From the Vault: Crabs Eat Everything Around Me, Part 1

In this classic 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! (originally published 11/16/2021)

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Episode Transcript

Speaker 1 (00:05):
Hey, welcome to Stuff to Blow your Mind. My name
is Robert Lamb and I'm Joe McCormick, and it's Saturday.
Time for an episode from the Vault. This one originally
published November. It's called Crabs Eat Everything Around Me Part one.
It's about you know, it's about crabs eating stuff. I
don't think there's any simpler way to put it than that.

(00:26):
My welcome to Stuff to Blow your Mind production of
My Heart Radio. Hey you welcome to Stuff to Blow
your Mind. My name is Robert Lamb and I'm Joe McCormick.
And today we're gonna be talking about crabs. I think

(00:47):
this will be the first episode in a in a
series that we're doing here at least two parts to this,
because the crabs are ravenous and we're gonna be talking
all about crabs eating things. You know, this is kind
of a holiday tradition for so I figured how many
years ago it was that we did uh, we did
Christmas Crabs. We talked about the Crabs of Christmas Island
as our Christmas episode, and and so it feels appropriate

(01:09):
that as we enter into the holiday season here with
in November and December, that we should return to the
world of crabs and the feasts that crabs engage in.
Have you ever noticed how the crabs come earlier every year?
At least it feels that way. But yes, anyway that
this will be a feast day of an episode because
it will all be about crabs feasting sometimes things feasting

(01:30):
on crabs, mostly what crabs themselves feast on. It's funny
how crabs are are a natural source of feasting related content. Uh, Rob,
I I think you saw my note about this beforehand,
but I discovered the strangest Google results phenomenon before we
came in here. What I found out earlier today was

(01:50):
that when I do a Google search for crabs, it's
five letter word crabs. You'd think the first result would
be what like Wikipedia page for this animal, but no,
the first result is seafood restaurants featuring crabs. They're trying
to sell me some crab legs and drawn butter. And
then the second result is the is like a health

(02:12):
node about pubic lice. And then finally the third thing
in the result is about the actual animals, the decapod crustaceans. Well, um,
after you mentioned this, I had to try it out
for myself. And and granted I'm not going in like fresh,
you know, I do use Google quite a bit um. Uh.
So for me, when I did a search for crabs

(02:33):
c R A B s um, the number one hit
is sponsored seafood content, but then it's the wiki for
the decapod crustaceans, and then it's pubic lice in number
at number three um, and then it's more pubic lice,
and then it's some stuff about the crab nebula I
think video content about the crab nebula uh, and then
it's back to pubic lice once more, before rounding out

(02:55):
page one search results with the Britannica dot com article
about decapod crustaceans. Okay, so as our top three go basically,
Google just thinks I'm going to be more interested in
uh in in the lice than you are. I have
no idea. I mean it could. I mean we were
both probably searching for crabs all morning um and and
perhaps yeah days before as well. So it seems like,

(03:18):
I mean, I don't know how these algorithms work, but
it seems like they would have gotten into their robotic
minds that these are gentlemen who are interested in decapod crustaceans,
and we should serve them up even more of it. Guy,
I don't know, it's all mysteries in there. Who knows
the mind of the machine crabs that that order all
those results for us? Um, But I wanted to come
back to uh this uh image in amber. So there's

(03:42):
a study that was just published in Science Advances earlier
this year by Javier lukeway at All, and it was
called Crab and Amber reveals an early colonization of non
marine environments during the Cretaceous. So this discovery concerns a
fossil found in a piece of amber mind in modern

(04:03):
day me and Mar dating back roughly a hundred million
years or so, so squarely in the middle of the
Cretaceous period, containing a remarkably well preserved specimen of a
crab bearing the author's note, large compound eyes, delicate mouthparts,
and even gills. Basically it's wholly intact. The whole thing

(04:24):
is in there. Yeah, it's quite impressive looking in the
way that it is um its body. It's position too,
it looks like it is like throwing up its clause
and a defensive position that we've all seen. And I
think or you haven't seen it in person, you've probably
seen a picture of it, of a crab like on
the beach saying stand back, mammal, do not make me
pinch you. Um. So it's as if, through you know,

(04:46):
across uh, this is vast stretch of time, the crab
is warning us to stay back with such ferocity that
the very forces of geology like conspired to preserve this
this uh, this ants it's doing. And yeah, maybe I
maybe I sound silly, but I give this image five
out of five coal hods. I am profoundly stirred by

(05:08):
this crab trapped in amber. And and not just because
it you know, it looks like that haunting mosquito and
amber prop from Jurassic Park. But but there's something a
little bit more to this too, because it raises these
questions like how did a crabred million years ago get
stuck in tree resin to become part of a fossilized

(05:30):
piece of amber. We don't know the answer to this,
but the researchers hypothesized, well, maybe this was a crab
that lived a partially arboreal lifestyle. There are crabs today
that climb trees as part of their lifestyle. So maybe
this crab was climbing trees for some reason. Uh and uh,
and and maybe it's also just because it causes you

(05:51):
to realize that crabs existed and we're already beginning to
come out of the oceans to move inland from the
beaches hundred million years ago when dinosaurs were at their apex.
And I always love those realization moments where you have like, oh, yes,
animals of this kind and this kind actually did live
alongside one another, terrestrial dinosaurs and terrestrial or semi terrestrial crabs.

(06:17):
And Robert, I think you'll be very familiar with the
the the did they fight mindset. Right as soon as
you imagine that, the my sort of like eight year
old boys brain starts going, did they ever fight each other?
Dinosaurs versus crabs? I don't know how much of a
fight that would have been, but I guess more more
relevantly I could say, did they ever eat one another?

(06:38):
And Uh, you actually gotta give you credit because you
turned up the source on this for the copper Light
study that found a pretty good case that yes, at
least the eating was going one way. Yeah, but the
details of this I was surprised at because you know
not not to say that that some like smaller you know,
beach combing dinosaur wasn't also hunting and gobbling up crabs.

