0:00:15 > 0:00:17The decision to adopt is never easy.
0:00:17 > 0:00:20But just imagine if your new baby needs to grow up
0:00:20 > 0:00:23in a completely different world from you.
0:00:25 > 0:00:29Carolina Vargas studies giant otters.
0:00:31 > 0:00:34But nothing has prepared her for raising an orphaned cub.
0:00:36 > 0:00:37CUB SQUEALS
0:00:39 > 0:00:43Just keeping him alive will be difficult.
0:00:43 > 0:00:47Returning him to the wild will lead them both into uncharted waters.
0:00:48 > 0:00:52No one in Brazil has attempted this before.
0:00:52 > 0:00:54Raising baby Sancho
0:00:54 > 0:00:57will bring Carolina joy,
0:00:57 > 0:00:58frustration
0:00:58 > 0:01:00and heartbreak.
0:01:00 > 0:01:01SANCHO SQUEALS
0:01:04 > 0:01:07But it will also give her extraordinary insight
0:01:07 > 0:01:09into the lives of these endangered animals.
0:01:19 > 0:01:21SANCHO SQUEAKS
0:01:28 > 0:01:32In south-west Brazil lies the world's largest wetland,
0:01:32 > 0:01:35the Pantanal.
0:01:37 > 0:01:41It's a vast, ever-changing landscape of impenetrable swamps
0:01:41 > 0:01:42and forgotten backwaters.
0:01:44 > 0:01:47And one of the last remaining strongholds of the giant otter.
0:01:51 > 0:01:54These charismatic animals have had an almost magnetic effect
0:01:54 > 0:01:56on one woman.
0:01:58 > 0:02:01Carolina Vargas had embarked on a career as a city vet,
0:02:01 > 0:02:04but when she discovered this maze of waterways
0:02:04 > 0:02:07and the endearing nature of wild otters,
0:02:07 > 0:02:09it was love at first sight.
0:02:11 > 0:02:15BRAZILIAN ACCENT: Since the first time I saw a group of giant otters,
0:02:15 > 0:02:17I got completely in love with them.
0:02:17 > 0:02:21And I really appreciate the way they live, the social behaviour
0:02:21 > 0:02:24and the care and respect they have between them in a group.
0:02:24 > 0:02:27And I think they are really beautiful and expressive.
0:02:27 > 0:02:31I like the way they show their feelings in their faces.
0:02:31 > 0:02:34And, I think I'll never get tired of watching them.
0:02:35 > 0:02:39Carolina left her home, her job and her family
0:02:39 > 0:02:41and moved to the Pantanal,
0:02:41 > 0:02:44eager to take on a new role as Giant Otter Researcher.
0:02:47 > 0:02:51They are inquisitive animals, but that has led them into trouble.
0:02:52 > 0:02:56It's made them easier to hunt, and demand for their soft fur
0:02:56 > 0:03:00has pushed them to near extinction in many parts of South America.
0:03:03 > 0:03:06But they seem to be doing well here because it's so remote.
0:03:11 > 0:03:14Carolina wants to understand how they live
0:03:14 > 0:03:16and what they need to survive.
0:03:18 > 0:03:20But, just two years into her research,
0:03:20 > 0:03:22life took an unexpected turn.
0:03:24 > 0:03:29A local fisherman found a baby otter, alone and destitute.
0:03:32 > 0:03:35He was clearly too young to make it on his own.
0:03:39 > 0:03:45No one knew what to do with him, so rangers called on Carolina.
0:03:45 > 0:03:48Without her immediate help, he would die.
0:03:53 > 0:03:56Even though she had no experience of raising otters,
0:03:56 > 0:04:00Carolina decided she could not let him down.
0:04:00 > 0:04:03She named him Sancho, put her research on hold,
0:04:03 > 0:04:05and became his surrogate mother.
0:04:08 > 0:04:11It's been hands-on right from the start.
0:04:17 > 0:04:21Sancho was very small when I took him off the local rangers.
0:04:23 > 0:04:26He had the eyes still closed,
0:04:26 > 0:04:30so I think he was about 20 days old.
0:04:30 > 0:04:37Very small and he usually spent most of the time sleeping.
0:04:42 > 0:04:44It was very hard because, in the beginning,
0:04:44 > 0:04:46he had to be bottle fed.
0:04:46 > 0:04:49Each took two hours, night and day.
