Natural World (1983) s28e04 Episode Script
Crocodile Blues
1 The gharial is the world's oldest crocodilian.
It evolved before the dinosaurs and at the peak of its range, it thrived in rivers from Spain to Japan.
At 20 feet long and a tonne in weight, it is the ultimate fish-eating crocodile, and one of evolution's most successful species.
BABY GHARIALS SQUEAK The gharial's continued existence on the planet is owed in part to one man - Romulus Whitaker.
In the 1970s, Rom and his colleagues brought the gharial back from the very edge of extinction, and they have spent the past 30 years fighting to re-establish this crocodile and protect its ever-dwindling habitat.
They were making slow, but steady progress, until last winter, when a mysterious and unprecedented mass die-off brought this giant reptile to its knees.
Is Rom about to witness the first extinction of a crocodilian in human history? Or can he and his team save this mighty creature from this current crisis? This is the story of a crocodile which, after 150 million years of existence, has been reduced to less than 200 breeding animals.
HE PLAYS BLUES I can remember the time I saw my first live gharial.
The first time I ever picked one up.
I think my sense of amazement for this creature just hasn't changed, hasn't diminished a bit.
It is just a too much animal.
GHARIAL GROWLS As a child, Rom moved to India with his family.
In this wildlife wonderland, he developed a passion for all things reptilian.
Enthralled by snakes and captivated by crocodiles, he made them his life's work, and 60 years on, he is a living legend in the worlds of herpetology and conservation.
But the animal that has cast the greatest spell over him is India's iconic crocodile, the gharial.
Evolution has tuned this thing to be the most efficient fish catcher, the best river crocodile the universe has ever produced.
The gharial is perfectly adapted to its aquatic habitat.
Powered by its muscular tail, its webbed feet and natural goggles make it a swimming machine.
It's able to control its specific gravity by shifting its internal organs, rising and falling at will.
And its slender snout with razor-sharp teeth is the ultimate fish-catching tool.
But the gharial's extreme specialisations make it uniquely vulnerable.
The gharial is just so finely tuned, and so closely linked to its river habitat, that if anything goes wrong, the gharial would be like a fish out of water.
When Rom conducted India's first croc surveys in the 1970s, he found that there were less than ten adult males surviving in the wild.
With habitat conservation and a restocking programme, by 2006, total population numbers had increased to over 1,000.
But in December 2007, the recovering gharial were dealt a devastating blow.
OK, lots means how many gharial are dead? No, there's something very, very serious going on here.
I'll get up there as soon as I can.
This has gotta happen now, it's very, very urgent.
The Chambal River Sanctuary in northern India is home to nearly half of the world's population of wild gharial.
But as Rom had learnt, 10% of this vital population has died in sudden and mysterious circumstances.
I'm fearing the worst, because this is really a case of all your apples in one basket.
If something is wiping out the gharial and it's contagious, or it's something irreversible, then I don't know where it's gonna end.
And no sooner has Rom arrived than another dead gharial has washed up, bringing the death toll to 90.
It's a devastating scene.
But Rom's emotions must be put on hold, as Rom the scientist takes over.
This is basicallyan adult female.
In a way the most important segment or sector of the population is the females, who lay the eggs and populate the river, so We're gonna try to learn as much as we can from this loss.
News of the disaster has rippled across the world.
A major species is on the brink.
Emergency response teams have been dispatched to the Chambal, and Rom has joined a group of Indian and international vets.
They set to work with an impromptu autopsy on the banks of the river.
The colour of the flesh is normal and it's very fresh.
The autopsy is vital to discover what killed this gharial, and may provide clues as to what's causing the larger die-off.
This animal has literally just died.
I mean, we're talking about earlier this morning.
That means it's in a good state of preservation, you know? At this stage in the examination you don't try to interpret everything you see, you're just trying to make sure you don't miss anything in the picture, so then you can see if the pieces makes sense, so you make sure you describe each piece at this stage.
You don't find something and say, "This is a sign of that disease".
The vets address each of the organs in turn.
The lungs show no obvious signs of damage, but the team is particularly interested in the joints and kidneys, which show an unusual build-up of a powdery white substance.
The team have gathered as many clues as they can from this specimen.
I don't know what anyone else has learned about this, but I've learned a heck of a lot, because the previous animals looked at were all quite rotten already, and a lot of the organs had either dissolved, or were discoloured.
But I think the major thing that we're gonna learn out of this is what the veterinary doctors come up with.
This is really a grim scenario.
My colleagues and I have worked on rivers like the Chambal since the 70s and these are animals so close to our hearts.
I think we're trying to deal with the situation, the tragedy of it, probably the same way you deal with it on the front line when a war's going on.
It's that bad.
This is the time when all the birds go home.
As the team head home too, Rom is wondering whether there are any more clues as to the cause of the disaster elsewhere in the area surrounding the river.
Back in the 1970s, we did some of the first crocodile surveys and found that the Chambal, one of the wildest rivers left in India, still had some gharial, and sure enough it turned out to be ultimately the place where the release programme was started, and in 1979, the government formed the National Chambal Sanctuary to protect this fantastic river stretch of over 400 kilometres, and now it does have the largest population of gharial in the world.
It is not just conservation laws that have preserved the sanctity of this landscape.
These wild Chambal ravines used to be the hide-out of really famous bandits, dacoits called Makhan Singh .
.
and Man Singh and the famous bandit queen, Phoolan Devi.
Their days are over, but the place is still wild, it's still a dangerous place.
There are still some dangerous folks around.
But what it's done for the Chambal river is actually protected the place, because people just were scared to come here.
That's probably one reason why the gharial has survived here, and nowhere else.
Where bandits once prowled, it is now down to Rom and his colleagues to protect the gharial and its river.
And it seems the perils are now more complicated than population pressure alone.
The Chambal may feel like a pristine wilderness, but somewhere in the river lurks the menace that's decimating its most precious inhabitant.
The next morning finds the vets hard at work, carrying out another autopsy, this time on a baby gharial.
Working in their hotel bathroom, they are weighing up three possible causes of death - poisoning, parasites and infection.
But they need to compare their samples with those from a healthy living gharial.
So Rom and the team head back to the river.
Helping to co-ordinate the operation is one of India's leading environmentalists, Kartick Satyanarayan.
Take the entire kit, dog catcher, everything.
So that's the net they brought last night.
Yeah.
This is the one Dibulal got? Yeah, but we've got a back-up net here too, a huge one, which Basu got.
OK.
And we have a third net, which came from Agra.
I don't think we're taking any chances.
If we need something we'll call for you.
They do say that too many cooks spoil the soup.
In this case, everyone's essential.
An operation like this, if it's not well planned, obviously it's not gonna succeed, so it's worth all this banter and backing and forthing to make sure we've all got it straight.
Let's go.
I love it when someone just says the right word and everyone starts moving! Good.
Thanks, Kartick! Fantastic.
And we get in here.
OK.
Come on, let's go.
To catch at least one live healthy gharial is very important for the vet doctors because they need to check the blood, and you can't take blood out of a dead gharial, the blood congeals.
So we very much need a live gharial.
Although the Chambal River Sanctuary is 250 miles long, the affected gharial have all come from a 25-mile stretch.
It also appears that only a certain size class of animals is being affected.
Adding to the mystery is the fact that other river reptiles, like the mugger crocodile and soft-shell turtles, appear to be in robust health.
And birds that share the gharial's diet also seem to be unaffected.
We're looking at a fish-eating bird and they've got the same food chain as the gharial has, so if the gharial is being affected by something in the fish, in the food chain, why aren't the birds? But while Rom is busy mulling over the mystery, Kartick has got to work.
And in one of the many nets, he's landed the catch of the day and brought a smile to Rom's face.
Kartick! Oh, man, she's gorgeous.
Fantastic, man.
This is so good, man.
Oh, she's beautiful.
She's beautiful.
Absolutely.
GHARIAL GROWLS Mmmm! Yeah, I feel the way you do.
She's talking.
Don't worry, you won't be out for long.
So fortuitous because the doctors are arriving at the same time, so we've got all the experts and now we'll be able to get a blood sample.
This looks like a good place.
'I think that went incredibly well.
'First of all, the odds of us catching a live gharial 'within a few hours of trying, 'and we got it right within the size class 'of the animals which are dying in the Chambal, 'the foreign vets, they got samples of blood, 'cells from the liver, 'they got a bit of gastric content, in other words the stomach contents.
'There is a bit of pain when the needle goes into the skin, 'because it does have nerves, just like any of us getting an injection, 'but he didn't really struggle.
