[Tom Hiddleston] The night.
A shadowy world that hides more than half the animals on our planet.
Until now, cameras only offered a glimpse into their lives.
But with next-generation technology,
we can see the night as clear as day.
With cameras a hundred times more sensitive than the human eye...
we can now capture the beauty of night...
in color.
Alien landscapes.
Strange creatures brought to life by the darkness.
Unseen behaviors.
Now we can follow the lives of animals
in Earth's last true wilderness.
The night.
Sunset over the jungles of Southeast Asia.
And one of the oldest rain forests on the planet
is about to undergo an extraordinary transformation.
[jungle sounds]
As dusk draws in...
the day shift comes to an end.
[bird chirping]
But here in the tropics, more animals have turned to the night...
than anywhere else on Earth.
Their stories and the secrets of this ghostly world have been a mystery...
until now.
Deep in the twisted roots of a giant strangler fig tree...
[creaking]
...hidden from view...
lives, perhaps, the most bizarre nighttime creature of all.
The spectral tarsier.
Tiny primates barely larger than a tennis ball.
This close-knit family is three generations together.
The grandparents...
their grown-up kids...
and two tiny new arrivals.
The youngest, a timid two-week-old...
still feeding on his mother's milk.
And his older cousin, a toddler.
Five weeks old, just finding his feet.
Eager to discover exactly how tarsier life works.
[tarsier squeaks]
Just keeping these two youngsters safe through the long night ahead...
will be a daunting challenge.
[squeaks]
[thuds on ground]
The family have definitely got their work cut out.
-[bird chirps] -[fluttering]
Each night, the tarsiers' first task...
is a bit of unusual personal grooming.
Ear tugging.
It looks painful, but this is important preparation for hunting...
priming their ears to maximize their sensitive hearing.
Each family member has its own unique way of doing it.
Some more thorough than others.
Next... it's time to hunt.
Tarsier night vision is a hundred times better than ours.
But now, low-light cameras...
can see their nocturnal world...
as clearly as they do.
Each night, tarsiers must eat a tenth of their body weight in insects.
One-third again if they're feeding a little one.
From the safety of his home tree,
the five-week-old watches on as the adults hunt.
In just a few weeks' time, he'll need to do it all for himself.
There's lots to learn.
He must master his satellite-dish ears,
moving each one independently to pick up tiny sounds in the dark.
Next, his huge light-bucket eyes.
Once fully grown, each eye is bigger than a tarsier's brain.
He must learn to tilt his head to judge distance.
For the adults, this helps them pounce with pinpoint accuracy.
And there's one final lesson.
At family mealtimes...
it's first come...
first served.
It's time for the family to venture deeper into the forest.
The little ones are too small to travel far.
So they rely on their mothers to carry them...
in their mouths.
No easy task.
One in five tarsier babies are lost in their first month.
So for the tiny two-week-old...
leaving the safety of the family tree...
is a giant step.
Filming the family deeper in the forest than ever before...
we can now see the secret way tarsiers keep their young safe through the night.
Not just one...
but two tarsier babies...
left hidden in the same tree.
A tiny tarsier nursery, never filmed before.
Two cousins watching each other's backs...
leaving the adults free to hunt.
But tarsiers aren't the only hungry predators to emerge after dark.
For a Minahassa masked owl, a baby tarsier would make a tasty meal.
It's going to be a long night ahead.
[bird chirps]
In the first hours of darkness...
[bird chirps]
...not everything is hiding in the shadows.
Along the waterways...
the trees come alive with one of the night's greatest wonders.
Fireflies.
The brightest flashes are males looking for love.
At first, they seem random.
Each working to their own beat.
But slowly, they synchronize.
Flashing in unison, each tree becomes a beacon in the darkness.
Drawing in females with this hypnotic display.
As a female approaches, the males' flashing intensifies.
Captured in astonishing detail...
We can see the chemical reaction that creates this magical bioluminescence.
As a full moon rises, light floods the forest.
And this dazzling display comes to an end.
For the tarsiers, the full moon spells danger.
[squeaks]
The extra light allows them to venture deeper into the forest
than at any other time.
But the further they go,
the more likely they are to run into predators.
Taking a chance...
[squeaks]
...these tree-climbing specialists...
do something unexpected.
They drop from the safety of the branches...
to ambush creatures on the ground.
[buzzing]
For these tiny primates,
the forest floor is packed with treats.
High above, hidden in the branches...
the two tarsier babies watch their family foraging below.
The five-week-old...
is almost ready to start hunting for himself.
