July 1, 2025 • 46 mins
In this series of episodes from Stuff to Blow Your Mind, Robert and Joe discuss the majestic manta ray, from its biology and lifecycle to conservation issues and its portrayal in mythology, folk beliefs and even 1930s horror movies. Learn all about these strange and beautiful creatures and what’s being done to ensure their survival.
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Speaker 1 (00:03):
Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Speaker 2 (00:13):
Hey you welcome to Stuff to Blow Your Mind. My
name is Robert Lamb, and I am Joe McCormick. In
this episode, we're going to begin our look at the
manta ray because I very recently had the privilege to
travel with my family to Raja Ampat in Indonesia for
a week of snorkeling. And during that snorkeling, I got
(00:33):
to observe manta rays while in the water snorkeling, and
it was just a mind blowing experience. It was just magical.
I can't quite put it into words exactly, but it
was one of these situations where as I was snorkeling
out with the other snorkelers towards this manta ray cleaning station,
I found myself like mouthing, oh my god, oh my
God through my breathing apparatus.
Speaker 3 (00:55):
The cleaning station is that, do I understand right? That's
a place where they come to sort of be be
swarmed by fish that will help get parasites or other
kind of contaminants off of their bodies.
Speaker 2 (01:07):
Correct. This is this is pretty remarkable in its own right,
and I think we'll get into that more in the
second episode of this series. But yes, that's what we
were observing. These were some reef manta rays that had
come out to the cleaning station so that these various
fish could eat their parasites. And yeah, it was just
(01:27):
magical to watch these creatures move through the water like
some sort of animate black and white cape, you know,
some sort of an angel or demon, just something almost
beyond our ability to comprehend.
Speaker 3 (01:41):
It's a bach coming in on the organ as they
swish around.
Speaker 2 (01:44):
Yeah. Yeah, they're very, very dramatic, but also, as we'll
be discussing, relatively drama free at least as far as
what they're doing and what they're bringing to the table.
There's a lot of manta ray drama, but it's it's
almost entirely on us, the humans. Yeah. So I want
to mention up here at the top that we did
this snorkling at the Missoul Marine Reserve. This is also
(02:07):
where you find the Missoul Resort. The resort is just
one leg of the overall conservation mission here, which actually
started before the tourism part of the operation, like the
tourism part apparently was then built up afterwards to fund
the conservation mission, and I can't say enough good things
about this place. Founded on the side of a former
shark finning camp and in an area that had been
(02:29):
previously targeted by illegal lumber operations and dynamite fishing, and
now through the Missoul Foundation, they manage about three hundred
thousand acres or twelve two hundred square kilometers of marine
reserve with two distinct no take zones. They engage in
various conservation efforts, such as the Missoul Manta Program, a
(02:50):
reshark program, and this includes a program to reintroduce Indo
Pacific leopard sharks, and they partner with various organizations of
various like aquariums around the world old who have the
right eggs egg secs to reintroduce and their partners include
Atlanta's own Georgia Aquarium. They're also involved in coral reef restoration,
(03:11):
sustainability efforts in various community outreach and education programs.
Speaker 3 (03:15):
So you said you were doing a lot of snorkeling here.
I know y'all are a snorkeling family, right, I have
no experience with this.
Speaker 2 (03:22):
Yeah, yeah, my wife got us into it, and you know,
we'll go on snorkeling excursions here and there, and I
have to say, yeah, this is the best snorkeling of
my life thus far. This part of the world is
in what's known as the Coral Triangle. This is an
incredibly rich and diverse marine environment that happens to include,
(03:42):
according to the NOAA, quote, over six hundred reef building
coral species, seventy five percent of all species known to science,
three thousand species of reef fish, forty percent of the
world's coral reef species, and six of the world's seven
marine turtle species. Also three quarters of known molluscs.
Speaker 3 (04:00):
So it's happening.
Speaker 2 (04:01):
Yeah, it's yeah, just a very very rich place. And
you know, I'll no doubt come back to other things
I observed there in future episodes. But one of the
many highlights again was getting to observe these reef manta
rays in the wild. So we'll get back to the
details of the different the two main different manta species,
(04:22):
but this is the second largest of the rays and
one of only two possibly three extant manta ray species.
They can weigh up to fifteen hundred pounds or seven
hundred kilograms, and that's with a maximum disc width of
fifteen feet or four hundred and fifty centimeters if you were.
I guess you could sort of frame that as their
(04:44):
wingspan if you want.
Speaker 3 (04:45):
But you said, so, these are the reef mantas, and
the largest of the manta rays would be the giant
oceanic mantas.
Speaker 2 (04:52):
Correct. Yeah, and we'll come back to the stats on
them in a minute. But yeah, in both cases, great
bat like black and white creatures that seem to glide
and soar through the depths. And I think I had
observed some in the water while standing on a sandbar
elsewhere in the world previously, but this was my first
and only time getting to see them while in the water,
(05:14):
and again it was just astounding.
Speaker 3 (05:16):
So I have no experience with snorkeling, but in reading
up for this episode, I just kept coming across firsthand
descriptions again and again of how strange and amazing it
was to be in the water with manta rays. A
common thing these divers and researchers talk about is a
feeling of kind of intelligent or almost emotional connection with
(05:41):
the animal that they have not experienced with any other fish. Because,
to be clear, the manta is not like a mammal
like dolphins or whales might be that you might be
more you know, disposed, you might have more experience hearing
about these kind of connections people have with marine mammals.
But these are fish, you know, we think of them
as these very kind of cold creatures of limited intelligence,
(06:04):
kind of like sharks that seem to be mainly just
kind of machines acting on impulse. They don't have that
feeling of emotion and intelligence you might get from a mammal.
But in this case, this is a fish that lots
of people say, does it does have that feeling. It's
like it's there and it's alive and it's thinking.
Speaker 2 (06:23):
Yeah, this is a great point. And I think we'll
probably get into the intel, the brain, the intelligence of
the manta ray, especially in the next episode. But but
you do see this observation a lot. There seems to
be a curiosity on the part of the manta, and
in many ways, this kind of curiosity reminds us of
our interactions with mammalian marine species like dolphins and whales. Now,
(06:48):
in the case of our own experiences, I want to
stress that we observe them while snorkeling, rather than say
that we swam with them. I guess you could technically
say we swam them with them. We're in the same
button body of water with them, but we did keep
our distance. We did not chase the manta rays, and
we certainly did not attempt attempt to touch these gentle
giants of the sea.
Speaker 3 (07:10):
I assume that's discouraged.
Speaker 2 (07:11):
It is discouraged, yes, And in discussing this, like the
human desire to touch the manta ray, I wanted to
get into a preliminary discussion here about the human attitudes
toward the manta ray because this is important because ultimately
human attitudes towards the manta rays also plays into their
(07:33):
endangered status in the world, certainly with the oceanic man
manta so manta rays enjoy a pretty wide range. They're
found in warm, temperate, subtropical and tropical waters around the world.
As such, humans and coastal areas within their range have
known about them for a very long time. Hawaiian, Micronesian,
(07:54):
Southeast Asian, and South American traditions have viewed the manta
in varying supernatural life, as reincarnations of human souls, as
avatars of a creator deity, as divine protectors, as divine messengers,
and as such, they've even enjoyed traditional protected status amongst
certain groups, at least at different times. But there's also
(08:16):
a darker side to human attitudes toward manta rays. Over
the past couple of decades, the demand for manta ray
gill plates in traditional medicine, particularly traditional Chinese medicine, has
proven devastating for manta ray populations. Based on the unproven
and to be clear of pseudoscientific idea, the consumption of
these gills in some sort of like powdered driver and
(08:38):
or powdered form can boost the human immune system, among
other supposed benefits, and the story of how this is
really interesting in its own right. I was reading about
this in a paper by O'Malley at All titled characterization
of the Trade in Manta and Devil ray gill plates
in China and Southeast Asia through Trader Surveys, published in
(09:00):
twenty sixteen in Aquatic Conservation, Marine and Freshwater Ecosystems, and
they point out that mention of manta gill plates didn't
pop up in traditional Chinese medicine publications until around nineteen
seventy six. This to be clear, despite the fact that
traditional Chinese medicine itself is very very old, going back
(09:22):
like five thousand years, a widespread and popular form of
alternative medicine. But the consumption of these gill plates is
not some sort of deep seated tradition in this alternative
medicine practice.
Speaker 3 (09:38):
This would not be the only case that something is
presented as a traditional or ancient cure from some culture
or other when it is not. It is a fairly
recent thing people have started doing.
Speaker 2 (09:49):
Yeah. One of my key sources for these episodes is
twenty eighteen's Guide to the Manta and Devil Rays of
the World by Stevens, Fernando Dan, and Dyscaria. And in
this book, which I'll keep coming back to, they say
that this was all likely a quote clever marketing of
a readily available and cheap bycatch product. So, in other words,
(10:13):
various unsustainable fishing practices would be pulling mantas in any way,
and then they're like, well, let's market the parts of
this creature and sell it. And then as popularity builds,
it translates into direct targeting of mantas by what they
describe as boom and bust fisheries. So for reasons we'll
discuss in these episodes. These are vulnerable species that do
(10:35):
not easily endure this sort of targeted fishing, so these
operations inherently produce very short lived paydays while doing long
term damage to the populations. They also note that the
rise in popularity may also tie in with the rise
in human respiratory illnesses do in part to pollution, and
again these pseudoscientific claims. Basically, we're dealing with the idea that, Okay,
(10:58):
the these are filters for the fish, and therefore, on
some level, if I consume them, it's going to help
filter me out as well, it's going to protect me
from the things that would harm me in the environment.
So again, gill plates would seem to be a relatively
recent addition to traditional Chinese medicine and one that has
had a marked impact on the populations of these vulnerable
(11:22):
fish species. The reef manta is currently flagged as vulnerable,
while the giant oceanic manta is endangered.
