0:00:04 > 0:00:07Deep in the heart of the island of Borneo
0:00:07 > 0:00:12is a lost world of mountains, jungles and ravines.
0:00:12 > 0:00:16It hides an abundance of wildlife.
0:00:16 > 0:00:19And it's disappearing. Fast.
0:00:20 > 0:00:25Now the BBC has assembled a team of jungle specialists
0:00:25 > 0:00:28to explore this great unknown wilderness...
0:00:28 > 0:00:30..before it's too late.
0:00:33 > 0:00:36Oh, look at them. Fantastic.
0:00:38 > 0:00:42- Oh, my God.- For forty days, they'll be living deep in this forest.
0:00:42 > 0:00:44A young male, look.
0:00:44 > 0:00:50We've made a real decision to go to places deliberately that people haven't been to before.
0:00:50 > 0:00:56Their aim - to track down and catalogue the extraordinary animals that live here.
0:00:58 > 0:01:00This one's at least two metres.
0:01:00 > 0:01:03Avoiding the ones that are tracking THEM down.
0:01:05 > 0:01:07I want my mum!
0:01:21 > 0:01:26It's a tough walk in, as hot as a sauna, and just as humid.
0:01:33 > 0:01:37Their destination, a base camp built specially for the team.
0:01:40 > 0:01:42Just as they're nearing camp,
0:01:42 > 0:01:45a helicopter brings in two tons of climbing gear,
0:01:45 > 0:01:46food and emergency medical kit.
0:01:55 > 0:01:59The helicopter drops the supplies in the only place it can.
0:01:59 > 0:02:01A nearby river beach.
0:02:08 > 0:02:12The team includes Gordon Buchanan and Justine Evans,
0:02:12 > 0:02:16wildlife cameramen fresh from filming Planet Earth.
0:02:31 > 0:02:33For the first phase of the expedition,
0:02:33 > 0:02:38this will be laboratory and living quarters for the team of climbers, cameramen and scientists.
0:02:39 > 0:02:43They've brought along state-of-the-art filming kit.
0:02:43 > 0:02:48But the tropical heat and humidity will test the gear, and the people, to the very limit.
0:02:54 > 0:02:56It's supposed to be the dry season.
0:02:56 > 0:02:59- It's pouring rain. - You have to shout, I'm afraid.
0:02:59 > 0:03:02It's pouring rain, you can hardly hear yourself think,
0:03:02 > 0:03:04and I hope I put all my stuff away properly.
0:03:04 > 0:03:06I don't know how long this can last,
0:03:06 > 0:03:10if it rained like this at home, it could only last for five minutes,
0:03:10 > 0:03:11but here, it could go on for hours.
0:03:11 > 0:03:16The rain's coming in on my hammock, and all my stuff's getting wet.
0:03:16 > 0:03:20The first injuries are being treated by the ex-army medics.
0:03:20 > 0:03:25Here, even the smallest wounds quickly turn septic.
0:03:47 > 0:03:50By the next morning, the storm has passed.
0:03:50 > 0:03:53Gordon served his apprenticeship in the Amazon.
0:03:53 > 0:03:56He lived there for four years.
0:03:56 > 0:04:01Rainforests definitely are one of the most uncomfortable environments,
0:04:01 > 0:04:05it is just like a big compost heap, and things just...
0:04:05 > 0:04:07If you don't move, you rot.
0:04:08 > 0:04:12First light is the best time to work, before temperatures soar.
0:04:12 > 0:04:13OK.
0:04:14 > 0:04:17Justine is on her first recce of the forest.
0:04:21 > 0:04:25Most of Tara's work is in deserts and mountains, not rainforests.
0:04:25 > 0:04:29Well, at some point, I have to put these wet clothes back on,
0:04:29 > 0:04:32and as you can see, they're still wringing wet,
0:04:32 > 0:04:35they've been hanging up there all night.
0:04:35 > 0:04:38They're no drier than they were last night,
0:04:38 > 0:04:43and the theory is that we should take these dry clothes off,
0:04:43 > 0:04:48and keep them dry for tonight and put these wet, cold, clammy clothes on,
0:04:48 > 0:04:51and I mean, right from the knickers up.
0:04:53 > 0:04:57Dr Tara Shine is an environmental scientist.
0:04:57 > 0:05:02She's here to pull together all the discoveries on the expedition.