' The point is we're trying to find the source of this problem, and for one gharial to suffer for a few minutes a bit of pain, I think is really necessary at this point because we're trying to get to the bottom of the major die-off, which has never happened to any crocodilian that we know of.
Scientists and ecologists fear that we are on the brink of multiple extinctions, as ecosystems around the world collapse.
Could the mysterious die-off of gharial be a foreshadowing of some larger cataclysmic event? OK, this is a very sacred moment.
We've got to remember that gharial are able to turn around almost completely And as another of our most endangered animals is brought to the brink, is the world finally ready to sit up and take notice? Wow! Fantastic, eh? Fantastic.
Ah! While Rom is waiting for the vets to report their findings, he heads back south to Chennai and the Madras Crocodile Bank.
This is the centre he established in 1976 for the captive breeding of India's endangered crocodiles.
Over the years it has bred thousands of animals for release into the wild.
It's now an internationally renowned research centre and educational facility, and headquarters for Rom's conservation work.
Croc Bank is really the base of all our conservation operations on crocodilians in India.
Whatever we've learned about crocodilians, this is the repository.
This is where we start out on all our fieldwork, and this is where we end up when we come home.
Over three decades, Rom has built up the Croc Bank's gharial population.
It's an insurance policy against their decline in the wild.
The Chambal die-off has reduced wild breeding numbers to below 200.
Rom's efforts here are suddenly key to the survival of the species.
In the 1970s, the Croc Bank inherited its first four gharial.
There are now 13 adults and these are the two sexually mature males.
At the start of the annual breeding cycle, each attempts to assert its dominance over the other.
This is the height of the mating season, and we get to see some incredible stuff here in the gharial breeding pit.
This is the time of year when one adult male tries to outdo the other one and chase him out.
It can't get out of here, so sometimes massive fights ensue.
The males might work out their own pecking order, but it was up to Rom to perfect the art of breeding them.
Back in the 70s, we didn't really have a clue how to breed them in captivity.
They'd never bred in captivity before.
What was critical and pretty obvious, from the beginning, was that we had to have adult animals and it took 13 years before the gharial finally grew his ghara, on the tip of his snout, and we realised, OK, now it's the time.
The ghara, which gives the gharial its name, is a lump of cartilage which grows on the snout of mature males, and plays a key role in attracting a mate.
Their real method of attracting the females is doing something we call a buzz-snort.
It kind of goes like prr-rr-rrrp.
It sounds very impolite, but it seems to be very effective and it's created by the fact that the ghara of the male, sitting on top of its nostrils, sort of modifies the sound of its hissing into this very, very weird, but effective way of attracting females.
When they finally did start breeding, it was an amazing day for us.
The first clutch of eggs, I think it was just 12 eggs, and virtually every one of those eggs hatched, so we knew we were doing something right.
What Rom and his team achieved in the 1970s was vital for the future of the species.
It was extremely important for us to breed the gharial in captivity, at that stage.
It was down to 200 in the wild.
These things were really endangered so it was critical that we got them to breed in captivity.
Rom's captive-bred gharials have been released into the wild in two locations - on the Chambal, and at a sanctuary on the River Girwa called Katernia Ghat.
Rom needs to make sure that the Chambal's devastating die-off hasn't taken hold in this second sanctuary, so he's travelled to Katernia Ghat to see for himself.
For Rom, it's like coming home.
This is Katernia Ghat.
We've got 15-20 kilometres of pristine river.
We've got gharial, we've got mugger, bird-life I'd call it one of the best-kept secrets in India, really.
The Garden of Eden for one of my favourite animals, the gharial.
But all the other life here too.
It is totally amazing.
Rom's first task is to travel the length of the protected area and carry out a census, checking on the numbers and health of the Katernia Ghat's gharial.
'It's just incredible to think what's going on in the Chambal right now 'and gharial just dying like flies, 'but it's even more important that a place like Katernia Ghat 'is secure for gharial.
' In 2006 there were some 60 adult gharial living in the Katernia Ghat Sanctuary.
Rom's hoping that this population has at least remained stable.
That's a big gharial.
A preliminary tour has revealed about 30 gharial and thankfully these animals are all in good health.
I would say here is a secure population, and as a back-up to the Chambal population, it's now become more and more important to make sure that this stays intact.
But Katernia Ghat is minute, and Rom's "secure population" has little more than three miles of ideal habitat in which to live.
You have to look at it in a global perspective.
You've got probably 25% of the entire breeding population of gharial in the entire world right here, in a little chunk of habitat, with no protection below and no protection above, so it's very finite and it's very fragile.
And although these gharial are free from the mystery die-off, they are beset on all sides by other pressures that may prove to be just as deadly.
Even right in the sanctuary here there are several villages, people living here.
This is a very, very packed state, the state of Uttar Pradesh.
Population pressures are everywhere.
A major threat to the wildlife at Katernia Ghat is fishing.
Illegal in the sanctuary itself, it happens right up to its borders both up and downstream.
Subsistence fishermen and gharial have long competed for the same catch, but today's contract fishermen and monofilament nets give people an unfair advantage, and have an unfortunate side effect for the gharial.
Downstream outside of the sanctuary, fishing is a big thing, and you can see the prey base for gharial is perfect here, but the trouble is, if gharial start messing around in this, they get their teeth caught in it and they get twisted up, and they might even drown.
This is a big problem.
Luckily, they've sorted it out inside the sanctuary, but a gharial doesn't know where the sanctuary boundaries are, he comes downstream and gets caught, it's a very, very bad business for a gharial.
The threats to Katernia Ghat's gharial are obvious to Rom, but the cause of the die-off elsewhere remains a mystery.
Speculation about infectious disease and parasites is rife, but the vets are concentrating on poisoning through the food chain.
Another Indian animal that might hold a clue to the gharials' fate is the vulture.
It shares a diet with many of India's scavengers.
Where the rest of these scavengers go from strength to strength, vultures alone are circling towards extinction.
The reason why it's such a pleasure to see these vultures up here is because in the last ten years we've lost maybe even more than 90% of India's vultures, because of a specific drug called diclofenac.
It's a simple drug given by farmers to their cattle to reduce pain, but it's something that attacks the kidneys of the vulture, and they die very, very quickly.
Rom suspects something similar may be causing the mass gharial die-off, and that whatever is killing the gharial in the Chambal may also be specific to just that species.
But for the moment it seems that the gharial at Katernia Ghat are at least safe from the die-off.
And that evening, as Rom returns, the sanctuary is about to play host to a remarkable spectacle.
For over 150 million years, gharial have nested on riverbanks.
But now, in one of their last strongholds, they are reduced to nesting on just one sandbank.
And Rom may be about to witness one of the last times this ever happens.
It's It's getting close to sunset.
I'm kinda surprised, but it looks like one of the gharial is starting to climb the bank.
From here, anyway, it looks like she's full-bellied, full of egg.
She goes up in a jerky way, it's a very steep bank WHISPERS: It's a very steep bank.
I don't wanna disturb her! And they've got rather weak legs, strong for swimming, but weak for climbing up on land, so she sort of humps her way up the slope.
But there are other gharial interested in this particular sandbank.
Females that have already nested are watching proceedings as closely as Rom.
There's another one coming up, a larger one.
She looks slimmer.
Looks like she has already laid her eggs, and she's a little worried about that one digging up top.
This is her defensive mood.
It doesn't matter that it's another gharial, it's somebody digging.
I don't think she likes it.
There's a very good chance that one of them will scoop out the eggs of the previous nester.
There's definitely an urge to protect their own nest site.
As the camera struggles with the fading light, more gharial arrive.
The island is getting crowded, and dominant females begin to compete for the prime sites at the top of the sandbank.
Both of the big females are knocking their beaks together.
They're trying to sort out who's boss here.
This is really I've never seen this before, but it's obvious that the females are defending their nest site, even from other females, so there is some sort of pecking order, some hierarchy going on.
And this is a tiny sandbank so it really is just not enough space for all these animals, which is one obvious reason why this is happening.
But the gharial aren't just competing with each other for the prime nesting sites, they also need to see off the threat of a mugger crocodile, who is equally interested in the high sandbank.
The dominant females are distracted, leaving an opportunity at the other end of the island.
The smaller one is now on top.
She's starting to scrape sand with her legs.
I can actually see, even without the binocs, sand flying through the air.
The gharial uses its powerful rear legs and webbed feet to excavate a nest pit as deep as its legs are long.
Yeah, she's starting to dig down inside.
Now you start seeing different colour sand coming out.
