Central American Jungle The Dark: Nature's Nighttime World

As night creeps across the planet

and our familiar, daytime world is plunged into darkness,

strange creatures are beginning to stir.

This is when most animals are active.

But the drama of their nocturnal lives is hidden from our eyes.

These are specialised beasts...

all adapted for the dark.

It's is a world we know almost nothing about.

Now a team armed with specialist cameras

is travelling to the remotest corners

of Central and South America.

Unbelievable.

To uncover the secret lives of animals after dark.

(Oh, wow.)

Look at that.

It is a journey into the unknown.

This one will kill you.

-Holy

-BLEEP.

-What is that?

I shouldn't really be out here alone.

South and Central America

has some of the richest habitats on Earth.

From tropical jungles in the north to frozen mountains in the south.

Over six months, a team of biologists and filmmakers

will find and film nocturnal creatures here.

Why do so many animals come out at night?

How can they operate in total darkness?

The expedition will survey the continent from top to bottom.

But their journey starts here, in Central America.

Dr George McGavin is heading up the team.

I would imagine very few people have been out after dark

in this part of the world.

So I'm not entirely sure what I'll find there.

They've packed over a ton of specialist equipment

for filming at night.

Well, that is not quite all of it, actually.

There's a little bit more to come.

It's unbelievable how much stuff there is.

But everything will be used, every bit of it will be used.

George is a former Oxford University biologist

and world-renowned insect expert.

He will investigate how miniature predators hunt at night.

What I'm particularly interested in is specialist hunters

who are active after dark,

who have an amazing range of techniques to catch their prey.

Bryson Voirin is an expert in larger nocturnal creatures.

He will discover how they function in the pitch black.

Central America is full of big animals and I'm here to see

which of them are out at night-time and to see what they're up to.

The jungle here is teeming with animals, most of them nocturnal.

The team will track them down

to reveal the secrets of survival in the dark.

Base camp is a remote research station

in the heart of the rainforest.

-Hammock or tent, Bryson?

-Ooh, I might take a hammock.

-Really?

How about you? Yeah, above the ground is better for me.

-I can't, can't sleep in those things.

-Really?

-Yeah.

To work at night the whole team will have to turn their body clocks

upside down and sleep during the heat of the day.

I'm a little bit concerned because it's so hot right now,

I don't know how I could ever fall asleep being covered in sweat.

I've already drunk two litres of water in just the past 20 minutes.

So it's going to be challenge trying to get enough sleep.

Before the first nightfall,

the main expedition tries to rest or prepare equipment.

Another member of the team has headed north to stake out

a remote stretch of coastline.

Justine Evans is the world's leading night-time camera specialist.

She's here to investigate sightings of jaguars.

Park rangers have captured images of a jaguar from remote cameras

near the beach and have seen their tracks in the sand.

These elusive big cats are active under the cover of darkness,

when their keen senses give them the edge over their prey.

Jaguars hardly ever leave the thick jungle.

This is a rare opportunity to observe their natural behaviour

and discover why they visit this beach at night.

Justine has built a hide four metres high.

It'll keep her hidden and her scent off the ground.

I don't want to get my hopes up too much

cos we might spend two weeks getting nothing,

but I'm excited about the idea of actually seeing one standing there.

That would just, that would be a real dream.

For now, Justine must settle in and wait.

As daylight fades over the jungle,

the rest of the team head out for their first night of exploration.

There's something up there.

Oh, spider monkeys. Yeah, spider monkeys just up on top there.

They're just using the last half hour of sunlight

just to get extra food.

And then that'll be it and the evening shift takes over.

We're trying to unlock the secrets of the night

and find out what things really do

at the time when we are never up, we're usually asleep.

The team will use two specialist night vision technologies.

Thermal imaging cameras detect heat,

making warm-blooded animals easy to spot in the darkness.

And infrared cameras record a spectrum of light

invisible to animal eyes.

The team will be able to follow nocturnal creatures

without disturbing them.

And see how they survive in a world

where, without technology, humans are helpless.

Close to base camp, Bryson and a local boatman are preparing

to head up a forest river.

My boat is about as unstable as they get.

It's basically a canoe packed full of all my equipment

with an engine on the back.