0:04:52 > 0:04:57He just woke up to feed and sleep again and I got this routine,
0:04:57 > 0:05:02so I had to to wake up to feed him and after that I slept again,
0:05:02 > 0:05:04to recover my energy.
0:05:07 > 0:05:09SANCHO SQUEAKS
0:05:13 > 0:05:15We kept him in a dry place in the first two months
0:05:15 > 0:05:18and gradually we put him in the water,
0:05:18 > 0:05:24just to make him swim and... get used to the water.
0:05:27 > 0:05:31SANCHO SQUEALS
0:05:31 > 0:05:34We didn't know how to deal with him, cos it's the first time
0:05:34 > 0:05:39this work was done in Brazil, and we got the information we had
0:05:39 > 0:05:43about giant otters in the wild and tried to copy that routine.
0:05:43 > 0:05:49So, we stimulated him to do things the giant otters do in the wild.
0:05:50 > 0:05:54Sancho's made a good start, but now he's a lot more active
0:05:54 > 0:05:58and Carolina will have to work hard to keep up.
0:05:58 > 0:06:01Each phase of his development throws up new problems
0:06:01 > 0:06:04which he will have to solve along the way.
0:06:05 > 0:06:07SANCHO SQUEAKS
0:06:14 > 0:06:18If she's to give Sancho any real chance of returning to the wild,
0:06:18 > 0:06:22she's going to have to think back to what she's observed along the river.
0:06:31 > 0:06:33Her field notes on wild otters
0:06:33 > 0:06:36will have to serve as a makeshift parenting manual.
0:06:41 > 0:06:45This is turning out to be the biggest challenge of her life.
0:06:50 > 0:06:53One of the main problems Carolina faces,
0:06:53 > 0:06:55is bringing up Sancho on his own.
0:06:57 > 0:07:01In the wild, he would be part of a large, intimate family.
0:07:04 > 0:07:06One group she's been studying is a family of ten,
0:07:06 > 0:07:10with three young cubs about the same age as Sancho.
0:07:14 > 0:07:17Everything she's learnt about the dynamics of this family
0:07:17 > 0:07:20will now help her work out what Sancho needs.
0:07:36 > 0:07:39This is Italo, the dominant male of this group,
0:07:39 > 0:07:42and he's always the first one
0:07:42 > 0:07:46to approach the boat and say hello.
0:07:50 > 0:07:53Understanding the subtle relationships between each member
0:07:53 > 0:07:57of the group has required many hours of patient observations.
0:08:09 > 0:08:12Fortunately, there's a relatively easy way
0:08:12 > 0:08:14of telling each giant otter apart.
0:08:18 > 0:08:24In order to identify them, I use the white marks they have on their neck,
0:08:24 > 0:08:28and when they do this kind of movement, the periscoping,
0:08:28 > 0:08:31it's the best time I have to catch the mark.
0:08:33 > 0:08:36OTTER SNORTS
0:08:40 > 0:08:42Now Carolina knows who's who,
0:08:42 > 0:08:46she can start to work out their roles within the family.
0:08:47 > 0:08:51It's very important to identify them, to know exactly what they are doing,
0:08:51 > 0:08:54like Italo. It's part of the job.
0:08:54 > 0:08:59He's taking care of the group and...
0:08:59 > 0:09:01OTTER SNORTS LOUDLY
0:09:02 > 0:09:04Italo, the dominant male,
0:09:04 > 0:09:07is constantly communicating with everyone else.
0:09:07 > 0:09:10OTTERS SNORT AND CALL
0:09:12 > 0:09:16Compared with other otters, giants are highly articulate
0:09:16 > 0:09:19and have an extraordinary repertoire of noisy calls.
0:09:22 > 0:09:25Alarm snorts, screams of excitement
0:09:25 > 0:09:29and hums of reassurance, all help maintain cohesion in the troop.
0:09:31 > 0:09:34And the cubs learn a lot from these elaborate vocalisations.
0:09:34 > 0:09:37OTTERS SQUEAL
0:09:47 > 0:09:50Carolina has picked up some basic otter language,
0:09:50 > 0:09:55but she's far from understanding the complexities of giant otter society.
0:09:55 > 0:10:00And she's concerned this could be a major disadvantage for Sancho.
0:10:07 > 0:10:10She has no idea whether she can teach a solitary otter
0:10:10 > 0:10:12how to survive in the wild.