It was dry sand at first.
That dark stuff is the damp sand from inside so she's making her hole now.
In a scene that has never before been documented, the island has become a busy maternity ward, as more gharial arrive and stake their claim to a precious patch of sand.
They too begin their timeless nesting ritual, a process that will last well into the night.
It's getting very dark.
I can just barely see what's going on.
There's definitely a couple of them laying though.
Good luck to them.
Each gharial will lay up to 50 eggs, which will incubate for 70 to 80 days and hatch just before the onset of the monsoon.
Next morning, and the nesting frenzy is over, leaving the island covered with the scars of last night's laying activity.
Amazed by the overcrowding on the tiny sandbank, Rom and forest guard Ramrup head over to count the freshly dug nests.
Using a wire rod to gently probe the sand, they find six freshly laid nests, bringing the total on this island to a very crowded 24.
It's totally amazing, and we're probably looking at maybe even a quarter of the entire nesting effort of all of the world's wild gharial on this little tiny spit of land that's like, what, about 40 metres long, 20 metres wide.
It's a tiny place, totally vulnerable to the monsoon floods, but the vast majority of the gharial in the Girwa are laying their eggs right here, and we've noticed that some nests, I mean, some of the nesters, have dug out other nests and there are a couple of eggs lying around, so this is very limited, and it's very worrisome too, because what'll happen when another monsoon comes? Look at this steep embankment on this side.
Come over and check this out.
Another steep embankment on this side.
It's so obvious the gharial prefer this.
They want to climb up on to something high.
That really makes sense in every sense of the word, because this river does rise very fast, and if it rose unseasonably early, all the eggs would be submerged and drown.
Rom hopes his worst fears won't be realised, because this small island seems to be the only nesting place for gharial in the entire sanctuary.
It's a precarious scenario for an already endangered species.
Just a few miles downstream is a potent vision of why, today, there are so few gharial nesting sites.
Where for millions of years they happily excavated their sandy nests, India is now extracting building sand on an epic scale.
Sand mining.
Sand mining in river beds.
I mean, we've got to have sand.
India is growing.
Growing, growing, growing.
Building more houses.
Construction.
Everything.
But mining it from a riverbed is no good.
It's no good for the hydrology and it's certainly no good for gharial.
Gharial lose their basking spots, they lose their nesting spots.
Same for turtles.
It's just bad all round.
Although this riverbed looks like a desert, it wasn't long ago that this was prime gharial habitat.
Every river bed in India is getting drier and drier every year and this isn't natural.
We're just taking the water for irrigation, we're damming it, we're barraging it, we're canalling it.
We're doing everything to get water to other places for agriculture.
Needed stuff, but needed - sure - it's got to be done sensibly, too.
We've got to remember, we're looking after gharial too, OK? Back at the Croc Bank, the most successful enclosure emulates the steep sandbanks at Katernia Ghat.
And while Rom has been away, his prize female Roxanne has laid her annual clutch of eggs.
This is the spot, right, where they marked it? Although this sandbank may be perfect for Roxanne to nest, conditions here in India's deep south are too hot for successful incubation.
So the eggs need to be excavated to ensure that they will hatch.
The reason why he's got a stick in his hand is because they are defensive with their nests.
Nothing like a saltwater crocodile or a mugger, but Nonetheless, they do have sharp teeth, and they really don't like the idea of you stealing their eggs.
It's not just Roxanne who's upset by Rom's nest raiding.
The dominant male, too, is taking an unhealthy interest in proceedings He's a big guy and a little scarier than the females, so we just have to be a little careful here! Because you know, when you get concentrated on your work, you just forget that there's some toothy little creature behind you.
It's very important to mark the orientation of each egg, because if you turn the egg over, you can actually kill the embryo.
In the present context of the gharial being critically endangered and the die-off that's happening in the Chambal, captive breeding programmes like this become more and more important.
And it's really critical that we have this repository of captive animals, you know, as a safety measure.
We're hoping like hell that the gharial doesn't go extinct in the wild, but nonetheless, this the back-up, this is the insurance policy.
46, 47and one last one.
That's the largest clutch size we've ever had at Madras Crocodile Bank for the gharial.
That's amazing.
48 eggs.
Thanks, Roxanne! OK, let's get the eggs up, we're gonna incubate them.
Basically, what we have to do here is candle the eggs because that determines whether the eggs are fertile or not and Nikhil is an expert at this, but to be able to do it, we have to switch the lights off.
OK, let's see what we've got.
This moving dark horizontal line shows that the egg is viable.
The black spot at the top of the egg is called banding and grows as the embryo continues to develop.
So, the embryo always attaches itself to the top.
Most of the time.
We're calling that a fertile one, right? We always used to say, "Treat the eggs like nitroglycerine.
" Easy, easy, don't roll them! Don't let them explode.
Oh, that's nice.
With his precious clutch safely under wraps, Rom has returned to the Chambal, site of the winter die-off, to follow up on the mystery.
With the arrival of warmer weather, the gharial deaths appear to have stopped, and through study of their autopsy samples, the vets may have reached a breakthrough.
They have discovered that the white powder observed on the gharials' organs is crystallised uric acid.
Uric acid is not very soluble, and at a certain level it reaches saturation.
When it reaches saturation, it crystallises out.
OK.
The amount of uric acid in the blood is controlled by the kidneys, and when levels are this high, it points to kidney failures.
Kidneys are an essential organ in gharial, just like they are in any animal.
When uric acid builds up in the joints it causes gout, a debilitating condition, that in a reptile can be deadly.
An animal with this kind of thing cannot move its limbs anymore.
So they come along, go up to the sandbank too fast, and very often they cannot even control their swimming, because they need their hands and feet for balancing.
Wow.
That makes it even sadder in a way, doesn't it? It does, yes, yes.
Very sad.
Filmed during the die-off, these images show the death throes of a gharial crippled by agonising gout.
The winter's record low temperatures on the Chambal, may also have played a part in this disaster.
The solubility of uric acid varies by temperature, so the cold temperature certainly could play a role into the manifestation of disease in this instance.
Death is unavoidable.
The vets believe that the die-off was caused by gout, brought on by a combination of cold weather and kidney failure, and that the kidney failure itself was caused by poisoning.
It must be a toxin.
It must be something toxic in the water or in the fish or something that they're eating.
They've got a toxin in them somehow.
It seems that Rom's vulture hunch was right, and that the Chambal gharial have been poisoned.
We've all been wondering what's been going on with the gharial and the suspect was that it's either a parasite, a disease, a virus.
In fact, wild speculation all over the world about what was going wrong with the gharial.
But this has really narrowed it down because, as Fritz and Brian just explained, the culprit has got to be some sort of a toxin.
The vets have discovered how the gharial died, but the presence of a toxin has opened up a new can of worms for Rom.
What is this toxin? Is it still lurking in the Chambal? How did it get there? The Chambal itself is one of India's healthiest waterways, but the river it flows into, just downstream of the sanctuary, is far from clean.
The Yamuna may be a sacred river, but after flowing through the industrial heartlands of Delhi and Agra, it's one of the most polluted in the world.
And Rom suspects this might be the source of the lethal toxin that has devastated the gharial.
We're walking along the banks of the Chambal.
Actually, it's the end of the Chambal, because in a few seconds we're going to be arriving at the confluence of the Yamuna River and the Chambal, and I think you'll be able to see for yourselves - we've got one of the dirtiest rivers in India just here meeting one of the cleanest rivers in India.
If you come over to the edge here and look down, you suddenly see what I was talking about.
The Yamuna River sweeps down from Delhi and Agra and meets the Chambal River here and from what I've been told, the coliforms, in other words the bacteria and nasty stuff that causes disease, has a count of about 14,000 here and the count for the Chambal River is 21.
So, my guess is if you took a sip of this water, you probably wouldn't last more than a few minutes, whereas everyone drinks the Chambal water.
If another piece in the puzzle of the gharial die-off is the food chain, in other words the fish that the gharial eat, the obvious answer is that polluted fish from the Yamuna are entering the Chambal and probably moving upstream.
A remarkable factor could be what the fisherman recently told us, that there were more than 40 different species of fish in the Yamuna previously, and now there's just one.
And that happens to be an exotic, the African tilapia.
So, something very seriously going wrong here, ecologically speaking.
The fact that that many species of fish have disappeared and are being replaced by one species, the only one that can stand this kind of toxicity and turbidity, in the mess that we call the Yamuna River.
As soon as the weather warmed up, there were no more gharial dying on the Chambal.
