0:00:06 > 0:00:12A monsoon storm on the coast of an island in the Indian Ocean.
0:00:17 > 0:00:22But this is not a normal tropical island.
0:00:22 > 0:00:24This is Madagascar.
0:00:28 > 0:00:34Once joined to Africa, Madagascar has been isolated for millions of years,
0:00:34 > 0:00:38and it has evolved a set of wildlife all its own.
0:00:38 > 0:00:42More than 80% of it is found nowhere else on earth.
0:00:44 > 0:00:50This strange island is split in two by a line of mountains running its length.
0:00:50 > 0:00:54The eastern slopes are drenched with rain and cloaked in jungle.
0:00:54 > 0:01:01But cross these mountains into the western side, and you are in another world.
0:01:03 > 0:01:10To live here, you need to cope with a landscape that is bone dry for most of the year.
0:01:10 > 0:01:14A land where rain is fleeting and quite unpredictable.
0:01:17 > 0:01:22And yet Madagascar's arid lands are full of life.
0:01:26 > 0:01:34Everything that lives here has its own fight for survival and resources as the seasons swing by.
0:01:34 > 0:01:40In this eccentric land, some of the strategies wildlife has developed are quite extraordinary.
0:02:06 > 0:02:11Madagascar is a vast island.
0:02:11 > 0:02:17A thousand miles from north to south, it is so big it has the variations in climate of a continent.
0:02:21 > 0:02:26The mountainous spine down its length is a barrier to rain.
0:02:26 > 0:02:31The land to the west is in a rain shadow.
0:02:31 > 0:02:35And the further south you go, the drier it gets.
0:02:41 > 0:02:45This is a journey through Madagascar's most challenging season,
0:02:45 > 0:02:52the great drought that grips the south and west of the island for more than nine months of every year.
0:02:55 > 0:03:00To survive these months, you need to be tough and ingenious.
0:03:01 > 0:03:04And Madagascar's wildlife is certainly both.
0:03:08 > 0:03:13Rising up from the southern flatlands is a strange, Grand Canyon-like landscape...
0:03:13 > 0:03:19a great plateau of sandstone beaten down by millions of years of erosion.
0:03:19 > 0:03:25It's August. Deep inland, far from the sea, it's searingly hot.
0:03:25 > 0:03:27And it hasn't rained for months.
0:03:29 > 0:03:31But it's not entirely dry here.
0:03:31 > 0:03:35In deep, dark canyons there are slashes of green.
0:03:38 > 0:03:44These lush forests are leafy all year, thanks to a constant source of water.
0:03:52 > 0:03:59The very depth of the canyon shades it from the sun and keeps it permanently moist.
0:04:00 > 0:04:08It's a rare oasis in an otherwise parched land, and it's a great attraction for wildlife.
0:04:11 > 0:04:15A dragonfly patrols a patch of stream.
0:04:15 > 0:04:18He's jealously guarding his precious territory,
0:04:18 > 0:04:22pushing out male rivals while he waits for the females to visit.
0:04:33 > 0:04:40And in this fortunate place lives a small family of lemurs Verreaux's sifakas.
0:04:40 > 0:04:46They spent the chilly night in high rocky caverns, safe from predators.
0:04:46 > 0:04:52At dawn, they move down into the canyon, stopping to warm up in the first rays of the sun.
0:04:53 > 0:04:56And there's another member of the family.
0:04:56 > 0:05:00A daughter, just a couple of weeks old.
0:05:02 > 0:05:09She has been able to grip her mother's fur unaided since she was born, and just as well...
0:05:11 > 0:05:17..because her mother crosses the canyon with vast leaps, as much as nine metres in a single bound.
0:05:27 > 0:05:32There is no shortage of food here for these vegetarian lemurs.
0:05:32 > 0:05:35But for now, the baby is totally reliant on milk.
0:05:35 > 0:05:39It will be another six months before she's completely independent.
0:05:56 > 0:06:03Like all lemurs, sifakas are primates, and their social bonds are strong.
0:06:08 > 0:06:12She will stay with her family in this vast canyon for the rest of her life.
0:06:21 > 0:06:26These lush canyons are a rare leafy oasis.
0:06:26 > 0:06:31The further south you go, the drier it gets.
