The giant otter - six feet long, from tip to tail.
They're known in the Amazon as "wolves of the river".
For me, they hold a special fascination.
Loud, boisterous and aggressive. They're also loving,
affectionate and fiercely protective of their family...
..even if it means risking their lives.
I first filmed giant otters when I was just a young cameraman
and got to know a very small, rather goofy, little cub, called Diablo.
I watched him grow up for almost a year and got very attached to him.
I've often wondered what happened to Diablo.
And now, I'm about to find out.
I last saw Diablo
13 years ago, in Manu National Park,
a remote part of the Peruvian Amazon.
Manu's incredible. The amount of life here blows my mind -
half a million species of insect,
10% of all the bird species in the world.
Nowhere can touch Manu for diversity.
It's a long way from home, back in Britain.
My name's Charlie and I've been completely obsessed with otters
since I was a kid.
I've rescued orphaned otters,
I've spent hours filming and watching otters.
They've all got their own character...
..and many have become like old friends.
In Diablo's case, long-lost friends.
So I can't wait to try and find him again, after all this time.
My journey across the Andes and down into the Amazon Basin
takes me almost a week.
Ooh, just getting swept down.
Where I'm going, means journeying by boat,
far beyond any towns or villages,
right into the headwaters of the Amazon.
Manu - 17,000 square kilometres of pristine tropical rainforest.
I just love this place.
Right in the middle of it, is a stunning oxbow lake
called Lake Salvador.
This is where I last saw Diablo, as a cheeky young cub.
It's late November now, just coming to the end of the dry season.
For the next six months,
me and a small crew of local guides and boatmen
will be calling this place home.
It's four in the morning and I'm just so excited
about finally starting the search for Diablo.
I love the sound of the forest at dawn.
It's loud, it's like a busy city,
but there's one sound that I'm just desperate to hear.
SQUEAKING AND WHISTLING
There it is!
Seeing giant otters again, after all this time...
Well, it's just magical.
SNORTING
Is that not the coolest animal in the world?
But are any of these otters Diablo?
Otters have got unique throat markings, a bit like fingerprints.
If I can get a look at the pattern on each otter's throat,
I might be able to work out if one of them is Diablo.
There's one otter, he's just a bit bigger than the others.
He's the one I want to get a better look at.
I'm trying really hard to get a shot of this otter's chin and throat.
It's definitely Diablo. Wow, there's the man.
That's stunning. I can't believe I'm looking at him.
Just look at him, though. He's rock solid.
He looks healthy, he's big. You know, this guy's 13.
That is as old as giant otters get.
And he looks to me in really good shape.
Giant otters live in family groups - mum, dad and the teenage kids.
I just don't know how big his family is,
but there's just otters everywhere.
Diablo's obviously a very special otter,
to have such a big family like this.
And now that I've found him after all this time,
all I want to do is sit and just watch. They're just so beautiful.
Finally, I get the chance to see Diablo out of the water.
He's busy working on what's politely known as an otter latrine,
in front of what must be the family den.
There's a good reason why Diablo's rubbing his feet around
in the family toilet like this.
It makes the most almighty stink,
which warns other otters that this territory belongs to Diablo.
And then, I understand, why my old friend
is being so protective of his den.
That's a cub. That's a cub.
Oh, my God.
If she's got it in her mouth, that's the mum with it in her mouth.
Wow, look at that. Tiny.
That is really young. That can't be more than six weeks old.'
He's got another one.
There's at least two of them.
Come on. Yeah, yeah.
Seeing otter cubs in the wild like this is incredibly rare.
This is a real surprise.
That's amazing. That is a big family.
This seems to be some sort of swimming lesson.
I know it sounds bizarre, but otter cubs don't actually like water,
so lessons like this are obviously essential.
There's one cub in particular who catches my eye,
not because he's muddier than the others,
but because he really doesn't like the water.
And despite his mum's best efforts, all he wants to do
is get back to the warmth and security of the den.
The other cubs all seem to be enduring their swimming lesson.
Some even look like they're starting to get the hang of it all.
But this little guy - well, he's just not having it.
So in the end, there's nothing for it, but to just pick him up
and dunk him in the water.
Oh, my God.
All of the otters here are given names as cubs,
to help any scientist studying them.
And it seems only fitting to give this little guy a name
appropriate to Lake Salvador, so I call him Dali.
It's hard to count, but it looks like there are six tiny cubs,
which is a record number!
Diablo and mum, Sophia,
are doing the bulk of the caring for the cubs at this age.
They are helped out by the older brothers and sisters,
but even then, they will have their work cut out,
because six is such an unusually large family.