So if the slightest thing bumps into us or there's too many waves,

it'll tip right over, I'll go in the water.

Bryson is searching for large, nocturnal animals.

Using the river, he can cover more ground

and explore deep into heart of the forest.

Scanning the banks with a portable thermal imaging camera,

he soon picks up a massive heat source.

(Oh, it's back there.)

(What is that?)

I can just make out its mouth.

And I think it's a tapir. It has a long nose.

Tapirs look sort of like a funny-looking elephant.

See if I can get closer.

Tapirs are the largest forest animal in Central America.

They're not strictly nocturnal,

but they prefer to forage for food in the dark, when it's cooler.

Tapirs are actually really well-suited for night-time activity.

They don't see very well at night-time,

but they hear really well.

They've got these big, goofy ears that can move around,

that can hear really well.

Their hearing helps detect predators.

And their acute sense of smell helps them identify 100 types of plant.

Now, the reason they eat so many different types of plants is

because a lot of the leaves in the rainforest are actually toxic

and so, in order to have a balanced diet,

they eat a bunch of different things,

so they don't get too much of one toxin and they can process it.

Because of their size, tapirs have few natural predators,

but humans hunt them for their meat.

They're very, very shy usually.

There must be absolutely no poaching in this forest

cos he's not afraid of me at all.

Oh, my God.

This thing is walking right towards me.

I've never been as close to such a big animal.

Woah.

Oh, my God, my heart is beating so fast.

I've worked in Central America for over ten years.

I've never seen a tapir, I've always wanted to.

It's incredible.

Bryson is blind without his camera.

But the tapir is completely at home in the dark.

When sight fails, other senses compensate.

Back near base camp, George is looking for miniature predators

that have evolved to hunt in the dark.

Spiders.

Just every inch of this forest is covered in spider web.

If you took all the spider thread in this forest alone,

it would wrap the Earth up, probably, about five times.

It's just... There's so much of it.

Spinning a web leaves spiders exposed

to larger night-time predators.

So some have evolved to remain hidden and still catch prey.

Now, ideal habitat here

for a rather specialised nocturnal hunter.

Trouble is, they're very hard to see.

Ooh, there's a whip spider in fact, look at that.

That's not what I'm after.

That is a nocturnal hunter, but the one I'm after is rather sneaky.

George is searching for the ultimate ambush hunter.

Right, here's one. Right.

Now, that is a trapdoor spider.

Now, these spiders are amazing.

They live permanently inside a silk-lined tube.

And they just make a little lid out of debris and soil and silk.

And it fits absolutely perfectly onto that hole.

Hidden behind the trap door,

the spider detects its prey through ultra sensitive hairs on its legs.

When it feels vibration,

it springs the trap.

So if I get a stick and I just lever it up,

you can see, yeah, in there. Can you see it?

Now, he's in there, OK?

So he's going to wait until an insect crawls past.

All we've got to now is to sit here and wait.

These spiders remain safely hidden day and night.

They only risk emerging for a split second

under the cover of darkness

to snatch their victim.

Oh, here's a cricket, look, look. A tree cricket, a very small one.

It's just beneath the lip.

It's preening now.

It's just millimetres from the edge of the lid and it's stopped

and it's preening its antennae and leg.

Now, the lid's moved, just a fraction,

so the spider is aware it's there.

(Oh, it's close.)

Yes! Got it. Look at that.

Didn't you see that?

That was so quick.

This is just one of the ingenious hunting strategies

spiders have evolved.

George heads deeper into the forest in search of more.

On the coast, Justine has found no sign of jaguars.

But her cameras have detected another animal

using the cover of darkness to slip onto the beach.

Wow.

That's an amazing sight.

There's a turtle coming out of the sea.

This is peak nesting season now,

for the next three months.

Female green turtles time their beach landings

for the darkest nights.

They lay up to 200 eggs in the sand.

Hidden by the night, the eggs are safe

from daytime predators, like the black vulture.

They will incubate in the warm sand for two months.

Eggs laid by earlier females are already hatching.

(Oh, some freshly hatched turtles.)

(Just see these little, white creatures all just bubbling away.)

It's close to dawn.

Vultures are leaving their roosts and coming onto the beach.

Turtles hatch in the dark to avoid predators.