0:05:02 > 0:05:05I advise primarily, governments,
0:05:05 > 0:05:09on what they should be doing to take better account of the environment
0:05:09 > 0:05:12in their policies and in their planning.
0:05:12 > 0:05:15I'm fascinated with the world and how it works,
0:05:15 > 0:05:20and how do we look after our beautiful, fabulous planet in the context of the changing world.
0:05:20 > 0:05:24Half of all species in the world live in rainforests.
0:05:24 > 0:05:26They teem with life.
0:05:29 > 0:05:32But, now more than ever, they're threatened,
0:05:32 > 0:05:35even in this far-flung region, where humans rarely venture.
0:05:35 > 0:05:38When we're walking around here, looking for things,
0:05:38 > 0:05:42we're stepping on trails that nobody has been on before.
0:05:42 > 0:05:46At night, we're shining our torches on things that people have never seen before.
0:05:50 > 0:05:55The base camp is deep in the lost valley of Imbak,
0:05:55 > 0:05:58a canyon with massive walls of rock on either side,
0:05:58 > 0:06:01protecting the untouched forest within.
0:06:04 > 0:06:06For the first phase of the expedition,
0:06:06 > 0:06:10the team will track down and film the animals that live here
0:06:10 > 0:06:14in the hope they can raise the conservation status of this remote canyon.
0:06:22 > 0:06:27Justine has heard a pair of gibbons singing to each other high above.
0:06:27 > 0:06:30GIBBONS CHIRRUP OVERHEAD
0:06:31 > 0:06:35We're going to find the gibbons, apparently they're just above the trail.
0:06:35 > 0:06:37We've got to...in a real hurry.
0:06:37 > 0:06:39Might not stay there very long.
0:06:40 > 0:06:44Junior Laredo and a team of Malaysian naturalists are part of the expedition.
0:06:44 > 0:06:47This morning, they're tracking a gibbon family,
0:06:47 > 0:06:49as they swing through the canopy.
0:06:51 > 0:06:55We just saw them moving through. They're probably not far.
0:06:57 > 0:07:02Gibbons are easy to hear, but notoriously difficult to film.
0:07:02 > 0:07:06It's a tough test, even for a seasoned camerawoman like Justine.
0:07:06 > 0:07:10They spend most of their time nearer the tops of trees,
0:07:10 > 0:07:12and they have the opposite of vertigo,
0:07:12 > 0:07:15I think. If they come to the ground, they're terrified.
0:07:15 > 0:07:19Yeah, we found the gibbons, I didn't manage to get a shot,
0:07:19 > 0:07:23but we found where they are, and I'm gonna head back to base now. Over.
0:07:25 > 0:07:30So, you heard them, and you thought you could see them jumping from tree to tree.
0:07:30 > 0:07:32Yeah, but they were way up in the distance,
0:07:32 > 0:07:35so we left Junior out to just keep tabs on them,
0:07:35 > 0:07:37try and find out where they're going to sleep.
0:07:37 > 0:07:41I think, at this stage, it's more important that we do that,
0:07:41 > 0:07:45and I did hear a proper duet in that area, so there must be a pair.
0:07:45 > 0:07:49- If you want shots, you have to get them from the platform.- Yeah.
0:07:49 > 0:07:53- Otherwise, it'll just be a glimpse of moving leaves, with a bit of fur. - Exactly.
0:07:53 > 0:07:57The gibbons have never seen people before.
0:07:57 > 0:08:01Justine has no idea how they'll react.
0:08:01 > 0:08:02And then, you follow Justine.
0:08:02 > 0:08:05- Junior to Tara, come in, over. - Junior, it's Tara.
0:08:05 > 0:08:10Tara, we've just discovered a very fresh track of clouded leopard.
0:08:10 > 0:08:13500 metres from the camp. Over.
0:08:13 > 0:08:15That's brilliant, Junior.
0:08:15 > 0:08:17I mean, fresh, as in 24 hours?
0:08:17 > 0:08:21Probably just after the rain. Over.
0:08:21 > 0:08:24Wow, and only 500 metres from here?
0:08:24 > 0:08:25500 metres from the camp. Over.
0:08:25 > 0:08:29- What is it?- It's brilliant news. Clouded leopard tracks.
0:08:29 > 0:08:31- You're joking. - Fresh ones, like 24 hours.
