0:00:08 > 0:00:14On the far side of the world is an island carved by waterfalls
0:00:14 > 0:00:17and forged by volcanoes.
0:00:17 > 0:00:20Look at that! It's being thrown a kilometre into the air.
0:00:23 > 0:00:26New Guinea, home to ancient cultures,
0:00:26 > 0:00:30the last great frontier of jungle exploration in the world.
0:00:33 > 0:00:38For a nine-month period, a team of scientists, film-makers and cavers
0:00:38 > 0:00:41have been exploring the most remote parts of this island.
0:00:41 > 0:00:44The terrain looks a total nightmare!
0:00:44 > 0:00:47This is what we do expeditions for, places like this.
0:00:47 > 0:00:52Unimaginably beautiful and totally unexplored.
0:00:54 > 0:00:57They've witnessed the birth of new mountains
0:00:57 > 0:01:00and explored ancient craters.
0:01:00 > 0:01:03To find something that's never before been seen by science,
0:01:03 > 0:01:07this has got to be one of the most incredible moments of my life.
0:01:07 > 0:01:09That is just fantastic.
0:01:09 > 0:01:12They've discovered animals found nowhere else.
0:01:13 > 0:01:15Wow, wow, wow! Jeepers.
0:01:15 > 0:01:18Look at that.
0:01:18 > 0:01:20Their aim?
0:01:20 > 0:01:25To search for species new to science and find the evidence to help preserve these forests for ever.
0:01:25 > 0:01:30We can't save everything, but we have to save the richest places,
0:01:30 > 0:01:33and the richest places on Earth are forests like this.
0:02:00 > 0:02:02New Guinea.
0:02:02 > 0:02:06A huge tropical island on the edge of the South Pacific Ocean.
0:02:09 > 0:02:15This rugged jungle hides a network of deep, isolated valleys.
0:02:15 > 0:02:19They're the most promising places in the world to find rare animals.
0:02:20 > 0:02:24The creatures that have evolved here are truly strange.
0:02:24 > 0:02:28Kangaroos that live in trees,
0:02:28 > 0:02:30exotic birds of paradise...
0:02:33 > 0:02:37..giant cassowaries with their armoured crests,
0:02:37 > 0:02:40and the shy and secretive cuscus.
0:02:43 > 0:02:50At the heart of the island is Mount Bosavi, a giant volcano long since
0:02:50 > 0:02:53extinct, and the team's home for this phase of the expedition.
0:03:05 > 0:03:10On their way in is a team of experts on the animals of New Guinea.
0:03:10 > 0:03:15But for wildlife cameraman Gordon Buchanan, it's his first time here.
0:03:15 > 0:03:18This is a very, very difficult terrain.
0:03:18 > 0:03:24You've got these steep gullies, riverine valleys and very, very thick forest.
0:03:24 > 0:03:29Very much the unknown and somewhere that I'm really quite nervous about.
0:03:32 > 0:03:36They're heading for a base camp in the foothills of Mount Bosavi.
0:03:36 > 0:03:39George McGavin is head of the science team.
0:03:39 > 0:03:44He's already in camp, with some of the tribe who own this ancient land.
0:03:44 > 0:03:49They'll be working with the scientists and filmmakers to find the forest creatures.
0:03:49 > 0:03:52The heart of this camp is the jungle lab.
0:03:52 > 0:03:56We have assembled a team of specialists, world experts
0:03:56 > 0:04:01in their groups - birds, reptiles, amphibians, bats, insects - and they're going to be working in here.
0:04:22 > 0:04:28That helicopter kicks up quite a blast, but that's all the scientists coming in.
0:04:30 > 0:04:33Hi, there's lots of work for you here!
0:04:33 > 0:04:37Each expert has their own special skill for finding rare animals.
0:04:44 > 0:04:50They'll be exploring for new species in a forgotten corner of our planet.
0:04:50 > 0:04:56It's a task more vital today than ever, as this ancient forest has an uncertain future.
0:05:03 > 0:05:06Steve Backshall is the last member to arrive.
0:05:06 > 0:05:11How we're going to move around in here and go about actually trying to find wildlife,
0:05:11 > 0:05:13I have no idea.
0:05:16 > 0:05:20It's the third time that Gordon, George and Steve have been on jungle expeditions together.
0:05:23 > 0:05:27George is the scientist. He'll go anywhere in his search for strange insects.
0:05:27 > 0:05:30Gordon is the wildlife cameraman.
0:05:30 > 0:05:34Nothing will stop him getting the perfect picture.
0:05:34 > 0:05:37Steve is the adventurer and climber.
0:05:37 > 0:05:40Whether it's up mountains or down waterfalls,
0:05:40 > 0:05:43the bigger the challenge, the better it is.
0:05:45 > 0:05:47Day one in the New Guinea base camp.
0:05:47 > 0:05:51As they prepare the gear, something bizarre arrives in camp.
0:05:51 > 0:05:53George, you come here. I've got one thing for you.
0:05:53 > 0:05:56It's been caught by boatman Nick Awaiyo
0:05:56 > 0:05:59and expedition photographer Ulla Lohmann.
0:06:01 > 0:06:03There's no rest in this place.
0:06:03 > 0:06:07Oh, my God, that is absolutely incredible.
0:06:09 > 0:06:14A thing that folks don't often think is that stick insects can fly.
0:06:14 > 0:06:17I can just take it off the camera lens.
0:06:17 > 0:06:20The front wings are quite short,
0:06:20 > 0:06:24little tiny...little winglets there,
0:06:24 > 0:06:28but the hind wings are just beautifully fan-like,
0:06:28 > 0:06:30like a big pleat.
0:06:30 > 0:06:35That is the biggest stick insect I have ever seen in the wild.
0:06:38 > 0:06:43Working with a team of skilled boatmen, Steve is keen to head downstream.
0:06:46 > 0:06:51He'll be exploring the fast-flowing rivers that pour down these mountains.
0:06:58 > 0:07:01It really is spectacular, if a little bit up and down.
0:07:01 > 0:07:05There's an awful lot of water flowing through here.
0:07:05 > 0:07:10It's a fantastic opportunity for us to get somewhere that is just almost totally unknown.
0:07:18 > 0:07:24These rivers are the roads of the rainforest, eventually taking Steve into uncharted territory.
0:07:24 > 0:07:28In New Guinea, the rivers roar not just over the ground,
0:07:28 > 0:07:33but also underground, through caves deep within these limestone mountains.
0:07:33 > 0:07:40Steve's journey will ultimately lead him to follow a river deep into this underworld.
0:07:40 > 0:07:43He'll be exploring where no human has ever been,
0:07:43 > 0:07:46living and sleeping under a million tonnes of rock.
0:07:49 > 0:07:54Back in base camp, Gordon's preparing to trek into the forest.
0:07:54 > 0:08:01He'll be working with a team of trackers to capture on camera the secretive animals of this jungle.
0:08:01 > 0:08:05There's no point of reference in Papua New Guinea.
0:08:05 > 0:08:09There are no cats, there are no rhinos, there are no elephants, there are no monkeys.
0:08:09 > 0:08:12There is nothing familiar about the creatures that live in this forest.
0:08:12 > 0:08:15So in some ways, I feel as if I'm starting from scratch.
0:08:15 > 0:08:20It's quite daunting, the prospect of going into this forest and starting to look for things.
0:08:23 > 0:08:28But New Guinea does have the most spectacular and strange birds in the world.
0:08:28 > 0:08:32From now on, Gordon will be out searching for them.
