look for some answers that I thought would be to
(40:30):
look to the realm of hermit crabs as pets. Joe,
did you ever have a hermit crab as a pet?
I did not, did you. I've always wanted one, but um,
it's never been permitted. I'm always like that looks that
could be a great pet, and and and whoever is
in my life is always like, I don't know if
you need that, and they're they're probably correct. So you
(40:51):
mean your family now is preventing you from getting hermit crabs, right?
I think it's the Yeah. I think the argument is
a hermit crab is either too much pet or not
enough pet. So it's either a situation where like, uh,
you really, you know, ask yourself, do we have space
and time for this creature to live in our life
as well? Or it's a question of is there something
(41:14):
more exciting we could have, like a lizard, And that's like,
that's where we are now. We have a we have
a leopard gecko. We skipped over hermit crab and went
straight to leopard gecko. This is a vertebrate household, so
to be clear, there are more than one thousand hermit
crab species and you can roughly divide them all up
into marine hermit crabs and terrestrial hermit crabs. Uh, so
(41:34):
you're you know, you're your sea dwellers and then your
land dwellers. And there are a few different species that
are popular pets from either category, but the ones most
likely to encounter human food are of course those terrestrial crabs.
So I thought I might look at some terrestrial hermit
crab feeding guides for some ideas. Okay, so I went
to the spruce pets. This is I think it's from
(41:55):
the same people who like the sprucey heats, uh, And
they point out that commerce hermit crab diets are probably
the best way to go if you're feeding a hermit crab,
because these are balanced and they contain everything that they
might need because in general, you know, matching up with
pretty much everything we've been talking about here, they're going
to have a very diet their opportunistic land roving omnivore,
(42:16):
so they're gonna eat a little bit of this, a
little bit of that in the natural world, and you
need a food source that reflects that they're on the
seafood diet. I seafood, I eats it pretty much. Yeah,
So they recommend I'm going to roll through a lot
of foods here. They recommend such fresh foods as mango, papaya,
coconut fresh or dried. And I have to add that
(42:37):
I can certainly back up the coconut suggestion because um,
I got to watch a whole bunch of hermit crabs
go absolutely crazy over a busted open coconut once, and
it was it was amazing. It was a feeding frenzy.
Where were you seeing the wild hermit crabs? I believe
this was in Belize if memory serves. Oh, okay, all right,
But in addition to this, apples, apple sauce, bananas, grapes, pineapple, strawberries, melons, carrots, spinach, watercress,
(43:04):
leafy green lettuces, but not iceberg lettuce because you know
the the nutrient issue there. Uh, Broccoli, grass leaves, strips
of deciduous tree bark, unsalted nuts, occasional peanut, butter, raisins,
dried seaweed, crackers, unsweetened cereals, plain rice cakes, plain popcorn
(43:26):
on occasion, freeze, dried shrimp, freeze dried plankton, brian shrimp, fish,
food flakes, and much more. Okay, so it looks to
me like this, Uh, this list of suggestions from this
website is suggesting a wide range of different kinds of foods,
but seems to be avoiding things that have added sugar
(43:47):
or salt. Yeah. They point out that the crabs may
seem very interested in salty and sweet snacks like chips
and sweet breakfast cereals, but these are to be avoided.
They say also stay away from dairy products, which makes
sense when when when would have a crab get a
dairy product in the natural world. Um. And they say
that the hermes are generally gonna be game for fresh
(44:08):
or dried fruits of any kind, but some experts advise
against highly acidic or citrus foods, so like maybe don't
give them a limon or a tomato. Also, starch veggies
like potatoes are to be avoided um as well as
again low nutrient iceberg lettuce. What I all this hating
on iceberg lettuce? I love iceberg lettuce. I'm gonna go
(44:28):
out on a limb right here. I'm gonna say iceberg
lettuce is awesome. I mean it, iceberg lettuce can be awesome,
But the question is what are you getting out of it? Well,
I don't know what you're getting out of it nutrient wise,
but it's delicious, crunchy crunchy goodness. Alright, fair, fair enough,
just keep it away from the hermit crabs. Um. Now, also,
hermit crabs require calcium, So remember that bone gnawing we
(44:50):
mentioned from the last episode involving other crabs kind of
plays into into this scenario. Uh, calcium edition probably not
gonna come as a surprise to many pet owners out there.
