Nature's Strangest Mysteries: Solved (2019–…): Season 1, Episode 16 - Scorpion Night Lights - full transcript

Narrator: Ever wondered why
an apex predator

Would let this guy escape?

So this is
very bizarre behavior.

Narrator: What could cause
this ominous, dark mass?

So, it looks as though
there's this apocalyptic cloud.

Narrator: And why scorpions
can light up

Like a las vegas nightclub?

So this is just a mad scene.

♪

Narrator: Nature
is awe-inspiring.

But sometimes it just
doesn't make sense.



Man: I have never seen
anything like this.

Narrator: Our team of experts investigate
the weirdest animal behavior...

That's amazing.

...And the most
unexpected events...

What is causing that?

...Ever caught on camera.

Woman: My god!

These are...

Captions paid for by
discovery communications

Narrator:
Londolozi, south africa.

A safari guide captures
a dramatic scene.

A civet... a small,
cat-like mammal...

Cowers in the middle
of a puddle.

Why is it so scared?



Because it's being eyeballed
by an enormous leopard.

♪

It's a case of "wrong time,
wrong place"

For this normally
nocturnal critter.

The question is,
what will it do?

♪

So, it's a really tense
bit of footage.

Narrator: The leopard slowly
circles the water.

But then...

[ whimsical music plays ]

...Flops down to sleep.

So, why hasn't she launched
an attack?

♪

Narrator: Is she the laziest
leopard in the world?

Lunch is right there.

There's no chance that that
leopard can't see the civet.

The civet's stopped moving,
therefore is invisible.

We're not talking about
"jurassic park" dinosaurs here.

Schreiber:
These are nocturnal hunters.

They have incredible eyesight,
they have incredible smell.

There is no way that she has
just walked past the puddle

And not noticed
a living civet inside of it.

[ Beeps ]

Narrator: So, what's going on?

♪

Maybe this leopard does not
like hunting in water.

Burke: This leopard looks really
reluctant to get its paws wet,

And, of course,
cats are quite famous

For not really liking the water.

Narrator:
But that's domestic cats.

[ Shrieks ]
big cats,

Like this jaguar,
are a bit different.

I've seen jaguar hunting
in the water.

I've seen jaguar hunting caiman,
which is a kind of,

You know, crocodile, basically.

♪

Tigers are famous
for it as well.

You know, they'll quite happily
swim and wallow.

♪

Narrator: And certain leopards
actively hunt fish for dinner.

In botswana,
there's a population

In an area called savuti
where the leopards

Have really specialized
in hunting in the water.

They actually hunt catfish.

Narrator: So a puddle this size
wouldn't stop a leopard.

I think if it wanted that civet,
it would have it.

I think there's other things
at play here.

Narrator: Could there be a clue
in the civet's stance?

He's standing hair on end
to look as big as possible.

♪

[ Beeps ]

Has acting tough saved him?

♪

When a predator's
coming after you,

Feistiness can be
a secret weapon...

Like these river otters
that successfully ganged up

To see off a lurking crocodile.

But the crocodile
was outnumbered.

So is there more going on here

Than just a civet
standing up for itself?

[ Beeps ]

Could it be that the civet
just isn't that appetizing?

Civets are know for
one thing in particular...

Civets are famously
smelly animals.

They have massive anal glands,

And they produce this sort of
oily, musky secretion,

Which is not particularly nice.

So you've got to be
pretty hungry,

I'd imagine, to be a leopard
to bother with a civet.

They've probably encountered
a civet in the past,

And you don't really want
your dinner

Scratching your face
as you're eating it.

Narrator: Is this civet just not
worth the effort?

As the footage unfolds,

Another leopard
enters the picture.

♪

This male comes on the scene.

We start to realize that maybe
she's distracted

By something else.

Narrator: Are they more
interested in each other

Than in food?

Now, leopards are solitary
animals.

They don't spend a lot
of time together.

Narrator: Even when hunting,
they go it alone.

♪

But when it's time for business,

A pair will stick together
for days

And mate up to
100 times in 24 hours.

[ laughs ]

♪

Burke: So as this male
joins the female,

They clearly have
something else on their mind.