This group is cutting it fine.

The vultures are out and they're passing in front of them,

but it's dark, the vultures haven't noticed them,

so it does clearly show the advantage of emerging at night

versus during the day.

If they were doing this in daylight, they'd be mincemeat.

Those vultures would be on to them like a shot.

Fortunately for the turtles, very few birds have good night vision.

(I have a lot of respect for these little guys.)

(I think they might make it to the sea.)

The dawn chorus marks the start of the day shift.

Animals that have been active all night find a safe place to rest.

Most mammals, reptiles and birds have to sleep.

Some scientists think it is vital to regenerate muscle

and tissue in the body and chemicals in the brain.

Humans can go longer without food than they can without sleep.

Upriver, Bryson is burning the candle at both ends.

He's setting up motion sensitive cameras.

I've only got one set of eyes,

but with these I can have hundreds of eyes, all over the forest.

The camera traps will reveal

what other large animals live in this forest

and how they behave at night.

After failing to see a jaguar last night,

Justine's searching a few miles further down the beach

for any signs they might have left.

Look at this.

This is what I've been looking for.

This is jaguar tracks, definitely.

Look at the size of them.

Big tracks, bigger than my hand.

Heading straight south, down the middle of the beach.

This is a mature individual and it's definitely jaguar.

Without this evidence,

I didn't know for sure that jaguar were on the beach, but now I know.

100 metres on, Justine makes a gruesome discovery.

Wow.

A half-eaten turtle.

It's all been spread by vultures, most likely, all these bits.

But what killed it is another thing altogether.

Something's gone through that shell

and that's something really significant,

something like a big cat that can bite through.

And the head has been virtually severed.

And again, I mean, that takes a lot of effort.

That's not just a bird pecking away or a crab nibbling,

this is something big.

So, I mean, we might have our first jaguar kill here.

Poor girl, though.

The carcass is proof that jaguars are visiting this beach at night

to hunt nesting turtles.

Justine heads back to the tower. She knows she's in the right place.

Now she has to wait.

Before night falls, Bryson is pushing further upriver,

towards a swamp where he hopes to find large, nocturnal predators.

But progress is slow.

We've been working, basically, all day, just trying to get

a few miles of river right now and we still have a long way to go.

Fallen trees block the way.

And it's choked with vegetation.

Well, there's another dead tree in the way.

Oh, something just dove right in front of me.

SPEAKS IN SPANISH

There's something diving right in front of me.

Well, the sound, when I'm hitting the branch with my machete,

makes a really deep pulsing sound

that actually attracts crocodiles a lot of times.

THUMP THUMP

I'm going to try and get this done.

Woo.

It's the hardest boat journey I've ever made.

Few people have made it this far upriver.

It's a unique opportunity for Bryson to find out

what emerges in the heart of this jungle after dark.

700 miles north of base camp is one final member of the team.

Wildlife cameraman Gordon Buchanan.

He's aiming to learn more about the jungle canopy.

By day, primates like the howler monkey gorge on fruits and leaves.

What animals exploit this rich food source at night?

How do they function in the dark?

Gordon has chosen a unique vantage point.

Oh, my word, look at this.

Gosh.

Now, that is impressive.

I've seen lots of impressive things in the rainforest,

but nothing, nothing like this.

These are the remains of an ancient Mayan city.

This temple was once a site of worship and human sacrifice.

These ruins have left openings deep in the forest.

The best thing about these temple clearings is that the forest is

so dense that you can't actually see what's right in front of you,

but here you can actually see

this whole tree line.

So you're covering maybe 200-300 metres of forest from one position.

This site will make it easier to spot secretive canopy dwellers

and see how they've adapted to move about the trees in the pitch black.

About 20 minutes from now, the sun's going to disappear

and that's when things start changing.

Light level drops, the temperature drops

and it's the start of a different world.

This is really the start of the dark.

Gordon's first task is to find fruiting trees.

During the day, monkeys, parrots and these toucans will feast on fruit,

but, at night, they hide from predators and sleep.

Now is the chance for night-time canopy specialists

to come in and feed.

It's not long before Gordon's strategy pays off

and he spots movement above.

Gordon's infrared camera uses light which is invisible to animal eyes,

enabling him to take a closer look.