Well, you know, it makes you wonder actually,
how Diablo and the others are going to keep six cubs alive in this lake.
It's actually something that worries me.
Giant otters might be the largest of all the otters,
but they do have an arch enemy here on the lake.
A predator that kills more otters and their cubs than any other.
And I'm heading out into the night to find it.
It's got properly dark now
and suddenly there are just eyes everywhere when I shine my torch.
My boat appears to be surrounded by black caiman.
These guys can grow huge - up to 18 feet long!
They're the largest predator in the Amazon Basin.
Those great big eyes are adapted to seeing in low light
and they've got a very acute sense of hearing,
which makes them perfectly suited to hunt in the dark.
It's quite astonishing, really, just how many caiman we're seeing.
I thought we might see, you know, one or two,
but there are, literally, caiman everywhere.
Caiman are essentially ambush hunters.
What they do is they sit in places like this,
just along the edges of the lake, and wait.
And they can wait and wait and wait.
I mean, they're in no hurry to get fed.
This is why they're such a threat to the otters.
Lurking in the bushes around the edge of the lake,
waiting for any prey to swim past.
There are over 700 black caiman on this lake,
so they're obviously doing very well here.
Diablo and his family are going to have to be super-cautious
to keep those cubs alive.
The next morning, Diablo and the other otters are all by the den.
Something's going on. They look anxious.
There's a great big caiman not far from the entrance.
The cubs are inside,
but Diablo's not going to tolerate any caiman this close to them.
The caiman stands its ground.
This is where having a large family pays off.
Diablo leads the family in.
The gang encircle the caiman, intimidating it.
And Sophia, there she is, moves in to distract it from the front
giving Diablo the chance to bite the caiman right on the end of the tail.
Most caiman will bow out like this,
when faced with a whole family of giant otters.
The dangerous ones are those that refuse to move.
There is another predator around here that Diablo and his family
just wouldn't dare stand up to.
Few of its victims ever even see it coming.
And on our way back to camp, I stumble across evidence of one,
just a stone's throw from Diablo's family den.
Look at this. This is amazing. These are jaguar footprints.
And it's got out the water and it's walked along this beach
and it's done that in the last five minutes. These are still wet.
That's wet sand, and in this hot sun that would have dried out.
Quite daunting and quite exciting
to know that there's a jaguar who almost definitely knows we're here,
just up ahead.
Not quite sure why
I'm following jaguar prints that are just minutes old,
but I have to say it's very exciting.
Just amazing to know that within a few hundred metres
of where I am now is a massive cat.
That's pretty awesome.
To me, the jaguar is the ultimate forest hunter.
If one doesn't want to be seen, well, then, it won't be.
It's quite unnerving to know that a jaguar's living this close
to Diablo and the cubs.
So I'm putting out a camera trap, right outside the otters' den,
just in case the jaguar decides to target the family.
But as we head off, we find signs of an even greater predator
than the jaguar and it's hunting only metres from the den.
This isn't the path of an animal.
It's the path of an uncontacted tribe.
And German, in front of me, can see this path,
which is just the odd snapped stick, which you know,
in a forest, which to me is just a massive tangle of broken sticks,
and he can follow it through, by seeing all these snapped off ends.
He can spot them really well. I mean, he can just follow this path.
To me, you know, we're not on a path. There's nothing on the ground.
But he's navigating us through the forest.
Look, there's another one, been snapped off.
My guides, Juan Andres and German explain that it's the path
of a hunting party from the uncontacted Mashco-Piro tribe.
The broken twigs are their way of navigating through the forest.
So three guys with bows and arrows sneaking through the forest here.
If they're hunting here, I'm worried.
Might they go for the otters?
Nothing from the river. Normally just turtle eggs, but no fish, no.
Nothing from... Just the turtle eggs and peccaries mainly.
Does he think they might...
Maybe they've seen us and we haven't seen them?
No, these are old marks.
They're old. Oh, OK.
Diablo and the cubs live on a lake
that's clearly within the tribe's hunting ground.
So it's a real relief to learn that they're not on the menu.
The forests here might be the domain of the Mashco-Piro hunters,
but out on the lake, Diablo and his family are in charge.
And when it comes to hunting,
there aren't many fishermen who can catch fish as fast as a giant otter.
The family seem to spend their whole time fishing.
I can't believe they never get full.
But then, a fully-grown giant otter does need
around four kilos of fish a day.
What that means is that the most infamous fish of them all
is at the top of the menu - the piranha.
Look at the size of this fish.
Now that is a piranha. Wow.
Very proud of himself. That is good work.
