0:00:03 > 0:00:07'Created by fire and titanic upheavals of the earth,
0:00:07 > 0:00:11'islands make up one sixth of the landmass of our planet.
0:00:12 > 0:00:15'They are lenses through which to study
0:00:15 > 0:00:18'the complex workings of evolution.'
0:00:18 > 0:00:21Tropical islands have been important
0:00:21 > 0:00:23in the understanding of evolution
0:00:23 > 0:00:26ever since Charles Darwin visited the Galapagos
0:00:26 > 0:00:28early in the 19th century.
0:00:28 > 0:00:31We are going to visit three very different tropical islands
0:00:31 > 0:00:35to see what they can tell us about evolution, even today.
0:00:37 > 0:00:39'Islands are natural laboratories.
0:00:41 > 0:00:44'Full of novel experiments in natural selection...
0:00:45 > 0:00:47'..and evolutionary wonders.'
0:00:49 > 0:00:54But there's much more to evolution than the survival of the fittest.
0:00:54 > 0:00:56The phrase wasn't even in Darwin's first edition
0:00:56 > 0:00:58of the Origin of Species.
0:01:00 > 0:01:03'I'm exploring other major influences.
0:01:03 > 0:01:06'Geology, geography.'
0:01:07 > 0:01:10Hello! 'Isolation and time.'
0:01:10 > 0:01:14- You found this?- Yeah.- Giant's bones!
0:01:14 > 0:01:17'I'll be charting the lifecycle of islands.
0:01:18 > 0:01:20'From birth and colonisation...
0:01:21 > 0:01:23'..to the burst of evolutionary creativity
0:01:23 > 0:01:25'that often accompanies maturity.'
0:01:27 > 0:01:29(They take the leaves so delicately.)
0:01:30 > 0:01:35'And what eventually happens when an island grows old and nears its end.'
0:01:35 > 0:01:38You can almost feel this unforgiving rock
0:01:38 > 0:01:41return ultimately to sea level.
0:01:41 > 0:01:44'Places of extinction, as well as creation.
0:01:46 > 0:01:49'Our story will reveal evolution in action.'
0:01:50 > 0:01:54We just discovered a new species of the mouse lemurs.
0:01:54 > 0:01:57- So, mouse lemurs are still actively evolving?- Yeah.
0:01:58 > 0:02:03'And how life generates abundance, even from a blank slate.'
0:02:06 > 0:02:08Islands are the ideal place
0:02:08 > 0:02:11to understand the rules that govern evolution.
0:02:31 > 0:02:34'Madagascar is an island of great antiquity,
0:02:34 > 0:02:39'where the aeons have created almost a separate realm of animals.
0:02:41 > 0:02:44'Of the 250,000 species that live here,
0:02:44 > 0:02:47'more than 90% of the island's amphibians,
0:02:47 > 0:02:51'70% of its reptiles and plants,
0:02:51 > 0:02:53'as well as half its birds,
0:02:53 > 0:02:57'and almost all of its spiders and insects, are endemic.
0:02:58 > 0:03:01'Natives that are found here and nowhere else.
0:03:06 > 0:03:11'To solve the riddle of how such extraordinary diversity was created,
0:03:11 > 0:03:14'I first need to see one of its most charismatic animals.'
0:03:21 > 0:03:24Animals whose ancestors arrived here
0:03:24 > 0:03:29probably on a natural raft of vegetation some 55 million years ago.
0:03:30 > 0:03:35Primates related to modern monkeys, apes and even us.
0:03:37 > 0:03:39The lemurs.
0:03:41 > 0:03:46The ancestral lemur survived crossing several hundred miles of ocean
0:03:46 > 0:03:50to find itself marooned on a nearly uninhabited island.
0:03:54 > 0:03:57The fourth-largest island in the world, Madagascar,
0:03:57 > 0:04:01is 250 miles off the east coast of Africa.
0:04:01 > 0:04:05A thousand miles long and 350 miles at its widest point.
0:04:09 > 0:04:11'Descendants of the first primates
0:04:11 > 0:04:13'that landed all those millions of years ago
0:04:13 > 0:04:16'can be found on a series of smaller islands
0:04:16 > 0:04:18'set within a Madagascan river.
0:04:21 > 0:04:24'But these islands are not all they seem.'
0:04:26 > 0:04:30It looks like a jungle, it smells like a jungle
0:04:30 > 0:04:35and it is a jungle of sorts - but a bogus jungle.
0:04:38 > 0:04:40Welcome to Lemur Island.
0:04:40 > 0:04:43Not quite a zoo, but it certainly ain't natural.
0:04:51 > 0:04:52Hello, little guy.
0:04:56 > 0:05:00'Just a short paddle across the manmade river,
0:05:00 > 0:05:02'tourists from the nearby private lodge
0:05:02 > 0:05:04'can get up close and personal
0:05:04 > 0:05:07'with as many as six captive lemur species
0:05:07 > 0:05:10'from different parts of Madagascar.'
0:05:10 > 0:05:12THEY LAUGH
0:05:24 > 0:05:26Well, he's looking around for the next banana.
0:05:26 > 0:05:28I'm just a passing fad.
0:05:34 > 0:05:36The lemurs' exile in Madagascar
0:05:36 > 0:05:38has favoured the retention of traits
0:05:38 > 0:05:41some other primates have left behind.
0:05:42 > 0:05:45Lemurs are different from monkeys.
0:05:45 > 0:05:49Lemurs are related to bushbabies...and lorises.
0:05:49 > 0:05:54And, like them, they have a nose which sort of glistens.
0:05:54 > 0:05:56They're called strepsirrhini.
0:05:56 > 0:06:00For these particular primates, the sense of smell is all-important.
0:06:01 > 0:06:05Whereas for the monkeys and the apes, and indeed ourselves,
0:06:05 > 0:06:10we've rather relegated smell to a secondary position
0:06:10 > 0:06:13and we rely on our sight, on our wonderful vision.
0:06:14 > 0:06:18It's likely that the moist-nosed animals evolved first.
0:06:18 > 0:06:21And it's generally thought, of course,
0:06:21 > 0:06:24that these animals are a more primitive, or basal group.
0:06:29 > 0:06:33The ancestors of the lemurs arrived on Madagascar around ten million
0:06:33 > 0:06:35years after the mass extinction event
0:06:35 > 0:06:38that wiped out the dinosaurs and many other animals.
0:06:42 > 0:06:46The island they found almost completely lacked predators,
0:06:46 > 0:06:49or indeed competitors, and was richly endowed with different habitats.
0:06:51 > 0:06:54Adapting to these new circumstances
0:06:54 > 0:06:57triggered the evolution of many specialist species.
0:06:59 > 0:07:03'Today, there are no fewer than 106 species of lemurs.
0:07:05 > 0:07:09'That's almost as many as all the species of monkeys
0:07:09 > 0:07:11'living in Africa and Asia combined.
0:07:12 > 0:07:16'Biologists call this process adaptive radiation.
0:07:16 > 0:07:18'And it's a particular feature of island life,
0:07:18 > 0:07:22'where isolation creates an abundance of opportunities.'
0:07:29 > 0:07:32This really beautiful animal
0:07:32 > 0:07:35is the diademed sifaka.
0:07:38 > 0:07:41One of a dozen species in Madagascar.
0:07:46 > 0:07:49All these lemurs seem to have a different livery
0:07:49 > 0:07:52to help them recognise their own kind.
0:07:54 > 0:07:58'Sifaka lemurs feed primarily on leaves.
0:07:58 > 0:08:03'Their specially evolved stomachs can process deadly alkaloids
0:08:03 > 0:08:06'most other primates would strenuously avoid.'
0:08:14 > 0:08:16To see the largest living lemurs
0:08:16 > 0:08:19produced by this burst of adaptive evolution,
0:08:19 > 0:08:23I visit the remote Mitsinjo Forest Reserve.