0:08:38 > 0:08:40Hornbills.
0:08:40 > 0:08:43You never, ever see them from the ground.
0:08:43 > 0:08:47One of the largest birds of New Guinea, the hornbill.
0:08:49 > 0:08:52But he soon finds signs of a real giant of a bird.
0:08:54 > 0:08:57Ooh! There's something there, hang on.
0:08:57 > 0:09:01This is the first thing that I've found. It's a cassowary footprint.
0:09:01 > 0:09:02And this is an enormous bird.
0:09:02 > 0:09:06That footprint is the size of my hand,
0:09:06 > 0:09:09so we're talking about a bird that's about kind of four, five feet tall.
0:09:09 > 0:09:12I'd love to be able to find one of them.
0:09:15 > 0:09:22In the jungle lab, the experts sort their equipment, before starting their hunt for animals.
0:09:22 > 0:09:27The team has come from all over the world and is working with some of New Guinea's leading scientists.
0:09:30 > 0:09:36They're led by Dr George McGavin, a specialist in insects from Oxford University.
0:09:38 > 0:09:40He's set an ambitious target.
0:09:40 > 0:09:44This whole area is completely unexplored and as head of the scientist team,
0:09:44 > 0:09:48I want to find at least 30 new species right here.
0:09:50 > 0:09:55This goal isn't just for the sake of science.
0:09:55 > 0:09:59Proving this forest is rich can be a powerful reason to protect it.
0:10:00 > 0:10:04Just 20 miles south, the jungle is disappearing.
0:10:11 > 0:10:15If we're to have any chance of saving it,
0:10:15 > 0:10:20we have to be able to tell everybody this is a very rich area.
0:10:20 > 0:10:25Hopefully, we'll find some new species to keep people aware of
0:10:25 > 0:10:29the fact that these habitats still exist and are worth saving.
0:10:29 > 0:10:37If the forests go, we will lose the majority of species on Earth without even knowing they were there.
0:10:42 > 0:10:45Steve and the river team are five miles downstream.
0:10:50 > 0:10:54Around them, waterfalls pour down from Mount Bosavi.
0:10:54 > 0:10:56Oh, wow, this is a monster!
0:11:01 > 0:11:03These tracks here...
0:11:04 > 0:11:06..are croc tracks.
0:11:06 > 0:11:11This is quite clearly the hind foot of a croc.
0:11:11 > 0:11:14It's been coming in from this direction.
0:11:14 > 0:11:17It's come up to check something out.
0:11:17 > 0:11:20The tracks lead back into the forest.
0:11:23 > 0:11:25Crocodile nest!
0:11:25 > 0:11:28But it's been... You can see it's been dug up.
0:11:28 > 0:11:33This one's still got amniotic fluid inside it, look.
0:11:33 > 0:11:37This has happened very recently, possibly last night.
0:11:37 > 0:11:42Well, this isn't the hatchlings breaking out of their own accord.
0:11:42 > 0:11:48They have an egg tooth, which is on the end of their nose, which they use to break out of the egg
0:11:48 > 0:11:52and they make a very clean departure, whereas this has just been shredded.
0:11:52 > 0:11:58And I am 99% sure these have been taken by a monitor lizard.
0:11:58 > 0:12:02That's one of the biggest predators of nests like this.
0:12:06 > 0:12:11What a shame. This forest does feel prehistoric to me.
0:12:11 > 0:12:14It feels like a place where you could see a dinosaur around every corner.
0:12:14 > 0:12:18And crocodiles have been around since the time of the dinosaurs and this is
0:12:18 > 0:12:23exactly the way that a Velociraptor, or a T Rex, would have laid its eggs, buried in the vegetation.
0:12:30 > 0:12:34There's an art to finding the creatures that hide in these forests.
0:12:34 > 0:12:38Scientists put up survey nets to find birds and bats,
0:12:38 > 0:12:41fishing nets are placed in the creeks...
0:12:43 > 0:12:47..and George walks quietly, searching for insects.
0:12:55 > 0:12:59Deep in the forest, Gordon's found a tiny nest.
0:12:59 > 0:13:04It looks like it belongs to a curiosity of nature,
0:13:04 > 0:13:07one of the smallest parrots in the world.
0:13:07 > 0:13:10Oh, wow - here, right here.
0:13:10 > 0:13:15As you can imagine, a pygmy parrot is pretty small, that's how it got its name.
0:13:15 > 0:13:19They're tiny, they're only about...not much bigger than my thumb.
0:13:19 > 0:13:26It's actually quite a big hole for a small bird and what they do on these rock-solid termite mounds,
0:13:26 > 0:13:30they'll dig in - probably using their beaks and their claws -
0:13:30 > 0:13:33and burrow down into it and lay their eggs there.
0:13:33 > 0:13:38But this is all quite, all fresh stuff, it's just been excavating this morning.
0:13:38 > 0:13:42I'm kind of concerned that it might not come back,
0:13:42 > 0:13:45but it's definitely worth setting up the hide and just waiting it out.
0:13:52 > 0:13:57To have any chance of filming these tiny birds, he must blend into the background
0:13:57 > 0:14:01and settle down for a long wait.
0:14:05 > 0:14:09George is taking a more active approach to finding his insects.
0:14:10 > 0:14:16Wood like this is an incredibly useful food material for loads of insects.
0:14:16 > 0:14:19I mean, it's eaten by beetles and termites and lots of stuff.
0:14:19 > 0:14:23There isn't anything wasted in the jungle, it's all recycled.
0:14:25 > 0:14:30There's over one million species of insects known to be living in jungles,
0:14:30 > 0:14:35and scientists estimate there's another five million waiting to be discovered,
0:14:35 > 0:14:37if you know where to look.
0:14:38 > 0:14:43Ooh, there's a nice beetle! I've got to work very carefully now, cos...
0:14:43 > 0:14:48I don't want to hurt them. There we are, look at that.
0:14:48 > 0:14:52There she is. A bess beetle.
0:14:52 > 0:14:54They are fantastic.
0:14:54 > 0:14:56That's a reward and a half.
0:14:56 > 0:15:00She's got fantastic little red hairs all round the thorax here.
0:15:00 > 0:15:02What a find.
0:15:02 > 0:15:07His first discovery is from a group of obscure and odd animals - talking beetles.
0:15:07 > 0:15:12They live in groups with their young ones and they call to each other as well.
0:15:12 > 0:15:14They make squeaks.
0:15:14 > 0:15:19If you can get the boom down, I'll just try to make it squeak.
0:15:20 > 0:15:23BEETLE CHIRRUPS
0:15:23 > 0:15:26I can hear it from here.
0:15:26 > 0:15:30In the dark, in logs, you can't see each other, but if you can make squeaking noises,
0:15:30 > 0:15:32then you know where each other are.
0:15:34 > 0:15:36An extraordinary find.
0:15:36 > 0:15:39New Guinea is THE place for the weird and wonderful.
0:15:41 > 0:15:48These forests are the most diverse and complex habitats that have ever evolved on Earth.
0:15:48 > 0:15:53There's a huge store of species here about which we know nothing at all.
0:15:53 > 0:16:00If you lose these forests, from being a very rich planet, we would instantly become a very poor one.
0:16:00 > 0:16:05So that is absolutely...gorgeous, absolutely gorgeous.
0:16:08 > 0:16:12Steve's on the river survey with fish expert Phil Willink.
0:16:12 > 0:16:15They're trying to get to a jungle creek to check the nets.
0:16:20 > 0:16:22In just the wrong place, the engine fails.
