May 17, 2025 • 58 mins
In this classic episode of Stuff to Blow Your Mind, Robert and Joe discuss the weird and wonderful parrotfish: changers of sex, poopers of sand and – if the myths and legends are true – great friends and a parent of fishes. (originally published 5/21/2024)
See omnystudio.com/listener for privacy information.
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:06):
Hey, you welcome to Stuff to Blow your Mind. This
is Robert Lamb. Today's Saturday, so of course we have
a vault episode for you. This is going to be
the Parrotfish Part one. It originally published five twenty one,
twenty twenty four. I hope you enjoy.
Speaker 2 (00:21):
Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Speaker 1 (00:31):
Hey you welcome to Stuff to Blow your Mind.
Speaker 3 (00:33):
My name is Robert Lamb and I am Joe McCormick.
And today on the podcast we're going to be beginning
a look at parrotfish or parrotfishes. This is one of
those topics that literally just started with me looking at
a picture. I was staring at a picture of a
bizarre goofy, goofy appearing animal and thinking I want to
(00:56):
know more about this critter, and then discovering that indeed,
this organ is a is a peculiar and fascinating story,
and there is so much more to it than you
might guess just by looking at it at its strange
beak or toothy mouth.
Speaker 1 (01:10):
Yeah, parrotfish are pretty fascinating. I've snorkeled among the parrotfish
many times and can attest that they're curious looking fish.
They're pleasure to watch. They're often very colorful. So I'm
going to throw in more of my observations as we proceed.
But I think, on the other hand, in coral reef environments,
(01:31):
where I've done most of my snorkeling, and where a
lot of snorkeling takes place, they can actually be easy
to take for granted because they're generally around and you
know significant numbers that these environments. Often these are protected
reefs that I've been to, they're not particularly shy, they're
easily found in shallow water, so you know, oftentimes you're
(01:52):
dealing with like reef environments that are either very accessible
just from the shore or just a very short boat
ride sort of a situation. So in a way, it's
easy to take them for granted because they're there, you
see them, and then you end up focusing a lot
more of your attention looking for some of the harder
to find organisms that are going to live in these
(02:12):
reef environments. So it's actually a great opportunity to stop
and focus on this remarkable fish that I honestly had
never really thought about devoting a whole episode or series
of episodes too. But there's more than enough to talk about.
Speaker 3 (02:25):
I've never snorkeled and seen them in person, so I'm
envious of this experience and maybe I will someday. I
look forward to that. But I've seen video and in
some cases that there's almost a feeling of like bees
buzzing around a shrub that's covered in flowers. You know,
it's just kind of the general gentle grazing activity of
(02:45):
some animals surrounding a plant like structure, but in this
case it's of the big skeleton of stony corals.
Speaker 1 (02:53):
Yeah, the grazing observation is key, and it's something that
has long been observed for these creatures, as we'll discuss
going back into ancient times, even when we didn't have
snorkelers as we think of them today, you still had
individuals fishing in shallow environments, sometimes fishing for the parrotfish
in question, and observing that, Hey, these creatures appear to
(03:15):
be grazing, unlike most of the fish that we are observing.
Speaker 3 (03:20):
So parrotfish are not one species, but a larger group
of fish containing about ninety something individual species. I've seen
different estimates on the numbers. I think it's older ones
that say, maybe like eighty species. Others say closer to
one hundred, but I think ninety something is about right.
They range broadly in terms of size and appearance. In fact,
(03:42):
they range broadly in terms of appearance even within a species,
as we'll get to maybe in this part or maybe later,
but some adult parrotfish are less than a foot in length,
and some of the largest are almost four feet or
about one point two meters in length, so they can
range from medium small to quite large. These fish are
sometimes taxonomized as a family called scarid and in other
(04:06):
cases regarded as a subfamily of Labridy, which are commonly
known as the rasses. I think you can see some
morphological similarities with the fish called rasses, kind of the
way they swim, the way they use their pectoral fins,
and stuff like that. But a characteristic come into many
parrotfishes is that they tend to live around coral reefs,
(04:27):
especially in the tropics.
Speaker 1 (04:29):
I also want to throw in there that there are
occasionally fish that are just sort of commonly called a
parrotfish or informally called a parrotfish, that are not parrotfish,
mainly the blood red parrot chick lid, which apparently is
a popular aquarium species.
Speaker 3 (04:45):
This is not.
Speaker 1 (04:45):
Actually related to proper parrotfish that we're going to be
talking about here today. And I've also seen some some
fossil evidence that is sometimes categorized as a parrotfish in
a way that I'm not sure actually lines up with
what we're talking about here. But if you've seen a
picture of a parrotfish proper parrotfish, indeed, go ahead and
(05:06):
look one up if you're in a position to do so.
I think it's hard to miss what we're talking about.
These are very recognizable fish, though again they do very
greatly in coloration.
Speaker 3 (05:17):
Size, that's right. Yeah, So if you look up pictures
of them, you'll see that they're often kind of elongated
in body. They have different shapes. Some are more kind
of that elongated oval shape and others are blunter in
the front with like blunt heads. They're in fact, our
parrotfish called like the blunt head pair of parrotfish or
the steep head parrotfish. The coloration you'll see on them
(05:40):
depends on some facts about them and not just their species,
but sometimes they have quite bright patterns of almost neon color,
surprising colors to see in nature. Very you know, tropical
kind of color signals. There's one picture I kept seeing
where the fish had a color pattern that reminded me
of the as design from paper cups in the nineties.
(06:02):
But if you also threw some hot pink in there.
So there's a lot to take in when you look
at look at a parrot fish. But before you notice
any of that, but you know, the head shape, the
body shape, the coloration patterns, what you will probably notice
first about any given parrotfish is the mouth. I mean,
look at these chompers. Rob I've included just several pictures.
(06:24):
I know you've seen them in person, so your experience
of the teeth the beak is probably more direct and
visceral and profound even than mine. But I was just
looking at these pictures for quite a while the other day,
and my God, that these beaks, these mouths, it's it's incredible.
Speaker 1 (06:41):
Yeah, Yeah, their mouths are quite fascinating in some of
the photos. Yeah, they can actually look a little intimidating, though,
I would say based on the species that I've primarily
been exposed to in Hawaii and the Caribbean, they tend
to look more silly then than threatening. But they're definitely
(07:02):
very cool looking, not taking anything away from that.
Speaker 3 (07:05):
Yeah, So I guess it varies from species to species.
So parrotfish have these rows of fused teeth on the
outside of their jaws, which, in some cases, as the
name implies, look very similar to the beak of a parrot.
It can look like a bird's beak, But in other cases,
these fused rows of teeth look like jagged monster jaws,
(07:27):
sort of like a horseshoe shaped ceramic saw blade. But
in other cases still they are like a big goofy
cartoon overbite, like Alfred Y Newman's mouth got hit with
the radiation from the amazing Colossal Man.
Speaker 1 (07:43):
Now I want to throw in one more note here
about species classifications coloration. It is worth noting that with
parrotfish that classifications in naming have long proof challenging because
they tend to show different colorizations depending on an individual's
age and sex. So, for example, was pointed out by
the Waikiki Aquarium, the spectacled parrotfish is reddish brown when
(08:08):
it's a juvenile, then it develops a pale tail spot
when it becomes a reproductive female, and then develops bright
blue green coloration. With pink markings when it becomes male.
So you can imagine a lot of the early confusion
at figuring out, well, what is a different species of parrotfish,
and you will have multiple species of parrotfish in a
given region, and then what is just parrotfish are the
(08:31):
same species that's just in a different phase of its
life cycle.
Speaker 3 (08:34):
That's right. In fact, I was even reading like some
blog posts by marine biologists who had worked with these
animals firsthand, talking about just how difficult it was sometimes
to identify these fish because of all the variation even
within species. But to come back to the main attraction,
the teeth, the beaks. The crazy thing is, as much
(08:56):
as these look like biting teeth in some cases, in
reality they are scraping teeth. Because parrotfish are primarily herbivores
for the most part, they do not eat by swimming
around biting semi circular chunks out of other fish, as
you might imagine just looking at their mouths. They mostly
(09:16):
eat by grazing along the hard surfaces of coral reefs,
scraping away algae and soft bits of coral and other
bits of organic matter, along with some hard bits of
the coral skeletons with their teeth, So that's what the
teeth are for. These are for grazing. These are the
(09:37):
life of a herbivore, not the life of a predator.
Speaker 1 (09:40):
Now, of course, as this we'll be discussing here. Coral,
of course is hard matter. And one of the crazy
things about snorkeling with parrotfish is that you don't just
get to watch them, you get to listen to them.
So as they feast on the algae that's growing on
the coral, they're scraping the coral, and it's producing a
sound in the snorkeler's ear that I would compare to
(10:02):
kind of a static paper crunching or even the snap
crackle crunch of rice crispies and milk. It's one of
those things when when you first explore. When I first
experienced it, I wasn't exactly sure what I was listening to,
because it's kind of like, oh, is there something in
my ears and it's just just the sound of the
ocean and so forth. But no, it it becomes clear,
(10:23):
and it's often pointed out to one that yeah, this
is the sound of these the parrotfish feeding, and yeah,
it's pretty remarkable. So you listen to them, you watch them,
and they just become part of the background sound escape
to your snortling.
Speaker 3 (10:38):
It's a funny other comparison to bees, almost, you know,
the way the buzzing of a bee just kind of
like blends in becomes the ambient sound of a landscape.
The tooth and beak scraping on coral sound produced by
these animals is maybe comparable to the buzzing of bees.
Speaker 1 (10:54):
Yeah, and it's also consistent, like that's the other thing.
They're constantly grazing, and therefore it is a constant soundtrack.
It's not like say, the occasional sound of a woodpecker
in a forest, Like it's just NonStop. So it's just
in the background, and you could easily if you didn't
know what you were listening to, you might not realize
that this is the sound of organisms feeding.
Speaker 3 (11:14):
Now, I think there are probably other people out there
like me, Rob, I don't know if you fall into
this category of people whose minds are easily captured and
revolted by just imagining kind of tooth trauma. Like I
very easily can like get a shiver across my whole
body when I imagine, say, trying to bite down on
a rock, And that is what you have to constantly
(11:37):
imagine when you're thinking about these animals. It's not technically
a rock, though I guess in some cases they do
scrape rocks as well, but most often it's going to
be like a rock. It will be the skeletons of
stony corals. But can you just imagine that, as painful
as it might be, imagine having to live by like seeing,
you know, a moss covered rock and thinking I'm going
(11:58):
to use my front teeth to scrape that bad boy clean,
and I'm going to bite off some chunks of the
rock as I'm getting the moss off of it. Delicious.
Speaker 1 (12:07):
Yeah, yeah, it can be a bit squeamish. It can
make one a bit squamish sometimes imagining these other dental
scenarios in the natural world.
Speaker 3 (12:16):
So I want to talk a bit more later about
how parrotfish eat and get their nutrition, and a bit
more about their teeth. But before we do that, Rob,
I think you've found some interesting stuff about writings on
parrotfish from the ancient world. Yeah.
Speaker 1 (12:29):
I did, And this was a whole avenue that I
had not been down. I had no idea this was
a thing. So again, given that species of parrotfish are
found around the world, and that they can frequently be
found in shallow water, and that they have traditionally been
caught for culinary purposes for food, it should come as
(12:52):
no surprise that these fish were known to people so
the ancient world, you know, even in times when folks
didn't have axe to the underwater world in any way
comparable to what we have today, they still knew what
these fish were, and in some cases they had some
rather insightful ideas about what they were doing. In other cases,
(13:13):
there are some very long standing misconceptions about what parrotfish do.
So in this we're going to actually bring up the
work of our dear old friend Roman historian Plenty of
the Elder, who is one of several sources of antiquity
that discusses the parrotfish, you know, and of course there's
a lot of shared content and so forth going on.
