BBC Life (2009) s01e02 Episode Script
Reptiles and Amphibians
ATTENBOROUGH: The island of Komodo in Indonesia, remote and barren.
Few people live here.
It's ruled by a giant reptile.
It looks like a survivor from the age of the dinosaurs.
The Komodo dragon.
Nine feet long.
A top predator.
Only one thing can challenge a dragon's dominance.
Another dragon.
In the breeding season, males are drawn into savage conflict.
Huge claws and 60 serrated teeth can inflict terrible damage.
The Komodo dragon is the only reptile that still rules the land as dinosaurs once did.
It can dominate here because it has no competition.
But for the rest of the world's reptiles and amphibians, survival is a much tougher struggle.
Like the dragon, reptiles and amphibians seem primitive, better suited to an earlier age.
Yet they have a surprising repertoire of extraordinary strategies.
And they still thrive in many parts of the planet.
This is the story of how they do so.
South America, the remote jungle where Brazil and Venezuela meet.
Sheer-sided mountains rise up from the jungle.
Few places on earth are wetter.
It's the home of some ancient and very peculiar amphibians.
The waterfall toad is just an inch long, the size of a postage stamp.
Its special gripping hands enable it to clamber safely, high in the treetops.
But it's not alone up here.
Most frogs and toads avoid predators by hopping out of danger.
But this toad never evolved the ability to hop for more than an inch, and that's nowhere near enough.
One way it gets eaten, the other way is thin air.
Not much of a choice.
But this isn't suicide.
It's a deliberate strategy, and one that depends on the size and strength of those extraordinary hands.
Free-falling like this is a very effective way of escaping.
However, another toad on this same mountain has elaborated this strategy.
It lives a mile above the forest on this plateau, cut off from the world below.
This is a pebble toad.
It too is only an inch long.
These rocks may seem a paradise for a toad.
It's even wetter than the forest below and there are no snakes.
But there is a hunter here.
A toad-eating tarantula.
It ambushes its prey.
Like the waterfall toad, the pebble toad can't hop, but it has a different defence.
It tenses its muscles, becomes rigid and turns itself into a rubber ball.
It's so tiny and weighs so little that bouncing doesn't hurt it at all.
Bizarre innovations like these are one of the reasons why amphibians and reptiles are still so successful.
Some of them, however, have hardly changed for tens of millions of years.
(TOADS CROAKING) Brazil's Pantanal.
Over 50,000 square miles of swamp.
In the dry season, the water is reduced to isolated pools.
And then, they contain the greatest concentration of crocodiles on earth.
(SNARLING) These caiman crocodiles are trapped and fast running out of food.
It will be a long time before the rains return and the rivers rise, bringing with them the caiman's prey, fish.
Being cold-blooded, they can go without food for months and stay inactive, except when they squabble.
(SNORTING) (HISSING) At last, the rains return and rivers swell.
All reptiles are experts at saving energy.
The caimans simply line up and wait for the fish to come to them.
Reptiles and amphibians must warm their bodies before they can become active and until then, they are slow-moving and vulnerable.
The quickest way to gain heat is to bask in the sun, as this basilisk lizard from Central America is doing.
The trouble is that exposing yourself inevitably makes you easily seen.
But a conspicuous perch over a river like this seems to be making yourself unnecessarily prominent.
This basilisk's greatest threat comes from the sky.
Dark shapes overhead make it nervous.
A hunting bird might expect it to flee to the trees.
In fact, it does the opposite.
(SPLASHING) This skitter across the surface of the water earns it precious seconds, and the nickname Jesus Christ lizard.
It drives its feet down so hard and so fast that it never sinks deeper than a few inches.
A human would need to run at 65 miles an hour to do this.
Reptiles are certainly expert at avoiding trouble, but they're also very good at finding a way to live in places that don't seem to suit them at all.
They once included the largest animals that have ever walked the earth, the dinosaurs.
And some living ones are a million times smaller than T.
rex, smaller indeed than some insects.
The Brazilian pygmy gecko could sit comfortably on a fingertip.
It's so exceptionally small that no other reptiles compete with it.
But it's so nimble it can escape from the hunting monsters of the undergrowth.
It is so small that it has special problems with, for example, rain.
It could drown in a drop.
But its skin is hydrophobic.
Rain cannot wet it.
A tumble into a puddle, you might think, would risk death by drowning.
