Sharks of Summer (with Marah Hardt of ‘Sex in the Sea’)

If you watch enough 'Jaws' and Shark Week, you’re bound to see sharks as ravenous death machines. But is it really more appropriate to think of these ancient creatures as LIFE machines? In this episode of the Stuff to Blow Your Mind podcast, Robert and Christian welcome 'Sex in the Sea' author Marah Hardt back on the podcast for a discussion of embryonic cannibalism, virgin shark birth, conservation efforts and more.

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Episode Transcript

Speaker 1 (00:03):
Welcome to Stuff to Blow your Mind from how Stuff
Works dot com. Hey you welcome to stuff to Blow
your mind. My name is Robert Lamb and I'm Christian Sager,
So Robert. When I was five years old, I made
a huge mistake. I thought it would be a good
idea to read Peter Benchley's novel Jaws while I was

(00:27):
on vacation with my family on Cape Cod in Massachusetts,
which is generally where Jaws is supposed to be set.
I think, what do they call it in the movie?
Is it amity? Something like that? I believe so, yes, yeah,
So I was terrified of going in the ocean the
entire time that I was visiting the family there, and
my father's side of the family, they're all, you know,

(00:49):
ocean dwellers. Basically, they're like fisherman and they wanted to
go out and go out on the boat and do
fishing and stuff. And I was just terrified the whole time,
like I wouldn't get in the water. Uh. And it
was a big mistake. So sharks have been scary to
me for a long time. I think Just three D
was the first scary shark movie that I ever saw.

(01:11):
What about You, Oh, you know, I can't remember when
I Jaws was one of those films that since they
played it on TV all the time, I think I
just absorbed it long before I ever actually gave it
a start to finish viewing. But on top of that,
I feel like my life has been filled with just
absorption of of multiple bad shark movies over the years.

(01:35):
You know, um, most of them Jaws knockoffs, because there's
just a tremendous wealth of of terrible often like Italian
and Spanish Jaws rip offs, and there's there's a lot
of interesting stuff going on there because in this episode,
as we talk about sharks, and as we uh we
talked to Mara Heart, author of Sex in the Sea

(01:56):
about sharks, when get into shark conservation and Shark Week
and and these other issues, you know, we talk about
how we villainize them and we focus on their ferocious nature,
and certainly all of these monster movies do that. But
then you also you get into this idea of like
what are we what are we doing with these shark stories,
like is there this there's this weird kind of um

(02:17):
like fetishization of giant uh see carnivores like eating bikini women.
I've I've I've always find it like strangely perverse. Yeah,
there is a weird thing going on there. I wonder
if you can trace the origin of that back to
the creature of the Black Lagoon. Maybe that's another episode,
but there is a fascination with like predatory underwater creatures

(02:43):
eating human women for some reason. But I want to
point out, though, we do this thing outside of the
podcast that not all of our listeners know about called
Trailer Talk, where once a week we go on Facebook
Live you Me and Joe, and we put together a
bunch of trailers from usually bad horror movies or sci
fi movies across the years related to whatever topic we're

(03:06):
talking about on the podcast that week. Man, we're gonna
have fun with this one, because there's a whole Wicki
entry just on killer Shark films and it's like fifty films. Yeah,
it's it's insane how many. Again, most of these are
really essentially just Jaws knockoffs and they just made one
after the other, just add nauseam, and most of them

(03:28):
do not have a creative idea added to. Occasionally you're
not across the film, like I believe it's what Lucio
fool see Zombie where you have that wonderful scene where
a zombie fights a shark underwater. I seen that. We'll
have to one. We'll have to work with with Ramsey,
our producer on that too, to edit it because I
think there's a little Nudi in that one, because like

(03:48):
because it's a shark fighting a zombie and there's like
a topless lady swimming. Geez. This is the This is
the level of cinematic uh Art. That deal the one
that I always think of that's not Jaws, that I
always keep returning to, and I know it's a favorite
of Joe's because he talks about it a lot. Is
Deep Blue Sea. It's got that fabulous l O cool

(04:10):
j music video connected to it. But it also stars
my favorite sci fi heart throb that we've talked about
on the show before, Thomas Jane. Oh yeah he uh
if I remember correctly, he perfects a method for swimming
with sharks where he like grabs their fins and rides them.
It is very weird. We should rewatch that for the

(04:32):
for the Facebook Life, but for today's episode, really, what
our focus is going to be on is the opposite
of these Killer Shark movies, and that's what we end
up talking tomorrow about, is that really, while we've fetishized
these sharks as killing machines, they're more life machines than
anything else. They have a variety of ways of reproducing

(04:55):
and making sure that their genetic heritage is passed on. Indeed,
I mean, there's just so much more going on with
sharks beyond just their their gnashing teeth and uh and uh,
you know they're they're they're chopping at cages with divers
in them. And that's what we hope to really ultimately
reflecting this in this episode today. So before we before

(05:16):
we get into the interview with Mara Uh, we thought
we would just give a little bit of set up here.
So for starters, what are sharks? Well, this is one
of those areas where you see them in films and
on TV and if you think you know, but but
when you actually start breaking it down, it's it's really fascinating.
So sharks date back to the to the Ortivisitian period

(05:37):
four hundred and fifty four twenty million years ago. This
was before land vertebrates existed and before many plants had
colonized the continents. So sharks are older than dinosaurs when
in the grander scheme of sharks, now modern sharks, sharks,
as we know that these only go back around one
hundred million years. Yeah, but they are so they are

(05:58):
they are established players and in the sea. Yeah. And
of course one of the other if you if you
know very little about sharks, one thing you probably know
for sure is that they don't have hard bones. They
have cartilage, right, the members of the class condrict these
and this includes other cartilage based fishes as well, raised, etcetera.

(06:20):
And as we talk tomorrow, she's gonna end up referencing
some of these shark ken as well. Yeah, they're related.
It keeps coming up in our notes as well. So
speaking of Mara, who's Mara? Oh yeah, well Mara heart.
She is a coral reef ecologist by training, and she's
currently a research co director for Future of Fish flip Labs.

