Hi, you're listening to Cultivate
Curiosity, a.
Podcast that inspires the next generation
to stay curious.
Cultivate Curiosity is brought to you by
the Emerald Coast Science Center, a
nonprofit.
Interactive science museum and steam
educational facility in Fort Walton Beach,
Florida.
This podcast is perfect for anyone curious
about the world we live in, because.
You never know what we'll talk about
next.
Hi.
My name's Harley and I'm an educator
and the community affairs coordinator here
at the Emerald Coast Science Center.
Hi, my name is Diane and I'm
the director and hi, my name is.
Jacie and I'm the Social Media coordinator.
And today we're going to be talking
about Shark Week, which is this week.
It already started.
So we just want to talk a
little bit about sharks, what Shark Week
is, and some other things as well.
So the first thing we're going to
talk about is Shark Week, which is
an annual week long TV programming block
at the Discovery Channel, which features
shark based programming.
Shark Week originally premiered on July
17, 1988, that'd be 35 years ago.
It was originally devoted to conservation
efforts and correcting misconceptions
about sharks, but over time it grew
in popularity and became a hit on
the Discovery Channel.
Since 2010, it has been the longest
running cable television programming event
in history.
It has been hosted by many notable
people and last year in 2022, it
was hosted by Dwayne The Rock Johnson.
And this year it is hosted by
Jason momoa, Aquaman.
I know.
Fitting.
Yes.
And you can visit their website, which
we'll have linked, so that way you
guys can see the different videos,
podcasts and movies that they are
featuring for this week's, Shark Week.
So definitely check out all the stuff
they'll have.
I'm sure they'll have some pretty cool
podcasts.
I saw some of their videos already
too.
So now we want to talk about
sharks, all things sharks.
So I'm going to get started with
some fun facts and information about them.
So, sharks are a group of elasmobrink
fish characterized by a cartilaginous
skeleton, five to seven gill slits on
the sides of the head, and pectoral
fins that are not fused to the
head.
Sharks range in size from the small
dwarf lantern shark, a deep sea species
that is only 17 CM in length,
to the whale shark, that is the
largest fish in the world, which reaches
approximately 12 meters, or 50ft in
length.
So that's a really big one.
Sharks are found in all seas and
are common to depths about 2000 meters.
They generally do not live in freshwater,
although there are a few known exceptions,
such as the bull shark and the
river shark, which can be found in
both seawater and freshwater.
Sharks have been in existence for over
400 million years.
There's actually fossil evidence that
dates back to 450,000,000 years ago, but
only scales have been found, not teeth.
If the scales did happen to come
from an early shark, then those sharks
could have been toothless.
Sharks have a covering of dermal denticles
that protects their skin from damage and
parasites, in addition to improving their
fluid dynamics.
Dermal denticles, also known as plecoid
scales, are pointed and tooth shaped.
Shark teeth are embedded in the gums
rather than directly affixed to the jaw,
and are constantly replaced throughout
their life.
Multiple rows of replacement teeth grow in
a groove on the inside of the
jaw and steadily move forward, similar to
a conveyor belt.
Some sharks lose 30,000 or more teeth
in their lifetime.
The rate of tooth replacement varies from
once every eight to ten days to
several months.
In most species, teeth are replaced one
at a time, as opposed to the
simultaneous replacement of an entire row,
which is observed in the cookie cutter.
Shark shark skeletons are very different
from those of bony fish and terrestrial
vertebrates.
Sharks and other cartilaginous fish, such
as skates and rays, have skeletons made
of cartilage and connected tissue, meaning
they have no bones in their bodies.
Cartilage is flexible yet durable, yet it
is about half the normal density of
bone.
This reduces the skeleton's weight, saving
energy.
Because sharks do not have rib cages,
they can easily be crushed under their
own weight on land.
That's why you don't see shark skeletons.
It's because they're made of cartilage,
just like a nose.
Our nose and our ears are also
made of cartilage, so when you look
at a skull, it doesn't have ears
and it has a little opening where
the nose is.
However, their jaws are made of calcified
cartilage, which is why you do see
a skeleton for shark jaws.
The jaws of sharks, like those of
Raisins Gates, are not attached to the
cranium, which is the top part of
your skull.
The jaw surface, in comparison to the
shark's vertebrae and gill arches, needs
extra support due to its heavy exposure
to physical stress and its need for
strength.
It has a layer of tiny hexagonal
plates called tesseray, which are crystal
blocks of calcium salts arranged in a
mosaic.
This gives these areas much of the
same strength found in the bony tissues
found in other animals.
