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the great white shark they are the
largest predatory fish on the planet and
as such stand at the very top of the
food chain in the oceans they are built
for killing and without a doubt one of
the most successful predators of our
time despite this they are also deeply
misunderstood animals movies like Jaws
turned sharks in particular great whites
and two bloodthirsty calculated
man-eaters and probably into one of the
most feared animals in the world but do
they really deserve a bad reputation and
what even makes them such dangerously
effective predators that's what we will
discuss today but before we get started
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deny
great whites are dangerous animals they
are highly specialized killing machines
and perhaps the ultimate predators of
the ocean but are they also the savage
men eaters many people think they are
statistically yes great whites are the
most dangerous predators for humans in
the JumpShip in the US where most human
shark encounters are recorded each year
sharks have bitten around 650 people
between 2000 and 2015 15 of them fatally
tiger boa and great white sharks are
responsible for the largest number of
these shark bites but as tragic as each
of these incidents is do these
statistics really paint the picture of
sharks as fearsome man-eaters great
whites are some of the largest predators
on the planet with an average weight of
more than half a ton
in an average length of 4 to 5 meters
top speeds of almost 60 km/h and perhaps
the strongest bite in the animal kingdom
no animal and the menu is safe if that
would include humans the number of
deaths caused by shock points every year
would certainly not be single-digit but
probably go on to the thousands
considering the number of people that
visit the beach year-round in the US
alone it's around 50 million people per
year even though almost the entire US
calls the shark territory with this much
potential prey the few dozen shark bites
that are recorded every year worldwide
don't really support the picture of the
savage man-eating killer because for
great white a human in the water is
about as helpless as a fish on land and
certainly easy prey they are after all
adapted to hunt prey that is much bigger
and more difficult to take down one of
the most amazing of these adaptations is
the battery of sensors they have at
their disposal the sense of smell is
probably the most famous of them all
even though this ability is of an
exaggerated most likely to make them
even more terrifying it is still
unparalleled in the oceans they can
detect specific chemicals such as blood
proteins in minut concentrations
possibly as low as one part per 10
billion that's the equivalent of five
drops of blood in an Olympic sized
swimming pool if the currents carry the
particles in the right direction this
means they can detect wounded prey from
as far away as half a kilometer
one of the senses that is often
overlooked and is perhaps the more
accurate is the sense of hearing it is
much more sensitive than that of humans
and is especially adapted for detecting
low frequency sound below 40 Hertz
including infrasound this allows them to
hear the low frequency pulses caused by
tiny water vibrations struggling fish on
marine mammals make and over great
distances because sound travels faster
and further in water than in air great
whites can therefore hear the movement
of potential prey from sometimes over a
mile away
despite the reduced visibility
underwater the great whites eyesight is
equally good they can probably see as
well under water as we can above the
surface and even in color array ability
and sharks which are typically
colorblind
additionally they possess the same
reflective layer behind the retina that
cats do this allows light entering the
eye to strike the photoreceptors twice
which gives sharks the ability to make
of their prey and almost perfect
darkness but aside from these three
senses that almost all vertebrates have
and which are already highly developed
in sharks they also possess two
additional complimentary senses the
first is the lateral line system a
sensory organ you could find an almost
all fish it consists of a series of
fluid-filled canals running just under
the skin along the flanks of the body
and over the entire head with these
canals they are able to feel
low-frequency pressure changes in the
water this gives them yet another way to
detect find water movements caused by
the swimming motions of nearby prey and
finally there is the ability of
electroreception
this is a trait that is almost unique to
sharks and their relatives and it allows
them to detect the weak electric fields
produced by the bodies of all living
organisms through a series of
specialized sensory cells connected to
the surrounding water by over a thousand
jelly-filled paws distributed over the
shark's head
the Sharks are able to locate prey from
about a meter or three feet away this
helps a shark keep track of its target
rest before it bites it when it's hidden
in the blind spot in front of its nose
or when it's otherwise hidden from view
they probably also use it for navigation
by orienting along Earth's magnetic
field
all this makes great white sharks
without a doubt one of the most
dangerous and successful predators on
earth and a human would certainly be
easy prey for them and yet the number of
fatal shark attacks by great whites is
minimal almost every animal that you
would think could kill a human kills
more people every year than sharks lions