(06:41):
So Mara assists entrepreneurs and innovators with finding solutions to
the global over fishing crisis and her past work includes ecological, historical,
and social science research on a range of topics, uh,
you know, from fisheries to climate change impacts on ocean
life and she's the author of this wonderful book that
we've talked about on the show before. Sex and the

(07:02):
Sea are intimate connection with sex, changing fish, romantic lobsters,
kinky squid, and other salty erotica of the deep. Yeah.
In fact, Mara has been a guest with us twice
before this. She is so much fun to talk to
because she's so passionate about this stuff and really down
to earth about it at the same time. So I

(07:22):
feel like she's just so great at communicating marine biology.
We've talked to her about let's see osadas worms and
then coral reefs last year, and so we figured, hey,
shark weeks coming up. This is the time of year
when people are thinking about sharks. But why don't we
spend this in a different light, Because while yes, they're

(07:42):
scary and we have developed this entire like fear culture
around them, they are incredibly weird when it comes down
to how they mate and how they reproduce baby sharks.
So all right, let's just start off with some facts
about shark reproduction. Sexually, in sharks, they begin with the
production of sperm and eggs. But here's the thing, they

(08:05):
don't always coincide so determining when a female can get
pregnant gets tricky, and we talk about this in the
interview with Mara. Especially because they have that internal fertilization system,
the females can actually save sperm from sexual encounter with
a male shark, and that produces a limited number of

(08:27):
offspring per cycle. Now, while some small sharks will lay
eggs on the ocean floor, large sharks will give birth.
So I want to give some clarity between three different
kinds of sexual reproduction with sharks. The first is called oviparity,
and this is when sharks lay eggs on an ocean
floor and these eggs are encased in a leathery egg

(08:49):
case that's called a mermaid's purse. That's a very nice
little name for for for what I imagine is like
an alien egg. That's what and picturing in my head
is like face hugger egg. It takes between six to
nine months for them to hatch, and they have features
like tendrils, horns, and sticky mucous filaments. So these are

(09:12):
not pretty eggs. Oh, I've seen them. They have their
own a charm. Yeah. Well, the reason why they have
all these things is they helped the eggs stick to
the seabed. It's not just like a fashion statement. It's
part of adhering to the ocean floor. So the second
kind is ova viviparity, and this is when sharks carry

(09:33):
the eggs in their body, so instead of actually having
you know, laying the eggs and having the mermaids purse
come out, they are in thin membrane coverings inside the
mother's shark. Now, in some species, baby sharks will stay
inside the mother even after they hatch, and they will

(09:53):
swim around inside the mother eating unfertilized eggs. We talk
about this at length with Mara with regard to u
sand tiger sharks in particular. But this practice actually has
a name, and this is sharks get the best names
for things. Oh faiji, that's the that's the name for

(10:13):
when these baby sharks hatch and eat their unfertilized eggs
surrounding them. Then you've got the third kind, which is viviparity,
and this is when a shark gives a live birth
with no eggs. It's very similar to mammalion reproduction, except
the fact that the pups, which is what you refer
to baby sharks as, are immediately independent, and they've got

(10:36):
to fend for themselves after birth. So there's no like, uh,
like a training session where like the pups hang around
with the mother for a long time afterwards and learn
the ways of the ocean. They're just on their own right.
And we'll discuss this at length with Mara in the interview.
And another thing we talked tomorrow about is sharks a

(10:58):
sexual reproduction. So this is something we've just been learning
about in the last couple of years. There are a
few types of sharks that are known to be able
to reproduce without having a male fertilize their eggs, and
the process is known as parthenogenesis. Uh. The kinds of
sharks that we know about right now that can do this,
or the bonnet head, which is a type of hammer head,

(11:18):
the black tip and zebra sharks. Now, the first one
of these was recorded in captivity in two thousand one
in Nebraska, of all places, Nebraska's aquarium. The baby shark
the pup was actually killed by another fish shortly after birth.
But at first this was thought to be another case
of the sharks storing sperm so they could fertilize their

(11:40):
eggs later, but testing reveals that some of these cases,
actually the DNA is only the mothers, so it indicates
that there's a sexual reproduction going on. And we talked
tomorrow at length about this and the you know, kind
of the positives and negatives for female sharks on this
Other vertic bit species that can do this include turkeys,

(12:03):
komodo dragons, snakes and rays and in fact, eagle rays
and Boa constrictors are the only other species that have
done this in captivity. So the process itself is something
that we'll talk about with Mara. It's it's fairly uncommon
in a species when they've already had sex though, and sharks,
the other thing that's kind of interesting about their sexual

(12:25):
and asexual reproduction is that they can switch back and forth.
So this is kind of a last resort tactic when
they can't find another mate. It's not something that they're
doing all the time now. Fun fact, and Mara briefly
mentions this, but let's try to describe it here so
that you have a better idea going into this interview.

(12:46):
Male sharks actually have two they're not penises, but let's
call them penises and quotes. They're called claspers and these
are grooved organs that deposit their sperm and envelop along
the inner margin of each of their pelvic fins. And
Mara clarified for us off air, these are not separate organs.

(13:08):
They are part of the fin itself. But they only
use one of these at a time for sex. And
an inserted claspers tip will unfold and anchor in a
female and it uses these spike like clasper spurs to
do so it just sounds generally kind of awful. Yeah. There,

(13:29):
there's definitely a violent, violent nature to shark reproduction, and
that's that's one of the things that we'll talk about
with with Mara at length. Um like and and actually
how it ends up playing into reproductive strategies for for
the shark species. Yeah, absolutely, So. Okay, so we've got
sexual reproduction, whether it's laying eggs on the floor, carrying

(13:51):
the eggs in their body, or giving life birth. Then
you've also got this a sexual reproduction. You've got these
males swimming around with two penises that have barbs on um.
How could it get any weirder? Well, it turns out
that the sand tiger shark actually has cannibalistic babies inside
of it and we will talk with Mara at length
about this. I I like to refer to these as

(14:13):
a in honor of Chud, one of our favorite movies. Here,
it's stuff to blow your mind. I'm gonna call these
sudd cannibalistic shark underwater dwellers. Well, in the same tradition
of Chud, where you have the you have it stand
for different things. Yeah, I would say you could also
have a stand for cannibalistic shark utero dwells. Perfect. Yeah,

(14:34):
that's perfect. Why we're gonna go into this at length
with Mara, but we're gonna give you a little bit
of a primer that brace yourselves. This one. This is rough.
So in this species of shark, there's actually only eight
to ten embryos, but only one will survive birth, and
this is per uterus in these sharks. Because these sharks
have two utero they have a right one and a

(14:55):
left one, and the way that they survive is by
eating all of their born brothers and sisters. Uh. And
this is a whole process called adele phopheji that we're
going to talk about at length with Mara. But basically,
the idea here is that he's the first baby that's born, Uh,
breaks out, swims around and eats in a quote kill now,

(15:19):
consume later fashion. Uh, they basically kill all their siblings
and then for weeks afterwards devour their siblings inside their
mother so that they're born really big. They're born at
like three ft long. All right, Well, we're gonna take
a quick break and when we come back, we're gonna
jump right into the interview with Sex and the Sea

(15:39):
author Mara J. Hart. Well, Well, first of all, thanks
for taking time out of your day to chat with
us again to come back on the program and discuss
uh some marine biology. First, we just, I guess want
to know how's your summer going. What are you working on.
My summer is going well, and I am I'm working