0:06:31 > 0:06:36There are rivers here in the deep south, but they are highly seasonal.
0:06:36 > 0:06:40As the dry season takes hold, they run flat and broad...
0:06:40 > 0:06:43ankle-deep streams on a bed of sand.
0:06:45 > 0:06:52But the rivers carry just enough water and nutrients for ribbons of forest to grow.
0:07:10 > 0:07:14And the masters of these river forests are these.
0:07:14 > 0:07:17Ringtailed lemurs.
0:07:17 > 0:07:21In gangs of 15 strong, they have the run of the place.
0:07:32 > 0:07:35And it's the females who are in charge.
0:07:35 > 0:07:40With the burden of raising young, they must have access to the best food.
0:07:45 > 0:07:48These lemurs are protective of their patch.
0:07:48 > 0:07:52Scent marking makes it clear to other gangs where the border lies.
0:07:52 > 0:07:57As a group, they need to keep hold of their home territory.
0:07:59 > 0:08:01LEMURS WAIL AND SCREECH
0:08:01 > 0:08:04Intruders are seen off promptly.
0:08:08 > 0:08:13Green as this river forest looks, at this time of year there is only
0:08:13 > 0:08:17just enough food to go round, and these females all have babies to feed.
0:08:19 > 0:08:24They all gave birth at around the same time.
0:08:24 > 0:08:28By the time the rains return, the forest will be full of fruit,
0:08:28 > 0:08:33and that is just when the babies will be old enough to feed for themselves.
0:08:33 > 0:08:38It's a crucial adaptation to suit a place so driven by seasonal change.
0:08:46 > 0:08:49Motherhood is taking its toll...
0:08:49 > 0:08:52they are thin, and their fur is less than sleek.
0:08:54 > 0:08:56But the dry season will eventually pass
0:08:56 > 0:08:59and at least their forest is green all year.
0:09:03 > 0:09:09Further to the west is a swathe of forest that is much more demanding.
0:09:09 > 0:09:14It swings dramatically between wetness and desiccation.
0:09:20 > 0:09:24For most of the year, it is cracklingly dry.
0:09:28 > 0:09:33The most distinctive trees of these western dry forests are the Baobabs.
0:09:33 > 0:09:38Their trunks are huge and bulbous, the better to store water.
0:09:39 > 0:09:41They live for hundreds of years.
0:09:41 > 0:09:45A tree like this will have seen many dry seasons pass.
0:09:51 > 0:09:59It's now October, the height of the dry season, and it will be months before any significant rain falls.
0:10:00 > 0:10:04For everything that lives here, it's a test of endurance.
0:10:06 > 0:10:08Water is in short supply,
0:10:08 > 0:10:13just a few little temporary pools dotted between the trees.
0:10:38 > 0:10:42Everything must come here to drink.
0:10:42 > 0:10:47And that's risky. Their predators will know where they are.
0:10:50 > 0:10:54Brown lemurs creep timidly around the waterhole.
0:10:54 > 0:11:02With very little fresh greenery to eat, they must drink every day or risk death from dehydration.
0:11:02 > 0:11:08But every step on the carpet of dry leaves could reveal their presence.
0:11:15 > 0:11:18At this time of year, they have babies too.
0:11:18 > 0:11:20They're an easy target.
0:12:05 > 0:12:08But this hawk is only after water,
0:12:08 > 0:12:11a drink and a bathe.
0:12:26 > 0:12:32In such tough times, there are battles for territory in the most unexpected places.
0:12:36 > 0:12:42As night falls in the Baobab forest, an extraordinary crowd emerges.
0:12:49 > 0:12:52They are baby flatid bugs.
0:12:52 > 0:12:58By day they are barely visible, but at night they swarm over the trees and start to feed.
0:13:01 > 0:13:06They drink sap, and each settles itself into a spot on the branch.
0:13:12 > 0:13:16But even at this miniature level, there's a battle for resources,
0:13:16 > 0:13:20and here and there fist-fights break out.
0:13:20 > 0:13:24This curious spat has never been observed before.
0:13:28 > 0:13:31For the most part, however, they feed quietly.
0:13:31 > 0:13:36And as they feed, they excrete unwanted liquid, called honeydew.