0:08:26 > 0:08:31I'm with Dr Rainer Dolch and guide Regis Razafiarison
0:08:31 > 0:08:35who have spent much of the last 20 years trying to protect them.
0:08:37 > 0:08:40I'm in this fragment of Madagascan rainforest
0:08:40 > 0:08:42in search of a large lemur
0:08:42 > 0:08:44that doesn't really respond to being kept in captivity.
0:08:44 > 0:08:47You just have to examine it in the wild.
0:08:50 > 0:08:53Indri live in troops of six to eight individuals
0:08:53 > 0:08:55led by a dominant female.
0:09:00 > 0:09:04Their song is the most complex of all lemur species,
0:09:04 > 0:09:07which not only marks out their territory for neighbouring groups,
0:09:07 > 0:09:10but is used for warnings and bonding.
0:09:11 > 0:09:13LEMURS CALL
0:09:14 > 0:09:16- Do you hear that wailing sound over there?- Yeah.
0:09:16 > 0:09:19- Yeah, it's distant. Yeah. - Yeah, so I think we're fairly close.
0:09:19 > 0:09:21That's their territorial call,
0:09:21 > 0:09:25and I think we just move that direction, and...
0:09:25 > 0:09:26try and find the group.
0:09:35 > 0:09:38- There...- Lovely view. Lovely view.
0:09:41 > 0:09:43So, do you see the two?
0:09:43 > 0:09:45One's a bit further down.
0:09:45 > 0:09:46Yeah, yeah.
0:09:48 > 0:09:51But it's usually the female that leads the calls.
0:09:54 > 0:09:56And it's a surprisingly effective call
0:09:56 > 0:09:59- that carries a long distance, doesn't it?- It does, yeah.
0:09:59 > 0:10:03You can hear it even in the village, which is like 3km away from here,
0:10:03 > 0:10:09so they delineate their territory by calling every morning.
0:10:09 > 0:10:12So, they distinguish themselves from other bands.
0:10:12 > 0:10:14They distinguish themselves from other bands -
0:10:14 > 0:10:16but they're also communicating within the group,
0:10:16 > 0:10:19because at some point the group will actually be spread out
0:10:19 > 0:10:22quite...over a large area.
0:10:25 > 0:10:30The indri has evolved to feed on a wide variety of leaves and flowers
0:10:30 > 0:10:33only found in the ancient Malagasy rainforest.
0:10:37 > 0:10:39Rainer and his team
0:10:39 > 0:10:43have been monitoring this particular family for several years now.
0:10:43 > 0:10:46To see if he can get us a little bit closer,
0:10:46 > 0:10:50Regis has brought them some of their favourite leaves.
0:10:50 > 0:10:53We try to tempt them down and lure them towards us,
0:10:53 > 0:10:56if you like, and - well, let's see what comes out of it,
0:10:56 > 0:10:58but Regis has done that for quite some time,
0:10:58 > 0:11:01so we can just trust him and follow him.
0:11:25 > 0:11:26And it's coming.
0:11:26 > 0:11:28There you go.
0:11:43 > 0:11:44Beautifully versatile hands,
0:11:44 > 0:11:48forward-looking eyes, and so on, that reveal...it's primate.
0:11:48 > 0:11:51Yeah, totally. I mean, the hands, if you look at them,
0:11:51 > 0:11:53they are quite humanlike.
0:11:55 > 0:11:58We can also see this delicate way of nibbling leaves,
0:11:58 > 0:12:00- so it's...it's a leaf connoisseur.- Yeah.
0:12:04 > 0:12:06Could I have a closer look myself?
0:12:06 > 0:12:08Sure, yeah. Let's approach them a bit.
0:12:21 > 0:12:23(They take the leaves so delicately.)
0:12:32 > 0:12:39Malagasy legends revere the indri as man's closest relative,
0:12:39 > 0:12:43the long lost brother who still dwells in the forest.
0:12:52 > 0:12:54The indri has evolved a specialised diet
0:12:54 > 0:12:58that requires it to forage over large areas,
0:12:58 > 0:13:01restricting the places it can live and limiting its numbers...
0:13:07 > 0:13:11..but no such limits apply to my next lemur.
0:13:11 > 0:13:14A small generalist whose rapid evolution
0:13:14 > 0:13:18has allowed it to spread to different habitats all over the island.
0:13:23 > 0:13:29To see one, I travel to the botanical gardens and zoo of Tsimbazaza...
0:13:32 > 0:13:34..and meet Madagascar's leading primatologist.
0:13:36 > 0:13:38I'm with Professor Jonah Ratsimbazafy,
0:13:38 > 0:13:41and we're looking at the mouse lemur,
0:13:41 > 0:13:45the smallest of all living lemurs -
0:13:45 > 0:13:47and, indeed, the smallest primate.
0:13:47 > 0:13:52Well, Jonah, the great bulbous eyes mean - certainly nocturnal.
0:13:52 > 0:13:56Exactly. They are very, very dynamic when it's dark.
0:13:56 > 0:13:59They look as if they've got kind of those insectivore faces.
0:13:59 > 0:14:02Yes. They eat mostly insects.
0:14:02 > 0:14:05That's where they can find animal protein.
0:14:05 > 0:14:07And how long do they live?
0:14:07 > 0:14:11Most lemurs can live up to 15 years.
0:14:11 > 0:14:13So they're... For an animal of that size,
0:14:13 > 0:14:15that's quite extraordinary, isn't it?
0:14:15 > 0:14:17What does it weigh? I mean, what is...?
0:14:17 > 0:14:21The smallest mouse lemurs weigh only 30g.
0:14:21 > 0:14:23Oh!
0:14:24 > 0:14:28'Even though this mouse lemur looks like other mouse lemurs,
0:14:28 > 0:14:33'in fact, it is a recently evolved, distinct species.'
0:14:33 > 0:14:36The other interesting thing that's recently been discovered
0:14:36 > 0:14:37about these sorts of lemurs
0:14:37 > 0:14:40- is there are more species than we thought.- Yeah.
0:14:40 > 0:14:42In the past, we just thought
0:14:42 > 0:14:46that there are only two species of mouse lemurs,
0:14:46 > 0:14:51but we just discovered new species of the mouse lemurs -
0:14:51 > 0:14:53and this is one that we discovered.
0:14:53 > 0:14:56So, this is because the genetics, the genome of the species,
0:14:56 > 0:14:58- is different...- Exactly.
0:14:58 > 0:15:00..even though the appearance is superficially very similar.
0:15:00 > 0:15:03Yeah. There are more than 20 different mouse lemurs
0:15:03 > 0:15:05in the island of Madagascar.
0:15:05 > 0:15:06And are they only found in the rainforest,
0:15:06 > 0:15:09or can they survive in the cleared forests?
0:15:09 > 0:15:12Mouse lemur you can find all over Madagascar.
0:15:12 > 0:15:15So, they're actually very adaptable little animals.
0:15:15 > 0:15:18They can adapt very, very easily in their natural habitat.
0:15:23 > 0:15:26One of the reasons for the success of the lemurs
0:15:26 > 0:15:28is the rarity of predators...
0:15:29 > 0:15:32..but ancestors of one major carnivore
0:15:32 > 0:15:34managed to reach the island from Africa
0:15:34 > 0:15:36before humans arrived.
0:15:36 > 0:15:38The fossa.
0:15:39 > 0:15:42It is both very rare and very shy,
0:15:42 > 0:15:45and, in the wild, ranges over wide territories.
0:15:47 > 0:15:50In captivity, its young are so naturally ferocious
0:15:50 > 0:15:54they can only be fed live food.
0:16:23 > 0:16:25The top predator, the fossa,
0:16:25 > 0:16:30is quite capable of chasing after lemurs...
0:16:30 > 0:16:32in the canopy, as well as birds.