0:16:22 > 0:16:26- You OK?- Yeah.
0:16:26 > 0:16:28Don't think we want to go in that.
0:16:28 > 0:16:30They're caught in a whirlpool.
0:16:30 > 0:16:34Why is this...not...starting?
0:16:39 > 0:16:41Whoa!
0:16:45 > 0:16:47- It's chucked us out.- Hang on.
0:16:47 > 0:16:52The whirlpool throws them free, but then they're trapped in a vicious current and the engine's dead.
0:16:52 > 0:16:56Here, you want to paddle? Switch it off.
0:16:56 > 0:16:59I'm not sure we're gonna make it.
0:17:01 > 0:17:04Gordon's still patiently watching the nest of the pygmy parrot.
0:17:08 > 0:17:11There's simply no way round this.
0:17:11 > 0:17:14If you want to film animals in the wild, most of the time,
0:17:14 > 0:17:17you've got to do a stakeout.
0:17:17 > 0:17:20Sit tucked away in a hide and just sit and wait.
0:17:21 > 0:17:24You can't really switch off in a hide,
0:17:24 > 0:17:28you can't read a book or pick your toenails, you've got to stay alert
0:17:28 > 0:17:34and try and tune in to the sounds and the changes in the sounds
0:17:34 > 0:17:37and anticipate the arrival of the animal that you're after.
0:17:39 > 0:17:43After a struggle with the current, Steve and Phil make it to the bank.
0:17:45 > 0:17:48Well, that's our first warning of what this river can do.
0:17:48 > 0:17:50This river's a beast.
0:17:50 > 0:17:52It just creates incredible currents.
0:17:52 > 0:17:55And you saw the boat there just being span round in a whirlpool.
0:17:55 > 0:17:58It's very difficult to do anything about it really.
0:18:00 > 0:18:02MOTOR STARTS
0:18:02 > 0:18:07With the boat bailed out and the engine sorted, they're off again.
0:18:07 > 0:18:10That's the creek mouth straight ahead.
0:18:13 > 0:18:16There's a rock right here, go left.
0:18:16 > 0:18:19Whoa, cut the engine.
0:18:20 > 0:18:21SPLASHING
0:18:21 > 0:18:24Ooh, I heard something splosh up ahead.
0:18:24 > 0:18:26Ooh! That's a venomous catfish.
0:18:26 > 0:18:30- No way!- Yeah. Let's be a little careful here.
0:18:30 > 0:18:34- It's probably best to grab it from the head.- If I get whacked, how bad a day will I have?
0:18:34 > 0:18:37It's basically the same as getting hit by a stingray spine.
0:18:37 > 0:18:41What an extraordinary looking fish! That is a true alien mouth, isn't it?
0:18:41 > 0:18:46- Look at that.- They're covered with taste buds, it's actually tasting its environment all the time.
0:18:46 > 0:18:50Its eyes are not particularly large, so it has to use other senses
0:18:50 > 0:18:52to find things, particularly in these muddy rivers here.
0:18:52 > 0:18:58Look at the dorsal spine coming erect there, and at the end of it, you can see the sharp tip to it.
0:18:58 > 0:19:03And, you know, it's living in the same river with giant crocodiles, so it needs a defence.
0:19:03 > 0:19:06These spines also can go up and then lock into place,
0:19:06 > 0:19:08so if a crocodile tried to grab it,
0:19:08 > 0:19:10it would go through the roof of its mouth.
0:19:10 > 0:19:14It's amazing to think that a fish like this can actually defend itself
0:19:14 > 0:19:17against a three, four-metre long crocodile.
0:19:17 > 0:19:20If it's going to hurt one of those, it's sure as heck going to hurt one of us.
0:19:20 > 0:19:23Oh, yeah, so you've got to be really careful.
0:19:25 > 0:19:28Gordon is still crouched in his hide,
0:19:28 > 0:19:31and he's found absolutely nothing.
0:19:38 > 0:19:41The heat I can contend with,
0:19:41 > 0:19:45but the heat combined with the kind of infestation
0:19:45 > 0:19:48of bees and mosquitoes,
0:19:48 > 0:19:52that's when it gets very unpleasant.
0:19:55 > 0:19:58George is finding it a lot easier to uncover his creatures.
0:20:01 > 0:20:03This place is full of surprises.
0:20:03 > 0:20:06Millipedes are normally quite tough animals,
0:20:06 > 0:20:10but this one is incredibly tough. Very, very armoured.
0:20:10 > 0:20:13It has these little spines that point backwards
0:20:13 > 0:20:14all the way along it,
0:20:14 > 0:20:18which must help it as it drives under logs and soil and stuff,
0:20:18 > 0:20:20cos that's where it lives.
0:20:20 > 0:20:22It's absolutely weird.
0:20:22 > 0:20:24Very strange-looking animal.
0:20:27 > 0:20:30And there's an even more bizarre find.
0:20:30 > 0:20:37These ants have been infected by the spores of some fungal disease.
0:20:37 > 0:20:41And the fungus infects them in such a bizarre way that it causes them
0:20:41 > 0:20:45to crawl upwards, and it glues them onto a leaf.
0:20:45 > 0:20:50As the fungus eventually breaks out through the shell at the end,
0:20:50 > 0:20:52it grows this little stalk here,
0:20:52 > 0:20:55and there's some little balls there which contain spores.
0:20:55 > 0:21:00From those balls will erupt the spores, which will blow as far
0:21:00 > 0:21:05as they can and infect a whole new group of ants.
0:21:05 > 0:21:09So it's a really smart trick. And underneath every leaf here
0:21:09 > 0:21:13are those ants just pinned onto the leaf,
0:21:13 > 0:21:19dead husks, sucked dry by the fungal disease which has infected them.
0:21:19 > 0:21:22Absolutely amazing.
0:21:24 > 0:21:28At last, Gordon gets his reward.
0:21:28 > 0:21:30The pygmy parrots have returned to their nest.
0:21:30 > 0:21:32Look, there they are.
0:21:32 > 0:21:35They're on the nest.
0:21:35 > 0:21:37Oh, my word,
0:21:37 > 0:21:41they are tiny.
0:21:41 > 0:21:45Oh, wow! That is the weirdest thing.
0:21:47 > 0:21:51We've got a parrot here that is significantly smaller
0:21:51 > 0:21:55than many of the insects that live in this forest.
0:21:56 > 0:21:58And they're very much a parrot.
0:21:58 > 0:22:01His feet are true parrot feet,
0:22:01 > 0:22:05two toes facing forward, two facing back.
0:22:05 > 0:22:09They seem very affectionate with each other,
0:22:09 > 0:22:12which is quite typical of parrots.
0:22:12 > 0:22:16Parrots have a strong bond between male and female,
0:22:16 > 0:22:21sidling up to each other, beak-rubbing
0:22:21 > 0:22:25and constantly reinforcing their relationship.
0:22:25 > 0:22:28They move so fast, it's very jerky,
0:22:28 > 0:22:30it looks as if it's almost speeded up.
0:22:34 > 0:22:37You shouldn't say that animals are adorable in the wild,
0:22:37 > 0:22:40but they are simply adorable.
0:22:45 > 0:22:47Stop.
0:22:47 > 0:22:50Pretty pleased with that.
0:22:50 > 0:22:53Back at camp, it's been a good day for the scientists.
0:22:53 > 0:22:57Already, it seems this forest is incredibly rich.
0:23:00 > 0:23:04Jack Dumbacher is searching for the birds of the jungle,
0:23:04 > 0:23:07and investigating the diseases they carry.