0:13:36 > 0:13:39It coats the branches and remaining leaves.
0:13:41 > 0:13:46And this is very attractive to other insects that are out and about at night.
0:13:53 > 0:13:58And that, in turn, provides a feast for mouse lemurs.
0:13:59 > 0:14:05At around 60 grams, mouse lemurs are the world's smallest primates.
0:14:17 > 0:14:20These are all males.
0:14:20 > 0:14:23The females are fast asleep in tree holes, and have been for months.
0:14:23 > 0:14:28They can sleep right through the dry season, and they'll only emerge when the rains come.
0:14:28 > 0:14:31It's a way of saving energy.
0:14:35 > 0:14:37So for now, the males are on their own,
0:14:37 > 0:14:42feeding on anything that will take them through the lean times,
0:14:42 > 0:14:45and waiting for the day that the females awake.
0:14:49 > 0:14:57But of all Madagascar's southern habitats, none seems more challenging than this.
0:14:57 > 0:15:02This is the far south of the island, where there is little standing water.
0:15:02 > 0:15:06Rain is rare, and some years doesn't fall at all.
0:15:06 > 0:15:10The sandy, porous rock drains quickly.
0:15:10 > 0:15:15The forest that grows here is one of the strangest on earth.
0:15:15 > 0:15:19It's called the spiny forest, for good reason.
0:15:19 > 0:15:23There is nothing like it anywhere else in the world.
0:15:42 > 0:15:44The plants are viciously spiny...
0:15:44 > 0:15:52the spines collecting what little water there is in the air, and draining it back to the tree itself.
0:16:02 > 0:16:05These plants are seriously odd...
0:16:05 > 0:16:10with twisted, sprawling branches, these are octopus trees.
0:16:15 > 0:16:20And euphorbias, looking like strings of sausages.
0:16:20 > 0:16:22They barely even bother with leaves...
0:16:22 > 0:16:26they photosynthesise through the green of their stems.
0:16:26 > 0:16:30These are among the world's toughest plants.
0:16:30 > 0:16:34It would seem there is nothing edible here...
0:16:34 > 0:16:37what leaves there are are small, the better to avoid water loss,
0:16:37 > 0:16:40and tucked down among the spines.
0:16:40 > 0:16:43This place looks totally hostile.
0:16:59 > 0:17:04But here too live ghostly little lemurs.
0:17:13 > 0:17:17Verreaux's sifakas are among the hardiest of all the lemurs.
0:17:17 > 0:17:20And they are quite at home here too.
0:17:25 > 0:17:32They are perfectly adapted to this desiccated place, because they can go without drinking at all.
0:17:32 > 0:17:36They get all the moisture they need from these unappetising looking leaves,
0:17:36 > 0:17:39which they pick from between the spines.
0:17:45 > 0:17:52They even relish the euphorbia fruit, apparently not bothered by the fact that these trees are dripping with
0:17:52 > 0:17:55chemicals so strong they'd burn your skin.
0:18:06 > 0:18:08And they too have babies,
0:18:08 > 0:18:12born at what looks like the very worst time of the year.
0:18:22 > 0:18:24Life here seems generally much more challenging.
0:18:24 > 0:18:28Not only is there little to eat, these sifakas have to cope with
0:18:28 > 0:18:33jumping between thorns that would go through your fingers.
0:18:42 > 0:18:49It's hardly surprising that only half of sifaka babies make it to adulthood.
0:19:11 > 0:19:15Within just a few months, these babies will have to
0:19:15 > 0:19:19take the plunge and learn how to jump all by themselves.
0:19:19 > 0:19:22For now, they cling to their mother and discover what's edible.
0:19:47 > 0:19:55Back in the central canyon lands, the weeks pass. It's November, and there is still no rain.
0:19:55 > 0:19:57There hasn't been for eight months.
0:20:00 > 0:20:06The grassy plains are dry, but inside the canyon, thanks to the constantly flowing spring,
0:20:06 > 0:20:10it is still almost ludicrously luxuriant and full of life.
0:20:20 > 0:20:23Ringtails, the most adaptable of all lemurs,
0:20:23 > 0:20:26have found a home here too.
0:20:27 > 0:20:32They are the most widespread of lemurs, and they live all over the south of the island.