0:08:31 > 0:08:34He thinks sometime during the rains last night.
0:08:34 > 0:08:36- Whereabouts?- 500 metres away.
0:08:36 > 0:08:39Now, we have to figure out a way... How can we see them?
0:08:40 > 0:08:42The clouded leopard.
0:08:42 > 0:08:47The most elusive and secretive of Borneo's carnivores.
0:08:48 > 0:08:53Finding and filming it would be a real coup for big cat expert Gordon.
0:08:53 > 0:08:55Wow! There it is, that's the first one.
0:08:55 > 0:09:00- That's incredibly fresh.- That's the great thing about the rains.
0:09:00 > 0:09:03It makes this a total mulch, and perfect for tracking stuff.
0:09:03 > 0:09:05So, how do you know this is a leopard print?
0:09:05 > 0:09:09Looking at the size, I reckon it's a huge, huge cat.
0:09:09 > 0:09:11So, how long about, do you think?
0:09:11 > 0:09:16So, body size will be like, that long, with an extended fluffy tail,
0:09:16 > 0:09:20and with this claw mark, it's kind of heavy cat, for sure.
0:09:20 > 0:09:21This is so encouraging,
0:09:21 > 0:09:26but this is just an indication that they're here.
0:09:26 > 0:09:30Trying to get images of them is going be the next big step.
0:09:35 > 0:09:40Justine's already on her next step to tracking down the gibbons.
0:09:40 > 0:09:44She's going to build a platform up one of the giant forest trees.
0:09:44 > 0:09:49Her crossbow fires a line over a high branch.
0:09:49 > 0:09:52Hey, perfect! Got it right through the right branch.
0:09:52 > 0:09:54I was really relieved at that, actually,
0:09:54 > 0:09:57I thought it was going to be a nightmare.
0:09:57 > 0:09:59This is just beginning.
0:09:59 > 0:10:04The hot and sweaty job of carrying the metal platform up the steep slopes
0:10:04 > 0:10:07falls to biologist and mountaineer Steve Backshall.
0:10:07 > 0:10:10It's about the weight of a small child.
0:10:11 > 0:10:14And made of solid aluminium.
0:10:16 > 0:10:20And I'm very glad that it's not me that's going to be living on it for three weeks.
0:10:21 > 0:10:23Back on the trail of the clouded leopard,
0:10:23 > 0:10:26Tara's making a plaster cast of the footprint.
0:10:28 > 0:10:31Having physical proof it lives here is vital.
0:10:33 > 0:10:39The clouded leopard is one of the rarest and most endangered animals in Borneo.
0:10:39 > 0:10:42So, maybe, if we find animals like the clouded leopard,
0:10:42 > 0:10:46we might be able to raise the status of this area, their unique habitat,
0:10:46 > 0:10:48so that it can be protected for posterity.
0:10:52 > 0:10:57The canyon may be remote today, but could be threatened tomorrow.
0:10:57 > 0:11:02Once, this great southeast Asian island was all rainforest,
0:11:02 > 0:11:05but every year, a million trees are felled.
0:11:05 > 0:11:08Every year, the plantations creep closer.
0:11:08 > 0:11:12Down in the lowlands, the rows of oil palm start,
0:11:12 > 0:11:15and stretch as far as the eye can see.
0:11:16 > 0:11:2020 years ago, this was all rainforest.
0:11:28 > 0:11:32For the team to help conserve the canyon as a nature reserve,
0:11:32 > 0:11:36they need evidence that it's home to a rich variety of wildlife.
0:11:38 > 0:11:45From now on, Justine will spend each and every day perched on this square of aluminium.
0:11:45 > 0:11:48It's always a bit nerve-wracking when you go up a tree,
0:11:48 > 0:11:49having not climbed for a while.
0:11:59 > 0:12:02It's a lot higher than it looked from the ground.
0:12:02 > 0:12:05The tree is higher than the Statue Of Liberty.
0:12:06 > 0:12:10If we see any gibbons, I think they're going to be nervous.
0:12:10 > 0:12:13It's a remote spot, there hasn't been anyone here,
0:12:13 > 0:12:15let alone people up trees.
0:12:17 > 0:12:19With the help of the climbing team,
0:12:19 > 0:12:23the platform is hauled up the forest giant.
0:12:23 > 0:12:25Probably a little bit higher.