A shark's bite can generate 40,000 PSI,
or pounds per square inch of pressure.
Unlike bony fish, sharks do not have
gas filled swim bladders for buoyancy.
Instead, sharks rely on a large liver
filled with an oil that contains squalene,
which is a colorless oil, and their
cartilage, which is about half the normal
density of the bone.
Their liver constitutes up to 30% of
their total body mass.
The liver's effectiveness is limited, so
sharks employ dynamic lift to maintain
depth while swimming.
Sand tiger sharks store air in their
stomachs, using it as a form of
a swim bladder.
Bottom dwelling sharks, like the nurse
shark, have negative buoyancy, allowing
them to rest on the ocean floor.
Extracts from a shark's gallbladder are
used in the treatment of both cataracts
and acne.
I did not know.
That is different.
Most sharks are cold blooded, or more
precisely, foikilothermic, meaning that
their internal body temperature matches
that of their ambient environment.
Sharks have keen olfactory sensors located
in the short duct between the anterior
and posterior nasal openings, with some
species able to detect as little as
one part per million of blood.
In seawater, sharks have the ability to
determine the direction of a given scent
based on the timing of scent detection
in each nostril.
Their eyesight is well adapted to the
marine environment with the help of a
tissue called a Tatum lucidum.
This tissue is behind the retina and
reflects light back to it, thereby
increasing visibility in the dark waters.
Sharks are colorblind, uses a composition
of the photoreceptors in their eyes.
Their sight lines span nearly 360 degrees.
They have only two blind spots, one
in front of the snout and the
other directly behind the head.
Sharks use of the ampiocal Renzini
electroreceptor organs inside their body
to detect the electromagnetic fields that
all living things produce.
This helps sharks, particularly the
hammerhead shark, find prey.
The shark has the greatest electrical
sensitivity of any animal.
Several species of sharks are apex
predators, which are organisms that are at
the top of their food chain.
Select examples include the tiger shark,
the blue shark, great white shark, mako
shark, ghoster shark, and the hammerhead
shark.
Is that why they do the nose
thing or the head?
Have you ever seen, like, people who
are trained swimming with sharks and the
shark will approach them and then they'll
put their hand right between their eyes
on top of their head or like,
right on their nose and push them
away?
Okay, so why would you ever want
to be that close to a shark?
To touch mean, that would be kind
of cool.
I would just say some sharks are
nice.
I would just prefer to be trained.
Yeah, exactly.
I think nurse sharks because when we
went to the Bahamas one time, there
was like this whole area of nurse
sharks that would sit around by the
dock and people would feed them off
the docks.
And they were supposed to be relatively
gentle.
They're big, they're large, but they're
not supposed to be aggressive like the
bull shark, which is like or the
tiger.
Yeah, that might be why.
So that way it's like, see me.
But maybe I hit something.
Turn around.
Yeah.
Let's talk a little bit about shark
conservation, because that's ideally what
the whole idea behind Shark Week was,
was to talk about shark conservation.
The ODS of being attacked and killed
by a shark are one in 3,748,067.
Despite what many may think, shark attacks
are very rare.
On average, there are 70 to 100
shark attacks per year, and this is
across the world, and only five to
15 of those result in someone expiring.
By contrast, the ODS of being struck
by lightning are way higher one in
78 746.
You are more likely to die from
falling out of bed than because of
a shark.
600 Americans a year die by falling
out of bed.
And on average, less than six people
are killed by a shark every year.
Worldwide, out of the known species of
sharks, only 20 are known to attack
humans.
There are more than 470 different species
of sharks.
By comparison, humans kill 100 million
sharks every year, or
11,000 sharks per hour.
So by the time you're done listening
to this podcast, probably about 5000
sharks have been killed by humans.
Sharks are caught by humans for shark
meat and shark fin soup.
Many shark populations are threatened by
human activities.
Since 1970, shark populations have been
reduced by 71%, mostly from overfishing.
Fishermen capture live sharks, fin them,
and then dump the finless shark back
into the water.
Shark finning involves removing the fin
with a hot metal blade.
The resulting immobile shark soon dies
from suffocation, or predators.
Poachers illegally fin millions each year.
This is a really popular dish in
Asian cuisine.
It's called shark fin soup.
And so they just waste the rest
of the shark and the shark uses
its fin to help it.
It's like it's a rudder, so it
helps it to have the direction of
where it wants to swim.
So once they take off the fin,
then the shark can't do anything.
No.
Yeah, it's just like just dead in
the water, basically.