0:20:32 > 0:20:35And here they seem to have found a life of ease.
0:20:44 > 0:20:49They are able to take advantage of a range of food as it becomes available.
0:20:49 > 0:20:52They'll eat leaves, flowers and even insects.
0:20:52 > 0:20:58In an unpredictable place like Madagascar, that has helped them to thrive.
0:21:04 > 0:21:06The babies are growing up.
0:21:06 > 0:21:13Born at roughly the same time, every ringtail baby in the south is now about two months old.
0:21:13 > 0:21:18And this young male is starting to find his way around this bountiful place.
0:21:39 > 0:21:43But it will be a while before he's totally competent as a climber.
0:21:52 > 0:21:57He won't even be fully weaned for another three months.
0:22:04 > 0:22:10Although there is moisture in the leaves they eat, the ringtails can't go more than a day without drinking.
0:22:10 > 0:22:14But finding water is not difficult here.
0:22:14 > 0:22:16The stream never runs dry.
0:22:32 > 0:22:38Outside the canyon, however, the grass is tinder dry.
0:22:47 > 0:22:51Fire has been a factor here for millions of years.
0:22:59 > 0:23:03The grass burns rapidly, and the fire spreads quickly.
0:23:03 > 0:23:08These spots of flame and smoke flush insects from the grass,
0:23:08 > 0:23:13so they are a huge attraction for kites and kestrels.
0:24:39 > 0:24:45Back in the Baobab forest in the far west, it seems as parched as ever.
0:24:45 > 0:24:51But now, in late November, there are signs that things are about to change.
0:24:51 > 0:24:57The Baobabs' scrappy branches suddenly begin to put out a first flush of green leaves.
0:24:57 > 0:25:01They are drawing on the precious water they've stored in their fat trunks.
0:25:01 > 0:25:06There will soon be rain here, and the Baobabs sense that it's coming.
0:25:09 > 0:25:11There is a scent of rain in the air.
0:25:12 > 0:25:15Other life is beginning to stir.
0:25:19 > 0:25:21This little chameleon has not long hatched
0:25:21 > 0:25:23but already it's in a race.
0:25:23 > 0:25:29And it has one of the strangest strategies of all for dealing with the extreme dryness.
0:25:31 > 0:25:37They are Labord's chameleons, and they only live in this part of the island.
0:25:40 > 0:25:46This little male already has a voracious appetite...
0:25:46 > 0:25:49although this spider may be beyond him.
0:26:08 > 0:26:16These strange little chameleons have the shortest lifecycle of any land vertebrate in the world.
0:26:16 > 0:26:20They spent the last nine months underground, inside an egg,
0:26:20 > 0:26:24and now they have just eight weeks to grow to adult size.
0:26:39 > 0:26:43They will have to grow more than a centimetre a week.
0:26:48 > 0:26:50There is no time to waste.
0:26:50 > 0:26:55Conditions are so tough that living fast is the best strategy.
0:26:55 > 0:27:00By the time the rains begin, his life will be almost over.
0:27:10 > 0:27:13In fact the rains have already started...
0:27:13 > 0:27:16only a splash, but a sign of a deluge to come.
0:27:21 > 0:27:25For now, it's barely enough to wet the ground,
0:27:25 > 0:27:29but it's enough to bring the mouse lemur females out of hibernation.
0:27:43 > 0:27:47And the males are getting themselves ready for them.
0:28:01 > 0:28:05They only have one chance to mate during the entire year.
0:28:05 > 0:28:09Tonight's the night, and they can hardly wait.
0:28:15 > 0:28:19It's understandably competitive,
0:28:19 > 0:28:23these two males are fighting outside a female's tree.
0:28:37 > 0:28:40One of the males tries his luck with her.
0:28:42 > 0:28:46A swift left hook seems to make her feelings clear.
0:28:54 > 0:28:58But he persists.
0:29:10 > 0:29:13And she finally allows him in.
0:29:20 > 0:29:26The first splash of rain seems to trigger a race for everything in the Baobab forest.
0:29:26 > 0:29:30In this opportunistic place you have to move fast.
0:29:32 > 0:29:37The rain is a cue for another event that only happens on one night in the year.
0:29:39 > 0:29:43The forest floor is alive with little brown frogs.