Speaker 3 (11:29):
And I would imagine that we can come back to
this because I'm sure there's more nuance, but I would
imagine that they are especially vulnerable to heavy fishing and
harvesting because they're larger species that have a slower reproductive
schedule exactly.
Speaker 2 (11:53):
And then historically, on top of all of this, there
are Western European misconceptions and myths about manta and devil rays,
rooted apparently in the observations of sailors, but managing to
survive well into the early twentieth century and manifesting in
written fiction as well as in at least a couple
of early horror films.
Speaker 3 (12:14):
Yes, so, Rob, at your suggestion, I looked these up.
You sort of gave me an assignment here, and I
checked these movies out. Strangely, both of these made in
the nineteen thirties, you know, I think of the seventies
through the nineties as kind of the heyday of oh,
I don't know, killer Monster in the Ocean movies. Of course,
following Jaws, Jaws is the big one, and then you
get all the Jaws copycats, you know, Orca and everything
(12:36):
like that, and then even further down the chain into
like the real kind of Z grade copycats. You know,
in the nineties and two thousands there were just ten
billion direct to video shark movies made.
Speaker 2 (12:50):
Yeah, that's that is a great observation, especially since what
is it fifty years of jobs now celebrating a major birthday.
Speaker 3 (12:59):
But yeay, we I mean, you can't deny the power
of Jaws. Like, as much as I hate to contribute
to the demonizing of e ocean creatures, Jaws is just
a banger. It's a great movie.
Speaker 2 (13:08):
It is. It's a great film. It changed movies forever.
You can't talk about blockbusters without talking about Jaws. You
can't talk about monster movies really without talking about Jaws.
But it is interesting in pointing out that films like
Jaws arise in the nineteen seventies and then various other
creatures are drawn into the mix. But the seventies seem
(13:30):
to be the time period during which in the Europeans
in the West woke up to the idea that, oh yeah,
manta rays are fine. They're like absolutely not threatening anybody.
Not only are they not threatening, not actually threatening. It's
hard to conceive of them being threatening, Like, we can't
even think about making a monster movie about something so tame.
(13:50):
We'll make one about the killer rabbits first.
Speaker 3 (13:52):
I feel like the stuff you would get later, like
in the eighties is movies that had friendly aliens that
were basically manter ray shape. I can't even remember what
movie I'm thinking of, but I can picture it in
my mind, like a gentle, sort of illuminated, bioluminescent, floating
manta ray with intelligence. That's like communicating with a child
or something. Does that ring any bells for you who
(14:15):
that one?
Speaker 2 (14:15):
Not specifically, but I was reading doing some additional reading,
and there are various examples of creatures in sci fi
that say, live in the atmosphere of Jupiter. They're at
least partially based on the mantray. Oh, Like, it just
has a pleasing ethereal form. Again, it's like to the
point where it's almost hard for us to put ourselves
in the mindset of someone who sees a manta ray
(14:38):
and thinks about it as a relentless killer.
Speaker 3 (14:40):
Oh the Jupiter when you mentioned rang a bell because
we just talked about the story in our series on
the Great Storm the Big Red Spot of Jupiter, because
that was in a meeting with Medusa by Arthur C. Clark.
One of the aliens they meet there is like a
giant manta ray in the atmosphere of Jupiter. But anyway,
we got it, okay, So we got to talk about
these manta horror movies from the nineteenth thirties, neither of
(15:01):
which exactly lives up to that promise, but they're both
kind of marketed that way. So one of these movies
is called The Sea Bat Sea, not c the letter
Sea Bat Sea Bat From nineteen thirty This is a
pre code American romantic melodrama directed by Wesley Ruggles. Apparently,
(15:22):
in early production, Todd Browning was somehow attached to this,
and it was maybe supposed to be a vehicle featuring
Lon Cheney, but that never worked out. So this was
directed by Wesley Ruggles, shot in Mexico, starring Charles Bickford,
Raquel Torres, and Nil's Astor, and it even has Boris
Karloff in a small role. This came out a year
(15:43):
before Karloff's big break in Frankenstein that was thirty one.
So this is set on an island in the Caribbean
and the story follows a character named Nina played by
Mexican actress Raquel Torres, who is either in love with
or is the sister of, depending on which synopsis you read.
I was not able to watch this movie before recording today.
(16:05):
Is either in love with or is the sister of
a sponge diver named Carl. Sadly, Carl is killed when
his diving party is attacked by a dreaded local creature
known as the sea bat, and this is described in
some sources as a giant manta ray, in other sources
as a sting ray, which, as we'll discuss more throughout
(16:26):
the series, that those are not the same thing, though
some publications describing the movie seem not to recognize that
there is a difference. I think they just think, like
mantray's our stingrays same thing. In some effects shots, you
can see it really doesn't look like either. One rob
I put one screenshot in here for you. There are
shots of it underwater where it I don't know, it's
(16:48):
shaped kind of like an airplane or like a spaceship
of some kind. And then there are some shots where
you see it at the water line and it looks
just more like a giant shark or tuna type creature. Anyway,
After the tragic loss of Carl in this sea bat
related incident, the character Nina starts getting into voodoo and
(17:08):
then declares that she will marry any man who can
kill the dreaded sea bat. Several men try and fail
and then eventually a traveling preacher named Reverend Sims comes
to town. This is Charles Bickford, and he somehow both
converts Nina to Christianity. He leads her out of her
pact with Voodoo and falls in love with her. And
it's a tragic romance, I guess, or I don't know
(17:31):
how tragic. I think they do end up happily together
at the end. But there is a twist because it
turns out Reverend Sims is actually an escaped convict pretending
to be a minister. And then some of Nina's other
jealous suitors try to capture him and turn him in
for the bounty. But on the way there, they're like
on a boat, and the boat gets attacked by the
sea bat so they get sea batted, but Reverend Sims
(17:53):
survives and he goes back to Nina and they I
guess they live happily ever after. That's what I could
piece together reading various nazis online from the American Film
Institute Catalog's historical entry on the movie. I just wanted
to read a couple of production notes because they factor
into the Stingray or Manta Ray discussion quote. According to
(18:14):
the Telegraph News. The movie, with its crew of sixty
two personnel, was quote believed to be the largest motion
picture expedition to leave Hollywood for another American country. The
production required three pullmans and two baggage cars with two
hundred tons of equipment, and an inventory of articles taken
into Mexico under customs bond covered by more than one
(18:35):
thousand pages and showed a total value of eighty thousand dollars.
The article also claimed that the titular subject of the film,
the Giant Stingray, was filmed for the first time in
the sea bat.
Speaker 2 (18:48):
The giant stingray. Now, I'm not sure where that would
be that there is a giant freshwater stingray, but I
think this is a creature you find in touch tanks.
This is not in captivity. I don't think this is
something that is going to be that threatening.
Speaker 3 (19:03):
And once again, like I said, I couldn't watch the
whole movie, but in the clips I saw there were
two different ways the sea bat looked, and neither of
them looked like a real animal anyway.
Speaker 2 (19:15):
Not clear if.
Speaker 3 (19:16):
Anybody involved here knew the difference between a stingray and
a manta ray, which is rob Cee if you follow
me here, I think that's somewhat comparable to the difference
between like a great white shark and a whale shark,
like pretty different organisms. One's a filter feeder, the others
a predator, right right.
Speaker 2 (19:33):
And even then with the sting ray, I think there's
depending on what type of stingray, you have different forms
of feeding that are taking place.
Speaker 3 (19:39):
But yeah, essentially, many reviewers of Sea Bat also say
not enough Sea Bat. Sea Bat sequences are limited, and yeah,
so in the in the scene I did see of
it chasing the boat, it's like attacking the boat as
they're out on the water. It's basically Jaws. The creature
looks like a cross between kind of like a sting
ray but also like a and kind of a giant
(20:01):
silver tuna type thing. The other Killer Manta movie that
you flagged for me is The Devil Monster, which was
released in several different years. There was a nineteen thirty
six version, nineteen forty six version, also known as The
Sea Fiend. This is yet another production at least somewhat
marketed as ray horror, but it actually features relatively little
(20:24):
on screen ray action. So it was first made in
nineteen thirty six re edited and re released multiple times,
including in nineteen forty six when it was beefed up
with a bunch of exploitation content, which included footage of
what appears to be sadly genuine animal cruelty, like forcing
live animals to fight each other, and then also stock
(20:46):
documentary footage of native Pacific islanders just going about their
daily life included, no doubt, because this was a way
around Hayes Code prohibitions on nudity at the time. This
was directed by s Edwin Graham. The basic plot of
the nineteen forty six version is about a mission to
find a missing sailor whose ship was wrecked on the Galapagos,
(21:07):
though apparently huge stretches of the movie take a break
from the main narrative to just show octopus fights or
top topless women processing grain, and the climax has several
characters forced to battle a giant manta ray that is
said to be a threat to the local tuna fishermen.
So once again you got a monster manter ray the monster.
(21:29):
So I looked at this part where they're battling the ray,
and it does look much more clearly like a ray. Unfortunately,
I think in this case that's because it is a
real manta ray and the film's action climax is just
an unsimulated harpooning of a real animal.
Speaker 2 (21:44):
Oh well, that's quite unfortunate.
Speaker 3 (21:46):
So from a distance, I'm going to give a preemptive
thumbs down to both of these movies.
Speaker 2 (21:51):
Yeah, I don't think either of these are contenders for
weird house cinema treatment.
Speaker 3 (21:56):
Yeah, but it does raise this question, like because it's
framing them, framing rays as this monster that attacks humans
and you know, threatens boats and all. This was it
common before the modern era to view manta rays as
a kind of monster or at least a potentially dangerous animal,
like its cousins, the predatory sharks. And yes, I did
(22:18):
find evidence that this was just kind of common sailor's
lore that rays would, you know, could be dangerous, could
attack you, They might attack boats, they might attack divers.