0:10:13 > 0:10:16But she knows that that's the best place for him,
0:10:16 > 0:10:19and wants to return him as soon as she can.
0:10:20 > 0:10:24For now though, she concentrates on getting him into a routine.
0:10:26 > 0:10:28Giant otters are active during the day,
0:10:28 > 0:10:31so at first light, Carolina wakes Sancho from his den.
0:10:33 > 0:10:35Giant otters live in family groups
0:10:35 > 0:10:41and the cubs spend two years or three years with the parents.
0:10:41 > 0:10:44And so, I believe they need this contact with their parents,
0:10:44 > 0:10:49just to learn...how to be a giant otter.
0:10:51 > 0:10:54Sancho hasn't got that. But at least he's got Carolina.
0:10:54 > 0:10:56SHE CALLS: Come, come, come.
0:10:56 > 0:10:59And because he's such a sociable little thing,
0:10:59 > 0:11:01he's already very close to her.
0:11:10 > 0:11:12Come, come, come, come.
0:11:12 > 0:11:15Sancho recognises me as his mother.
0:11:15 > 0:11:19That's why I believe he's very bonded with me.
0:11:19 > 0:11:22Actually, I feel like he's my son, too.
0:11:22 > 0:11:26SANCHO SQUEALS
0:11:26 > 0:11:31At four months old, Sancho is already a very demanding cub.
0:11:32 > 0:11:37He's now weaned off milk and has a growing appetite.
0:11:37 > 0:11:40SQUEALS EXCITEDLY
0:11:42 > 0:11:45The excitement with which he handles his first fish of the day
0:11:45 > 0:11:49is something Carolina has never seen before in the wild.
0:11:51 > 0:11:55It's time to introduce him to his real home.
0:12:01 > 0:12:03The pulse of life in the Pantanal
0:12:03 > 0:12:07is driven by a seasonal cycle of floods and droughts.
0:12:09 > 0:12:13October storms herald the onset of the wet season.
0:12:13 > 0:12:16Heavy rain swells the Paraguay River,
0:12:16 > 0:12:20until she bursts her banks and floods an area the size of England.
0:12:24 > 0:12:28For the next six months, savannahs and forests are transformed
0:12:28 > 0:12:32into a land of swamps, pools and channels.
0:12:35 > 0:12:38The slow-flowing water is rich in nutrients,
0:12:38 > 0:12:41nurturing forests of aquatic plants.
0:12:45 > 0:12:49This is the perfect nursery for more than 300 species of fish.
0:12:53 > 0:12:56It's a giant aquarium, bursting with life.
0:12:59 > 0:13:02And that's why giant otters do so well.
0:13:13 > 0:13:16But they aren't the only predators here.
0:13:25 > 0:13:27And for an inexperienced otter,
0:13:27 > 0:13:30the Pantanal can be a very treacherous place.
0:13:36 > 0:13:40It's up to Carolina to help steer Sancho away from danger.
0:13:45 > 0:13:49But even she can't always see what's lurking below the surface.
0:13:51 > 0:13:54And he's already had one very close call.
0:13:58 > 0:14:01When Sancho was younger, he was very vulnerable
0:14:01 > 0:14:05and I had to watch out for him all the time.
0:14:05 > 0:14:11Probably, he was good prey for cayman, anacondas, maybe jaguars,
0:14:11 > 0:14:14and he was, in fact, attacked by a cayman.
0:14:24 > 0:14:27It was just after the feeding.
0:14:27 > 0:14:29Sancho was playing
0:14:29 > 0:14:33and the cayman just came to him and bite his head.
0:14:33 > 0:14:38But in a few seconds, the cayman just...
0:14:38 > 0:14:43..let Sancho go and he was very afraid.
0:14:43 > 0:14:45He was scared about it.
0:14:45 > 0:14:49And after that, Sancho started to be scared
0:14:49 > 0:14:53of that place where he was attacked.
0:14:57 > 0:15:00Carolina has to help him get over his fear
0:15:00 > 0:15:03and encourage him back into the water.
0:15:06 > 0:15:08HE SQUEALS
0:15:08 > 0:15:10Her commitment to him is so strong,
0:15:10 > 0:15:15she finds herself drawn more and more into the giant otters' world.
0:15:20 > 0:15:23HE SQUEAKS
0:15:37 > 0:15:41When we are swimming, it's very funny when he approaches me
0:15:41 > 0:15:45and he starts playing with my feet and sometimes he bites me.