But the gecko is unsinkable.
It's so light and its skin so water-repellent that it can literally stand on water.
Such miniaturisation is certainly very impressive, but the reptile body can be transformed even more dramatically.
One of the most bizarre of all reptiles hunts insects here in Madagascar.
The praying mantis has 360-degree vision.
But it hasn't seen the danger that is now approaching.
A panther chameleon.
Every part of its body has become specialised for a life of stealth among the branches.
Its toes have become grasping pincers.
Its eyes rotate so it can look in all directions.
Its skin can change colour for camouflage or to signal emotions.
The chameleon body is concealed from both predator and prey so it can launch a surprise attack.
The tongue is like a missile aimed at its prey's head to neutralise its defences.
Chameleons, in short, are so perfectly adapted to a life spent hunting in trees that it is hard to imagine how they could live anywhere else.
The Namib Desert.
There are no trees for hundreds of miles.
Yet these are undoubtedly chameleon footprints.
This female Namaqua chameleon is searching for a mate.
No part of her body seems suited to such an environment.
Her feet, that could give her such a good grip on twigs, should surely be useless on soft sand.
But she's able to spread them like snowshoes.
She needs to get warm and active while the desert is still cool, so she exploits the chameleon's versatile skin.
The side facing the sun goes dark to absorb the sun's heat, while the other remains light and minimises the heat escaping from her body.
She's hungry and food is scarce.
But she's still not quick enough to grab these desert beetles.
Her solution is simple.
She finds at last a little vegetation and waits for a shade-seeking beetle to come to her.
On she goes in her search for a mate.
At last, a wandering male.
But he may not treat her as she might wish.
The courtship of most chameleons is gentle.
But in this desert, a male meets a female so rarely he can't risk being rejected.
She marches on, now carrying a new generation.
A six-month freeze, when temperatures may drop to minus 40 degrees centigrade, should surely make things impossible for a reptile.
But here in Canada, beneath the thawing snow, something stirs.
A male red-sided garter snake.
He survived the winter by hibernating underground, where the temperature never dropped below zero.
The weak sun persuades more males to emerge.
They are cold and can't move fast, yet they are in an urgent race.
The first males to warm up will have a head start when the first females appear.
Melt water provides the first drink they've had for six months.
At last, a female has emerged.
The warmest males will inevitably be the first to react to her smell.
She will only mate once, so competition between them is intense.
This male has overslept.
He will need hours to warm up.
At the moment, he stands no chance of mating.
Most of the other males are ready to chase females but curiously, some leave the race and go to join the cold male.
They slide their warm bodies over him just as they would if they were courting a female.
More and more males crowd round him.
Why? Their relative temperatures show what's going on.
His cool body, showing as blue, is quickly warming as it absorbs heat from the other males.
He's a trickster.
He's fooled the others by giving off a scent just like a female's and they are trying to mate with him.
He only needs a few minutes of this to steal enough heat from his rivals to catch up and join the chase.
Every spring, tens of thousands of garter snakes fight it out in this mating frenzy.
It is, in numbers, the greatest gathering of reptiles in the world.
Getting a mate is just the first challenge a reptile faces when it's ready to breed.
This collared iguana in Madagascar will only lay one batch of eggs this year, so she needs somewhere safe to hide them.
Her eggs are much sought after by predators.
They are excellent pre-packaged meals.
She appears to have the answer.
She covers all traces of where she buried them.
It's a good strategy.
But not good enough.
Hognose snakes have learned to keep watch on iguana nesting sites and to note the precise place where the eggs lie buried.
She has been completely outwitted.
She can only stand by and watch as her precious eggs are eaten.
Next year, she will have to find a nesting site without a hognose snake.
On the other side of the world, in the Sonoran Desert of Arizona, a similar drama has a very different outcome.
A female horned lizard guards her buried eggs and is keeping a lookout for anything that might interfere with them.
A western patchnose snake.
It is an egg-eater.
And she won't stand for it.
The patchnose is no match for this kind of aggression.
Her eggs are safe, for now.
Another predator, a coachwhip snake, and this species is a lizard-eater.
And she can tell the difference.
The snake is too fast for her to outrun it, so she makes herself look larger and taller.
The snake is wary of swallowing anything that looks as big and as spiky as this.
And now the lizard plays her trump card.
The snake isn't accustomed to prey that does this.
One very confused snake.