One article I came across that was recounting some of
this folklore was from nineteen ten by the American biologist
Theodore Gill. It's called the Story of the Devilfish. That
(22:39):
name can be a little confusing because the term devilfish
or devil ray is still used today to refer to
a number of species within the genus Mobula, and that
is the genus to which the manta rays belong. Basically,
manta rays are the largest couple of species within the
genus Mobula, and then some of the other species within
(23:00):
the genus mobular are often called like devil rays or devilfish.
But the term, I think also is still sometimes used
to refer to just the rays in this geno more generally,
so I know that's confusing. I think the lore Gil
is talking about in this article probably does not observe
distinctions between devil rays and manta rays as we would
(23:21):
sort them today. It's probably just sailors are looking at
this thing's basically manta ray shaped. These things probably look
mostly the same to sailors. That's got you know, it's
got the wings, and it's got something that looks like
horns in the front, and it's big. So that's one
of these devilfish or devil rays. Gil in the beginning
of this article attests to common associations made between what
(23:42):
he calls the great ray and devils, vampires, and bats,
and he mentions that common names include the sea bat
like in the movie. And then concerning these associations with bats,
he's quoting another author named Holder, and he writes, quote
Holder thought that quote no more diabolical creature could be imagined.
(24:05):
They resembled enormous bats, and in following one another around
the circle, raised the outer tip of the long winglike
fin high out of the water in a graceful curve,
the other being deeply submerged. But then gil goes on
to say, quote another name for the monster ray has
been borrowed from the Spanish. Among the fishermen and especially
(24:26):
the pearl divers of Central America and western Mexico, it
is known as the manta. This is a Spanish term
meaning originally blanket, and was given by the fishermen in
parts of Spain and the island of Mallorca to a
species of the Mediterranean, and extended thence to similar fishes
of other regions. It has been explained that the name
(24:46):
was given by the Spaniards of America to the devilfish
because it was alleged to hover over and cover a
fisherman at the bottom as a blanket preparatory to killing
him for good. Indeed, that the devilfish may so attack
a man is not only widely spread, but of an
ancient origin. Such an idea, however, is contrary to our
(25:09):
knowledge of the fish. Like several other of the gigantic selations,
its diet is in almost inverse ratio to its size.
So already in nineteen ten, Theodore Gill is not going
for the lore that the rays fold down like a
death blanket over the divers to cover them on the
bottom and prepare them for death. But I did want
(25:30):
to say I think he is sort of onto something
when commenting about the idea of the diet being in
almost inverse ratio to its size. This is not like
a hard and fast rule. And there are very big
active predators that prey on large animals, But many of
the largest animals in the ocean, and the largest species
(25:50):
within different marine lineages, are filter feeders, feeding entirely on
tiny organisms and small bits of organic matter. And this
is true, of course of the giant oceanic manterray. Now
why would that be if you have a big filter
feeding surface and basically like a big kind of bowl
shaped mouth that functions like a sieve, and a big
(26:12):
body that can store a lot of energy for time
in between feeding booms. It can be an awesomely efficient
way to live, and with a large body yourself, you
don't need to worry a whole lot about predators. From
what I've been reading, the only real predators of the
giant oceanic manta rays are humans of course, and maybe
some toothed whales like orcas, and I think sharks may
(26:35):
sometimes bite them as well, but I understand sharks are
not major predators for giant mantas.
Speaker 2 (26:41):
Yeah, we'll come back to this, but basically that's the case,
but with some variations depending on exactly where in the
world you are, like the actually what the surrounding environment
is consisting of, and you know where the mantas are living.
Speaker 3 (26:55):
Yeah, so in general that there are a lot of
upsides to being a big filter feeding organism. If you're big,
you don't have to worry much about predators. You don't
have to be all that like fast or dangerous or anything.
You just kind of have to like cruise around with
a big filter feeding surface scoop in a lot of stuff,
just take it all in and get huge amounts of
biomass going straight into your metabolism and then store a
(27:18):
lot of it for later. That's another thing that people
often don't think about about the advantages of having a
big body biologically. You know, you think, well, it's good
to be bigger if you're in a fight. I mean
sometimes that's true, yes, but it's also just like you've
got a big freezer. Basically you can store a lot
of energy in that body.
Speaker 2 (27:36):
But of course a big part of this is in
doing this as an organism, you become a specialist.
Speaker 3 (27:40):
Right. So if you're a giant mantray and you come
across some divers in the water, I mean those divers
might be delicious, full of nutrition, but you just there's
nothing much you can do with them, Like, you don't
even have the tools really to eat that diver if
you wanted to.
Speaker 2 (27:54):
Yeah, that ship sailed long ago. Well, one can only
imagine that this is based on the fact that, of
course they're big, and it's natural for a human being
in the water outside of their element to be a
little spooked by large fish. I mean that's common, you kunter,
that's snorkeling. I feel, unless I know for certain what
I'm looking at, I would be a little nervous around
(28:16):
a large fish in the water. And then on top
of that, we have this we've already talked about how
there are observations of manta rays being curious concerning humans.
Manta rays more than devil rays, I'm to understand, but
that would of course add to it. If you're already
a little nervous around a big animal and it is
even halfway curious about you, that might also lead to
this kind of conclusion.
Speaker 3 (28:37):
Right. And while manta rays are very well known for
not being aggressive towards humans, I mean, it would still
be totally possible for one to just like injure you
by accident if you're getting too close. I mean they're
big animals, you know, yeah, and roll over, so like
you just you know, keep your distance.
Speaker 2 (28:52):
Yeah. And it's my understanding that as far as any
kind of like recorded accounts of even minor injuries concerning
manta rays and injuries to human beings, it's involved people
getting too close to them, trying to ride them, and
so forth, which you are not supposed to do.
Speaker 3 (29:08):
So despite their reputation as diabolical, but you know, vampire
bats of the sea or as some kind of underwater
death blanket. No giant mante rays or mante rays generally
devil rays as well, are generally not to be thought
of as a threat to humans, generally not very aggressive
and not anything to be all that concerned about. But
(29:28):
there is one other thing I came across in Gill's
article that really does paint a kind of scary picture,
not because of the ray doing anything threatening, but just
because of the sonic atmosphere it creates. And this is
Gil describing the experience of what it's like to be
around one of these giant rays jumping out of the water,
(29:48):
which they often do. So Gil writes, quote, it is
the great leaps out of the water that are most striking,
especially during the stillness of the night. Holder, on such
an a case on the outer Florida reef, first encountered
the fish, and then, quoting Holder, he says, quote, there
came out of the darkness near at hand, a rushing,
(30:08):
swishing noise, then a clap as of thunder, which seemed
to go roaring and reverberating away over the reef like
the discharge of a cannon. Not hard to imagine how
that could engender a sense of fear about this animal.
Speaker 2 (30:22):
Absolutely yeah. The authors of the Guide to Manta and
Devil Rays of the world, Steven said. All they mentioned
that if you're in the water when this happens, you
definitely feel it. So yeah, manta's and devils devil rays
all engage in leaping behavior like this, sometimes several meters
out of the water, and it's unknown exactly why they
do it, which I guess is similar to other fish
(30:44):
which we've talked about on the show in the past.
But the predominant theories involve either the dislodging of parasites,
and as we'll discuss and I think the next episode
we do on mantas, they geary a pretty large parasite load.
The other possibility is communication. The authors note that this
would mean there's much more to their social interaction than
is often thought. But the basic hypothesis here is that
(31:07):
these different mobilid species, especially the manta, they slap back
down on the surface of the water, and in doing
so they create a pressure wave this thunderclap that you
reference that could then be detected by other rays of
the same species miles away. Given that they're often observed
leaping before feeding, they could be alerting other mantas to
(31:30):
a feeding opportunity.
Speaker 3 (31:31):
Oh interesting, Okay.
Speaker 2 (31:33):
And why would they do that, because that's a lie.
Would you want to tell the other rays about all
this great food you just found, Well, the authors point out,
because food is plentiful, but the opportunity itself to feed
is fleeting, subject to the tides and so forth. So
the signal might be to bring in as many fellow
rays as possible, to engage in group feeding strategies, which
(31:55):
we'll get into in a bit here that also increase
individual food. So you know, let's all do it while
the getting's good. Let's all feed together and we'll all feast. Ah.
Speaker 3 (32:07):
Interesting, Okay.
Speaker 2 (32:08):
And then on top of that, some devil rays might
engage in breaching as a fitness signal for mating. But
again that's again that's a hypothesis based on just how
it seems to time with other things that they're doing
in the water. At any rate, as we giving back
to human sentiments about manta rays and the idea that
they're vampiric death blankets and so forth, Western sentiments seem
(32:30):
to turn in a major way during the nineteen seventies
despite the Jaws movies, with exposure to the reality that
manta rays are anything but the devilfish of a sailor's legend.
You know, they are the epitome of a gentle giant,
indifferent or even curious considering humans in the water, and
not aggressive at all. Again, I think the rare cases
(32:52):
you'll find of people being injured at all by a
manta are because they were intentionally trying to get way
too close to them as the harvesting of their gills goes.
Manta tourism has apparently been a major factor thus far
in the fight against this practice. People around the world
continue to spend a lot of money to observe manta
rays in the wild. In that twenty eighteen Guide to
(33:14):
the Man and Devil Rays of the World book, the
authors share that at the time of its publication, the
global estimate for direct revenue generated by manta tourism with
something like seventy three million annually, with associated tourism revenue
pushing that up to like one hundred and forty million annually.
So all of that basically translates to the realization that
(33:38):
if manta tourism is in the mix, a live manta
ray is worth far more than a dead one, and
so manti tourism, like a lot of marine tourism plays
an important role in manta conservation. At the same time,
of course, there's a careful balance there, right, because you
want people to be excited about the mantas. You want
people to come out and see the manta, spend money
on the mantas and thus helping to protect them. But
(34:01):
also you want to avoid detrimental side effects. You know
that can occur in a number of forms. You don't
want divers and snorkelers getting way too close to the animals.
