All language subtitles for Attack and Defend Series 1 6of6 Underwater Warriors 1080p

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The eternal underwater dance
of predator and prey

is as hypnotic
as it is horrific,

but one thing's for certain,

in the water,

you don't have to be big
to be an effective predator.

That said, being big certainly
doesn't hurt.

These are water warriors.

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Sharks.

They are some of the most
notorious hunters

in the history of the planet.

They are predatory works
of art,

400 million years
in the making.

Their lethal reputation
strikes fear

deep into the hearts
of beachgoers.

Even though the odds
of getting attacked by one

are extraordinarily low.

Statistically,

you're more likely to be killed
by a vending machine

than a shark.

But humans are the exception.

For prey in the sea,
the nightmare is real.

Sharks are actually
the perfect predator

in the marine ecosystem.

Sharks have a lot of things
going for them,

they've got speed,
they've got perfect senses.

So, most sharks
have excellent vision,

we think that most sharks
can see in color,

they certainly see
in high contrast,

they've excellent sense
of smell.

The first thing that
they're gonna probably key-in on

is sound and vibration

that travels farther,
it travels faster.

Once they get into the
immediate area

they're then looking for
the smell, they pick that up.

The cool thing with sharks
is they've got two nostrils.

If they smell blood over here,
they go that way,

if they smell blood over here,
they go that way.

Razor-sharp senses are
a huge part of their arsenal,

but sharks have a sixth sense,

and it pushes
their hunting prowess

into the realm
of the supernatural.

All living things give off
a very faint electric charge,

and sharks use
their gel-filled pores

called Ampullae of Lorenzini
to pick up electric current.

These are pores on every

snout of every single
shark species.

When hunting,
at the moment of attack,

great white sharks
roll their eyes

back into their sockets
to protect them.

They're blind in that moment,

they're using that network
of pores

to then determine what to bite,

because they're getting
that electric cue.

And that
whole network of senses

makes them truly
the perfect predator.

After the shark locks onto
its target,

speed and brute strength
take over.

Some species can strike
at speeds of up to

55 miles per hour.

Six or seven rows
of serrated teeth

tear flesh and break bones,

leaving their prey
either dead or disabled.

And the wide diversity
of sharks

means that there are plenty of
different things on the menu.

They filled all niches
of the marine ecosystem,

some eat small little shrimp
crawling around the bottom,

some eat large marine mammals
by zipping through the water

at extreme speeds,

being able to takedown animals
with serrated teeth.

The two biggest species
of sharks,

the basking shark
and the whale shark

are actually filter feeders.

So rather than
just kinda spending

all this time and energy

hunting and looking
for that sole meal

they're constantly feeding.

They flare their gills open,

they have gill rakers
on their gills

that actually trap that krill

and then they're able to
get that off of their gills

and use it for nutrition.

No matter what
the size of prey,

a shark's instinct to find food
and thrive is undeniable.

For sand tiger sharks,

the killer instinct kicks in
before they're even born.

They have
intrauterine cannibalism,

the pups develop
inside the mom's uterus,

they have eggs that hatch out.

And kind of the first shark
to really hatch out,

they start feeding on
all their brothers and sisters,

and then, one shark is born
from each uterus.

By the time they've been born,

they've eaten 50 to 100
of its siblings.

Mastering your craft
before birth

is yet another
survival advantage

of this ancient lineage

and another reason
sharks have been on the planet

for hundreds of millions
of years.

They kill
from the day they're born

until the day they die.

They're immaculate specimens
of predatory power.

Apex predators
in every way imaginable.

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The ocean, it makes up about
71% of the Earth's surface,

and contains 97% of the water
on the planet,

but 95% of it
is still unexplored.

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Below the surface

are some of nature's
most stunning works of art,

fish shoals.

Millions of fish harmonized
and moving in unison

are a beautiful
and mysterious sight.

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If you come upon
a fish shoal,

what you'll find
is a group of fishes

that are typically moving
in the same direction,

and so in that way,

the shoal looks like
a co-ordinated whole organism,

as opposed to many individuals
that behave differently.

So there's synchrony

amongst individuals
moving in the group.

It's a mesmerizing display
and that's exactly the point.

The ocean is a dangerous place,

to defend themselves
and survive,

fish find strength in numbers.

Among all fish,

about 80% of families
have members that join shoals,

and they group together
for many different reasons.

The main selective
pressure in nature

for grouping or shoaling
is from predators.

So, individuals then
will form a group

to reduce their individual risk
of being caught by predators.

A predator can easily home in
on a single lonely fish,

so as a group,

fish increase
their rate of survival

by diluting the possibility
of being the chosen one.

Shoals can be two fish
or they can be millions,

but the bigger the shoal
the better.

A shoal also experiences
an increased ability

to problem solve.

We now know that
animals that live in groups

including fish,

can have increased or enhanced
accuracy and precisions

of decision making.

In other words,
which area to explore

and which orientation
when you're migrating

are all improved
when you join a group,

and also, improvements increase
with group size.