0:15:47 > 0:15:50I do believe he's really enjoying swimming
0:15:50 > 0:15:55and I can see it in his face, cos he shows that he's having fun.
0:15:58 > 0:16:02With huge webbed feet and a strong, flattened tail,
0:16:02 > 0:16:04Sancho is built for swimming.
0:16:04 > 0:16:08His instinct and ability are there, but he's still a little clumsy.
0:16:12 > 0:16:16It's very important to him we swim together, cos I think
0:16:16 > 0:16:21he's more confident to explore and search for new things underwater,
0:16:21 > 0:16:24cos, in the wild, he would probably be doing that now.
0:16:26 > 0:16:29Even though Carolina's research is on hold,
0:16:29 > 0:16:31she's learning more about giant otters
0:16:31 > 0:16:34than she could ever have imagined.
0:16:34 > 0:16:36I'd never dived with a giant otter,
0:16:36 > 0:16:40so Sancho is teaching me a lot of things about giant otters,
0:16:40 > 0:16:45the way they swim and the underwater behaviour.
0:16:46 > 0:16:49At the same time he's learning, I'm learning with him.
0:16:52 > 0:16:54I feel like my work is doing well
0:16:54 > 0:16:58cos his behaviour is just like a wild giant otter.
0:17:04 > 0:17:08I'm proud cos each day, I'm very pleased
0:17:08 > 0:17:11with his behaviour and his progress.
0:17:14 > 0:17:17Together, they have conquered Sancho's fear
0:17:17 > 0:17:20and he's now much more at home in the water.
0:17:24 > 0:17:27But Carolina knows he's still got a long way to go.
0:17:35 > 0:17:38Wild otter cubs gain their confidence
0:17:38 > 0:17:40by being at the very heart of the family.
0:17:48 > 0:17:50At the head is a dominant couple.
0:17:50 > 0:17:52Together for life, they are the parents
0:17:52 > 0:17:54of everyone else in the group.
0:17:58 > 0:18:00In the safety of such a large family,
0:18:00 > 0:18:03the cubs have plenty of time to play.
0:18:12 > 0:18:15They're also free from the pressures of finding their own food
0:18:15 > 0:18:19because every member of the family helps provide for them.
0:18:37 > 0:18:41Carolina has seen how a constant supply of live piranha
0:18:41 > 0:18:44is delivered to the cubs, while they wait on the bank.
0:19:02 > 0:19:05Everyone has a duty to help rear these cubs
0:19:05 > 0:19:08and teach them how to tackle their food.
0:19:22 > 0:19:25Carolina knows that somehow she is going to have to
0:19:25 > 0:19:27recreate this lesson for Sancho.
0:19:31 > 0:19:34She isn't just a surrogate mother to him now,
0:19:34 > 0:19:38she has to stand in for every missing member of his family.
0:19:42 > 0:19:46It's a tall order but Carolina is prepared to rise to the challenge.
0:19:47 > 0:19:51Every day means getting up at 5am to catch piranha.
0:20:02 > 0:20:06So far, Sancho hasn't shown any interest in catching his own fish.
0:20:08 > 0:20:12But now's the time for him to start to pull his own weight.
0:20:12 > 0:20:13Come, come, come, come, come.
0:20:17 > 0:20:20HE GROWLS
0:20:22 > 0:20:26In the wild, he will have to use all his senses to catch fish.
0:20:28 > 0:20:32And Carolina has decided that a paddling pool full of muddy water
0:20:32 > 0:20:36is the best way for him to get used to murky river conditions.
0:20:52 > 0:20:53Not only does this work,
0:20:53 > 0:20:57but some of his natural instincts are starting to kick in.
0:21:07 > 0:21:11He uses his whiskers to sense where the fish are.
0:21:13 > 0:21:14And when he's almost full,
0:21:14 > 0:21:17he tests himself further by playing with his food.
0:21:32 > 0:21:36Refining his skills like this seems to boost his confidence.
0:21:38 > 0:21:41But Sancho will need more fishing lessons
0:21:41 > 0:21:43before he's totally self-sufficient.
0:21:46 > 0:21:50The trouble is, the more Carolina prepares him for independence,
0:21:50 > 0:21:53the more attached she becomes to him.
0:21:55 > 0:21:59HE SQUEALS
0:21:59 > 0:22:01Ow!