You also don't want unsustainable practices at resorts and on
liver boards and so forth. You know, the ships are
going to take divers and snorkelers out to see these creatures.
(34:22):
You know, you have to walk that line, and I
think in my understanding is that everyone involved continues to
figure out exactly where that line falls. So at this point,
I thought we'd run through some basics about manta rays
(34:46):
and some associated devil rays to finish out this episode.
So mantis and devil rays belong to a group collectively
known as the Mobulids of the family mobili day zooming
out there rays of the order milio Batiforms, which contains
twelve families, three hundred and seventy species of rays, including
(35:07):
sting rays of various species. Moboloids are most closely related
to eagle rays and clown nose rays of this order,
which are bottom feeders. They sift for mollusks and crustaceans
on the seabed. Moboloids, however, have adapted to pelagic filter
feeding in the open water, similar to the evolutionary path
we see with like baleen whales and whale sharks, you know,
(35:31):
as we've been discussing, like specialize in feeding on all
the little things in the water. Eat the cloud if
you will, Yes, So they use their mouths and modified
gill plates in their filter feeding. The devil ray that
we've been discussing, these are much smaller. There are a
few different varieties, with the largest I believe being the
Chilean devil ray or sickle fin devil ray. It has
(35:53):
a maximum disc width of eleven point two feet or
three hundred and forty centimeters, and it can weigh up
to eight hundred and eighty two or four hundred kilograms.
The spinetail devil ray is also rather big. I mention
it because its scientific name is mobula mobular, which is
always fun. And again the reef manta ray Mobula alfredi,
(36:16):
which sounds delicious but it's not on the menu, comes
in at a maximum disc width of fifteen feet or
four hundred and fifty centimeters and a weight of fifteen
hundred pounds or seven hundred kilograms. But then again, the
oceanic manta is the biggest. That's Mobula birostras, and it
can reach a disc width of twenty three feet or
seven hundred centimeters and a weight of up to forty
(36:38):
four hundred pounds or two thousand kilograms. They are the
largest of all rays, and actually, i'm to understand, the
fifth largest fish. Period. There's also some argument to be
made for a possible third species of extent manta, a
Caribbean manta, closely related to the oceanic manta, only smaller now.
In addition to those gill plates, the other defining characteristics
(37:00):
of the mamboloids are their devil horns. That certainly seems
to lend to this idea that there's some sort of evil,
vampiric creature there. They're like bats, and then they have
devil horns. These are not horns, of course, These are
modified cephalic fins, So the rays use these special fins
to funnel plankton into their mouths during feeding. So the
(37:22):
gill plates that we were describing, these are supported by
five pairs of gill arches. You can see these when
you see some like wide mouth photographs of these various organisms,
and each species both slightly different gill plate structures to
capture particular target prey. We were talking about the ratio
between the size of the organism and the size of
(37:43):
the prey. Manta rays, the biggest, have gill plates evolved
to capture much smaller plectonic prey compared to various devil
ray species for example, they're going after the real small
stuff they're feeding. Is really interesting though, on top of this,
because their bodies are you know, think of them as
being largely flat, you know, they're kind of flattened out,
(38:03):
But as Stevens and co authors point out, during feeding quote,
their once flattened body and mouth becomes a giant black
hole with the pectoral fins serving as wings that power
the ray through the water, and then the gill plates
do the rest. So yeah, they expand out. They become
this like giant gaping maw to just consume all the
(38:25):
plankton they can get, and so that's the basic strategy.
Open your mouth really wide, use your cephalic fins to
help guide the food into the mouth, and then you know,
go in a straight line, just go straight through the food.
You know, eat the cloud. But that's just one of
eight and possibly nine different observed feeding strategies that you
(38:46):
see in rays, with only half of those being used
at least observed in devil rays. So I'm going to
roll through these because they're they're pretty interesting. Some some
are only slight variations based on the other ones. But
so first of all, you have straight feeding. So this
is usually horizontal, but sometimes it's vertical and the distance
depends on prey frequency. So you have a cloud of plankton,
(39:08):
a big school of plankedin or something. Well, you just
move straight through it, eat it, eat it up, swallow
it up, and then you do a one hundred and
eighty degree turn at the end and repeat as needed.
Number two this is manta's only apparently, and it's surface feeding.
So this is basically straight feeding, except right at the
surface of the water. All right, All right, now it
starts getting interesting. Chain feeding. So up to several dozen
(39:32):
individuals proceeding in a line feeding.
Speaker 3 (39:35):
Oh, it's funny that that would actually work. I would
imagine the further back you are in the line, maybe
you're not getting anything. But no, I wonder if going
through a head kind of creates a vortex, maybe that
sucks some more things in.
Speaker 2 (39:48):
I think that that might be what's happening. And also
we just have to remember we're dealing with an abundance
of food here and this ties in. This is exactly
and this is an example of the social feeding technique
group feed technique that they might hypothetically be calling other
mantas to engage in. Okay of next piggyback feeding. So
(40:10):
this is manta's only and it's actually only been observed
in reef mantas. So you'll have a smaller manta, usually
a male, and it finds a larger usually female, matches
her pace, and it's like stacked on top of her
and feeds as she's feeding in a straight line. And
sometimes you'll get additional mantas stacked on top of that
until the bottom most manta swims off and displaces the
(40:32):
whole stack. All right, Here's where it gets a little fancy.
Summer salt feeding. So this is where they're going in
a straight line, and then they'll do a three hundred
and sixty degree loop in the water while feeding, usually
just one or two loops out of straight feeding, but
they might do several dozen continuous summer salts, depending I
guess on how it's going for them and with the plankton.
(40:53):
This next one, though, this is where it gets. This
one gets crazy cyclone feeding. What Yeah, so this is
a parent reef mantas only at least as far as
observations go. And it begins as just a line of
chain feeding straight feeders. But then you know, something, something changes.
You know, maybe it's in just the how much planked
(41:14):
in their encountering. But the chain loops back on itself
to form a circle, and now we have a circle
of mantas feeding. And then more mantas begin to form
to join in and become part of the formation, and
so we end up with a counterclockwise cyclone that might
ultimately entail one hundred and fifty individuals and it might
(41:35):
even last up to an hour.
Speaker 3 (41:37):
Wow.
Speaker 2 (41:38):
And again the idea here seems to be that these
these group feeding scenarios when they're they're able to pull
them together like it actually results in a bounty for
everyone involved. On top of this, we have sideways feeding.
This is maybe not that fancy, it's just the manta
ray doing you know, chain feeding or straight feeding. But
(41:59):
on their side. Then we have bottom feeding, which I
guess you can think of as a return to form
feeding along the bottom like some of the other rays
that they're more distantly related to. And then a ninth
possible feeding technique that the authors here observe in devil
rays is what they call lunge feeding, and that's rapid
feeding acceleration into dense schools of prey. Again, this would
(42:23):
I think only be devil rays, which are going to
be the smaller of the species involved here. So mangoloods
first pop up in the fossil records some twenty eight
million years ago during the Middle Oligocene epoch, so according
to Stevens at All, they're among the most recently evolved
of the elasmo Bronx. This includes all sharks and battomorphs,
(42:46):
so you know sharks, rays, and so forth, the various
cartilage fish swimmers of the oceans. They've evolved to of
course become exceptional open water swimmers with sufficient speed bursts
up to a belief twenty miles per hour or thirty
three kilometers per hour. And this was interesting, And I
have trouble exactly understanding this how this works, but I
(43:11):
totally believe it. They say that they're flattened shapes apparently
make it more difficult for predators to bite onto them,
hold onto them, or certainly to target vital areas that way.
Speaker 3 (43:22):
Okay, Yeah, I wonder how that would work, because I
would imagine, you know, if you're kind of cookie shaped,
if you're flat, it might not be that hard to
take a bite of you. But I wonder if doing that,
you're maybe able to keep your most vital parts kind
of central, so if something does bite you, it gets
a less vital part of you.
Speaker 2 (43:40):
Yeah, like maybe you're more it's more possible that you
get a bite of a fin or wing, if you will. Yeah,
this is something they get get into in the book.
They do rapidly heal from serious injuries. The book displays
a few different rather dramatic examples via photograph of rays
(44:01):
with clear bites taken out of their fins, out of
their wings, and then a subsequent photo showing how those
like massive bites have mostly but you know, imperfectly healed
at a later observation date. And I mentioned this already,
but predation rates also seem to depend on particular communities
(44:21):
and environments. So, for example, the authors of this book
point out that mantis and Mozambique display far more evidence
of shark attacks compared to those in the Maldives, where
less than fifteen percent of mantis show evidence of bites.
Speaker 3 (44:33):
Yeah, I think I was specifically reading about off the
coast of Mozambique, where there was common evidence that mants
had been bitten by sharks but had survived the encounter
because they grew up and the wounds healed.
Speaker 2 (44:45):
Yeah, and the healing of those wounds also involves some
of the cleaning fish, which we'll get back to in
the next episode we do on mantas. All right, well,
we're going to go and close this episode of stuff
to blow your mind, but we're going to be back.
I don't think it's going to be the this week.
I think that's going to be next week based on
the way the schedule's coming together. But we'll be back
(45:05):
with at least one more episode on the manta Ray.
If not a couple, we'll just see how it comes together.
Just a reminder for everyone out there, The Stuff to
Blow Your Mind is a science and culture podcast with
core episodes on Tuesdays and Thursdays on Fridays. However, we
set aside most serious concerns to just talk about a
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(45:27):
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(45:48):
you get your episodes of podcasts.
Speaker 3 (45:50):
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 Stuff to Blow your
Mind dot com.