(07:01):
But the evidence here points to a different mode of consumption, right.
So this is a study published in Scientific Reports in
The lead author was a professor Karen Chin, who is
Curator of Paleontology at Colorado University Boulders Museum of Natural History.
And uh so this was by by Chin, Feldman and

(07:24):
Tashman called Consumption of Crustaceans by mega herbivorous Dinosaurs, dietary
flexibility and Dinosaur life history Strategies. So this is a
copper light study, and you've gotta love a copper light study.
Copper light, of course, is fossilized animal dung. This is
dung that has become a mineral of the Earth. And

(07:44):
the top line on this is that, uh collections of
fossilized dinosaur feces from seventy five million years ago found
in modern day Montana revealed that some giant herbivorous dinosaurs
weren't always strictly herbivorous. Now, this would not be the
first time a subject like this has come up on

(08:05):
the show before, I think It was in our episodes
on the Minotaur that we talked about evidence of bovines,
cows and bulls and related animals sometimes eating flesh and
in addition to their mostly vegetable diets. But it looks
like maybe something similar was going on with giant herbivorous dinosaurs.
So these feces probably belonged to hadrosaurs or the duck

(08:27):
build dinosaurs. And it looks from the contents of these
copper lights like these giant herbivores sometimes would supplement their
vegetable diets by eating rotten wood and crustaceans. You can
tell by these, uh, these remains preserved in the fossilized
dung which are full of wood, fiber and crustacean shells. Now, again,

(08:50):
this this raises these wonderful questions like how did this happen? Why?
And you could imagine it's possibly some kind of accident,
maybe a duckbill dinosaurs eating a rotten log for some reason,
trying to get some kind of nutrients from all this
rough rotten wood, and the rotten log just happens to
be full of crabs. But to come back against that,

(09:13):
against the accident hypothesis, I just want to read briefly
from the press release describing this study. Quote, the size
of the crustacean shell bits in the copper lights indicate
the crustaceans were at least two inches in length and
perhaps larger. Uh. And this is according to the lead author,
Karen Chin. Individual crustaceans comprised from twenty six of the

(09:35):
width of a common had restored beak, suggesting it was
unlikely that crustaceans were unwittingly swallowed. Uh So, the ideas,
it looks like whatever these crustaceans were, maybe they were crabs.
We don't know for sure what they were, but there
have been fossilized crab claws found from around the same
area and going back even further in time, So there

(09:58):
were crabs around these station. Shells could have belonged to
crabs that were smashed up too much in the in
the copper light to know for sure, but they could
have been crabs, and they would have been big enough
that it kind of seems unlikely they just accidentally went
into the hadrosaur's mouth. It seems like the hadrosaur would
kind of have to choose to eat the crab. Yeah,
I mean, I'm also For me, it just makes me wonder,

(10:20):
like what was the digestive system of a hydrosaur, Like
it was just it seems like an industrial processing plant.
You know, it's just rotten wood. Uh, it's all these
these are these these fairly large like whole crustaceans and
or their shells embedded in it, and you just you
just eat that down because you're still hungry. And it
may not have been about just obtaining raw calories like

(10:42):
they may have been searching for a specific nutrient like
we see in some other cases of otherwise herbivorous animals
sometimes eating say bones or something where they're looking out
certain types of minerals, maybe calcium or something. It could
have been the case that maybe eating eating crustaceans like
crabs for the drsaurs was linked to the reproductive cycle.

(11:02):
They may have been seeking to bulk up on calcium
or something. We don't know though, but oh whatever the
answer there, I just I love it. So mega herbivorous
or so called herbivorous dinosaurs eating crabs or crab like
crustaceans seventy five million years ago and crabs a hundred
million years ago getting frozen in amber for all of time. Uh,

(11:23):
it just it just fills my you know, I got
butterflies under my skin, all over my limbs. It's like,
this makes me so happy. Yeah, I mean for the crabs.
Though this is just another couple of pages in the
history of the crab planet, well right, because it all
it raises the question going the other way, the one
we're saying we didn't know if we could answer. But
so it looks like some dinosaurs in some cases eight

(11:46):
crabs or crab like animals, other crustaceans. But the other
question would be did crabs ever eat dinosaurs? I don't
know about you. I could not find anything, any evidence
to directly address that question. As far as I know,
there is no physical evidence anybody's aware of, uh, to
settle this issue. But I would say, if we can't

(12:06):
find an answer to the question based on everything else
we're going to talk about in the series, I think
I would argue that in the absence of any evidence,
our default assumption should be yes. I believe so. I
think based on what we know about the nature of
crabs in general and the sort of things they do eat,
it it only makes sense that that they would they

(12:26):
would partake of dinosaur meat if they came across it
in their environment Alright, well, I say from here on out,
for the rest of the series, we're just going to
be looking at crabs eating all kinds of stuff. So,
uh so, rob if you're ready, let's let's begin the
crab feast. Yeah. But like just like with human feast,
it's not enough to know what you're going to be eating.
It's it's also about how you're going to eat. Uh,

(12:48):
you know that, So we should we should probably start
there with how crabs go about, uh consuming their various feasts. Right. So,
crabs are of course a verse subgroup of the order
of decapod crustaceans, So the decapod as in having ten feet,
they are crustaceans. So there, you know, creatures with an exoskeleton.

(13:10):
In order to grow bigger, they have to molt, so
they have to shed their hard exoskeleton and come out
with a soft one while they can rapidly increase in
size and then reharden that. Crabs of course live in
all kinds of environments. They originally come from the ocean,
but over time and evolutionary history, like we saw with
the crab preserved in amber, they started to move out
away from the ocean and eventually into freshwater environments, and

(13:33):
there are even land crabs. So as to the question
of how and what do crabs normally consume, well, there
are a lot of different species of crabs, and some
of them have different dietary specialization, so there's no one
answer to that question. But if you just want to
sort of be general overall, it seems like the majority
of crabs are not especially picky. Uh. Many crabs appear

(13:56):
to be omnivorous opportunists who will eat pretty much anything
they can shove into their mouths, and this can include
everything from vegetation just gobbling up algae and fresh plant
material leaf litter to uh to eating meat of course,
scavenging scavenging carry in which crabs do a lot, or
just getting little bits of organic or animal detritus, to

(14:19):
actively hunting live prey with their claws, which some crabs
do so as to diet. Crabs are all over the map.
But the next thing I wanted to mention this was
new information to me when when I was getting ready
for this episode. So animal bodies, you know, they've usually
got some kind of special equipment to help them extract
the maximum amount of nutritional value from their food, and

(14:41):
this often involves either chemically or mechanically breaking down the
food from its original form, often to increase the surface
area or the ease of access to nutrients by the
digestive system, So there might be some kind of chemical
breakdown as well. So you know, you know, you know
the equipment. You've got Humans have teeth that we chew
with and that that mashes food up and increased surface area.