check Tigers check wolves check snakes
snails
elephants dogs jellyfish hippos bears
bees scorpions cows crocodiles even
horses it is more likely he will drown
before ever getting bitten by a shark
even getting hit by lightning is more
likely one reason is that we are simply
a two bony meal for shock because great
whites have a very slow digestion by
having a comparable high metabolism they
are actually very picky eaters they need
gourmet food pray with a high fat bone
ratio like marine mammals which have a
thick layer of blubber humans simply
have too little fat and too much muscle
and bone to be a viable food sauce if
anything we would probably cause them
serious and digestion
at which point that would likely just
vomit us back into the ocean sharks can
do that it's called gastric aversion
it's when a shark turns its stomach
inside out extending it from its mouth
and ejecting unwanted contents like
bones or low-quality meat of the stomach
to make room for better food but if they
don't view us as prey then why do shark
bites happen there's a lot of
misinformation about this too for a long
time we thought that sharks simply
mistake us for their usual prey this
however seems unlikely to be the case
given their incredible array of senses
the attack pattern also doesn't support
this notion red whites usually attack
seeds with tremendous force and speed of
meketa pouring ourselves up to three
metres in ten feet out of the water
this is not how attacks on humans
usually take place in most cases the
Sharks approach at a relaxed pace take a
bite or two and then swim off again new
research on shark behavior suggests that
these bites are in most cases simply the
result of their curiosity just like most
animals that have almost nothing to fear
in their environment sharks are very
curious animals when they see something
that I don't know they like to
investigate it and since they neither
have arms no legs the only thing left
that they can use to get a feel for
something is
their mouth a bite tells them everything
they need to know about an object so if
anything it's this curiosity what makes
them dangerous to us and not their lust
for human flesh the second reason why
shark bites happen is a similarly normal
behavior for wild animals competitive
behavior in the wild the strongest most
dominant individuals tend to get the
best food and while sharks don't have
territories in sense that terrestrial
predators do they are still very
territorial especially in areas where a
lot of sharks congregate for instance
around where carcass the dominance
hierarchy needs to be established to
determine who eats first
great whites do this in a number of ways
despite sharks generally being lone
predators we have already identified at
least 20 distinct social behaviors that
help them establish social rank and
avoid physical conflict parallel
swimming for instance here two great
white swim side-by-side to figure out
who's bigger another way is a little
splash fight two or more sharks swim to
the surface and splash each other with
their tails the shark that makes the
most of biggest splashes wins great
whites even play chicken
they swim at one another and the first
to swerve loses in rare cases if all
these peaceful methods have proved
futile they take each other to
ultimately figure out who's stronger
once the dominance hierarchy is
established feeding is generally orderly
and well behaved as each shark patiently
waits for its turn these complex social
behaviors show that great whites aren't
just dumb killing machines but in fact
very intelligent animals humans that
invade the habitat can sometimes the
meloni be seen as competitors especially
in the vicinity of large schools of fish
or sea colonies in rare cases this might
provoke a bite to try to chase us off
the charts almost never bite to kill can
also be seen in the shark bite
statistics
as the number of fatal bites is really
low compared to the number of non-fatal
ones even in cases that unfortunately
ended in death it was usually the
consequences of the bite most commonly
the blood loss that were the cause of
death and not the attack itself because
for the fragile human body even a single
shark bite will of course often result
in serious injury or even loss of nails
hopefully by now it has become clear
that great whites are not the
bloodthirsty savage man-eaters film and
media typically make them out to be but
we also mustn't forget that sharks are
wild animals predators and even though
we are not on their menu there's always
a risk involved when you invade the
habitat if you're willing to look beyond
a bad reputation
they actually very fascinating animals
for instance great whites have extreme
regenerative abilities their wounds not
only here extremely quickly they are
also able to survive injuries that would
kill just about any other animal but
this ability goes beyond the physical
earlier this year a team of scientists
has completed its task to decode the
entire genome of the great white their
genetic code has revealed a surprisingly
high number of genome stability genes so
genes that are tied to DNA repair and
DNA tolerance these dreams help to
repair and prevent copy mistakes and
random mutations inside the DNA that
could otherwise lead to abnormal changes
in those cells these finds seem to
confirm a long-standing suspicion that
great whites are extremely resilient
against cancer and other age-related
diseases this however doesn't mean that
eating these sharks will somehow give
you the same abilities sorry Chyna much
of what we have covered this farce of
course not necessarily unique to great