California, Delaware, Hawaii, Illinois,
Maryland, Massachusetts, New York, Oregon,
Rhode Island, Texas, Nevada, Washington,
and three U.
S.
Territories.
American, Samoa, Guam, and the Northern
Mariana Islands have enacted laws that
prohibit shark fin trade outright, making
it illegal to sell, trade, or possess
shark fins within their borders.
We might not see Florida there.
They have not.
So there's quite a few states still.
That have not done so.
Interesting.
So one cool shark we want to
talk about are whale sharks.
Whale sharks are approximately the size of
a school bus, like JC mentioned earlier,
which we are in right now.
And they are huge.
They can be up to 40, 50ft
in length and also weigh 20.6 tons,
making them the largest fish in the
sea.
Despite their massive size, the whale
shark is a filter feeder that can
neither bite nor chew.
Although its mouth can stretch to 4ft
wide, its teeth are so tiny that
it can only eat small shrimp, fish
and plankton.
By using its gill rakers as a
suction filter, it's thought that less
than 10% of whale sharks born survive
to adulthood.
But those that do may live up
to like 150.
Whale sharks can be found in all
temperate and tropical oceans around the
world except the Mediterranean Sea.
They can migrate thousands of miles to
different feeding grounds, but only at a
slow swimming speed of around 3 mph.
There was also a whale shark that
was spotted off the coast of Destin
on July 17, which that was when
Shark Week started in 1988.
That same day.
I didn't think about that.
Interesting.
And you can check out the video
from Wear, ABC, Three News, Pensacola on
their Facebook and we'll have it linked
in the description of the podcast episode
as well.
I also recently saw that Alex Fogg
and their team is trying to go
and put markers on the whale sharks
so they can track their movements like
as they're in the area there's.
That great white shark.
Isn't her name like Katie or something
and she has a tag on it
and you can follow her movements too.
Yeah you could probably just google Katie
the great white shark and know where
she moves and what her range is.
Yeah.
Another thing wanted to mention was about
shark's teeth.
So I used to live down in
Gainesville, I went to school there and
one of the things we did and
just to pass time and to get
out of the books was to go
actually look for shark's teeth.
If you don't know where Gainesville is,
it is central Florida.
It's not on either of the coasts,
it's in the middle and there are
sharks teeth there.
We specifically went to Loblollywood's
Nature Park and it's many of the
parks that are around Hogtown Creek but
Hogtown Creek is where you're going to
see those and it's just a small
creek that cuts directly through the city.
Loblolly woods has a few miles of
like hiking and biking, jogging trails but
those creeks you can go and sit
in and it is definitely the star
of the show.
It's nice and cold, it feels good
when it's hot and swampy in Gainesville
and it also plays a vital role
in Gainesville's ecology and it ultimately
flows into the aquifer from the
Gainesvilleans draw in their drinking
water.
The creek itself has mostly a sandy
bottom but the pebbles will gather in
the bins where the elevation of the
creek's bottom changes.
So if you grab a handful of
the pebbles and you carefully start to
look through them, within about 15 minutes
you can find probably five to 1015
tiny shark teeth.
You do have to look really closely.
Sometimes you can even take a strainer
or a sieve and scoop it up.
Basically why these shark's teeth are
there though a little bit about that.
About 10 million years ago according to
the experts, the creeks in Gainesville cut
into a phosphate layer under the soil
which formed when central Florida was
first rising out of the ocean.
That layer holds the fossilized remains of
aquatic animals and land animals.
Saber teeth have also been found in
the area.
For example, I've also found a couple
of skate teeth as well.
In fact, Gainesville is one of the
best places in the state to look
for fossils, especially shark's teeth.
Hogtown Creek, Ratlesnake Creek and many
of the other places are just covered
in shark's teeth.
The best time to go and hunt
for these shark's teeth is right.
After a heavy rain, the water level
will rise and leave the less dense
fossils right on the top and the
more dense rocks down at the bottom.
And the best place to look for
these is where the creeks are bending.
But it's important to know that when
you're going and looking for these things
that you are aware of how much
sediment you're moving around and how much
you are digging and scooping out of
the sand.
It's important that we don't want to
leave too deep of holes because it
can again mess with the sediment and
then that can ultimately mess with the
water quality of the creek, which you
do not want to happen because like
we mentioned before, the people drink that
water there.
If you are looking to do a
shark based activity, we briefly talked a
little bit about how sharks have an
oily liver which makes them buoyant.
And buoyancy is the ability to float
in water or other fluids.
But sharks need to put effort into
remaining buoyant, though in fact, they
really can't stop swimming or they will
sink.