(15:04):
You've got gastric acid secreted by the cells in the
lining of your stomach. But then you know they're all
kinds of other strategies. Spiders will vomit digestive enzymes over
and into their prey to uh sort of reduce the
nutritious parts down to a fluid or mush that they
can then slurp up with the mouth. And they also
do have a form of chewing with their jaws, which

(15:26):
are called chillissory. But crabs have one of the most
glorious digestive aids I think I've ever read about. So
if you ask the question do crabs have teeth, I
think the answer would have to be yes and no
in a couple of ways. So Obviously, crabs do not
have teeth like us. Uh. They typically eat first by

(15:49):
using their claws to tear food into small chunks before
bringing it up to their mouth parts, and then they
usually have a number of different moving mouth parts. These
consist of um these things called maxilla heads, also known
as jaw legs, which are sort of like hands within
the mouth. These are are modified a little leg parts

(16:10):
that will sort of grab bits of food and pass
them inward and onward to other parts of the mouth
known as the mac silly and the mandibles, which can
further shred the food apart into smaller pieces that can
be swallowed. But then once the food is swallowed, it
is inside the digestive system where the most amazing feature appears,

(16:31):
and it's this. Crabs, along with other related crustaceans, have
an organ known as a gastric mill, which is more
or less teeth inside the stomach. They've got gut teeth.
They can chew with the insides of their stomachs, And
this is another one that really got me. This is
also worth googling some pictures of if you can, because

(16:55):
there there are some uh some photos you can find
on the Internet of like gastric mills, how having been
extracted from the inside of a of a crabs digestive system,
and they it's hard to describe how they look. They've
they've got the kind of they're like a semi translucent
pinkish orange, uh sci fi weapon hood. I don't know
it's but it's also kind of beak like. It's very unnerving.

(17:18):
I think, what are the interesting things about about the
way of crab eats? And especially as evident if you're watching,
um it's a close up video of a crab eating,
is that there even more so with other creatures this
there's this sense of meticulous um disassembly. Uh, the crab
is not so much I mean, it is consuming, but
it is also just uh just taking whatever it is

(17:41):
consuming completely apart. It is disassembling matter and putting it
into itself. Well, yeah, the crab makes you think about
how much how much humans actually need to use tools
for the kind of disassembly that they do leading into
into eating say meat or something you know, like so
humans devote a huge amount of their tech know logical
energy over the history of time into creating like tools

(18:04):
for butchery of food, cutting food into smaller and smaller
pieces that are manageable that you can bite into, chew up,
and all that. The crab they've they've got their disassembly
tools right there on their body. They've got the claws,
they've got the maxilly and the mandibles, and then once
the food's inside, they've got additional opportunities for chewing. You

(18:25):
don't have to stop chewing once you have swallowed. So
the way the gastrit mill works is that it's sort
of choose the food from inside the stomach by grinding
it between these hard parts like plates or surfaces that
are moved around by powerful gut muscles. And so while
I was reading about the gastrit mill, I came across

(18:45):
a really interesting piece of research from twenty nineteen that
I just had to mention as as we're going along here,
and this was by Jennifer R. A. Taylor, Maya S. Devrees,
and Damian O Alias published in the Proceedings of the
Royal Society be In in nineteen called Growling from the
Gut co Optation of the gastric mill for Acoustic communication

(19:08):
in ghost Crabs. So the short version of this discovery
is that you've got this animal, the ghost crab scientific
names quadrata, and it will sometimes make a threatening sound
by way of having evolved. Quote a novel stridulation apparatus
on the clause that is used during agonistic interactions. So,

(19:32):
strigulation is any sound that is made by an animal
rubbing pieces of its skeleton or exoskeleton together. The very
common example you can think of is the sounds made
by crickets or grasshoppers. That's strigulation. They rub parts of
their legs or their carapists together, and that makes this
chirping sound that is useful to the animal for some reason,

(19:53):
maybe for maybe for mating, or maybe as warning signals
or something. The ghost crab appears to use this stridge
relation of rubbing its claws as a as a warning sign,
as signs like Hey, I'm threatened, I am dangerous. I've
got these big claws. You do not want to get
near me. But in addition to the strigulation they make
with their with their claws, to quote from the abstract

(20:15):
of this paper, by a tailor at all quote, but
they also produce a rasping sound without their claw apparatus.
We investigated the nature of these sounds and show that
oh quadrata adopted a unique and redundant mode of sound
production by co opting the gastric mill the grinding teeth

(20:35):
of the fore gut. Acoustic characteristics of the sound are
consistent with strigulation and are produced by both male and
female crabs during aggressive interactions. Uh so, yes they are.
Actually they can like chirp like a cricket with the
grinding teeth inside their stomachs in order to have a

(20:56):
redundant way of making this aggressive sound display that they
when they're being threatened. And the authors actually speculate as
to why they would have this redundancy why be able
to make this sound with two different parts of their body?
They write, quote, A key advantage of using gastrixtrigulation over
the claw apparatus is that it provides signal while freeing

(21:17):
up the chel a for postural display and attack readiness.
So you know, basically this this allows you to have
claws out to be maximally visually threatening and maybe maximally
dangerous if a fight actually does start, while still making
the grinding scary sound. So yes, anyway, crabs and related
crustaceans gastric mills. The chewing doesn't have to stop once

(21:40):
you go down the gullet. And like we said, a
lot of crabs are not very picky eaters, So who knows,
maybe maybe if you could be taken apart into small
enough pieces, you would go down the gullet. Than I
guess from here we're going to start getting into the
various meals of the crabs. You know, what do they

(22:01):
use this uh, this fabulous uh equipment for? And I
guess that I was thinking that one of the best
places to start would be talking about crabs eating humans,
because obviously that's going to be one of the most
pressing questions to us the humans, right. Uh, Sure it eats,
but will it eat me? How delicious am I? Do

(22:21):
I deserve to be eaten by crabs? Um? And I
think it's an understandable question. I mean, on one hand,
like we are concerned with with this question with any
creature on some level, you know, we have to have
that that that that box checked off or or empty?
Will it eat me? Uh? Is it incapable of eating me?