(13:35):
The fish would have been known as the scars. This
is of course, now where we get the name of
the genus for parrotfish, and we might assume that in
particular we're dealing with discussions of the Mediterranean parrotfish, though
based on what I was reading. Also, you had like
the red sea parrotfish that was also known to various
cultures of antiquity. So Plenty of the Elder in the
(13:58):
Natural History seventy nine CE rites at the present day
the first place, and this is he's speaking from a
culinary perspective here. First place at the Roman table is
given to the scars, the only fish that is said
to ruminate and to feed on grass and not on
other fish. It is most commonly found in the Carpathian Sea,
(14:21):
and never of its own accord passes lectum a promontory
of trois now. Nineteenth century naturalist George Cuvier and his
annotations to Plenty points out again that the first place
here is in reference to the Roman dinner table, where
this fish was celebrated for several attributed characteristics that I'll
(14:43):
get to in a minute, and was also typically quote
salted with the intestines in it. M okay, and some
Roman authors actually absolutely insisted that you do not eat
this fish without the intestines included. It's just too delicious
this way.
Speaker 3 (14:59):
Oh boy, So like, are you saying they would eat
the intestines directly or it's like you got to leave
the intestines in there to give them meat some flavor.
Speaker 1 (15:08):
You've got to leave them in. Yeah, okay, And I
know they were often in many cultures salted and then traded,
So I'm offhand, I'm not entirely sure if this is
a definite case of we're talking about salted parrotfish with
the intestines still in, or some other form of preparing them.
But at any right, they really liked it. There are
(15:28):
also Roman references to eating parrotfish livers as a delicacy.
Speaker 3 (15:33):
Mm so all the value here is just for their
flesh as food. This is a first place distinction that
would probably not be so flattering to the fish itself, right.
Speaker 1 (15:43):
Right, And the Romans weren't alone in appreciating eating parrotfishes.
We'll get to some other far flowing examples. Plenty of
humans have eaten parrotfish and still eat parrotfish. The Greeks
love them. There's some I think twenty species of Mediterranean parrotfish. Again,
there's the red sea parrotfish, considered a delicacy in antiquity,
(16:05):
And in both of these cases, I believe they were
often dried and then widely traded. I've read that in fact,
they were easily dried. I'm not sure about the particulars
of that, but I'll take their word on it that, Okay,
this is a fish that is easier to dry and
prepare and then trade across distances. You don't have to
eat it fresh by the seaside. Anyway, it was celebrated
(16:30):
at the Roman table, not just because you ate it
salted and with the guts in it, but also for
several reasons, according to Cuvier, and I think a lot
of these seem to get down to the fact that
I'm assuming the Romans liked a great story at the table.
You know, it's not just about what the fish smells like,
taste like, looks like on the plate, but also what
(16:51):
is the story of it, what ideas are wrapped up
in this particular organism. So here that first of all,
it was thought to be the only ruminating fish.
Speaker 3 (17:00):
So so wait, does that mean ruminating as in like
a like chewing the cud like a cow or a sheep.
Speaker 1 (17:07):
Yes, though basically I think what this comes down. First
of all, they're not truly chewing the cut. They're not
truly ruminating, you know, they're not chewing something that has
previously been chewed and swallowed. They are grazing like a cow.
And I think it has to do with observations of
these animals grazing, and it's like, oh, look they're they're
(17:29):
like a cow. They're ruminating. But still the idea that
they're ruminating, the idea that they're chewing their cut continues
to be mentioned all through antiquity on all the way
up through like medieval besty areas those some voices such
as Saint Ambrose in the fourth century said that did
point out the chud the cud chewing thing is not accurate,
(17:50):
that's not what they're doing. So but but still a
lot of misinformation about these fish persisted for a very
long time now. As Aristotle also observed in History of Animals,
the parrett fish were thought to be vegetarians, and indeed,
I guess you could say they're essentially herbivores. Many sources
(18:11):
will classify them as such, but also note that they're
maybe more more correct to say that they're algavores. But
still ancient people observe that these fish are not eating
in the same way that other fish are.
Speaker 3 (18:23):
Wow, this is something I feel like I should know.
The answer to, but I actually don't what is it called.
If you mostly eat you know, algae or plant things
that are like plants, plants, or types of bacteria microorganisms,
but sometimes you eat animals. But the animals are not
like you know, large moving animals, they're you know, basically
(18:45):
small invertebrate animals like corals.
Speaker 1 (18:48):
Yeah, I guess you would be some sort of a
coral war or something to that effect, right, But on
a number of the different fish databases that I was
looking at, yeah, sometimes they'll say herbivore, sometimes they'll say herbivore, algivore,
and then sometimes there's kind of an omnivore note as well.
I guess there's always a margin of error, as we've
discussed here, like even things like a cow, which we
(19:09):
think of is kind of a pure herbivore. There are examples,
as we've discussed on the show in the past, where
they have been observed to if meat is available, they
might eat set meat.
Speaker 3 (19:18):
But it is true that in the cases where parrotfish
are eating animals, they're not generally like chasing after other
fish and eating them or something. I don't know if
that might happen in some particular case but that's not
generally what parrotfish do. They're mostly going to be eating algae,
and then if they're eating animals, they're like marine invertebrate animals.
Speaker 1 (19:39):
Yeah, so I mean we can, I think basically say
that ancient people were correct in this judgment. Now, and
I guess maybe it made the story at the dinner
table a little more interesting. They're like, this is the
cow of the sea, that sort of thing. Now, the
third attribute that Kuvia mentions is quote because it had
the faculty of producing a sound. Now, perhaps I'm not
(20:03):
completely understanding Cuvier's point here, but I guess this is
referring to that constant chewing sound, that constant grazing sound
that one hears if your head is below water with
the fish. And again, this is not something that I
would think actually impacts one's enjoyment of dinner. But again,
I guess they liked a good story.
Speaker 3 (20:23):
You know, sometimes people they say they want their steak
rare by saying I want it still mooing. It's kind
a kind of a gruesome way to ask for it.
But people do say that. Can you say that, like,
I want my parrot fish steak rare? I want it
still scraping, I guess.
Speaker 1 (20:37):
So the fourth attribute that he mentions is quote for
its salacious propensities numbers being taken by means of a
female attached to a string. This, I guess alluding to
a supposed method of catching them. And I suppose the
Romans just like Randy food, though I'm not sure it
was actually considered an afrodisiac because I didn't see it
(20:57):
listed in another source I was looking at that had
to do with various foods of the Romans did believe
were aphrodisiacs.
Speaker 3 (21:03):
Uh huh okay.
Speaker 1 (21:05):
And then fifthly for its quote remarkable sagacity and affording
assistance to another when taken in the net.
Speaker 3 (21:13):
Huh, Now what would that mean?
Speaker 1 (21:15):
So this is referring to something that is that that
pops up in various old sources as well, and again
continues to persist for centuries. May be particularly referring to
a passage in Ovid. Ovid has the following passage quote,
(21:36):
the scas is caught by a stratagem beneath the waves,
and it length dreads the bait. Fraught with treachery, it
dares not strike the osers. This refers to a reed
basket with an effort of its head, but turning away
as it loosens the twigs with frequent blows of its tail,
it makes its passage and escapes safely into the deep. Moreover,
(21:58):
if perchance any kind scarus swimming behind sees it struggling
with the osures, he takes hold of its tail in
his mouth and it is thus turned away, and so
it makes its escape. So, okay, they have this idea
that these fish, these parrotfish, are essentially I don't think
(22:22):
you social would be the term, but they are. They
help each other out. They're capable of some form of
altruism where if they see another one of their kinds
stuck in one of these wicker basket traps, they will
try and help them out.
Speaker 3 (22:36):
Huh.
Speaker 1 (22:37):
And so this idea ends up sticking around for against
centuries and centuries. The idea that the scais or parrotfish
is not only a cud chewing herbivore of the sea,
but also a friendly fish that looks out for it's fellows.
Speaker 3 (22:50):
Well, that's fascinating, But I wonder what would this belief
about their like friendly behavior be based on. So the
idea is they help each other avoid traps, or say
each other from traps. Is there any modern research on this?
Speaker 1 (23:03):
So the main source I found on this, and this
is where I got turned onto the idea, it was
the blog of Fishtories. It's like histories and fish combined.
That's f I S H T O r I E
S dot net. It is a blog maintained by Sophia Hendricks,
an information scientist and historian of science. She discusses this
(23:24):
whole weird scenario with imagery of the parrotfish, because indeed
there's there's there's imagery associated. I included this illustration here
for you here Joe from a munch latter later source.
But but she does point out that based on what
we can tell, the fish are actually anything but friendly
to each other in these scenarios. Wicker baskets like this
(23:48):
are still used in some places to catch fish, she
points out. But she writes that the parrotfish have actually
been observed too violently attacked their fellow parrotfish that become
caught in the reeds of the fishing basket. So I
don't know that there's really much evidence to back this up.
(24:08):
I also get to an example here in a bit
involving traditional Hawaiian techniques for catching parrotfish that also uses
the basket, like the idea of being essentially that the
parrotfish are roaming around the corals feeding and they kind
of have these paths that they follow. They also tend
(24:28):
to sort of group together, and you may have what
seems to be a leader of the pack. And if
you set up these baskets at the right time, you
can catch them, and you can end up catching a
bunch of them even and you can then release the
ones you don't want, make use of the ones you
want to harvest. So I don't know. On one level,
it seems like, OK, you're ending up with an artificial
(24:50):
environment scenario here, where you're dealing essentially with captive fish
doing things in a captive environment and a high stakes
environment for them that they might not do otherwise, and
that may mean attacking each other that I guess could
also mean some sort of observational behavior, especially without the
aid of any kind of like snorkeling mask and so forth,
(25:12):
it might look like one's helping the others out. I'm
not sure, but still the idea becomes entrenched and the
image of the parrotfish helping each other escape from fishing
baskets ends up becoming a symbol of friendship. Oh yeah,
so this is something that she discusses at length in
another paper. This is something that published in Emblems of
(25:35):
the Natural World from twenty fifteen Ichthyology and Emblematics in
Conrad Gesner's Historia Piscium and Joham Kamarius's Kamarus the Youngers
Simbola at Emblemata. She points out that Plenty was one
of the key sources for this misconception, but plenty of
(25:56):
others sources in the ancient world echoed at Plutarch chimes
in on it, and so some sources identified this as
a sign of intelligence in the parrotfish, while other fishes
were often held up as examples of a lack of intelligence,
and fish, such as then Conrad Gessner's sixteenth century work
Historian Animalium, the mackerel was held up as a stupid fish.
Speaker 3 (26:18):
For example, how do you get that distinction as a fish?
Speaker 1 (26:22):
I don't know, I mean, maybe they just it's probably
a little bit unfair, right in some cases the macvil
looks to and you're basing everything on the human perspective
and human expectations of what an animal's intelligence is, you know,
whereas ultimately you can I think you can approach these
scenarios by saying, well, yeah, the parrotfish is in a
way a genius. It's as smart as it needs to
be to do the things that it does.
Speaker 3 (26:43):
Well. Actually, you know what, I wonder if some of
this I have no idea if it applies in this case,
but I wonder if some general ideas about smartfish versus
dumbfish come just from the experience of fishing for different
types of fish, because I know, you know, and people
who are into fishing right in and let us know
(27:04):
if this matches your experience. In my experience, people who
like to fish will like say that a fish that
is harder to catch is a smart fish, and one
that's easier to catches like a dumb fish. And I
don't know if intelligence actually has anything to do with
how easy they are to catch or not. You know,
might just have to do with like ingrained behavioral patterns,
(27:26):
someone responding distress or something.
Speaker 1 (27:29):
Yeah. Yeah, And it's kind of curious because it sounds
like if you have the right traps for it, catching
parrotfish is generally not considered super challenging. So but you know,
we have this other narrative that emerges again that they're
helping each other and that they can sort of help
each other escape from these traps and so forth. Now
(28:00):
I mentioned Hawaiian traditions because again, you know, you have
parrotfish all over and you do have them in the
Hawaiian Islands and in Hawaii. The parrotfish was historically known
in the Hawaiian language as uhu. The fish are prominent
there and they were eaten by Hawaiians. Traditionally. There's a
saying in Hawaiian, according to the online Hawaiian dictionary Ulucal,
(28:25):
that translates to my craving makes my mouth water for
the parrotfish passing before my eyes. The Hawaii Coral Reef
Network points out that not only were they a delicacy,
but their liver was especially favored. So again, you know,
you know, other side of the world, you still have
people eating parrotfish and also realizing that the liver is
apparently really good.