0:16:34 > 0:16:37It has a very catlike appearance, perhaps -
0:16:37 > 0:16:39particularly with its long balancing tail -
0:16:39 > 0:16:42but actually it is related to the mongoose,
0:16:42 > 0:16:45which, of course, is an African neighbour.
0:16:48 > 0:16:50It's really quite a fearsome predator.
0:16:55 > 0:16:59The fossa's long tail make it extremely well-adapted
0:16:59 > 0:17:00to hunting in the trees...
0:17:02 > 0:17:07..but Madagascar's predators come in unexpected shapes and sizes.
0:17:08 > 0:17:10This small chameleon
0:17:10 > 0:17:13belongs to one of the oldest and most diverse
0:17:13 > 0:17:15radiations of animals on the island.
0:17:16 > 0:17:19So, look at this little chap, here.
0:17:20 > 0:17:23It's a small Calumma gastrotaenia.
0:17:24 > 0:17:26Just woke up.
0:17:26 > 0:17:29So, walking slowly - but they always walk slowly.
0:17:29 > 0:17:30They always walk slowly,
0:17:30 > 0:17:34and it always seems that they do two steps forward and one step back.
0:17:34 > 0:17:38That's obviously a camouflage against predators,
0:17:38 > 0:17:41because they look like leaves moving in the wind.
0:17:42 > 0:17:46Now, Madagascar's really the home of the chameleon, isn't it?
0:17:46 > 0:17:47That's true.
0:17:47 > 0:17:49I mean, you find more than half
0:17:49 > 0:17:53of all the chameleon species of the world in Madagascar.
0:17:53 > 0:17:56It really has developed from the north to the south -
0:17:56 > 0:17:58from the rainforest to the dry forest.
0:17:58 > 0:17:59If you're small, like this chap,
0:17:59 > 0:18:02you obviously go for really small flies, or small crickets,
0:18:02 > 0:18:06or something like that, as your prey.
0:18:07 > 0:18:11This tiny chameleon weighs only a few grams.
0:18:13 > 0:18:14Like this cricket,
0:18:14 > 0:18:19it would also provide a tasty morsel for its largest relative -
0:18:19 > 0:18:24just one of the 75 different species on Madagascar.
0:18:24 > 0:18:29So, we've seen the smallest, and this must be - what? The largest?
0:18:29 > 0:18:32This is one of the two largest chameleon species
0:18:32 > 0:18:35in Madagascar - and the world.
0:18:35 > 0:18:37This is Parson's chameleon
0:18:37 > 0:18:42and it's actually named after a parson, as you may have imagined -
0:18:42 > 0:18:45actually a missionary that worked in Madagascar in the 19th century.
0:18:45 > 0:18:49So, it can grow a bit bigger than it is at the moment,
0:18:49 > 0:18:52but that's already an impressive animal.
0:18:57 > 0:19:00And does he live high in the canopy?
0:19:00 > 0:19:02Lives high in the canopy,
0:19:02 > 0:19:04and up there it feeds on large insects
0:19:04 > 0:19:06such as dragonflies or large crickets,
0:19:06 > 0:19:08and, well, eventually other chameleons
0:19:08 > 0:19:10that are smaller than him.
0:19:13 > 0:19:17When I first looked at these things, I thought they've only got two toes -
0:19:17 > 0:19:20but then I saw, INSIDE...
0:19:20 > 0:19:22I could see the bones of the normal fingers.
0:19:22 > 0:19:24Five toes, but bundled up.
0:19:25 > 0:19:29Well, those toes are an adaptation to arboreal life,
0:19:29 > 0:19:33and so that gives them a shape of their feet
0:19:33 > 0:19:37with which they can actually grab the branches they're walking on -
0:19:37 > 0:19:40just, like, look at it, how it can suspend itself,
0:19:40 > 0:19:42like, just clinging on my arm.
0:19:46 > 0:19:49But not all chameleons live in trees.
0:19:52 > 0:19:57Unlike the lemurs, whose original ancestor has long vanished,
0:19:57 > 0:20:00the relatively primitive chameleon settlers
0:20:00 > 0:20:04still live alongside more recently evolved ascendants.
0:20:04 > 0:20:06Look what we have here.
0:20:06 > 0:20:08- Do you see?- Wow!- The animal sitting on the leaf there.
0:20:08 > 0:20:09What a handsome fellow.
0:20:12 > 0:20:15Looks like a minute triceratops dinosaur.
0:20:16 > 0:20:20So, is this the horned chameleon, with its pair of horns at the front?
0:20:20 > 0:20:23It's actually called the Brookesia superciliaris,
0:20:23 > 0:20:27so the horns are a bit reminiscent of giant eyebrows.
0:20:27 > 0:20:28- Oh, right!- That's the name.
0:20:28 > 0:20:31But it's on the ground, of course. It's not on the branches.
0:20:31 > 0:20:32It is a ground chameleon,
0:20:32 > 0:20:36so it would actually go on the forest floor during daytime
0:20:36 > 0:20:38and forage, and then only at night
0:20:38 > 0:20:40would he climb up on small branches to go to sleep.
0:20:40 > 0:20:43And you say it's a relatively primitive one.
0:20:43 > 0:20:47It is a very basal chameleon on the chameleon phylogenetic tree.
0:20:47 > 0:20:51So, that means that ground hunting probably came before arboreal hunting
0:20:51 > 0:20:53for these animals.
0:20:53 > 0:20:54So, what we're seeing here
0:20:54 > 0:20:58- is the sort of basal part of an evolutionary radiation.- That's right.
0:20:58 > 0:21:01But instead of the species dying out, as you might expect,
0:21:01 > 0:21:03they're all still with us.
0:21:05 > 0:21:07An evolutionary scenario
0:21:07 > 0:21:11that allows both ancient and recent forms of related animals
0:21:11 > 0:21:14to live alongside one another is rather unusual.
0:21:16 > 0:21:19What allowed this to happen on Madagascar?
0:21:19 > 0:21:21The answer is time.
0:21:28 > 0:21:3380% of all islands in oceans are created by volcanoes
0:21:33 > 0:21:37rising up from the sea floor in just a few million years.
0:21:40 > 0:21:42Madagascar is different.
0:21:42 > 0:21:46It was born when the ancient supercontinent of Gondwana
0:21:46 > 0:21:50was pulled apart by the inexorable forces of plate tectonics
0:21:50 > 0:21:53200 million years ago.
0:21:53 > 0:21:59By 90 million years ago, Madagascar had been transformed into an island.
0:22:10 > 0:22:14This massive rock is granite,
0:22:14 > 0:22:17and the presence of granite is proof enough
0:22:17 > 0:22:23that Madagascar was once part of an ancient continent.
0:22:23 > 0:22:28It's an "acid rock", as geologists say, full of quartz.
0:22:31 > 0:22:34And, where granite weathers in a tropical climate,
0:22:34 > 0:22:38it does so to a red material called laterite,
0:22:38 > 0:22:40and in the rainy season,
0:22:40 > 0:22:45the rivers run almost red as blood as laterite is washed out.
0:22:51 > 0:22:55Millions of years of erosion from weathering and rivers
0:22:55 > 0:22:57have created numerous habitats...
0:22:59 > 0:23:02..and this great variety has in turn created a vast number
0:23:02 > 0:23:05of different ecological niches,
0:23:05 > 0:23:07providing many opportunities
0:23:07 > 0:23:10for different species to adapt and evolve.
0:23:14 > 0:23:17One way to envisage an ecological niche
0:23:17 > 0:23:22is to imagine dividing up a habitat into different packages.
0:23:22 > 0:23:26Each package or niche can be differentiated from the others
0:23:26 > 0:23:30by such factors as the amount of sunlight or rainfall it receives,
0:23:30 > 0:23:33the resources it can provide, and, crucially,
0:23:33 > 0:23:37whether it is already occupied by other potential competitors.
