All language subtitles for Natures.Strangest.Mysteries.Solved.Series.1.Part.22.Elephants.in.the.Room.720p.HDTV.x264.AAC.MVGroup.org.eng

Narrator:
What's this sizzling sound

At the bottom of the ocean?

Nosal: What I can best describe
as, like, a crackling sound,

Almost like when you put
rice krispies into your milk.

Narrator: Why does this herd
of wild elephants

Check into the same hotel
every year?

Aryee: This clip is phenomenal.

It's incredible.
It's amazing.

Narrator:
And tourists in portland, maine,

Witness an astonishing sight.

A strange circle of bubbles
suddenly appear.

What's causing that?

Narrator:
Nature is awe-inspiring,

But sometimes it just
doesn't make sense.

Man: I have never seen
anything like this.

Our team of experts investigates
the weirdest animal behavior...

That's amazing.

...And the most unexpected
events...

What is causing that?

...Ever caught on camera.

My god!

These are...

August, 2016, western australia.

Above the waves, a peaceful,

Serene sea stretches
as far as the eye can see.

But below the surface,

That serenity is shattered
by a curious sound.

[ crackling ]

If you're out in the ocean
scuba diving,

You can hear
a lot of different things.

You can hear whales,

You can hear some fish,
but there's one noise

That you might hear
that's hard to explain.

What I can best describe
as, like, a crackling sound,

Almost like when you put
rice krispies into your milk.

And it gets louder and louder
as you approach rocks.

Narrator: What could be causing

This bizarre
underwater cacophony?

Nosal: If you're not familiar
with the area you're diving in,

You might think that
there's some sort of machine

Nearby creating this sound.

Maybe some sort of sonar
equipment from a nearby boat

Or even a submarine.

Narrator: Sonar was developed
during the first world war

To listen out
for prowling german u-boats.

It works by pinging out
sound waves,

Which bounce back off
solid objects,

Indicating both how far away
the object is and its size.

Nosal: There's two types of
sonar -- active and passive.

Active sonar actually emits
sound underwater at frequencies

That humans can even hear.

Narrator:
Cargo ships, fishing vessels,

And military forces
across the world all use it.

So, could sonar be the source
of the mysterious sound?

Riskin: The problem with
the sonar theory

Is that sonar tends to happen
at regular intervals,

You know, with a rhythm.

Nosal:
This is very different from the
actual crackling you're hearing,

Which is kind of this
constant chorus of white noise.

This doesn't seem like
it's sonar.

Narrator:
If the noise is not manmade,

Could it have a natural origin?

Nosal: We know that dolphins
vocalize with each other.

They also use echolocation,
where they will actually emit

Clicking sounds underwater.

Narrator:
A dolphin's echolocation works
in the same way as our sonar,

Helping them to navigate,
find prey, or detect predators.

Dolphins can actually
process hundreds and thousands

Of these clicks
every single second.

And in an environment
which is murky and dark,

This is really important.

So, could this sound
be coming from dolphins?

Riskin: Problem with that theory
is that sometimes,

This clicking noise happens
where there are no dolphins,

So it's got to be
something else.

Narrator: A military report from
the second world war

May provide the answer.

Off the indonesian coast,

An american submarine crew
heard the weird sound.

Fearing that the ominous crackle
might be a japanese device

Designed to disrupt their sonar,
they reported the incident.

After a year-long investigation
and hundreds of acoustic tests,

Baffled scientists
finally identify the culprit.

The solution is tiny.

It's this little nothing of an
animal called the pistol shrimp.

Narrator: So, how does
such a small creature

Make such a loud noise?

Meet billy the shrimp,

The fastest gun in the wet.

So, this pistol shrimp
doesn't look so spectacular

Until you pay
close attention to its claws.

Its claws are quite big
and quite strong,

And there's a loading mechanism

And a release mechanism
built into it.

Narrator:
First, the claw is cocked.

One half is shaped like
a plunger, the other a socket.

Nosal: But these parts are not
coming together

Like a clap making a sound.