OK, there is something climbing up this vine.

Right, look.

That is a possum.

Now, possums are just one of those peculiar animals,

quite unlike the kind of animals you expect to bump into during the day.

Possums are nocturnal.

During the day they sleep in hollow trees or holes in the ground.

And it is a bit of hotchpotch of different animals really.

Look at those ears.

It's got the ears of a bat, kind of whiskers of a cat,

this kind of long snout.

Maybe not the most attractive looking thing,

but I suppose it doesn't really matter what you look like

when it's dark.

Possums have evolved a suite of super senses

that let them function at night.

They don't rely on their eyesight, which is relatively poor.

They find food by smell.

Their long, tactile whiskers help them feel their way in the dark.

Their hearing helps them detect predators.

That's vital when they leave the safety of the trees

to forage for insects on the ground.

Ooh, he's got something there, he's found something.

I can't quite see what it is.

Something small.

It's a very rich place for a possum. Literally comes down the tree

and finds something to eat straight away.

Possums will eat just about anything.

Rodents, fruit and snakes, lizards.

It's a generalist rather than a specialist.

Possums have a clever trick to avoid being eaten.

They've got a very interesting, unusual way of deterring predators

and that is playing possum, pretending that they're dead.

And they go into this stupefied state.

They lie on their side with their tongue hanging out,

their eyes open and they will stay like that for 40 minutes.

And the belief is they'll give off a smell of rotting meat

that's going to deter quite a lot of predators.

The possum is a good start, but there are animals here

that spend their whole lives in the trees at night.

To find them, Gordon must move on.

Near base camp, George is still searching

for his ultimate mini predator.

He has a particular animal in mind.

The net-casting spider.

During the day they hide,

but at night they use a unique hunting strategy.

Ooh, hang on an minute.

Oh, my God. It's the first time I've seen this.

What it does, is it spins a framework of silk

which holds itself in place.

It then spins with special silk, which is this blue silk

which isn't the same as the ordinary silk it makes.

And that blue silk is very stretchy.

And then, when the prey walks past underneath,

the huge eyes on the back row of the head see it.

In a fraction of a second, the front legs, the four front legs

stretch open the web as wide as it can

and throw it over the prey.

And it scoops it up into the web.

And it happens in such a fast time.

If you only had your eyesight, you would hardly see anything, a blur.

It would just be a blur.

And what would be great is to get this filmed in super slow-mo.

It would just be amazing.

Like most spiders, net-casters have eight eyes.

But one pair is huge.

Biologists think these are particularly sensitive,

letting the spider target prey in the dark.

To examine their incredible hunting behaviour for himself,

George has called in one of the camera crew, Sophie Darlington.

So where do you think? I'm just trying... I don't want to...

I can see these scaffoldings are coming down.

Right, he's going to catch something

that's going to pass beneath there.

Sophie sets up a high speed camera

that will slow down the action 40 times.

This behaviour has rarely been seen in the wild.

Filming it may take all night.

Rather than wait, George heads off into the forest

in search of more night-time specialists.

Oh, look. Look, look, look.

It's a headlight beetle.

Look at that. Is that not the weirdest thing ever?

Now, on the back of the thorax,

there's these two little, green-glowing organs,

which is produced by an enzyme.

Headlight beetles only come out at night.

Scientists think they use their lights to attract a mate.

On the underside, they've got an orange light as well,

which they glow when they fly.

Orange light.

And we're good to go.

Ha! Ha-ha-ha.

It's fantastic. Ha-ha-ha.

It's this bright light. Every time. Look. Orange light.

Prepare for take off. Ha-ha-ha.

Now, it was said by the early explorers

that you could actually read a book

by the glow of these particular insects.

If we switch off all our headlights and everything,

and just go to complete darkness, you'll see how eerily green they are.

Just beautiful.

By generating their own light,

these beetles have evolved an ingenious way

to communicate in the dark.

George returns to Sophie at the net-casting spider stakeout.

OK.

For six hours, no insects have walked into its trap.

This is something I've always wanted to see.

To have a chance of seeing it first-hand in the jungle

is just worth everything.

OK, here we go.

What is it?

(A tiny cricket.)

Ah!

Oh, that is just fantastic.

-Sophie, you are a genius, well done, absolutely.