Speaker 3 (28:45):
Interesting.
Speaker 1 (28:46):
Now, the fish itself, to the Hawaiians, had connotations of
physical beauty, as in one's love interest, but also in
terms of a desirable bachelor. There was also apparently a
tradition that held that a fisherman could observe the behavior
of a pair of fish and it would serve as
a kind of portent as to what was going on
back home. So like, you know, certain things the parrotfish
(29:07):
was doing. It's like, okay, everything's cool back of the house.
Other things the parrotfish might be doing. It's like you
need to go back and check on your wife, that
sort of thing. Now, the parrotfish who also factors into
one of the stories of a legendary figure in Hawaiian mythology.
And I could not find a like a solid pronunciation
(29:27):
guide for this name, so I hope I'm saying it
somewhere close to correctly, and my apologies if I'm not
punia Kaya. This is in these stories. He's a dashing
young man who one day leaves his parents' house because
he feels this call of the ocean. He wants to
go fishing, and so he catches this young, supernatural fish
(29:48):
the first Ooh, and it makes it his pet, and
then he releases it where it becomes the parent of
all fish, and so afterwards he's able to go call
upon the fish to the or fellow fish to the fishermen. Yeah.
I was reading more about this in Native Use of
Fish in Hawaii by Margaret Titcomb, and the author makes
(30:09):
a connection to the manner in which parrotfish move along
in a school, often single file, seemingly led by a leader.
So that, yeah, this special trap was devised by the
early Hawaiians for use during a particular season. The trap
allowed them to allow the fish to file into the
trap led by the leader, but then they're unable to escape,
and they keep the trap in use during the May
(30:32):
June July season, collect enough fish for personal use, and
then release the rest, though another source I've looked at
seems to indicate that excess fish might have been harvested
to feed pigs and dogs, So I don't know. There
may be some variety in the practice, or there might
be a misconception on one side or the other, but
at any rate, this is how they caught them, and
(30:54):
I guess by virtue of that leader fish leads into
this idea that there's kind of like a fish that
is a friend of the people that will help you
catch more fish.
Speaker 3 (31:04):
Like it's the leader of the school is deliberately leading
them into the trap for you.
Speaker 1 (31:09):
Yeah, though not so much that it's like a trader fish,
but more than like it is this fish that a
like a legendary figure made a deal with that's sort
of thing. So yeah, this was a new one to
me as well. I don't think i'd heard this in
my previous trips to Hawaii. So and there may be
some more interesting partfish mythologies out there that I'll have
(31:30):
to turn up for the next episode.
Speaker 3 (31:33):
That's really interesting. I like it. As I promised earlier,
I wanted to come back and talk a bit more
about how parrotfish eat and a little bit about the
equipment they used to do it and what happens after
they do it after they eat. So one source I
was looking at here is a chapter in the Biology
(31:54):
of Parrotfishes by CRC Press twenty eighteen. And this chapter
was by Peter S. Wainwright and Samantha A. Price. It's
called Innovation and Diversity of the Feeding Mechanism in Parrotfishes.
And I'll probably come back to this in subsequent episodes
as well. But about the authors, Peter C. Wainwright is
a biologist at UC Davis and Samantha A. Price is
(32:15):
a biologist at Clemson, and so the authors here say
that how parrotfishes eat to the various species of parrotfish,
how they eat is quote one of the fundamental ecological
processes in coral reef ecosystems. So when you think about parrotfish,
you shouldn't just think of them as something you occasionally
(32:37):
see in a coral reef, but rather they are an
integral part of how coral reef ecosystems work, and kind
of the whole ecosystem doesn't really work without them. Now,
as we mentioned earlier, the feeding process of parrotfish involves
a lot of scraping and biting into hard stony materials.
(32:58):
Parrotfishes swim around coral reefs using their teeth to scrape
edible stuff off the outside of coral, and they break
off some coral and bring it along with them in
the process. Now, what is that edible stuff on the
outside of the coral. The authors say that it includes
primarily algae. Algae is a big part, but also detritis,
(33:20):
and in a marine context this usually means dead organic material,
so parts of dead organisms, fecal matter, all that yummy stuff.
Sometimes it will include bacteria, little colonies of bacteria, and
then they just say, quote a wide range of encrusting invertebrates,
so all kinds of little invertebrate animals that could be
(33:42):
found on a coral reef. This might include coral polyps themselves,
and it might also include things like sponges. Now, a
couple of sources I was looking at sort of classified
several different types of parrotfish feeding strategies, and the main
variation here seemed to be how how deep the parrotfish
would cut into the stony parts of the coral. So
(34:05):
you might have some that are referred to more as
browsers or grazers, that tend to typically just take the
soft parts off the surface of the coral. You've got
scrapers which scrape the coral a little harder and get
some of what's underneath. And then you've got what are
called excavators, which are really just taking chunks out of
the hard stuff. So the parrotfishes swim along on the reef,
(34:27):
scraping the stuff off with their outer teeth or excavating
bits of it and inevitably leaving scars on the rock
or the coral skeletons as they go. And then all
of this mixture of both hard and soft parts goes
into the mouth, where it is subjected to a second obstacle,
which is the trial of the inner jaws. Because parrotfishes
(34:50):
don't only have these fascinating outer teeth, they have a
second set of teeth at the back of their mouth,
known as the fyringeal jaw. Now you might have read
about pharyngeal jaws with respect to other animals that have them.
A number of fish and creatures that live in the
sea have them, and a well known example is the
(35:11):
more eel.
Speaker 1 (35:12):
That's right, Yeah, And of course, you know, those of
you who've watched any amount of science fiction, you might
also note that very angel jaws from in the world
of fictional monsters, we do have, of course, the alien xenomorph,
at least the main morph of the creature that we
see in those films, where we see this inner jaw
(35:33):
that functions as both a feeding mechanism and a puncturing weapon,
while elsewhere in the alien universe we see other morphs,
such as the deacon and the neo morph, that boast
extendable inner jaws rather than a secondary set of jaws.
But yeah, generally you often see some like comparative biology
write ups, and I think I've done right up to
(35:54):
this and this nature in the past, where when you're
comparing xenomorph physiology to the now world, the more a
eel is like a prime stopping point of comparison.
Speaker 3 (36:05):
Now, the exact design of the fyrngeal jaw in the
xenomorphos a little bit extra like. I'm not aware of
any examples in the in the natural world where like
the inner jaw comes out of the mouth and stabs
like a spear, like bites through the torso of a
prey animal. The inner jaws in the cases I'm aware of,
tend to stay mostly within the outer jaws, but they
(36:28):
do do something fascinating and perhaps to some horrifying. So
in the case of the more a eel, which is
a predator, the fyryngial jaw helps the eel capture and
swallow large live prey animals without allowing them to escape.
So the eel first bites the prey with its regular
outer jaws. These are the jaws you'd see, you know,
(36:49):
with the teeth. They have backward curving teeth, and those
the orientation of the teeth, the backward curving nature of
them helps them keep the keep the prey in place
without allowing it to back out and escape. And then
while the eel is holding the prey in place with
these outer jaws, the inner jaws reach up from out
(37:10):
of the eel's throat to bite the animal and pull
it further inside the mouth and down into the esophagus.
So it's a two step capture and conveyance mechanism. Now
just to stick with the more eel in a sidebar
for a second, I got interested in this. The evolutionary
reasoning for this is an interesting question. Apparently, most predatory
(37:33):
fish rely in large part on suction to capture and
swallow their prey. So these other fish use their muscles
to rapidly expand the mouth through the throat cavity, and
so when it expands like this, it creates a negative
pressure and it sucks in water from outside the mouth,
including the prey in that water. And this suction mechanism
(37:56):
can either be the action that pulls the prey into
the mouth in the first place, or it can also
be that after a predatory fish bites the prey with
its jaws, the suction mechanism then pulls the prey farther
into the mouth and down into the esophagus.
Speaker 1 (38:12):
Yeah, the scorpion fish is a great example of this,
and you can find some great video footage of this
where it's an ambush predator down there, hidden on the
floor of the sea, and then as its prey comes by,
it just kind of goes woomf and just rapidly sucks
it into its mouth and it's just gone like that.
And the scorpion fish is of course you'll note get
(38:32):
very robust looking, kind of frog ish looking, and that
is key here too, Right.
Speaker 3 (38:39):
So I was reading a two thousand and seven National
Science Foundation press release about research on moray eels published
in Nature that year, and the studies lead author, a
UC Davis scientist named Rita Meta, says that her study
found because of the way more eel bodies are shaped,
they're not able to generate much suction in the mouth cavity,
(39:02):
so instead they have this secondary set of jaws in
the throat. More eels are predators that often live in
coral reefs and they hide in little holes, gaps and
niches in the reef, and so a possible reason given
for this evolutionary difference why they have the feryngial jaws
instead of the suction mechanism is that by having pharyngeal jaws,
(39:25):
they can attack and swallow relatively large prey in tight,
confined little spaces where there would not be enough room
for them to expand the mouth or throat cavity to
create suction.
Speaker 1 (39:38):
Fascinating, it makes perfect sense.
Speaker 3 (39:41):
So that's an interesting idea, But I also think it's
an interesting parallel. You've got more eels and parrotfishes, which
are both coral reef dwellers and both have forryngial jaws,
but they use these inner jaws for totally different purposes. Again,
in the eel, it's to pull the prey down the
throat once it's in the mouth. Parrotfishes are again not
(40:02):
generally going to be chasing large live prey. They're mostly herbivores,
and they eat by scraping or gouging the coral and
getting stuff off the outside or in the layers underneath
the surface. This material that they scrape off of rocks
and coral, which mostly includes algae and other microbial organisms,
but also dead organic matter and coral skeleton bits, is
(40:25):
pulled down into the pharyngeal teeth where to quote Wainwright
and Price, it is quote mixed with mucus and ground
to a fine slurry before being passed to the intestines.
And Rob I was just looking up some photos of
parrotfish phyngeal teeth, and oh boy, what what are we
(40:45):
looking at here? These are some organs like they're clearly
specialized for grinding down this mixture of hard and soft
substances into a mucous, lubricated slurry. But some of these
pieces of parrotfish anatomy look like a car transmission gear
made out of bone. Others look like a bone pine cone.
(41:06):
It's it's interesting.
Speaker 1 (41:08):
Yeah, yeah, yeah, it does kind of look like interlocking
gear teeth.
Speaker 3 (41:13):
Yeah, it's crazy. So the digestive system extracts nutrients from
this slurry, and then the parrotfish excretes what is left over,
which is a big part of which is sand. Because
they're grinding down this coral. They bite off and scrape
off pieces of coral, grind up that coral with the
nightmare throat teeth, and then they poop sand. So I've
(41:37):
read it described that if you swim around with these buddies,
you will see them just like letting out kind of
poofs of sand or blasting clouds of sand into the
water column.
Speaker 1 (41:47):
Yeah. Absolutely, yeah, Like they're just they're kind of constantly
doing it. I mean, it makes sense. They're grazing and
they're kind of like goats, and they're kind of pooping
like goats, except it's coming out in this kind of
like puff of sand. And I know you included some
photos here where it's like more than a puff. It
looks like they're crop dusting. It's quite impressive.
Speaker 3 (42:08):
In fact, parrotfish poop so much sand. They are by
themselves a significant source of the bioroosion of coral and
a significant source of fine grained white sand in certain environments,
as in, when you are walking along a beautiful white
sand beach on some tropical island, there is a very
(42:31):
good chance a large proportion of the sand under your
feet is parrotfish poop.
Speaker 1 (42:37):
That's right. They are beach creation machines, and some of
the estimates for individual sand creation are quite stunning.
Speaker 3 (42:45):
Unbelievable to me. Actually, Like I had no idea about
this going in, So you might be thinking, yeah, how
much sand can these fish really poop? Again? It depends
where you are. There are obviously other sand creation mechanisms
in the sea, so this is not the only one.
But in some place parrotfish are responsible for a lot
of the sand that's there. One example I came across
(43:06):
is a paper in the journal Geology from twenty fifteen
by Perry at All called Linking reef Ecology to island building.