(16:03):
on a whole bunch of stuff so um for a
future of fish where I work full time. I'm digging in.
We're trying to make seafood supply chains more traceable. So
that's very exciting and has to do with a lot
of trying to curb someone with the issues we have
in the seafood world. And then on the Sex and
the seaside, I'm working right now, I'm actually trying to

(16:25):
figure out how our current administration's new tactics are are
going to be affecting sex in the sea. So for example, um,
President Trump just opened the Atlantic toil or wants to
open it to um offshore drilling again, and um they
use these massive foundaries to do that. And there's some

(16:47):
big concerns about how how those exploration activities affect marine
life and sound in particular, can be really disruptive for sex.
So yeah, trying to work my way through, um, trying
to explain what some of those those impacts maybe so
that we can maybe ward off some of the worst
of them. Wow, I hadn't even considered that. Yeah, so

(17:09):
are you working like on an article or something along
those great, let us know when it's published. Thank you,
I will. It's uh, yeah, it's it's fascinating because and
it's a really interesting situation because you have it's not
you know, it's not down the normal political line, because
you actually have a lot of industry, the commercial fisheries,

(17:30):
the tourism industry. So a lot of the businesses are saying, hey,
wait a minute, when you go out and do this,
it like scatters the fish for weeks or disrupts certain
spawning habitat and spawning events so they don't come back
and you miss a season and that can really mess
up things for the future. So it's a very very
interesting um dynamic, and I'm trying to figure out exactly

(17:52):
what we can maybe be doing about it. And yeah,
just kind of raised the alarm for a terrible sound pun.
I guess back my summer and chasing kids around and
trying to make sure they have some screen on well.
Speaking of sort of taglines and slogans and all. One
of the sort of slogans we were kicking around for

(18:14):
this episode. This is Christians creation, so I can't take
credit for it, but we're thinking sharks life machines, not
death machines. Yeah, because because it seems like just as
much as people obsess over the you know, sharks, as
these killing machines, especially around this time of year was
Shark Week, that when you do the research and you

(18:36):
look at their reproductive system, it's like, no matter what,
these things are going to make babies. So yes, in
the sense that they're extremely diverse in how they do
it across across the animals known as sharks um and
especially then if you throw in rays, the diversity of
reproduction is amazing, But some species and some of their

(18:59):
strategies are really really vulnerable to disruption. So they'll make
babies for sure, but they don't make a lot of them.
They're like fish, And that's the big thing that I
think a lot of people miss um. And it's understandable.
You think a shark is like a fish, but they're
actually they separated, you know, almost half a billion years ago,

(19:21):
so it's um. They've been on a very different path
and there in their reproduction reflects that, and it can't
it can't handle it can't handle the same kind of
level of pressure from fishing, and they're really susceptible to
other other impacts too. So yes, though I like the
title in the sense that it reflects that they really

(19:43):
are an extremely diverse group. When it comes to reproduction.
You can find everything from egg laying all the way
through live births and tons of really weird stuff in between.
So I wonder if a lot of the branding that
sharks get, especially you know, especially the great whites and
and some of these more cinematic sharks we brand them

(20:05):
is so ferocious that we we just lose sight of
the fact that that their their place in the ecosystem
could be so ultimately fragile. Absolutely, and nature is a
dynamic balance, right, So there's always things that are trying
to grow more and increase their population and increase their offspring,
and then there are factors that come in and make

(20:27):
sure that no species overtakes everything, right, It's it's that's
what an ecosystem is. It's all of these opposing forces
of prey and predator, um of reproduction and death that
keep everything kind of at a level that's in in
some sort of balance. And that doesn't mean it's um frozen.
It just means that it's balanced. But if you take

(20:48):
all of that predatory pressure away, if you did remove
these big predators, which is what in the ocean we
tend to do um, which is opposite right to on land.
In the ocean we eat all the big stuff to
tune out the sharks group or snapper. These are all
predatory species cod they're all the top predators. You remove
that and then there's nothing to keep in check the

(21:11):
growth of these smaller types of species that are meant
to grow fast and reproduce fast so that they can
deal with that predation. And so then they kind of
spin out of control that throws the whole system out
of balance. So sharks are really really important, um, in
terms of keeping an ecosystem in the ocean healthy, and
we've hit them pretty hard. I think the numbers about

(21:33):
a hundred million sharks are taken out of the water
that we know of by commercial fisheries each year, and
then of course there's a lot of illegal fishing for
sharks as well. So yeah, they're really important and they're
really cool. Again, there are really ancient, very distinct lineage there.
They they're they're just rad in terms of the stuff

(21:55):
that they do, um, and it's we don't see it
anywhere else. Uh So for just simple diversity sake and
fascination sake. Uh, they're amazing. Yeah. I think from our perspective,
like doing the research leading up to this, all the
variety of ways that they reproduce are so unique and odd.

(22:16):
It's just shocking to me that that's not the stuff
that is in the headlines, you know, or that like
I featured in Shark Week versus all the other you
shouldn't be shark sex week, Yeah exactly, Yeah, it would
be so rad um. Yeah, and it goes on and on,
and there's still so much we're figuring out. But they

(22:38):
really yeah, they really really do. And some stuff is
so similar to mammals it really starts to kind of
um mirror what we think of in our own kind
of group of animals. And then they do stuff, you know,
way on the other end that's more like chicken and fish,
you know, laying eggs and having a totally different strategy
there so and everything yeah, in between, and then off

(23:02):
on tangents that we don't see on land, well in particular,
I think you're referring to to live birth. They're correct, Yeah,
I mean little baby sharks are born with belly buttons.
It's like we are, which is really cool. Uh. They're
called umbilical scars, and they do actually heal up and
go away. So it's slightly different in in many species
especially it's it's in the larger sharks are the ones

(23:24):
actually people tend to be more familiar with. The mothers
give birth to a lot young uh, and they have
an umbilical cord. It's attached to a placenta. The way
the placenta works and sharks is different. It's not attached
to the female and connected to the female in the
same way, but it is a very energy intense process

(23:47):
for the female to deliver these these young and um
they're born when at a time live from the mother
and they sort of unlike mammals that are born fully
fun tional and ready to swim off, so there's no
maternal care. Um. In fact, they sort of come out
of her and will swim very rapidly to break free

(24:09):
of their embolical cord and then they slim off and
that's it. But the process of pregnancy she is carrying
inside her, yeah, developing embryos and live fetuses, and then
they take off. So it's it's pretty neat and they're
they're really cute and they're born. I love baby baby.