Those two parts come together
with such force that water

Is displaced out of that area,
creating a bubble.

Narrator:
Blink and you'll miss it.

To see it properly,
we have to slow it right down.

The bubble bullet swells

And then implodes
almost instantaneously,

Generating a temperature
nearly as hot

As the surface of the sun,

A flash of light, a powerful
shock wave, and a loud bang.

Riskin: Pistol shrimp do this
for a couple different reasons.

One reason is that they might
want to stun prey.

If they do that "pah!" thing
in front of their prey,

It kind of knocks
them unconscious

So they can go grab them.

Nosal: But in addition to that,

It's thought to be used
as a means of communication.

Narrator:
The gun-toting crustaceans

Live in large colonies
hidden in the sea bed.

That means what we can hear
is the sound of thousands

All talking at the same time.

So you can imagine
all the chatter

Amongst all of these shrimp
in a reef.

That's what creates that
constant crackling sound that,

Again, seems like white noise

When you spend
enough time underwater.

Narrator: At the end of 1942,

When the u.S. Navy
finally learned

What was causing the noise,

They found a clever way
to use it to their advantage.

So, in world war ii, underwater,

Everyone was using sonar
to see each other.

And so by hiding where
there were pistol shrimp

Or playing the sounds
of pistol shrimp,

Those american submarines

Could acoustically hide
from the japanese boats.

That's really cool.

I like that a lot.

Okay.

♪

Narrator: November, 2017.

Mfuwe lodge in zambia.

The hotel is in busy season,

But not all the guests
have got a reservation.

Aryee: This clip is phenomenal.

It's incredible.
It's amazing.

You've got the world's largest
land mammal,

The african elephant,
walking through a hotel lobby.

That's a pretty amazing bit
of footage.

There has to be a reason

Why the elephants
are going through this lodge.

Midcap: They know exactly
where they're going.

They're going to a mango tree.

Narrator:
According to hotel staff,

This herd of wild elephants
turns up every year

Just as the fruit
becomes perfectly ripe.

The owners built the lodge
around the mango tree,

Unaware that this was one

Of the elephants'
favorite feeding grounds.

Oh, the baby --
he's just a few weeks old.

Hi, little one.

And this is at the end
of the lunch.

This is the sugar coma.

Yes, we all experience that,
don't we?

These african elephants
finding this one mango tree

Is really impressive
when you understand

That their home ranges
are massive.

Up to 9,000 square kilometers.

That's the equivalent of around
180 manhattans

Or the size of connecticut.

Now, you try finding
a mango tree in that.

Narrator:
How do these elephants know when
the mangos are ready to eat,

And how do they find
their way back

Across such a vast area
year after year?

One theory could
be visual signs.

Could they be using, perhaps,
landmarks

And specific geographical signs
that are helping them build up

A picture of the environment
to return back here?

Narrator: It's thought the
elephants have been dropping by

For over 25 years,

Long before the hotel
even existed.

So is it possible the herd are
using features in the landscape

To find their way back?

Narrator: In zambia,
wild elephants

Make an annual pilgrimage

To the mfuwe lodge
to feast on juicy, ripe mangos.

But how do they find them
in their vast home range?

One theory is they could be
relying on visual cues,

Landmarks along the route
to navigate by.

A lot of animals do rely
on visual cues

To get around different
locations and to find food.

Daly: Flying insects, such as
wasps, recognize landmarks,

Such as stones or fallen leaves,
before they leave their nest

So that they can navigate
their way back.

And it's thought that mammals
do this, too.

But remember that, in a dynamic,
changing landscape,

So you rely on visual cues
to try

And navigate your surroundings
to try and find your resources.

So I think that they are relying
on something else.

So, do they have some other
mammoth skill

That they might be relying on?

Isn't there a famous saying
about elephants?

Elephants never forget.

Narrator: Melissa schmitt has
been working with elephants

For the last five years.

Today, she's meeting up with
some old friends

In limpopo, south africa.

Schmitt: So, african elephants
have an incredible memory.

It's quite remarkable.

They can actually remember
life events,

Specific events in time.