Parrotfish identified as major producers for island building sediment in
the Maldives and so again this is by Perry at All,
and so the Maldives Archipelago. This is an island chain
that contains approximately twelve hundred individual reef islands, which are
(43:30):
islands that are made entirely out of sediment that is
produced from underwater coral reefs. So the primary reason these
islands exist is that there are coral reef ecosystems on
an underwater platform. Of course, the reefs themselves are mostly
made up of the calcium carbonate skeletons of stony coral polyps,
(43:51):
and over time these coral reefs decompose into sediments like
sand and gravel. Parry at All right quote all coral
reef islands are inherently dependent on their surrounding reef habitats
not only because they provide the foundations for island development,
but also because they are the primary production sites for
the sediments necessary to sustain island building, growth and maintenance.
(44:15):
So without sediments from the coral reefs decomposing into sand
and gravel, you may not have an island here. But
the authors of this study say before their research, how
exactly that sediment is produced from the coral reef is
poorly quantified, so they investigated they're looking at where does
the sediment come from, and they used the example of Vakaru,
(44:39):
which is an interior reef island in the Maldives. They
found that the area around this island produces about six
hundred and eighty five thousand kilograms of sediment per year,
about seventy five percent of which comes from a place
they call the outer reef flat. So if you look
at the island from above, you'll see the part that
rises above water and is forested and has plants and
(45:01):
all that, the beach surrounding it, and then there's sort
of an inner lagoon and then an inner reef ring
and an outer reef ring. So most of the sediment
is coming from that outer ring of coral reef environments
in the water, about seventy five percent of the sediment
comes from the outer reef flat. Now within that outer reef,
(45:22):
which creates about seventy five percent of the island's yearly
supply of new sand, the author's discovered that more than
eighty five percent of the sand is produced by parrotfish.
And if you're curious what the second place was. The
runner up producer of reef sand in a distant second
place at about eight point eight percent in the outer
reef is a type of macroalgy called halimata, which makes
(45:47):
like calcified body parts and then those get shed and
eventually decompose a breakdown into sand. But almost all of
it is coming from what the parrotfish excrete. So parrotfish
are continually defecating this island into existence, and they remain
critical for maintaining its existence the author's right quote. The
(46:08):
generation of sediments suitable for maintaining this reef island is
thus critically dependent on a narrow zone of high productivity reef,
but most especially on the maintenance of healthy parrotfish populations
that can convert reef framework to sand grade sediment, and
so the parrotfish are crucial for the health of island
(46:29):
environments like this. But this is not just true of
these tiny coral reef islands that are generated from coral
reef sediments, even on many other coasts and larger islands,
where the island itself might be, you know, have other
geological explanations, like it's not just sand rising out of
the water. It might be a volcanic island or the
coast of a continent or something. In places where there
are coral reefs, beaches in many cases are still largely
(46:55):
parrotfish lavatory constructions. A figure sighted in several reputable looking sources,
though I couldn't find the exact origin of it, is
that around seventy percent of the sand on the White
Sandy Beaches of Hawaii is parrotfish excretion. It's hard to imagine,
like you're walking on a beach or even on a
(47:15):
whole island, and to imagine it having a biological fish
digestive system origin of this kind.
Speaker 1 (47:24):
I know, it's just it's crazy. It's one of those
mind blowing facts though that again, it gets pointed out
a lot when you are going to these places and snorkeling,
it becomes easy to sort of take for granted and
you have to sort of remind yourself. Then when you're
walking on the beach, it's like, no, for real, all
this sand and it's still kind of you know, beggars
(47:44):
the imagination.
Speaker 3 (47:46):
Yeah. Now, another thing that's interesting is that, of course
we know now that parrotfishes are very important for the
for creating the sand that in some cases makes it
possible to have an island and like these reef island
(48:06):
environments or helps replenish the beaches. But you might think,
on the other hand, well, the parrotfishes are the enemy
of the coral reefs though, because they're preying on, you know,
the coral. They're like scrape in the coral. In fact,
it is thought that parrotfishes help protect coral reefs because
as they're going along taking bites out of the barrel
(48:29):
coral reefs, they might be leaving scars in them, biting
pieces off, taking chunks out, But by grazing in this way,
they prevent the reefs from becoming overgrown by things like
algae and other encrusting invertebrates like sponges and stuff. So
they may eat some coral as they munch along, but
overall they keep the coral reefs healthy.
Speaker 1 (48:52):
That's right. This is a very important fact concerning like
necessary conservation for parrotfish because and it goes beyond that too,
Like I was reading that by constantly eating algae off
the coral. Again, they're constantly in doing this cleaning the coral,
creating new surfaces on the coral. And this is where
(49:13):
baby corals can attach and grow, so that's in play.
And on top of this, yeah, they're keeping like seaweed,
which remember is a microalgae. They're keeping seaweed growth in check.
And this is apparently one of the prime results of
parrotfish overfishing in parts of the Caribbean and the Pacific
seaweed overgrowth. And I was even reading this is from
(49:36):
Kramer at all. In twenty seventeen's prehistorical and historical declines
in Caribbean coral reef accretion rates driven by loss of parrotfish.
The authors here say that we see this connection proven
out in sediment fossils. There's a strong observable connection between
declines and coral accretion rates and parrotfish abundance. So and
(49:57):
it's more evidence that we need to conserve parrotfish in
order to help prevent coral reef environments from becoming quote,
algael dominated habitats. And yeah, so this is worth keeping
in mind. If you're traveling somewhere and parrotfish is on
the menu, it's advisable to eat something else. And indeed,
there are a number of efforts and protections in places
(50:19):
around the world to help protect these populations like the
parrotfish are a vital part of those coral environments which
are already threatened in a number of ways. This is
one that we can we can we can do a
lot to help coral reefs, but not eating parrotfish is
perhaps even more accessible than some of the things we
(50:40):
need to do to protect them.
Speaker 3 (50:42):
Now, there's one more brief thing I wanted to get
into before we wrap up part one here, and that
is about the material makeup of parrotfish teeth. I was
reading about this in a press release for the Lawrence
Berkeley National Laboratory. This was published in twenty seventeen. It's
called X raysor Reveal the Biting Truth about Parrotfish Teeth
(51:02):
by Glenn Roberts, Junior. And so this is talking about
research conducted at the Berkeley Lab, which used X rays
to examine parrotfish teeth and better understand what makes them
so resilient in the face of essentially scraping, biting, and
chewing on rocks all day. You know, on these these
coral skeletons are are not soft, you know, they're hard
(51:24):
calcium carbonate, and they're just these teeth are relentlessly munching.
So the particular parrotfish species in question was the steep
head parrotfish also known as the blunt head parrotfish scientific
name Chlorurus micro rhinos. And in this analysis, the researchers
found that the resilience of prot parrotfish teeth was due
(51:46):
to this woven microstructure of minerals in the enameloid of
the teeth, and the article compares it in fact in
structure to chain mail, which I thought was interesting. So this,
this microstructure creates a tooth the material that is incredibly
hard at the biting surface. The article points out that
(52:07):
the hardness of the biting surface is about five hundred
and thirty tons of pressure per square inch and they
compare this to the weight of eighty eight African elephants
on a single square inch of space. Now that microstructure
of the teeth fits into a larger structure, the sort
of morphology of the jaw, which is that these parrotfish
(52:30):
have like fifteen rows of teeth totaling about one thousand teeth,
all fused together, biologically glued or cemented together into this
single beak like structure, and the stiffness of the underlying
mineral crystals increases as it goes toward the tip the
biting surface. And the article quotes one of the researchers
(52:51):
involved named PUPA. Gilbert, who is a professor in the
physics department at the University of Wisconsin Madison, who says, quote,
fish teeth are the coolest biominerals of all. They are
the stiffest, among the hardest, and the most resistant to
fracture and to abrasion ever measured. And so given the
incredible material qualities of these parrotfish teeth and beaks, researchers
(53:15):
are looking into ways that the woven crystals of parrotfish
teeth might be used as an inspiration for human engineering,
a design pattern that could be reproduced in synthetic materials
to create a tougher, more resilient product.
Speaker 1 (53:29):
Now, just a couple of notes about these teeth for one.
On one hand, to come back to the alien xenomorph.
You know, it is interesting that they're sometimes described, at
least for some of the morphs, as possessing metal teeth,
and here we have the parrotfish, whose teeth are sometimes
described as being stronger than many metals metals, so it's
kind of interesting comparison there. Also, you know, inevitably there
(53:52):
is the question in the same way that we can't
look at a creature that is biting coral and you know,
think about our own teeth biting coral, we also can't
help but look at a creature with interesting teeth and
wonder what happens if I get bitten by one of these?
So I mean to be clear, you know, humans are
not on the menu for the parrotfish. There are accounts
(54:15):
of parrotfish rarely biting humans, though it does seem very rare,
and the incidents I was looking at, most of them
seem to be related to incidents with fishermen who were
actively harvesting them or you know, engaging with a trap
or something. But they have bitten humans before, so it
(54:35):
can happen. But I mean that can be said of
a lot of creatures, like you know, a horse can
bite you.
Speaker 3 (54:40):
Oh lord, why did I google this? But I did?
Speaker 1 (54:43):
Oh did you just google? You may have googled one
that comes up a lot.
Speaker 3 (54:47):
Came across a news article that claims to be a
photo of a wound from somebody who was bitten by
a parrotfish, and it looks it's grotesque. Listeners be warned.
Speaker 1 (55:00):
Yeah, there's a particular story that comes up in search
involving a fisherman, that is that was bitten in a
delicate area by one of these these parrotfish. So uh yeah,
I you know, weighed carefully if you decide to pursue these,
uh these stories for yourself. But yeah, it can happen,
it has happened, but uh, these are generally not considered
(55:21):
you know, risky fish, and people snorkel around them almost
constantly without issue.
Speaker 3 (55:27):
They're not looking to bite you. They're they're just trying
to go about their business. They're scraping.
Speaker 1 (55:32):
They're buzz't like bees, they have so much coral to scrape,
Like biting you takes time away from vital coral scraping time,
all right, well, we're gonna go and close up this
episode now, but we actually have even more exciting content
to cover about the parrotfish we didn't. We briefly mentioned their, their, their,
(55:53):
their sex changing ability, so we're going to get into
that for sure. Uh. There's also some other stuff that
will and I think in ways get us even closer
to that xenomorpha area again.
Speaker 3 (56:03):
So yeah, we're gonna have some cocoonings, some all kinds
of good stuff to get into next time.
Speaker 1 (56:08):
Yeah, yeah, so tune in for that. In the meantime,
I love to hear from anyone else out there who
has personal experience being around parrotfish. You know, we're not
encouraging anyone to actively seek out and eat parrotfish, but
you know, it has been a tradition of cuisines. So
if you would like to ride in and share your
culinary experience with parrotfish, If you have tasted a parrotfish liver, yes,
(56:32):
we would like to know what that is like that
We just would like to know. We'd like to know
what the Romans were into when they were consuming their
parrot fish meals. So write in. It's all fair game
as always, you know, if you have. When you do
write into us, you can always flag something is and
say hey, don't use my name on this, I want
it to be anonymous. Or you can say hey, this
(56:53):
is information for you, but don't actually read this. That's
fair as well. Just write in. We would love to
hear from you. Just a reminder that Stuff to Blow
Your Mind is primarily a science and culture podcast, with
core episodes on Tuesdays and Thursdays, listener mail on Mondays,
short form episode on Wednesdays, and on Fridays. We set
aside most serious concerns to just talk about a weird
film on Weird House Cinema.
Speaker 3 (57:13):
Huge thanks as always to our excellent audio producer JJ Posway.
If you would like to get in touch with us
with feedback on this episode or any other, to suggest
a topic for the future, or just to say hello,
you can email us at contact at stuff to Blow
your Mind dot com.
Speaker 2 (57:35):
Stuff to Blow Your Mind is production of iHeartRadio. For
more podcasts from My Heart Radio, visit the iHeartRadio app,
Apple Podcasts, or wherever you listen to your favorite shows. A. B.
Hey, you welcome to Stuff to Blow your Mind. This
is Robert Lamb. Today's Saturday, so of course we have
a vault episode for you. This is going to be
the Parrotfish Part one. It originally published five twenty one,
twenty twenty four. I hope you enjoy.