0:12:28 > 0:12:32Rainforest trees can grow over 70 metres high,
0:12:32 > 0:12:34but they are precarious,
0:12:34 > 0:12:36with their shallow roots clinging to thin soils.
0:12:36 > 0:12:41If a storm blows in, they can easily crash to the ground.
0:12:43 > 0:12:49But if you're serious about finding gibbons, this is the only place to be.
0:12:49 > 0:12:52Now, Justine must sit and wait.
0:13:08 > 0:13:13At base camp, another expedition member is arriving.
0:13:13 > 0:13:16All the way from the University of Oxford,
0:13:16 > 0:13:19Dr George McGavin, one of the world's great specialists in insects.
0:13:19 > 0:13:20How are you, George?
0:13:21 > 0:13:24Some fantastic insects on the way up.
0:13:24 > 0:13:25Beautiful, beautiful stuff.
0:13:25 > 0:13:27Last night it rained, George.
0:13:27 > 0:13:30All the insects came into where we were sitting,
0:13:30 > 0:13:34and there was this huge spider, just chomping and chomping.
0:13:40 > 0:13:46After the evening meal, George starts a hunt for a small but deadly predator.
0:13:46 > 0:13:48The scorpion.
0:13:48 > 0:13:52We'll take a few pots, and we need a rather special torch,
0:13:52 > 0:13:56and we need a rather special pair of glasses as well.
0:13:56 > 0:13:59How this works, it's an ultra-violet torch,
0:13:59 > 0:14:02and it makes things fluoresce,
0:14:02 > 0:14:07and if I shine it under here, you'll see loads of things shining.
0:14:07 > 0:14:08Tags, and labels, and stuff,
0:14:08 > 0:14:12which are reacting and fluorescing in the ultraviolet light,
0:14:12 > 0:14:15and that's exactly what scorpions do.
0:14:15 > 0:14:17Oh, look!
0:14:17 > 0:14:20When you see them, it just stands out at you.
0:14:20 > 0:14:22It just jumps out!
0:14:22 > 0:14:27There's our first scorpion within ten feet of the camp. Oop!
0:14:27 > 0:14:30- The camp's toilet is also occupied. - Oh, there he is.
0:14:30 > 0:14:34It's either a piece of toilet paper, or it's a very large scorpion.
0:14:34 > 0:14:37In fact, I can actually see its claw from here.
0:14:37 > 0:14:39There we go. Oh! Where'd he go?
0:14:39 > 0:14:41There he is, there he is.
0:14:41 > 0:14:46Easy, boy. Now, that one's gonna hurt. It's got quite thin claws.
0:14:46 > 0:14:52As a general rule, if a scorpion has got thin claws and a fat tail, that's bad news,
0:14:52 > 0:14:55because it uses its venom rather than its physical strength.
0:14:55 > 0:14:57But you can see how it's quite aggressive.
0:14:57 > 0:15:00I mean, it's rearing up in a threat display there,
0:15:00 > 0:15:03with the claws open, and the sting held high there.
0:15:03 > 0:15:06There! It had a go at my blade, there.
0:15:06 > 0:15:08That's what we share the toilets with.
0:15:10 > 0:15:16This is actually the most fun I've had on a toilet, I think, for a long time.
0:15:19 > 0:15:23The rest of the team are heading out in search of a much larger predator.
0:15:23 > 0:15:26The clouded leopard.
0:15:27 > 0:15:31It is a really big deal that we've found those marks here,
0:15:31 > 0:15:32and so close to camp,
0:15:32 > 0:15:35because they are one of the rarest cats in the world,
0:15:35 > 0:15:38and we've got one living very close to the camp.
0:15:40 > 0:15:44Separate groups of us have gone out tonight, in different directions,
0:15:44 > 0:15:47trying to see if we can find the clouded leopard.
0:15:49 > 0:15:53Using spotlights is actually one of the best ways of finding things at night time,
0:15:53 > 0:15:56because, more often than not, if you catch a cat,
0:15:56 > 0:15:59particularly in these spotlights, they just stop.
0:15:59 > 0:16:03You get this eye shine, the light bouncing back off their eyes.
0:16:05 > 0:16:10As the search for the leopard takes them deeper into the jungle, Gordon comes under attack.
0:16:10 > 0:16:12Oh, get off.