-I don't yet.

-Can I check the shot?

-Look at it. Look, oh!

Only when the footage has been slowed down,

will they see if Sophie captured the kill.

So she hasn't now.

-OK.

-You ready?

-Yeah.

Then the antennules, it's just...

it's just touched that wire. There.

Orientates.

Opens the net.

Oh-ho!

-Ha-ha-ha.

-God, that's fantastic.

That is absolutely fantastic.

So it's not just the eyesight,

the antennae of the cricket touched one of the wires.

-It was a trigger.

-Yeah.

George can see, for the first time,

that net-casting spiders are highly sophisticated.

They use multiple senses to catch prey in the dark.

But I've never seen it with my own eyes...

-That was awesome.

-..until now.

She's a superb creature.

Bryson has followed the river inland towards a swamp.

There's still no sign of the large predators he's been looking for.

There's something swimming right around the boat.

Woah. Right, coming up.

Ooh, what's that?

What is that?

-Holy

-BLEEP.

Get my camera out.

Now, unfortunately, this camera needs light to work,

so I've got to use my flashlight to illuminate it.

And make sure it's on. OK.

All right.

Woah. There he is, there he is. Woah.

Woah, it's huge.

Wow.

There's a bull shark. Look at that.

Bull sharks have evolved to survive in fresh water.

It lets them hunt in the middle of the forest where prey is abundant.

Ready? It's coming right in.

Woah, woah, woah.

Jeez, you see that?

That's exactly how bull sharks hunt.

They come in and right before they're going to go in for the kill,

they bump whatever it is they want to eat.

And that helps them see what it is.

Bull sharks can hunt 24 hours a day.

They have acute senses tuned to catching prey in murky rivers.

So hunting at night is no problem.

It's got a really good sense of smell.

Sharks can smell blood in one part of a million in the water.

They can also sense electric charges.

So if a fish is swimming around, they can sense its electric field.

And they also have a really cool thing called a lateral line,

which is basically a really sensitive patch of skin

up and down their sides,

and it can detect any sort of motion around them.

So they can actually feel a fish swimming many feet from them.

It's kind of like if a big truck drives past you

and blasts you with some wind.

That's what sharks can feel when they're swimming around, hunting.

These bull sharks will feed on fish, baby crocodiles and river turtles.

They can even take tapirs as they swim the river.

Wow! That was amazing.

Seeing sharks in a freshwater river at night-time.

Ha! That's a first for me!

As the team searches for nocturnal animals

they must work right through the night.

It's an unnatural time for humans to be awake.

The punishing schedule is starting to take its toll.

On the beach, Justine is three sleepless nights into her stakeout.

Everything in my brain is telling my body to sleep.

To film jaguars in the dark, she must stay awake.

It's going to be worth it.

It's going to be worth it.

I keep telling myself that.

Something will happen. In the end.

There'll be a big, bright shape of a jaguar

right in the middle of the screen.

And then I'll be awake. That's for sure.

-SHE WHISPERS

-What is that?

No, that is something.

That...

..yes, yes, yes!

That's a jaguar!

That is a jaguar!

I don't believe it!

Whoa! Coming right out!

Yes!

It's coming right out to the beach.

Seeing a jaguar out in the open is unbelievably rare.

This is one of the first opportunities

to observe their behaviour at night.

Whoa!

This is the closest I've ever been to a wild jaguar.

There's a turtle right in front of him.

Is he going to get it?

Just walked straight past it!

Turtles are easy pickings on this beach.

But this big male is not in hunting mode.

He is interested in a smell on the sand.

Scent is an important way to communicate in the dark.

Jaguars have glands that they rub on the ground and on trees.

This marks their territories.

Just starting to see all sorts of bits of behaviour happening

which I didn't expect to witness.

Some people said to me, "You'll never film a jaguar.

"Not unless you use a remote camera."

But here I am,

with a jaguar not 20 metres away.

There's another one!

There's two! There's two! I don't believe it!

Two!

This is magical!

This is more than I ever imagined would happen!

It looks like a male and female.

Seeing them together is almost unheard of.

Jaguars are normally solitary and highly territorial.

They only meet up to mate.

Justine is seeing the intimate moment

when these two have come together to breed.