Piranhas are really common on the lake
and Diablo and the others seem to love them.
It makes me wonder though - how can he teach his cubs to take them on
without getting bitten by those razor-sharp teeth?
I've decided to try and see just how aggressive those piranhas are,
by attaching a chunk of meat to an underwater camera.
Ooh, now there's a fish. Ooh, there's a fish.
No, that's a piranha. And another one.
They just pile in, grab it, rip it up, and swim off.
One went in and started and now all the others have started piling in,
they're really going for it.
Those piranhas move really fast.
They've got a very acute sense of smell,
so that's why they can find meat so quickly.
What fascinates me though is how frenzied they are at devouring it.
Less than 30 seconds!
I am amazed at the speed they've torn that piece of meat apart.
Those cubs will have to move at lightning speed,
to catch their dinner without getting bitten.
It's a skill they're going to have to learn.
You've got to admire those otters
because they swim around in this all day long,
and I don't even want to dangle my feet off the end any more.
Swimming lessons for Dali and the other cubs
are now a daily event here on the lake.
And although they're not the best of swimmers,
the cubs are finally starting to get the hang of it.
Moments like this are a really good chance
for the older brothers and sisters to help out, get to know the cubs.
They do all sometimes get a little bit over-excited.
So Diablo and Sophia have to step in, occasionally,
and rescue the little ones.
Building these family bonds is crucial,
because they need to be able
to depend on each other, in times of danger.
And as for little Dali, well, I can see mum Sophia
trying to take him off to one side
so he can get some practise in peace.
He's nearly swimming unaided now,
just about keeping his head above water.
A few weeks have passed.
More and more, I'm noticing a build-up of caiman near the den.
I'm not sure whether this is from the smell of the latrine,
which is really starting to stink now,
or whether the hunting's just better down this end of the lake.
There's one large caiman in particular
they just can't seem to shift.
So today, they've clearly decided to do something about it - move den.
Diablo and Sophia have a cub each and the rest of the family
are flanking them in one big protective group.
They're going a really long way.
I mean, they've been going for ages, right down the centre
and I guess that's cos the caiman are going to be on the edges
and they're really vulnerable when they're like this
having those cubs out.
Even when everyone's backing each other up,
moving like this is a risky business.
Yeah, I can see several caiman along the edges.
And although these guys are essentially ambush hunters,
they're also big opportunists,
so if they see any weakness, they'll go for it and exploit it.
So these otters have got to be careful.
It's the middle of the day
so the otters are banking on the caiman being less active.
All the other members of the family are coming together.
This is where having a big family, being a social animal,
really comes into its own, because this family is now working
as a single unit, to shift those cubs from one den to the other.
OK, so things are looking good.
They've got four cubs across now, which is good.
As long as everyone sticks together, these cubs should be safe.
But then something odd happens.
One of the otters, I think it's Diablo,
has been back to the den alone.
It seems he's the only one who's remembered the two missing cubs.
Now, that is just dangerous.
They're really vulnerable now, carrying that cub on its own.
They need the family. They need the protection of everyone else.
Shouldn't be doing this on its own.
I'm not sure whether he's brave or just taking too big a risk.
I can see a caiman really close.
Just got to steer clear of there.
Just easy pickings for a caiman.
Because to defend itself, the otter has to drop the cub.
This is actually quite dodgy
because this otter is really vulnerable now.
Come on, where are you? Where are you?
There! Ha-ha!
Good old Diablo, what a dude!
Hold on, what's that?
There's two cubs.
That's bizarre. He's carrying two.
He only had one in his mouth. That's amazing!
He's gone up.
He must have had one in his mouth and been carrying the other one.
I've never seen an otter carrying two cubs.
He must just be swapping, juggling, you know.
Holding one in his mouth and the other one in his front paws maybe,
and then swapping them allowing them to breathe.'
I'm very relieved that all six cubs have made it back to the den.
SCREECHING AND SCREAMING
But then all hell breaks loose.
I don't know what's going on in here.
Like, all I can hear is just the loudest screaming and shouting.
They're just... I've never heard them squeal that loudly.
There must be a fight going on.
It sounds to me like something's kicked off with a caiman
and they're all getting involved.
The vegetation's so thick here, it's impossible to see what's happening.
It's so frustrating. I just want to see it.
Just after the commotion ends, a caiman slips out of the forest.
The family slowly reappears in dribs and drabs.
But something doesn't feel right.
Dali looks like he's OK,
but I'm pretty sure two of the cubs are missing.
They must have been killed by the caiman during the fight.
It's so sad.
And to me, I guess it's because I got really fond of them,
I got to know them.