[squeaks]
He's still mastering how to move through the forest.
But he is old enough to recognize a tasty snack when he sees one.
A rich feast...
too tempting for a hungry youngster.
[buzzing]
But at night...
you've got to be quick to catch your prey.
A giant Sulawesi tarantula takes this meal.
In a forest full of dangers...
it's time for the youngster to make one of his very first leaps...
back to the protection of mum.
[squeaks]
[water splashing]
Tarsiers aren't the only animals taking advantage of the full moon.
At a jungle waterfall...
two rivals are sizing each other up.
A black-spotted rock frog has secured a prime feeding position.
But a gang of bigger Sabah splash frogs are after his spot.
Normally, a sharp call would tell them to back off.
[chirps]
But next to a waterfall...
it's hard to make yourself heard.
So they use a secret sign language.
[chirps]
-They wave at each other. -[chirps]
[chirps]
The white skin between their toes...
glinting in the moonlight, is a warning.
But the bigger splash frog has a special move.
The double-legger.
The rock frog stands his ground.
And when neither of them back down...
there's only one way to settle things.
[chirps]
[splash]
This time, there is no winner.
The night is almost over.
High in the canopy,
the tiny two-week-old waits for his mother to return from hunting.
Being all alone in the forest...
-[bird chirps] -[squeaks]
...is a scary business.
A reticulated python.
An adult snake would be too heavy to climb high into the canopy.
But this is a juvenile...
an excellent climber.
With the same muscles it would use to strangle its prey...
the snake can ascend the thinnest of branches.
Any unsuspecting tarsier would make the perfect meal.
But these social primates have a clever way to keep their family safe.
The moment they spot an intruder, they sound an alarm.
[squeaks]
-[squeaking] -Three rapid squeaks...
[squeaking]
...the call for the highest level of danger.
[squeaking]
The alarm brings the adults together to mob the snake.
[squeaks]
[squeaking]
[squeaks]
[squeaking]
[squeaks]
[squeaking]
Leaping from branch to branch,
they create the illusion of more attackers.
[squeaking]
-[squeaks] -It may be risky...
[squeaking]
...but tonight...
it works.
Only once the danger has been seen off...
do the adults return to collect their youngsters.
As dawn approaches,
the family returns to the safety of the home tree.
Six adults...
a mischievous five-week-old who tried hunting for the first time...
and a tiny two-week-old...
who survived one of his very first nights out...
deep in the jungle.
[Tom Hiddleston] To film the nocturnal lives of tarsiers...
the Earth at Night team traveled deep into the forests of Southeast Asia.
While one crew followed the tarsier family on the ground...
specialist climber Tim Fogg was tasked with filming in the canopy at night.
Ten stories up.
[Fogg] It's all-- It's all very well doing this sort of thing in daylight,
when you can see everything that's going on,
but we're trying to take it on at night
and that adds layers and layers of problems.
You obviously look down. You can't see what's happening.
[man on radio] You're holding it down on nothing.
[Tom Hiddleston] To get the opening shots of the strangler fig tree,
the team had to balance a low-light camera on a stabilized pulley system.
[Fogg] That's still too heavy. Take some out.
Whoa! Steady! Careful! Okay, that's it!
[Tom Hiddleston] With the rig ready to go...
Tim had to wait for the moon to rise to give enough light to film.
[bird chirps]
On the ground,
cameraman Mark Payne-Gill prepared to film the tarsiers
with a specially adapted lens, built for a very different purpose.
The great thing about this lens is that it's designed
for astronomers to film or photograph very faint objects in the night sky.
All right.
This will be the first time I've ever had to run around a lens of this kind
on any shoot, to be honest.
[Tom Hiddleston] The crew's aim,
to capture the moment when a tarsier baby is left alone in the jungle.
Having hauled the heavy kit many kilometers through the forest,
they finally discovered a hiding place.
[Payne-Gill] Okay, I got it. This is nice.
Yeah. It's great.
Wow.
Hard to believe this little thing just stays there all night on its own
with nothing to defend it.
And just wait for its mum to come back in the morning.
[Tom Hiddleston] Fifty meters up, the night skies eventually cleared,
revealing a full moon.
[Fogg] Okay, here we go.
[Tom Hiddleston] And the crew got to work.
[man on radio] Uh, yeah, that looks amazing. Thanks, Tim.
[Tom Hiddleston] From the canopy to the forest floor...
the team was able to document the secret lives...
of one of the jungle's strangest nocturnal creatures.