Speaker 1 (46:11):
Stuff to Blow Your Mind is production of iHeartRadio. For
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(46:38):
M
Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Speaker 2 (00:13):
Hey you welcome to Stuff to Blow Your Mind. My
name is Robert Lamb, and I am Joe McCormick. In
this episode, we're going to begin our look at the
manta ray because I very recently had the privilege to
travel with my family to Raja Ampat in Indonesia for
a week of snorkeling. And during that snorkeling, I got
(00:33):
to observe manta rays while in the water snorkeling, and
it was just a mind blowing experience. It was just magical.
I can't quite put it into words exactly, but it
was one of these situations where as I was snorkeling
out with the other snorkelers towards this manta ray cleaning station,
I found myself like mouthing, oh my god, oh my
God through my breathing apparatus.
Speaker 3 (00:55):
The cleaning station is that, do I understand right? That's
a place where they come to sort of be be
swarmed by fish that will help get parasites or other
kind of contaminants off of their bodies.
Speaker 2 (01:07):
Correct. This is this is pretty remarkable in its own right,
and I think we'll get into that more in the
second episode of this series. But yes, that's what we
were observing. These were some reef manta rays that had
come out to the cleaning station so that these various
fish could eat their parasites. And yeah, it was just
(01:27):
magical to watch these creatures move through the water like
some sort of animate black and white cape, you know,
some sort of an angel or demon, just something almost
beyond our ability to comprehend.
Speaker 3 (01:41):
It's a bach coming in on the organ as they
swish around.
Speaker 2 (01:44):
Yeah. Yeah, they're very, very dramatic, but also, as we'll
be discussing, relatively drama free at least as far as
what they're doing and what they're bringing to the table.
There's a lot of manta ray drama, but it's it's
almost entirely on us, the humans. Yeah. So I want
to mention up here at the top that we did
this snorkling at the Missoul Marine Reserve. This is also
(02:07):
where you find the Missoul Resort. The resort is just
one leg of the overall conservation mission here, which actually
started before the tourism part of the operation, like the
tourism part apparently was then built up afterwards to fund
the conservation mission, and I can't say enough good things
about this place. Founded on the side of a former
shark finning camp and in an area that had been
(02:29):
previously targeted by illegal lumber operations and dynamite fishing, and
now through the Missoul Foundation, they manage about three hundred
thousand acres or twelve two hundred square kilometers of marine
reserve with two distinct no take zones. They engage in
various conservation efforts, such as the Missoul Manta Program, a
(02:50):
reshark program, and this includes a program to reintroduce Indo
Pacific leopard sharks, and they partner with various organizations of
various like aquariums around the world old who have the
right eggs egg secs to reintroduce and their partners include
Atlanta's own Georgia Aquarium. They're also involved in coral reef restoration,
(03:11):
sustainability efforts in various community outreach and education programs.
Speaker 3 (03:15):
So you said you were doing a lot of snorkeling here.
I know y'all are a snorkeling family, right, I have
no experience with this.
Speaker 2 (03:22):
Yeah, yeah, my wife got us into it, and you know,
we'll go on snorkeling excursions here and there, and I
have to say, yeah, this is the best snorkeling of
my life thus far. This part of the world is
in what's known as the Coral Triangle. This is an
incredibly rich and diverse marine environment that happens to include,
(03:42):
according to the NOAA, quote, over six hundred reef building
coral species, seventy five percent of all species known to science,
three thousand species of reef fish, forty percent of the
world's coral reef species, and six of the world's seven
marine turtle species. Also three quarters of known molluscs.
Speaker 3 (04:00):
So it's happening.
Speaker 2 (04:01):
Yeah, it's yeah, just a very very rich place. And
you know, I'll no doubt come back to other things
I observed there in future episodes. But one of the
many highlights again was getting to observe these reef manta
rays in the wild. So we'll get back to the
details of the different the two main different manta species,
(04:22):
but this is the second largest of the rays and
one of only two possibly three extant manta ray species.
They can weigh up to fifteen hundred pounds or seven
hundred kilograms, and that's with a maximum disc width of
fifteen feet or four hundred and fifty centimeters if you were.
I guess you could sort of frame that as their
(04:44):
wingspan if you want.
Speaker 3 (04:45):
But you said, so, these are the reef mantas, and
the largest of the manta rays would be the giant
oceanic mantas.
Speaker 2 (04:52):
Correct. Yeah, and we'll come back to the stats on
them in a minute. But yeah, in both cases, great
bat like black and white creatures that seem to glide
and soar through the depths. And I think I had
observed some in the water while standing on a sandbar
elsewhere in the world previously, but this was my first
and only time getting to see them while in the water,
(05:14):
and again it was just astounding.
Speaker 3 (05:16):
So I have no experience with snorkeling, but in reading
up for this episode, I just kept coming across firsthand
descriptions again and again of how strange and amazing it
was to be in the water with manta rays. A
common thing these divers and researchers talk about is a
feeling of kind of intelligent or almost emotional connection with
(05:41):
the animal that they have not experienced with any other fish. Because,
to be clear, the manta is not like a mammal
like dolphins or whales might be that you might be
more you know, disposed, you might have more experience hearing
about these kind of connections people have with marine mammals.
But these are fish, you know, we think of them
as these very kind of cold creatures of limited intelligence,
(06:04):
kind of like sharks that seem to be mainly just
kind of machines acting on impulse. They don't have that
feeling of emotion and intelligence you might get from a mammal.
But in this case, this is a fish that lots
of people say, does it does have that feeling. It's
like it's there and it's alive and it's thinking.
Speaker 2 (06:23):
Yeah, this is a great point. And I think we'll
probably get into the intel, the brain, the intelligence of
the manta ray, especially in the next episode. But but
you do see this observation a lot. There seems to
be a curiosity on the part of the manta, and
in many ways, this kind of curiosity reminds us of
our interactions with mammalian marine species like dolphins and whales. Now,
(06:48):
in the case of our own experiences, I want to
stress that we observe them while snorkeling, rather than say
that we swam with them. I guess you could technically
say we swam them with them. We're in the same
button body of water with them, but we did keep
our distance. We did not chase the manta rays, and
we certainly did not attempt attempt to touch these gentle
giants of the sea.
Speaker 3 (07:10):
I assume that's discouraged.
Speaker 2 (07:11):
It is discouraged, yes, And in discussing this, like the
human desire to touch the manta ray, I wanted to
get into a preliminary discussion here about the human attitudes
toward the manta ray because this is important because ultimately
human attitudes towards the manta rays also plays into their
(07:33):
endangered status in the world, certainly with the oceanic man
manta so manta rays enjoy a pretty wide range. They're
found in warm, temperate, subtropical and tropical waters around the world.
As such, humans and coastal areas within their range have
known about them for a very long time. Hawaiian, Micronesian,
(07:54):
Southeast Asian, and South American traditions have viewed the manta
in varying supernatural life, as reincarnations of human souls, as
avatars of a creator deity, as divine protectors, as divine messengers,
and as such, they've even enjoyed traditional protected status amongst
certain groups, at least at different times. But there's also
(08:16):
a darker side to human attitudes toward manta rays. Over
the past couple of decades, the demand for manta ray
gill plates in traditional medicine, particularly traditional Chinese medicine, has
proven devastating for manta ray populations. Based on the unproven
and to be clear of pseudoscientific idea, the consumption of
these gills in some sort of like powdered driver and
(08:38):
or powdered form can boost the human immune system, among
other supposed benefits, and the story of how this is
really interesting in its own right. I was reading about
this in a paper by O'Malley at All titled characterization
of the Trade in Manta and Devil ray gill plates
in China and Southeast Asia through Trader Surveys, published in
(09:00):
twenty sixteen in Aquatic Conservation, Marine and Freshwater Ecosystems, and
they point out that mention of manta gill plates didn't
pop up in traditional Chinese medicine publications until around nineteen
seventy six. This to be clear, despite the fact that
traditional Chinese medicine itself is very very old, going back
(09:22):
like five thousand years, a widespread and popular form of
alternative medicine. But the consumption of these gill plates is
not some sort of deep seated tradition in this alternative
medicine practice.
Speaker 3 (09:38):
This would not be the only case that something is
presented as a traditional or ancient cure from some culture
or other when it is not. It is a fairly
recent thing people have started doing.
Speaker 2 (09:49):
Yeah. One of my key sources for these episodes is
twenty eighteen's Guide to the Manta and Devil Rays of
the World by Stevens, Fernando Dan, and Dyscaria. And in
this book, which I'll keep coming back to, they say
that this was all likely a quote clever marketing of
a readily available and cheap bycatch product. So, in other words,
(10:13):
various unsustainable fishing practices would be pulling mantas in any way,
and then they're like, well, let's market the parts of
this creature and sell it. And then as popularity builds,
it translates into direct targeting of mantas by what they
describe as boom and bust fisheries. So for reasons we'll
discuss in these episodes. These are vulnerable species that do
(10:35):
not easily endure this sort of targeted fishing, so these
operations inherently produce very short lived paydays while doing long
term damage to the populations. They also note that the
rise in popularity may also tie in with the rise
in human respiratory illnesses do in part to pollution, and
again these pseudoscientific claims. Basically, we're dealing with the idea that, Okay,
(10:58):
the these are filters for the fish, and therefore, on
some level, if I consume them, it's going to help
filter me out as well, it's going to protect me
from the things that would harm me in the environment.
So again, gill plates would seem to be a relatively
recent addition to traditional Chinese medicine and one that has
had a marked impact on the populations of these vulnerable
(11:22):
fish species. The reef manta is currently flagged as vulnerable,
while the giant oceanic manta is endangered.
Speaker 3 (11:29):
And I would imagine that we can come back to
this because I'm sure there's more nuance, but I would
imagine that they are especially vulnerable to heavy fishing and
harvesting because they're larger species that have a slower reproductive
schedule exactly.
Speaker 2 (11:53):
And then historically, on top of all of this, there
are Western European misconceptions and myths about manta and devil rays,
rooted apparently in the observations of sailors, but managing to
survive well into the early twentieth century and manifesting in
written fiction as well as in at least a couple
of early horror films.