0:16:12 > 0:16:14From bloodsucking leeches.
0:16:14 > 0:16:18I really don't like them. They're quite abhorrent, really.
0:16:18 > 0:16:20It's got its teeth into me.
0:16:20 > 0:16:22I have to kind of pull it off with my nail.
0:16:22 > 0:16:27As soon as they latch on, you can't even get them off your finger, look,
0:16:27 > 0:16:31and he'll work his way to a nice warm area.
0:16:34 > 0:16:37The leopard is so well-camouflaged,
0:16:37 > 0:16:41the team could be walking right past one, and not notice.
0:16:41 > 0:16:48To help track it down, Gordon has brought a piece of high technology to this ancient forest.
0:16:48 > 0:16:52This is the first night I've used the thermal imaging camera.
0:16:52 > 0:16:57Anything that's hotter than average is gonna show a bright orange,
0:16:57 > 0:17:00so, warm-blooded mammals are gonna stick out like a sore thumb.
0:17:05 > 0:17:09Shall I put this on again? Shall I have a quick look?
0:17:09 > 0:17:14- Okey-dokey. - Justine's team see some eye shine.
0:17:14 > 0:17:17- I saw the red eyes.- Yeah. - Just, just see down...
0:17:17 > 0:17:21It's not the leopard, but they've found its prey.
0:17:21 > 0:17:24Two tiny mouse deer.
0:17:24 > 0:17:26It's a lesser mouse deer.
0:17:26 > 0:17:28Leopard dinner.
0:17:28 > 0:17:30Well spotted!
0:17:31 > 0:17:35I've got to be up at 4:30, so we're gonna cut it short.
0:17:35 > 0:17:39- Because that gives me precisely six hours' sleep.- All right.
0:17:42 > 0:17:45Gordon presses deeper into the jungle,
0:17:45 > 0:17:47and makes an extraordinary find.
0:17:49 > 0:17:55There's a tarsier just about five metres in front of me.
0:17:55 > 0:17:57It's a little, little red dot,
0:17:57 > 0:18:00orange dot, right in the middle of the frame.
0:18:01 > 0:18:04OK, I'm going to move a little bit closer,
0:18:04 > 0:18:06try and get further down the bank.
0:18:08 > 0:18:10The tarsier.
0:18:10 > 0:18:13Secretive and silent, with huge eyes,
0:18:13 > 0:18:16to make out predators hunting it in the darkness.
0:18:16 > 0:18:20It's said that if humans had eyes the size of tarsiers',
0:18:20 > 0:18:22they'd be as big as apples.
0:18:24 > 0:18:26They can nearly rotate their head 360 degrees.
0:18:26 > 0:18:30They can look all the way around, all the way around that way.
0:18:32 > 0:18:36A cousin of the bush baby, the tarsier is an important find.
0:18:36 > 0:18:39It's never been seen in this canyon before.
0:18:39 > 0:18:44To sit this close to a wild tarsier is fantastic. Really good.
0:18:52 > 0:18:57Almost midnight, and the team is still searching for the leopard,
0:18:57 > 0:18:59when suddenly, everything changes.
0:18:59 > 0:19:02LOUD THUNDER
0:19:03 > 0:19:09- We have to move.- This is starting to get a bit dangerous here?- Yeah.
0:19:09 > 0:19:13Rain, no problem. Rain with wind, big problem.
0:19:13 > 0:19:17Base camp, base camp, this is Junior, come in, over.
0:19:17 > 0:19:21A storm like this could bring a tree crashing down on them.
0:19:21 > 0:19:26This is one of these situations when you can easily get caught out.
0:19:36 > 0:19:40And then, just as they reach base camp, a terrible sound is heard.
0:19:40 > 0:19:43LOUD CRASH
0:19:43 > 0:19:46It's a forest tree, knocked over by the storm.
0:19:48 > 0:19:52We just heard this huge crash, and there's a tree falling,
0:19:52 > 0:19:53and a lot of rain tonight,
0:19:53 > 0:19:56and what happens is you get these huge trees,
0:19:56 > 0:19:58that are held up by nothing but vines,
0:19:58 > 0:20:02they've died years ago, and what happens when it rains,
0:20:02 > 0:20:03things just start falling,
0:20:03 > 0:20:05so you've got a huge weight just falling,
0:20:05 > 0:20:07and it fell very close,
0:20:07 > 0:20:11so we're just doing a quick scan round that it didn't fall on the sleeping areas.