But there's no evidence that the toxin, whatever it is, has left the ecosystem and there's every good reason to believe that the die-off could happen again, when the cold weather returns.
There is a silver lining on this, however.
Never before has there been so much attention focused on the gharial and how to save it.
The government, the researchers, the people who have been working on gharial in the past, everyone is incredibly motivated.
And now permissions have been given, and everyone is on board to try to find the answers.
But until this toxin and its source can be identified and removed from the Chambal, the struggle to save the gharial in the wild must be fought elsewhere.
And Rom has just received a package from a colleague, which suggests that Katernia Ghat may be just the place.
Last year, our friend and fantastic naturalist photographer, Suresh Chaudhary, was up at Katernia Ghat, along with the wildlife warden, Ramesh Pandey, and they saw an incredible sight and filmed it.
LOW-PITCH SQUEAKING The lack of nesting sites at Katernia Ghat is so acute that when last year's 16 gharial nests hatched, 500 babies took their first steps on the same few yards of sand.
All on the very same island where Rom witnessed this year's laying.
We were up at Katernia Ghat just two months ago in April.
On that one little island, which had maybe 16 or 18 nests last year, there were at least 20, possibly 25 or more nests, on that one tiny island.
Can you imagine what we're gonna see? I mean, it's phenomenal.
It may appear from these scenes that the gharial species is in rude health.
But there are only so many nests here, because there is nowhere else suitable for them on the entire river.
Due to the tiny size of the sanctuary, only a handful of these babies, if any, have survived.
But it's a remarkable sight and the first time it's ever been filmed, and Rom wants to congratulate his Katernia Ghat colleague.
Hello.
Suresh? It is fantastic! I've never seen so many gharial, in one place, at one time, in my entire life.
I couldn't believe it! But there's a storm brewing at Katernia Ghat.
So what's happening to the nests? The news that Rom's just received is that the south-west monsoon has arrived at Katernia Ghat.
An annual onslaught of 80 per cent of India's rainfall, the monsoon arrives on the south coast in June and spreads north across the country with clockwork predictability.
But this year the rains have arrived two weeks early, and the river is in full spate, rising perilously close to the top of the gharial nesting island.
As Rom races up from Chennai, forest guard, Ramrup, is mounting a rescue mission to the island.
And it's a catastrophic scene.
More than half of the sandbank has been swept away, together with hundreds of eggs.
Desperate to save what they can, the forest guards slap the surface of the sand like gharial mothers listening for the calls of any babies that may have already hatched.
But there's no response.
With eggs washing away before their eyes, they have little choice.
They collect the handful of surviving nests for captive rearing, and as the island crumbles around their feet, they retreat to solid land.
Within hours the river, in full monsoon spate, has sealed the fate of the sanctuary's only gharial nesting site.
Meanwhile, Rom has arrived in Katernia Ghat.
I heard a little earlier, while I was down in the Croc Bank, that the river has risen much, much sooner than it usually does, and this has put the main nesting banks into jeopardy.
Rom doesn't realise quite how dramatic the change is.
My God, man! It's just amazing how different it is.
The pontoon bridge that was there in the summer, it's gone.
The sandbanks that we saw over there with the big gharial basking on 'em, totally gone.
The river's from one bank to the other now.
And what he's about to discover is that the gharials' nesting island and all their nests have been obliterated by the flood.
That chunk of blank water over there, that's where the nesting island was.
That's where all the gharial laid their eggs this year.
25 nests or more.
And it's gone.
I mean, it's completely gone.
Man! It's kind of like a ship going down with all hands lost.
There's not even a trace of it left.
The gharial just did what they always do, what they're programmed to do, and they've done it right for millions of years.
It's just that it's a very changed scene now.
You've got deforestation in the upper Himalayas and these rivers run much, much faster than they ever did.
In addition to that, we've got the spectre of global warming, which is messing up seasons and maybe this is a symptom of that.
We've got over a billion people on the sub-continent and they may not be physically entering the sanctuary, but the pressures from the outside, the pressures from upriver, are very visible and have created this disaster this year.
The disaster on the Girwa is yet another body-blow to the survival of the gharial in the wild.
The future of the Chambal population is hanging by a thread, and here in Katernia Ghat, the wild hatched contribution from a quarter of the world's gharial nests will be nil.
Once again this ups the ante for Rom's eggs at the Croc Bank, because these eggs, and the few rescued from the sandbank, now bear even more responsibility for the future of the species.
But a captive population means very little with no wild habitat, so before he returns to the Croc Bank, Rom's investigating where gharial might nest in the future.
This Right behind us, right here, is where the nesting island was and now all you see is water.
It just totally swept it away.
What we're gonna do now is try to check out this island because this is the closest possible nesting place for next year's gharial to nest.
Stepping off the boat, Rom wants to make sure any lurking wildlife knows he's coming.
I don't wanna get drafted I don't wanna go I don't want nobody to shoot me In the foxhole Foxhole.
What about bears? Do bears live in this? We're not exactly in the middle of gharial habitat here.
We're looking in fact at, what I would consider, good rhino and elephant habitat.
But the purpose of this somewhat ridiculous-looking exercise is to try to find an embankment, which might be suitable for next year's gharial nesting.
I was hoping that the land would start sloping upwards, but it doesn't seem to be.
It's very level and I am not a rhino.
Actually, we're going down again, that's not a very good sign.
Getting back down into mud.
It's kinda disappointing.
Umit doesn't really look great for the gharial, because I was hoping the island would slope up enough, so we'd be able to find an embankment.
Even if it wasn't sandy, we could at least do something with it.
Enough habitat manipulation, getting rid of some vegetation and piling up sand might create ideal gharial nesting habitat.
But you've got to start with something to begin with, something higher than the river level and here we are standing in almost knee-deep water.
Anyway, it was a try.
As Rom already knows in this tiny stretch of protected habitat, suitable sandbanks are few and far between.
Especially, when the monsoon floods are this ferocious.
More and more, we're kind of opening up to the idea that we're creating a fantastically disastrous climate change and it's already happening.
The gharial is so tied to what you could call the rhythms of the planet, that it is not going to be able to adjust.
They can't move away, they've got to nest traditionally where they've always nested, come hell or, in this case, high water.
Rom is realising that conservation in the future is going to have to be much more proactive.
Wouldn't it be great if we could just leave nature to itself and everything would be just fine? Unfortunately, it's not that way, and more and more, it looks like we have to make interventions.
We actually have to change habitat to make it more suitable for animals like the gharial.
It lost all its nesting habitat this year.
Now, we've got to make plans for next year.
And what ten years from now? I've been involved in gharial conservation since the beginning and I'm not gonna quit now.
It's my top priority.
Without the dedication of a handful of people like Rom, the gharial would have gone extinct long ago.
Faced with this year's disasters, the species' future is resting firmly on their shoulders.
Back in Chennai, Rom is about to find out if his Croc Bank eggs can bring any hope.
What happens with these eggs when they're ready to hatch, the erbaby starts moving around inside the egg, and .
.
can you hear that? It's just a very slight sound, but it's a little grunt coming from inside the egg.
The gharial actually communicates with its parents and tells the female when it's ready to emerge.
The whole clutch starts singing in a chorus.
This is when motherly love comes in and she digs him out.
In this case it's us, so we're the surrogate daddies here.
Let's see if this guy will hatch right in my hand.
Yeah, yeah, yeah, yeah.
He's coming, he's coming, he's coming, he's coming! In the wild the mother's digging would encourage them to break out of their shells.
But here in Rom's maternity ward, he's lending a helping hand.
Look at that! Look at that! Absolutely amazing.
Gharials have been hatching for millions and millions of years.
What I'm observing right now, is somethingit goes way back in time to the time of the dinosaurs and beyond.
(Yeah, yeah, yeah.
) 'Seeing this fills me with a sense of wonder, I can never shake.
' (Wow!) This little hatchling, can grow up to six metres, 20 feet long, but at this stage it's so vulnerable.
(Oi! And there he is, he's all the way out.
) This little newly hatched gharial doesn't know it, but he could just mean the future for the survival of the species.
It seems like we've perfected the art of breeding them in captivity beautifully, but what's gonna happen to them next? That is the problem.
Rom's 30-year struggle to save the gharial is reaching its end game.
Right now, it's time to decide whether there's still a place for this magnificent creature in our modern world.
The realisation that an animal as fantastic as the gharial could be on the verge of extinction, should make us feel really deeply ashamed of ourselves.
There's just so much more we can do, and we're not doing it.
Next week, Natural World reveals why the fate of Portugal's cork forests, one of the wildest places in Europe, may depend on bottles of wine.