Now she can return to guard duty.
And several months later, she is rewarded with her first baby.
Looking after your eggs is an even greater challenge for reptiles that have left land to live in the sea.
The Pacific island of Niue is home to the world's entire population of one particular type of sea krait.
This snake is superbly adapted to life underwater, except when it's time to breed.
After a few minutes in a mating coil, the female is fertilised.
But now she has a problem.
Reptile eggs can't survive underwater.
The developing young would drown.
They have to be able to breathe air.
She and her eggs are both vulnerable to predators if they return to land.
But she has an extraordinary solution.
She dives beneath the island to find the entrance to a long underwater tunnel.
At the far end is a cave with an air pocket.
This is the dry land her eggs need.
There are no predators here.
The cavern is sealed by a roof above and the water below.
She searches for a crevice where she can deposit her eggs.
The eggs will be completely safe here and she can return to the open sea.
Six months later, a baby snake takes its first breath.
Somehow, the young snakes must find their own way to water.
Then, down the tunnel and out to sea.
(THUNDER CRACKING) A male giant bullfrog.
Reptiles and amphibians rarely care for their young after they hatch but this South African bruiser is an exception.
(CROAKING) The males sort out their dominance through combat.
The strongest will mate with the most females.
You might not expect such an aggressive male to be a caring father.
Yet one male stays behind to watch over not just his own, but everyone else's offspring.
The females laid their eggs in the shallows around the margins of the pool.
But the sun is intense and the shallows have shrunk to a single pool.
There is a real danger that the tadpoles will be stranded.
The guardian male recognises the problem.
They will be dead within an hour unless he can do something to help.
There is only one thing he can do to save them, dig a channel to the main pool.
They are safe.
Remarkable innovations have made amphibians and reptiles a modern success story.
What is more, among their ranks is one reptile that is still an undisputed top land predator.
The Komodo dragon.
They mostly hunt deer, which they ambush and easily overpower.
But in hard times, the dragons risk hunting something much bigger water buffalo, an animal ten times their size.
Until now, a dragon hunt has never been filmed.
It's the dry season.
A buffalo sleeps through the heat of the day in one of the last waterholes.
Dragons lurk around the margins.
The buffalo seems to view them as just an irritation, not a danger.
A serious mistake.
(GRUNTING) The dragon is wary.
A jab or a kick could injure it fatally.
The bites are just flesh wounds, but other dragons are alert now.
Like sharks, they are excited by blood.
The buffalo leaves with just a limp.
The dragons appear to have failed.
Yet they show a peculiar interest in the buffalo and follow it wherever it goes.
As the days pass, the buffalo's wounds don't heal.
It starts to weaken.
The dragons' hunting method begins to come clear.
A brand-new discovery reveals that the dragon has venom, like a snake.
The bite will eventually prove fatal, but it's going to take several weeks.
The dragons, however, can afford to wait for a meal of this size.
They simply stick close to their victim and conserve their energy.
Thousands of years ago, dwarf elephants lived here.
The dragons probably hunted them in exactly the same way.
But the process is a long, drawn-out one.
Three weeks later and the buffalo is very weak.
The dragons sense that the end is near.
They must remain wary.
The buffalo could still lash out.
Gradually, they close in to try and finish it off.
The dragons' strategy is certainly merciless.
But it is the only way that they can get a meal like this and in hard times, they need it if they are to survive.
The buffalo died in the night.
Ten big dragons have gathered to feed.
They strip the buffalo to the bone in just four hours.
This is the biggest venomous animal on the planet.
We don't need tales of Jurassic Park and Velociraptors to see a reptile-dominated world.
It's all here.
No one has ever before followed the whole process of a Komodo dragon hunting a buffalo.
So cameraman Kevin Flay and researcher Matt Swarbrick didn't know what to expect.
They thought it would be a physical challenge but they hadn't bargained for emotional turmoil as well.
They've reached Komodo after a four-day journey.
Kevin, an expert at filming reptiles, knows they're in dragon territory.
SWARBRICK: Look how wide that is.
- Look at that.
- Yeah.
Their only protection is these rangers, armed with sticks.
These big ones look really scary, actually.
And not until they come really in close and when they're by the camera, then you tend to question your faith in our friends with the sticks.
We got any guys with sticks? But this dragon isn't a big one.
At five foot, this dragon is just over half grown.