Speaker 2 (00:21):
Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Speaker 1 (00:31):
Hey you welcome to Stuff to Blow your Mind.
Speaker 3 (00:33):
My name is Robert Lamb and I am Joe McCormick.
And today on the podcast we're going to be beginning
a look at parrotfish or parrotfishes. This is one of
those topics that literally just started with me looking at
a picture. I was staring at a picture of a
bizarre goofy, goofy appearing animal and thinking I want to
(00:56):
know more about this critter, and then discovering that indeed,
this organ is a is a peculiar and fascinating story,
and there is so much more to it than you
might guess just by looking at it at its strange
beak or toothy mouth.
Speaker 1 (01:10):
Yeah, parrotfish are pretty fascinating. I've snorkeled among the parrotfish
many times and can attest that they're curious looking fish.
They're pleasure to watch. They're often very colorful. So I'm
going to throw in more of my observations as we proceed.
But I think, on the other hand, in coral reef environments,
(01:31):
where I've done most of my snorkeling, and where a
lot of snorkeling takes place, they can actually be easy
to take for granted because they're generally around and you
know significant numbers that these environments. Often these are protected
reefs that I've been to, they're not particularly shy, they're
easily found in shallow water, so you know, oftentimes you're
(01:52):
dealing with like reef environments that are either very accessible
just from the shore or just a very short boat
ride sort of a situation. So in a way, it's
easy to take them for granted because they're there, you
see them, and then you end up focusing a lot
more of your attention looking for some of the harder
to find organisms that are going to live in these
(02:12):
reef environments. So it's actually a great opportunity to stop
and focus on this remarkable fish that I honestly had
never really thought about devoting a whole episode or series
of episodes too. But there's more than enough to talk about.
Speaker 3 (02:25):
I've never snorkeled and seen them in person, so I'm
envious of this experience and maybe I will someday. I
look forward to that. But I've seen video and in
some cases that there's almost a feeling of like bees
buzzing around a shrub that's covered in flowers. You know,
it's just kind of the general gentle grazing activity of
(02:45):
some animals surrounding a plant like structure, but in this
case it's of the big skeleton of stony corals.
Speaker 1 (02:53):
Yeah, the grazing observation is key, and it's something that
has long been observed for these creatures, as we'll discuss
going back into ancient times, even when we didn't have
snorkelers as we think of them today, you still had
individuals fishing in shallow environments, sometimes fishing for the parrotfish
in question, and observing that, Hey, these creatures appear to
(03:15):
be grazing, unlike most of the fish that we are observing.
Speaker 3 (03:20):
So parrotfish are not one species, but a larger group
of fish containing about ninety something individual species. I've seen
different estimates on the numbers. I think it's older ones
that say, maybe like eighty species. Others say closer to
one hundred, but I think ninety something is about right.
They range broadly in terms of size and appearance. In fact,
(03:42):
they range broadly in terms of appearance even within a species,
as we'll get to maybe in this part or maybe later,
but some adult parrotfish are less than a foot in length,
and some of the largest are almost four feet or
about one point two meters in length, so they can
range from medium small to quite large. These fish are
sometimes taxonomized as a family called scarid and in other
(04:06):
cases regarded as a subfamily of Labridy, which are commonly
known as the rasses. I think you can see some
morphological similarities with the fish called rasses, kind of the
way they swim, the way they use their pectoral fins,
and stuff like that. But a characteristic come into many
parrotfishes is that they tend to live around coral reefs,
(04:27):
especially in the tropics.
Speaker 1 (04:29):
I also want to throw in there that there are
occasionally fish that are just sort of commonly called a
parrotfish or informally called a parrotfish, that are not parrotfish,
mainly the blood red parrot chick lid, which apparently is
a popular aquarium species.
Speaker 3 (04:45):
This is not.
Speaker 1 (04:45):
Actually related to proper parrotfish that we're going to be
talking about here today. And I've also seen some some
fossil evidence that is sometimes categorized as a parrotfish in
a way that I'm not sure actually lines up with
what we're talking about here. But if you've seen a
picture of a parrotfish proper parrotfish, indeed, go ahead and
(05:06):
look one up if you're in a position to do so.
I think it's hard to miss what we're talking about.
These are very recognizable fish, though again they do very
greatly in coloration.
Speaker 3 (05:17):
Size, that's right. Yeah, So if you look up pictures
of them, you'll see that they're often kind of elongated
in body. They have different shapes. Some are more kind
of that elongated oval shape and others are blunter in
the front with like blunt heads. They're in fact, our
parrotfish called like the blunt head pair of parrotfish or
the steep head parrotfish. The coloration you'll see on them
(05:40):
depends on some facts about them and not just their species,
but sometimes they have quite bright patterns of almost neon color,
surprising colors to see in nature. Very you know, tropical
kind of color signals. There's one picture I kept seeing
where the fish had a color pattern that reminded me
of the as design from paper cups in the nineties.
(06:02):
But if you also threw some hot pink in there.
So there's a lot to take in when you look
at look at a parrot fish. But before you notice
any of that, but you know, the head shape, the
body shape, the coloration patterns, what you will probably notice
first about any given parrotfish is the mouth. I mean,
look at these chompers. Rob I've included just several pictures.
(06:24):
I know you've seen them in person, so your experience
of the teeth the beak is probably more direct and
visceral and profound even than mine. But I was just
looking at these pictures for quite a while the other day,
and my God, that these beaks, these mouths, it's it's incredible.
Speaker 1 (06:41):
Yeah, Yeah, their mouths are quite fascinating in some of
the photos. Yeah, they can actually look a little intimidating, though,
I would say based on the species that I've primarily
been exposed to in Hawaii and the Caribbean, they tend
to look more silly then than threatening. But they're definitely
(07:02):
very cool looking, not taking anything away from that.
Speaker 3 (07:05):
Yeah, So I guess it varies from species to species.
So parrotfish have these rows of fused teeth on the
outside of their jaws, which, in some cases, as the
name implies, look very similar to the beak of a parrot.
It can look like a bird's beak, But in other cases,
these fused rows of teeth look like jagged monster jaws,
(07:27):
sort of like a horseshoe shaped ceramic saw blade. But
in other cases still they are like a big goofy
cartoon overbite, like Alfred Y Newman's mouth got hit with
the radiation from the amazing Colossal Man.
Speaker 1 (07:43):
Now I want to throw in one more note here
about species classifications coloration. It is worth noting that with
parrotfish that classifications in naming have long proof challenging because
they tend to show different colorizations depending on an individual's
age and sex. So, for example, was pointed out by
the Waikiki Aquarium, the spectacled parrotfish is reddish brown when
(08:08):
it's a juvenile, then it develops a pale tail spot
when it becomes a reproductive female, and then develops bright
blue green coloration. With pink markings when it becomes male.
So you can imagine a lot of the early confusion
at figuring out, well, what is a different species of parrotfish,
and you will have multiple species of parrotfish in a
given region, and then what is just parrotfish are the
(08:31):
same species that's just in a different phase of its
life cycle.
Speaker 3 (08:34):
That's right. In fact, I was even reading like some
blog posts by marine biologists who had worked with these
animals firsthand, talking about just how difficult it was sometimes
to identify these fish because of all the variation even
within species. But to come back to the main attraction,
the teeth, the beaks. The crazy thing is, as much
(08:56):
as these look like biting teeth in some cases, in
reality they are scraping teeth. Because parrotfish are primarily herbivores
for the most part, they do not eat by swimming
around biting semi circular chunks out of other fish, as
you might imagine just looking at their mouths. They mostly
(09:16):
eat by grazing along the hard surfaces of coral reefs,
scraping away algae and soft bits of coral and other
bits of organic matter, along with some hard bits of
the coral skeletons with their teeth, So that's what the
teeth are for. These are for grazing. These are the
(09:37):
life of a herbivore, not the life of a predator.
Speaker 1 (09:40):
Now, of course, as this we'll be discussing here. Coral,
of course is hard matter. And one of the crazy
things about snorkeling with parrotfish is that you don't just
get to watch them, you get to listen to them.
So as they feast on the algae that's growing on
the coral, they're scraping the coral, and it's producing a
sound in the snorkeler's ear that I would compare to
(10:02):
kind of a static paper crunching or even the snap
crackle crunch of rice crispies and milk. It's one of
those things when when you first explore. When I first
experienced it, I wasn't exactly sure what I was listening to,
because it's kind of like, oh, is there something in
my ears and it's just just the sound of the
ocean and so forth. But no, it it becomes clear,
(10:23):
and it's often pointed out to one that yeah, this
is the sound of these the parrotfish feeding, and yeah,
it's pretty remarkable. So you listen to them, you watch them,
and they just become part of the background sound escape
to your snortling.
Speaker 3 (10:38):
It's a funny other comparison to bees, almost, you know,
the way the buzzing of a bee just kind of
like blends in becomes the ambient sound of a landscape.
The tooth and beak scraping on coral sound produced by
these animals is maybe comparable to the buzzing of bees.
Speaker 1 (10:54):
Yeah, and it's also consistent, like that's the other thing.
They're constantly grazing, and therefore it is a constant soundtrack.
It's not like say, the occasional sound of a woodpecker
in a forest, Like it's just NonStop. So it's just
in the background, and you could easily if you didn't
know what you were listening to, you might not realize
that this is the sound of organisms feeding.
Speaker 3 (11:14):
Now, I think there are probably other people out there
like me, Rob, I don't know if you fall into
this category of people whose minds are easily captured and
revolted by just imagining kind of tooth trauma. Like I
very easily can like get a shiver across my whole
body when I imagine, say, trying to bite down on
a rock, And that is what you have to constantly
(11:37):
imagine when you're thinking about these animals. It's not technically
a rock, though I guess in some cases they do
scrape rocks as well, but most often it's going to
be like a rock. It will be the skeletons of
stony corals. But can you just imagine that, as painful
as it might be, imagine having to live by like seeing,
you know, a moss covered rock and thinking I'm going
(11:58):
to use my front teeth to scrape that bad boy clean,
and I'm going to bite off some chunks of the
rock as I'm getting the moss off of it. Delicious.
Speaker 1 (12:07):
Yeah, yeah, it can be a bit squeamish. It can
make one a bit squamish sometimes imagining these other dental
scenarios in the natural world.
Speaker 3 (12:16):
So I want to talk a bit more later about
how parrotfish eat and get their nutrition, and a bit
more about their teeth. But before we do that, Rob,
I think you've found some interesting stuff about writings on
parrotfish from the ancient world. Yeah.
Speaker 1 (12:29):
I did, And this was a whole avenue that I
had not been down. I had no idea this was
a thing. So again, given that species of parrotfish are
found around the world, and that they can frequently be
found in shallow water, and that they have traditionally been
caught for culinary purposes for food, it should come as
(12:52):
no surprise that these fish were known to people so
the ancient world, you know, even in times when folks
didn't have axe to the underwater world in any way
comparable to what we have today, they still knew what
these fish were, and in some cases they had some
rather insightful ideas about what they were doing. In other cases,
(13:13):
there are some very long standing misconceptions about what parrotfish do.
So in this we're going to actually bring up the
work of our dear old friend Roman historian Plenty of
the Elder, who is one of several sources of antiquity
that discusses the parrotfish, you know, and of course there's
a lot of shared content and so forth going on.
(13:35):
The fish would have been known as the scars. This
is of course, now where we get the name of
the genus for parrotfish, and we might assume that in
particular we're dealing with discussions of the Mediterranean parrotfish, though
based on what I was reading. Also, you had like
the red sea parrotfish that was also known to various
cultures of antiquity. So Plenty of the Elder in the
(13:58):
Natural History seventy nine CE rites at the present day
the first place, and this is he's speaking from a
culinary perspective here. First place at the Roman table is
given to the scars, the only fish that is said
to ruminate and to feed on grass and not on
other fish. It is most commonly found in the Carpathian Sea,
(14:21):
and never of its own accord passes lectum a promontory
of trois now. Nineteenth century naturalist George Cuvier and his
annotations to Plenty points out again that the first place
here is in reference to the Roman dinner table, where
this fish was celebrated for several attributed characteristics that I'll
(14:43):
get to in a minute, and was also typically quote
salted with the intestines in it. M okay, and some
Roman authors actually absolutely insisted that you do not eat
this fish without the intestines included. It's just too delicious
this way.