(24:30):
Sharks are adorable. They really are. Uh, this is this
reminds me. Uh. Joe and I reached the recently recorded
an episode where we talked about various sort of fossil
action scenes, and thesaurs came up some of the live
births that are attributed to them, and I was I
was really struck, and I'm struck now thinking about the

(24:50):
sharks as well, that you have all these different forms
of large predatory aquatic creatures and they all sort of
evolve into sort of similar forms, you know that they
and and and end up depending on live births. That's
really interesting. I hadn't thought about that, but it's true.
And I know there's one or two amazing fossils that
show in the ideas store like that. Isn't there like

(25:14):
one where you can see the baby inside. I've seen
that somewhere. Yeah, so yeah, it is amazing and I
think you know, part of the strategy there is that
it is very resource intense for the female, but once
those puffs are born, their likelihood of survival is very

(25:35):
very high, So they sort of are getting them through
that um, that early stage of um sort of mass
mortality that that fish larvae occur. You know, fish are
putting out millions and millions and a very very small
percentage of those eggs will ever be fertilized and then
a very very small percentage will ever grow to become

(25:57):
an adult, whereas in sharks. Yeah, it's it's a different approach.
It's put a little bit more time and energy into
into rearing inside the young, but it also has to
do with this internal fertilization, right, So it's this funamount
difference between being able to brood your young internally in
the female body be able to fertilize the eggs inside

(26:20):
the female, which again has some advantages in the sense
of making sure that there's less space, um less diffusion,
and so it could just be a result of that.
Is one of the ways that internal fertilization works well
is that you have the potential to real live young.
But again instructs you see also internal fertilization leading to

(26:41):
egg lane or this in between, where the females will
have eggs, but the eggs are kept inside the female
for quite a long time, so that by the time
she lays the eggs there's only a couple of days
before they hatch. So again you have all of these
different kind of gradations and in turn of how they
do it. But it is neat that you're write that, um.

(27:03):
We see this in other large predators in the ocean too,
in terms of a live birth. This reminds me actually,
and I haven't told Robert this yet. One of our
colleagues here, Holly Fry, who hosts our history show, I
was talking to her about this the other day. She
used to be a volunteer at our local aquarium, and
she was saying that that's how she learned about the
internal fertilization process, is that she was working with one

(27:25):
of the sharks there and it spontaneously started giving birth.
And she was like completely surprised, and the marine biologists
there at the aquarium we're like, no, this is cool,
it's okay, Like this is a thing that happens with sharks. Yeah, yep, yep,
and and it is. It's it's amazing because it's not
what again, especially if you think of sharks as fish,

(27:46):
or a lot of aquarium that do have sharks, like
zeber sharks and things that do lay eggs. Often you'll
see a display that shows eggs at the different stages
and they'll be backlet I don't know if you guys
have ever seen that, but some of the aquari Virginia
fut Aquarium has this and and some others where you
can kind of see the developing shark in the egg case.

(28:08):
So a lot of people associate sharks again with fish
with egg laying. And the Trucia has many many of
the big ones, from great whites to lemon sharks to
read sharks. They all hammer heads, all live birth so
we've got to talk about and and help me out
here if I'm pronouncing this wrong. For so, it's san
tiger sharks in particular, uh adele faux feji, that's right, Okay,

(28:34):
So literally means eating your brother, Yeah, embryo cannibalism. And
so my first question is one of my favorite things
about your book is how you have the little fictional
vignettes set up within the book. And I want to
know why there wasn't a Delpho Fegi vignette and there
really that would have be like the best horror movie ever. Well,

(28:59):
you know, and it was so because there was a
couple of these where I was, you know, I did
start to write several vignettes that did not make it
into the book because I just got to the point
where I was like, I don't think people actually want
to know level because it is it is gruesome, I
mean it really, So there were certain strategies that I said,

(29:23):
what we'll just leave it to the imagination and I
don't think I have to paint um much more of
a visual on this one. Well, instead of instead of
doing that, can you walk our audience through why this
occurs and how it benefits the mother and the offspring
absolutely so. And this is you know, it's still a theory,

(29:43):
but there's been some work, i say, over the last
two to three years, much of it led by Dr
Damien Chapman. And the thing that you have to understand
is shark sex. Again, it's internal, right, internal fertilization, and
it's pretty rough. In fact, most female sharks have thicker
skin so they can deal with the fact that the

(30:05):
males bite down on them to hold them in place
and roll them into place. So it's not a pleasant
experience for the female. Um. She probably and again we
can't really know, but in general, for what we see,
the limited amount of shark sex that we've actually been
able to view in the wild, she doesn't seem to
really um, she would like to limit those encounters, right,

(30:27):
um shark. The male clasper, the male sex organ also
often is barbed and hooked. We got notes about that
in here. Yeah. So again for the female, like having
multiple multiple matings is not awesome. It does bring a
true risk of um being wounded, being injured, and also
later infection from open cuts and things. So that's important

(30:51):
to know because it basically means the female is incentivized
to do whatever she can to limit how much mating
she has to do. So with that as a context,
what happens in the San Tiger shark is amazing. So
sharks have um to terize right in the left, you
can think of it that way. And for San tigers,

(31:14):
they give birth to only two pups at a time
each season, and it's one from each you to I.
And these pups are huge, they're about three ft long,
and I think the females, you know, you might have
a nine or tenth fi female. So this is you know,
giving birth to a baby that is a third the
length of your body. That's that's a big offspring. Just

(31:37):
the whole thing sounds awful for these poor lady sharks.
So that's a you know, that's a big deal. Um. However, again,
that means you have an offspring that is unlike, there's
not a lot of stuff in the ocean that's going
to eat a three ft long fish shark. That's a
pretty hardy, sturdy offspring that can probably send for itself

(31:58):
pretty well. Okay, So to get an offspring that big,
there's not a lot of room and you need a
lot of nutrients. Okay, so you have females who likely
um will benefit from not having to have multiple encounters
with males. They want to limit that amount of sex,
but at the same time they want to make sure

(32:18):
that you know that they're having a male um who's
who's rather fit UM. So what happened was what seems
to happen is and this is what Dr Chapman discovered
kind of recently. He was able to look at um
pregnant females that have been caught in some sharp protection

(32:40):
that's off the beaches of South Africa, and so he
had access to the pregnant mothers and the developing embryos,
and he ran some some tests, paternity tests in particular,
to say how many how many males are these females
actually meeting with, And it turns out that they were

(33:00):
mating with several males. So within each uterus there were
multiple embryos that had each been fathered by different sharks,
by different males. However, there was always one one of
the embryos was over always substantially larger than the others.
And it seems that whoever this female mates with first,

