[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.
Evening is falling in the world's greatest tropical wetland.
Brazil's Pantanal.
[birds chirping]
A stronghold for South America's most secretive big cat...
the jaguar.
And enjoying the last warmth of the day is a male
-[purrs] -known as Juru.
At six years old and weighing over 100 kilos...
[purrs]
...he's amongst the largest,
most powerful big cats in the Americas.
This prime stretch of river has been his territory for two years.
[bird chirping]
But tonight Juru's reign hangs in the balance.
In a recent fight with a rival male, he badly injured his paw.
It's left him weak and hungry.
The coming days and nights will test him more than ever before.
He'll need to summon the strength to defend his river.
But this evening, his first priority is finding something to eat.
To hunt, Juru must have the element of surprise.
But in daylight,
his injured paw makes sneaking up on prey almost impossible.
[otters chirping]
A family of giant otters has spotted him.
[roars]
[chirps]
It seems there's little chance for a meal in daylight.
But the jaguars here are largely nocturnal.
They're twice as active at night.
Juru knows the coming darkness may bring him success.
[birds squawking]
As the tropical sun sets...
the river transforms.
Until now, what jaguars got up to at night on these rivers...
has been a mystery.
[birds squawking]
But with cameras that can film only by moonlight...
we can now see their nighttime world...
in color.
[birds chirping]
[squawking]
Allowing us an intimate view into Juru's life.
And giving us a window into the night on his river.
After hours resting his injury, his first steps appear excruciating.
But he's got no choice.
He must try to hunt.
His night vision, six times more sensitive than our own,
picks out a group of capybara,
giant rodents that live on the river.
Jaguars are ambush predators.
Juru must get within meters of his prey to stand a chance.
But now at night...
he has darkness on his side.
The capybara can't see him.
But our cameras can.
Despite his injury...
he's closed the distance.
[barks]
[barking]
With the capybara in the water, Juru needs a different approach...
and reveals something truly remarkable.
At night, jaguars here are aquatic hunters.
Relieved from the pain by the water,
Juru now uses the river as a stalking highway.
Until we followed Juru,
no one knew the extent to which jaguars stalked rivers like this at night.
[barks]
He's managed to creep up on the capybara.
But they're skittish.
And alert.
[barks]
-He's been rumbled. -[barking]
[barking]
-[barks] -[barks]
It's just not Juru's night.
But he needs to eat soon to have the strength to continue to rule.
In the savanna that borders Juru's wetlands...
the night reveals one of South America's most mesmerizing light displays.
These beacons are produced by click beetle larvae
emerging from their burrows in termite mounds.
For a few weeks a year...
each mound, some up to three meters tall...
lights up the night sky.
The night also draws out winged termites
that fly between the mounds to breed in their millions.
But for the termites, the lights are lethal.
They're attracted to them like moths to a flame.
But it's a trap.
The glowing grubs are termite hunters.
They'll feed on the corpses in the darkness of their burrows...
in one of nature's most sinister,
but magical midnight feasts.
[thunder rumbling]
Back on the river, two nights have passed.
Juru still hasn't eaten.
He's weaker than ever...
and now faces a new problem.
[low roar]
In the darkness...
[low roar]
...he hears a distant roar that could be a rival male.
[low roar continues]
But night cameras show...
it's something more enticing.
[low roar continues]
It's the mating call of a young female jaguar called Ague.
She's calling to attract a partner
and appears to be following the scent of Juru and other males
that have passed along the beach.
[low roar continues]
She's only in heat for a matter of weeks.
So hopes tonight her calls will be answered.
She spots something emerging from the dark...
but it's definitely not what she was hoping for.
A Brazilian tapir...
one of South America's rarest nocturnal creatures.
Ague doesn't know whether to attack or retreat.
[bird cawing]
Luckily for the tapir,
Ague's still got her mind on finding a mate.
[cawing]
[low roar]
And all her calling at last attracts attention.
[low roar]
But this powerful male isn't Juru.
He's an intruder...
[low growl]
...a threat to Juru.
But just what Ague has been looking for.