They recognize individuals.

They could -- thank you --

They can recognize
other herd members.

They also have a really
remarkable memory

Of where resources are located
in a landscape.

And memory's very advantageous,

Especially in an environment
like an african savannah.

Narrator: And elephants
definitely need to be experts

At finding sources of food.

Galante: African elephants
need to consume

Up to 400 pounds
of food a day.

So they'll spend up to 18 hours
doing nothing

But looking for food.

Narrator: In the perilous
african landscape,

Foraging for this incredible
amount of food is no mean feat.

African savannahs are typically
characterized by two seasons --

A wet season
and a dry season.

During the dry season,
the grass is brown.

Many of the deciduous trees
have lost their leaves,

And water becomes
much more scarce.

And having knowledge
and memory of resources

That are longer lasting
would be incredibly advantageous

For elephants to know

So they can revisit
those resources.

Narrator: That means the bigger
the area they patrol,

The better the chance
at finding food.

And that's because even though
they are roaming larger areas,

They're able to remember exactly
where those resources are.

Whether it's a watering hole
or a mango tree.

Narrator: Amazing.

It's an elephant's ability
to mentally map

The location of vital resources

That guides them back here
each year.

But there's another twist
to this mango mystery.

Memory for elephants
is a really important tool,

But in this case,
memory can't explain

How the arrival of elephants

Coincides with
the fruit ripening.

And that's because
the time of year

When the fruit is ready
to eat changes year on year

Depending on rainfall
and climate.

Narrator: What?

The timing of the fruit's
ripening varies

From year to year?

So how do the elephants know
when it'll be at its ripest?

Daly: What am I missing here?

What is the elephant
in the room?

Schmitt: It's quite obvious that
you see first

About an elephant
is their trunk,

And their trunk
is incredibly interesting

Because you can actually think
of it more like a multi-tool.

Narrator: Most importantly,
they use it to smell.

And according to science,
they are rather good at it.

In 2014, it was discovered
that african elephants

Have the best sense
of smell of any mammal.

And when we think about
other mammals

That have a good sense of smell,
let's take dogs, for example.

They have 800 genes
responsible for smell.

The african elephant?

2,000 genes.

So we can see that, even from
a genetic point of view,

Smell is really important.

In fact, it's thought that
this super sense of smell

That elephants have can
help them avoid danger.

Narrator: A recent study shows
just how incredible

An elephant's ability
to smell really is.

For 27 years,

The african country of angola
was gripped by bitter civil war.

After that civil war,

The countryside was littered
with land mines.

It affected not only humans,
but also wildlife.

So it turns out that these
elephants were able

To detect the smell of the tnt
inside the land miles.

They associated that smell
with danger,

And so they avoided
those land mines.

Narrator: If elephants can quite
literally sniff out danger,

Can they also be using
their extraordinary noses

To work out when the mangos
inside the lodge are ripe?

Narrator:
In zambia, a herd of elephants
visits the same hotel each year

To feast on the garden's mangos.

It appears they rely on memory
to get there,

But this doesn't explain
how they time their arrival

To coincide
with the ripening of the fruit.

Scientists have discovered
that elephants

Have the strongest
sense of smell of any mammal.

Could this be how they know
the mangos are ready to eat,

Even if they are
many miles away?

Aryee: One of the other
important resources

That elephants need is water,

And they can use their sense
of smell to find it.

Daly: While water is odorless,

Elephants can smell
signs of water.

So chemicals, bacteria, algae,
and plant matter,

And as elephants
have such good noses,

They can actually smell this
water even if it's out of sight.

Schmitt:
Elephants are able to do this

Because they're able to maneuver
their trunk into the wind

And smell things
that are quite a distance away.

Narrator: This is the missing
piece of the puzzle.

When the elephants pick up
the scent wafting in the wind,

They know the mangos
are ready to eat,

Even if they are miles
from the hotel at the time.

Aryee: These elephants are using
their incredible sense of smell

And coupling that
with their incredible memory

To know exactly where to go
and when those mangos are ripe.