0:23:40 > 0:23:42In Madagascar's rainforest,
0:23:42 > 0:23:45frogs have occupied numerous special niches,
0:23:45 > 0:23:48partly because they're the only amphibians
0:23:48 > 0:23:50to have colonised the island.
0:23:50 > 0:23:52Toads and newts never made it.
0:23:56 > 0:24:00At the Amphibian Survival Assurance Center of Andasibe,
0:24:00 > 0:24:03scientists are trying to discover more
0:24:03 > 0:24:07about Madagascar's numerous species of endemic frogs.
0:24:07 > 0:24:09Come on in.
0:24:09 > 0:24:11Oh, wow. So this is your...
0:24:12 > 0:24:13..frog heaven.
0:24:13 > 0:24:15That's not the right term...
0:24:15 > 0:24:17'To protect them from invasive diseases,
0:24:17 > 0:24:21'Dr Devin Edmonds heads a captive breeding programme.'
0:24:21 > 0:24:23Well, I'm looking for the frogs.
0:24:23 > 0:24:24THEY CHUCKLE
0:24:24 > 0:24:28I can't actually spot one, but you'll no doubt...
0:24:28 > 0:24:30- Oh, yes, I can - right in the middle there.- Yeah.
0:24:32 > 0:24:35Tiny brown frog with a tiny white spot on its nose.
0:24:37 > 0:24:41'His research vividly demonstrates how separation of populations
0:24:41 > 0:24:45'might trigger the appearance of new species.'
0:24:47 > 0:24:52We have one species here that looks almost identical
0:24:52 > 0:24:56to another in our forest that we have here.
0:24:56 > 0:24:58The only way to really tell the two apart
0:24:58 > 0:25:01is to listen to the calls of the males.
0:25:01 > 0:25:04And that's quite sufficient to keep the two species absolutely separate.
0:25:04 > 0:25:08Presumably you proved that by molecular studies, as well.
0:25:08 > 0:25:10Yes, exactly. Exactly.
0:25:10 > 0:25:13So...and how recently was this recognised?
0:25:13 > 0:25:15In the last decade -
0:25:15 > 0:25:17and the species with the different call
0:25:17 > 0:25:21that looks the same as this one is not even described yet.
0:25:21 > 0:25:25- You mean... So it doesn't have a scientific name?- It doesn't.
0:25:25 > 0:25:30So, we're watching the very birth of new endemic species here.
0:25:30 > 0:25:31Yes, exactly.
0:25:31 > 0:25:34This represents kind of a complex of species.
0:25:34 > 0:25:37I think there's more than eight or nine now
0:25:37 > 0:25:40that are kind of recognised as being different species
0:25:40 > 0:25:41in different parts of the island -
0:25:41 > 0:25:44but they all essentially look like this.
0:25:46 > 0:25:48Fossil evidence of frogs
0:25:48 > 0:25:52dates back to when Madagascar was still part of Gondwana,
0:25:52 > 0:25:55and when giant reptiles still ruled the earth.
0:25:56 > 0:26:01There are more than 300 species of endemic frogs in Madagascar.
0:26:01 > 0:26:05Many of them tiny - like the ones we've looked at -
0:26:05 > 0:26:07but some slightly larger.
0:26:07 > 0:26:09But the largest frog that ever lived
0:26:09 > 0:26:12was also found in Madagascar as a fossil -
0:26:12 > 0:26:14a contemporary of the dinosaurs.
0:26:14 > 0:26:17It was 16 inches across,
0:26:17 > 0:26:20probably weighed more than 4kg,
0:26:20 > 0:26:22and some people think
0:26:22 > 0:26:26it probably ate baby dinosaurs.
0:26:28 > 0:26:33Beelzebufo's disappearance shows the isolation offered by an island
0:26:33 > 0:26:36is no guarantee of long-term survival.
0:26:37 > 0:26:40Fears of another wave of extinction
0:26:40 > 0:26:45are the reason why the survival centre in Andasibe was established.
0:26:47 > 0:26:50Devin's team conduct regular nocturnal surveys,
0:26:50 > 0:26:53capturing and swabbing local species
0:26:53 > 0:26:56to test for the presence of a new invasive disease,
0:26:56 > 0:26:58chichrid.
0:26:59 > 0:27:01It's a deadly fungus
0:27:01 > 0:27:05which some predict could make a third of the world's amphibians extinct.
0:27:09 > 0:27:14But what no-one yet knows is whether Madagascar's endemic frogs
0:27:14 > 0:27:18will be more or less vulnerable to it than those found elsewhere.
0:27:18 > 0:27:21The disease can't be removed from the environment
0:27:21 > 0:27:22once it's introduced.
0:27:22 > 0:27:25If we're not looking for it, we won't know if it arrives.
0:27:28 > 0:27:32And at the worst case scenario, you can lose a third or more
0:27:32 > 0:27:34of the amphibians in a pristine habitat
0:27:34 > 0:27:39over the course of a few months, so it can be pretty dramatic,
0:27:39 > 0:27:42or have a pretty dramatic effect on the forest -
0:27:42 > 0:27:46especially in areas where there's a lot of diversity, like Madagascar.
0:27:51 > 0:27:55An animal that shares the tree-living niche of many of Madagascar's frogs
0:27:55 > 0:27:58is lurking in the rainforest...
0:27:59 > 0:28:03..but it has evolved a strikingly different specialisation
0:28:03 > 0:28:05to survive in the dense forest.
0:28:08 > 0:28:10So, Richard, on this tree,
0:28:10 > 0:28:13some of the guides pointed out to me earlier,
0:28:13 > 0:28:15that there is a very interesting animal
0:28:15 > 0:28:17sitting on that particular tree.
0:28:17 > 0:28:20- You mean that little thin tree? - Exactly.
0:28:20 > 0:28:24So well camouflaged that it is the same colour as the bark.
0:28:24 > 0:28:27Right, well, I'll start looking at the bottom and I'll work my way up.
0:28:27 > 0:28:29- Yeah.- Ah...
0:28:29 > 0:28:31So, up...
0:28:32 > 0:28:33Are you going to give me a hint?
0:28:33 > 0:28:38Do you see the point where this branch is sticking out of the stem?
0:28:38 > 0:28:40I can see...
0:28:40 > 0:28:41Ah, I think I've finally twigged.
0:28:41 > 0:28:42If I can just...
0:28:42 > 0:28:44I point it out to you.
0:28:44 > 0:28:46- It's head-down. - Its head pointing down.
0:28:48 > 0:28:50- Yeah!- There you go.
0:28:50 > 0:28:56Well, that wins the prize, really, doesn't it? For camouflage.
0:28:56 > 0:29:01It's a leaf-tail gecko, actually, and it's another Madagascar endemic,
0:29:01 > 0:29:04and it's so well-camouflaged because if it wasn't,
0:29:04 > 0:29:06then a lot of birds would prey on it...
0:29:08 > 0:29:12..and so it would actually stay on the tree while camouflaged.
0:29:12 > 0:29:13Absolutely motionless.
0:29:13 > 0:29:15Totally.
0:29:17 > 0:29:20So, I guess these geckos have had their own radiation here.
0:29:20 > 0:29:22Did they come over, do you think,
0:29:22 > 0:29:25about the same time as the lemurs - 14 million years ago-ish?
0:29:25 > 0:29:28Yeah, that's very probable, because they must have come
0:29:28 > 0:29:30when the ocean currents permitted them to raft over
0:29:30 > 0:29:32from mainland Africa.
0:29:32 > 0:29:34That was presumably after the big extinction
0:29:34 > 0:29:37- that removed the dinosaurs - and a lot else.- That's right.
0:29:37 > 0:29:38So, they are reptiles
0:29:38 > 0:29:41that came after the dinosaurs went already extinct.
0:29:41 > 0:29:45And then took off onto their own little Madagascan radiation.