The really big ones live inland, which is exactly where Kevin and Matt must go to find a place where dragons and buffalo might meet.
FLAY: We could spend five weeks walking around all over the island just trying to find dragons randomly coming across buffalos.
But fortunately for us, it is the dry season and there's only one decent waterhole left on the island.
And both the dragons and the buffalo require water, obviously, which brings them together.
ATTENBOROUGH: Kevin decides to wait here, but after a few days with no sign of dragons, it looks like the wrong decision.
Oh, here comes a buffalo.
You know, this is about as exciting as the day gets.
Look.
See that? Hello, mate.
ATTENBOROUGH: After almost a week, something changes and a couple of dragons appear.
- Have we got a ranger here? - Guys, can we have a ranger? (WHISPERING) Always know how dangerous a situation is.
But it does seem a bit concerning that one of our rangers is sat up in a tree.
ATTENBOROUGH: But the dragons show no interest in the buffalo or the crew, and the frustration continues.
Yet their task seems so simple.
SWARBRICK: So, what we need is for him to film him attacking him.
But it looks like he is about to attack him.
Just cut myself.
That's not good in dragon country.
(CHUCKLES) I'd better be careful.
We've got to start now.
We've got to start our walk home.
It takes just over an hour but the thing is, if stuff's happened and you've managed to film good stuff, then it's really easy.
You just trot on home and find some dinner and find out what the rats have done to your room.
But it's still really hot at this time of day and so if you've not filmed a lot and you've just sat here all day long, then it's a hell of a long walk home.
ATTENBOROUGH: They have a lot of long walks home.
But finally, a new dragon appears.
Something about its attitude seems different.
Maybe we could be on to something.
But I've now lost the other dragon, which makes me a bit nervous.
ATTENBOROUGH: At first it's wary, unwilling to get too close to the buffalo.
(WHISPERING) Big dragons involved here.
Somewhere.
That came from absolutely nowhere.
That guy has got some real attitude.
ATTENBOROUGH: That first bite and the smell of blood set off a chain reaction.
All the dragons seem to come to life.
The peaceful watering hole is now a dangerous place to be.
I've definitely got two heads at the moment.
One as a cameramen saying, "Yes, brilliant!" And the other one is thinking, "That poor animal.
" You know, that's not nice.
That's really not nice.
- RANGER 1: Careful.
- Here it comes, here it comes.
- RANGER 2: Camera, camera.
- Got it.
SWARBRICK: Nice.
Quickly, quickly, quickly.
My heart's pumping a bit.
(CHUCKLES) At least my heart still works.
Good lord, that was a bit hairy.
ATTENBOROUGH: Now the crew must follow the buffalo every day to finish their filming job.
This begins to take a toll on their emotions.
He knows he's injured, he can't walk properly, and you've got these predators just gathering around him, waiting for the opportunity.
It's gruesome.
ATTENBOROUGH: Shadowing the buffalo means staying close to the dragons, too.
This is mad.
We've just followed the buffalo and I think six dragons? I've lost track now, I think it's six dragons, down into the riverbed.
And, you know, they're stalking it.
We're all a bit nervous.
It's actually quite frightening, I have to say.
SWARBRICK: They're so capable and so unafraid of us and they would have no problems at all causing us major, major damage.
At the moment, I feel about 5 to 10% confident that I'm safe here.
But the truth is we just don't know.
ATTENBOROUGH: As the days pass, Kevin and Matt can't help but feel more deeply involved.
And I'm sure they're starting to think of us as death, you know, this camera team, because although we're not influencing it in any way, really, we're always there when the dragons are there and, you know, she's sick, so we're following her.
And you see her looking back at you and I'm sure I feel like, you know, Death and his scythe coming in to kill.
I'm not really that sure how cut out I am for this.
If the game is spending all your time watching an animal die, I don't know about that.
ATTENBOROUGH: The dragons seem brutal, yet this is the only way they can get large prey.
For the team, the event has become personal.
SWARBRICK: I think as we've got to know him, and, you know, we see him every morning, we see him every evening, you know, you build up a relationship with him.
And today I think he kind of gave up.
ATTENBOROUGH: The next day, it is all over.
FLAY: Now it's over, you sit back and reflect, you sort of feel, "That was just astonishing.
" And it feels so primeval.
It feels you're watching something from a different era.
And they really are the most fantastic things to be with.