So most bony fish have a swim
bladder, which is the internal organ
that's filled with gas, that helps the
fish float without having to swim all
the time.
But sharks, which are the Elasma branch
fish, they don't have the swim bladder
to help them with the buoyancy.
And the reason is because sharks can
rapidly change depth without bursting an
air filled swim bladder.
So if they had a swim bladder
and it was full of air and
they dove down really deep, that would
bust and then they would drown.
Essentially though the sharks float
because of that oily liver in water,
it will allow them to kind of
stay above.
So a little activity you can do
is get a water bottle or a
balloon and fill one of them up
with oil and the other one, just
leave it with air as your air
filled bladder and then sit them both
in a bucket of water and observe
what happens.
If you want to take it a
little step further, you can take another
water bottle or balloon, fill it up
with water, put that in the bucket
of water as well and watch that
sink down to the bottom of your
bucket.
Super fun to see.
And if you're looking for something a
little bit more fun to do with
your kids, you can even give them
some sharpies and they can draw shark's
teeth or fish on the side of
the bottle or balloon.
There are a couple of other reasons
why sharks can float as well.
They are made of cartilage rather than
bone, like we mentioned before, and that
is also lighter than bone.
The side fins are also somewhat like
wings, while the tail fin generates
constant movement, pushing the shark
forward.
The fin will lift the shark while
the tail moves the shark through the
water.
And however, a shark cannot swim
backwards, only forwards.
So I just looked it up and
there's a shark tracker and it's an
app.
You can get it on your phone
or you can check it out on
the Internet, and it's Ocearch.org.
And I just pulled the map up
and look at the sharks that are
right around Florida.
It looks like there's one over just
south of Louisiana.
There's one maybe right by Jacksonville,
and there's a couple of them down
by the bottom of Florida around the
Keys area that they're tracking that just
all pained recently.
So I think that's kind of cool
and just an extension of finding out
what sharks live where we know that
here we have hammerheads, we have bull
sharks.
Those are probably the ones that people
talk about most often.
And I know that we just recently
there was a picture on social media
of a hammerhead that was on the
beach somewhere.
They were taking a picture of it.
And I know there's been hammerheads that
have like just cruised through Crab
Island.
When people are out, know they're there,
but just remember that they were there
first.
It's their home, it's their visiting unit.
Right.
We are the guests and we are
entering their space, and they're only
typically will feed in dusk and dawn,
which will tell you, please be careful
when you're in the water, especially
around dusk time, because that's when or
if you see fish schooling together.
Don't go swim into the middle of
a school of fish because that's exactly
what they're looking for.
You'll also be seen as a fish.
Yeah.
So we do have a couple of
shark jaws here at the science center.
So we have a new bones exhibit.
And again, we said that the jaw
is the only part that lasts because
it is calcified cartilage.
So it does have more of a
bone type structure.
The rest of the shark is cartilage,
and so it would just disappear.
It breaks down and goes away.
And then we also have a couple
of sharks that are outside made out
of wood, but they're in our little
ocean area right next to our pontoon
boat and have some different information
about sharks that live in our area.
And a hammerhead shark photo op.
Yes, that's true.
You can yourself inside the mouth with
the hammerhead.
Yes.
So definitely check those out.
So we want to close out with
a few shark pun.
So are you guys ready?
Yeah, I'm ready.
Okay.
Stay, Jostum.
Oh, that's cute.
What do sharks do when they have
a big choice to make?
Choose wisely.
Don't debate me.
You won't win.
Despite what type of shark are the
Shadiest sharks?
Hard shark, I think if you sort
of think about that.
Sharks kind of like snakes.
They're always like the bad guys, so
they always get a bad rap.
And actually they're incredible creatures.
They've been around for millions and
millions and millions of years and haven't
really changed that much over the course
of time.
Again, we are just decimating the
population of them worldwide.
So we don't even know what's going
to happen, as what we do influences.
Shark populations, but would also
influence every.
Other population if they're apex predators
as an apex predator.
So everybody have a great Shark week
and just keep in mind that they
are trying to sensationalize the sharks on
the television programs.
Most of the movies, I'm sure, right.
Because they want you to watch.
If you watch those, be sure to
laugh because it's funny that they're so
inaccurate.
So that is all for our podcast
this week.
We'll see you guys in two weeks.
Bye.
Thanks for listening to this week's
episode of Cultivate Curiosity.
If you have any questions, feel free
to email us at social media@ecscience.org.
Tune in for our next episode two
Weeks close.