0:29:43 > 0:29:47They have been living quietly in the forest all year.
0:29:49 > 0:29:56But when dawn breaks at the waterhole after one rainy night, an astonishing transformation has happened.
0:29:56 > 0:30:02While the females have stayed brown, all the males have turned bright yellow.
0:30:06 > 0:30:09The reason is not certain, but it might be so that the males
0:30:09 > 0:30:14and females can tell each other apart in the mass mating frenzy that follows.
0:30:23 > 0:30:30They are taking advantage of the fact that the waterhole has filled just enough to lay their eggs,
0:30:30 > 0:30:34but the rain is not yet strong enough to wash the eggs away.
0:30:34 > 0:30:37It's a very narrow window of opportunity.
0:30:43 > 0:30:50And after just a few hours, the males will all turn brown again and they'll all return to the forest.
0:30:52 > 0:30:57They won't be back to this waterhole again until this time next year.
0:30:59 > 0:31:04Although a drizzle of rain has prompted the Baobab forest to start to green,
0:31:04 > 0:31:07the lean times are not over.
0:31:07 > 0:31:13Everywhere in the forest, animals are finding their own particular ways to survive.
0:31:13 > 0:31:16Life is so challenging here that one bird
0:31:16 > 0:31:21has resorted to an extraordinary subterfuge to see her through.
0:31:21 > 0:31:27She's a vasa parrot, another Madagascar speciality.
0:31:28 > 0:31:33Inside her nest hole, this odd-looking parrot is raising a clutch of chicks.
0:31:33 > 0:31:39But she is highly promiscuous, and the chicks may have a number of different fathers.
0:31:39 > 0:31:44And she uses this fact to her advantage.
0:31:44 > 0:31:49Choosing a high perch, she belts out her song across the Baobab forest.
0:31:50 > 0:31:54PARROT SQUAWKS
0:32:04 > 0:32:06She looks somewhat scruffy.
0:32:06 > 0:32:13During the breeding season, her normally glossy black head feathers fall out, and her head turns orange.
0:32:13 > 0:32:16But she can certainly draw in the males.
0:32:24 > 0:32:28None of the males know who is the father of her chicks.
0:32:28 > 0:32:33But as she's mated with them all, they all bring her food in answer to her call.
0:32:42 > 0:32:50The feeding sessions are interspersed with gentle little head sways that seem to confirm their relationship.
0:32:50 > 0:32:56Each male feeds her, each perhaps believing that he's the father of her offspring.
0:33:17 > 0:33:24Finally, she returns to feed her chicks, having gathered food with very little effort on her own part.
0:33:24 > 0:33:27An elegant solution to difficult times.
0:33:50 > 0:33:56By December in the southern river forest, the river is at its lowest ebb.
0:33:58 > 0:34:01Oddly, it appears to be raining here,
0:34:01 > 0:34:04but it's not rain at all.
0:34:12 > 0:34:16The trees are full of large insects, cicadas,
0:34:16 > 0:34:19recently hatched and feeding on sap.
0:34:19 > 0:34:22As they feed, they squirt out honeydew.
0:34:31 > 0:34:36And for the river forest ringtails, always on the lookout for something new to eat,
0:34:36 > 0:34:38there's a feast to be had.
0:34:49 > 0:34:54But there's a problem - the cicadas are quite hard to catch.
0:35:19 > 0:35:23Cicadas are a valuable source of protein,
0:35:23 > 0:35:26but it's a lot of effort.
0:35:26 > 0:35:29And there is a much easier way to get hold of them.
0:35:33 > 0:35:37A giant wasp, the size of a small bird.
0:35:37 > 0:35:40She is a specialist in catching cicadas.
0:35:40 > 0:35:44She stings one, to paralyse it, and drags it to her underground cache.
0:35:57 > 0:36:03So all the ringtail has to do is to watch where the wasp leaves one.
0:36:13 > 0:36:17The river forest ringtails are nothing if not opportunistic.
0:36:17 > 0:36:22It's an adaptability that sees them through the worst of the southern dry season.
0:36:30 > 0:36:33Eventually, these rivers will fill.
0:36:33 > 0:36:38The brief wet season is on its way.
0:36:38 > 0:36:43It's February, the hottest time of year. And there's a change coming.