0:29:45 > 0:29:47That's right - and all the gecko species
0:29:47 > 0:29:49that we have in Madagascar are actually endemic.
0:29:49 > 0:29:51I love it.
0:29:53 > 0:29:55And once night falls,
0:29:55 > 0:30:01our once-invisible gecko wakes up to become a formidable insect hunter.
0:30:06 > 0:30:08One of the endemic insects it preys on
0:30:08 > 0:30:11has evolved features seen here on Madagascar
0:30:11 > 0:30:13and nowhere else.
0:30:14 > 0:30:18To claim its mate, it really sticks its neck out.
0:30:18 > 0:30:22One of the most extraordinary creatures,
0:30:22 > 0:30:24if most diminutive, in Madagascar.
0:30:29 > 0:30:33It's the giraffe-necked weevil.
0:30:38 > 0:30:40It's the male -
0:30:40 > 0:30:44and only the male has this extraordinary extended neck,
0:30:44 > 0:30:50and it's not surprising to learn that it's used to battle other males.
0:30:50 > 0:30:52The one with the longest and strongest
0:30:52 > 0:30:56wins the attentions of the female, which has no such long neck.
0:30:56 > 0:30:58It's a very special kind of adaptation.
0:31:02 > 0:31:04The female has a short, stubby neck
0:31:04 > 0:31:06and rolls up the leaf of its favourite food plant
0:31:06 > 0:31:08into a sort of cylinder and lays its egg there.
0:31:08 > 0:31:12The cylinder falls to the ground, and the next generation is nourished.
0:31:12 > 0:31:13Of course, it's a beetle,
0:31:13 > 0:31:18so it has wings that are folded under the scarlet wing cases,
0:31:18 > 0:31:19and it's quite capable of flying off -
0:31:19 > 0:31:24in fact, I can see it flexing its wing cases even as I speak.
0:31:26 > 0:31:28It's probably searching a male to fight,
0:31:28 > 0:31:30or maybe a female to mate with.
0:31:39 > 0:31:42Most colonists that arrive on a remote island like Madagascar,
0:31:42 > 0:31:44full of opportunities,
0:31:44 > 0:31:47have ample space to radiate and evolve,
0:31:47 > 0:31:51becoming the forebears of many new species...
0:31:55 > 0:31:56Ooh...
0:31:57 > 0:31:58Aha! I can see it.
0:32:00 > 0:32:04..but sometimes a plant or animal breaks this general rule.
0:32:09 > 0:32:14Eddy Manatijara is searching for an epiphyte -
0:32:14 > 0:32:17a plant that grows harmlessly on another plant.
0:32:20 > 0:32:24It favours inaccessibly high tree branches.
0:32:29 > 0:32:32Yet despite having such an elevated niche high in the canopy,
0:32:32 > 0:32:36this plant's status is more akin to that of a fugitive.
0:32:38 > 0:32:41'Because, in the game of radiating into new niches...'
0:32:41 > 0:32:43A special treasure.
0:32:43 > 0:32:45'..it did not pass go.'
0:32:46 > 0:32:47Bit more.
0:32:49 > 0:32:52What may not look the most exciting of plants...
0:32:53 > 0:32:57It's a cactus, and it's called rhipsalis,
0:32:57 > 0:33:01and it's the only cactus in Madagascar.
0:33:01 > 0:33:04Other species of rhipsalis
0:33:04 > 0:33:08are found, for example, on the southern part of India.
0:33:08 > 0:33:12So, this is a relic of the ancient Gondwana continent.
0:33:13 > 0:33:16But it's also interesting from another point of view -
0:33:16 > 0:33:22we're used by now to seeing radiations in Madagascar.
0:33:22 > 0:33:25Different groups of animals and plants
0:33:25 > 0:33:27filling a whole range of ecological niches
0:33:27 > 0:33:30and producing lots and lots of species.
0:33:30 > 0:33:32The cacti didn't do it -
0:33:32 > 0:33:36so this, you could say, is the exception that proves the rule.
0:33:39 > 0:33:43The cactus's failure to radiate left many of the dry habitat niches,
0:33:43 > 0:33:46which have been occupied by cacti elsewhere,
0:33:46 > 0:33:48free for other plants to exploit.
0:33:50 > 0:33:52But in order to adapt to these habitats,
0:33:52 > 0:33:55many of these plants in turn became very cactus-like,
0:33:55 > 0:33:57resembling this euphorbia.
0:34:02 > 0:34:05It's a process called convergent evolution.
0:34:09 > 0:34:12Having spent four decades studying the history of life
0:34:12 > 0:34:14since the earliest times,
0:34:14 > 0:34:17there is something particularly fascinating
0:34:17 > 0:34:20about seeing how nature keeps reinventing the same traits
0:34:20 > 0:34:21in different organisms.
0:34:27 > 0:34:30These are giant pill millipedes.
0:34:31 > 0:34:34It's a particularly wonderful animal for me to find,
0:34:34 > 0:34:38because it reminds me very much of the trilobites I studied
0:34:38 > 0:34:40for so many years at the Natural History Museum -
0:34:40 > 0:34:44many of which could also roll into a tight ball...
0:34:44 > 0:34:46just like this animal.
0:34:46 > 0:34:48He's not very frightened of me, though, because...
0:34:48 > 0:34:51he's unrolling almost immediately!
0:34:51 > 0:34:54There you can see the legs on the underside...
0:34:54 > 0:34:56kicking away, you see?
0:34:59 > 0:35:05Well, I've seen animals more than 400 million years old
0:35:05 > 0:35:07that look remarkably similar.
0:35:07 > 0:35:12So, for me, I'm looking back hundreds of millions of years into the past,
0:35:12 > 0:35:17even though these animals probably evolved here...
0:35:17 > 0:35:22Well, I'd say "only" a few tens of millions of years ago.
0:35:22 > 0:35:25Of course, there's no question of these being other than
0:35:25 > 0:35:28the most distantly related, in that they're both arthropods.
0:35:28 > 0:35:34It just shows that common problems promote rather similar solutions.
0:35:36 > 0:35:41Another example of convergent evolution.
0:35:41 > 0:35:43Aren't they wonderful?
0:35:48 > 0:35:51My next example of convergent evolution
0:35:51 > 0:35:53is a nocturnal wanderer.
0:35:58 > 0:35:59Quite spooky.
0:36:05 > 0:36:06There's a...
0:36:06 > 0:36:09There's a family of woolly lemurs,
0:36:09 > 0:36:10just woken up, I suppose,
0:36:10 > 0:36:12and on the night shift...
0:36:16 > 0:36:19..but that's not the special animal I'm after.
0:36:21 > 0:36:25In the depths of the Mitsinjo Forest Reserve,
0:36:25 > 0:36:27the populations of other elusive animals
0:36:27 > 0:36:29are being monitored and studied.
0:36:33 > 0:36:36The reserve has a research project,
0:36:36 > 0:36:38which means they put down pitfall traps,
0:36:38 > 0:36:41and trap animals that have been walking around
0:36:41 > 0:36:43on the forest floor in the dark.
0:36:45 > 0:36:48My quarry is both strange and strangely familiar.
0:36:49 > 0:36:52You might be reminded of something in your garden.
0:36:56 > 0:36:57Fantastic little animal.
0:36:59 > 0:37:00Beautiful.
0:37:10 > 0:37:12There we are.
0:37:12 > 0:37:16Well, it looks just like a hedgehog -
0:37:16 > 0:37:18and that's not a coincidence,
0:37:18 > 0:37:20because it lives just like a hedgehog.
0:37:20 > 0:37:23It eats worms and other invertebrates,
0:37:23 > 0:37:25mostly nocturnally...
0:37:25 > 0:37:26but it's no hedgehog.
0:37:26 > 0:37:29It belongs to a completely different group of animals.