(22:42):
Does it want to eat me? Uh? These are always
questions that we have about other creatures in the animal
kingdom and the various horror movies and animal creature flicks
that we uh we watch. They don't help matters either, because,
on one hand, we have our giant crab movies in
which giant crabs, you know, in addition to occasionally wanting
to take over the world or destroy whole cities, they

(23:03):
want to grab people with their claws and either try
to eat them, or it's implied that that crab is
grabbing you because it wants to eat you, or, in
the case of Attack of the Crab Monsters by Roger Corman,
not just eat you but also absorb your soul and
intelligence in so doing. Right, But then, uh, we also
have countless movies in which we see crabs scavenging, uh,

(23:26):
you know, crawling around on the corpses of humans who
have probably been dispatched by some kind of slasher or
some sort of monster that it itself that it that
is not concerned with eating the human. Uh. This is
like a standard scene. And oh goodness, I was trying
to think of specific examples, and I couldn't come up
with one. But I know I've seen it over and
over again. Like cut from the you have a dark

(23:47):
scene with something spooky happening, an attack is um is
shown or implied, and then it's daylight and cops are
discovering a body and their crabs on it. I can
think of two examples. One is in Joy Laws after
the initial tack attack at the beginning, when they discover
the body of the first victim on the beach, their
crabs everywhere, and it makes the police sound sick. Um.

(24:09):
Second one is an even better movie. It is I
Know What You Did Last Summer, in which there's a
part where the nineties teen slasher movie where Jennifer Lovehwood
finds a body in the trunk of her car. She
did not put it there. I think she's being messed
with by a killer and it's covered in crabs that
are presumably scavenging it. So yeah, and I think there

(24:31):
are various other films. I thought I've seen a Jellow
film where they're there there crabs on a body. It's
just it makes sense. They're discovering a body, put some
crabs on it, um and uh, and it'll make it
a little a little creepier um. And then it it.
You know, it does, because it's like this person is
not only dead, but now they are the domain of
the crabs. Um. So in thinking about this, though, it

(24:52):
reminded me of a bit of Um. I guess it's
folk wisdom that I learned from my mother in law, uh,
and that is, don't eat crabs after hurricane. Have you
ever heard this before, Joe? I think maybe you and
I have talked about this off Mike, maybe, Okay, because

(25:13):
I was. I was looking around for more on this online,
and I found some sort of echoes of it, but
I did not find enough on it that made me
satisfied that this is not something that just originated with
my mother in law or her family, or like, you know,
a local area that like her parents were in or something.

(25:34):
But I'll continue to discuss it here and certainly if
anyone out there has heard the same thing or is
privy to the same folk wisdom and has some insight
into why it is, uh, well, obviously we would love
to hear from you. But the notion here seems to be,
uh that, Okay, those crabs in the wake of a hurricane,
they have been feasting on the flesh of people who

(25:56):
died in the storm, and therefore they should be avoided.
I can understand that. Yeah, yeah, I mean it's I
guess a lot of it comes down to the idea
that if these crabs have been eating humans and we
eat those crabs, it's kind of cannibalism by proxy, right, Yeah,
And generally we don't eat like a lot of even

(26:16):
if we're eating meat, we're not eating carnivores, or we're
not eating animals that are that are eating a lot
of meat. We tend to consume herbivores. Yeah. Well, I
mean if you're eating seafoods, you're probably eating a lot
of cars. Well yes, yes, the seafood for sure. But yeah,
but I also I did find some just looking around,
I saw some people like asking and some of these
like question websites saying is it okay to eat? Like

(26:38):
they were kind of applying the same concern to just
see life in general, like should I be concerned that
the fish that I'm eating might have themselves eating human flesh?
Well that's a sticky idea, they'll get in your head. Yeah. Yeah.
So I decided to look into it a bit more.
And I was looking. First of all, I was looking
at a few different sources in uh. They included Coastal

(26:59):
Angler magazine and also additions of the Sun Sentinel. Um.
And so it's worth remembering that hurricanes are destructive not
only the humans and human civilization, but they also impact
marine environments. This can result in extra dead sea life
in the water, and that includes crabs. And this can
often be due to um reduced dissolved oxygen in the water,

(27:20):
rapid salinity changes, and violence surf. And this can certainly
impact crabbing as a human enterprise, either by damaging the
equipment that's necessary for crabbing or disrupting key crabbing locations.
And this applies to other organisms as well. Um. It
can you know, be especially rough on oyster seed grounds
for instance. And as far as oysters go, the other

(27:43):
key issues related to hurricanes and other storms is flood
runoff from the mainland carrying various chemicals into their environment.
And as oysters or filter feeders, they can pick up
those chemicals um and that can then be composed a
danger to human means consuming those oysters. Uh. And of
course there are other potential risks involved with eating raw

(28:05):
shellfish as well, But as far as I can tell,
this doesn't really impact crabs so much. Um. But I
wanted to look a little bit more about the you know,
the idea of of corpse eating crabs First of all,
I wanted to sort of check my my assumptions on
this and and find out, well it is as true
or am I just sort of learning this from movies?
Do crabs want to eat human bodies? Um? And And

(28:27):
luckily you know, there's a lot of material out there
in the world of forensics UM in biology UM, human
corps in water may be set upon by fish, water, rats, crabs, um,
various other creatures. According to UM. One paper was looking
at by zerin er Call and Urdum Hoskuler in post
mortem animal attacks on human corpses came out and so

(28:51):
this applies to shallow water as well as deep water,
where crabs will uh may even gnaw the bones that
they find down there. Wow, now apparently some crabs are
going to be more indiscriminate than others. So yeah, yes,
you know, we have to be careful we talk about
crabs because if there's not just one type of crab there,
they are multitude, and they all have different strategies and