Narrator: Something else,
but not necessarily mating.

♪

Burke: There's a lot of tension.
They have a little scuffle.

[ Grunting ]

Narrator: And they bolt
straight up the marula tree.

[ Growling continues ]

Another clue, right there
in the footage,

Reveals what
they're fighting over

And why they've
ignored the civet.

This video clip turns from
a curious bit of behavior,

Or a curious lack of behavior,

To when the second
leopard turns up.

And then as it climbs up that
marula tree in the background...

[ growling ]

...At the top of it
is probably a key part

Of this whole story.

Narrator: The civet would just
be a starter anyway.

It seems the leopards
have already stashed

Their main course
up in the tree.

Baker: The remains of a kudu carcass
...this is a massive antelope.

So this leopard isn't
short of food.

So why eat a civet when you got
a belly fully of prime venison?

Burke: So that's the reason
why the civet isn't really

That interesting
to these leopards...

Because they already
have something to eat.

Narrator:
Keeping a treetop pantry

Is standard practice
for leopards.

Baker: Why bother drag a kudu
carcass to the top of a tree

Is that this is africa.

It's full of other animals
that will steal your carcass.

Hyenas in particular will
easily steal from a leopard,

So they just want to get that up

And out of the way
of animals that can't climb.

♪

[ Birds and insects chirping ]

♪

Narrator: Phoenix, arizona,
summer 2018.

As night falls,
a pest-control team

Are sweeping homes and gardens.

They've been called in
by worried homeowners

To look for venomous scorpions.

You know, the most we've ever
caught in a home is about 280.

Our average is 12 per sweep.

Gaffin:
How dangerous are scorpions?

Well, the scorpions
from south arizona,

The arizona bark scorpion,
are pretty dangerous.

Globally, I think it's about

1.2 million stings per year
from scorpions.

Narrator:
Why hunt them at night?

Well, during the day they're
camouflaged and hard to spot.

But at night under black light,
also known as u.V.,

They give themselves away.

They glow.
Holland: Here we go.

These are arizona bark
scorpions,

Which are the most venomous
here in the united states.

♪

They have little hooks
on the bottom of their feet

That will grip onto texture,

Much like velcro hooks
into the loops,

Which is how they get
on people's walls

And in people's houses.

You can see that they glow
rather well

Under this ultraviolet light.

♪

Daly: There are over 2,000 known
species of scorpions,

Almost all of which are thought
to glow under u.V. Light.

♪

Greive: One of the great, vexing
questions for entomologists

Is, "why do scorpions glow
under ultraviolet light?"

Narrator: It's puzzled
scientists for decades.

To try and figure out why,
first we need to understand how.

Scorpions have this wicked trick

Where they take light
in at one wavelength,

And then put it out
at a different wavelength.

It's called fluorescence.

Gaffin: In their outer layer
of their skin,

There's a couple of chemicals,

And when ultraviolet light
stimulates these molecules,

They emit the fluorescence
that we see.

If you want to see fluorescence
in a scorpion,

It has to be ultraviolet light.

Greive: The key to a scorpion's
ability to glow under ultraviolet light

Is contained in this very hard
coating over the entire animal.

The actual chemical that enables
scorpions to glow,

It's called carboline,

And this has been true for
millions and millions of years.

Scorpions have been around
for a very long time.

In fact, there are
fossil scorpions

That are, like, this big.

Narrator: The carboline
in scorpion skin

Is a u.V.-Absorbing chemical.

In other animals, similar
chemicals act as sunscreen.

[ Insects chirping ]

[ Beeps ]

Could the same be true
for scorpions?

♪

Now, this would make sense,

Because way back
in evolutionary history

Scorpions may well have been
active during the day.

Narrator: So it's possible that
the carboline

That made
scorpion ancestors glow

Also acted
as prehistoric sunscreen.

Greive:
So could it be performing

That same function
for scorpions today?

Narrator: Maybe, apart from one
little hitch.

[ Insects chirping ]

[ Insects chirping ]

Narrator: In phoenix, arizona,
and, in fact, across the world,

Scorpions give up
their hiding places

By glowing under u.V. Light.