Scary, awesome, you know, to look at, you just feel that you are looking at something from Jurassic Park.
Few people live here.
It's ruled by a giant reptile.
It looks like a survivor from the age of the dinosaurs.
The Komodo dragon.
Nine feet long.
A top predator.
Only one thing can challenge a dragon's dominance.
Another dragon.
In the breeding season, males are drawn into savage conflict.
Huge claws and 60 serrated teeth can inflict terrible damage.
The Komodo dragon is the only reptile that still rules the land as dinosaurs once did.
It can dominate here because it has no competition.
But for the rest of the world's reptiles and amphibians, survival is a much tougher struggle.
Like the dragon, reptiles and amphibians seem primitive, better suited to an earlier age.
Yet they have a surprising repertoire of extraordinary strategies.
And they still thrive in many parts of the planet.
This is the story of how they do so.
South America, the remote jungle where Brazil and Venezuela meet.
Sheer-sided mountains rise up from the jungle.
Few places on earth are wetter.
It's the home of some ancient and very peculiar amphibians.
The waterfall toad is just an inch long, the size of a postage stamp.
Its special gripping hands enable it to clamber safely, high in the treetops.
But it's not alone up here.
Most frogs and toads avoid predators by hopping out of danger.
But this toad never evolved the ability to hop for more than an inch, and that's nowhere near enough.
One way it gets eaten, the other way is thin air.
Not much of a choice.
But this isn't suicide.
It's a deliberate strategy, and one that depends on the size and strength of those extraordinary hands.
Free-falling like this is a very effective way of escaping.
However, another toad on this same mountain has elaborated this strategy.
It lives a mile above the forest on this plateau, cut off from the world below.
This is a pebble toad.
It too is only an inch long.
These rocks may seem a paradise for a toad.
It's even wetter than the forest below and there are no snakes.
But there is a hunter here.
A toad-eating tarantula.
It ambushes its prey.
Like the waterfall toad, the pebble toad can't hop, but it has a different defence.
It tenses its muscles, becomes rigid and turns itself into a rubber ball.
It's so tiny and weighs so little that bouncing doesn't hurt it at all.
Bizarre innovations like these are one of the reasons why amphibians and reptiles are still so successful.
Some of them, however, have hardly changed for tens of millions of years.
(TOADS CROAKING) Brazil's Pantanal.
Over 50,000 square miles of swamp.
In the dry season, the water is reduced to isolated pools.
And then, they contain the greatest concentration of crocodiles on earth.
(SNARLING) These caiman crocodiles are trapped and fast running out of food.
It will be a long time before the rains return and the rivers rise, bringing with them the caiman's prey, fish.
Being cold-blooded, they can go without food for months and stay inactive, except when they squabble.
(SNORTING) (HISSING) At last, the rains return and rivers swell.
All reptiles are experts at saving energy.
The caimans simply line up and wait for the fish to come to them.
Reptiles and amphibians must warm their bodies before they can become active and until then, they are slow-moving and vulnerable.
The quickest way to gain heat is to bask in the sun, as this basilisk lizard from Central America is doing.
The trouble is that exposing yourself inevitably makes you easily seen.
But a conspicuous perch over a river like this seems to be making yourself unnecessarily prominent.
This basilisk's greatest threat comes from the sky.
Dark shapes overhead make it nervous.
A hunting bird might expect it to flee to the trees.
In fact, it does the opposite.
(SPLASHING) This skitter across the surface of the water earns it precious seconds, and the nickname Jesus Christ lizard.
It drives its feet down so hard and so fast that it never sinks deeper than a few inches.
A human would need to run at 65 miles an hour to do this.
Reptiles are certainly expert at avoiding trouble, but they're also very good at finding a way to live in places that don't seem to suit them at all.
They once included the largest animals that have ever walked the earth, the dinosaurs.
And some living ones are a million times smaller than T.
rex, smaller indeed than some insects.
The Brazilian pygmy gecko could sit comfortably on a fingertip.
It's so exceptionally small that no other reptiles compete with it.
But it's so nimble it can escape from the hunting monsters of the undergrowth.
It is so small that it has special problems with, for example, rain.
It could drown in a drop.
But its skin is hydrophobic.
Rain cannot wet it.
A tumble into a puddle, you might think, would risk death by drowning.
But the gecko is unsinkable.
It's so light and its skin so water-repellent that it can literally stand on water.