(29:12):
different environments and different temperaments. UM. I believe blue crabs
in particular are often observed to scavenge human flesh band
and that probably has to do again with like environments
in which law enforcement or finding bodies and bodies are
retrieved and uh, and that's gonna happen to be the
same environment where the blue crabs are active. Another type

(29:35):
of crab that we've talked about on the show before,
the coconut crab. Uh. They seem to generally be game
for for anything. So it seems like a safe assumption
to say that, yes, you've you've given the opportunity. The
coconut crab would feast on human flesh as well, But
as for other species, I would say, check with your
local crab. I don't know if they want to eat
you or not. UM, And a lot of it's gonna

(29:56):
depend on are you where that crab is, what is
that crab normally and so forth. Now, I was also
looking at an article title Decomposition and Invertebrate Colonization of
Cadavers in Coastal marine Environments by GAYL. S Anderson from
two thousand and nine, and in this the author points
out that um in saltwater environments, crabs, crayfish, and barnacles

(30:19):
are generally the most important arthropods from a forensics point
of view, and they point out that crabs, especially we'll
we'll just get right in there. They'll go for the
facial flesh and the eyes, the open orifices of the
face are I mean, just think about this practically, Joe,
don't to like, if you're gonna start munching on a human, Uh,

(30:40):
all those holes in the face, that's just a great
place to get started, you know. Yeah, that's the that's
like the oysters on a chicken. Yeah, so that's that's
generally where they start. But once they get going, apparently
they can rapidly d flesh a body. Um. I was
looking around to see if I could find some hard
numbers on that because I know a lot of times
it is of key interest in forensics. Um, you know, Okay,

(31:03):
animals will do this to a body, Scavengers will do
this to a body. How long does it take for
them to do it? Because then we can time the
you know, the death of of this particular individual, or
we can time when their body entered this environment. I
could not find any any time. That doesn't mean they're
not out there. So if you know those, if you
haven't to have like a you know, some sort of

(31:24):
study that involves a stop watch, a human cadaver and
a whole bunch of blue crabs, then send it my way.
I would look to take a look at it. Do
your personal eco friendly funeral plans involve crabs crab burial?
I mean, why not? Why not? So I want to
come back to the question. Okay, uh So, First of all, okay,
I think we can say it's safe to say that

(31:45):
crabs definitely will de flesh the human form um. Now,
as for this idea of there being something bad about
eating those crabs after they have tasted human flesh, um, again,
I think there is a sort of superstitious view there,
and there's perhaps this you know, revulsion of the idea

(32:06):
that you might eat something that has eaten people, and
then you know, to some extent you are engaging in
cannibalism by proxy. Now, where this gets interesting, though, is
when you start looking at the subject of cholera and crabs. Um, Joe,
had you ever uh were you privy did any of
this information before? No? I mean cholera And I know
cholera is typically a water borne illness that has spread

(32:28):
through contamination of water sources by infected people. Yeah, yeah,
and uh, and so when you think about cholera, you
tend to think about. You didn't think about a sewage.
You think about you know, you know, poor water treatment,
water sources, that sort of thing. UM. But apparently crabs
and UH and some other shellfish can also UH be

(32:51):
a means of acquiring cholera. Now as and I was
looking around him mostly mostly when we're talking about this,
we're talking about UH some some particular situations. And there
have been particular outbreaks that have been linked to the
consumption of crabs that that are infected with cholera um,
or at least they have cholera like clinging to the bacterium,

(33:15):
clinging to their their shells, UH, to the hard parts
of their body. For instance, there was an outbreak in
nine in coastal Louisiana and it was blamed on improper
storage or cooking of crab the crab and the crab
and in questions seem to have have you know, the
cholera bacterium clinging to it. Apparently there was a similar

(33:37):
case in Texas UH previous decades. I was able to
find some news footage from the late seventies from like
from Louisiana Public television where they were talking about this UH,
and it was quite interesting because you know, it was
it was a big deal. There were a lot of
questions like, Okay, what's happening here, Why did these crabs
have cholera? Why are people you know, what's going on?

(33:59):
And then there was concern over how is it gonna
impact the crabbing industry and just people's lives in general. Um,
and uh, yeah, it was quite interesting because you know,
to be clear, cholera is generally we think about it
as a as a human situation. You know, this is
where you you find the cholera. Cholra are pathogenic to humans. UM,

(34:22):
So they're not actually you know, infecting uh, the crustaceans
in question here, but it would be a situation of
them being in waters infected uh, that that are tainted
by cholera or potentially and this seems to be like
a less firm point. It seems like potentially if you
had these crabs coming in contact with the bodies of

(34:45):
humans that had cholera, they could partitually get it that way.
But it seems like for the most part we're talking
about just water that is say, tainted by untreated sewage,
and and you have people in the population that had
cholera contributing to said sewage. I see, So it seems
like moral of the story is definitely properly cook your

(35:05):
your your seafood. Yes, definitely, that's that's that's a proper storage,
proper cooking. Um. And that seemed to be the main
point they were getting to in this situation. I believe
based on some of the follow up information was looking
at from the CDC, it seems like this had to
do with UM with with the with pollution of the water,

(35:26):
either due to some sort of a sewage situation, sewage treatment,
or sewage run off from something else, potentially something linked
to U two ships UM but um. Looking also at
the CDC, they point out, quote, brackish and marine waters
are the natural environment for the ideologic agents of cholera

(35:47):
H Vibrio colorad UH zero group zero one or zero
one three nine. There are no known animal hosts for
Vibrio colorade. However, the bacteria attached themselves easily to chitten
containing shells of crabs, shrimps, and other shellfish, which can
be a source for human infections when eating raw or undercooked. Now,

(36:10):
I know what you're saying. You're you're probably thinking to yourself, well,
that still doesn't answer the question can can Does that
mean you can catch cholera from a crab that eighty
human being with coolera? I'm still I'm still not sure.
I don't but but I don't think any of the
evidence is pointing to that being like the primary way
that you would get sick from, uh, you know, for
meeting a crab, or that has anything to do with