(33:24):
that guy, that male is fertilizing two eggs, one in
each uterus, and those eggs are dropped it seems a
little earlier. And so these embryos, one in each, the
right and the left us right, they get um they
get a little bit of an advantage, and they're growing
a little bit ahead of the next suite of eggs

(33:45):
that seemed to come along. And what this means is,
and this is basically where it gets a little bit funky,
is that if that female mates with with a male,
she gets pregnant again, one each on each side. Then
if she is approached by other males, she can make
with them again without really having to struggle or try

(34:06):
to avoid that meeting. So she can kind of, um
perhaps allow that meeting to happen in a way that
maybe doesn't harm her as much. And those males then
are fertilizing the next batch of eggs. But the next
batch of eggs and the embryos that come of it
never make it because the bigger embryos, the first guys,

(34:27):
they actually hatch out of their little facts inside the
uterus and eat their siblings as they're developing, so it's
all of their help brothers or sisters. So what what
Dr Chapman found was that when he did these fraternity tests,
not only did he find that there were multiple males
for these different embryos, but more than half of the

(34:48):
time the two biggest embryos, one to each uterus, were
from the same father, so those were full siblings. So
it means that the male it gets to the female first,
we think, has a better than average kind of chance
of probably fertilizing that first batch of eggs, and those

(35:09):
embryos are getting a growth advantage. The other way it
may be working is that if it turns out that
the male that's meeting with the female or meeting other
males meeting soon after, whosever fitter. Maybe their embryos are
growing the fastest. But either way, the two largest embryos
on either side, so only one of the males, only

(35:31):
one male's offspring ever make it out into nature, and
so it's it's kind of it's a I know, it
gets a little bit heavy, but basically what you can
think is for the female, the strategy means that she
doesn't actually have to worry about who she meets with next,
because she's only going to give birth to that first

(35:51):
male's offspring, and the rest are basically just fertilizing food
for her developing embryos. So she's choosing with the first
one and then the everybody first. Yeah, and then she
doesn't have to waste energy, because it's very it can
be a lot of energy to either try to continually
swim away from advancing males or to struggle against advancing males. UM.

(36:14):
So what this does is it means that she can
sort of be picky at first, but then after that
she doesn't really have to worry too much about the
fact that maybe these males aren't the most fit or
are going to you know, be approaching her. She can
kind of mate with them, maybe acquiesce a little, and
their offspring, their genes are not actually going to get

(36:37):
out there and kind of mess up her offspring. Um.
So it's this very and we don't Again, this is
very early stages. But what's very intriguing is if it
was just random, meaning if she was just mating with
whoever whenever, you would wouldn't see that the same male
would constantly be bothering both of the biggest embryos. There

(37:02):
would be a little bit more mixing up of of
who's who's offspring wound up, making it out into the world.
So the fact that it's the full siblings from that
likely that first mating that got the growth advantage that
then eat all the others, mean that there there could
be an advantage there that the female taking UM taking
on to say, Okay, I'll meet with the first guy,

(37:22):
be picky with him, and then after that, I don't
really have to worry about it because these guys are
just basically going to fertilize eggs that that get eaten
by my developing young So yeah, it's pretty gnarly. And
there's some pretty cool videos they've done UM with fiber
optics where you can go and if you google santiger,
shark cannibalism and you'll see like in the womb these guys,

(37:45):
I mean it is they look like demon aliens. They
have huge eyes, these um very well formed beef and
they they crack out of their little egg case and
they go and they'll puncture the egg cases of all
the other embryos. And they won't necessarily eat them right away, right,
they kill them first, right, and then they eat them

(38:05):
over the course of weeks. Yeah, so that they can't
so that they can't grow and compete, So they kill
them given all the violence we've discussed in the shark mating.
I mean, it makes one think, wouldn't wouldn't it be
great if if the females could just reproduce without the
males being involved at all. Which, yeah, which leads to

(38:25):
the next question. Uh, I was really amazed to read
about this in your book. Either either I was not
aware of this or I'd forgotten it, But you talk
about how sharks are capable of parthenogenesis, sometimes referred to
as virgin birth. So what do we know about that
in sharks and why is it? Why is it difficult
to study in the wild. This is one of my
favorite active areas of research. So over the past I say,

(38:51):
maybe five eight years, we've all of a sudden um
and this is a lot to do with genetic tools
that are able to show us these this kind of
information based on Vienna samples. But we've found that at
first it was we saw it an aquaria where a
female that had been separated from a male for years

(39:13):
and years and years all of a sudden to give birth.
And we know that females can store sperm for a
really long time, like three years, four years, So at
first it was assumed that this was a sperm storage thing.
In in many cases it is, but we also started
to discover through again better genetics, that that's not always

(39:37):
the case. Sometimes they're doing virgin birth, and what version
birth is is it's where the female the egg undergoes
this really unique process where the egg itself kind of
splits and then refuses with its split part and conform
a viable offspring. So there's reshuffling of DNA, which is

(40:00):
what happens with regular sex normally between a egg and
a sperm, but this time it's between an egg and
kind of another part of the egg. And what it
means is that you have a genetically unique offspring. It's
not the same DNA code is a mother. It's not
a clone. It's not it is not a clone, right,

(40:23):
So this is really important because it's not it's it's
different than other kinds of a sexual non nonpaired reproduction,
which is cloning, where you get a genetically identical individual.
In this case, there is this reshuffling. You're just reshuffling
within the mother's DNA options. So it's genetically unique the offspring.

(40:48):
But there's two things that are really important to note
that that happened in this process. One is that even
though it's genetic reshuffling, it's still a less diverse amount
of UM sort of new new genetic blueprint then you
would get if you had mixed a sperm in and
egg like two individuals. Because you have you just have

(41:09):
a smaller you know, set of genes to to mix up,
because it's just the one mother's DNA that gets three
shuffled there than a mother and a father. So it
is less diversity in terms of over time. If these
offspring were produced, they're they're not as diverse genetically as
UM they would be if they were through regular um

(41:30):
full sexual reproduction. The second thing is you can only
have one sex because it's coming from the mother. The
sex chromosome that she has is in this case, like
with sharks, it's like the equivalent of you can think
of two xs, so that she only has those two.
It's the same the same two sex chromosomes. So no

(41:52):
matter how much you read shuffle, you're only going to
get excess. So you only get females in sharks. So
when this prod has happened, if you imagine it were
to happen forever, like if all female sharks said screw this,
we can do partenagenesis. We don't we don't want males anymore.
Over time that species genetics um diversity would decline and

(42:15):
your sex ratio would get so skewed that eventually it
would be a big trouble. So it's an awesome, fascinating
strategy that allowed a female to reproduce, and likely it's
used when um, she can't find a mate easily. It
does in sharks, the ones that we know can do this.