HARMONICA PLAYS
It evolved before the dinosaurs and at the peak of its range, it thrived in rivers from Spain to Japan.
At 20 feet long and a tonne in weight, it is the ultimate fish-eating crocodile, and one of evolution's most successful species.
BABY GHARIALS SQUEAK The gharial's continued existence on the planet is owed in part to one man - Romulus Whitaker.
In the 1970s, Rom and his colleagues brought the gharial back from the very edge of extinction, and they have spent the past 30 years fighting to re-establish this crocodile and protect its ever-dwindling habitat.
They were making slow, but steady progress, until last winter, when a mysterious and unprecedented mass die-off brought this giant reptile to its knees.
Is Rom about to witness the first extinction of a crocodilian in human history? Or can he and his team save this mighty creature from this current crisis? This is the story of a crocodile which, after 150 million years of existence, has been reduced to less than 200 breeding animals.
HE PLAYS BLUES I can remember the time I saw my first live gharial.
The first time I ever picked one up.
I think my sense of amazement for this creature just hasn't changed, hasn't diminished a bit.
It is just a too much animal.
GHARIAL GROWLS As a child, Rom moved to India with his family.
In this wildlife wonderland, he developed a passion for all things reptilian.
Enthralled by snakes and captivated by crocodiles, he made them his life's work, and 60 years on, he is a living legend in the worlds of herpetology and conservation.
But the animal that has cast the greatest spell over him is India's iconic crocodile, the gharial.
Evolution has tuned this thing to be the most efficient fish catcher, the best river crocodile the universe has ever produced.
The gharial is perfectly adapted to its aquatic habitat.
Powered by its muscular tail, its webbed feet and natural goggles make it a swimming machine.
It's able to control its specific gravity by shifting its internal organs, rising and falling at will.
And its slender snout with razor-sharp teeth is the ultimate fish-catching tool.
But the gharial's extreme specialisations make it uniquely vulnerable.
The gharial is just so finely tuned, and so closely linked to its river habitat, that if anything goes wrong, the gharial would be like a fish out of water.
When Rom conducted India's first croc surveys in the 1970s, he found that there were less than ten adult males surviving in the wild.
With habitat conservation and a restocking programme, by 2006, total population numbers had increased to over 1,000.
But in December 2007, the recovering gharial were dealt a devastating blow.
OK, lots means how many gharial are dead? No, there's something very, very serious going on here.
I'll get up there as soon as I can.
This has gotta happen now, it's very, very urgent.
The Chambal River Sanctuary in northern India is home to nearly half of the world's population of wild gharial.
But as Rom had learnt, 10% of this vital population has died in sudden and mysterious circumstances.
I'm fearing the worst, because this is really a case of all your apples in one basket.
If something is wiping out the gharial and it's contagious, or it's something irreversible, then I don't know where it's gonna end.
And no sooner has Rom arrived than another dead gharial has washed up, bringing the death toll to 90.
It's a devastating scene.
But Rom's emotions must be put on hold, as Rom the scientist takes over.
This is basicallyan adult female.
In a way the most important segment or sector of the population is the females, who lay the eggs and populate the river, so We're gonna try to learn as much as we can from this loss.
News of the disaster has rippled across the world.
A major species is on the brink.
Emergency response teams have been dispatched to the Chambal, and Rom has joined a group of Indian and international vets.
They set to work with an impromptu autopsy on the banks of the river.
The colour of the flesh is normal and it's very fresh.
The autopsy is vital to discover what killed this gharial, and may provide clues as to what's causing the larger die-off.
This animal has literally just died.
I mean, we're talking about earlier this morning.
That means it's in a good state of preservation, you know? At this stage in the examination you don't try to interpret everything you see, you're just trying to make sure you don't miss anything in the picture, so then you can see if the pieces makes sense, so you make sure you describe each piece at this stage.
You don't find something and say, "This is a sign of that disease".
The vets address each of the organs in turn.
The lungs show no obvious signs of damage, but the team is particularly interested in the joints and kidneys, which show an unusual build-up of a powdery white substance.
The team have gathered as many clues as they can from this specimen.
I don't know what anyone else has learned about this, but I've learned a heck of a lot, because the previous animals looked at were all quite rotten already, and a lot of the organs had either dissolved, or were discoloured.
But I think the major thing that we're gonna learn out of this is what the veterinary doctors come up with.
This is really a grim scenario.
My colleagues and I have worked on rivers like the Chambal since the 70s and these are animals so close to our hearts.
I think we're trying to deal with the situation, the tragedy of it, probably the same way you deal with it on the front line when a war's going on.
It's that bad.
This is the time when all the birds go home.
As the team head home too, Rom is wondering whether there are any more clues as to the cause of the disaster elsewhere in the area surrounding the river.
Back in the 1970s, we did some of the first crocodile surveys and found that the Chambal, one of the wildest rivers left in India, still had some gharial, and sure enough it turned out to be ultimately the place where the release programme was started, and in 1979, the government formed the National Chambal Sanctuary to protect this fantastic river stretch of over 400 kilometres, and now it does have the largest population of gharial in the world.
It is not just conservation laws that have preserved the sanctity of this landscape.
These wild Chambal ravines used to be the hide-out of really famous bandits, dacoits called Makhan Singh .
.
and Man Singh and the famous bandit queen, Phoolan Devi.
Their days are over, but the place is still wild, it's still a dangerous place.
There are still some dangerous folks around.
But what it's done for the Chambal river is actually protected the place, because people just were scared to come here.
That's probably one reason why the gharial has survived here, and nowhere else.
Where bandits once prowled, it is now down to Rom and his colleagues to protect the gharial and its river.
And it seems the perils are now more complicated than population pressure alone.
The Chambal may feel like a pristine wilderness, but somewhere in the river lurks the menace that's decimating its most precious inhabitant.
The next morning finds the vets hard at work, carrying out another autopsy, this time on a baby gharial.
Working in their hotel bathroom, they are weighing up three possible causes of death - poisoning, parasites and infection.
But they need to compare their samples with those from a healthy living gharial.
So Rom and the team head back to the river.
Helping to co-ordinate the operation is one of India's leading environmentalists, Kartick Satyanarayan.
Take the entire kit, dog catcher, everything.
So that's the net they brought last night.
Yeah.
This is the one Dibulal got? Yeah, but we've got a back-up net here too, a huge one, which Basu got.
OK.
And we have a third net, which came from Agra.
I don't think we're taking any chances.
If we need something we'll call for you.
They do say that too many cooks spoil the soup.
In this case, everyone's essential.
An operation like this, if it's not well planned, obviously it's not gonna succeed, so it's worth all this banter and backing and forthing to make sure we've all got it straight.
Let's go.
I love it when someone just says the right word and everyone starts moving! Good.
Thanks, Kartick! Fantastic.
And we get in here.
OK.
Come on, let's go.
To catch at least one live healthy gharial is very important for the vet doctors because they need to check the blood, and you can't take blood out of a dead gharial, the blood congeals.
So we very much need a live gharial.
Although the Chambal River Sanctuary is 250 miles long, the affected gharial have all come from a 25-mile stretch.
It also appears that only a certain size class of animals is being affected.
Adding to the mystery is the fact that other river reptiles, like the mugger crocodile and soft-shell turtles, appear to be in robust health.
And birds that share the gharial's diet also seem to be unaffected.
We're looking at a fish-eating bird and they've got the same food chain as the gharial has, so if the gharial is being affected by something in the fish, in the food chain, why aren't the birds? But while Rom is busy mulling over the mystery, Kartick has got to work.
And in one of the many nets, he's landed the catch of the day and brought a smile to Rom's face.
Kartick! Oh, man, she's gorgeous.
Fantastic, man.
This is so good, man.
Oh, she's beautiful.
She's beautiful.
Absolutely.
GHARIAL GROWLS Mmmm! Yeah, I feel the way you do.
She's talking.
Don't worry, you won't be out for long.
So fortuitous because the doctors are arriving at the same time, so we've got all the experts and now we'll be able to get a blood sample.
This looks like a good place.
'I think that went incredibly well.
'First of all, the odds of us catching a live gharial 'within a few hours of trying, 'and we got it right within the size class 'of the animals which are dying in the Chambal, 'the foreign vets, they got samples of blood, 'cells from the liver, 'they got a bit of gastric content, in other words the stomach contents.
'There is a bit of pain when the needle goes into the skin, 'because it does have nerves, just like any of us getting an injection, 'but he didn't really struggle.