0:37:29 > 0:37:32In fact, this is a tenrec.
0:37:32 > 0:37:35Its closest relative outside Madagascar
0:37:35 > 0:37:39is probably that extraordinary African animal, the aardvark.
0:37:39 > 0:37:43It's a fantastic example of convergent evolution.
0:37:43 > 0:37:46The tenrecs have turned into...
0:37:46 > 0:37:52oh, more than 20 species of endemic animals in Madagascar.
0:37:54 > 0:37:58As well as their protective spines and insect-based diets,
0:37:58 > 0:38:00like European hedgehogs,
0:38:00 > 0:38:03in the chillier winter months, this species of tenrec
0:38:03 > 0:38:07also drops into a form of semi-hibernation termed "torpor".
0:38:12 > 0:38:14As well as physically and behaviourally
0:38:14 > 0:38:16resembling other animals,
0:38:16 > 0:38:20some convergent species have also evolved
0:38:20 > 0:38:24almost inconceivably similar physiological traits.
0:38:26 > 0:38:31Madagascar's frogs have evolved defences almost identical
0:38:31 > 0:38:33to relatives that live thousands of miles away,
0:38:33 > 0:38:37that they can never have encountered, let alone interbred with.
0:38:39 > 0:38:42One example was rescued by Dr Devin Edmonds.
0:38:43 > 0:38:47So, these are brilliant orange frogs, and in amphibia,
0:38:47 > 0:38:50- usually, orange, bright colours are a warning sign.- Mm-hm.
0:38:50 > 0:38:52Is that the case here?
0:38:52 > 0:38:54This is exactly the case. Yeah.
0:38:54 > 0:38:57These bright colourations serve to warn predators
0:38:57 > 0:38:58that they're poisonous.
0:38:58 > 0:39:03So, what sort of toxin do these frogs have?
0:39:03 > 0:39:06They have several kinds of alkaloids in their skin
0:39:06 > 0:39:09that are distasteful and poisonous to predators,
0:39:09 > 0:39:11which they get from the prey that they eat -
0:39:11 > 0:39:13things like ants or beetles or mites.
0:39:13 > 0:39:17So they take the poison from the prey and plaster it on the outside.
0:39:17 > 0:39:18Exactly. Exactly.
0:39:18 > 0:39:21I've seen frogs brightly coloured like that in Central America.
0:39:21 > 0:39:24Yeah, this is kind of an interesting case of convergent evolution,
0:39:24 > 0:39:29where you have two frogs that are totally unrelated to each other,
0:39:29 > 0:39:32evolving in basically identical ways,
0:39:32 > 0:39:37so these frogs actually have the exact same alkaloids in their skin
0:39:37 > 0:39:40as their South American and Central American relatives.
0:39:40 > 0:39:42That really is quite extraordinary.
0:39:42 > 0:39:45This must have taken millions of years, for sure,
0:39:45 > 0:39:48- for this sort of sophistication to arise.- Mm-hm.
0:39:48 > 0:39:51It's quite extraordinary to think that this could happen twice
0:39:51 > 0:39:53in such a similar fashion.
0:40:00 > 0:40:05But the prize for the most unlikely example of how one animal has evolved
0:40:05 > 0:40:09to fill almost exactly the same ecological niche as another
0:40:09 > 0:40:14goes to a notoriously reclusive animal feared by Malagasy folklore.
0:40:18 > 0:40:20To all intents and purposes,
0:40:20 > 0:40:23it earns a living the same way as a woodpecker,
0:40:23 > 0:40:26and even builds a nest...
0:40:26 > 0:40:29but it's actually a type of lemur.
0:40:33 > 0:40:37If you look at the aye-aye, the aye-aye has big ears.
0:40:37 > 0:40:45To hear the larvae in the trees, they listen first to hear the noise,
0:40:45 > 0:40:49and then the teeth, very strong, incision to break...
0:40:49 > 0:40:51- To break wood.- ..the wood.
0:40:54 > 0:40:58Then they use the fingers to eat the larvae.
0:40:58 > 0:41:00So, sort of like a hook.
0:41:00 > 0:41:02Like a hook, to get the larvae.
0:41:06 > 0:41:09But, I mean, if this is so different from the other lemurs,
0:41:09 > 0:41:12it implies this has a long independent history.
0:41:12 > 0:41:16Exactly. So, once they come to the island,
0:41:16 > 0:41:18there's a huge radiation,
0:41:18 > 0:41:22and the aye-aye separate from the rest of the lemurs -
0:41:22 > 0:41:25they have their own evolution.
0:41:25 > 0:41:30In the past, people thought that the aye-aye was like a rodent,
0:41:30 > 0:41:34because of the teeth - but the aye-aye live like birds.
0:41:34 > 0:41:36They build nests.
0:41:41 > 0:41:45So, it's about as specialised a niche as you could possibly imagine.
0:41:45 > 0:41:47None of the lemurs has that features.
0:41:47 > 0:41:49Just the aye-aye.
0:41:51 > 0:41:54The aye-aye is such an extraordinary animal,
0:41:54 > 0:41:58you simply couldn't make it up from first principles.
0:41:59 > 0:42:03Today, this highly evolved loner is under threat
0:42:03 > 0:42:05from a gregarious generalist.
0:42:07 > 0:42:13Homo sapiens was the last primate colonist to reach Madagascar...
0:42:13 > 0:42:17but already this species has left an indelible mark.
0:42:19 > 0:42:23Surprisingly, the first human settlers to reach the island
0:42:23 > 0:42:27came not from Africa, 250 miles away,
0:42:27 > 0:42:31but from Borneo, more than 2,500 miles away.
0:42:32 > 0:42:36The reason was a change in ocean currents,
0:42:36 > 0:42:39which after millions of years of flowing west to east,
0:42:39 > 0:42:41changed to flow east to west,
0:42:41 > 0:42:46thus allowing early Bornean seafarers to drift gently with the currents
0:42:46 > 0:42:48to traverse the Indian Ocean.
0:42:53 > 0:42:56They settled in Madagascar's central highlands,
0:42:56 > 0:42:57where they cleared the forests
0:42:57 > 0:43:02and started creating terraced paddy fields to grow rice.
0:43:03 > 0:43:07And here is hidden tantalising evidence for early human encounters
0:43:07 > 0:43:11with some of the oddest creatures ever to live on Madagascar.
0:43:13 > 0:43:16The first fossil clue that led scientists to search
0:43:16 > 0:43:18for these now-vanished animals
0:43:18 > 0:43:21is to be found in the village of Sambaina.
0:43:24 > 0:43:28It's kept in a house owned by its discoverer, Mrs Medolin.
0:43:33 > 0:43:35Ah, hello!
0:43:36 > 0:43:38- Salama.- Salama!
0:43:38 > 0:43:41- Mrs Medolin.- Yes, salama.
0:43:41 > 0:43:45- Now, you have some bone here to show me.- Mm.
0:43:46 > 0:43:48- You found this.- Yeah.
0:43:48 > 0:43:50You found this.
0:43:50 > 0:43:54These are bones - giants' bones,
0:43:54 > 0:43:58found by Mrs Medolin in a nearby field.
0:43:58 > 0:44:01- Thank you very much for showing them to me.- Mm.
0:44:01 > 0:44:02We'll go and see if we can find them
0:44:02 > 0:44:05in the place where they occur, very near here.
0:44:10 > 0:44:14My fellow palaeontologist Karen Samonds and her team
0:44:14 > 0:44:18have been excavating a paddy field site for only two seasons...
0:44:21 > 0:44:24..but every day, new finds are rescued from the mud.
0:44:30 > 0:44:33Well, it's actually a funny story.
0:44:33 > 0:44:36We knew people found fossils from around this region,
0:44:36 > 0:44:39so we actually just found a spot to dig two simple pits,
0:44:39 > 0:44:43and in those two pits last year we found more than a hundred fossils.