Wonderful experience.

We're finally able to witness their night-time behaviour

in a way that's not been possible before.

At dawn, the night shift draws to a close

and the beach becomes a more familiar place.

The last turtle hatchlings make a dash for the sea.

In the forest, Bryson has returned to check his camera traps.

They have been out for several nights.

He's hoping they've captured some of the large animals

that roam the forest after dark.

Any animals that walked in front of here will be videoed.

So hopefully there's some good videos on there.

A puma!

Wow! I knew there were pumas out here.

Pumas are mainly nocturnal.

During the day, they'll kind of rest because it's so hot,

but at night-time, they come out and they hunt.

Oh, my God! That's beautiful! An ocelot!

Jeez, look at the stripes on it!

And he's got such big eyes.

You can tell that he's seeing perfectly clear at night-time.

Oh!

The camera traps have caught cats

returning in the morning after a night's hunt.

Oh, my gosh!

Look at that!

An ocelot with a freshly killed coati in its mouth.

Coatis are daytime animals.

It's likely the nocturnal ocelot caught it while it was sleeping.

Looks like it might be a juvenile.

He's almost the same size as the coati.

But because he's such a perfect hunter,

he's able to take prey up to his own size, or probably bigger.

That's a big meal for him!

Oh, wow!

An early morning puma!

Look at that! That is huge!

Pumas are actually one of the biggest predators in this forest.

They are like the king of the jungle.

They roam around here, and can eat basically whatever they want to.

I came out here to see the big animals and, really,

it doesn't get any bigger than pumas.

That's awesome!

George has seen his ultimate night-time predator in action.

It's time for him to move on to the second phase of the expedition.

His next location is 1,500 miles away

in one of the remotest parts of Venezuela.

He's going to explore a newly discovered cave system.

A place of perpetual darkness.

George wants to discover what strange animals have evolved here

in an isolated world without light.

This cave has remained unexplored for so long

because its entrance is hundreds of metres up a sheer mountain.

George will be the first biologist to set foot in it.

Inside these enormous lumps of rock are caves

and caverns which have been etched out, eroded,

by rain over millennia.

And inside there are animals which haven't seen the sun, ever.

Since these caves were formed.

I can't wait to see what's in here!

There's only one flat place to set up camp.

We're just going to be perched on this little rocky out drop.

I tell you, this is...

this is EXTREME camping! HE LAUGHS

George is joining an international team of explorers.

They discovered the cave in 2009

and are returning for the first time.

Go, go, go!

Well, that's it.

We really are on our own now.

I mean, this is about as foreboding a place as I've ever seen.

Tomorrow, the cave exploration will begin.

They will travel three miles underground

to places light has not touched for millions of years.

As darkness falls on Justine's beach,

she is hurrying to set up a new hide at ground level,

where the jaguars entered the forest last night.

She wants closer shots of the jaguars,

but it's a risky strategy.

It's a bold step, coming off the tower,

where my scent's all up in the air and it's a lot more discreet.

And then being down here,

where I'm right bang in the middle of everything.

That's a big step. And the jaguar might just go, "You know what? No."

"I'm going to go back in the forest."

In the Mayan ruins, a strange sound in the trees

has caught Gordon's attention.

HOWLING

Seems counter-intuitive to walk towards an animal

-that produces this sound, but...

-LOUD HOWLING

It's incredible! Such a spooky noise!

If I didn't know what that was,

I would probably run as fast as I could in the opposite direction!

It's Howler monkeys.

Howler monkeys are daytime animals.

They should be asleep.

Something has disturbed them.

Such an incredible noise!

There we go. Got you!

Howler monkeys are one of the loudest animals on the planet.

HOWLING CONTINUES

Now, it would be nice if this one was to call.

That's typical!

All this noise, and the one and only Howler monkey

that I can actually see isn't calling!

Howler monkeys can't move freely about the trees after dark.

Their night vision is about as poor as ours.

So they use their distinctive call

to scare off nocturnal animals

that come into their territory, looking for food.

Something else is out there.

Where are you? Where are you?

There we go. Right in the middle.

Oh, nice! Look at that!

It's a kinkajou, sometimes called the night stalker.

The kinkajou is an arboreal specialist,

and he's also a specialist of the dark.