0:23:07 > 0:23:12One of the things that's very interesting to me here is that we have a very pristine environment,
0:23:12 > 0:23:15and birds and other wildlife carry natural diseases,
0:23:15 > 0:23:20and so understanding these diseases, how they're spread, how they're moved around by birds and humans,
0:23:20 > 0:23:24is very, very important, for conservation as well as for basic biology.
0:23:27 > 0:23:30The birds are recorded by the expedition photographer.
0:23:36 > 0:23:39And then they can fly home.
0:23:44 > 0:23:47Alan Allison is passionate about frogs.
0:23:47 > 0:23:50He's been studying them in New Guinea for over 30 years,
0:23:50 > 0:23:53but he's never seen this one before.
0:23:53 > 0:23:56Interestingly enough, they call when it first gets dark -
0:23:56 > 0:24:00just about seven o'clock - and they call for about an hour.
0:24:00 > 0:24:01Seven o'clock frog.
0:24:01 > 0:24:03You can tell the time by it.
0:24:03 > 0:24:06It's a different species here than elsewhere.
0:24:06 > 0:24:09- That's added one new species to our vertebrate list.- That's right.
0:24:09 > 0:24:14To be finding new species already bodes very well for the expedition.
0:24:16 > 0:24:21For the moment, the scientists are hidden in the foothills of Mount Bosavi.
0:24:23 > 0:24:27But in a few weeks, the team will head higher
0:24:27 > 0:24:29up the steep mountain slopes
0:24:29 > 0:24:31and down into the heart of this extinct volcano.
0:24:34 > 0:24:40This giant crater is trapped from the outside world by walls half a mile high.
0:24:42 > 0:24:46They will be the first scientists ever to travel into this lost world.
0:24:46 > 0:24:50They believe it could hide truly spectacular new creatures.
0:24:54 > 0:25:00Mount Bosavi is a huge mountain - large enough to generate its own weather system.
0:25:00 > 0:25:02And mostly, that means rain.
0:25:04 > 0:25:07I do love it when it's like this, when the rain really comes down.
0:25:07 > 0:25:10That's the real force and power of this place.
0:25:10 > 0:25:12It's what makes everything work.
0:25:12 > 0:25:13If there wasn't this amount of rain,
0:25:13 > 0:25:15you wouldn't have this amount of life.
0:25:18 > 0:25:22Ugh! Very refreshing.
0:25:22 > 0:25:27Jack has been collecting birds away from the rest of the team,
0:25:27 > 0:25:29and has a surprise for Gordon.
0:25:29 > 0:25:34- What have you got, Jack? - You'll never believe it.
0:25:34 > 0:25:38- Oh, wow!- This is your little buff-faced pygmy parrot.
0:25:38 > 0:25:39Oh, goodness me!
0:25:39 > 0:25:45So if you can just hold your fingers as close as you can to his body...
0:25:45 > 0:25:49- Let me grab his legs again... - Ow! That's a parrot's beak.
0:25:49 > 0:25:51Yeah, it's pointy...
0:25:51 > 0:25:53He can't do that much damage.
0:25:53 > 0:25:55Oh, man!
0:25:55 > 0:25:57That is just the cutest thing.
0:25:57 > 0:26:01So now you can really see how tiny he is, like, compared to your thumb.
0:26:01 > 0:26:03- Yeah. He is just a parrot in miniature.- Yup.
0:26:03 > 0:26:09You cannot believe that a parrot can be this small.
0:26:11 > 0:26:14This tiny bird weighs less than half an ounce.
0:26:14 > 0:26:16Oh, my word.
0:26:18 > 0:26:21In the forest, actually, the feather... Ow!
0:26:23 > 0:26:24Oh!
0:26:28 > 0:26:32And actually, one of the things I wanted to do was get a little bit of DNA.
0:26:32 > 0:26:35I wasn't gonna take blood from him, cos he's a little bit too small.
0:26:35 > 0:26:39So we did get one feather he left us, so we can use that.
0:26:43 > 0:26:46That evening, the pygmy parrot is the butt of all the jokes.
0:26:46 > 0:26:52You can guarantee that somewhere in these forests, there'll be a tiny little pirate.
0:26:55 > 0:26:57Just the way that nature works.
0:26:58 > 0:27:02- "Who's a tiny boy, then?" - "Pieces of two!"
0:27:02 > 0:27:05THEY LAUGH
0:27:10 > 0:27:15- There's a fully grown larva there. - The jungle lab is filling with new and curious creatures.
0:27:18 > 0:27:23I'll bet you any money, that wasp right there, that's walking along that leaf, is a new species.
0:27:23 > 0:27:26I'll bet you any money.
0:27:32 > 0:27:3442mm long.
0:27:34 > 0:27:39Alanna Maltby is a bat expert from the Zoological Society of London.
0:27:39 > 0:27:40Oh, he's tiny!
0:27:40 > 0:27:43Yeah, he's really small and really cute.
0:27:43 > 0:27:46- What is it?- It's a bent-winged bat. And I'll show you why.
0:27:46 > 0:27:48Most bats, they just have their fingers,
0:27:48 > 0:27:51and when they fold their wings, they just fold them straight up.
0:27:51 > 0:27:54But this one folds them doubly...
0:27:54 > 0:27:56- Oh, right! - ..because they're really long.
0:27:56 > 0:27:59But I can't figure out which bent-winged bat it is.
0:27:59 > 0:28:02It doesn't quite match with any of the descriptions.
0:28:02 > 0:28:05- Which means?- Which means it could be a new species.
0:28:05 > 0:28:09A new species of furry animal. A mammal! Absolutely brilliant!
0:28:09 > 0:28:13- Which is quite rare, to find a new species of mammal.- Yeah, it is, very rare.
0:28:15 > 0:28:18A small creature, but a big discovery.
0:28:18 > 0:28:22No-one expected this success so soon.
0:28:29 > 0:28:32Rainforests come alive at night.
0:28:32 > 0:28:36Gordon treks out to find what's hiding there.
0:28:38 > 0:28:42Rainforests are very difficult places to work at the best of times.
0:28:42 > 0:28:47But this forest in particular is extra tough, because the animals
0:28:47 > 0:28:51that live here are very secretive and they're incredibly well hidden.
0:28:54 > 0:28:57He has an infrared camera for filming in the dark.
0:28:57 > 0:29:00There's something moving in the undergrowth.
0:29:03 > 0:29:05Wow!
0:29:08 > 0:29:11It's pretty big. It's about a metre and a half, maybe.
0:29:11 > 0:29:14And really, I daren't go any closer than I am to it.
0:29:17 > 0:29:19I think it's a small-eyed snake.
0:29:19 > 0:29:24These things lurk about in the leaf litter, and they...they kill people.
0:29:26 > 0:29:28Very, very, very dangerous snake.
0:29:28 > 0:29:33It would be very bad news if you were to stand on one of these.
0:29:33 > 0:29:34Oh...
0:29:38 > 0:29:39He's just opened his mouth right up.
0:29:39 > 0:29:42That's a sinister-looking snake.
0:29:42 > 0:29:45It really does freak me out,
0:29:45 > 0:29:51seeing something as dangerous as this in the forest at night time.
0:29:51 > 0:29:54It'd be so easy to stand on a snake like this.
0:29:54 > 0:29:56They need a positive identification.
0:29:56 > 0:29:59Steve is the team's snake specialist.
0:30:01 > 0:30:04He thinks it might be one of the most venomous snakes round here.