(36:32):
with concerns over eating crabs post hurricane. So I'm not sure.
I'm not sure. I can't ask my mother in law
anymore about this, but I have this suspicion that perhaps
it's kind of a kind of like a Cajun stew
of like maybe a little bit of folklore in there.
Also maybe a little bit uh, left over stemming from

(36:52):
this late seventies um, you know, fear about cholera and
the crabs. Uh, and you know, perhaps some other stuff
to on in there as well, um uh. And also
maybe she was just you know, messing with me. Yeah nothing.
Maybe that's familiar with the ways of the of coastal
Louisiana and so forth. Well, I mean, I would say,
whatever the base of this, uh, this piece of advice

(37:15):
or folk wisdom is, I would say that it's probably
always going to be different. I mean, unless you're in
some kind of like farmed bond villain scenario, it's always
going to be difficult to know whether or not a
crab that you have actually acquired to eat like what
it has been eating in its past. Yeah. I mean,
you just never really know if it had eaten a

(37:36):
part of a human or not. But the odds are
probably against it. Yeah. Yeah. And um, and in terms
of other crab and just crabs in general, like eating humans,
like another area to get into as well, would a
crab kill a human and eat it? And uh, this
does come up from time to time. I think there
was you know, largely you know, unproven and to a
certain extent at least discredited theory that coconut crabs consume

(38:00):
to aviator Amelia Earhart, or at least consumed her remains
after she crashed. Um. Again, I don't think there's any
proof for this, and and I don't know that anyone
is actually arguing that the crab crabs would have killed her,
but um uh, you you know, it's one of those
things where you can make any kind of argument for Okay,
what if somebody was sufficiently injured and then crabs came

(38:22):
upon them. Could the crabs deal the killing blow? Could
the crabs be the one to finish you off? And
I guess it's like with the dinosaurs, like could have
Could crabs kill a dinosaur? Well, I guess so if
they had enough of an advantage, uh, you know, if
the if the prey was severely weakened. Um, But I

(38:42):
don't know. It seems kind of pointless to to worry
about this too much. I mean not to be insulting,
but a crab is not really a particularly analytical creature,
so I don't think it could size us up and
figure out what part of the body it needed to
attack in order to finish us off. We are not
part of a crab abs like natural uh you know,

(39:03):
habituated diet, so I don't think it would have instincts
about what part of the body to attack to finish
us off. So I would say, if a crab attacks
the human is probably just randomly pinching at whatever parts
of the body it can get at. So my guess
would be that it would be very unlikely for even
the most powerful crabs, even your coconut crabs, to to
really initiate a successful deadly attack on a human. But

(39:27):
there is something about maybe it comes back to that
defensive display of the crab. It's so impressive, even though
it's small, uh, that it just reverberates through the human
psyche and takes on the form of say, crabs attacking
hercules and myth or crabs rising up against humanity in
Roger Corman films. And so we just get it just

(39:49):
shows how effective that display is. We're like, we we
know that crabs not actually gonna come over here and
and and whoop us uh, but but it takes on these, uh,
these enormous forms in our mind mind right, I mean,
the the rasp of the gastric mill does not lie.
There's no reason to go messing around with that thing,
putting your fingers into its pinchers and stuff. But I

(40:09):
am generally curious though, So if anyone out there again,
if you've heard anything about this, um, this bit of
a folk wisdom that you shouldn't eat crabs after a hurricane,
or that eating crabs that of eating humans is is
is somehow specifically a bad idea. Uh, fill me in.
I would love to know more before we move on.
I just wanted to say about the coconut crabs thing.

(40:30):
I had also come across that people supposedly claiming that
that Amelia Earhart was eaten by coconut crabs, really without
any evidence to say that. I think people were just
kind of guessing, oh, what if this happened. Um. But
but that did make me think back on on Charles
Darwin's comments about how coconut crabs actually being delicious and

(40:51):
under their tails having that big mass of fat which
turned into wonderful limpid oil. Remember that, Oh yes, I
do remember that. Yeah, you know, this reminds me was
I was looking around, um, you know, doing various searches
on fatalities related to coconut crabs, and I did find, um,
I think a couple that occurred. Uh. And but they
didn't have anything to do with crabs attacking people. They

(41:12):
had to do with the coconut crabs haven't eaten something
that contained a toxin and then when that crab was
consumed by humans resulted in fatality. Oh, that would make sense.
So I think, oh, yeah, ultimately crabs dupos the greatest
risk to human beings in the form of you know,
of of tainted food, of one sort or another, but

(41:33):
that can be that can be said for a lot
of things. It's as with our past Thanksgiving episodes on
dangerous foods. Um, you know, any kind of if food
is cooked improperly or stored improperly, prepared improperly. Um, you know,
it's it's pretty easy to get into dangerous zone. Oh yeah,
I mean one of the points we made repeatedly in
that series is if you're actually just like tallying up

(41:56):
edge cases, all kinds of strange things can seem very dangerous.
You know, Uh, improperly washed, packaged greens, bottles of peanut
butter and all kinds of stuff. Yeah, I mean, I'll
go ahead and throw this out there. Don't try and
eat um a live crab hole. I think you're probably
going to hurt yourself. May have to go to the
hut of the hospital over that. Yeah, don't go for

(42:18):
the had restore Crudeau. Yeah, alright. The next example of
the next course in the crab Feast I wanted to
talk about is, uh, maybe the I can't remember for sure.
This may have been the thing I was reading about

(42:38):
that gave me the idea to do this episode. Um,
And this is one where you can actually watch the
video I'm about to talk about yourself, because the subject
here is a field recording that was uploaded by the
Monterey Bay Aquarium Research Institute or in Bari, originally captured
in two thousand eleven. You can find it on their

(42:59):
YouTube channel now. And this took place on an expedition
led by a researcher named Peter Brewer. So the team
here was investigating oil seeps and methane hydrates along the
seafloor off the coast of British Columbia. Again, this was
back in two thousand eleven, so this would have been
on in the ocean off the west coast of Canada.

(43:22):
And methane hydrates are a very strange and fascinating phenomenon.
I again didn't know a lot about them before I
started researching for this episode, and this has really captured
my mind. So these are essentially chunks of solid icy
material containing large amounts of methane alongside regular water molecules.