(42:38):
It's it's um called facultative parthena genesis, and that means
that it's by choice. She can also reproduce sexually, and
we know that they do do that most of the time,
so it seems to be a technique that she sort
of calls on perhaps when it's been really tough to
find a mate. And part of what supports this is

(42:59):
where we've seen it in the wild is in these
endangered small tooth sawfish where their populations have crashed over time,
and we see that this this level of parthenogenesis is
is very apparent when they've been doing these genetic sampling
and it's just the first time we've seen it in
the wild. Part of the reason why it's so tricky
is you have to be able to sample the pups

(43:22):
and they like to be able to. Scientists also like
to be able to sample the same mother to really
see like is this the mother's DNA that's getting getting reshuffled. Um.
I think the technique is getting better and better now
so that they could go out and test for this
just justin young sharks and see um uh if it's
if it's present. They're able now to kind of filter

(43:42):
to see is their male DNA there. There are certain
screens they can use, but um, it's it's been very
difficult to do that in the past. Um. So this
is again a new tool that they're they're just starting
to develop. And um where where they have tested it
and seen it a positive result has been in this
very highly endangered species or again in aquaria where the

(44:04):
females have no access to males um for a long time.
So yeah, it's it's really cool. It's basically the female
being like, well can find a male, might as well
go for it myself. And it seems to be in
very diverse. It's only a handful of species that we know,
but they're very diverse species. So it doesn't seem to

(44:26):
be just in one group of sharks. Um so that
kind of makes us really curious regarding, um, yeah, how
prevalent it could be and how often it's called upon.
All right, we're gonna take another quick break and when
we come back, more shark talk. So, uh we we
are putting this to the podcast episode out around the

(44:48):
same time as Shark Week, So we we thought we'd
ask you a few questions about Shark Week. Uh So,
first of all, did did you grow up with Shark
Week like like we did, where it's just kind of
this because my at least memories are just it's it's
all during the summer and it's just all these shark programs,
and so what do you do? You just watch a
bunch of shark programs? Absolutely, I mean I was, Yes,

(45:10):
I was hooked. And actually I have to I have
my my one, my fifteen seconds of fame that we
all get, right, was in the late nineties, I was
on Shark Week. I had a little clip where I
got to I was I was taking a little baby
lemon shark out of a net down at the Shark
Lab in Diamoni, Bahamas with the legendary Doc Gruber. So

(45:33):
it was near and dear to my heart because it
was the show that, actually, you know, this whole week
dedicated to trying to show the science and amazing natural
history of these incredible animals. So I was, Yeah, I
was a huge fan um again back in in the nineties,
and it's interesting to see what's happened since. Yeah, I mean,

(45:57):
it's our understanding that this year, apparently a shark is
going to race Michael Phelps on shark Ate this year.
I don't know how they're going to pull that off.
I've been hearing these rumors too, and I am it's
it's really interesting to me because selps is fast for

(46:19):
a human, right, But I don't know. I mean, have
you ever swum with a even like a butterfly fish?
They're really fast. Yeah. I was recently at the at
the beach with my son and we kept he kept
telling me, oh, can you You've got to catch one
of these fish that's in the surf, and we had
this little hokey net, you know, and they're just those

(46:40):
little fish are so fast, so swift, there's just no
catching them. So I can imagine that Phelps is just
completely boned. If he's going to raise a great white shark, yeah,
I would. My money wouldn't be on Phelps for for
several reasons. But I am curious about like how how
they're going because also like sharks, like they don't swim

(47:01):
in straight lines. Where where is this? How? How? And why? Again?
What is it? Just to show how a simulation would
be cool? I mean, I'd love to see a really
neat animation of like, here's the fastest person, Michael Phelps.
He could go this fast. A great white would do
that in you know, at tenth the time. But yeah,
it'll be interesting because I can't find exactly what it's

(47:23):
all about. It's just that they've just been like feeding
this rumor of Phelps versus great white and uh, I
kind of can't think of any anything except actually walking
on land where Phelps maybe a great white? Oh that
would that would be such a cruel twist, wouldn't it.
If it turns out the races on land, it actually

(47:43):
turns out that the way Michael Phelps reproduces is by
having babies eat is the eggs inside of him? That
would be that would be very interesting, Or maybe it's
an imposable song unscrewing a jar lid, he'd probably win.
But yeah, it's it's gonna be interesting to see. And again,
if they're doing it as a way to kind of

(48:07):
bring home an analogy of like how fast sharks are,
then that's great, um, because people have seen self and
he's the fastest. I mean, he really is one of
the he's incredible for our species. What he can do
in the water is amazing. And comparing that and showing
how that is not even close to what a shark
to do that that could be a really great way

(48:28):
to help people appreciate just how how fast these animals
are and how perfectly designed they are for their environment.
I mean, evolution has had hundreds of millions of years
to fine tune the body shape of sharks, and if
you look at their shape, it has not changed that
much in that that time. There's many different you know,

(48:49):
body shapes for sharks, but that general form for the
ones that are free swimmers you know, in the water column,
not the ground sharks. They all have very similar things.
And the Navy uses it to make their missiles go faster,
and you know, we we can certainly see, um, how
evolution has maximized that incredible predatory speed oriented sleekness. We don't.

(49:15):
We don't have it even when you're wearing those really
tight bating suits. As far as Shark Week goes, and
I guess, not just Shark Week, but just sort of
our cultures associations with sharks, our relationship with sharks, it
seems seems like it's it's it's ultimately like a little
bit challenging from a science communication standpoint because on one level,

(49:36):
like everybody is still like a six year old kid
inside with sharks to a certain extent, there's something about
the ferocious shark that is appealing, is is endlessly fascinating
that it's it's a little bit scary, uh, And generally,
you know, fun scary if you're not in the water,
I guess. But then you do want to communicate these
these more important issues, like, you know, what's going on

(49:57):
besides biting a cage with the the human in it,
beyond you know feeding, uh, you know, chum to to
a shark and just watching its its teeth snap. And
you want to relate these important issues of conservation uh
to the general public. But but how do you I mean,
how do you end up weighing those two things, how
do you how do you how do you proportion the

(50:19):
informational meal. I imagine it's one way to put it.
It's a great question, and I think as a community,
whether it's the science communication community or the shark science community,
we're still trying to figure it out. The key is
that it's what you said at the beginning, right where
all those excited six year olds inside, where there is

(50:40):
a fascination, even if that fascination is strongly rooted in fear,
it's a great way to get people engaged. I mean,
there is a shark Week because people want to learn
about these animals. And I think where I get so
frustrated with discovery and especially was appalled. I would say
the last you know, five years or so, they really

(51:03):
I think took a turn for the worst, though I
do think they are trying to correct. Last year I
think was a little bit better. But there's no need
to play off the fear. The fear is there, the
fascination is there. People will show up and they want
to watch. So take it to the next step and
use that as the doorway that opens up to this