0:36:43 > 0:36:51It's the monsoon season in Madagascar, and heavy rainstorms move down the island from the north.
0:36:53 > 0:36:56Thunderclouds begin to bubble up.
0:36:56 > 0:37:02At last, after ten months of dryness, a deluge hits the Baobab forests of the west.
0:37:02 > 0:37:06THUNDER
0:37:38 > 0:37:42Trees that looked lifeless are now revived and green.
0:38:13 > 0:38:16And there has been another transformation.
0:38:16 > 0:38:21The little Labord's chameleons have grown enormously.
0:38:24 > 0:38:28This male is now five times bigger, and in full breeding colours
0:38:33 > 0:38:38and this female has become a real beauty.
0:38:45 > 0:38:48The male touches the branch with his tongue.
0:38:48 > 0:38:51He can taste that she's been that way.
0:39:02 > 0:39:08But before he can get to her, he has to fight off a rival male.
0:39:08 > 0:39:11They're all racing against time. CHAMELEON HISSES
0:39:28 > 0:39:32Their lives are so brief that they only have one chance to mate.
0:39:47 > 0:39:52He approaches her, but she seems less than keen.
0:39:54 > 0:39:58It may be that she's already mated, and is already pregnant.
0:39:59 > 0:40:01He might be too late.
0:40:04 > 0:40:06She couldn't afford to waste time.
0:40:06 > 0:40:12As soon as she's laid her eggs, she'll die, and all the males will be dead soon after.
0:40:12 > 0:40:16Their lives are lived only in the brief wet season.
0:40:16 > 0:40:20The violence of their short lives hastens their end.
0:40:22 > 0:40:25Living fast, and dying young.
0:40:25 > 0:40:30It's a radical strategy for a place where resources are low for most of the year.
0:40:47 > 0:40:52This is the richest time of year in the Baobab forest.
0:40:52 > 0:40:56In the trees above, as night falls, the Baobabs bloom...
0:40:56 > 0:40:59peculiar giant scented flowers that open in minutes.
0:41:42 > 0:41:47For the adaptable mouse lemurs, the flowers are irresistible.
0:41:58 > 0:42:03The nectar is a treat. But it also brings in moths. A double feast.
0:42:11 > 0:42:13The good times are back.
0:42:41 > 0:42:47This is the most dramatic change in all Madagascar's landscapes.
0:42:47 > 0:42:51But the rainy season will last only a few more weeks,
0:42:51 > 0:42:56and desiccation will soon return to these Baobab forests.
0:43:07 > 0:43:12But in the far south, the river forest has stayed green all year.
0:43:12 > 0:43:16The river has been its lifeblood in an arid landscape.
0:43:16 > 0:43:22Fed by fleeting rainfall, it has briefly filled, and the forest is at its richest.
0:43:24 > 0:43:28The ringtails are well-fed, and in peak condition.
0:43:34 > 0:43:38It's now April, and the babies have become independent.
0:43:38 > 0:43:43One or two may still try to hang on, but the breeding season has started again.
0:43:43 > 0:43:51It will only last for just a week or two, and each individual female will be fertile for just a few hours.
0:43:53 > 0:43:56That means that things are going to get intense.
0:44:06 > 0:44:09Border disputes among groups are common.
0:44:09 > 0:44:15They are usually settled by a totally unique way of fighting. With smell.
0:44:18 > 0:44:23The males rub the glands of their wrists on their tails and waft them at rivals...
0:44:23 > 0:44:25and that's usually enough to send them off.
0:44:25 > 0:44:29But at this time of the year, things get more competitive.
0:44:59 > 0:45:02The males also wave their perfume at females,
0:45:02 > 0:45:05hoping to persuade them to mate.
0:45:17 > 0:45:22The most powerful males will usually be the ones to mate with the females.
0:45:28 > 0:45:35But she is totally in charge, and has no hesitation in seeing him off if she's not ready.
0:45:52 > 0:46:00If she approves of him, she retreats little by little into the bushes, out of the way of other male attention.
0:46:00 > 0:46:05By the shifty look of these two, this female is mating with a male of lesser rank.
0:46:05 > 0:46:10The mating season is so short, it becomes a bit of a free for all.