Speaker 3 (14:59):
Oh boy, So like, are you saying they would eat
the intestines directly or it's like you got to leave
the intestines in there to give them meat some flavor.
Speaker 1 (15:08):
You've got to leave them in. Yeah, okay, And I
know they were often in many cultures salted and then traded,
So I'm offhand, I'm not entirely sure if this is
a definite case of we're talking about salted parrotfish with
the intestines still in, or some other form of preparing them.
But at any right, they really liked it. There are
(15:28):
also Roman references to eating parrotfish livers as a delicacy.
Speaker 3 (15:33):
Mm so all the value here is just for their
flesh as food. This is a first place distinction that
would probably not be so flattering to the fish itself, right.
Speaker 1 (15:43):
Right, And the Romans weren't alone in appreciating eating parrotfishes.
We'll get to some other far flowing examples. Plenty of
humans have eaten parrotfish and still eat parrotfish. The Greeks
love them. There's some I think twenty species of Mediterranean parrotfish. Again,
there's the red sea parrotfish, considered a delicacy in antiquity,
(16:05):
And in both of these cases, I believe they were
often dried and then widely traded. I've read that in fact,
they were easily dried. I'm not sure about the particulars
of that, but I'll take their word on it that, Okay,
this is a fish that is easier to dry and
prepare and then trade across distances. You don't have to
eat it fresh by the seaside. Anyway, it was celebrated
(16:30):
at the Roman table, not just because you ate it
salted and with the guts in it, but also for
several reasons, according to Cuvier, and I think a lot
of these seem to get down to the fact that
I'm assuming the Romans liked a great story at the table.
You know, it's not just about what the fish smells like,
taste like, looks like on the plate, but also what
(16:51):
is the story of it, what ideas are wrapped up
in this particular organism. So here that first of all,
it was thought to be the only ruminating fish.
Speaker 3 (17:00):
So so wait, does that mean ruminating as in like
a like chewing the cud like a cow or a sheep.
Speaker 1 (17:07):
Yes, though basically I think what this comes down. First
of all, they're not truly chewing the cut. They're not
truly ruminating, you know, they're not chewing something that has
previously been chewed and swallowed. They are grazing like a cow.
And I think it has to do with observations of
these animals grazing, and it's like, oh, look they're they're
(17:29):
like a cow. They're ruminating. But still the idea that
they're ruminating, the idea that they're chewing their cut continues
to be mentioned all through antiquity on all the way
up through like medieval besty areas those some voices such
as Saint Ambrose in the fourth century said that did
point out the chud the cud chewing thing is not accurate,
(17:50):
that's not what they're doing. So but but still a
lot of misinformation about these fish persisted for a very
long time now. As Aristotle also observed in History of Animals,
the parrett fish were thought to be vegetarians, and indeed,
I guess you could say they're essentially herbivores. Many sources
(18:11):
will classify them as such, but also note that they're
maybe more more correct to say that they're algavores. But
still ancient people observe that these fish are not eating
in the same way that other fish are.
Speaker 3 (18:23):
Wow, this is something I feel like I should know.
The answer to, but I actually don't what is it called.
If you mostly eat you know, algae or plant things
that are like plants, plants, or types of bacteria microorganisms,
but sometimes you eat animals. But the animals are not
like you know, large moving animals, they're you know, basically
(18:45):
small invertebrate animals like corals.
Speaker 1 (18:48):
Yeah, I guess you would be some sort of a
coral war or something to that effect, right, But on
a number of the different fish databases that I was
looking at, yeah, sometimes they'll say herbivore, sometimes they'll say herbivore, algivore,
and then sometimes there's kind of an omnivore note as well.
I guess there's always a margin of error, as we've
discussed here, like even things like a cow, which we
(19:09):
think of is kind of a pure herbivore. There are examples,
as we've discussed on the show in the past, where
they have been observed to if meat is available, they
might eat set meat.
Speaker 3 (19:18):
But it is true that in the cases where parrotfish
are eating animals, they're not generally like chasing after other
fish and eating them or something. I don't know if
that might happen in some particular case but that's not
generally what parrotfish do. They're mostly going to be eating algae,
and then if they're eating animals, they're like marine invertebrate animals.
Speaker 1 (19:39):
Yeah, so I mean we can, I think basically say
that ancient people were correct in this judgment. Now, and
I guess maybe it made the story at the dinner
table a little more interesting. They're like, this is the
cow of the sea, that sort of thing. Now, the
third attribute that Kuvia mentions is quote because it had
the faculty of producing a sound. Now, perhaps I'm not
(20:03):
completely understanding Cuvier's point here, but I guess this is
referring to that constant chewing sound, that constant grazing sound
that one hears if your head is below water with
the fish. And again, this is not something that I
would think actually impacts one's enjoyment of dinner. But again,
I guess they liked a good story.
Speaker 3 (20:23):
You know, sometimes people they say they want their steak
rare by saying I want it still mooing. It's kind
a kind of a gruesome way to ask for it.
But people do say that. Can you say that, like,
I want my parrot fish steak rare? I want it
still scraping, I guess.
Speaker 1 (20:37):
So the fourth attribute that he mentions is quote for
its salacious propensities numbers being taken by means of a
female attached to a string. This, I guess alluding to
a supposed method of catching them. And I suppose the
Romans just like Randy food, though I'm not sure it
was actually considered an afrodisiac because I didn't see it
(20:57):
listed in another source I was looking at that had
to do with various foods of the Romans did believe
were aphrodisiacs.
Speaker 3 (21:03):
Uh huh okay.
Speaker 1 (21:05):
And then fifthly for its quote remarkable sagacity and affording
assistance to another when taken in the net.
Speaker 3 (21:13):
Huh, Now what would that mean?
Speaker 1 (21:15):
So this is referring to something that is that that
pops up in various old sources as well, and again
continues to persist for centuries. May be particularly referring to
a passage in Ovid. Ovid has the following passage quote,
(21:36):
the scas is caught by a stratagem beneath the waves,
and it length dreads the bait. Fraught with treachery, it
dares not strike the osers. This refers to a reed
basket with an effort of its head, but turning away
as it loosens the twigs with frequent blows of its tail,
it makes its passage and escapes safely into the deep. Moreover,
(21:58):
if perchance any kind scarus swimming behind sees it struggling
with the osures, he takes hold of its tail in
his mouth and it is thus turned away, and so
it makes its escape. So, okay, they have this idea
that these fish, these parrotfish, are essentially I don't think
(22:22):
you social would be the term, but they are. They
help each other out. They're capable of some form of
altruism where if they see another one of their kinds
stuck in one of these wicker basket traps, they will
try and help them out.
Speaker 3 (22:36):
Huh.
Speaker 1 (22:37):
And so this idea ends up sticking around for against
centuries and centuries. The idea that the scais or parrotfish
is not only a cud chewing herbivore of the sea,
but also a friendly fish that looks out for it's fellows.
Speaker 3 (22:50):
Well, that's fascinating, But I wonder what would this belief
about their like friendly behavior be based on. So the
idea is they help each other avoid traps, or say
each other from traps. Is there any modern research on this?
Speaker 1 (23:03):
So the main source I found on this, and this
is where I got turned onto the idea, it was
the blog of Fishtories. It's like histories and fish combined.
That's f I S H T O r I E
S dot net. It is a blog maintained by Sophia Hendricks,
an information scientist and historian of science. She discusses this
(23:24):
whole weird scenario with imagery of the parrotfish, because indeed
there's there's there's imagery associated. I included this illustration here
for you here Joe from a munch latter later source.
But but she does point out that based on what
we can tell, the fish are actually anything but friendly
to each other in these scenarios. Wicker baskets like this
(23:48):
are still used in some places to catch fish, she
points out. But she writes that the parrotfish have actually
been observed too violently attacked their fellow parrotfish that become
caught in the reeds of the fishing basket. So I
don't know that there's really much evidence to back this up.
(24:08):
I also get to an example here in a bit
involving traditional Hawaiian techniques for catching parrotfish that also uses
the basket, like the idea of being essentially that the
parrotfish are roaming around the corals feeding and they kind
of have these paths that they follow. They also tend
(24:28):
to sort of group together, and you may have what
seems to be a leader of the pack. And if
you set up these baskets at the right time, you
can catch them, and you can end up catching a
bunch of them even and you can then release the
ones you don't want, make use of the ones you
want to harvest. So I don't know. On one level,
it seems like, OK, you're ending up with an artificial
(24:50):
environment scenario here, where you're dealing essentially with captive fish
doing things in a captive environment and a high stakes
environment for them that they might not do otherwise, and
that may mean attacking each other that I guess could
also mean some sort of observational behavior, especially without the
aid of any kind of like snorkeling mask and so forth,
(25:12):
it might look like one's helping the others out. I'm
not sure, but still the idea becomes entrenched and the
image of the parrotfish helping each other escape from fishing
baskets ends up becoming a symbol of friendship. Oh yeah,
so this is something that she discusses at length in
another paper. This is something that published in Emblems of
(25:35):
the Natural World from twenty fifteen Ichthyology and Emblematics in
Conrad Gesner's Historia Piscium and Joham Kamarius's Kamarus the Youngers
Simbola at Emblemata. She points out that Plenty was one
of the key sources for this misconception, but plenty of
(25:56):
others sources in the ancient world echoed at Plutarch chimes
in on it, and so some sources identified this as
a sign of intelligence in the parrotfish, while other fishes
were often held up as examples of a lack of intelligence,
and fish, such as then Conrad Gessner's sixteenth century work
Historian Animalium, the mackerel was held up as a stupid fish.
Speaker 3 (26:18):
For example, how do you get that distinction as a fish?
Speaker 1 (26:22):
I don't know, I mean, maybe they just it's probably
a little bit unfair, right in some cases the macvil
looks to and you're basing everything on the human perspective
and human expectations of what an animal's intelligence is, you know,
whereas ultimately you can I think you can approach these
scenarios by saying, well, yeah, the parrotfish is in a
way a genius. It's as smart as it needs to
be to do the things that it does.
Speaker 3 (26:43):
Well. Actually, you know what, I wonder if some of
this I have no idea if it applies in this case,
but I wonder if some general ideas about smartfish versus
dumbfish come just from the experience of fishing for different
types of fish, because I know, you know, and people
who are into fishing right in and let us know
(27:04):
if this matches your experience. In my experience, people who
like to fish will like say that a fish that
is harder to catch is a smart fish, and one
that's easier to catches like a dumb fish. And I
don't know if intelligence actually has anything to do with
how easy they are to catch or not. You know,
might just have to do with like ingrained behavioral patterns,
(27:26):
someone responding distress or something.
Speaker 1 (27:29):
Yeah. Yeah, And it's kind of curious because it sounds
like if you have the right traps for it, catching
parrotfish is generally not considered super challenging. So but you know,
we have this other narrative that emerges again that they're
helping each other and that they can sort of help
each other escape from these traps and so forth. Now
(28:00):
I mentioned Hawaiian traditions because again, you know, you have
parrotfish all over and you do have them in the
Hawaiian Islands and in Hawaii. The parrotfish was historically known
in the Hawaiian language as uhu. The fish are prominent
there and they were eaten by Hawaiians. Traditionally. There's a
saying in Hawaiian, according to the online Hawaiian dictionary Ulucal,
(28:25):
that translates to my craving makes my mouth water for
the parrotfish passing before my eyes. The Hawaii Coral Reef
Network points out that not only were they a delicacy,
but their liver was especially favored. So again, you know,
you know, other side of the world, you still have
people eating parrotfish and also realizing that the liver is
apparently really good.
Speaker 3 (28:45):
Interesting.
Speaker 1 (28:46):
Now, the fish itself, to the Hawaiians, had connotations of
physical beauty, as in one's love interest, but also in
terms of a desirable bachelor. There was also apparently a
tradition that held that a fisherman could observe the behavior
of a pair of fish and it would serve as
a kind of portent as to what was going on
back home. So like, you know, certain things the parrotfish
(29:07):
was doing. It's like, okay, everything's cool back of the house.
Other things the parrotfish might be doing. It's like you
need to go back and check on your wife, that
sort of thing. Now, the parrotfish who also factors into
one of the stories of a legendary figure in Hawaiian mythology.