(51:24):
world of unbelievable natural history. Whether you're talking about their reproduction,
whether you're talking about their sensory systems, whether you're talking
about their ancient lineage and evolution in a water environment,
and all the things that they do that's different than fish.
There's so much whether you're talking about their role as

(51:45):
apex predators in controlling an ecosystem. There there is so
much that is rooted in science and that we are
learning all the time. We don't need to make up
and exaggerate it. There's no there's just absolutely no no
need for fabrication. And that's why I was I think

(52:08):
what has been so bewildering about the fact that they
sort of sharkly took this sort of strange route towards
exaggeration and too really hyperbole to the point of misrepresentation.
It's not necessary because you're not you don't have to
attract people to watch this stuff. You really don't. People

(52:30):
aren't genuinely curious. And what we are learning is unbelievable.
I mean, the fact that you have some rays that
produce a milk like substance that they're developing embryos are
nursing off of in the womb. That's fascinating. That's amazing.

(52:51):
Nobody knows that. We're still trying to figure out how
they do it. What does that mean? Do you call
it milk? It's not in a mammal. You could have
so many cool conversations about this stuff. I mean, one
of the articles I I sort of um wrote after
the books I couldn't dig into it enough is this
amazing work by a guy named Dr Jim Gelschlider. And

(53:13):
he he's trying to figure out like paternity tests work
in sharks, but pregnancy tests don't. We cannot figure out
how to make a pregnancy test for a shark. And
it's because their their hormones and their biological systems chemicals
are so different. They regulate their physiology so differently. We've

(53:36):
done it for fish, we've done it for mammals. We
cannot figure out how to do it for sharks. And
it seems like paternity tests work, pregnancy tests don't. That's
fascinating and it opens up a whole way of discussing
not only why that is, but why that matters. If
we can't figure out when these sharks are pregnant, how
long they're pregnant for, how often they're getting pregnant it's

(53:58):
really hard to know what is appropriate management. How much
can we fish? You can't answer that question. You can't
know how many sharks to take out of the water
if you don't know how many sharks there reproducing to
fill that gap each year. So these are fundamental questions
that deal with fascinating aspects of their natural history and biology.

(54:22):
So there's so much to dig into that I think
we can. We can use the fear, we can use
that fascination to say, yeah, these are crazy, crazy predators
and they are really really good at being predators. But one,
you're weird in the ocean, you know, like you're not
a burger. You know, imagine if if you eat you know,

(54:45):
burgers and salads and then somebody plunked down this thing
in front of you that you've never seen before. It
smells different, it's the textures different, it's got we're dressing
on it, like you're probably not going to just dive
in augusto. Most sharks think I think we're weird. I
have to say that lately when I have gone into
the ocean, and especially most recently, because I managed to

(55:07):
glimpse a shark of some kind, I wasn't able to
make out the species. But I think back to an
episode of The Simpsons, I believe, where there's a brief
clip of a shark jumping out of the water and
grabbing a gorilla out of a tree and then and
and it's just such an you know, an unbelievable and
ridiculous scene, and I think, well, that's basically what's happening here.
I am that gorilla, and that shark has not evolved

(55:29):
to to to eat me. It hasn't. And I mean
when you think of the numbers of times people are
in the water with sharks and nothing happens, I mean
more than half the time, we have no idea they're there.
I mean, that's the truth. And they're not interested, it really,
really aren't. When an accident occurs, it is tragic, of

(55:51):
course it is, and of course it's scary because we think,
oh my gosh, this could happen. But you know, the
statistics on it speak for themselves and most people's experiences,
even those of us who want to go and see
a shark, it's really hard to find them, and it's
getting harder to find them. I mean, sharks are in

(56:13):
big trouble. We we are over fishing them across the board.
There are a few species. So there are some small
species often like off the east coast they're known as
dog fish, that are smaller, they reproduce a little more
quickly likely can sustain a fishery. But the big sharks,
the hammer has, the reef sharks, the great whites, those

(56:36):
they can't take the level of fishing pressure, whether it's
targeted or accidental, that that we've been putting out there,
and they are they are getting creamed and their numbers
are plummeting um and it's it's really scary, and it's
really sad because it's it's it's not necessary. So that fear,

(56:58):
I think what I would to see is a way
to show that that fear should bring that healthy respect,
which is the same that we carry when you go
hiking in the woods and you think about being smart
about bears, right, do the things you can do to
minimize a chance that you're going to um invoke any
kind of an attack, but otherwise be decided if you're

(57:23):
lucky enough to actually see one, it's a pretty special thing.
So on the subject of of shark conservation, where are
we with short conservation, like what are what are where
where our victories and what are the where are failures?
And what are the challenges ahead? Yeah, so i'd say that,
you know, I think the last few years have have
been a bit of a turning point, but it's it's

(57:44):
a very early stage turning points. We've really got to
keep the momentum um. The biggest driver of sharks declines
has actually been the rise in Asia of especially China,
of sharks in soup as a delicacy. This is a
dish that is served at weddings at you know, very

(58:07):
fancy banquets, and it's a considered a sign of stature. Um.
So it's a way of showing off really, And there's
no nutritional value in the sharks fin at all. It's
just it's like eating your ear, right, It's just a
bunch of cartilage, doesn't doesn't have any nutritional value and

(58:27):
the method of harvest is extremely um destructive and gruesome.
So what the what sharks finning involves is literally spinning.
So they will catch a shark, cut off its fins
and then throw the body back over. That way they
don't have to worry about taking up storage room on
ice with the bodies. So there that sharks obviously die.

(58:51):
They can't, you know, they either bleed to death or
they drown because they can't swim without their fins. And
for many sharks that they can't swim, they can't get
enough oxygen and they and then I guess suffocate UM.
So it's really gruesome. It's really wasteful because if you're
gonna kill a shark, you might as well eat the meat,
right use the animal. And it doesn't feed people. It's

(59:14):
not like this is going to feeding populations that need protein.
So it's just wasteful across the board in a highly
unsustainable practice. However, it is very lucrative. These shark fins
step for very very high prices, so one of the
challenges we have is curbing that demand. There's some campaigns

(59:34):
out there that are really trying to educate UM the
consumer to say, don't have this at your weddings, don't
have this at your banquets. This is not not something
to encourage. There have been very strong and some very
successful campaigns to UM create policies that ban the sale
and trade of shark fins. So this is happening in

(59:54):
the States. There's several cities that have banned the import
or trade of shark fins. There's also some really great
advances in UM again in uh DNA testing. So one
of the hardest things is that once a fin is
cut off a shark, it can be really hard to
identify what shark that came from. Some of the most
threatened species have gotten protection under SIGHTS, which is the

(01:00:18):
Conservations for the International Trade of Endangered Species so c
i t e S. And if if it is found
that somebody has a shark fin from one of those species,
then they can be in really big trouble and they're
huge fines. So internationally there are tools that allow for prosecution,
but it's been hard to prove which species of sharks

(01:00:40):
fin has come from. Now we have some better genetic
tools that are allowing for this, and Dr Debra Abercrombie
is one of the leaves on this. She was working
for a while at a Stony Brook University UM and
and she and a group of scientists there have have
helped create some kits that allow UM Enforcement office or
to test so if they go and they see shark

(01:01:03):
fins in a restaurant or in a warehouse, they can
now go even if that fin has has really degraded.
They can now go and test that product to see
if it is from one of these banded species, and
they've had great success in being able to now prosecute
some of these illegal traders, so that's really positive. Um.