0:22:18 > 0:22:23At six months old, Sancho is now totally at ease in the water
0:22:23 > 0:22:27and his natural curiosity is blossoming.
0:22:54 > 0:22:57Sancho is now more confident
0:22:57 > 0:23:01to spend more time diving and searching for things.
0:23:01 > 0:23:04He dives so deep.
0:23:04 > 0:23:08It's very nice to see him doing that.
0:23:11 > 0:23:14And he always comes back to me, just to check if I'm here.
0:23:14 > 0:23:21And, so, he feels safe to go out again and keep searching for things.
0:23:21 > 0:23:25But I have to be close to him, cos he's always checking.
0:23:27 > 0:23:30He's becoming much more aware of his surroundings,
0:23:30 > 0:23:32and, perhaps most importantly,
0:23:32 > 0:23:35he's started to take a keen interest in fish.
0:23:43 > 0:23:47Using his feet to steer and his tail for propulsion,
0:23:47 > 0:23:50he can now reach high speeds underwater,
0:23:50 > 0:23:53and has more chance of escaping his old enemies.
0:24:06 > 0:24:10But he still looks to Carolina for reassurance.
0:24:13 > 0:24:17She provides the protection he would expect from his family in the wild.
0:24:24 > 0:24:26Giant otters do everything together.
0:24:29 > 0:24:32Whenever they travel, the adults surround the cubs,
0:24:32 > 0:24:34always on the lookout for danger.
0:24:40 > 0:24:44Like Sancho, they are still vulnerable.
0:24:44 > 0:24:49And despite the family's care, only one in three cubs will survive.
0:24:54 > 0:24:57When the group finds fish, they begin to hunt.
0:25:00 > 0:25:02The chaos created by ten otters
0:25:02 > 0:25:06confuses the fish and makes them easier to catch.
0:25:13 > 0:25:15But it's each otter for itself,
0:25:15 > 0:25:17strictly hunting and eating alone.
0:25:20 > 0:25:24The cubs pester the grown-ups and constantly call for food.
0:25:31 > 0:25:34CUB SQUEAKS
0:25:42 > 0:25:46The adults eat first before tending to the youngsters.
0:25:46 > 0:25:49Then they offer smaller fish
0:25:49 > 0:25:52and encourage the cubs to play with and chase them.
0:25:52 > 0:25:55All good practice for tackling their own slippery prey.
0:26:05 > 0:26:07On each fishing trip,
0:26:07 > 0:26:11the cubs must learn an enormous amount from the adults.
0:26:11 > 0:26:13But this is where Carolina's abilities
0:26:13 > 0:26:17as an otter mother reach their natural limit.
0:26:17 > 0:26:19She can only guess how young otters
0:26:19 > 0:26:22learn to hunt from what she's witnessed at the surface.
0:26:25 > 0:26:30Somehow, she's got to encourage Sancho to catch his own food.
0:26:30 > 0:26:32And this is proving to be the trickiest part
0:26:32 > 0:26:34of his rehabilitation so far.
0:26:37 > 0:26:39Carolina has had to think long and hard
0:26:39 > 0:26:42about a training programme for Sancho.
0:26:43 > 0:26:46But, in the end, it's down to trial and error.
0:27:35 > 0:27:39This is going to take a lot of practise.
0:28:08 > 0:28:11Once he starts to fish by himself,
0:28:11 > 0:28:15I will start to...break the bond he has with me
0:28:15 > 0:28:17and that will be hard as well.
0:28:19 > 0:28:26At the same time, I really want him to go and become a wild giant otter,
0:28:26 > 0:28:28but when this moment comes,
0:28:28 > 0:28:32I'll be proud of that, but, for sure, I will miss him.
0:28:33 > 0:28:36Bringing up Sancho hasn't been easy,
0:28:36 > 0:28:38but Carolina is beginning to realise
0:28:38 > 0:28:40that the hardest part is yet to come.
0:28:41 > 0:28:44She is going to have to let him go,
0:28:44 > 0:28:47and the moment of separation is edging ever closer.
0:28:58 > 0:29:02The rains have stopped and the Pantanal is drying out.
0:29:06 > 0:29:10As the water levels fall, fish become trapped.
0:29:17 > 0:29:20Life gets easy for abundant water birds.
0:29:35 > 0:29:38But birds aren't the only ones to take advantage
0:29:38 > 0:29:40of the glut of easy food.