The chemical that made
ancient scorpion ancestors glow

Probably acted
as a form of sunscreen.

Is that why scorpions
glow today?

Sounds plausible, apart
from one small detail.

Today's animals are much smaller

And are almost
exclusively nocturnal.

[ Insects chirping ]

Narrator: Scorpions are most
active just after sunset,

So have no need for sunblock.

Burke: And it wouldn't
make sense for them

To keep producing a chemical
in their exoskeleton

That is no longer needed.

It just wouldn't make
any anagenetic sense,

So I don't think
that's the answer.

Narrator: If the chemical
is not acting as sunblock,

What is it for?

[ Beeps ]

Could it be the scorpions glow

To send each
other messages instead?

Are scorpions using this
glowing ability

To communicate
with other scorpions,

Either to define territories
or to repel rivals?

Daly: This isn't
completely unlikely.

Fluorescence has been used
to communicate

In other species, too.

A study was done on the skulls
of chameleons

Where they have
these florescent patterns,

Which can help other chameleons

Identify one another
in a dark environment.

Narrator: It's not out of the
question that a scorpion's glow

Could be for communication,
just like the chameleon's.

♪

So what about glowing
as a lonely hearts ad?

I wouldn't rule this one out.

I think there is a chance
that perhaps males

Might be detecting
females from a distance.

♪

Narrator: A faintly glowing
female could be like a beacon

To a male scorpion.

That's a "maybe" then
to passionate scorpions

Glowing for love.

Professor douglas gaffin
has been studying scorpions

For 25 years.

He thinks their glow
could be multipurpose,

But that it's most likely
for keeping them save.

Perhaps they are using the light
as detected through their body

To seek out places
to hide for protection.

[ Beeps ]

Narrator: Hang on.
For protection?

These are scorpions
we're talking about...

Fierce, tail-bending
stinger demons.

They've got some amazing
seismic detectors

On each of the eight legs.

♪

They actually detect vibrations
of the crickets as they walk by.

Riskin:
They've got pincers,

But those are just sort of
for keeping you at bay.

The real business end
is at the back.

♪

If the scorpion
feels threatened,

It can bring its tail down

And whack you
and inject venom very quickly.

♪

Narrator: You have to be brave
to face down a scorpion.

But some animals,
like this bat-eared fox,

Will take on the challenge.

You see, scorpions
are quite exposed

When they're out there
on the sand.

There are predators
of scorpions.

♪

Narrator: Scorpions are packed to
the rafters with fancy features,

But they have an achilles' heel.

Scorpions don't have
very good eyesight at all,

So when they're running to hide,
they need another mechanism

To help them know whether
they're hiding effectively.

Narrator: Could their incredible glow
be a tool to help them stay alive?

♪

[ Insects chirping ]

[ Insects chirping ]

♪

Narrator: In phoenix, arizona,

We're unraveling the secrets

Of why scorpions glow
under ultraviolet light.

Could it be for protection?

Scorpion vision is mostly tuned
to daytime colors... green,

Which is fine
when the sun is up,

But at night, they need
another way to detect

Whether they're hidden properly.

♪

This is where we run
our experiments

To learn more about
scorpions' reaction to light.

Narrator: A team of scorpion scientists
at the university of oklahoma

Decided to find out
how they manage it.

Taylor: We'll take it out,
and we put them in these little arenas.

Narrator:
These arenas will be floodlit

Under the lights
of a scorpion disco.

And within these cylinders,
we have small lights...

Either green lights
or u.V. Lights.

We put this on top.

Within the box, we have
a small infrared camera

That videotapes them from below.

Gaffin: So in our early
experiments, we found

That scorpions appear
to be sort of agitated

Under both green
and u.V. Light.

They kind of run
in little spurts.

♪

Narrator: Shining both these
lights on a scorpion makes it run,

Because it senses the light

And that it's exposed
and therefore vulnerable.

We decided to look to see
if the eyes were responsible

Or if different parts
of the body

Were responsible
for this behavior.

So we made these little
tiny goggles out of foil

To cover their eyes.