Big cat courtship is usually a raucous affair.
But seeing into their nighttime world shows it can be far more gentle.
The young couple sit together as if on a first date.
Seemingly happy just to be close to one another.
[bird cawing]
And tonight they're not the only ones on the river
for whom love is in the air.
[roars]
Choosing the right partner takes a bit of time.
[chirps]
[caws]
[roars]
Following Ague through the night
reveals a surprisingly tender side to jaguar courtship
filmed for the very first time.
[roars]
Ague has got her man.
But for Juru, control of the river is slipping away.
Two evenings later, he remains alone...
and still hungry.
He hasn't eaten for a week
but must do soon to keep hold of this prime territory.
In the two years this has been his river,
it's the hardest time Juru's ever faced.
But he's not about to give up yet.
His paw is healing.
As dusk draws in, hunger drives him on.
Now stronger, he can hunt the river...
in a different way.
He spots a capybara seeking shelter in the reeds.
But he's not the only hunter here.
A yacare caiman.
Two meters long, and another top predator also on the prowl.
Juru must move slowly to avoid raising the alarm.
But tonight he's not after capybara.
For a hungry jaguar,
even other predators are on the menu.
The most powerful jaws of all big cats finish the fight.
A prize like this will be devoured in hours...
but will sustain Juru for days.
Juru is finally back on form.
As another night descends,
Juru is back patrolling his realm.
Over the many moons he's ruled this river,
this last has been his toughest.
But against the odds,
Juru is ready to face whatever new challenges may come his way.
Only by seeing into his world at night
have we been able to tell the full story of Brazil's jaguars
in a way never possible before.
To film jaguars in Brazil's Pantanal,
the Earth at Night team had to take to the water
using filming boats armed with specialized night cameras.
The crew weren't searching for just any jaguar,
but one cat in particular. Juru.
[man] We're looking for Juru.
We lost him into the forest,
and we're thinking he may pop out onto one of these beaches
that have been lit up by the moonlight now.
[man 2] Really would like to find Juru. Feels like a needle in a haystack.
I mean, to find a jaguar is fortunate around here.
And to find a given jaguar that's our star, it's asking a lot.
[Tom Hiddleston] The team's years of experience following and filming big cats
was being put to the test.
[Stevens] The guides know these cats really well.
They've spent hours with them during the day.
But no one's ever done this at night before.
So it's, um, it's new for everybody.
[Tom Hiddleston] Juru's territory stretches for up to 100 square kilometers.
So just finding him at night was an achievement.
It's 4:15 in the morning. We've been out here for 12 hours.
And we found him.
Right, he's just... popped his head out.
Looking around, he's not that alert. He still looks quite sleepy.
[Tom Hiddleston] Having found Juru,
the crew now relied on the night cameras to see into his world.
If I glance up and look at the riverbank, there's no way I can see the cat there.
It's way too dark. These cameras are phenomenal.
[Tom Hiddleston] With this new approach, the team could follow Juru
and capture the otherwise secret moments of his nocturnal story.
-[Moore] Look, in the water. -[man 2] A bit to the left.
[man 1] The capybara is approaching the jaguar.
[barks]
It's amazing.
[Tom Hiddleston] But it wasn't just Juru
who would give the crew a surprising insight
into what jaguars get up to under moonlight.
There's another jaguar on the beach over there.
It's straight-- It's straight ahead, like, 12 o'clock.
The jaguar's coming towards us.
[men speaking Portuguese]
[Tom Hiddleston] The crew's encounter with Ague
was about to reveal a softer side to this otherwise fearsome predator.
-Oh, wow. -[man] Ah, look at that.
[chuckles]
-[Stevens] That's really nice. -[Moore sighs]
[Tom Hiddleston] This behavior has never been seen, let alone filmed before.
We are now following a courting couple into the night.
[Moore] They're actually pretty tender with each other. It's interesting to see.
Total lovebirds.
I think the book on jaguar behavior is being--
being written right here.
[Tom Hiddleston] Being able to follow Juru and the other jaguars at night
marks a whole new chapter in our understanding
of these secretive big cats.