Narrator: These sweet-toothed
elephants have lucked out

With a mammoth memory
and superior snout,

Meaning it's mfuwe mangos
without a doubt.

This is proof that these animals
can really multi-tusk.

♪

Narrator: August 13, 1988.

The north atlantic ocean off
the coast of portland, maine.

A group of tourists
on a sightseeing trip

Are treated to
a spectacular sight.

-Look, look.
-Here comes another one.

Whoo!

It's a very interesting video
where you see a burst of bubbles

In a ring formation
come up to a surface.

Narrator:
The circle looks almost solid

Until it reaches the surface

And then disappears.

A few seconds later,
another one pops up.

A strange circle of bubbles

Suddenly appear
on the surface of the ocean.

What's causing that?

Narrator: Is there a clue to be
found beneath the ocean floor?

So when we see this giant bubble
coming to the surface,

One possibility is that this is
just a giant gas bubble

Maybe coming from
some deep-sea vent.

Narrator:
Hydrothermal vents occur

In volcanically active regions.

They spew out a constant stream
of superheated water and gas.

But gas bubbles
are typically spherical.

Could it really be possible
for a subsea volcano vent

To belch out giant,
circular bubble rings?

Narrator: Off the coast of
portland, maine,

Tourists observe
a mysterious bubble ring

Rising to the surface
of the ocean.

Is it possible that the cause
is underwater volcanic activity?

Well, some volcanos aboveground
do produce smoke rings,

And the same forces
that hold together a smoke ring

In the atmosphere
apply underwater.

Schreiber: Could it have been
a giant gas bubble

That erupted from the bottom
of the ocean,

Rising to the surface?

Most likely not because

You wouldn't get a perfect
circle if that happened.

Narrator: So, what is producing
these circular bubbles?

Well, soon after
the second ring surfaces,

There's another surprise.

So now there's a whale
in this story.

Hands up if you saw
that one coming.

But what is it doing?

Another possibility is that
the ring of bubbles

That we're seeing,
it's actually a bubble net

Or a bubble curtain that's being
made by certain whale species.

Narrator: Humpback whales
use bubble curtains

To hunt their prey.

The complex choreography
begins with whales

Diving below a school of fish.

They then swim in a spiral
towards the surface

While expelling air
from their blow holes.

The fish are too scared
to go through the bubbles,

So they stay in, and the whales
will get narrower and narrower

Until they're all corralled,

And they can actually go
and eat those fish.

Narrator: Were these tourists
lucky enough to see firsthand

One of nature's great
hunting techniques?

It could be that, sure,
but we don't think so

Because they're just --
it's too perfect a circle.

Nosal: If this were bubble nets,

We would probably expect
multiple bubbles

To be coming up
at different times

Because there's more than
one whale participating in this.

Narrator: If the whale in this
footage isn't hunting,

What other reason might it have
for blowing a giant bubble?

We know that dolphins will also
blow these sort of bubble rings,

But on a much smaller scale
just for fun.

We know that belugas
will do it, as well.

And so what we're seeing
with these larger whales

Is basically
a larger ring bubble.

They're probably doing
the same thing

That these dolphins
and belugas are doing.

It's learnt somehow to make
this perfect shape

Like blowing smoke rings

That rises
to the surface of the ocean.

It's clearly playing around
and having fun.

Narrator: Like dolphins,
whales are well-known

For their love
of social behavior.

And it appears this one
has also mastered

The science of fluid mechanics.

These divers show exactly
how it works.

Water pressure increase with
depth, so as the bubble rises,

The pressure decreases,
allowing it to expand.

The deeper the whale
goes to blow,

The bigger the bubble can grow.

Nosal: And it turns out that
the humpback whale

Blowing these bubbles
likes showing off.

He blows bubbles right next
to the tourist boats

That are coming to see him.

Narrator: The crew of
the whale-watching ship

Who captured this footage
made 17,000 trips over 16 years.

Good job they hit record
this time.

-- Captions by vitac --
www.Vitac.Com

Captions paid for by
discovery communications