0:46:21 > 0:46:24The cycle is complete.
0:46:32 > 0:46:35Further south, by April,
0:46:35 > 0:46:39the fleeting rain has finally come to the spiny forest.
0:46:47 > 0:46:53The difference is striking. This strange, tangled forest has turned green.
0:46:55 > 0:46:59But it's still as spiny.
0:47:01 > 0:47:04The sifaka infants have survived their first dry season.
0:47:06 > 0:47:10The little scraps of white fur are seven months old.
0:47:10 > 0:47:12And now there is plenty to eat.
0:47:21 > 0:47:24But even now, the season is turning.
0:47:24 > 0:47:30The greenery won't last long, and the females are already pregnant again.
0:47:30 > 0:47:34In four months new babies will be born.
0:47:37 > 0:47:42The youngsters are now independent, and must move around the forest by themselves.
0:47:42 > 0:47:48Which they do, among the vicious spines, with wild abandon and without any apparent difficulties at all.
0:47:50 > 0:47:54How they can do this without injuring themselves remains a mystery.
0:47:56 > 0:48:01But then, much of Madagascar's wildlife is still not fully understood.
0:48:56 > 0:49:00Lemurs leaping through a forest of spines.
0:49:00 > 0:49:06Nowhere else, outside this one patch in the south of the island, can such a thing be seen.
0:49:06 > 0:49:12But then, most of Madagascar's wildlife exists nowhere else in the world.
0:49:13 > 0:49:17The entire island is a hotspot of biological diversity,
0:49:17 > 0:49:23a treasure house of natural riches that is one of the most significant on earth.
0:49:23 > 0:49:30Each species has adapted in its own way to the extremes of climate and landscape.
0:49:32 > 0:49:34But many of them are under threat,
0:49:34 > 0:49:38from loss of habitat, from climate change, from hunting.
0:49:38 > 0:49:43They're the same perils that face so much of the world's wildlife.
0:49:43 > 0:49:47But here they are especially poignant.
0:49:51 > 0:49:57Madagascar is an unrepeatable experiment, a set of unique animals
0:49:57 > 0:50:02and plants evolving in isolation for over 60 million years.
0:50:02 > 0:50:05We are still trying to unravel its mysteries.
0:50:05 > 0:50:11How tragic it would be if we lost it before we even understood it.
0:50:32 > 0:50:36Of all the strange and secretive creatures there are in Madagascar,
0:50:36 > 0:50:40there is one that was the biggest challenge of all to film.
0:50:42 > 0:50:49It lives in the most remote forests, it's nocturnal, and it's very rare.
0:50:49 > 0:50:51There's something in there.
0:50:51 > 0:50:54It's also dangerous.
0:50:59 > 0:51:00It's the fossa.
0:51:04 > 0:51:09The team travelled to the dry western forest, which is the fossa's stronghold.
0:51:15 > 0:51:21Even the people living right at the edge of the forest won't venture in at night.
0:51:21 > 0:51:23TRANSLATED
0:51:37 > 0:51:40The fossa is Madagascar's most fearsome predator.
0:51:40 > 0:51:45Even the team's guide, Jean, isn't too keen.
0:51:45 > 0:51:48I'm scared of fossa even though I'm a guide here,
0:51:48 > 0:51:52since the fossa is very strong, and it may attack people.
0:51:54 > 0:51:57But the team were not to be put off.
0:51:57 > 0:52:01They were joined by scientist Mia-Lana Luers.
0:52:01 > 0:52:04She has been studying the fossa for three years,
0:52:04 > 0:52:06but even she doesn't know a great deal.
0:52:06 > 0:52:10They usually have a secretive life and it is difficult to observe them
0:52:10 > 0:52:12especially because they are mostly solitary.
0:52:15 > 0:52:19But Mia has a plan. She explains to director Emma Napper
0:52:19 > 0:52:23that she has already fitted some of the fossa with radio collars.
0:52:23 > 0:52:26Although they can't pinpoint an individual fossa,
0:52:26 > 0:52:30in the mating season the collars can reveal where they are gathering,
0:52:30 > 0:52:33around big trees where males court females.
0:52:33 > 0:52:37Jean goes in search of a likely courtship tree.