' The point is we're trying to find the source of this problem, and for one gharial to suffer for a few minutes a bit of pain, I think is really necessary at this point because we're trying to get to the bottom of the major die-off, which has never happened to any crocodilian that we know of.
Scientists and ecologists fear that we are on the brink of multiple extinctions, as ecosystems around the world collapse.
Could the mysterious die-off of gharial be a foreshadowing of some larger cataclysmic event? OK, this is a very sacred moment.
We've got to remember that gharial are able to turn around almost completely And as another of our most endangered animals is brought to the brink, is the world finally ready to sit up and take notice? Wow! Fantastic, eh? Fantastic.
Ah! While Rom is waiting for the vets to report their findings, he heads back south to Chennai and the Madras Crocodile Bank.
This is the centre he established in 1976 for the captive breeding of India's endangered crocodiles.
Over the years it has bred thousands of animals for release into the wild.
It's now an internationally renowned research centre and educational facility, and headquarters for Rom's conservation work.
Croc Bank is really the base of all our conservation operations on crocodilians in India.
Whatever we've learned about crocodilians, this is the repository.
This is where we start out on all our fieldwork, and this is where we end up when we come home.
Over three decades, Rom has built up the Croc Bank's gharial population.
It's an insurance policy against their decline in the wild.
The Chambal die-off has reduced wild breeding numbers to below 200.
Rom's efforts here are suddenly key to the survival of the species.
In the 1970s, the Croc Bank inherited its first four gharial.
There are now 13 adults and these are the two sexually mature males.
At the start of the annual breeding cycle, each attempts to assert its dominance over the other.
This is the height of the mating season, and we get to see some incredible stuff here in the gharial breeding pit.
This is the time of year when one adult male tries to outdo the other one and chase him out.
It can't get out of here, so sometimes massive fights ensue.
The males might work out their own pecking order, but it was up to Rom to perfect the art of breeding them.
Back in the 70s, we didn't really have a clue how to breed them in captivity.
They'd never bred in captivity before.
What was critical and pretty obvious, from the beginning, was that we had to have adult animals and it took 13 years before the gharial finally grew his ghara, on the tip of his snout, and we realised, OK, now it's the time.
The ghara, which gives the gharial its name, is a lump of cartilage which grows on the snout of mature males, and plays a key role in attracting a mate.
Their real method of attracting the females is doing something we call a buzz-snort.
It kind of goes like prr-rr-rrrp.
It sounds very impolite, but it seems to be very effective and it's created by the fact that the ghara of the male, sitting on top of its nostrils, sort of modifies the sound of its hissing into this very, very weird, but effective way of attracting females.
When they finally did start breeding, it was an amazing day for us.
The first clutch of eggs, I think it was just 12 eggs, and virtually every one of those eggs hatched, so we knew we were doing something right.
What Rom and his team achieved in the 1970s was vital for the future of the species.
It was extremely important for us to breed the gharial in captivity, at that stage.
It was down to 200 in the wild.
These things were really endangered so it was critical that we got them to breed in captivity.
Rom's captive-bred gharials have been released into the wild in two locations - on the Chambal, and at a sanctuary on the River Girwa called Katernia Ghat.
Rom needs to make sure that the Chambal's devastating die-off hasn't taken hold in this second sanctuary, so he's travelled to Katernia Ghat to see for himself.
For Rom, it's like coming home.
This is Katernia Ghat.
We've got 15-20 kilometres of pristine river.
We've got gharial, we've got mugger, bird-life I'd call it one of the best-kept secrets in India, really.
The Garden of Eden for one of my favourite animals, the gharial.
But all the other life here too.
It is totally amazing.
Rom's first task is to travel the length of the protected area and carry out a census, checking on the numbers and health of the Katernia Ghat's gharial.
'It's just incredible to think what's going on in the Chambal right now 'and gharial just dying like flies, 'but it's even more important that a place like Katernia Ghat 'is secure for gharial.
' In 2006 there were some 60 adult gharial living in the Katernia Ghat Sanctuary.
Rom's hoping that this population has at least remained stable.
That's a big gharial.
A preliminary tour has revealed about 30 gharial and thankfully these animals are all in good health.
I would say here is a secure population, and as a back-up to the Chambal population, it's now become more and more important to make sure that this stays intact.
But Katernia Ghat is minute, and Rom's "secure population" has little more than three miles of ideal habitat in which to live.
You have to look at it in a global perspective.
You've got probably 25% of the entire breeding population of gharial in the entire world right here, in a little chunk of habitat, with no protection below and no protection above, so it's very finite and it's very fragile.
And although these gharial are free from the mystery die-off, they are beset on all sides by other pressures that may prove to be just as deadly.
Even right in the sanctuary here there are several villages, people living here.
This is a very, very packed state, the state of Uttar Pradesh.
Population pressures are everywhere.
A major threat to the wildlife at Katernia Ghat is fishing.
Illegal in the sanctuary itself, it happens right up to its borders both up and downstream.
Subsistence fishermen and gharial have long competed for the same catch, but today's contract fishermen and monofilament nets give people an unfair advantage, and have an unfortunate side effect for the gharial.
Downstream outside of the sanctuary, fishing is a big thing, and you can see the prey base for gharial is perfect here, but the trouble is, if gharial start messing around in this, they get their teeth caught in it and they get twisted up, and they might even drown.
This is a big problem.
Luckily, they've sorted it out inside the sanctuary, but a gharial doesn't know where the sanctuary boundaries are, he comes downstream and gets caught, it's a very, very bad business for a gharial.
The threats to Katernia Ghat's gharial are obvious to Rom, but the cause of the die-off elsewhere remains a mystery.
Speculation about infectious disease and parasites is rife, but the vets are concentrating on poisoning through the food chain.
Another Indian animal that might hold a clue to the gharials' fate is the vulture.
It shares a diet with many of India's scavengers.
Where the rest of these scavengers go from strength to strength, vultures alone are circling towards extinction.
The reason why it's such a pleasure to see these vultures up here is because in the last ten years we've lost maybe even more than 90% of India's vultures, because of a specific drug called diclofenac.
It's a simple drug given by farmers to their cattle to reduce pain, but it's something that attacks the kidneys of the vulture, and they die very, very quickly.
Rom suspects something similar may be causing the mass gharial die-off, and that whatever is killing the gharial in the Chambal may also be specific to just that species.
But for the moment it seems that the gharial at Katernia Ghat are at least safe from the die-off.
And that evening, as Rom returns, the sanctuary is about to play host to a remarkable spectacle.
For over 150 million years, gharial have nested on riverbanks.
But now, in one of their last strongholds, they are reduced to nesting on just one sandbank.
And Rom may be about to witness one of the last times this ever happens.
It's It's getting close to sunset.
I'm kinda surprised, but it looks like one of the gharial is starting to climb the bank.
From here, anyway, it looks like she's full-bellied, full of egg.
She goes up in a jerky way, it's a very steep bank WHISPERS: It's a very steep bank.
I don't wanna disturb her! And they've got rather weak legs, strong for swimming, but weak for climbing up on land, so she sort of humps her way up the slope.
But there are other gharial interested in this particular sandbank.
Females that have already nested are watching proceedings as closely as Rom.
There's another one coming up, a larger one.
She looks slimmer.
Looks like she has already laid her eggs, and she's a little worried about that one digging up top.
This is her defensive mood.
It doesn't matter that it's another gharial, it's somebody digging.
I don't think she likes it.
There's a very good chance that one of them will scoop out the eggs of the previous nester.
There's definitely an urge to protect their own nest site.
As the camera struggles with the fading light, more gharial arrive.
The island is getting crowded, and dominant females begin to compete for the prime sites at the top of the sandbank.
Both of the big females are knocking their beaks together.
They're trying to sort out who's boss here.
This is really I've never seen this before, but it's obvious that the females are defending their nest site, even from other females, so there is some sort of pecking order, some hierarchy going on.
And this is a tiny sandbank so it really is just not enough space for all these animals, which is one obvious reason why this is happening.
But the gharial aren't just competing with each other for the prime nesting sites, they also need to see off the threat of a mugger crocodile, who is equally interested in the high sandbank.
The dominant females are distracted, leaving an opportunity at the other end of the island.
The smaller one is now on top.
She's starting to scrape sand with her legs.
I can actually see, even without the binocs, sand flying through the air.
The gharial uses its powerful rear legs and webbed feet to excavate a nest pit as deep as its legs are long.
Yeah, she's starting to dig down inside.
Now you start seeing different colour sand coming out.
It was dry sand at first.
That dark stuff is the damp sand from inside so she's making her hole now.