0:30:08 > 0:30:10Hello, guys.
0:30:10 > 0:30:12Oh, wow!
0:30:12 > 0:30:14Look at that! Gordy...
0:30:14 > 0:30:17- Is that a small-eyed snake? - It looks almost definitely like one.
0:30:17 > 0:30:23The only way you can really tell is to get up close and look at the amount of scales around the eye.
0:30:28 > 0:30:30The snake's obviously hunting.
0:30:30 > 0:30:32Ooh!
0:30:39 > 0:30:41Striking quite vigorously.
0:30:41 > 0:30:43Ooh!
0:30:45 > 0:30:47Where's the head?
0:30:47 > 0:30:51Need to pin the head to get control of the snake.
0:30:54 > 0:30:58So, now that I've got it up close, you can see although it does have
0:30:58 > 0:31:02that tiny, beady, black, recessed eye that you'd expect
0:31:02 > 0:31:09from the small-eyed snake, it also has a couple of extra scales between the eye and the nostril.
0:31:09 > 0:31:10It's a ground snake,
0:31:10 > 0:31:14not venomous, but very aggressive and always ready to strike.
0:31:14 > 0:31:18So, Gordy. Fantastic, mate!
0:31:18 > 0:31:21So it's not a small-eyed snake?
0:31:21 > 0:31:23It's not a small-eyed snake.
0:31:23 > 0:31:26- And it'll eat rodents, frogs, lizards, sort of...?- Yeah.
0:31:26 > 0:31:29All the things you're trying to film.
0:31:33 > 0:31:36And he's off. None the worse for wear.
0:31:44 > 0:31:48This phase of the work is based in the foothills of Mount Bosavi.
0:31:48 > 0:31:50But there's a series of trips in this expedition.
0:31:52 > 0:31:55Steve's embarking on another quest.
0:31:58 > 0:32:01He's heading east, to an island off the coast of New Guinea
0:32:01 > 0:32:03called New Britain.
0:32:05 > 0:32:11The forests here on New Britain are some of the most spectacular I've ever seen anywhere in the world.
0:32:11 > 0:32:16We're flying through a very deep, steep-sided gorge,
0:32:16 > 0:32:20with a whitewater river flowing right down through the middle of it.
0:32:20 > 0:32:23He's on his way to join a world class team of adventure cavers.
0:32:26 > 0:32:28These limestone hills are hollow.
0:32:28 > 0:32:33Under here is a honeycomb of caves which may stretch for miles.
0:32:33 > 0:32:34Their job is to explore them.
0:32:34 > 0:32:37There's just one problem -
0:32:37 > 0:32:40this is the only way into the caves.
0:32:42 > 0:32:45A whitewater river thunders from the entrance.
0:32:45 > 0:32:48And it's halfway up a jungle cliff.
0:32:48 > 0:32:50Oh, my life! Look at this!
0:32:50 > 0:32:53This must be it, this must be Mageni Cave.
0:32:53 > 0:32:55That's where we're going.
0:32:59 > 0:33:02The local village have turned out to meet Steve.
0:33:02 > 0:33:04Hello. Hello.
0:33:06 > 0:33:07Hello. Hee!
0:33:07 > 0:33:10This is the village of Ora,
0:33:10 > 0:33:13which is as close as we can get in the helicopter to the caves.
0:33:13 > 0:33:16So I guess we're gonna try and rouse some support here,
0:33:16 > 0:33:20try and get a few people to help us carry our stuff in, cos we've got an awful lot of it.
0:33:20 > 0:33:22We'd like to meet the head man,
0:33:22 > 0:33:25and get permission to be wandering around on what essentially is their land.
0:33:25 > 0:33:30Every piece of forest in New Guinea belongs to a local tribe.
0:33:32 > 0:33:37- Steve can't go anywhere without the consent of the chief.- Hello, hello.
0:33:37 > 0:33:42Have you ever been to the cave, Mageni Cave?
0:33:42 > 0:33:46- Yes.- And what do you think is inside the cave?
0:33:46 > 0:33:48HE SPEAKS IN LOCAL DIALECT
0:33:50 > 0:33:54It seems that there's a feeling, perhaps even a local myth,
0:33:54 > 0:33:57that there's a huge snake inside these caves.
0:33:57 > 0:33:59It would be very nice if it wasn't a local myth!
0:33:59 > 0:34:01If it was true, that would be great!
0:34:05 > 0:34:11One week in, and everyone at base camp has settled into a routine.
0:34:11 > 0:34:15But there's nothing regular about the animals coming in.
0:34:17 > 0:34:21It's a blue-tongued skink. He's beautiful.
0:34:23 > 0:34:26Every animal they find is recorded.
0:34:26 > 0:34:29Some of them are bright and beautiful. Some shy and camouflaged.
0:34:29 > 0:34:31What do you think it is?
0:34:31 > 0:34:33Little striped thrush.
0:34:33 > 0:34:34Little striped thrush.
0:34:34 > 0:34:38They've catalogued hundreds of animals.
0:34:38 > 0:34:41And at least seven of them are brand new species.
0:34:43 > 0:34:48Gordon has a new goal. Together with Muse Opiang, he'll be searching for the secretive mammals of the forest.
0:34:48 > 0:34:52To give us an overall view of the animals that live in this forest,
0:34:52 > 0:34:53we can't just use legwork,
0:34:53 > 0:34:57we have to put these traps out and find out what's living here.
0:34:57 > 0:35:01And we've got some kind of forest rat in here.
0:35:01 > 0:35:03I'll get him out and Muse can tell me exactly what it is.
0:35:03 > 0:35:05Do you like all the rats?
0:35:05 > 0:35:08- I like them.- Do you think they're ugly?- No, no, they're not ugly.
0:35:08 > 0:35:12Muse knows where to set the traps.
0:35:12 > 0:35:17And Gordon uses his tracking skills to search for signs.
0:35:19 > 0:35:22There's quite a kind of musky smell around here.
0:35:22 > 0:35:23Some big holes down there.
0:35:23 > 0:35:25I'm just gonna check it out.
0:35:25 > 0:35:28You're not only using your eyes and your ears to find animals,
0:35:28 > 0:35:32and quite often some animals give themselves away by their smell.
0:35:32 > 0:35:35There's definitely something around here or something that's been here.
0:35:35 > 0:35:38Have a look at this.
0:35:38 > 0:35:40Whooo!
0:35:40 > 0:35:41Spooky!
0:35:41 > 0:35:44It's almost a cave.
0:35:44 > 0:35:47Erm, there's a bit of a jump down.
0:35:47 > 0:35:49Luke, you might want to hand me the camera.
0:35:50 > 0:35:52Got it.
0:35:57 > 0:36:00He's found the entrance to a tunnel.
0:36:00 > 0:36:03Yeah. Cos they're a long way...
0:36:03 > 0:36:04Here, there's animal tracks.
0:36:04 > 0:36:08And see this muddy area? It's all smoothed down.
0:36:08 > 0:36:10You look around other areas,
0:36:10 > 0:36:13it doesn't have any of this surface mud that's just been smoothed over.
0:36:13 > 0:36:17Oh, there's a nut, kind of chewed fruit in there.
0:36:17 > 0:36:21This is a really good place to set up a little camera trap.
0:36:21 > 0:36:25Because without a doubt, there are animals coming and going from here.
0:36:25 > 0:36:29Muse helps to train a remote camera on the tunnel.
0:36:29 > 0:36:31- That's the right height.- OK.
0:36:31 > 0:36:34- You think that's good here?- Yes.