(43:45):
So it's got methane gas or H four, which is
a naturally forming hydro hydrocarbon. Methane is the primary constituent
of so called natural gas, as well as being a
byproduct of bacterial decomposition of organic matter that gets buried
down in the sediment at the bottom of the ocean,
and pockets of natural gas underneath the modern sea floor,

(44:08):
or just generally any methane content in the sediment or
the or the bedrock below the ocean. Sometimes the methane
in these pockets get exposed so that gas can escape
up through little holes or rifts in the in the
sea floor and float away. But sometimes, under the right conditions,
methane that escapes from these pockets does not just float away. Sometimes,

(44:32):
because of very high pressure at the bottom of the
water column and extreme cold in the deep ocean, the
methane gas becomes trapped along with water ice in chunks
of this strange frozen solid. These are methane hydrates, and
to be clear, the name is a little bit misleading

(44:53):
because methane hydrates are actually not a new chemical compound
joining water molecules and methane molecules with chemical bonds. Rather,
methane hydrates are what's known in chemistry technically as a
class rate, which is a composite in which you've got
molecules of one kind of substance. In this case, methane

(45:14):
that are physically trapped within the crystal structure of another
type of substance, in this case water ice, so little
molecules of methane stuck within a lattice structure of water ice.
And because of this unusual structure, methane hydrates can make
a literally flammable ice. So you can have a big

(45:35):
chunk of this stuff. It looked pretty much like regular ice.
You can set it in a dish on a table,
but if you hold a match up to it, this
is ice which will catch on fire and burn. And
for this reason, methane hydrates are sometimes called fire ice.
Now it's generally believed today that large amounts of solid
methane hydrates lie buried in formations underneath the sea floor

(46:00):
all around the world, though there's debate about exactly how much.
According to a range I found given on a page
by the U S Department of Energy, Fossil Energy and
Carbon Management site, there could be anywhere from two hundred
and fifty thousand trillion cubic feet of methane locked up
in hydrates around the world, from that two hundred fifty

(46:22):
all the way up to seven hundred thousand trillion cubic feet,
and these hydrates contain a really dense concentration of hydrocarbons.
A claim I've seen cited in a number of sources
is that one cubic meter of methane hydrate would typically
contain a hundred and sixty four cubic meters of methane gas,

(46:44):
So a very small volume of this solid material, this
icy stuff, the hydrate, if disrupted, will potentially release a
ton of gas, which, of course is one reason that
methane hydrates have people who think about climate change a
little bit can cerned, because it seems that there is
actually a significant amount of potential greenhouse gases that could

(47:06):
be released into the atmosphere locked up in these solid
icy forms, and if something causes these solids to melt,
a lot more stuff can be released into the atmosphere.
But anyway, so these methane hydrates exist in these you know,
rocky icy formations under the sea floor, but they can
also form spontaneously when methane and very cold water mix

(47:29):
under high pressure, like at the bottom of the ocean.
So coming back to this video, I was talking about
the video captured by the Monterey Bay Aquarium Research Institute
team in two thousand eleven. So they were doing a
survey for of these methane hydrates and oil seeps at
a depth of about one thousand, two hundred and sixty meters,
and the team came across a rift in the sea

(47:52):
floor that was producing this steady little trickle of bubbles
rising towards the surface. And while the researchers were looking
at the stream of bubbles, suddenly, hey, here comes a crab.
It just there's a crab coming into frame, and the
narrator of the video suggests that the crab may have
been attracted by the pulsing in the water column at

(48:14):
the side of the gas bend. But whatever the reason,
this crab comes ambling over. It's walking along the bottom,
and then it comes right up to the hole in
the ocean floor that the bubbles are coming out of.
And then, in the first of a series of real
awe buddy moments, it reaches out at the stream of
bubbles with its claws. It's trying to grab them, very

(48:37):
like you know, dog dog chasing its tail behavior. Presumably
it thinks that the movement in the water indicates some
kind of potential prey or other food source, and you
see it repeatedly lunge at the bubble tower with its claws,
but of course there's nothing to grab, so it just
sort of hugs the bubble jet several times. But then

(48:58):
from here things start geting weirder, because again, what are
these bubbles their methane and what can potentially happen to
methane at this depth and temperature When mixed with water,
it can turn into methane hydrates. So the narrator of
this video explains that the methane gas bubbles rapidly form
into solid pieces of methane hydrate as they stick to

(49:19):
the crabs for limbs, so it's you know, reaching out
to grab the methane bubbles. It thinks their food. Then
they the bubbles are freezing into a coating of fire
ice on this crabs clause and then trying to explain
what happens next, the narrator of this video hypothesizes that
the chemical reaction that transforms the methane gas into these

(49:42):
solid chunks of methane hydrate uh quote may have given
the sensation of something slightly warm and mushy. Uh So,
I guess this is just supposition on on the researchers part.
But maybe what they're suggesting here is that the crab thing, oh,
I've got some kind of potentially delicious organic goo, maybe

(50:04):
from a dead whale carcass or something, and it's all
over my claws. Now, so of course, when in doubt
try it out, you know, better eat it and see
if it's good. So the crab begins to try to
eat the methane hydrate off of its own claws, and
this goes very poorly because the hydrate essentially freezes the
crabs mouth parts or mandibles, which reminds me of that

(50:27):
thing where you know, you stick your tongue to a
frozen flagpole, like in that Christmas movie, except I guess
here the flagpole would be like stuck to your own
mouth and it would be coming along with you. And
the narrator of the video actually describes it as quote
a milk mustache of solid hydrate. Well, now I'm beginning
I'm growing worried for this crab. This that is that

(50:47):
this has really taken a turn. I know, it went
from like kind of cute and bumbling to like, oh no,
what's going to happen to this crab's mouth? Uh? And
apparently the crab does whatever it's feeling. It does not
like it at all, So it starts it's trying to
use its claws to remove the frozen methane coating from
its mouth, and you can see it's scraping at the
solid white mass of hydrate with the tips of its

(51:10):
of its claws while shedding flakes of it into the
surrounding water. And unfortunately, I do not know the answer
to the question did the crab ever get its mouth
on frozen I I hope so, but the researchers do
not have an answer to offer on this subject. On
the pessimistic side, the narrator claims that pure methane hydrate