I know. With our leopard gecko, we have to we
have to shake its crickets up in a bag with
a calcium powder to ensure there's getting enough calcium, and
then also leave some calcium out for it in a
little tiny dish. Um. But with crabs you can end
(45:14):
up using reptile ready calcium supplements like this. But also
you might end up using something like crushed oyster shells
or cuttle bone as something that they can use to
get their their calcium. Oh yeah, okay, So tying it
back to the last episode, I was just remembering the
suggestion this was not proven, but it was it was
hypothesized that maybe one reason duck built dinosaurs had been
(45:36):
eating a bunch of crustaceans that might have been crabs
or some of their you know, related crustaceans that have
these these hard shells. Was that they were looking for
certain nutrients types of protein or specifically calcium as part
of their breeding and reproduction cycle. Yeah. Now one more,
one more note from this spruce article because it's just
(45:56):
it's so crab. I love it. They say, quote hermit
crabs are able to find their food in two ways,
by smelling the food and by seeing other hermit crabs
eating hermit crab dietary peer pressure. Yeah, so they might
be like I detect food over there, or it's like
that hermit crabs eating something I'm in, I'm gonna go.
(46:18):
I'm gonna go try and steal some of that. All
the hermit crabs like Billy gets to eat iceberg lettus
Billy gets to eat pizza. Yeah. But obviously, I, like
I said, I do not have a hermit of a
pet hermit crab. I've never had one. I've just gotten
to observe some in the wild and you know, look
at them in pet stores. So, if there are any
hermit crab enthusiasts out there and you have particular thoughts
(46:38):
on this, if you can tell us, uh, you know
what foods your hermit crab prefers the most, which ones
you you like to give them definitely right in and
let us know, I'd I'd love to hear from that. Really,
anybody out there with with crab expertise or crabs pertise,
uh you know, right in? Have you ever had part
of your body eaten by hermit crabs? What was that? Like?
(47:01):
Hermit crabs do they just have a lot of character?
I love I love watching them. Yeah. Actually I recall
one Nature documentary segment I honestly don't remember what it
was from, but I think it was something narrated by
by Attenborough. Um. But it was a segment that was
showing hermit crabs forming a chain of shell trading, so
like they were all trying to trade shells to get
(47:25):
a bigger shell, and they formed up in a line
essentially to each switch into the next one's shell. Yeah,
there have been essentially like biology economics articles that have
looked at this, like how do they go about, um,
you know, trading up on their their shell size? And
then you know, because if one leaves its shell for
a bigger shell, then that opens up a shell for
(47:46):
another growing hermit crab to take advantage of it. It's
it's really fun. So the adaptation there I guess would
have to involve the hermit crab observing when a bigger
hermit crab is likely to be leaving its shell for
for a bigger one. So I yeah, that would take
some kind of social observance, kind of like what you're
talking about with the hermit crabs watching other hermit crabs eat. Yeah,
(48:09):
I mean I think also they're they're all about stealing
as well. If so, it's it's a it's a crab
kind of a crabby crab world. But who comes up
with these rules? You can steal somebody else's shell, but
you can't eat iceberg let us. Now, they will eat
the iceberg. It's not that they don't want it, I think.
I think the idea is like, they will eat it,
(48:30):
but it's just they deserve better. Okay, coming up soon,
we're gonna do a whole episode on iceberg let us.
It'll be about how iceberg let us is the king
of foods. It's amazing. I know that what iceberg let
us must not occur in nature. Whoever created the strain
of vegetable is really deserves great credit. All right, Well
(48:51):
we're gonna go ahead and close it out there. But yeah,
again right in. We'd love to hear from you. Let
us know if there are other examples of curious crab
cuisines that that we were not familiar with. It didn't
have time to cover here. We will mention it in
an upcoming listener mail episode. Also, yes, hermit crab owners,
right in and tell us all about your babies. In
(49:12):
the meantime, if you would like to listen to other
episodes of Stuff to Blow Your Mind, you can find
us in the Stuff to Blow Your Mind podcast feed
that it gets found anywhere you get your podcasts. Just
you know, make sure you subscribe and you can get everything,
including our core episodes on Tuesdays and Thursdays, our listener
mail episodes on Mondays are artifact short form episodes on Wednesday,
(49:33):
and then on Friday you get Weird How Cinema. That's
our time to just talk about a strange film of
one sort or another. Huge thanks as always to our
excellent audio producer Seth Nicholas Johnson. 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. Stuff
(50:02):
to Blow your Mind is production of I heart Radio.
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