0:44:43 > 0:44:44So, an instant bonanza.
0:44:44 > 0:44:47Yes. Instant bonanza - that's the way we like it, so...
0:44:47 > 0:44:51Just looking around, I can see it's a virtually horizontal plain
0:44:51 > 0:44:53surrounded on all sides by hills,
0:44:53 > 0:44:56- which makes any geologist think - a lake.- Yep.
0:44:56 > 0:44:58So, we have good evidence that this whole region
0:44:58 > 0:45:00was a giant fossil lake.
0:45:00 > 0:45:02The mountains that we see here are volcanic mountains.
0:45:02 > 0:45:05These mountains came up, and when they raised,
0:45:05 > 0:45:08it actually prevented some of the rivers from flowing west,
0:45:08 > 0:45:10and that region, the whole basin, then filled with water,
0:45:10 > 0:45:12forming the giant fossil lake.
0:45:13 > 0:45:15When it was a lake,
0:45:15 > 0:45:18it undoubtedly supported all sorts of different kinds of animals
0:45:18 > 0:45:19that relied on it, lived within it,
0:45:19 > 0:45:22and those are the animals that we find today.
0:45:25 > 0:45:27Ooh, so what have we got here?
0:45:27 > 0:45:29Ah, so this is part of an elephant bird -
0:45:29 > 0:45:31bone from the leg.
0:45:31 > 0:45:34So, you can imagine how massive this bird must have been.
0:45:34 > 0:45:35- It's huge.- It's a huge bird.
0:45:35 > 0:45:37Bigger than either of us.
0:45:37 > 0:45:39- And pretty strong.- Very strong, yep.
0:45:39 > 0:45:41And inside of the bone, you can see,
0:45:41 > 0:45:43it has a lot of these openings and holes,
0:45:43 > 0:45:45so even though it's a mammoth size,
0:45:45 > 0:45:47it still shows the signature of a bird,
0:45:47 > 0:45:49which is to try to lighten that - even that big bone.
0:45:49 > 0:45:53- And flightless. Needless to say. - Yes. A flightless bird.
0:45:53 > 0:45:55- And quite a lot of meat on it, I imagine.- Quite a lot -
0:45:55 > 0:45:57in fact, you can imagine those animals would have been
0:45:57 > 0:46:01- quite a prize for someone who wanted...- A big chicken dinner.
0:46:01 > 0:46:03..a big chicken dinner, yes!
0:46:05 > 0:46:07This is the jaw of a pygmy hippopotamus.
0:46:07 > 0:46:10So, you can see, here's one of the teeth.
0:46:10 > 0:46:12So, to us, I mean, this looks pretty big,
0:46:12 > 0:46:15but if you compare this to the size of an African hippo, say...
0:46:15 > 0:46:17- We are talking that sort of size. - Exactly.
0:46:17 > 0:46:18So, these guys went small.
0:46:18 > 0:46:20We have some things on islands getting small,
0:46:20 > 0:46:23and other things, like the elephant bird, getting really large.
0:46:23 > 0:46:24That's a common pattern on islands.
0:46:24 > 0:46:26Here's another hippo. Here we go.
0:46:26 > 0:46:28This one you can see more of the teeth.
0:46:28 > 0:46:31- Yeah, I can see... Those are the anterior.- Those are the anterior...
0:46:31 > 0:46:33- The front teeth. - ..front teeth, projecting forward.
0:46:33 > 0:46:34Here are some of the molars.
0:46:34 > 0:46:36And so, if we had to do a count,
0:46:36 > 0:46:39I'd say more than 80% of what we find is actually pygmy hippo,
0:46:39 > 0:46:40so there you go.
0:46:40 > 0:46:44And did this pygmy hippo overlap with the arrival of Homo sapiens?
0:46:44 > 0:46:47It certainly did, and, in fact, there's even some bones,
0:46:47 > 0:46:51cut marks on hippos, where you actually see butchery marks.
0:46:51 > 0:46:53People that must have hunted them and eaten them.
0:46:53 > 0:46:55So, that's almost the smoking gun.
0:46:55 > 0:46:56Yeah. Certainly.
0:46:56 > 0:46:58We know that they interacted,
0:46:58 > 0:47:01and humans must have prized them for hunting.
0:47:18 > 0:47:21Pulling bones out of mud is exciting,
0:47:21 > 0:47:25but what's really exciting is piecing those bones together
0:47:25 > 0:47:27to find a complete skeleton -
0:47:27 > 0:47:32and here we have the brontosaurus of the bird kingdom -
0:47:32 > 0:47:34the elephant bird.
0:47:34 > 0:47:36Aepyornis - and what a creature.
0:47:38 > 0:47:41Well, you can imagine its succulent thighs,
0:47:41 > 0:47:43its huge quantity of breast meat.
0:47:47 > 0:47:51As for the brain, well, it's got a very small brain case,
0:47:51 > 0:47:53so it was certainly no intellectual giant -
0:47:53 > 0:47:56but that hasn't stopped emus and ostriches
0:47:56 > 0:47:59doing very well for themselves, and still with us today.
0:47:59 > 0:48:01All a question of niche, as usual.
0:48:02 > 0:48:08But I suppose the real vulnerable spot for this animal was the egg.
0:48:10 > 0:48:13Probably the largest egg that ever existed.
0:48:13 > 0:48:1520 omelettes in a single shell.
0:48:18 > 0:48:21They once thronged in huge numbers all over Madagascar...
0:48:23 > 0:48:26..and it's so sad that they're no longer there today.
0:48:26 > 0:48:28I would love to have seen them.
0:48:39 > 0:48:43Well, we found a jawbone of this animal when we were in the field.
0:48:43 > 0:48:47It demonstrates another rule of island life -
0:48:47 > 0:48:50as well as things getting larger, some things get smaller.
0:48:50 > 0:48:53It's a pygmy hippopotamus.
0:48:53 > 0:48:56It's actually relatively easy to change size.
0:48:56 > 0:48:59It doesn't require a great deal of genetic reorganisation,
0:48:59 > 0:49:03so if food is short, or food changes,
0:49:03 > 0:49:06or the niche changes in some subtle way,
0:49:06 > 0:49:09then size change is relatively easily achieved.
0:49:20 > 0:49:24There were once even more species of lemur in Madagascar
0:49:24 > 0:49:26than there are today.
0:49:26 > 0:49:29There were ground-dwelling lemurs, megaladapis -
0:49:29 > 0:49:32example of island gigantism.
0:49:32 > 0:49:36Sadly, none of them survived the arrival of the human.
0:49:51 > 0:49:55Today, the bustling capital of Antananarivo
0:49:55 > 0:49:57is a melting pot of different peoples.
0:50:03 > 0:50:05The first settlers from Borneo
0:50:05 > 0:50:09were followed by waves of new colonists from Africa.
0:50:09 > 0:50:14People from India, the Arab world and China joined the melting pot.
0:50:18 > 0:50:21Finally, the arrival of Imperial Britain and France
0:50:21 > 0:50:25in the 19th century began a profound transformation.
0:50:28 > 0:50:32European plantation owners introduced eucalyptus trees to the island...
0:50:34 > 0:50:39..and the dire consequences of this are still being felt today.
0:50:39 > 0:50:41HE COUGHS
0:50:42 > 0:50:44This scene says it all, really.
0:50:44 > 0:50:48Behind me, a great swath of felled eucalyptus,
0:50:48 > 0:50:51and here it's been turned into charcoal,
0:50:51 > 0:50:53in this smouldering heap.
0:50:56 > 0:50:59The population of Madagascar is increasing at a tremendous rate,
0:50:59 > 0:51:02and you can understand why, in some ways,
0:51:02 > 0:51:06eucalyptus is regarded as a very useful crop -
0:51:06 > 0:51:10but, of course, it's also destroying the ecology.