0:29:47 > 0:29:50It's a perfect time for Sancho to head off on his own,
0:29:50 > 0:29:53but Carolina still has to think carefully
0:29:53 > 0:29:55about where she can release him.
0:29:57 > 0:30:01Wild giant otters are aggressively territorial.
0:30:02 > 0:30:06Their home ranges can be over 12 miles
0:30:06 > 0:30:08and they patrol them constantly.
0:30:08 > 0:30:12The giant otters have different ways to mark their territory.
0:30:12 > 0:30:17They can use the smell, scent glands and visual marking.
0:30:17 > 0:30:20They scratch the river bank.
0:30:21 > 0:30:24And sometimes they use their voice to mark that place.
0:30:26 > 0:30:30These are clear signs to all other otters that this land is taken.
0:30:32 > 0:30:35They have a special care with the scent marking
0:30:35 > 0:30:39because it's very important to keep their territory
0:30:39 > 0:30:42and avoid fights with other giant otters.
0:30:47 > 0:30:51Carolina hopes that there is room here for one more otter.
0:30:51 > 0:30:56But she has no idea whether a close-knit family like this
0:30:56 > 0:30:58would accept him or kill him.
0:31:04 > 0:31:06If Sancho enters into another group territory,
0:31:06 > 0:31:11the group may not accept Sancho and have a fight.
0:31:11 > 0:31:14So...it's so important for me
0:31:14 > 0:31:18to know the groups and their territory in this area.
0:31:18 > 0:31:21CUBS SQUEAL AND CALL
0:31:21 > 0:31:24This is going to be a tense time for Carolina.
0:31:24 > 0:31:27She can point Sancho in the right direction, but ultimately,
0:31:27 > 0:31:32it will be up to him to find and defend his own territory.
0:31:43 > 0:31:47Sancho is now eight months old and Carolina thinks she has found
0:31:47 > 0:31:51a stretch of no-man's land fit for his fresh start in the wild.
0:32:05 > 0:32:07She continues to help him fish,
0:32:07 > 0:32:11but she knows this is the beginning of the end of motherhood.
0:32:11 > 0:32:14SANCHO SQUEALS
0:32:19 > 0:32:23I decided to move Sancho in order to break the human contact
0:32:23 > 0:32:28and show him another territory for him to start to explore.
0:32:28 > 0:32:30In the first few days,
0:32:30 > 0:32:32he was not confident to travel further,
0:32:32 > 0:32:40but now, I can see that he's showing more interest in exploring new places
0:32:40 > 0:32:43and he's spending more time on his own, which is good.
0:32:45 > 0:32:48HE SQUEALS
0:33:05 > 0:33:08Despite the great strides he has made, Sancho is still young
0:33:08 > 0:33:12and Carolina knows she will always worry about him.
0:33:17 > 0:33:19But the mothering will have to stop,
0:33:19 > 0:33:22if Sancho is ever going to be self-reliant.
0:33:41 > 0:33:44She decides to leave him for most of the day
0:33:44 > 0:33:48in the hope that he will start searching for his own food.
0:33:52 > 0:33:54This really is tough love.
0:33:57 > 0:34:00For the first time, Sancho is on his own.
0:34:05 > 0:34:08SANCHO SQUEALS
0:34:08 > 0:34:13I'm not sure that Sancho is 100% able to defend himself.
0:34:13 > 0:34:15When he's by himself,
0:34:15 > 0:34:18he shows that he's not comfortable,
0:34:18 > 0:34:22and he spends some time calling his mother.
0:34:23 > 0:34:26So, I don't believe he feels safe all the time.
0:34:26 > 0:34:29SANCHO SQUEALS
0:34:29 > 0:34:31He cries for Carolina constantly.
0:34:32 > 0:34:35Something no wild otter would do,
0:34:35 > 0:34:37as it could attract unwanted attention.
0:34:37 > 0:34:39HIGH-PITCHED SQUEAL
0:34:47 > 0:34:51Unwittingly, he has called in a pair of wild otters.
0:34:58 > 0:35:01OTTER SNORTS
0:35:03 > 0:35:06Sancho has never seen another giant otter before
0:35:06 > 0:35:08and has no idea how to react.
0:35:10 > 0:35:13On the first day, Sancho was a little bit afraid of the couple
0:35:13 > 0:35:18and he stayed most part of the time close to me, just watching.