But what's worse about it, what's more tragic, is that
the giant otter population can't afford to lose two cubs like that.
They're just, they're rare, and they needed them.
And it all just seemed so pointless.
But I guess that's just the way things are on this lake.
Diablo's success now rests with the four remaining cubs.
By mid-February, the cubs are growing up fast.
They're all now getting pretty confident in the water
and even Dali's swimming like a pro.
It's lovely seeing him out of the water
playing with his old dad Diablo, like this.
He looks like a very well-fed, healthy young otter.
One of the main reasons everyone's doing so well here
is that the lake's very rich in nutrients,
which makes it absolutely jam-packed full of fish.
And where there's fish,
there's always a load of fishermen lining up to catch them.
Some with eyes bigger than their beaks.
At four months old, Dali and the other cubs
can only really watch the fishing.
They're getting more confident in the water,
but they've got a long way to go
before they can catch their own fish.
They're still very young and vulnerable, but if they make it
through the next few months and learn to fish for themselves,
they've got a good chance of making it to adulthood.
For now, they're still relying on the rest of the family for food,
but to get it, they've got to beg.
And Dali, in particular, seems the most persistent.
Although Diablo's not going to give up his breakfast that easily.
Fishing plays such an important role in the otters' lives
and I find it so frustrating that most of it goes on out of sight.
So I've come up with a simple invention -
one small waterproof camera taped to my water bottle.
And what I want to do with this device is stick it in the water
and then bank on the otters', sort of, natural curiosity,
and hope they'll come up and have a look at it
and I'll then get a decent look at them underwater.
You can really see the size of the webs on their feet.
They're almost like flippers.
In this muddy water, my bottle cam can't film very much
but it does remind me of the only other time
I've filmed these animals underwater.
Back then, I got some great pictures of their amazing swimming abilities.
So fast and able to instantly change direction to grab a fleeing fish.
It must be the huge, flat tail that gives them such a turn of speed.
Diablo's cubs are too small at the moment to move like these adults.
They lack the power.
Going out into the lake, watching the parents hunt,
is how the cubs learn,
which is why fishing trips like this, with the family,
are now becoming a daily event.
Dali, like the other cubs, seems to be a bottomless pit -
he's constantly harassing the adults every time one of them gets a fish.
He can't swim and eat at the same time, though,
so he's got to go ashore with his prize.
The problem with that is that now he keeps going missing
in the bushes along the edge of the lake.
Today, the family's chased fish right up the lake,
and it looks like poor old Dali's been left well and truly behind.
Yeah, I hope there aren't any caiman about,
cos he's really squeaking.
DALI GIVES A HIGH-PITCHED SQUEAK
And if any caiman hear that...
..they'll go in for him,
cos he's really vulnerable on his own like that.
Oh, I can see one in the bushes...
but he's not moving.
The family have realised Dali's missing -
they're all calling out to him.
SQUEAKS AND GRUNTS
They are a bit dopey sometimes,
cos they're all screeching their heads off,
but they're never waiting to listen for a reply.
CALLS CONTINUE
The family all head back to the area where they last saw Dali.
DALI SQUEAKS
SQUEAKING
It's a relief when Diablo finally spots his son.
I love it when they greet each other.
There is definitely affection there.
It's definitely, you know... They're pleased to see each other.
Earlier in the season,
I put a camera trap out in front of the family den,
to try and find out if a jaguar might be hunting in the area.
I reckon it's time to have a look and see if it's filmed anything.
There's the otters outside the den.
Probably getting ready for bed.
And then out of the darkness emerges a cat I never thought I'd see.
Look, look at that! Oh!
Not a jaguar, but an ocelot.
I've never seen an ocelot in the wild.
They're mostly nocturnal hunters
and, given half the chance, they'd take an otter cub.
The fact that there are predators like this ocelot on the prowl
is probably why the otters are out during the day
and tucked away in the safety of the den at night.
Watching a shot of an ocelot like that is pretty special.
Well, that was worth putting this out for.
But then I can't believe my luck.
There's a jaguar!
HE CHUCKLES Oh, my God!
That is stunning.
Big male jaguar.
That is unbelievable.
What an incredible creature.
What a treat.
It's amazing to know that...
..everywhere we walk around here...
..these massive cats are also wandering around.
And I bet they see us all the time.
There he goes.
Well done there, man.
That was a BIG animal.
It's pretty awe-inspiring to see a massive jaguar like that.
But knowing that they're living and hunting so close to the otters
does worry me. Not just for Diablo and his family, but also myself.
I've been watching the giant otters for nearly four months now.
And what's impressed me most about them
is just how nice they are to each other.