♪

Narrator: The experiment found
that with tiny goggles

Blocking their eyes,

The scorpions didn't feel
the need to run for cover

Under green light.

They couldn't see it,

So didn't sense
that they were out in the open.

But they still ran when
ultraviolet light

Was shone on them.

Gaffin:
When we cover the eyes,

We still see some behavior
under ultraviolet light.

So we had fairly
clear difference in behavior,

Suggesting that perhaps
there was some sort of detection

Of light
beyond the eyes themselves.

Narrator: So it seems that
even when blindfolded,

Somehow they were able to
still see the u.V.

With other parts of their body.

We don't know exactly how
they know they're glowing,

But it's possible
that signals from

The u.V. Light-induced glow

Could pass through nerves
to their brain

To tell them light
is falling on them.

The extraordinary conclusion
from doug gaffin's work

Is in effect,

A scorpion is omnispective,
all-seeing.

♪

Burke: Having this way
of sensing u.V. Light

Across the whole body

Is a really clever way
of making sure

That when they're hiding, all of
them is actually concealed

And they haven't left any part
of their body out and exposed.

Narrator: Why is sensing u.V.
In particular important?

Because just after sunset
when a scorpion is most active,

The proportion of u.V. Light
is at its highest.

So if a scorpion were to scurry
when startled

And just any part of its body

Were under a little twig
or a leaf,

It could reflexly move
towards the shade

And maybe have a measure
of protection.

Narrator: It looks like
scorpions' attention-grabbing

Fancy fluorescence
is actually to help them hide,

And maybe to help them
see each other, too.

[ Insects chirping ]

♪

Narrator: April 2014.

In northern iceland,
a couple on a boat trip

Film a dense cloud hanging over
the surface of a lake.

There's this apocalyptic cloud

Rolling across this lake
in iceland.

This really thick, dense,
dark cloud

Hanging very, very low
over the water.

Narrator:
What is causing it?

[ Volcanic rumbling ]

Iceland is known as
the "land of fire and ice."

It's notorious for its ice,
but when it comes to its fire,

That's referring
to its volcanic activity.

[ Volcanic rumbling ]

A thought was, "well,
could this be a cloud"

From a nearby volcano,
an ash cloud or something?"

Narrator: With over 30
active volcano systems,

Iceland has history

With belching out
apocalyptic ash clouds.

But no volcanic activity
had been recorded at that time.

♪

It became obvious
this was not smoke at all.

Narrator: Because this
ominous cloud is alive.

♪

[ Insects chirping ]

[ Insects chirping ]

♪

Narrator: In iceland,
an apocalyptic lake cloud

Hangs in clear, blue sky.

At first, it looked like
volcanic ash or smoke

Billowing across the surface.

Only when you get a much
closer look

At actually what's going on,

You start to see
individual organisms.

[ Fluttering ]

♪

Of course, they are midges...

Thousands and thousands
of midges.

Narrator: Midges
are tiny two-winged flies.

And there aren't just
thousands... there are millions.

When a million midges
crash your boat trip,

You have to get creative
with headgear.

[ Fluttering ]

Midges sure know how
to wreck a boat trip.

But why do they swarm like this?
[ buzzing ]

[ Beeps ]

♪

Daly: Midges all hatch
at the same time.

That's what creates
these huge clouds,

And when they do form
these huge clouds,

It's really all about mating.

Narrator:
Midges hang out by lakes

Because they need the water.

They lay their eggs in it,

And spend the first part
of their life

Living as larvae
under the surface.

Burke: Many species have
this kind of life cycle.

They might spend years
as their larval stage underwater

And only a few days or sometimes
even a few hours as adults,

And it's that brief
little window

Where they have
an opportunity to mate.

Narrator: Adult flying midges
have no mouth parts and don't eat,

So they have just a few days
to do the deed

And lay their eggs
before they die

So the cycle can begin again.

And in lake myvatn,

Which means "midge lake"
in icelandic,

Huge clouds of mating midges

Will appear every few weeks
during the summer months.

Make sure you have
a bucket handy.

[ Camera shutter clicks ]

[ Insects chirping ]