0:52:38 > 0:52:45To look for the tree where the fossa mate in this place, it's...it's hard,
0:52:45 > 0:52:49but we'll work together.
0:52:52 > 0:52:55Using Mia's data, the team head for a likely spot.
0:52:55 > 0:53:00Jean finds signs that fossa may have been using this tree for courting.
0:53:00 > 0:53:02So now the team must go into the forest at night.
0:53:17 > 0:53:21They carefully light the courting tree with infra-red lights,
0:53:21 > 0:53:25visible to a camera, but invisible to the naked eye.
0:53:25 > 0:53:28It means the team are working in the pitch dark.
0:53:33 > 0:53:36At night, the forest comes alive.
0:53:36 > 0:53:39For hours, the team listen and wait.
0:53:43 > 0:53:47Cameraman Kevin Flay heads deeper into the forest.
0:53:53 > 0:53:56The thing is, it's really really black.
0:53:56 > 0:54:00So you are just relying on your hearing all the time.
0:54:03 > 0:54:06It's pretty unnerving because you just don't know where they are.
0:54:06 > 0:54:11Just occasionally you might hear a twig break or some rustling leaves.
0:54:11 > 0:54:14These people who live in villages and they don't have torchlight,
0:54:14 > 0:54:19and they, they just hear this thing coming into their village, it must be,
0:54:19 > 0:54:21you know, it must be pretty frightening.
0:54:22 > 0:54:25I can definitely hear something moving out there.
0:54:25 > 0:54:27Then Mia hears a distant call.
0:54:29 > 0:54:32WAILING AND SCREECHING
0:54:38 > 0:54:42And then suddenly the lights go out!
0:54:46 > 0:54:49Next morning, the team find the cause.
0:54:49 > 0:54:51The lighting cable has big teeth marks in it.
0:54:51 > 0:54:56We found that the wire was broken. That was eaten by the fossa.
0:54:56 > 0:54:57It was amazing!
0:54:57 > 0:54:59And that's not all!
0:54:59 > 0:55:03The fossa tried to steal something from this bag.
0:55:03 > 0:55:10See, the fossa you know, the fossa is really clever and she eats anything, even...
0:55:10 > 0:55:11even your shoes!
0:55:13 > 0:55:18In the dry season with little to eat, it seems that fossa will have a go at anything.
0:55:26 > 0:55:30The following night, it's back into the forest.
0:55:30 > 0:55:33For several hours, there is nothing.
0:55:33 > 0:55:36But then those eerie sounds begin again.
0:55:39 > 0:55:41And suddenly, out of the darkness,
0:55:43 > 0:55:45they're right there.
0:55:51 > 0:55:57At last, the team get their first good look at these extraordinary animals.
0:56:01 > 0:56:04Through the camera they are transformed.
0:56:04 > 0:56:09Elegant, relaxed, and totally at home in the pitch black forest.
0:56:19 > 0:56:21These are two males.
0:56:21 > 0:56:24And they seem in no hurry to leave.
0:56:28 > 0:56:32And then Jean finds the reason why.
0:56:32 > 0:56:35Up in the tree there is a female.
0:56:37 > 0:56:41One of the males climbs the tree to try his luck with her.
0:56:47 > 0:56:49Eventually, they start to mate.
0:56:49 > 0:56:53And they continue their liaison until dawn.
0:56:53 > 0:56:58It's a rare chance for Kevin to capture shots of the fossa by day.
0:56:58 > 0:57:02Other males start to gather around the mating tree...
0:57:02 > 0:57:05it's an astonishing sight.
0:57:16 > 0:57:22Thanks to the night filming, Mia has learnt a little more about their behaviour.
0:57:22 > 0:57:24But she's concerned.
0:57:27 > 0:57:30Her data shows that this huge forest
0:57:30 > 0:57:36may only have ten females left in it, and that's not nearly enough.
0:57:36 > 0:57:42This beautiful and enigmatic creature may be critically endangered, and yet we still know so little about it.
0:57:42 > 0:57:48As with so much of Madagascar's wildlife, the challenge will be to discover more
0:57:48 > 0:57:50before it's too late.
0:58:10 > 0:58:13Subtitles by Red Bee Media Ltd
0:58:13 > 0:58:16E-mail subtitling@bbc.co.uk