And shoals not only look
like a single organism,

they act like one too.

Split second decisions
made by the vanguard

shoot through the shoal
like lightning

in a phenomenon called
"swarm intelligence".

Swarm intelligence is where
the movement of a group

in one direction or speed

is dictated by first the
movement of a few individuals

the predictive directions
that is so called leaders.

And then, once you have a
sufficient numbers of followers

reaching a certain
threshold number

then the entire group will move
in that direction.

It doesn't mean that the move
is intelligent per se,

but that there is
collective decision making.

Grouping together also
increases a fish's success

in finding a mate.

With plenty of fish around them,

they don't need to search
the sea for a partner.

Another reason fish gather
is to find food.

Food sources in nature
are not evenly distributed,

and so, individuals and--

that form members of shoals
can find food faster,

because there have many eyes
looking for food.

But when
fish find food together,

they have to share that food

and this increases competition
for resources.

Some species have been known
to form smaller shoals

when food is near,

and larger ones
in the presence of predators.

Shoals come in all shapes,
sizes, and colors.

The colors have been known
to contribute

to a phenomenon called
the confusion effect.

When all members of one shoal
look similar

predators can experience
perceptual confusion,

slowing down their attack

and giving fish the time
to get away.

Yet, fish are constantly
changing shoals.

Joining the right shoal
is critical,

a fish must blend in with
the rest of their shoal mates,

joining the wrong shoal

could have
unfortunate consequences.

But studies show

that they're excellent
at choosing shoal mates

with similar traits
to themselves.

What I found most fascinating
about fish shoal

is the range or diversity
of group sizes that you find

and the types of species
that do shoals,

ranging from very small fishes
to very large fishes.

And they're not only found
in the deep blue sea.

You can find fish shoals
in all kinds of aquatic habitats

ranging from small ponds that
you might find in your backyard

to small rivers and lakes,

and up to,
of course, the open ocean.

So there's a huge diversity of
ecological functions

of fish shoals
that we know about.

Ocean predators
are highly evolved

and shoals offer
a creative defense,

because whatever your size,
shape or color,

there is strength in numbers.

Fish shoals
are a truly captivating example

of survival in the sea.

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They look like something
from outer space;

they're born with three hearts,
two for their gills

and one for the rest
of their bodies.

Cuttlefish,

unlike humans
and all vertebrates on Earth,

have no hemoglobin
in their blood cells.

Instead, they're filled with
copper-based protein,

meaning their blood is green
like a movie alien.

As strange as they look,

cuttlefish are also the oceans'
sneakiest predator,

a truly gifted
and sometimes a deadly imposter.

Their very name is a decoy.

Cuttlefish are not really fish
at all,

they're molluscs
like the octopus and the squid.

They belong to a family
of cephalopods

that's been around

for hundreds of millions
of years.

And at that time, they've
learned a thing or two

about avoiding been eaten
by arch enemies,

mainly dolphins, sharks,
and seals.

For one thing, their eyes
are highly developed

among the most developed
within the invertebrates.

But, when trouble comes
a knockin',

it's not just their eyes
that can save their skin,

it's also
their built-in jet packs.

They have jet propulsion.

So, they can suck in water
in their mantle cavity--

This is a cavity
inside their body

and they can push this water
out the back.

Like squeezing a bubble,
it moves forward

with the water squirting
backwards.

Their jet engine escape
comes with a neat trick

they share with their cousins,
the octopus.

Black ink.

So they burst forward
through jet propulsion,

and they leave this sort of
cloud of black ink behind them

to confuse the predator
that might be chasing them.

Their greatest trick of all
however,

is their incredible ability to
seemingly vanish like a ghost.

Cuttlefish are the chameleons
of the sea,

their highly-developed
nervous system

allows them to change color
in almost the blink of an eye.

The speed of change
is so spectacular,

no other animal in the ocean
can be equal to cuttlefish.

What allows them to
change color

is what happens to millions of
little cells below their skin

called chromatophores.

And these chromatophores
are rapidly reacting

to tiny, tiny
muscle contractions around them

and these contractions
or extension

will change the density
of the color.

Their light-reflecting
pigment cells can combine

to create hundreds of colors.

So, as it goes from
one micro habitat to the next

it can change subtleties
of its pattern.

So, in some circumstances it can
accurately background match.

Cuttlefish can also match
textures

and even patterns
from its background

to create what is known
as disruptive coloration.

Disruptive coloration
is the ability to trick

the eye of the predator.

So, it's where you can have
high contrast, edge colorations

that intersect the boundary.

And this breaks up the shape
and edges of an animal.

Using their flexible arms

along with shifting colors
and patterns,

the cuttlefish can pose
as a plant,

a sandy rock or a scary fish,
but that's not all.

Not only can cuttlefish adapt
to conceal themselves

from their predators,

they also use their
rapid-changing of skin color

to communicate
between one and another.

Because cuttlefish
aren't tricked

by one another's camouflage.