(51:32):
is twenty times harder than regular water ice, though I
couldn't find independent corroboration of that fact. But on the
plus side, that like you can see in the video
that the crab is doing a decent job scraping pieces
of it off, Like you can see the flakes just
coming off and floating up into the water. So I'm
gonna say with crabs, many things are possible, maybe all

(51:52):
things are possible. And I'm gonna say that it really
just it. It scraped and scraped and scraped with those uh,
those spiny tips until until it got its mouth parts
free and went on to di scavenge many a human corpse.
But anyway, I mean, so this is on top of
being just a strange and interesting example of a crab
eating something that was not food, because you know, I

(52:15):
think anybody who has a dog will recognize that a
lot of animals have the impulse of like if if
something is ambiguously presenting as maybe food, might as well
put it in the mouth and give it a try.
But on top of that, it also shows an interesting
thing that we don't usually think about being land levers,
which is the role of naturally forming hydrocarbons as a

(52:38):
part of the environment that animals would have to interact
with every day. You know, on on the sea floor,
there were actually all kinds of ways that organisms regularly
interact with I don't know what you might call you know,
the constituents of the deep earth, uh, from from the
ecosystems that form around hydrothermal vents to these weird interactions

(53:00):
between animals and methane hydrates from under the under the
ground or under the sea floor. Obviously, for the crab
in this video, this was at least a very uh
frustrating and unfortunate random encounter. But some animals actually have
a much closer and more dedicated evolutionary relationship with these

(53:20):
same substances. With deep sea hydrates gas hydrates like methane hydrate,
they're actually marine biological communities that appear in some way
to depend on methane hydrates for their energy needs. And
just one example I wanted to mention I found described
in a paper from published in the year two thousand

(53:42):
and uh nat your viscin sho often um by a
cr fisher at all called methane ice worms hesio ska
methanicicola colonizing fossil fuel reserves and rob, I've got an
image for you to look at while I described this here.
But so in this case, the story behind this discovery
was that a bunch of researchers were conducting an exploratory

(54:05):
dive with a miniature submarine in the Gulf of Mexico
along the sea floor at a depth of fivetys. I
guess this was in the late nineties sometime, and they
came across a large gas hydrate, a chunk of this stuff,
the fire ice that was They said about one meter
thick and two meters in diameter, and they said it

(54:26):
had recently breached the sea floor. So I guess this
has been this had been some subsurface for a long time,
and for some reason it had recently been you know,
berthed up from the bottom of the ocean and was
now exposed. And this was a big, old chunk of
this stuff. And then the authors write in their abstract
quote two distinct color bands of hydrate were present in

(54:48):
the same mound, and the entire exposed surface of the
hydrate was infested with two to four centimeter long worms,
since described as an new species, and they said the
density of the worms reached individuals for every square meter.
So this was a previously unknown type of polycyte worm

(55:12):
that appeared to make a habitat out of these gas hydrates.
It was originally called uh hesio ska methanic cola. I
think now it has a different name. I think now
the genus is uh sears so s i r s
o e so sears so methanic cola uh So. This
would obviously raise the question, if you live around gas

(55:33):
hydrates at the bottom of the ocean, what do you eat?
How do you make a living well. Tissue samples were
consistent with the worms acquiring nutrition from a chemo autotrophic organism.
That would mean an organism that makes its own energy
by consuming geologic chemicals rather than than by sunlight like

(55:54):
a photosynthetic organism would. And the authors in this study
weren't able to prove anything conclusive Lee, but they hypothesized
that these worms, these new worms, were surviving by eating
chemosynthetic bacteria that colonized the surface of the gas hydrates.
So there would be bacteria that that form mats on
the surface of these frozen methane hydrates that would metabolize

(56:18):
chemicals contained within them in order for the bacteria to survive,
and then the worms would eat the bacterial mats. And
then the author's right quote, the activities of the polykeets
grazing on the hydrate bacteria and supplying oxygen to their
habitats appears to contribute to the dissolution of hydrates in
surface sediments. So I guess this would be one thing

(56:40):
that explains how these hydrates disappear over time once they're
exposed on the bottom of the ocean. But rob I've
also attached to an image for you to look at.
That's uh, I believe this is a micrograph close up
of the face of one of these polykeet worms that
lives on the hydrate. It is absolutely terrifying. It looks
like some sort of a dark destroyer unleashed from a shadows.

(57:04):
It has a kind of bristling fuzziness, which you would
think would make it a little more cuddly, but actually
makes it worse. Yeah, though those fibers are not for cuddling,
you can tell. And it looks like it has this
enormous mouth to like just suck down dreams. Very very true.
And yeah, it's mouth, I would say it's mouth actually
looks like if you ever see those um endoscopic images

(57:25):
of of the larynx or the voice box. Yeah, it
also reminds me it has the mouth of some of
the more terrifying muppets. I think you know where their
mouth is kind of articulated bad, Yes, like the the
hippiup aliens that has that kind of thing going on.
Oh god, the Hippiepps are so evil. All right, Well,

(57:45):
I think we're gonna have to call it right there
for part one, but we will definitely be back next
time to continue the crab feast. What will happen when
crabs put other things in their mouths while their mouths freeze?
Will they find it delicious? Um? You'll just have to
tune in to find out. The world is a buffet
and the customers or crabs all right? Uh? In the meantime, yes,

(58:09):
certainly right in let us know where your thoughts are
in the crabs that we discussed in this episode. Um.
But in the meantime you can find other episodes of
Stuff to Blow your Mind in the Stuff to Blow
Your Mind podcast feed which you will find wherever you
get your podcasts. On Tuesdays and Thursdays we have core
episodes of Stuff to Blow your Mind. On Monday's we
have listener mail, On Wednesdays we have artifact episodes, and

(58:32):
on Friday we have Weird How Cinema. That's our time
to set aside most serious concerns and talk about a
weird movie. Huge thanks as always to our wonderful 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, just
to say hello, you can email us at contact at
Stuff to Blow Your Mind dot com Stuff to Blow

(59:00):
Your Mind is production of I heart Radio. For more
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