0:51:15 > 0:51:18And here's the almost indestructible eucalyptus
0:51:18 > 0:51:21already regenerating from the charred stump.
0:51:29 > 0:51:33Around 80% of Madagascar's remaining forest
0:51:33 > 0:51:37is now being used to grow eucalyptus trees for charcoal fuel.
0:51:39 > 0:51:43If this rate of habitat loss continues unchecked,
0:51:43 > 0:51:44by some predictions,
0:51:44 > 0:51:5090% of the country's wild lemurs could be extinct in just 20 years.
0:51:52 > 0:51:56I can only hope the haunting calls of lemurs like the indri
0:51:56 > 0:52:00are not a foreboding of how fragile these creatures' future really is...
0:52:00 > 0:52:02LEMURS CALL
0:52:02 > 0:52:06..for "lemur", in Latin, means "ghost".
0:52:10 > 0:52:14Madagascar is the place where the ecological niche has triumphed.
0:52:14 > 0:52:17If there are a hundred different trades in nature,
0:52:17 > 0:52:21there are a hundred different species to fill them.
0:52:21 > 0:52:26The amphibia, the birds, the mammals, it's all the same -
0:52:26 > 0:52:31they have divided the environment into habitats that they can utilise.
0:52:31 > 0:52:35And how different this is from the eucalyptus monoculture.
0:52:35 > 0:52:38That's a kind of monopoly - a single trade -
0:52:38 > 0:52:40and very few of the animals and plants that live here
0:52:40 > 0:52:42can cope with it.
0:52:55 > 0:52:59I've come back to the pristine forest of the Mitsinjo Nature Reserve.
0:53:01 > 0:53:04Here, brothers Yousef and Mad,
0:53:04 > 0:53:07who run one of the country's reforestation programmes,
0:53:07 > 0:53:09are helping me to find some of the plants
0:53:09 > 0:53:13that they believe have valuable medicinal properties.
0:53:15 > 0:53:19The secrets they are uncovering make an unexpectedly strong case
0:53:19 > 0:53:21for preserving these unique habitats
0:53:21 > 0:53:24as the island's greatest resource.
0:53:33 > 0:53:34Mmm!
0:53:34 > 0:53:38Well, it's certainly quite pleasant-tasting.
0:53:38 > 0:53:41Makes you feel rather like a lemur.
0:53:41 > 0:53:42Hmm.
0:53:42 > 0:53:44These are sweet trees.
0:53:44 > 0:53:45- A sweet tree.- Yes.
0:53:45 > 0:53:51Now, most of the trees in this forest are not sweet trees.
0:53:51 > 0:53:56Most of them have unpleasant taste or are actually poisonous -
0:53:56 > 0:53:57but this one, not.
0:53:57 > 0:53:59This is not. This is sweet trees.
0:53:59 > 0:54:04If you get hungry in the forest, these trees can help you.
0:54:04 > 0:54:06So, if I was really hungry,
0:54:06 > 0:54:09I would eat one of these leaves and keep me going.
0:54:10 > 0:54:13This is part of the coffee family.
0:54:13 > 0:54:16Oh, right - a very big family in the tropics.
0:54:16 > 0:54:17Yes. Yeah.
0:54:17 > 0:54:18And what is it used for?
0:54:18 > 0:54:20This is good for the fever.
0:54:20 > 0:54:23- Oh, so it brings down high temperature.- Yes.
0:54:23 > 0:54:28Which, in an area where there is a lot of malaria, must be very useful.
0:54:28 > 0:54:29Yes. Oh, yeah.
0:54:29 > 0:54:32And you take the leaves and they cook the leaves
0:54:32 > 0:54:34and they drink the infusion.
0:54:34 > 0:54:36Does it taste unpleasant?
0:54:36 > 0:54:38Er, yeah, yeah - it's a little bit bitter.
0:54:38 > 0:54:39- Ah, right.- Yeah.
0:54:39 > 0:54:41THEY CHUCKLE
0:54:43 > 0:54:45Ah!
0:54:45 > 0:54:48A plant with conspicuous white berries.
0:54:50 > 0:54:51What is this one?
0:54:51 > 0:54:54This is Malagasy tea.
0:54:54 > 0:54:56This plant is help us for the...
0:54:56 > 0:54:59blood...high blood pressure.
0:54:59 > 0:55:01- Ah, right - it reduces blood pressure.- Yes.
0:55:01 > 0:55:05This is a native for Madagascar.
0:55:05 > 0:55:06I mean, that's the thing -
0:55:06 > 0:55:11these forests are full of secret ingredients, really,
0:55:11 > 0:55:14- for human use, eventually.- Mm-hm.
0:55:18 > 0:55:22A few of the 600 or more endemic trees and plants
0:55:22 > 0:55:25have already been used to create new medicines -
0:55:25 > 0:55:27including anti-cancer drugs.
0:55:29 > 0:55:32I'm told that the Malagasy name of this plant
0:55:32 > 0:55:34means "take away all your worries",
0:55:34 > 0:55:37so I'm looking forward to an infusion of that one.
0:55:41 > 0:55:43Yousef and Mad have promised me
0:55:43 > 0:55:46it is safe to try out some of the leaves we found
0:55:46 > 0:55:47with my Malagasy meal.
0:55:49 > 0:55:52So, this is my Malagasy gastronomy.
0:55:52 > 0:55:53The empty plate -
0:55:53 > 0:55:59well, there is no animal source of endemic protein here.
0:55:59 > 0:56:03Enough tenrecs and lemurs have been eaten already.
0:56:03 > 0:56:11But I am allowed to eat banana bread wrapped in endemic ginger species.
0:56:11 > 0:56:14And I may need it to take the taste away.
0:56:14 > 0:56:18There's several species of ginger in Madagascar,
0:56:18 > 0:56:21but this one is an endemic species,
0:56:21 > 0:56:24and it should give the bread a special flavour.
0:56:25 > 0:56:28And it's rather nice.
0:56:28 > 0:56:32Now, I'm going to start with Malagasy tea.
0:56:32 > 0:56:35Supposedly good for blood pressure, as well.
0:56:39 > 0:56:42And it's really quite pleasant...
0:56:42 > 0:56:43and quite refreshing.
0:56:46 > 0:56:48I've been slightly dreading the next one.
0:56:48 > 0:56:51This is the one that's apparently good for fever.
0:56:55 > 0:56:56Ugh.
0:56:56 > 0:56:57And nor does it.
0:56:57 > 0:56:59It's kind of very bitter,
0:56:59 > 0:57:01but it's got that sort of it's-good-for-you taste,
0:57:01 > 0:57:02if you know what I mean. I'll just...
0:57:05 > 0:57:09Now, fortunately, I have a brew made from the tree
0:57:09 > 0:57:11that cures all known ills.
0:57:15 > 0:57:16Ahh!
0:57:18 > 0:57:20Well, I can feel the bliss coming on.
0:57:34 > 0:57:38It took tens of millions of years living in rainforests like these
0:57:38 > 0:57:41for such magical varieties of plants and animals to evolve.
0:57:45 > 0:57:50Nestled in the branches or creeping through the leaf litter,
0:57:50 > 0:57:54teem hundreds upon hundreds of species -
0:57:54 > 0:57:56many still unknown to science.
0:57:58 > 0:58:03Their fragile lives prove how an island such as Madagascar
0:58:03 > 0:58:06is both a laboratory for evolution
0:58:06 > 0:58:10and a haven for the sort of adaptive experimentation
0:58:10 > 0:58:13that can take place nowhere else.
0:58:20 > 0:58:23In the next episode, we travel to the island of Madeira -
0:58:23 > 0:58:27an ark of ancient forests and rich marine habitats...
0:58:29 > 0:58:33..but an island that is approaching the end of its life cycle,
0:58:33 > 0:58:36to return to the sea from which it arose.