This visual communication
allows them

to pass on secret warnings
amongst themselves

without the predator
having a clue.

But cuttlefish
aren't always in defense mode...

...like all cephalopods
they are predators.

Always on the lookout for
crabs, fish, and small shrimp,

cuttlefish have
perfect camouflage

and sneak up on their prey
using their powerful arms,

and pair of tentacles
tipped with suckers,

and mashing teeth to kill.

These arms are powerful,
thanks to strong muscles,

also with the suckers,

which are very powerful
to hold on to a clam

or a prey of some sort.

And then,
they bring it to the mouth,

and they will inject the poison.

The poison they inject
is neurotoxic

and comes from their saliva.

The mouth of a cuttlefish
isn't technically a mouth;

it's a hard crushing beak
like that of a parrot.

Whatever you wanna call it,
the result isn't very pretty.

Among all invertebrates,

cuttlefish are considered
some of the most intelligent

with a strong ability
to learn and adapt.

It's that intelligence
and that knowledge

that has kept this fascinating
lineage alive on this planet

for hundreds of millions
of years.

Crocodiles.

With that sly smile
they lurk with patience,

waiting for some
unfortunate prey to wander by.

And then,

a set of powerful traits
of these creatures

skillfully capture their dinner.

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Crocodiles are amphibious,

which means they live both
in water and on land.

They're frighteningly
quick swimmers.

On land, however, crocodiles
are generally pretty slow.

They sort of bumble about
with these limbs

that are not very articulateable

and so, they really wouldn't do
very well

in the long distance chases
in the terrestrial environment,

which is where most of
their preferred prey are found.

So, their better strategy
is really just to hang back

on the edge of water,

wait for that prey
to get close enough,

and to pounce on them.

And the water is where the
crocodile truly shines.

This is where the
deadly predator hunts for fish,

molluscs, birds

or anything else that unwisely
happens to step into

its watery lair.

Crocodiles vary in size

from less than 5 feet
to almost 22 feet

and weigh more than
2,000 pounds.

Regardless of size,

all crocodiles have
one common advantage as hunters,

they are amazing swimmers.

The power and thrust
for their swimming

comes mostly from that
undulating tail,

which is very long
and very muscular,

giving them the ability
to sprint at great distances

and speeds underwater.

Using their powerful tail
for propulsion,

some species can reach speeds
of more than 15 miles an hour.

To help it underwater,

the crocodile has developed
a nostril opening

with a membranous flap
that shuts tight when it dives,

keeping the water out.

Another flap closes off
the mouth cavity,

so it can breathe
even when the mouth is open.

What makes the crocodile
such a skillful hunter

is its innate ability
to sneak up on its prey.

Their eyes are on the top
of their head,

the ears are on the top
of their head,

the nose on the top
of their head,

in a perfectly straight line.

So no matter how big they are,

when they're laying
in the water,

that's all you see sticking out.

But not all crocs are content
with just eating fish

and molluscs.

For those,
like the Nile crocodile,

their large bellies require
much bigger game,

like wildebeest, deer,
and even lions.

To be successful
with these enormous animals,

crocodiles rely
in their special sense organs.

A crocodile's sixth sense.

Around the nose
of the crocodile,

they have little nerve endings

that tell them when
something's touching or breaking

the surface tension
of the water.

And as soon as that happens,

they'll then explode out
of the water,

lunging out to try and grab
whatever they can.

And there would be
an unsuspected prey item,

like a zebra
or wildebeest

or whatever it is,

they'll grab it and pull it
straight into the water.

Whether sneaking up
in ambush, or chasing
down its prey,

the crocodile's weapon of choice
are its jaws.

They can apply as much as
5,000 pounds of pressure.

That's six times stronger

than the bite of the notorious
great white shark.

Because their jaws
are not very articulateable,

meaning that they can
open and close,

but they don't really
move around in any other plane.

The only way for them to able

to get pieces off
of a larger animal

are to tear it off
by thrashing their body about.

To protect their eyes
during these violent maneuvers,

the croc has a third eyelid
known as a nictitating membrane.

In addition, the skull itself
offers protection.

When they close their eyes,

the bony plates of the eyes
will not only protect the eye,

but the eyes will even drop down
into a socket,

which will protect them even
further from damaging the eyes.

A lesser known aspect
of crocodiles

is that they are very smart
and cunning.

A croc will sometimes work
with others

in what is known as
co-operative hunting.

One co-ordinated strategy

is for
several crocs to wait in line

as prey like the wildebeest
cross the river

waiting to ambush
the small or injured,

whoever happens to cross
their path.

(♪♪♪)

Crocodiles have roamed the Earth
for roughly 200 million years,

their specialized hunting skills
have allowed them to outlive

even the mightiest dinosaur.

(♪♪♪)

From powerful sharks,

to mysterious
and beautiful fish shoals,

the underwater dynamic between
predator and prey continues.

Evolution is on display
in these clever creatures

that are using all their skills
to survive.

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