Yeah, they get a bit boisterous occasionally,
but it's all good fun.
SQUEAKING
They seem to me to be a really happy, tight-knit family.
Even if old Diablo likes to slip away
for a bit of peace and quiet every now and then.
Dali's gone from strength to strength
and he's really starting to explore the world.
But the large caiman's back again.
As usual, it seems to be lurking right by the den.
The otters are on high alert.
They all want to keep him in sight.
Diablo seems especially twitchy.
The caiman's blocking the way to the den.
The cubs are in the water, so no-one's taking any chances.
The caiman has to be moved on.
All the adults move in to harass it.
The cubs keep their distance.
Sophia goes in at the front, sizing up the caiman.
THE OTTERS SNORT
Others move in to try to distract it,
giving Diablo his chance to go for the tail.
But the caiman still won't budge.
Then it goes for him.
THE OTTERS CALL IN ALARM
The cubs panic and follow the adults right into the middle of the fight.
By the time the caiman realises that it's outnumbered, it's too late.
The otters step it up.
They overpower the caiman, some holding it down,
others biting it in the head.
After an hour of fighting, it's all over.
The caiman may be dead, but I need to know if the otters are all OK.
It doesn't take long to realise two of the cubs are missing.
It's kind of hard when you...
when you...see an event like that, because on the one hand
it's, you know, undoubtedly an incredible thing to see.
You know, giant otters taking on a caiman...and winning!
But on the other hand, you know, we lost two cubs.
I find that really hard because...
..I've watched these cubs since they were tiny.
You know, just a few weeks old.
And you know, they'd done really well.
They'd got, you know, they'd gone so far.
And then to see the caiman killing them...
Well, it kind of, it was a moment that destroyed the whole family.
And...
..I guess that's why they went from this,
you know, loving family - happy, playing around, fishing -
to these angry, furious killing machines.
Biting it in the head, ripping it apart underneath,
at huge risk to their own lives,
in order to, I guess, kill the thing and eliminate it from the lake.
You know, that caiman was a threat to their family
and they had to get rid of it.
THUNDER CRACKS
WATER DRIPS
A week after the fight, the rainy season finally kicks in.
I haven't seen the otters for days
and can't be sure which cubs are still alive.
There's just no let up in the weather -
the lake and surrounding forests are completely flooded out.
The downpours are torrential and they're not stopping.
It's making just travelling through the forest almost impossible.
THUNDER BOOMS
Our camp's now flooded out and our equipment's starting to fail.
We've got no choice but to evacuate.
THUNDER CRACKS
A month later, the weather's better
and I'm travelling back upriver to look for the otter family.
I'm apprehensive, though.
I've no idea if Dali's alive.
I don't even know if the family's living on the lake anymore.
OTTERS SQUEAK
So I'm very relieved when I hear the familiar shrieks.
But before I get too excited, I want to know who's left.
It looks, from what I'm seeing here, there's only six.
Sadly, there's no sign of my old friend, Diablo.
But of the otters I CAN see here,
two in particular are of real interest.
I can see there's two cubs left.
I mean, they don't look like cubs any more. Probably that big?
And one of them is Dali.
I spend the morning with the otters
and follow them as they head off fishing.
The two cubs have really grown since I last saw them.
They're so much bigger and bolder now.
Dali might still be smaller than the others,
but he's got real attitude,
and seems to love throwing his weight around.
It amazes me that these two cubs have managed to survive so long.
I've seen the odds they face.
But there's still one big hurdle I want to see them overcome.
That's the cub. He's caught his own fish.
He's got his own fish!
That's a major breakthrough.
That's the first time I've seen one of the cubs catch their own fish.
And that is a major life moment for an otter cub,
not to be fed by Mum and Dad,
not to go and steal a fish off another otter,
but to actually catch its own fish finally means it can feed itself.
That's like the last major hurdle
going from childhood into adulthood for an otter,
is to catch its own fish and he's just done it.
These cubs when I met them, they were this big.
They were totally helpless, totally useless,
totally dependent on Mum and Dad and the family
to do everything for them.
And now they're proper otters, they're six months older.
You know, and they're catching fish.
And that means that their chances of survival have just skyrocketed.
And then I'm relieved to see a familiar face.
It's Diablo.
It's down to this devoted father that the cubs have made it this far.
And if they can go on to be even half as prolific as their dad,
the giant otter population here in Manu will be in good hands.
In a place like Manu, which is one of the last strongholds
of these incredibly rare animals, that's hugely important
that we've just got two new otters into that population.
And that's a lovely thing to have sat here
and witnessed over the last six months.