-HE LAUGHS QUIETLY

-I would go as far as to say

that kinkajous hate the light.

They'll go into the deepest, darkest hole in the tree

that they can find, spend the day there.

And there's no reason for the kinkajou

to even think about coming out during the day.

It finds everything it needs after dark.

Kinkajous come out at night

when there is little competition for food.

Their whole biology is geared towards

a nocturnal life in the trees.

Large eyes help them see in low light.

But their most important sense is smell.

They use it to navigate in the pitch black.

He's got scent glands on his face,

and a big patch on his stomach,

that he can use to leave a constant trail of scent up there in the tree.

Their scent trail marks every route they take,

so they never get lost in the dark.

Oh, no. Do you know what he's doing?

It looks like he's licking the moisture from the leaves.

So this animal has absolutely no reason to come down to the ground.

For the kinkajou, the ground just signifies danger.

Look at that, hanging completely upside down.

And he can only do that by having that big prehensile tail.

You can see how flexible he is.

And if you can imagine trying to pick fruit

up on these little spindly branches,

you're going to have to be able to

reach and stretch and twist yourself.

And the kinkajou can do that so easily.

He's like a rubber band.

These are really privileged views, actually.

What we're looking at is the result of millions of years of evolution.

The night and the environment shaping an animal

that has become an expert.

They've really earned their name of the night stalker.

In her hide on the beach,

Justine is spending her first night at ground level.

She is alone in the dark,

with the largest cat in the Americas lurking close by.

Got a bit of a speck...

Ah, that looks promising.

Could be a jaguar. Possibly.

Hard to see, though.

It's just a bit of a white glow.

Although it's moving a lot faster than a turtle would.

Ah! It's hard to see anything through this.

SHE SIGHS

Come on.

Where have you gone?

I actually feel quite nervous now.

The thought of actually a jaguar

appearing on the beach in front of me.

I'm just sitting in a hide here, made of cotton.

I haven't really thought about it, up until this moment.

I mean, what if it decides to come up to me, close?

What do I do?

Just sit quietly? Or make a noise?

I don't know.

Looks like a...

..that's a jaguar.

Definitely. That's a jaguar.

He's walking down the line of the forest.

It's that male again.

Scent marking.

It's definitely scent marking.

It's still coming.

If he keeps along this line, he's going to walk right past my hide.

Hopefully he's going to head out to the beach in a minute.

Why don't you head out onto the beach?

No. No, he's going to keep going down this line.

It's getting a bit close now.

Oh, no!

He's walking straight at me.

SHE SIGHS

SHE MOUTHS

Come on. Come on. Stop.

No, he's walking straight at me.

SHE MOUTHS

-SHE EXHALES

-I can't believe it!

He's gone!

He's passed. I thought he was...

I thought he'd stopped outside the hide.

Went out of...he went out of focus, he was so close,

he went out of focus.

I've just caught a glimpse of him further up.

SHE EXHALES

SHE LAUGHS QUIETLY

I don't believe that!

I thought I was mincemeat.

I half-expected to see flailing claws ripping through the hide!

-God!

-SHE SIGHS

I'm going to get hysterical now!

Well, it's dawn now,

and I want to go and see just how close

that jaguar got last night.

Oh, my God!

Look at that! There's my hide, and the tracks are literally...

..there! It went straight past.

I mean, I could have reached out and stroked his back as he went past.

Seeing these tracks next to the hide,

last night is flooding back to me.

My heart was in my mouth.

But now, I just feel strangely elated.

I just feel that I've had such an intimate experience

with this wild jaguar.

The team have ventured into the dark

to uncover the secret lives of highly specialised creatures.

They have witnessed incredible adaptations,

ingenious strategies,

super senses.

Sophisticated adaptations that allow animals

to thrive in a world without light.

And they are just getting started.

Next time, the team head into the dark heart of South America.

Gordon is on the trail of a bizarre night-time creature.

Freaky, freaky!

In the Amazon, camerawoman Sophie comes eye to eye

with the world's only nocturnal monkey.

It's extraordinary!

Just pouncing through the trees! It's just incredible!

And a mile underground, George makes the discovery of a lifetime.

Oh, my God!

Subtitles by Red Bee Media Ltd