Speaker 3 (12:14):
Yes, so, Rob, at your suggestion, I looked these up.
You sort of gave me an assignment here, and I
checked these movies out. Strangely, both of these made in
the nineteen thirties, you know, I think of the seventies
through the nineties as kind of the heyday of oh,
I don't know, killer Monster in the Ocean movies. Of course,
following Jaws, Jaws is the big one, and then you
get all the Jaws copycats, you know, Orca and everything
(12:36):
like that, and then even further down the chain into
like the real kind of Z grade copycats. You know,
in the nineties and two thousands there were just ten
billion direct to video shark movies made.
Speaker 2 (12:50):
Yeah, that's that is a great observation, especially since what
is it fifty years of jobs now celebrating a major birthday.
Speaker 3 (12:59):
But yeay, we I mean, you can't deny the power
of Jaws. Like, as much as I hate to contribute
to the demonizing of e ocean creatures, Jaws is just
a banger. It's a great movie.
Speaker 2 (13:08):
It is. It's a great film. It changed movies forever.
You can't talk about blockbusters without talking about Jaws. You
can't talk about monster movies really without talking about Jaws.
But it is interesting in pointing out that films like
Jaws arise in the nineteen seventies and then various other
creatures are drawn into the mix. But the seventies seem
(13:30):
to be the time period during which in the Europeans
in the West woke up to the idea that, oh yeah,
manta rays are fine. They're like absolutely not threatening anybody.
Not only are they not threatening, not actually threatening. It's
hard to conceive of them being threatening, Like, we can't
even think about making a monster movie about something so tame.
(13:50):
We'll make one about the killer rabbits first.
Speaker 3 (13:52):
I feel like the stuff you would get later, like
in the eighties is movies that had friendly aliens that
were basically manter ray shape. I can't even remember what
movie I'm thinking of, but I can picture it in
my mind, like a gentle, sort of illuminated, bioluminescent, floating
manta ray with intelligence. That's like communicating with a child
or something. Does that ring any bells for you who
(14:15):
that one?
Speaker 2 (14:15):
Not specifically, but I was reading doing some additional reading,
and there are various examples of creatures in sci fi
that say, live in the atmosphere of Jupiter. They're at
least partially based on the mantray. Oh, Like, it just
has a pleasing ethereal form. Again, it's like to the
point where it's almost hard for us to put ourselves
in the mindset of someone who sees a manta ray
(14:38):
and thinks about it as a relentless killer.
Speaker 3 (14:40):
Oh the Jupiter when you mentioned rang a bell because
we just talked about the story in our series on
the Great Storm the Big Red Spot of Jupiter, because
that was in a meeting with Medusa by Arthur C. Clark.
One of the aliens they meet there is like a
giant manta ray in the atmosphere of Jupiter. But anyway,
we got it, okay, So we got to talk about
these manta horror movies from the nineteenth thirties, neither of
(15:01):
which exactly lives up to that promise, but they're both
kind of marketed that way. So one of these movies
is called The Sea Bat Sea, not c the letter
Sea Bat Sea Bat From nineteen thirty This is a
pre code American romantic melodrama directed by Wesley Ruggles. Apparently,
(15:22):
in early production, Todd Browning was somehow attached to this,
and it was maybe supposed to be a vehicle featuring
Lon Cheney, but that never worked out. So this was
directed by Wesley Ruggles, shot in Mexico, starring Charles Bickford,
Raquel Torres, and Nil's Astor, and it even has Boris
Karloff in a small role. This came out a year
(15:43):
before Karloff's big break in Frankenstein that was thirty one.
So this is set on an island in the Caribbean
and the story follows a character named Nina played by
Mexican actress Raquel Torres, who is either in love with
or is the sister of, depending on which synopsis you read.
I was not able to watch this movie before recording today.
(16:05):
Is either in love with or is the sister of
a sponge diver named Carl. Sadly, Carl is killed when
his diving party is attacked by a dreaded local creature
known as the sea bat, and this is described in
some sources as a giant manta ray, in other sources
as a sting ray, which, as we'll discuss more throughout
(16:26):
the series, that those are not the same thing, though
some publications describing the movie seem not to recognize that
there is a difference. I think they just think, like
mantray's our stingrays same thing. In some effects shots, you
can see it really doesn't look like either. One rob
I put one screenshot in here for you. There are
shots of it underwater where it I don't know, it's
(16:48):
shaped kind of like an airplane or like a spaceship
of some kind. And then there are some shots where
you see it at the water line and it looks
just more like a giant shark or tuna type creature. Anyway,
After the tragic loss of Carl in this sea bat
related incident, the character Nina starts getting into voodoo and
(17:08):
then declares that she will marry any man who can
kill the dreaded sea bat. Several men try and fail
and then eventually a traveling preacher named Reverend Sims comes
to town. This is Charles Bickford, and he somehow both
converts Nina to Christianity. He leads her out of her
pact with Voodoo and falls in love with her. And
it's a tragic romance, I guess, or I don't know
(17:31):
how tragic. I think they do end up happily together
at the end. But there is a twist because it
turns out Reverend Sims is actually an escaped convict pretending
to be a minister. And then some of Nina's other
jealous suitors try to capture him and turn him in
for the bounty. But on the way there, they're like
on a boat, and the boat gets attacked by the
sea bat so they get sea batted, but Reverend Sims
(17:53):
survives and he goes back to Nina and they I
guess they live happily ever after. That's what I could
piece together reading various nazis online from the American Film
Institute Catalog's historical entry on the movie. I just wanted
to read a couple of production notes because they factor
into the Stingray or Manta Ray discussion quote. According to
(18:14):
the Telegraph News. The movie, with its crew of sixty
two personnel, was quote believed to be the largest motion
picture expedition to leave Hollywood for another American country. The
production required three pullmans and two baggage cars with two
hundred tons of equipment, and an inventory of articles taken
into Mexico under customs bond covered by more than one
(18:35):
thousand pages and showed a total value of eighty thousand dollars.
The article also claimed that the titular subject of the film,
the Giant Stingray, was filmed for the first time in
the sea bat.
Speaker 2 (18:48):
The giant stingray. Now, I'm not sure where that would
be that there is a giant freshwater stingray, but I
think this is a creature you find in touch tanks.
This is not in captivity. I don't think this is
something that is going to be that threatening.
Speaker 3 (19:03):
And once again, like I said, I couldn't watch the
whole movie, but in the clips I saw there were
two different ways the sea bat looked, and neither of
them looked like a real animal anyway.
Speaker 2 (19:15):
Not clear if.
Speaker 3 (19:16):
Anybody involved here knew the difference between a stingray and
a manta ray, which is rob Cee if you follow
me here, I think that's somewhat comparable to the difference
between like a great white shark and a whale shark,
like pretty different organisms. One's a filter feeder, the others
a predator, right right.
Speaker 2 (19:33):
And even then with the sting ray, I think there's
depending on what type of stingray, you have different forms
of feeding that are taking place.
Speaker 3 (19:39):
But yeah, essentially, many reviewers of Sea Bat also say
not enough Sea Bat. Sea Bat sequences are limited, and yeah,
so in the in the scene I did see of
it chasing the boat, it's like attacking the boat as
they're out on the water. It's basically Jaws. The creature
looks like a cross between kind of like a sting
ray but also like a and kind of a giant
(20:01):
silver tuna type thing. The other Killer Manta movie that
you flagged for me is The Devil Monster, which was
released in several different years. There was a nineteen thirty
six version, nineteen forty six version, also known as The
Sea Fiend. This is yet another production at least somewhat
marketed as ray horror, but it actually features relatively little
(20:24):
on screen ray action. So it was first made in
nineteen thirty six re edited and re released multiple times,
including in nineteen forty six when it was beefed up
with a bunch of exploitation content, which included footage of
what appears to be sadly genuine animal cruelty, like forcing
live animals to fight each other, and then also stock
(20:46):
documentary footage of native Pacific islanders just going about their
daily life included, no doubt, because this was a way
around Hayes Code prohibitions on nudity at the time. This
was directed by s Edwin Graham. The basic plot of
the nineteen forty six version is about a mission to
find a missing sailor whose ship was wrecked on the Galapagos,
(21:07):
though apparently huge stretches of the movie take a break
from the main narrative to just show octopus fights or
top topless women processing grain, and the climax has several
characters forced to battle a giant manta ray that is
said to be a threat to the local tuna fishermen.
So once again you got a monster manter ray the monster.
(21:29):
So I looked at this part where they're battling the ray,
and it does look much more clearly like a ray. Unfortunately,
I think in this case that's because it is a
real manta ray and the film's action climax is just
an unsimulated harpooning of a real animal.
Speaker 2 (21:44):
Oh well, that's quite unfortunate.
Speaker 3 (21:46):
So from a distance, I'm going to give a preemptive
thumbs down to both of these movies.
Speaker 2 (21:51):
Yeah, I don't think either of these are contenders for
weird house cinema treatment.
Speaker 3 (21:56):
Yeah, but it does raise this question, like because it's
framing them, framing rays as this monster that attacks humans
and you know, threatens boats and all. This was it
common before the modern era to view manta rays as
a kind of monster or at least a potentially dangerous animal,
like its cousins, the predatory sharks. And yes, I did
(22:18):
find evidence that this was just kind of common sailor's
lore that rays would, you know, could be dangerous, could
attack you, They might attack boats, they might attack divers.
One article I came across that was recounting some of
this folklore was from nineteen ten by the American biologist
Theodore Gill. It's called the Story of the Devilfish. That
(22:39):
name can be a little confusing because the term devilfish
or devil ray is still used today to refer to
a number of species within the genus Mobula, and that
is the genus to which the manta rays belong. Basically,
manta rays are the largest couple of species within the
genus Mobula, and then some of the other species within
(23:00):
the genus mobular are often called like devil rays or devilfish.