And I could not find a like a solid pronunciation
(29:27):
guide for this name, so I hope I'm saying it
somewhere close to correctly, and my apologies if I'm not
punia Kaya. This is in these stories. He's a dashing
young man who one day leaves his parents' house because
he feels this call of the ocean. He wants to
go fishing, and so he catches this young, supernatural fish
(29:48):
the first Ooh, and it makes it his pet, and
then he releases it where it becomes the parent of
all fish, and so afterwards he's able to go call
upon the fish to the or fellow fish to the fishermen. Yeah.
I was reading more about this in Native Use of
Fish in Hawaii by Margaret Titcomb, and the author makes
(30:09):
a connection to the manner in which parrotfish move along
in a school, often single file, seemingly led by a leader.
So that, yeah, this special trap was devised by the
early Hawaiians for use during a particular season. The trap
allowed them to allow the fish to file into the
trap led by the leader, but then they're unable to escape,
and they keep the trap in use during the May
(30:32):
June July season, collect enough fish for personal use, and
then release the rest, though another source I've looked at
seems to indicate that excess fish might have been harvested
to feed pigs and dogs, So I don't know. There
may be some variety in the practice, or there might
be a misconception on one side or the other, but
at any rate, this is how they caught them, and
(30:54):
I guess by virtue of that leader fish leads into
this idea that there's kind of like a fish that
is a friend of the people that will help you
catch more fish.
Speaker 3 (31:04):
Like it's the leader of the school is deliberately leading
them into the trap for you.
Speaker 1 (31:09):
Yeah, though not so much that it's like a trader fish,
but more than like it is this fish that a
like a legendary figure made a deal with that's sort
of thing. So yeah, this was a new one to
me as well. I don't think i'd heard this in
my previous trips to Hawaii. So and there may be
some more interesting partfish mythologies out there that I'll have
(31:30):
to turn up for the next episode.
Speaker 3 (31:33):
That's really interesting. I like it. As I promised earlier,
I wanted to come back and talk a bit more
about how parrotfish eat and a little bit about the
equipment they used to do it and what happens after
they do it after they eat. So one source I
was looking at here is a chapter in the Biology
(31:54):
of Parrotfishes by CRC Press twenty eighteen. And this chapter
was by Peter S. Wainwright and Samantha A. Price. It's
called Innovation and Diversity of the Feeding Mechanism in Parrotfishes.
And I'll probably come back to this in subsequent episodes
as well. But about the authors, Peter C. Wainwright is
a biologist at UC Davis and Samantha A. Price is
(32:15):
a biologist at Clemson, and so the authors here say
that how parrotfishes eat to the various species of parrotfish,
how they eat is quote one of the fundamental ecological
processes in coral reef ecosystems. So when you think about parrotfish,
you shouldn't just think of them as something you occasionally
(32:37):
see in a coral reef, but rather they are an
integral part of how coral reef ecosystems work, and kind
of the whole ecosystem doesn't really work without them. Now,
as we mentioned earlier, the feeding process of parrotfish involves
a lot of scraping and biting into hard stony materials.
(32:58):
Parrotfishes swim around coral reefs using their teeth to scrape
edible stuff off the outside of coral, and they break
off some coral and bring it along with them in
the process. Now, what is that edible stuff on the
outside of the coral. The authors say that it includes
primarily algae. Algae is a big part, but also detritis,
(33:20):
and in a marine context this usually means dead organic material,
so parts of dead organisms, fecal matter, all that yummy stuff.
Sometimes it will include bacteria, little colonies of bacteria, and
then they just say, quote a wide range of encrusting invertebrates,
so all kinds of little invertebrate animals that could be
(33:42):
found on a coral reef. This might include coral polyps themselves,
and it might also include things like sponges. Now, a
couple of sources I was looking at sort of classified
several different types of parrotfish feeding strategies, and the main
variation here seemed to be how how deep the parrotfish
would cut into the stony parts of the coral. So
(34:05):
you might have some that are referred to more as
browsers or grazers, that tend to typically just take the
soft parts off the surface of the coral. You've got
scrapers which scrape the coral a little harder and get
some of what's underneath. And then you've got what are
called excavators, which are really just taking chunks out of
the hard stuff. So the parrotfishes swim along on the reef,
(34:27):
scraping the stuff off with their outer teeth or excavating
bits of it and inevitably leaving scars on the rock
or the coral skeletons as they go. And then all
of this mixture of both hard and soft parts goes
into the mouth, where it is subjected to a second obstacle,
which is the trial of the inner jaws. Because parrotfishes
(34:50):
don't only have these fascinating outer teeth, they have a
second set of teeth at the back of their mouth,
known as the fyringeal jaw. Now you might have read
about pharyngeal jaws with respect to other animals that have them.
A number of fish and creatures that live in the
sea have them, and a well known example is the
(35:11):
more eel.
Speaker 1 (35:12):
That's right, Yeah, And of course, you know, those of
you who've watched any amount of science fiction, you might
also note that very angel jaws from in the world
of fictional monsters, we do have, of course, the alien xenomorph,
at least the main morph of the creature that we
see in those films, where we see this inner jaw
(35:33):
that functions as both a feeding mechanism and a puncturing weapon,
while elsewhere in the alien universe we see other morphs,
such as the deacon and the neo morph, that boast
extendable inner jaws rather than a secondary set of jaws.
But yeah, generally you often see some like comparative biology
write ups, and I think I've done right up to
(35:54):
this and this nature in the past, where when you're
comparing xenomorph physiology to the now world, the more a
eel is like a prime stopping point of comparison.
Speaker 3 (36:05):
Now, the exact design of the fyrngeal jaw in the
xenomorphos a little bit extra like. I'm not aware of
any examples in the in the natural world where like
the inner jaw comes out of the mouth and stabs
like a spear, like bites through the torso of a
prey animal. The inner jaws in the cases I'm aware of,
tend to stay mostly within the outer jaws, but they
(36:28):
do do something fascinating and perhaps to some horrifying. So
in the case of the more a eel, which is
a predator, the fyryngial jaw helps the eel capture and
swallow large live prey animals without allowing them to escape.
So the eel first bites the prey with its regular
outer jaws. These are the jaws you'd see, you know,
(36:49):
with the teeth. They have backward curving teeth, and those
the orientation of the teeth, the backward curving nature of
them helps them keep the keep the prey in place
without allowing it to back out and escape. And then
while the eel is holding the prey in place with
these outer jaws, the inner jaws reach up from out
(37:10):
of the eel's throat to bite the animal and pull
it further inside the mouth and down into the esophagus.
So it's a two step capture and conveyance mechanism. Now
just to stick with the more eel in a sidebar
for a second, I got interested in this. The evolutionary
reasoning for this is an interesting question. Apparently, most predatory
(37:33):
fish rely in large part on suction to capture and
swallow their prey. So these other fish use their muscles
to rapidly expand the mouth through the throat cavity, and
so when it expands like this, it creates a negative
pressure and it sucks in water from outside the mouth,
including the prey in that water. And this suction mechanism
(37:56):
can either be the action that pulls the prey into
the mouth in the first place, or it can also
be that after a predatory fish bites the prey with
its jaws, the suction mechanism then pulls the prey farther
into the mouth and down into the esophagus.
Speaker 1 (38:12):
Yeah, the scorpion fish is a great example of this,
and you can find some great video footage of this
where it's an ambush predator down there, hidden on the
floor of the sea, and then as its prey comes by,
it just kind of goes woomf and just rapidly sucks
it into its mouth and it's just gone like that.
And the scorpion fish is of course you'll note get
(38:32):
very robust looking, kind of frog ish looking, and that
is key here too, Right.
Speaker 3 (38:39):
So I was reading a two thousand and seven National
Science Foundation press release about research on moray eels published
in Nature that year, and the studies lead author, a
UC Davis scientist named Rita Meta, says that her study
found because of the way more eel bodies are shaped,
they're not able to generate much suction in the mouth cavity,
(39:02):
so instead they have this secondary set of jaws in
the throat. More eels are predators that often live in
coral reefs and they hide in little holes, gaps and
niches in the reef, and so a possible reason given
for this evolutionary difference why they have the feryngial jaws
instead of the suction mechanism is that by having pharyngeal jaws,
(39:25):
they can attack and swallow relatively large prey in tight,
confined little spaces where there would not be enough room
for them to expand the mouth or throat cavity to
create suction.
Speaker 1 (39:38):
Fascinating, it makes perfect sense.
Speaker 3 (39:41):
So that's an interesting idea, But I also think it's
an interesting parallel. You've got more eels and parrotfishes, which
are both coral reef dwellers and both have forryngial jaws,
but they use these inner jaws for totally different purposes. Again,
in the eel, it's to pull the prey down the
throat once it's in the mouth. Parrotfishes are again not
(40:02):
generally going to be chasing large live prey. They're mostly herbivores,
and they eat by scraping or gouging the coral and
getting stuff off the outside or in the layers underneath
the surface. This material that they scrape off of rocks
and coral, which mostly includes algae and other microbial organisms,
but also dead organic matter and coral skeleton bits, is
(40:25):
pulled down into the pharyngeal teeth where to quote Wainwright
and Price, it is quote mixed with mucus and ground
to a fine slurry before being passed to the intestines.
And Rob I was just looking up some photos of
parrotfish phyngeal teeth, and oh boy, what what are we
(40:45):
looking at here? These are some organs like they're clearly
specialized for grinding down this mixture of hard and soft
substances into a mucous, lubricated slurry. But some of these
pieces of parrotfish anatomy look like a car transmission gear
made out of bone. Others look like a bone pine cone.
(41:06):
It's it's interesting.
Speaker 1 (41:08):
Yeah, yeah, yeah, it does kind of look like interlocking
gear teeth.
Speaker 3 (41:13):
Yeah, it's crazy. So the digestive system extracts nutrients from
this slurry, and then the parrotfish excretes what is left over,
which is a big part of which is sand. Because
they're grinding down this coral. They bite off and scrape
off pieces of coral, grind up that coral with the
nightmare throat teeth, and then they poop sand. So I've
(41:37):
read it described that if you swim around with these buddies,
you will see them just like letting out kind of
poofs of sand or blasting clouds of sand into the
water column.
Speaker 1 (41:47):
Yeah. Absolutely, yeah, Like they're just they're kind of constantly
doing it. I mean, it makes sense. They're grazing and
they're kind of like goats, and they're kind of pooping
like goats, except it's coming out in this kind of
like puff of sand. And I know you included some
photos here where it's like more than a puff. It
looks like they're crop dusting. It's quite impressive.
Speaker 3 (42:08):
In fact, parrotfish poop so much sand. They are by
themselves a significant source of the bioroosion of coral and
a significant source of fine grained white sand in certain environments,
as in, when you are walking along a beautiful white
sand beach on some tropical island, there is a very
(42:31):
good chance a large proportion of the sand under your
feet is parrotfish poop.
Speaker 1 (42:37):
That's right. They are beach creation machines, and some of
the estimates for individual sand creation are quite stunning.
Speaker 3 (42:45):
Unbelievable to me. Actually, Like I had no idea about
this going in, So you might be thinking, yeah, how
much sand can these fish really poop? Again? It depends
where you are. There are obviously other sand creation mechanisms
in the sea, so this is not the only one.
But in some place parrotfish are responsible for a lot
of the sand that's there. One example I came across
(43:06):
is a paper in the journal Geology from twenty fifteen
by Perry at All called Linking reef Ecology to island building.
Parrotfish identified as major producers for island building sediment in
the Maldives and so again this is by Perry at All,
and so the Maldives Archipelago. This is an island chain
that contains approximately twelve hundred individual reef islands, which are
(43:30):
islands that are made entirely out of sediment that is
produced from underwater coral reefs. So the primary reason these
islands exist is that there are coral reef ecosystems on
an underwater platform. Of course, the reefs themselves are mostly
made up of the calcium carbonate skeletons of stony coral polyps,
(43:51):
and over time these coral reefs decompose into sediments like
sand and gravel. Parry at All right quote all coral
reef islands are inherently dependent on their surrounding reef habitats
not only because they provide the foundations for island development,
but also because they are the primary production sites for
the sediments necessary to sustain island building, growth and maintenance.