In a scene that has never before been documented, the island has become a busy maternity ward, as more gharial arrive and stake their claim to a precious patch of sand.
They too begin their timeless nesting ritual, a process that will last well into the night.
It's getting very dark.
I can just barely see what's going on.
There's definitely a couple of them laying though.
Good luck to them.
Each gharial will lay up to 50 eggs, which will incubate for 70 to 80 days and hatch just before the onset of the monsoon.
Next morning, and the nesting frenzy is over, leaving the island covered with the scars of last night's laying activity.
Amazed by the overcrowding on the tiny sandbank, Rom and forest guard Ramrup head over to count the freshly dug nests.
Using a wire rod to gently probe the sand, they find six freshly laid nests, bringing the total on this island to a very crowded 24.
It's totally amazing, and we're probably looking at maybe even a quarter of the entire nesting effort of all of the world's wild gharial on this little tiny spit of land that's like, what, about 40 metres long, 20 metres wide.
It's a tiny place, totally vulnerable to the monsoon floods, but the vast majority of the gharial in the Girwa are laying their eggs right here, and we've noticed that some nests, I mean, some of the nesters, have dug out other nests and there are a couple of eggs lying around, so this is very limited, and it's very worrisome too, because what'll happen when another monsoon comes? Look at this steep embankment on this side.
Come over and check this out.
Another steep embankment on this side.
It's so obvious the gharial prefer this.
They want to climb up on to something high.
That really makes sense in every sense of the word, because this river does rise very fast, and if it rose unseasonably early, all the eggs would be submerged and drown.
Rom hopes his worst fears won't be realised, because this small island seems to be the only nesting place for gharial in the entire sanctuary.
It's a precarious scenario for an already endangered species.
Just a few miles downstream is a potent vision of why, today, there are so few gharial nesting sites.
Where for millions of years they happily excavated their sandy nests, India is now extracting building sand on an epic scale.
Sand mining.
Sand mining in river beds.
I mean, we've got to have sand.
India is growing.
Growing, growing, growing.
Building more houses.
Construction.
Everything.
But mining it from a riverbed is no good.
It's no good for the hydrology and it's certainly no good for gharial.
Gharial lose their basking spots, they lose their nesting spots.
Same for turtles.
It's just bad all round.
Although this riverbed looks like a desert, it wasn't long ago that this was prime gharial habitat.
Every river bed in India is getting drier and drier every year and this isn't natural.
We're just taking the water for irrigation, we're damming it, we're barraging it, we're canalling it.
We're doing everything to get water to other places for agriculture.
Needed stuff, but needed - sure - it's got to be done sensibly, too.
We've got to remember, we're looking after gharial too, OK? Back at the Croc Bank, the most successful enclosure emulates the steep sandbanks at Katernia Ghat.
And while Rom has been away, his prize female Roxanne has laid her annual clutch of eggs.
This is the spot, right, where they marked it? Although this sandbank may be perfect for Roxanne to nest, conditions here in India's deep south are too hot for successful incubation.
So the eggs need to be excavated to ensure that they will hatch.
The reason why he's got a stick in his hand is because they are defensive with their nests.
Nothing like a saltwater crocodile or a mugger, but Nonetheless, they do have sharp teeth, and they really don't like the idea of you stealing their eggs.
It's not just Roxanne who's upset by Rom's nest raiding.
The dominant male, too, is taking an unhealthy interest in proceedings He's a big guy and a little scarier than the females, so we just have to be a little careful here! Because you know, when you get concentrated on your work, you just forget that there's some toothy little creature behind you.
It's very important to mark the orientation of each egg, because if you turn the egg over, you can actually kill the embryo.
In the present context of the gharial being critically endangered and the die-off that's happening in the Chambal, captive breeding programmes like this become more and more important.
And it's really critical that we have this repository of captive animals, you know, as a safety measure.
We're hoping like hell that the gharial doesn't go extinct in the wild, but nonetheless, this the back-up, this is the insurance policy.
46, 47and one last one.
That's the largest clutch size we've ever had at Madras Crocodile Bank for the gharial.
That's amazing.
48 eggs.
Thanks, Roxanne! OK, let's get the eggs up, we're gonna incubate them.
Basically, what we have to do here is candle the eggs because that determines whether the eggs are fertile or not and Nikhil is an expert at this, but to be able to do it, we have to switch the lights off.
OK, let's see what we've got.
This moving dark horizontal line shows that the egg is viable.
The black spot at the top of the egg is called banding and grows as the embryo continues to develop.
So, the embryo always attaches itself to the top.
Most of the time.
We're calling that a fertile one, right? We always used to say, "Treat the eggs like nitroglycerine.
" Easy, easy, don't roll them! Don't let them explode.
Oh, that's nice.
With his precious clutch safely under wraps, Rom has returned to the Chambal, site of the winter die-off, to follow up on the mystery.
With the arrival of warmer weather, the gharial deaths appear to have stopped, and through study of their autopsy samples, the vets may have reached a breakthrough.
They have discovered that the white powder observed on the gharials' organs is crystallised uric acid.
Uric acid is not very soluble, and at a certain level it reaches saturation.
When it reaches saturation, it crystallises out.
OK.
The amount of uric acid in the blood is controlled by the kidneys, and when levels are this high, it points to kidney failures.
Kidneys are an essential organ in gharial, just like they are in any animal.
When uric acid builds up in the joints it causes gout, a debilitating condition, that in a reptile can be deadly.
An animal with this kind of thing cannot move its limbs anymore.
So they come along, go up to the sandbank too fast, and very often they cannot even control their swimming, because they need their hands and feet for balancing.
Wow.
That makes it even sadder in a way, doesn't it? It does, yes, yes.
Very sad.
Filmed during the die-off, these images show the death throes of a gharial crippled by agonising gout.
The winter's record low temperatures on the Chambal, may also have played a part in this disaster.
The solubility of uric acid varies by temperature, so the cold temperature certainly could play a role into the manifestation of disease in this instance.
Death is unavoidable.
The vets believe that the die-off was caused by gout, brought on by a combination of cold weather and kidney failure, and that the kidney failure itself was caused by poisoning.
It must be a toxin.
It must be something toxic in the water or in the fish or something that they're eating.
They've got a toxin in them somehow.
It seems that Rom's vulture hunch was right, and that the Chambal gharial have been poisoned.
We've all been wondering what's been going on with the gharial and the suspect was that it's either a parasite, a disease, a virus.
In fact, wild speculation all over the world about what was going wrong with the gharial.
But this has really narrowed it down because, as Fritz and Brian just explained, the culprit has got to be some sort of a toxin.
The vets have discovered how the gharial died, but the presence of a toxin has opened up a new can of worms for Rom.
What is this toxin? Is it still lurking in the Chambal? How did it get there? The Chambal itself is one of India's healthiest waterways, but the river it flows into, just downstream of the sanctuary, is far from clean.
The Yamuna may be a sacred river, but after flowing through the industrial heartlands of Delhi and Agra, it's one of the most polluted in the world.
And Rom suspects this might be the source of the lethal toxin that has devastated the gharial.
We're walking along the banks of the Chambal.
Actually, it's the end of the Chambal, because in a few seconds we're going to be arriving at the confluence of the Yamuna River and the Chambal, and I think you'll be able to see for yourselves - we've got one of the dirtiest rivers in India just here meeting one of the cleanest rivers in India.
If you come over to the edge here and look down, you suddenly see what I was talking about.
The Yamuna River sweeps down from Delhi and Agra and meets the Chambal River here and from what I've been told, the coliforms, in other words the bacteria and nasty stuff that causes disease, has a count of about 14,000 here and the count for the Chambal River is 21.
So, my guess is if you took a sip of this water, you probably wouldn't last more than a few minutes, whereas everyone drinks the Chambal water.
If another piece in the puzzle of the gharial die-off is the food chain, in other words the fish that the gharial eat, the obvious answer is that polluted fish from the Yamuna are entering the Chambal and probably moving upstream.
A remarkable factor could be what the fisherman recently told us, that there were more than 40 different species of fish in the Yamuna previously, and now there's just one.
And that happens to be an exotic, the African tilapia.
So, something very seriously going wrong here, ecologically speaking.
The fact that that many species of fish have disappeared and are being replaced by one species, the only one that can stand this kind of toxicity and turbidity, in the mess that we call the Yamuna River.
As soon as the weather warmed up, there were no more gharial dying on the Chambal.
But there's no evidence that the toxin, whatever it is, has left the ecosystem and there's every good reason to believe that the die-off could happen again, when the cold weather returns.