But the term, I think also is still sometimes used
to refer to just the rays in this geno more generally,
so I know that's confusing. I think the lore Gil
is talking about in this article probably does not observe
distinctions between devil rays and manta rays as we would
(23:21):
sort them today. It's probably just sailors are looking at
this thing's basically manta ray shaped. These things probably look
mostly the same to sailors. That's got you know, it's
got the wings, and it's got something that looks like
horns in the front, and it's big. So that's one
of these devilfish or devil rays. Gil in the beginning
of this article attests to common associations made between what
(23:42):
he calls the great ray and devils, vampires, and bats,
and he mentions that common names include the sea bat
like in the movie. And then concerning these associations with bats,
he's quoting another author named Holder, and he writes, quote
Holder thought that quote no more diabolical creature could be imagined.
(24:05):
They resembled enormous bats, and in following one another around
the circle, raised the outer tip of the long winglike
fin high out of the water in a graceful curve,
the other being deeply submerged. But then gil goes on
to say, quote another name for the monster ray has
been borrowed from the Spanish. Among the fishermen and especially
(24:26):
the pearl divers of Central America and western Mexico, it
is known as the manta. This is a Spanish term
meaning originally blanket, and was given by the fishermen in
parts of Spain and the island of Mallorca to a
species of the Mediterranean, and extended thence to similar fishes
of other regions. It has been explained that the name
(24:46):
was given by the Spaniards of America to the devilfish
because it was alleged to hover over and cover a
fisherman at the bottom as a blanket preparatory to killing
him for good. Indeed, that the devilfish may so attack
a man is not only widely spread, but of an
ancient origin. Such an idea, however, is contrary to our
(25:09):
knowledge of the fish. Like several other of the gigantic selations,
its diet is in almost inverse ratio to its size.
So already in nineteen ten, Theodore Gill is not going
for the lore that the rays fold down like a
death blanket over the divers to cover them on the
bottom and prepare them for death. But I did want
(25:30):
to say I think he is sort of onto something
when commenting about the idea of the diet being in
almost inverse ratio to its size. This is not like
a hard and fast rule. And there are very big
active predators that prey on large animals, But many of
the largest animals in the ocean, and the largest species
(25:50):
within different marine lineages, are filter feeders, feeding entirely on
tiny organisms and small bits of organic matter. And this
is true, of course of the giant oceanic manterray. Now
why would that be if you have a big filter
feeding surface and basically like a big kind of bowl
shaped mouth that functions like a sieve, and a big
(26:12):
body that can store a lot of energy for time
in between feeding booms. It can be an awesomely efficient
way to live, and with a large body yourself, you
don't need to worry a whole lot about predators. From
what I've been reading, the only real predators of the
giant oceanic manta rays are humans of course, and maybe
some toothed whales like orcas, and I think sharks may
(26:35):
sometimes bite them as well, but I understand sharks are
not major predators for giant mantas.
Speaker 2 (26:41):
Yeah, we'll come back to this, but basically that's the case,
but with some variations depending on exactly where in the
world you are, like the actually what the surrounding environment
is consisting of, and you know where the mantas are living.
Speaker 3 (26:55):
Yeah, so in general that there are a lot of
upsides to being a big filter feeding organism. If you're big,
you don't have to worry much about predators. You don't
have to be all that like fast or dangerous or anything.
You just kind of have to like cruise around with
a big filter feeding surface scoop in a lot of stuff,
just take it all in and get huge amounts of
biomass going straight into your metabolism and then store a
(27:18):
lot of it for later. That's another thing that people
often don't think about about the advantages of having a
big body biologically. You know, you think, well, it's good
to be bigger if you're in a fight. I mean
sometimes that's true, yes, but it's also just like you've
got a big freezer. Basically you can store a lot
of energy in that body.
Speaker 2 (27:36):
But of course a big part of this is in
doing this as an organism, you become a specialist.
Speaker 3 (27:40):
Right. So if you're a giant mantray and you come
across some divers in the water, I mean those divers
might be delicious, full of nutrition, but you just there's
nothing much you can do with them, Like, you don't
even have the tools really to eat that diver if
you wanted to.
Speaker 2 (27:54):
Yeah, that ship sailed long ago. Well, one can only
imagine that this is based on the fact that, of
course they're big, and it's natural for a human being
in the water outside of their element to be a
little spooked by large fish. I mean that's common, you kunter,
that's snorkeling. I feel, unless I know for certain what
I'm looking at, I would be a little nervous around
(28:16):
a large fish in the water. And then on top
of that, we have this we've already talked about how
there are observations of manta rays being curious concerning humans.
Manta rays more than devil rays, I'm to understand, but
that would of course add to it. If you're already
a little nervous around a big animal and it is
even halfway curious about you, that might also lead to
this kind of conclusion.
Speaker 3 (28:37):
Right. And while manta rays are very well known for
not being aggressive towards humans, I mean, it would still
be totally possible for one to just like injure you
by accident if you're getting too close. I mean they're
big animals, you know, yeah, and roll over, so like
you just you know, keep your distance.
Speaker 2 (28:52):
Yeah. And it's my understanding that as far as any
kind of like recorded accounts of even minor injuries concerning
manta rays and injuries to human beings, it's involved people
getting too close to them, trying to ride them, and
so forth, which you are not supposed to do.
Speaker 3 (29:08):
So despite their reputation as diabolical, but you know, vampire
bats of the sea or as some kind of underwater
death blanket. No giant mante rays or mante rays generally
devil rays as well, are generally not to be thought
of as a threat to humans, generally not very aggressive
and not anything to be all that concerned about. But
(29:28):
there is one other thing I came across in Gill's
article that really does paint a kind of scary picture,
not because of the ray doing anything threatening, but just
because of the sonic atmosphere it creates. And this is
Gil describing the experience of what it's like to be
around one of these giant rays jumping out of the water,
(29:48):
which they often do. So Gil writes, quote, it is
the great leaps out of the water that are most striking,
especially during the stillness of the night. Holder, on such
an a case on the outer Florida reef, first encountered
the fish, and then, quoting Holder, he says, quote, there
came out of the darkness near at hand, a rushing,
(30:08):
swishing noise, then a clap as of thunder, which seemed
to go roaring and reverberating away over the reef like
the discharge of a cannon. Not hard to imagine how
that could engender a sense of fear about this animal.
Speaker 2 (30:22):
Absolutely yeah. The authors of the Guide to Manta and
Devil Rays of the world, Steven said. All they mentioned
that if you're in the water when this happens, you
definitely feel it. So yeah, manta's and devils devil rays
all engage in leaping behavior like this, sometimes several meters
out of the water, and it's unknown exactly why they
do it, which I guess is similar to other fish
(30:44):
which we've talked about on the show in the past.
But the predominant theories involve either the dislodging of parasites,
and as we'll discuss and I think the next episode
we do on mantas, they geary a pretty large parasite load.
The other possibility is communication. The authors note that this
would mean there's much more to their social interaction than
is often thought. But the basic hypothesis here is that
(31:07):
these different mobilid species, especially the manta, they slap back
down on the surface of the water, and in doing
so they create a pressure wave this thunderclap that you
reference that could then be detected by other rays of
the same species miles away. Given that they're often observed
leaping before feeding, they could be alerting other mantas to
(31:30):
a feeding opportunity.
Speaker 3 (31:31):
Oh interesting, Okay.
Speaker 2 (31:33):
And why would they do that, because that's a lie.
Would you want to tell the other rays about all
this great food you just found, Well, the authors point out,
because food is plentiful, but the opportunity itself to feed
is fleeting, subject to the tides and so forth. So
the signal might be to bring in as many fellow
rays as possible, to engage in group feeding strategies, which
(31:55):
we'll get into in a bit here that also increase
individual food. So you know, let's all do it while
the getting's good. Let's all feed together and we'll all feast. Ah.
Speaker 3 (32:07):
Interesting, Okay.
Speaker 2 (32:08):
And then on top of that, some devil rays might
engage in breaching as a fitness signal for mating. But
again that's again that's a hypothesis based on just how
it seems to time with other things that they're doing
in the water. At any rate, as we giving back
to human sentiments about manta rays and the idea that
they're vampiric death blankets and so forth, Western sentiments seem
(32:30):
to turn in a major way during the nineteen seventies
despite the Jaws movies, with exposure to the reality that
manta rays are anything but the devilfish of a sailor's legend.
You know, they are the epitome of a gentle giant,
indifferent or even curious considering humans in the water, and
not aggressive at all. Again, I think the rare cases
(32:52):
you'll find of people being injured at all by a
manta are because they were intentionally trying to get way
too close to them as the harvesting of their gills goes.
Manta tourism has apparently been a major factor thus far
in the fight against this practice. People around the world
continue to spend a lot of money to observe manta
rays in the wild. In that twenty eighteen Guide to
(33:14):
the Man and Devil Rays of the World book, the
authors share that at the time of its publication, the
global estimate for direct revenue generated by manta tourism with
something like seventy three million annually, with associated tourism revenue
pushing that up to like one hundred and forty million annually.
So all of that basically translates to the realization that
(33:38):
if manta tourism is in the mix, a live manta
ray is worth far more than a dead one, and
so manti tourism, like a lot of marine tourism plays
an important role in manta conservation. At the same time,
of course, there's a careful balance there, right, because you
want people to be excited about the mantas. You want
people to come out and see the manta, spend money
on the mantas and thus helping to protect them. But
(34:01):
also you want to avoid detrimental side effects. You know
that can occur in a number of forms. You don't
want divers and snorkelers getting way too close to the animals.
You also don't want unsustainable practices at resorts and on
liver boards and so forth. You know, the ships are
going to take divers and snorkelers out to see these creatures.