Such miniaturisation is certainly very impressive, but the reptile body can be transformed even more dramatically.
One of the most bizarre of all reptiles hunts insects here in Madagascar.
The praying mantis has 360-degree vision.
But it hasn't seen the danger that is now approaching.
A panther chameleon.
Every part of its body has become specialised for a life of stealth among the branches.
Its toes have become grasping pincers.
Its eyes rotate so it can look in all directions.
Its skin can change colour for camouflage or to signal emotions.
The chameleon body is concealed from both predator and prey so it can launch a surprise attack.
The tongue is like a missile aimed at its prey's head to neutralise its defences.
Chameleons, in short, are so perfectly adapted to a life spent hunting in trees that it is hard to imagine how they could live anywhere else.
The Namib Desert.
There are no trees for hundreds of miles.
Yet these are undoubtedly chameleon footprints.
This female Namaqua chameleon is searching for a mate.
No part of her body seems suited to such an environment.
Her feet, that could give her such a good grip on twigs, should surely be useless on soft sand.
But she's able to spread them like snowshoes.
She needs to get warm and active while the desert is still cool, so she exploits the chameleon's versatile skin.
The side facing the sun goes dark to absorb the sun's heat, while the other remains light and minimises the heat escaping from her body.
She's hungry and food is scarce.
But she's still not quick enough to grab these desert beetles.
Her solution is simple.
She finds at last a little vegetation and waits for a shade-seeking beetle to come to her.
On she goes in her search for a mate.
At last, a wandering male.
But he may not treat her as she might wish.
The courtship of most chameleons is gentle.
But in this desert, a male meets a female so rarely he can't risk being rejected.
She marches on, now carrying a new generation.
A six-month freeze, when temperatures may drop to minus 40 degrees centigrade, should surely make things impossible for a reptile.
But here in Canada, beneath the thawing snow, something stirs.
A male red-sided garter snake.
He survived the winter by hibernating underground, where the temperature never dropped below zero.
The weak sun persuades more males to emerge.
They are cold and can't move fast, yet they are in an urgent race.
The first males to warm up will have a head start when the first females appear.
Melt water provides the first drink they've had for six months.
At last, a female has emerged.
The warmest males will inevitably be the first to react to her smell.
She will only mate once, so competition between them is intense.
This male has overslept.
He will need hours to warm up.
At the moment, he stands no chance of mating.
Most of the other males are ready to chase females but curiously, some leave the race and go to join the cold male.
They slide their warm bodies over him just as they would if they were courting a female.
More and more males crowd round him.
Why? Their relative temperatures show what's going on.
His cool body, showing as blue, is quickly warming as it absorbs heat from the other males.
He's a trickster.
He's fooled the others by giving off a scent just like a female's and they are trying to mate with him.
He only needs a few minutes of this to steal enough heat from his rivals to catch up and join the chase.
Every spring, tens of thousands of garter snakes fight it out in this mating frenzy.
It is, in numbers, the greatest gathering of reptiles in the world.
Getting a mate is just the first challenge a reptile faces when it's ready to breed.
This collared iguana in Madagascar will only lay one batch of eggs this year, so she needs somewhere safe to hide them.
Her eggs are much sought after by predators.
They are excellent pre-packaged meals.
She appears to have the answer.
She covers all traces of where she buried them.
It's a good strategy.
But not good enough.
Hognose snakes have learned to keep watch on iguana nesting sites and to note the precise place where the eggs lie buried.
She has been completely outwitted.
She can only stand by and watch as her precious eggs are eaten.
Next year, she will have to find a nesting site without a hognose snake.
On the other side of the world, in the Sonoran Desert of Arizona, a similar drama has a very different outcome.
A female horned lizard guards her buried eggs and is keeping a lookout for anything that might interfere with them.
A western patchnose snake.
It is an egg-eater.
And she won't stand for it.
The patchnose is no match for this kind of aggression.
Her eggs are safe, for now.
Another predator, a coachwhip snake, and this species is a lizard-eater.
And she can tell the difference.
The snake is too fast for her to outrun it, so she makes herself look larger and taller.
The snake is wary of swallowing anything that looks as big and as spiky as this.
And now the lizard plays her trump card.
The snake isn't accustomed to prey that does this.
One very confused snake.
Now she can return to guard duty.
And several months later, she is rewarded with her first baby.