(44:15):
So without sediments from the coral reefs decomposing into sand
and gravel, you may not have an island here. But
the authors of this study say before their research, how
exactly that sediment is produced from the coral reef is
poorly quantified, so they investigated they're looking at where does
the sediment come from, and they used the example of Vakaru,
(44:39):
which is an interior reef island in the Maldives. They
found that the area around this island produces about six
hundred and eighty five thousand kilograms of sediment per year,
about seventy five percent of which comes from a place
they call the outer reef flat. So if you look
at the island from above, you'll see the part that
rises above water and is forested and has plants and
(45:01):
all that, the beach surrounding it, and then there's sort
of an inner lagoon and then an inner reef ring
and an outer reef ring. So most of the sediment
is coming from that outer ring of coral reef environments
in the water, about seventy five percent of the sediment
comes from the outer reef flat. Now within that outer reef,
(45:22):
which creates about seventy five percent of the island's yearly
supply of new sand, the author's discovered that more than
eighty five percent of the sand is produced by parrotfish.
And if you're curious what the second place was. The
runner up producer of reef sand in a distant second
place at about eight point eight percent in the outer
reef is a type of macroalgy called halimata, which makes
(45:47):
like calcified body parts and then those get shed and
eventually decompose a breakdown into sand. But almost all of
it is coming from what the parrotfish excrete. So parrotfish
are continually defecating this island into existence, and they remain
critical for maintaining its existence the author's right quote. The
(46:08):
generation of sediments suitable for maintaining this reef island is
thus critically dependent on a narrow zone of high productivity reef,
but most especially on the maintenance of healthy parrotfish populations
that can convert reef framework to sand grade sediment, and
so the parrotfish are crucial for the health of island
(46:29):
environments like this. But this is not just true of
these tiny coral reef islands that are generated from coral
reef sediments, even on many other coasts and larger islands,
where the island itself might be, you know, have other
geological explanations, like it's not just sand rising out of
the water. It might be a volcanic island or the
coast of a continent or something. In places where there
are coral reefs, beaches in many cases are still largely
(46:55):
parrotfish lavatory constructions. A figure sighted in several reputable looking sources,
though I couldn't find the exact origin of it, is
that around seventy percent of the sand on the White
Sandy Beaches of Hawaii is parrotfish excretion. It's hard to imagine,
like you're walking on a beach or even on a
(47:15):
whole island, and to imagine it having a biological fish
digestive system origin of this kind.
Speaker 1 (47:24):
I know, it's just it's crazy. It's one of those
mind blowing facts though that again, it gets pointed out
a lot when you are going to these places and snorkeling,
it becomes easy to sort of take for granted and
you have to sort of remind yourself. Then when you're
walking on the beach, it's like, no, for real, all
this sand and it's still kind of you know, beggars
(47:44):
the imagination.
Speaker 3 (47:46):
Yeah. Now, another thing that's interesting is that, of course
we know now that parrotfishes are very important for the
for creating the sand that in some cases makes it
possible to have an island and like these reef island
(48:06):
environments or helps replenish the beaches. But you might think,
on the other hand, well, the parrotfishes are the enemy
of the coral reefs though, because they're preying on, you know,
the coral. They're like scrape in the coral. In fact,
it is thought that parrotfishes help protect coral reefs because
as they're going along taking bites out of the barrel
(48:29):
coral reefs, they might be leaving scars in them, biting
pieces off, taking chunks out, But by grazing in this way,
they prevent the reefs from becoming overgrown by things like
algae and other encrusting invertebrates like sponges and stuff. So
they may eat some coral as they munch along, but
overall they keep the coral reefs healthy.
Speaker 1 (48:52):
That's right. This is a very important fact concerning like
necessary conservation for parrotfish because and it goes beyond that too,
Like I was reading that by constantly eating algae off
the coral. Again, they're constantly in doing this cleaning the coral,
creating new surfaces on the coral. And this is where
(49:13):
baby corals can attach and grow, so that's in play.
And on top of this, yeah, they're keeping like seaweed,
which remember is a microalgae. They're keeping seaweed growth in check.
And this is apparently one of the prime results of
parrotfish overfishing in parts of the Caribbean and the Pacific
seaweed overgrowth. And I was even reading this is from
(49:36):
Kramer at all. In twenty seventeen's prehistorical and historical declines
in Caribbean coral reef accretion rates driven by loss of parrotfish.
The authors here say that we see this connection proven
out in sediment fossils. There's a strong observable connection between
declines and coral accretion rates and parrotfish abundance. So and
(49:57):
it's more evidence that we need to conserve parrotfish in
order to help prevent coral reef environments from becoming quote,
algael dominated habitats. And yeah, so this is worth keeping
in mind. If you're traveling somewhere and parrotfish is on
the menu, it's advisable to eat something else. And indeed,
there are a number of efforts and protections in places
(50:19):
around the world to help protect these populations like the
parrotfish are a vital part of those coral environments which
are already threatened in a number of ways. This is
one that we can we can we can do a
lot to help coral reefs, but not eating parrotfish is
perhaps even more accessible than some of the things we
(50:40):
need to do to protect them.
Speaker 3 (50:42):
Now, there's one more brief thing I wanted to get
into before we wrap up part one here, and that
is about the material makeup of parrotfish teeth. I was
reading about this in a press release for the Lawrence
Berkeley National Laboratory. This was published in twenty seventeen. It's
called X raysor Reveal the Biting Truth about Parrotfish Teeth
(51:02):
by Glenn Roberts, Junior. And so this is talking about
research conducted at the Berkeley Lab, which used X rays
to examine parrotfish teeth and better understand what makes them
so resilient in the face of essentially scraping, biting, and
chewing on rocks all day. You know, on these these
coral skeletons are are not soft, you know, they're hard
(51:24):
calcium carbonate, and they're just these teeth are relentlessly munching.
So the particular parrotfish species in question was the steep
head parrotfish also known as the blunt head parrotfish scientific
name Chlorurus micro rhinos. And in this analysis, the researchers
found that the resilience of prot parrotfish teeth was due
(51:46):
to this woven microstructure of minerals in the enameloid of
the teeth, and the article compares it in fact in
structure to chain mail, which I thought was interesting. So this,
this microstructure creates a tooth the material that is incredibly
hard at the biting surface. The article points out that
(52:07):
the hardness of the biting surface is about five hundred
and thirty tons of pressure per square inch and they
compare this to the weight of eighty eight African elephants
on a single square inch of space. Now that microstructure
of the teeth fits into a larger structure, the sort
of morphology of the jaw, which is that these parrotfish
(52:30):
have like fifteen rows of teeth totaling about one thousand teeth,
all fused together, biologically glued or cemented together into this
single beak like structure, and the stiffness of the underlying
mineral crystals increases as it goes toward the tip the
biting surface. And the article quotes one of the researchers
(52:51):
involved named PUPA. Gilbert, who is a professor in the
physics department at the University of Wisconsin Madison, who says, quote,
fish teeth are the coolest biominerals of all. They are
the stiffest, among the hardest, and the most resistant to
fracture and to abrasion ever measured. And so given the
incredible material qualities of these parrotfish teeth and beaks, researchers
(53:15):
are looking into ways that the woven crystals of parrotfish
teeth might be used as an inspiration for human engineering,
a design pattern that could be reproduced in synthetic materials
to create a tougher, more resilient product.
Speaker 1 (53:29):
Now, just a couple of notes about these teeth for one.
On one hand, to come back to the alien xenomorph.
You know, it is interesting that they're sometimes described, at
least for some of the morphs, as possessing metal teeth,
and here we have the parrotfish, whose teeth are sometimes
described as being stronger than many metals metals, so it's
kind of interesting comparison there. Also, you know, inevitably there
(53:52):
is the question in the same way that we can't
look at a creature that is biting coral and you know,
think about our own teeth biting coral, we also can't
help but look at a creature with interesting teeth and
wonder what happens if I get bitten by one of these?
So I mean to be clear, you know, humans are
not on the menu for the parrotfish. There are accounts
(54:15):
of parrotfish rarely biting humans, though it does seem very rare,
and the incidents I was looking at, most of them
seem to be related to incidents with fishermen who were
actively harvesting them or you know, engaging with a trap
or something. But they have bitten humans before, so it
(54:35):
can happen. But I mean that can be said of
a lot of creatures, like you know, a horse can
bite you.
Speaker 3 (54:40):
Oh lord, why did I google this? But I did?
Speaker 1 (54:43):
Oh did you just google? You may have googled one
that comes up a lot.
Speaker 3 (54:47):
Came across a news article that claims to be a
photo of a wound from somebody who was bitten by
a parrotfish, and it looks it's grotesque. Listeners be warned.
Speaker 1 (55:00):
Yeah, there's a particular story that comes up in search
involving a fisherman, that is that was bitten in a
delicate area by one of these these parrotfish. So uh yeah,
I you know, weighed carefully if you decide to pursue these,
uh these stories for yourself. But yeah, it can happen,
it has happened, but uh, these are generally not considered
(55:21):
you know, risky fish, and people snorkel around them almost
constantly without issue.
Speaker 3 (55:27):
They're not looking to bite you. They're they're just trying
to go about their business. They're scraping.
Speaker 1 (55:32):
They're buzz't like bees, they have so much coral to scrape,
Like biting you takes time away from vital coral scraping time,
all right, well, we're gonna go and close up this
episode now, but we actually have even more exciting content
to cover about the parrotfish we didn't. We briefly mentioned their, their, their,
(55:53):
their sex changing ability, so we're going to get into
that for sure. Uh. There's also some other stuff that
will and I think in ways get us even closer
to that xenomorpha area again.
Speaker 3 (56:03):
So yeah, we're gonna have some cocoonings, some all kinds
of good stuff to get into next time.
Speaker 1 (56:08):
Yeah, yeah, so tune in for that. In the meantime,
I love to hear from anyone else out there who
has personal experience being around parrotfish. You know, we're not
encouraging anyone to actively seek out and eat parrotfish, but
you know, it has been a tradition of cuisines. So
if you would like to ride in and share your
culinary experience with parrotfish, If you have tasted a parrotfish liver, yes,
(56:32):
we would like to know what that is like that
We just would like to know. We'd like to know
what the Romans were into when they were consuming their
parrot fish meals. So write in. It's all fair game
as always, you know, if you have. When you do
write into us, you can always flag something is and
say hey, don't use my name on this, I want
it to be anonymous. Or you can say hey, this
(56:53):
is information for you, but don't actually read this. That's
fair as well. Just write in. We would love to
hear from you. Just a reminder that Stuff to Blow
Your Mind is primarily a science and culture podcast, with
core episodes on Tuesdays and Thursdays, listener mail on Mondays,
short form episode on Wednesdays, and on Fridays. We set
aside most serious concerns to just talk about a weird
film on Weird House Cinema.
Speaker 3 (57:13):
Huge thanks as always to our excellent audio producer JJ Posway.
If you would like to get in touch with us
with feedback on this episode or any other, to suggest
a topic for the future, or just to say hello,
you can email us at contact at stuff to Blow
your Mind dot com.
Speaker 2 (57:35):
Stuff to Blow Your Mind is production of iHeartRadio. For
more podcasts from My Heart Radio, visit the iHeartRadio app,
Apple Podcasts, or wherever you listen to your favorite shows. A. B.
Stuff To Blow Your Mind News
Hosts And Creators
Robert Lamb
Joe McCormick
Popular Podcasts
Are You A Charlotte?
In 1997, actress Kristin Davis’ life was forever changed when she took on the role of Charlotte York in Sex and the City. As we watched Carrie, Samantha, Miranda and Charlotte navigate relationships in NYC, the show helped push once unacceptable conversation topics out of the shadows and altered the narrative around women and sex. We all saw ourselves in them as they searched for fulfillment in life, sex and friendships. Now, Kristin Davis wants to connect with you, the fans, and share untold stories and all the behind the scenes. Together, with Kristin and special guests, what will begin with Sex and the City will evolve into talks about themes that are still so relevant today. "Are you a Charlotte?" is much more than just rewatching this beloved show, it brings the past and the present together as we talk with heart, humor and of course some optimism.
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com
Stuff You Should Know
If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.