0:35:37 > 0:35:39HE SQUEALS
0:35:41 > 0:35:42It's a new experience for Sancho.
0:35:42 > 0:35:45At the same time he's losing human contact,
0:35:45 > 0:35:48I think it will be very stimulating for him.
0:35:48 > 0:35:53Maybe it will help him to...
0:35:53 > 0:35:57..finally find his way.
0:36:02 > 0:36:04Over the next few weeks,
0:36:04 > 0:36:08Carolina watches as the couple visit Sancho regularly.
0:36:37 > 0:36:41His initial nervousness begins to dwindle
0:36:41 > 0:36:44as he realises he speaks their language.
0:36:46 > 0:36:49OTTERS SQUEAK
0:36:59 > 0:37:02Luckily for Sancho, this couple seems friendly.
0:37:04 > 0:37:07In fact, their meetings help to build his confidence.
0:37:11 > 0:37:15All of a sudden, Sancho seems ready to take the final plunge
0:37:15 > 0:37:17into the giant otters' world.
0:37:49 > 0:37:52Carolina starts to reduce his fish rations.
0:37:54 > 0:37:58Until one day, she discovers he doesn't need her any more.
0:37:59 > 0:38:02SANCHO SCREAMS
0:38:06 > 0:38:08We just found him eating a big fish,
0:38:08 > 0:38:12so, we realised that he'd just caught his first fish.
0:38:12 > 0:38:16Actually, I think he was already catching his own fish
0:38:16 > 0:38:18but hiding from us.
0:38:20 > 0:38:23It's great and after this day, he's started to fish
0:38:23 > 0:38:26almost every single day.
0:38:30 > 0:38:33Sancho has finally proved he can look after himself.
0:38:42 > 0:38:44Torn between pride and sorrow,
0:38:44 > 0:38:48Carolina seeks solace in her role as a researcher.
0:38:50 > 0:38:54There's a lack of information about this period of giant otters' lives -
0:38:54 > 0:38:56when they leave the family
0:38:56 > 0:39:00and start to travel to find a mate and a territory.
0:39:00 > 0:39:04So, I think Sancho will be very important
0:39:04 > 0:39:07and he will give us a lot of information about this period.
0:39:11 > 0:39:13Although the separation will be hard for her,
0:39:13 > 0:39:17Carolina's confident she will continue to learn from him.
0:39:30 > 0:39:34But then, the moment every mother dreads.
0:39:44 > 0:39:48SHE CALLS: Come, come, come, come, come, come, come, come.
0:39:50 > 0:39:52Come, come, come.
0:39:56 > 0:39:58Come, come, come.
0:40:05 > 0:40:11I've arrived here this morning and Sancho was not here.
0:40:28 > 0:40:35He hasn't travelled far from here and...that's why I am concerned,
0:40:35 > 0:40:40cos what happened to him to just decide to go away,
0:40:40 > 0:40:43if he doesn't know this place?
0:40:46 > 0:40:50It could be that Sancho has grown up quicker than Carolina realises.
0:40:53 > 0:40:56Come, come, come, come, come, come, come, come.
0:40:56 > 0:40:57In the wild,
0:40:57 > 0:41:01giant otter cubs do become independent at nine months old.
0:41:01 > 0:41:03But they're still at risk.
0:41:05 > 0:41:09I think he is still potential prey for cayman, a big cayman.
0:41:10 > 0:41:12And if...
0:41:12 > 0:41:18..if he was sleeping on the ground, he was potential prey for a jaguar.
0:41:24 > 0:41:26I have to look for him.
0:41:26 > 0:41:30So, I'll take the canoe and...
0:41:30 > 0:41:32..and try to find...
0:41:32 > 0:41:38..try to go to the places I have already been with him.
0:41:38 > 0:41:40And...
0:41:40 > 0:41:42Unfortunately, I have to look for, erm...
0:41:50 > 0:41:54SHE SOBS
0:41:54 > 0:41:59I have to say that I have to look for his body,
0:41:59 > 0:42:06in case...he was killed by any animal.
0:42:06 > 0:42:08I have to do this,
0:42:10 > 0:42:14but I'm still thinking positive about it.
0:42:18 > 0:42:20He's just a rebel.
0:42:20 > 0:42:22Maybe he's trying to...
0:42:26 > 0:42:30..show he's angry about us
0:42:30 > 0:42:33leaving him alone for a long time,
0:42:33 > 0:42:37or giving him less food, I don't know.