whites and can be said about many of the
roughly 500 different shark species but
one characteristic of them is much more
unique and clearly makes them stand out
among other large species such as tiger
and bull sharks and that's the ability
to elevate the core body temperature
above that of the water
unlike most other sharks which are like
basing the all fish coat blooded great
whites and six other species all of the
order of mackerel sharks are able to
achieve the kind of warm-bloodedness
by holding the body temperature constant
at around 25 degrees Celsius and 77
degrees Fahrenheit they're able to
operate in both warm and very cold
waters and hunt by other large sharks
can't but how does it work in most
sharks the powerful red swimming muscles
are located along the flanks directly
below the skin the big dose the otter
the central running artery supplies them
with a necessary oxygen through a
handful of arterial branches afterwards
the carbon dioxide which blood is pumped
back to what's the heart most of the
metabolic heat Chuck's produce is
generated in these muscles while
swimming
but because water conducts heat 10 to 20
times better than air this heat is
normally immediately lost to the
environment resulting in no significant
temperature increase the great white
however has evolved in such a way that
it can greatly reduce this heat loss and
thereby maintain an elevated body
temperature this is only possible
through a series of modifications to the
structure of the swimming muscles and
the circulatory system the first
important change is that the red
swimming muscles are buried deep within
the shark's body on each side of the
backbone there's also much more than red
swimming muscle compared to the
predominantly white muscle of
cold-blooded fish is much more powerful
and produces more heat as a result it
does however require much higher
metabolism and more importantly a
greater supply of oxygen the additional
oxygen is provided by an large arteries
along the flanks of the fish that
redirect blood inward through a dense
bundle of smaller arteries and veins
this fine network is called Reed murali
which roughly translates to wonderful
net the central arrangement of the
swimming muscles means that far less of
the red muscle mass has direct contact
with the surrounding water which reduces
the immediate heat loss but much more
important is the extensive counter
current heat exchange enabled by the
dense array of veins and arteries that
supply the muscles with oxygen through
the countless small arteries and veins
then pass very close to one another
carrying blood and opposite directions
the Riccio act as heat exchanger because
of the intimate counter current blood
flow most of the heat is transferred
from the veins to the arteries and
cycled back into the muscles that
produced it originally
in contrast to a concurrent flow system
where the continued heat exchange
between two liquids will eventually lead
to an equilibrium that is somewhat in
the middle of the true original
temperatures in a counter current system
the exchanged heat is constantly carried
away pushed forth by a new cold blood
this means the upper stream will always
have the lower temperature and more heat
can be exchanged here in equilibrium is
only reached when nearly all the
original temperature difference was
exchanged
this makes counter-current exchange so
effective as nearly all the metabolic
heat in the venous blood is transferred
to the interior blood thus conserving
most of the muscles temperature this is
how great whites maintain a higher body
temperature and because of it they're
able to inhabit a much wider range of
environments with varying water
temperatures the additional red muscle
mass makes them powerful swimmers that
can travel great distances fast and
effortlessly even into colder want us
where the inner heat warms their brain
muscles and stomach and therefore allows
them to catch even Swift and agile prey
like marine mammals that would be
inaccessible for any cold-blooded
predators as you can see where'd white
sharks or sharks in general are truly
fascinating animals and more than just
terrifying sets of teeth his apex
predators they are also extremely
important for the ecosystem while I sit
on top of the food chain the health of
the ecosystem actually rests on their
shoulders they keep the balance and
without them the oceans ecosystem as we
know it would collapse
that's why protecting these animals is
very important of the approximately 500
species of sharks over 100 are
threatened
some even critically this includes great
whites various species of hammerheads
where sharks and basking sharks to name
a few but this isn't really surprising
given how many sharks are still killed
each year in attempts to make beaches
safer as bycatch by commercial fishing
results as trophy catches and for shark
fin soup a popular delicacy in China
only a few years ago it was estimated
that the number of sharks that are
killed each year is likely between 100
and 250 million that's a shocking 11
thousand that are killed every single
hour hour after hour day of
year after year and it will not stop
until almost every shark in the ocean is
dead unless we do something about it
thankfully a lot has already been done
in the past years and decades but
unfortunately shark conservation depends
on public acceptability and as long as
sharks are still viewed by many as
savage men eaters conservationists will
continue to fight an uphill battle to
protect these magnificent creatures
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