(34:22):
You know, you have to walk that line, and I
think in my understanding is that everyone involved continues to
figure out exactly where that line falls. So at this point,
I thought we'd run through some basics about manta rays
(34:46):
and some associated devil rays to finish out this episode.
So mantis and devil rays belong to a group collectively
known as the Mobulids of the family mobili day zooming
out there rays of the order milio Batiforms, which contains
twelve families, three hundred and seventy species of rays, including
(35:07):
sting rays of various species. Moboloids are most closely related
to eagle rays and clown nose rays of this order,
which are bottom feeders. They sift for mollusks and crustaceans
on the seabed. Moboloids, however, have adapted to pelagic filter
feeding in the open water, similar to the evolutionary path
we see with like baleen whales and whale sharks, you know,
(35:31):
as we've been discussing, like specialize in feeding on all
the little things in the water. Eat the cloud if
you will, Yes, So they use their mouths and modified
gill plates in their filter feeding. The devil ray that
we've been discussing, these are much smaller. There are a
few different varieties, with the largest I believe being the
Chilean devil ray or sickle fin devil ray. It has
(35:53):
a maximum disc width of eleven point two feet or
three hundred and forty centimeters, and it can weigh up
to eight hundred and eighty two or four hundred kilograms.
The spinetail devil ray is also rather big. I mention
it because its scientific name is mobula mobular, which is
always fun. And again the reef manta ray Mobula alfredi,
(36:16):
which sounds delicious but it's not on the menu, comes
in at a maximum disc width of fifteen feet or
four hundred and fifty centimeters and a weight of fifteen
hundred pounds or seven hundred kilograms. But then again, the
oceanic manta is the biggest. That's Mobula birostras, and it
can reach a disc width of twenty three feet or
seven hundred centimeters and a weight of up to forty
(36:38):
four hundred pounds or two thousand kilograms. They are the
largest of all rays, and actually, i'm to understand, the
fifth largest fish. Period. There's also some argument to be
made for a possible third species of extent manta, a
Caribbean manta, closely related to the oceanic manta, only smaller now.
In addition to those gill plates, the other defining characteristics
(37:00):
of the mamboloids are their devil horns. That certainly seems
to lend to this idea that there's some sort of evil,
vampiric creature there. They're like bats, and then they have
devil horns. These are not horns, of course, These are
modified cephalic fins, So the rays use these special fins
to funnel plankton into their mouths during feeding. So the
(37:22):
gill plates that we were describing, these are supported by
five pairs of gill arches. You can see these when
you see some like wide mouth photographs of these various organisms,
and each species both slightly different gill plate structures to
capture particular target prey. We were talking about the ratio
between the size of the organism and the size of
(37:43):
the prey. Manta rays, the biggest, have gill plates evolved
to capture much smaller plectonic prey compared to various devil
ray species for example, they're going after the real small
stuff they're feeding. Is really interesting though, on top of this,
because their bodies are you know, think of them as
being largely flat, you know, they're kind of flattened out,
(38:03):
But as Stevens and co authors point out, during feeding quote,
their once flattened body and mouth becomes a giant black
hole with the pectoral fins serving as wings that power
the ray through the water, and then the gill plates
do the rest. So yeah, they expand out. They become
this like giant gaping maw to just consume all the
(38:25):
plankton they can get, and so that's the basic strategy.
Open your mouth really wide, use your cephalic fins to
help guide the food into the mouth, and then you know,
go in a straight line, just go straight through the food.
You know, eat the cloud. But that's just one of
eight and possibly nine different observed feeding strategies that you
(38:46):
see in rays, with only half of those being used
at least observed in devil rays. So I'm going to
roll through these because they're they're pretty interesting. Some some
are only slight variations based on the other ones. But
so first of all, you have straight feeding. So this
is usually horizontal, but sometimes it's vertical and the distance
depends on prey frequency. So you have a cloud of plankton,
(39:08):
a big school of plankedin or something. Well, you just
move straight through it, eat it, eat it up, swallow
it up, and then you do a one hundred and
eighty degree turn at the end and repeat as needed.
Number two this is manta's only apparently, and it's surface feeding.
So this is basically straight feeding, except right at the
surface of the water. All right, All right, now it
starts getting interesting. Chain feeding. So up to several dozen
(39:32):
individuals proceeding in a line feeding.
Speaker 3 (39:35):
Oh, it's funny that that would actually work. I would
imagine the further back you are in the line, maybe
you're not getting anything. But no, I wonder if going
through a head kind of creates a vortex, maybe that
sucks some more things in.
Speaker 2 (39:48):
I think that that might be what's happening. And also
we just have to remember we're dealing with an abundance
of food here and this ties in. This is exactly
and this is an example of the social feeding technique
group feed technique that they might hypothetically be calling other
mantas to engage in. Okay of next piggyback feeding. So
(40:10):
this is manta's only and it's actually only been observed
in reef mantas. So you'll have a smaller manta, usually
a male, and it finds a larger usually female, matches
her pace, and it's like stacked on top of her
and feeds as she's feeding in a straight line. And
sometimes you'll get additional mantas stacked on top of that
until the bottom most manta swims off and displaces the
(40:32):
whole stack. All right, Here's where it gets a little fancy.
Summer salt feeding. So this is where they're going in
a straight line, and then they'll do a three hundred
and sixty degree loop in the water while feeding, usually
just one or two loops out of straight feeding, but
they might do several dozen continuous summer salts, depending I
guess on how it's going for them and with the plankton.
(40:53):
This next one, though, this is where it gets. This
one gets crazy cyclone feeding. What Yeah, so this is
a parent reef mantas only at least as far as
observations go. And it begins as just a line of
chain feeding straight feeders. But then you know, something, something changes.
You know, maybe it's in just the how much planked
(41:14):
in their encountering. But the chain loops back on itself
to form a circle, and now we have a circle
of mantas feeding. And then more mantas begin to form
to join in and become part of the formation, and
so we end up with a counterclockwise cyclone that might
ultimately entail one hundred and fifty individuals and it might
(41:35):
even last up to an hour.
Speaker 3 (41:37):
Wow.
Speaker 2 (41:38):
And again the idea here seems to be that these
these group feeding scenarios when they're they're able to pull
them together like it actually results in a bounty for
everyone involved. On top of this, we have sideways feeding.
This is maybe not that fancy, it's just the manta
ray doing you know, chain feeding or straight feeding. But
(41:59):
on their side. Then we have bottom feeding, which I
guess you can think of as a return to form
feeding along the bottom like some of the other rays
that they're more distantly related to. And then a ninth
possible feeding technique that the authors here observe in devil
rays is what they call lunge feeding, and that's rapid
feeding acceleration into dense schools of prey. Again, this would
(42:23):
I think only be devil rays, which are going to
be the smaller of the species involved here. So mangoloods
first pop up in the fossil records some twenty eight
million years ago during the Middle Oligocene epoch, so according
to Stevens at All, they're among the most recently evolved
of the elasmo Bronx. This includes all sharks and battomorphs,
(42:46):
so you know sharks, rays, and so forth, the various
cartilage fish swimmers of the oceans. They've evolved to of
course become exceptional open water swimmers with sufficient speed bursts
up to a belief twenty miles per hour or thirty
three kilometers per hour. And this was interesting, And I
have trouble exactly understanding this how this works, but I
(43:11):
totally believe it. They say that they're flattened shapes apparently
make it more difficult for predators to bite onto them,
hold onto them, or certainly to target vital areas that way.
Speaker 3 (43:22):
Okay, Yeah, I wonder how that would work, because I
would imagine, you know, if you're kind of cookie shaped,
if you're flat, it might not be that hard to
take a bite of you. But I wonder if doing that,
you're maybe able to keep your most vital parts kind
of central, so if something does bite you, it gets
a less vital part of you.
Speaker 2 (43:40):
Yeah, like maybe you're more it's more possible that you
get a bite of a fin or wing, if you will. Yeah,
this is something they get get into in the book.
They do rapidly heal from serious injuries. The book displays
a few different rather dramatic examples via photograph of rays
(44:01):
with clear bites taken out of their fins, out of
their wings, and then a subsequent photo showing how those
like massive bites have mostly but you know, imperfectly healed
at a later observation date. And I mentioned this already,
but predation rates also seem to depend on particular communities
(44:21):
and environments. So, for example, the authors of this book
point out that mantis and Mozambique display far more evidence
of shark attacks compared to those in the Maldives, where
less than fifteen percent of mantis show evidence of bites.
Speaker 3 (44:33):
Yeah, I think I was specifically reading about off the
coast of Mozambique, where there was common evidence that mants
had been bitten by sharks but had survived the encounter
because they grew up and the wounds healed.
Speaker 2 (44:45):
Yeah, and the healing of those wounds also involves some
of the cleaning fish, which we'll get back to in
the next episode we do on mantas. All right, well,
we're going to go and close this episode of stuff
to blow your mind, but we're going to be back.
I don't think it's going to be the this week.
I think that's going to be next week based on
the way the schedule's coming together. But we'll be back
(45:05):
with at least one more episode on the manta Ray.
If not a couple, we'll just see how it comes together.
Just a reminder for everyone out there, The Stuff to
Blow Your Mind is a science and culture podcast with
core episodes on Tuesdays and Thursdays on Fridays. However, we
set aside most serious concerns to just talk about a
weird film on Weird House Cinema. Wherever you get the podcast,
we just ask the you rate and review us, give
(45:27):
us a few stars. That helps us out. And if
you want to follow us on social media, let's see
we're stbim Podcasts on Instagram. That our more recent Instagram
account that we're still trying to build back up. Let's see.
If you want to follow a Weird House Cinema that
we are on Letterboxed, we are Weird House on that platform.
And yeah, you can. Otherwise, just get the podcast wherever
(45:48):
you get your episodes of podcasts.
Speaker 3 (45:50):
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 Stuff to Blow your
Mind dot com.
Speaker 1 (46:11):
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're listening to your favorite shows.
(46:38):
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