Looking after your eggs is an even greater challenge for reptiles that have left land to live in the sea.
The Pacific island of Niue is home to the world's entire population of one particular type of sea krait.
This snake is superbly adapted to life underwater, except when it's time to breed.
After a few minutes in a mating coil, the female is fertilised.
But now she has a problem.
Reptile eggs can't survive underwater.
The developing young would drown.
They have to be able to breathe air.
She and her eggs are both vulnerable to predators if they return to land.
But she has an extraordinary solution.
She dives beneath the island to find the entrance to a long underwater tunnel.
At the far end is a cave with an air pocket.
This is the dry land her eggs need.
There are no predators here.
The cavern is sealed by a roof above and the water below.
She searches for a crevice where she can deposit her eggs.
The eggs will be completely safe here and she can return to the open sea.
Six months later, a baby snake takes its first breath.
Somehow, the young snakes must find their own way to water.
Then, down the tunnel and out to sea.
(THUNDER CRACKING) A male giant bullfrog.
Reptiles and amphibians rarely care for their young after they hatch but this South African bruiser is an exception.
(CROAKING) The males sort out their dominance through combat.
The strongest will mate with the most females.
You might not expect such an aggressive male to be a caring father.
Yet one male stays behind to watch over not just his own, but everyone else's offspring.
The females laid their eggs in the shallows around the margins of the pool.
But the sun is intense and the shallows have shrunk to a single pool.
There is a real danger that the tadpoles will be stranded.
The guardian male recognises the problem.
They will be dead within an hour unless he can do something to help.
There is only one thing he can do to save them, dig a channel to the main pool.
They are safe.
Remarkable innovations have made amphibians and reptiles a modern success story.
What is more, among their ranks is one reptile that is still an undisputed top land predator.
The Komodo dragon.
They mostly hunt deer, which they ambush and easily overpower.
But in hard times, the dragons risk hunting something much bigger water buffalo, an animal ten times their size.
Until now, a dragon hunt has never been filmed.
It's the dry season.
A buffalo sleeps through the heat of the day in one of the last waterholes.
Dragons lurk around the margins.
The buffalo seems to view them as just an irritation, not a danger.
A serious mistake.
(GRUNTING) The dragon is wary.
A jab or a kick could injure it fatally.
The bites are just flesh wounds, but other dragons are alert now.
Like sharks, they are excited by blood.
The buffalo leaves with just a limp.
The dragons appear to have failed.
Yet they show a peculiar interest in the buffalo and follow it wherever it goes.
As the days pass, the buffalo's wounds don't heal.
It starts to weaken.
The dragons' hunting method begins to come clear.
A brand-new discovery reveals that the dragon has venom, like a snake.
The bite will eventually prove fatal, but it's going to take several weeks.
The dragons, however, can afford to wait for a meal of this size.
They simply stick close to their victim and conserve their energy.
Thousands of years ago, dwarf elephants lived here.
The dragons probably hunted them in exactly the same way.
But the process is a long, drawn-out one.
Three weeks later and the buffalo is very weak.
The dragons sense that the end is near.
They must remain wary.
The buffalo could still lash out.
Gradually, they close in to try and finish it off.
The dragons' strategy is certainly merciless.
But it is the only way that they can get a meal like this and in hard times, they need it if they are to survive.
The buffalo died in the night.
Ten big dragons have gathered to feed.
They strip the buffalo to the bone in just four hours.
This is the biggest venomous animal on the planet.
We don't need tales of Jurassic Park and Velociraptors to see a reptile-dominated world.
It's all here.
No one has ever before followed the whole process of a Komodo dragon hunting a buffalo.
So cameraman Kevin Flay and researcher Matt Swarbrick didn't know what to expect.
They thought it would be a physical challenge but they hadn't bargained for emotional turmoil as well.
They've reached Komodo after a four-day journey.
Kevin, an expert at filming reptiles, knows they're in dragon territory.
SWARBRICK: Look how wide that is.
- Look at that.
- Yeah.
Their only protection is these rangers, armed with sticks.
These big ones look really scary, actually.
And not until they come really in close and when they're by the camera, then you tend to question your faith in our friends with the sticks.
We got any guys with sticks? But this dragon isn't a big one.
At five foot, this dragon is just over half grown.
The really big ones live inland, which is exactly where Kevin and Matt must go to find a place where dragons and buffalo might meet.