0:36:36 > 0:36:40Switch it on. OK, arming it in ten seconds.
0:36:44 > 0:36:46OK, I think we should just get out. It's running.
0:36:50 > 0:36:54Throughout the forest, remote cameras are placed to catch any mammals passing by.
0:36:56 > 0:36:59It's vital they find what lives here.
0:36:59 > 0:37:03They're surrounded by pristine forest,
0:37:03 > 0:37:05but the front line is getting closer.
0:37:10 > 0:37:14Just 20 miles south, the loggers have moved in.
0:37:17 > 0:37:20Every day, more trees disappear.
0:37:23 > 0:37:26George is pulling together all the evidence from the scientists.
0:37:26 > 0:37:31This report will be sent to government officials here,
0:37:31 > 0:37:38in the hope that it'll add into a plan for conserving the wildlife here.
0:37:38 > 0:37:40This is a critical issue now.
0:37:40 > 0:37:47This whole area in the foothills of Bosavi is a very special forest.
0:37:48 > 0:37:53The evidence is beginning to confirm that these forests are unique.
0:37:53 > 0:37:56And not only above the ground.
0:37:56 > 0:38:01To the east, the preparations for the underground exploration are well under way.
0:38:01 > 0:38:06Steve sets out on his trek to the cave entrance,
0:38:06 > 0:38:08with a little help from the villagers.
0:38:08 > 0:38:13They're heading to meet the team at their camp above the waterfall.
0:38:13 > 0:38:18The rest of the cavers have been there for a couple of days, preparing the gear.
0:38:23 > 0:38:28They've brought state-of-the-art equipment to map the river that flows through these caves.
0:38:28 > 0:38:32- ..more cave out there? - Exactly, it gives you an idea of what we're up against.
0:38:32 > 0:38:34As the only naturalist on the team,
0:38:34 > 0:38:37Steve's job is to search for any animals in the caves.
0:38:37 > 0:38:41We've got a remarkably strong team here.
0:38:41 > 0:38:45We have three members of the original expedition that came here just a couple of years ago.
0:38:45 > 0:38:48What's clear is that this is a gigantic cave system.
0:38:48 > 0:38:52This is a cave that goes on for a lot further than they managed to explore.
0:38:52 > 0:38:54That's our real aim, to push on into areas
0:38:54 > 0:38:59where they thought there might be the chance of something special, and try and find what's there.
0:38:59 > 0:39:03It's supposed to be the dry season. Heavy rains will flood the caves.
0:39:03 > 0:39:10This is really bad at the moment. The whole reason we planned to do this trip now
0:39:10 > 0:39:13is because the rains aren't due for at least another month.
0:39:13 > 0:39:17And if this carries on, it's gonna be more of a discomfort.
0:39:17 > 0:39:21There'll be no way we would get down the caves. And if we do, it would be very, very dangerous.
0:39:21 > 0:39:25At the moment, the worst thing we have to worry about is mud.
0:39:25 > 0:39:27The fact that all the kit is gonna die.
0:39:29 > 0:39:32Back at base camp, an injured bat's been brought in.
0:39:32 > 0:39:34Alanna's nursing it back to health.
0:39:38 > 0:39:41This is a common blossom bat.
0:39:41 > 0:39:44And it eats nectar with a very long tongue.
0:39:44 > 0:39:48And because it eats sugar, it needs sugar every 24 hours.
0:39:48 > 0:39:52- Will you do the honours? - Yeah, absolutely.
0:39:52 > 0:39:56I think if we can get a good meal into her now,
0:39:56 > 0:40:00and release her before it gets too warm, then she'll be fine.
0:40:00 > 0:40:03This bat is specially adapted to feeding on flowers.
0:40:04 > 0:40:07This fantastic tongue...
0:40:07 > 0:40:11- Look at that!- ..is rolled up inside its mouth and then it sticks it out
0:40:11 > 0:40:15down between the petals of a flower so that it can get to the nectar.
0:40:15 > 0:40:18Which is exactly what it's doing here,
0:40:18 > 0:40:20- it's going straight down the syringe tip.- Yup.
0:40:20 > 0:40:22Look at that.
0:40:22 > 0:40:27It's just gone from being nearly unconscious to really perky.
0:40:27 > 0:40:30That is... That is really nice.
0:40:30 > 0:40:32There we go, some strength back.
0:40:32 > 0:40:35We should release it as soon as possible,
0:40:35 > 0:40:38and then it won't be too hot for it to fly back to its day roost.
0:40:44 > 0:40:50It's day nine, and already the scientists have found ten species that are completely new to them.
0:40:50 > 0:40:53They're kept busy, day and night.
0:40:56 > 0:40:59Muse and Gordon have found a creature in one of their traps.
0:41:00 > 0:41:02It's a striped possum.
0:41:02 > 0:41:04Striped possum.
0:41:04 > 0:41:07They're famously feisty creatures,
0:41:07 > 0:41:08that are more than a match for bigger foe.
0:41:08 > 0:41:10Oh, wow! He's a beauty!
0:41:10 > 0:41:13They're marsupials, raising their babies in a pouch.
0:41:13 > 0:41:16And for defence, can let out very strong smells.
0:41:19 > 0:41:24He's black and white like a skunk, and he actually smells like a skunk - very strong, musty odour.
0:41:24 > 0:41:28You can see that finger, it's quite extraordinary.
0:41:28 > 0:41:31There are few animals in the world that have that kind of adaptation.
0:41:31 > 0:41:34The long finger is for winkling grubs out of holes.
0:41:38 > 0:41:43We'll weigh him, measure him and then take him back to exactly where we found him.
0:41:43 > 0:41:46Let's measure the tail first.
0:41:47 > 0:41:49330.
0:41:49 > 0:41:53For the base, left to the tip.
0:41:53 > 0:41:57With the vital statistics taken, it's time to release him.
0:41:57 > 0:41:59Right, this is the tricky part.
0:41:59 > 0:42:02You can see how sharp his teeth are.
0:42:02 > 0:42:05I really want to avoid getting bitten.
0:42:05 > 0:42:07Owww!
0:42:07 > 0:42:09Oh!
0:42:09 > 0:42:13That's a bit of a nip. OK, can I nick that other glove just in case?!
0:42:13 > 0:42:16This glove is made from the same material
0:42:16 > 0:42:19that bullet-proof vests and stab jackets are made from.
0:42:19 > 0:42:23And he's actually causing quite a bit of pain so I'm gonna take him out and release him.
0:42:23 > 0:42:27OK, I reckon as soon as his feet touch, he's gonna be off.
0:42:27 > 0:42:29OK, pal. There you go.
0:42:29 > 0:42:31Oh, look at that!
0:42:31 > 0:42:34Yeah, that's good. He's much happier now.
0:42:41 > 0:42:45700 miles to the east, Steve and the team are abseiling down to the mouth of the cave.
0:42:48 > 0:42:50We've seen the cave from the air.
0:42:50 > 0:42:53But to stand here and for the first time really be able to hear
0:42:53 > 0:42:56the sound of it raging beneath us is something else.
0:43:00 > 0:43:03It's an 80-metre drop to the entrance.
0:43:04 > 0:43:06Oh, wow!
0:43:19 > 0:43:24It's not a very usual view, hanging above a waterfall.
0:43:24 > 0:43:31And below it there's this majestic drop down to the pool beneath.
0:43:31 > 0:43:35I'm not liking where these ropes are bringing me down though.
0:43:35 > 0:43:37I'm gonna be right in the waterfall.