There is a silver lining on this, however.
Never before has there been so much attention focused on the gharial and how to save it.
The government, the researchers, the people who have been working on gharial in the past, everyone is incredibly motivated.
And now permissions have been given, and everyone is on board to try to find the answers.
But until this toxin and its source can be identified and removed from the Chambal, the struggle to save the gharial in the wild must be fought elsewhere.
And Rom has just received a package from a colleague, which suggests that Katernia Ghat may be just the place.
Last year, our friend and fantastic naturalist photographer, Suresh Chaudhary, was up at Katernia Ghat, along with the wildlife warden, Ramesh Pandey, and they saw an incredible sight and filmed it.
LOW-PITCH SQUEAKING The lack of nesting sites at Katernia Ghat is so acute that when last year's 16 gharial nests hatched, 500 babies took their first steps on the same few yards of sand.
All on the very same island where Rom witnessed this year's laying.
We were up at Katernia Ghat just two months ago in April.
On that one little island, which had maybe 16 or 18 nests last year, there were at least 20, possibly 25 or more nests, on that one tiny island.
Can you imagine what we're gonna see? I mean, it's phenomenal.
It may appear from these scenes that the gharial species is in rude health.
But there are only so many nests here, because there is nowhere else suitable for them on the entire river.
Due to the tiny size of the sanctuary, only a handful of these babies, if any, have survived.
But it's a remarkable sight and the first time it's ever been filmed, and Rom wants to congratulate his Katernia Ghat colleague.
Hello.
Suresh? It is fantastic! I've never seen so many gharial, in one place, at one time, in my entire life.
I couldn't believe it! But there's a storm brewing at Katernia Ghat.
So what's happening to the nests? The news that Rom's just received is that the south-west monsoon has arrived at Katernia Ghat.
An annual onslaught of 80 per cent of India's rainfall, the monsoon arrives on the south coast in June and spreads north across the country with clockwork predictability.
But this year the rains have arrived two weeks early, and the river is in full spate, rising perilously close to the top of the gharial nesting island.
As Rom races up from Chennai, forest guard, Ramrup, is mounting a rescue mission to the island.
And it's a catastrophic scene.
More than half of the sandbank has been swept away, together with hundreds of eggs.
Desperate to save what they can, the forest guards slap the surface of the sand like gharial mothers listening for the calls of any babies that may have already hatched.
But there's no response.
With eggs washing away before their eyes, they have little choice.
They collect the handful of surviving nests for captive rearing, and as the island crumbles around their feet, they retreat to solid land.
Within hours the river, in full monsoon spate, has sealed the fate of the sanctuary's only gharial nesting site.
Meanwhile, Rom has arrived in Katernia Ghat.
I heard a little earlier, while I was down in the Croc Bank, that the river has risen much, much sooner than it usually does, and this has put the main nesting banks into jeopardy.
Rom doesn't realise quite how dramatic the change is.
My God, man! It's just amazing how different it is.
The pontoon bridge that was there in the summer, it's gone.
The sandbanks that we saw over there with the big gharial basking on 'em, totally gone.
The river's from one bank to the other now.
And what he's about to discover is that the gharials' nesting island and all their nests have been obliterated by the flood.
That chunk of blank water over there, that's where the nesting island was.
That's where all the gharial laid their eggs this year.
25 nests or more.
And it's gone.
I mean, it's completely gone.
Man! It's kind of like a ship going down with all hands lost.
There's not even a trace of it left.
The gharial just did what they always do, what they're programmed to do, and they've done it right for millions of years.
It's just that it's a very changed scene now.
You've got deforestation in the upper Himalayas and these rivers run much, much faster than they ever did.
In addition to that, we've got the spectre of global warming, which is messing up seasons and maybe this is a symptom of that.
We've got over a billion people on the sub-continent and they may not be physically entering the sanctuary, but the pressures from the outside, the pressures from upriver, are very visible and have created this disaster this year.
The disaster on the Girwa is yet another body-blow to the survival of the gharial in the wild.
The future of the Chambal population is hanging by a thread, and here in Katernia Ghat, the wild hatched contribution from a quarter of the world's gharial nests will be nil.
Once again this ups the ante for Rom's eggs at the Croc Bank, because these eggs, and the few rescued from the sandbank, now bear even more responsibility for the future of the species.
But a captive population means very little with no wild habitat, so before he returns to the Croc Bank, Rom's investigating where gharial might nest in the future.
This Right behind us, right here, is where the nesting island was and now all you see is water.
It just totally swept it away.
What we're gonna do now is try to check out this island because this is the closest possible nesting place for next year's gharial to nest.
Stepping off the boat, Rom wants to make sure any lurking wildlife knows he's coming.
I don't wanna get drafted I don't wanna go I don't want nobody to shoot me In the foxhole Foxhole.
What about bears? Do bears live in this? We're not exactly in the middle of gharial habitat here.
We're looking in fact at, what I would consider, good rhino and elephant habitat.
But the purpose of this somewhat ridiculous-looking exercise is to try to find an embankment, which might be suitable for next year's gharial nesting.
I was hoping that the land would start sloping upwards, but it doesn't seem to be.
It's very level and I am not a rhino.
Actually, we're going down again, that's not a very good sign.
Getting back down into mud.
It's kinda disappointing.
Umit doesn't really look great for the gharial, because I was hoping the island would slope up enough, so we'd be able to find an embankment.
Even if it wasn't sandy, we could at least do something with it.
Enough habitat manipulation, getting rid of some vegetation and piling up sand might create ideal gharial nesting habitat.
But you've got to start with something to begin with, something higher than the river level and here we are standing in almost knee-deep water.
Anyway, it was a try.
As Rom already knows in this tiny stretch of protected habitat, suitable sandbanks are few and far between.
Especially, when the monsoon floods are this ferocious.
More and more, we're kind of opening up to the idea that we're creating a fantastically disastrous climate change and it's already happening.
The gharial is so tied to what you could call the rhythms of the planet, that it is not going to be able to adjust.
They can't move away, they've got to nest traditionally where they've always nested, come hell or, in this case, high water.
Rom is realising that conservation in the future is going to have to be much more proactive.
Wouldn't it be great if we could just leave nature to itself and everything would be just fine? Unfortunately, it's not that way, and more and more, it looks like we have to make interventions.
We actually have to change habitat to make it more suitable for animals like the gharial.
It lost all its nesting habitat this year.
Now, we've got to make plans for next year.
And what ten years from now? I've been involved in gharial conservation since the beginning and I'm not gonna quit now.
It's my top priority.
Without the dedication of a handful of people like Rom, the gharial would have gone extinct long ago.
Faced with this year's disasters, the species' future is resting firmly on their shoulders.
Back in Chennai, Rom is about to find out if his Croc Bank eggs can bring any hope.
What happens with these eggs when they're ready to hatch, the erbaby starts moving around inside the egg, and .
.
can you hear that? It's just a very slight sound, but it's a little grunt coming from inside the egg.
The gharial actually communicates with its parents and tells the female when it's ready to emerge.
The whole clutch starts singing in a chorus.
This is when motherly love comes in and she digs him out.
In this case it's us, so we're the surrogate daddies here.
Let's see if this guy will hatch right in my hand.
Yeah, yeah, yeah, yeah.
He's coming, he's coming, he's coming, he's coming! In the wild the mother's digging would encourage them to break out of their shells.
But here in Rom's maternity ward, he's lending a helping hand.
Look at that! Look at that! Absolutely amazing.
Gharials have been hatching for millions and millions of years.
What I'm observing right now, is somethingit goes way back in time to the time of the dinosaurs and beyond.
(Yeah, yeah, yeah.
) 'Seeing this fills me with a sense of wonder, I can never shake.
' (Wow!) This little hatchling, can grow up to six metres, 20 feet long, but at this stage it's so vulnerable.
(Oi! And there he is, he's all the way out.
) This little newly hatched gharial doesn't know it, but he could just mean the future for the survival of the species.
It seems like we've perfected the art of breeding them in captivity beautifully, but what's gonna happen to them next? That is the problem.
Rom's 30-year struggle to save the gharial is reaching its end game.
Right now, it's time to decide whether there's still a place for this magnificent creature in our modern world.
The realisation that an animal as fantastic as the gharial could be on the verge of extinction, should make us feel really deeply ashamed of ourselves.
There's just so much more we can do, and we're not doing it.
Next week, Natural World reveals why the fate of Portugal's cork forests, one of the wildest places in Europe, may depend on bottles of wine.
HARMONICA PLAYS