FLAY: We could spend five weeks walking around all over the island just trying to find dragons randomly coming across buffalos.
But fortunately for us, it is the dry season and there's only one decent waterhole left on the island.
And both the dragons and the buffalo require water, obviously, which brings them together.
ATTENBOROUGH: Kevin decides to wait here, but after a few days with no sign of dragons, it looks like the wrong decision.
Oh, here comes a buffalo.
You know, this is about as exciting as the day gets.
Look.
See that? Hello, mate.
ATTENBOROUGH: After almost a week, something changes and a couple of dragons appear.
- Have we got a ranger here? - Guys, can we have a ranger? (WHISPERING) Always know how dangerous a situation is.
But it does seem a bit concerning that one of our rangers is sat up in a tree.
ATTENBOROUGH: But the dragons show no interest in the buffalo or the crew, and the frustration continues.
Yet their task seems so simple.
SWARBRICK: So, what we need is for him to film him attacking him.
But it looks like he is about to attack him.
Just cut myself.
That's not good in dragon country.
(CHUCKLES) I'd better be careful.
We've got to start now.
We've got to start our walk home.
It takes just over an hour but the thing is, if stuff's happened and you've managed to film good stuff, then it's really easy.
You just trot on home and find some dinner and find out what the rats have done to your room.
But it's still really hot at this time of day and so if you've not filmed a lot and you've just sat here all day long, then it's a hell of a long walk home.
ATTENBOROUGH: They have a lot of long walks home.
But finally, a new dragon appears.
Something about its attitude seems different.
Maybe we could be on to something.
But I've now lost the other dragon, which makes me a bit nervous.
ATTENBOROUGH: At first it's wary, unwilling to get too close to the buffalo.
(WHISPERING) Big dragons involved here.
Somewhere.
That came from absolutely nowhere.
That guy has got some real attitude.
ATTENBOROUGH: That first bite and the smell of blood set off a chain reaction.
All the dragons seem to come to life.
The peaceful watering hole is now a dangerous place to be.
I've definitely got two heads at the moment.
One as a cameramen saying, "Yes, brilliant!" And the other one is thinking, "That poor animal.
" You know, that's not nice.
That's really not nice.
- RANGER 1: Careful.
- Here it comes, here it comes.
- RANGER 2: Camera, camera.
- Got it.
SWARBRICK: Nice.
Quickly, quickly, quickly.
My heart's pumping a bit.
(CHUCKLES) At least my heart still works.
Good lord, that was a bit hairy.
ATTENBOROUGH: Now the crew must follow the buffalo every day to finish their filming job.
This begins to take a toll on their emotions.
He knows he's injured, he can't walk properly, and you've got these predators just gathering around him, waiting for the opportunity.
It's gruesome.
ATTENBOROUGH: Shadowing the buffalo means staying close to the dragons, too.
This is mad.
We've just followed the buffalo and I think six dragons? I've lost track now, I think it's six dragons, down into the riverbed.
And, you know, they're stalking it.
We're all a bit nervous.
It's actually quite frightening, I have to say.
SWARBRICK: They're so capable and so unafraid of us and they would have no problems at all causing us major, major damage.
At the moment, I feel about 5 to 10% confident that I'm safe here.
But the truth is we just don't know.
ATTENBOROUGH: As the days pass, Kevin and Matt can't help but feel more deeply involved.
And I'm sure they're starting to think of us as death, you know, this camera team, because although we're not influencing it in any way, really, we're always there when the dragons are there and, you know, she's sick, so we're following her.
And you see her looking back at you and I'm sure I feel like, you know, Death and his scythe coming in to kill.
I'm not really that sure how cut out I am for this.
If the game is spending all your time watching an animal die, I don't know about that.
ATTENBOROUGH: The dragons seem brutal, yet this is the only way they can get large prey.
For the team, the event has become personal.
SWARBRICK: I think as we've got to know him, and, you know, we see him every morning, we see him every evening, you know, you build up a relationship with him.
And today I think he kind of gave up.
ATTENBOROUGH: The next day, it is all over.
FLAY: Now it's over, you sit back and reflect, you sort of feel, "That was just astonishing.
" And it feels so primeval.
It feels you're watching something from a different era.
And they really are the most fantastic things to be with.
Scary, awesome, you know, to look at, you just feel that you are looking at something from Jurassic Park.