0:43:39 > 0:43:41Whoa!
0:43:41 > 0:43:44Just hope I can find somewhere
0:43:44 > 0:43:47to get my footing on here.
0:43:47 > 0:43:49Ho-ho!
0:43:51 > 0:43:54I just do not wanna slip now.
0:44:04 > 0:44:09Out there, everything's green and magical.
0:44:09 > 0:44:14In there, it's all frankly a little bit frightening.
0:44:21 > 0:44:26In the lab, George has been distracted from his job of writing the report.
0:44:26 > 0:44:29Somebody brought me back these in a little bag.
0:44:29 > 0:44:33I'm not sure what they are... Oh, wow. Look!
0:44:33 > 0:44:35Long-horned beetles.
0:44:35 > 0:44:36And they're mating!
0:44:36 > 0:44:39Oh, my God! That's the male and the female.
0:44:39 > 0:44:42- Alanna? Have you seen these?- Yeah?
0:44:42 > 0:44:44- I found them for you, George. - It was you who found them?
0:44:44 > 0:44:48Oh, thank you very much. They're absolutely gorgeous.
0:44:48 > 0:44:52Actually, I should be slightly anxious about this, because they have got very, very sharp jaws
0:44:52 > 0:44:55and if it happens to sink it into my earlobe,
0:44:55 > 0:44:57you will hear...
0:44:57 > 0:45:00Ooh, squeaking.
0:45:00 > 0:45:02Oh, they're squeaking.
0:45:02 > 0:45:06This being the land of squeaking beetles.
0:45:06 > 0:45:08BEETLES SQUEAK QUIETLY
0:45:11 > 0:45:14The cavers are pushing their way up the white-water river.
0:45:17 > 0:45:20The current is strong.
0:45:20 > 0:45:23They can't afford to put a foot wrong.
0:45:30 > 0:45:34Oh, this is unbelievable!
0:45:35 > 0:45:38They're now half a mile into the cave and face a huge obstacle,
0:45:38 > 0:45:41a waterfall swollen by heavy rains.
0:45:41 > 0:45:44This is the largest waterfall that we know of
0:45:44 > 0:45:47in the whole of the Mageni cave river system.
0:45:47 > 0:45:50The entire volume of the river is flowing over this waterfall,
0:45:50 > 0:45:52and it's a real crux point in the cave.
0:45:52 > 0:45:55If you can't get beyond this, then you really have been stymied,
0:45:55 > 0:45:57you know, you can't get any further.
0:46:00 > 0:46:04Back at camp, Gordon starts to sort through the thousands of pictures
0:46:04 > 0:46:09captured by the remote cameras.
0:46:09 > 0:46:13The thing about this system is you can't review it in the field, so it's quite exciting.
0:46:13 > 0:46:15There's a Christmas morning moment.
0:46:15 > 0:46:17You come back with this little memory card,
0:46:17 > 0:46:21put it in the computer and then you find out exactly what you've got.
0:46:21 > 0:46:26Sometimes it's a pair of socks and sometimes it's a Scalextric.
0:46:30 > 0:46:32Hmm.
0:46:32 > 0:46:34At first it looks like socks.
0:46:35 > 0:46:37Any movement triggers the camera.
0:46:40 > 0:46:47One of the curiosities of New Guinea is there are hardly any large mammals living on the jungle floor.
0:46:47 > 0:46:49A rat.
0:46:49 > 0:46:51You've got giant rats here.
0:46:51 > 0:46:54Rats that are bigger than domestic cats.
0:46:54 > 0:46:58The last camera trap to check is from the tunnel entrance.
0:47:01 > 0:47:05Another rat. I think that's a different species.
0:47:08 > 0:47:10Hmm.
0:47:11 > 0:47:14Then something very special,
0:47:14 > 0:47:17one of the most secretive creatures in New Guinea.
0:47:17 > 0:47:21Look! That is a cuscus.
0:47:21 > 0:47:24I knew it! Look, look, look. I do not believe that.
0:47:24 > 0:47:28He's just having a good old root around.
0:47:28 > 0:47:30These images were taken at five in the morning.
0:47:30 > 0:47:33Cuscus are only active at night.
0:47:33 > 0:47:37This one's returning to the cave, where it must spend the day.
0:47:37 > 0:47:38Oh, goodness me.
0:47:38 > 0:47:43I would have absolutely have loved to have been there.
0:47:44 > 0:47:47It's an important find for the team.
0:47:47 > 0:47:50Cuscus are so shy they're rarely seen.
0:47:50 > 0:47:54At dusk, Gordon heads out to try and capture one on camera.
0:47:54 > 0:47:57During the day, they'll either be asleep in the trees,
0:47:57 > 0:47:59and more often than not they'll be in a hole,
0:47:59 > 0:48:01whether that's a hole in a tree,
0:48:01 > 0:48:04a hole in the ground or underneath these big boulders.
0:48:04 > 0:48:07I've got lots of different camera systems that we can pretty much
0:48:07 > 0:48:11check out every option at night time and try and get some shots of them.
0:48:12 > 0:48:17At the waterfall, Steve's putting his skills as a climber to good use.
0:48:17 > 0:48:19He's leading the way up.
0:48:19 > 0:48:22An old rope has been left by the previous expedition.
0:48:22 > 0:48:24It feels pretty good.
0:48:24 > 0:48:30But it's been battered by the waterfall for the last two years
0:48:30 > 0:48:34so I can't really afford to risk my life on it.
0:48:34 > 0:48:37A camera is attached to Steve's helmet.
0:48:38 > 0:48:41All I can see is spray.
0:49:15 > 0:49:19Can't see anything. Rocks.
0:49:28 > 0:49:31Yeah! That's it!
0:49:31 > 0:49:33Lots of loose rock.
0:49:36 > 0:49:38Whoa!
0:49:38 > 0:49:42I have a feeling this is going to be the crux.
0:49:44 > 0:49:48That overhanging right in the waterfall.
0:49:52 > 0:49:56It's now pitch black and Gordon is pushing into unknown territory
0:49:56 > 0:50:02to find and film the elusive cuscus he'll use only infra-red light.
0:50:02 > 0:50:05Got lots of noise up in the top of this tree.
0:50:06 > 0:50:10Not the cuscus, but giant fruit bats.
0:50:10 > 0:50:14We've got these fruit bats feeding on figs.
0:50:15 > 0:50:17It's a long way up.
0:50:17 > 0:50:21You can see the way that they're using their wings,
0:50:21 > 0:50:25their claws, to clamber about in the tree tops.
0:50:25 > 0:50:30Because he's using infrared light, the bats are completely undisturbed.
0:50:30 > 0:50:33Oh, look at them squabbling!
0:50:37 > 0:50:40Oh, oh! Fight, fight! There's two fighting there.
0:50:40 > 0:50:43It's amazing that there's actually fisticuffs up there,
0:50:43 > 0:50:46you'd think there'd be enough to go round,
0:50:46 > 0:50:47but evidentially not.
0:50:47 > 0:50:52Everyone's just defending their little patch of figs.
0:50:55 > 0:50:59Oh, look, he's just testing with his mouth to see how ripe that is.
0:51:02 > 0:51:07But what these bats have that I haven't seen on other fruit bats
0:51:07 > 0:51:10is this enormous thumb, this big hook,
0:51:10 > 0:51:13and they're using those hooks
0:51:13 > 0:51:15to clamber about in the tree tops.
0:51:15 > 0:51:17Incredibly agile.