0:42:37 > 0:42:40But I'm still thinking he'll come back, soon.
0:42:46 > 0:42:48Come, come, come, come, come.
0:42:50 > 0:42:53Come, come, come, come, come. Sancho?
0:43:00 > 0:43:02Sancho?
0:43:07 > 0:43:10Come, come, come, come, come, come, come.
0:43:14 > 0:43:17Come, come, come, come, come, come, come.
0:43:17 > 0:43:19Sancho?
0:43:20 > 0:43:23Come, come, come, come, come, come, come.
0:43:23 > 0:43:26Sancho?
0:43:34 > 0:43:38Three months have now passed since Carolina last saw Sancho.
0:43:41 > 0:43:43He's left a huge hole in her life.
0:43:48 > 0:43:52She has found some comfort in resuming her research project,
0:43:52 > 0:43:55even though she spends a lot of time looking for him.
0:44:02 > 0:44:06But Sancho has left her with more than just memories.
0:44:13 > 0:44:17Wild otters are normally very shy and difficult to get close to.
0:44:19 > 0:44:22But this is the pair that Sancho befriended all those months ago.
0:44:31 > 0:44:35So used to seeing her with Sancho, they have accepted her.
0:44:36 > 0:44:39She is rewarded with an exceptional front row seat.
0:44:39 > 0:44:41OTTER SQUEAKS
0:45:10 > 0:45:15She's trusted enough to have a rare glimpse of their newborn cubs.
0:45:27 > 0:45:29I'm monitoring this couple
0:45:29 > 0:45:32since they started visiting Sancho a few months ago,
0:45:32 > 0:45:34and I'm following all the process
0:45:34 > 0:45:38since they copulated and showed the first signs of pregnancy.
0:45:38 > 0:45:41So, seeing them now with the cubs is very special.
0:45:41 > 0:45:47I feel like part of their family and I am very happy to know that
0:45:47 > 0:45:50they are living fine here.
0:45:54 > 0:45:58Deep down, Carolina hoped that Sancho might have joined forces
0:45:58 > 0:46:01with this young couple.
0:46:02 > 0:46:04Evidently, that was not to be.
0:46:09 > 0:46:12But Sancho gave Carolina a real insight,
0:46:12 > 0:46:16a deeper understanding of what it actually takes to be an otter.
0:46:18 > 0:46:22Seeing cubs reminds me of Sancho all the time,
0:46:22 > 0:46:27and I'm glad in seeing in these cubs the same behaviour I saw in Sancho.
0:46:27 > 0:46:29The whole process with Sancho
0:46:29 > 0:46:32is helping me now to understand what's going on here.
0:46:36 > 0:46:40Carolina's relationship with Sancho also changed her life.
0:46:45 > 0:46:48Raising Sancho was a special experience in my life.
0:46:48 > 0:46:54Being in touch with such a beautiful and lovely animal was amazing,
0:46:54 > 0:46:57and at the same time challenging.
0:46:57 > 0:46:59And I tried to teach Sancho lots of things
0:46:59 > 0:47:02but I'm sure I learned much more from him,
0:47:02 > 0:47:06and now all these things I learned are helping me to understand
0:47:06 > 0:47:08the cubs' behaviour in nature.
0:47:11 > 0:47:14Carolina did everything she could for Sancho,
0:47:14 > 0:47:17but she still doesn't know if it was enough.
0:47:20 > 0:47:23Perhaps the hardest part for Carolina is the not knowing.
0:47:25 > 0:47:28But now, as she travels the waterways of the Pantanal,
0:47:28 > 0:47:31her research has an extra dimension,
0:47:31 > 0:47:36a glimmer of hope that he could be out there, somewhere.
0:47:36 > 0:47:41I have now one special reason to keep my monitoring work.
0:47:41 > 0:47:44I have to look for Sancho and I'm sure, one day,
0:47:44 > 0:47:47I will find him with his family.
0:48:04 > 0:48:08Next week, Natural World goes on a spiritual journey,
0:48:08 > 0:48:15spending a year exploring the wildlife of the moors, woodlands and rivers of Dartmoor
0:48:15 > 0:48:21with Satish Kumar, ecologist, former Jain monk, and pilgrim for peace.
0:48:27 > 0:48:29Subtitles by Red Bee Media Ltd
0:48:29 > 0:48:32E-mail subtitling@bbc.co.uk