(01:01:24):
The other victories that we're seeing are shark fishing bands,
shark sanctuaries are now um really gaining traction. The first
was set by Palau, the first national shark sanctuary. They
banned all shark fishing in all their waters in two
thousand and nine. Other countries have since followed Micronesia, New Caledonia, French, Polynesia,

(01:01:47):
um at all in the Pacific. Then in the Caribbean
there's the Bahamas, the Cayman Islands, Honduras, um the Bridge
Virgin Islands, I believe. So there's probably dozen, maybe maybe
a little more, maybe fifteen countries or networks of countries
around the world that have started to ban shark fishing
outright and they're finding that and there's been one or

(01:02:11):
two studies, I know there was one in Palau that
looked at the economics of this and the value of
a shark when it's fished and killed and sold for
meat is far far less than the value of that
same shark on shark dive year after year after year.
So people who now know that these places have healthy

(01:02:32):
shark populations and want to go and see sharks, they
pay a lot for that. And so these countries are
actually realizing that if you if you want it in
economic terms, there is good evidence that it makes good
sense on a dollar value to keep your sharks alive.
It makes your ecosystem healthier. And they're now booming eco

(01:02:55):
tourism opportunities that can come with that, and oftentimes there's
um they to retrain fishers uh to be able to
take advantage of this kind of different livelihood. And again
most of the time these fishers are not fishing to
see themselves. That's not why they're fishing the sharks. It's uh.
It really can be a great way of seeing how

(01:03:16):
ego tourism can be driving better conservation and the economics
are are really on the side of protection when it
when it comes to those those big sanctuaries. And this
is the last thought related to that. Part of why
these large sharks fitting and also sharks fishing bands can
work is because we now have technology like satellites and

(01:03:37):
drones that help these small island nations monitor and regulate
these huge expanses of water that they never were able
to do before. You know, they there's no way Palau
can patrol for illegal fishing in its waters using boats.
They just can't to if they can't enforce that there's

(01:03:58):
I can't remember the number, but you know, land size,
the water is, the ratio is not in their favor.
But through things like Eyes on the Sea and Sky Truth,
these are programs where NGOs have partnered with governments and
foundations and UM the expertise of technology companies like Google
to use satellites and start mapping fishing activity UM and

(01:04:22):
drones to map fishing activities so that they can actually
have early detection and deploy and enforcement boat very strategically
when they know there's somebody in that area. And that
has really changed the game across the board for illegal
fishing UM. And it's really really exciting because these tools
are are are critical to our ability to turn what

(01:04:42):
used to just be on paper protections into actual protections.
So I think there's a lot of victories UM, but
still some very significant challenges. Yeah, from what you've told
us today, it sounds like sharks have a lot more
reason to have horror films about us than we of
horror films about them eating us. And that absolutely that

(01:05:04):
would be I would that's the horror movie I would
want to write. Um, Yeah, well, I'm I'm I'm actually hoping,
you know that the sensationalism of the sort of symbology
of sharks as killing machines starts going away soon. You know,
this Phelps thing that we were talking about earlier. At
least he's racing the shark. It's focused on the speed

(01:05:27):
and not on something else, you know, So I'm hoping
for that. I agree, and I think you know. The
one thing I can say is, especially with Shark Wheat,
for while your listeners out there right in and let
them know that you like the programs that aren't just
about the killing and the ferocious predator stuff. You like
the interesting stuff on the science and the natural history,

(01:05:48):
and you want to know more about how sharks do
what they do, not just how they act as predators,
because they're incredibly complex. And again, whether it's their sex
lives or the way that they sense their environment, I mean,
their their history over time, their cultural the myths and
culture around sharks. I mean, all of that is fascinating,

(01:06:11):
and I think the more we as as consumers of
this information can show that we we really like all
of it, and we really like it to be grounded
in real science and we don't need the sensationalism, the better.
And then, of course, as scientists, I know we're watching
and we need to continue to be really vigilant and
and hold hold these kind of programs and especially Shark

(01:06:34):
Week to a very very high box and make sure that,
um we're calling out what may be misrepresentation or hyper
beliefs so that we can continue to steer it back
to a direction that it truly is informative and accurate. Um.
So yeah, that would be my little soapbox speech. Let

(01:06:55):
them know you like the science. Well, Mar thanks again
for joining us here on the show. You I think
you and Mary Roach the only people we've had on
the show three times, so you're in a wow that
is like, that's hugely I'm super humbled by that. Thank you,
And I love talking with you guys, and I just

(01:07:16):
appreciate so much I've been obviously I'm a fan and
listen to your podcast and just love how diverse and
how deep you guys go on topics. It's it's a
really it's an awesome combination. So thank you for letting
me be a part of it. All right, So there
you have it, another fun, fascinating talk with mar j Hart.
Every time we have her on the show, she provides

(01:07:37):
this wonderful conversation, just a just an outpouring of marine
biology content. And if you want to look up those
past episodes of the podcast where we talked to her,
I'll be sure to link to those in the landing
page for this episode it's Stuff to Blow your Mind
dot Com. There'll also be a link out to places
where you can buy her book, Sex in the Sea.
One of the best things about having Mara on as

(01:07:59):
a guest too, is that Mara engages with us on
social media, So if you want to check out whatever
inevitable conversation we end up having with her, just see
what she has to say after the episode airs. Definitely
look out for that. You can find us on social
media on Facebook, Twitter, Instagram, and Tumbler. And don't forget
to check out Stuff to Blow your Mind dot com.

(01:08:21):
That's where Robert's going to post that stuff on the
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you want to get in touch with us directly, you
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this year, uh, give us some feedback. What do you
think about it? How do you how do you think

(01:08:41):
it lined up with some of the issues that we
were discussing in this episode. Let us know. You can
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(01:09:02):
Does it how stuff works dot com