0:51:18 > 0:51:22These are key animals in the ecology of the rainforest,
0:51:22 > 0:51:26feeding on fruit and dispersing the seeds up to 30 miles away.
0:51:26 > 0:51:29It does mean filming them has its down sides.
0:51:29 > 0:51:33I was thinking that a fig on the head was the worst thing that we could get,
0:51:33 > 0:51:36but probably bat poo is a bit worse.
0:51:37 > 0:51:41Oh! There you... Ugh! Ugh!
0:51:41 > 0:51:45Seems that figs have the same effect on fruit bats as they do on humans.
0:51:52 > 0:51:56At last Steve has made it up the jagged rocks of the waterfall.
0:51:56 > 0:51:58That's more like it!
0:51:59 > 0:52:02The water-sodden team haul themselves up.
0:52:05 > 0:52:10At the top of the falls they start the painstaking work of mapping the underground river.
0:52:10 > 0:52:14Lasers measure to a millimetre the size of the ancient chamber.
0:52:19 > 0:52:22- How's that?- Yeah.
0:52:23 > 0:52:25Then it's on again.
0:52:25 > 0:52:28They must find a place to sleep before they get exhausted.
0:52:28 > 0:52:31Oh, it's cold!
0:52:35 > 0:52:40It's now very late, and Gordon's pushing deeper into the jungle on the track of the cuscus.
0:52:40 > 0:52:44There's something in the trees.
0:52:44 > 0:52:47I just got some eye shine directly above me.
0:52:47 > 0:52:50I think it's round about here.
0:52:50 > 0:52:56Power on. Oh, there you go, right in the middle there.
0:52:56 > 0:52:58At last, Gordon's found his animal.
0:52:58 > 0:53:00You little beauty!
0:53:00 > 0:53:02It's a cuscus.
0:53:02 > 0:53:07And there he is just happily sitting on the branches a long, long way up.
0:53:07 > 0:53:11The size of a domestic cat, cuscus are nocturnal,
0:53:11 > 0:53:14moving high in the canopy with their babies secure in their pouches.
0:53:14 > 0:53:16And you get ground cuscus
0:53:16 > 0:53:19and its hands are less well developed for climbing,
0:53:19 > 0:53:23but this one is very, very comfortable in the trees.
0:53:26 > 0:53:31It's such an unusual animal. It doesn't really bear any resemblance
0:53:31 > 0:53:35to any animals that we would commonly know.
0:53:36 > 0:53:40You can see he's got this big, long tail.
0:53:40 > 0:53:43It not only helps him balance as he moves through the trees,
0:53:43 > 0:53:46but it's a prehensile tail, he can use that as an extra limb.
0:53:46 > 0:53:51And you can just make out that the end of his tail is naked,
0:53:51 > 0:53:56so he can wrap that tail around branches and use it as a fifth arm.
0:53:59 > 0:54:04They're quite a bit like teddy bears with a big long tail.
0:54:05 > 0:54:09They're quite beautiful. They're really nice animals.
0:54:09 > 0:54:14A first small glimpse of the cuscus, but a great success for Gordon.
0:54:16 > 0:54:22- Oh, there he goes!- Then it's off, disappearing into the forest.
0:54:24 > 0:54:26All right, Steve?
0:54:26 > 0:54:30The cavers are now two miles into the mountain,
0:54:30 > 0:54:34under a hundred million tonnes of rock.
0:54:35 > 0:54:39It's like being inside the home of some massive alien,
0:54:39 > 0:54:41the walls all dripping with slime.
0:54:41 > 0:54:44And they're not alone.
0:54:49 > 0:54:51Look at that.
0:54:53 > 0:54:57It's a very bizarre little crab.
0:54:57 > 0:55:01It's evolved in isolation here in this cave.
0:55:02 > 0:55:04These are the kind of creatures
0:55:04 > 0:55:07that turn out to be absolutely new to science.
0:55:07 > 0:55:11The eyes have faded away to almost nothing.
0:55:11 > 0:55:15They're of no use whatsoever in a place like this.
0:55:15 > 0:55:17In fact,
0:55:17 > 0:55:20this will be the first light that this crab will ever have experienced.
0:55:20 > 0:55:24I really wasn't expecting to find any life much past the first hundred metres of the cave.
0:55:24 > 0:55:28So this is... This is quite a find.
0:55:29 > 0:55:32They can't stop for long.
0:55:34 > 0:55:37Although they're now very tired they must push further into the cave
0:55:37 > 0:55:40to find a dry spot to make camp.
0:55:43 > 0:55:45Getting anywhere is tough.
0:55:55 > 0:55:57In the calm of the jungle lab,
0:55:57 > 0:56:01George tallies up the remarkable discoveries they've made.
0:56:04 > 0:56:06We're a third of the way into the trip and so far
0:56:06 > 0:56:09we've got one new species of bat,
0:56:09 > 0:56:11we've got certainly two new species of frog
0:56:11 > 0:56:14and two more that are potentially new species.
0:56:14 > 0:56:17We've got three species of fish new,
0:56:17 > 0:56:20insects and spiders, five to eight, possibly ten.
0:56:20 > 0:56:22A lot more to come.
0:56:22 > 0:56:25The list expands quicker than he expects.
0:56:25 > 0:56:27Hi, Alan. What are you doing?
0:56:27 > 0:56:31Alan's come across something just a stone's throw from the lab.
0:56:31 > 0:56:34Well, I just caught a very pretty gecko.
0:56:34 > 0:56:36Oh, that's gorgeous!
0:56:36 > 0:56:38Is that the first one you've got of those here?
0:56:38 > 0:56:41Now, I've got to ask you this, have you seen that before here?
0:56:41 > 0:56:43- We have not. - Have you seen it anywhere?
0:56:43 > 0:56:47No, I'm almost certain this is a new species.
0:56:47 > 0:56:51- Not only that, but it's a girl. - How do you know? - Well, you can see the eggs.
0:56:51 > 0:56:54- That's the eggs, is it?- Yeah, you can see them right through the body.
0:56:54 > 0:56:58Transparent? That is absolutely gorgeous!
0:56:58 > 0:57:00Oh, my goodness. That's amazing.
0:57:00 > 0:57:03Feels absolutely lovely, doesn't it?
0:57:03 > 0:57:05It's like velvet.
0:57:07 > 0:57:09The tail is quite strikingly banded
0:57:09 > 0:57:11and you can see how well they blend in.
0:57:11 > 0:57:16Alan's gecko is like icing on the cake for the team.
0:57:19 > 0:57:24Two weeks in and the expedition's exceeded all expectations.
0:57:33 > 0:57:36For the cavers, there's no celebrations.
0:57:36 > 0:57:40They're now deep in the bowels of the mountain
0:57:40 > 0:57:41and there's no place to stop.
0:57:41 > 0:57:45The river is as strong as ever, sapping their energy.
0:57:45 > 0:57:49Exhausted, they struggle on into the darkness.
0:57:59 > 0:58:05Later in the expedition, the team enlists the help of a local tribe
0:58:05 > 0:58:07in the search for exotic birds of paradise...
0:58:07 > 0:58:09Jeez, there's two of them! There's two of them. Wow!
0:58:12 > 0:58:15- They witness an exploding volcano... - Grief!
0:58:15 > 0:58:20Enter the lost world of the jungle crater...
0:58:20 > 0:58:23Oh, soaking!
0:58:23 > 0:58:25And Steve discovers a new flooded cave
0:58:25 > 0:58:28in the depths of the underworld.
0:58:45 > 0:58:47Subtitles by Red Bee Media Ltd