0:20:14 > 0:20:20100 tons of tree fell to the ground just yards from the base camp.
0:20:20 > 0:20:25No-one was hurt, but it's a sobering reminder of just how far they are from help.
0:20:32 > 0:20:37Next morning, the result of the night storm is all too plain to see.
0:20:39 > 0:20:43For the river fish, it's a chance to try and reach their spawning grounds.
0:20:49 > 0:20:54For the camp cooks, it's a chance to catch some fresh food for dinner.
0:20:55 > 0:20:58An ingenious device.
0:20:58 > 0:21:01The fish get stuck in the inside bit,
0:21:01 > 0:21:03and they can't get back out again,
0:21:03 > 0:21:06so if I was to put my arm in here, which I won't,
0:21:06 > 0:21:08but if I did, then I would be trapped inside.
0:21:08 > 0:21:10It's absolutely fantastic.
0:21:10 > 0:21:14The break in the weather allows the last of the supplies to be ferried in.
0:21:19 > 0:21:23Well, the helicopter came in unexpectedly,
0:21:23 > 0:21:25and we got covered in muck.
0:21:25 > 0:21:28So, I'm just going for a little swim, now.
0:21:38 > 0:21:41Go and get him, go and get him!
0:21:50 > 0:21:53My hero! Rescued me.
0:21:54 > 0:21:55Thank you.
0:22:00 > 0:22:02Just a few yards away, in the camp,
0:22:02 > 0:22:05there's an air of quiet concentration.
0:22:07 > 0:22:10Steve Backshall and the rest of the mountaineering team
0:22:10 > 0:22:13are making preparations for climbing a remote jungle peak.
0:22:13 > 0:22:16There's a briefing on the use of the radios,
0:22:16 > 0:22:19their only safety line in an emergency.
0:22:19 > 0:22:22So, during the day, you're going to be on channel three,
0:22:22 > 0:22:26and at night time, or late afternoon, we'll put you onto channel one.
0:22:29 > 0:22:32Their destination - Mount Kuli.
0:22:32 > 0:22:35Permanently shrouded in cloud.
0:22:35 > 0:22:38The team will spend a week climbing through the thick mist
0:22:38 > 0:22:42to discover what lies at the top of this mysterious mountain.
0:22:45 > 0:22:48My mother would say to you, don't take any chances.
0:22:48 > 0:22:49Don't do anything silly.
0:22:49 > 0:22:52A spider? Is that a poisonous one?
0:22:52 > 0:22:54It's very poisonous, yeah.
0:22:54 > 0:22:58But just as they are leaving, there's a nasty intruder in camp.
0:22:58 > 0:23:00That is a Scolopendra Centipede,
0:23:00 > 0:23:05which is the nastiest biting creature around here of any kind,
0:23:05 > 0:23:09but I'll let George explain that to you.
0:23:09 > 0:23:10If that was to bite you,
0:23:10 > 0:23:14your hand would expand like a blown up glove, very painful.
0:23:14 > 0:23:15It's very small, actually.
0:23:18 > 0:23:21The climbers start the long walk in to Mount Kuli,
0:23:21 > 0:23:24carrying all their gear and food on their backs.
0:23:28 > 0:23:31They have 25-kilo backpacks on, that's tough going.
0:23:31 > 0:23:33It's going to be hard, really hard work.
0:23:35 > 0:23:38As they trudge through the understorey,
0:23:38 > 0:23:41high above, Justine sits, and waits for her gibbons.
0:23:46 > 0:23:49This is my little platform.
0:23:49 > 0:23:52It's not very big, as you can see.
0:23:52 > 0:23:54It's a long way down.
0:23:54 > 0:23:55I got leeched on the way up,
0:23:55 > 0:23:58that's the problem with being on the ground.
0:23:58 > 0:24:01up here, you don't get any leeches.
0:24:02 > 0:24:03Getting up at 4am is pretty grim,
0:24:03 > 0:24:06and trudging up these muddy slopes before light,
0:24:06 > 0:24:09but it's worth it when you get up here.
0:24:09 > 0:24:15Justine is spending every single daylight hour perched in her tree top.
0:24:16 > 0:24:18It's pretty frustrating,
0:24:18 > 0:24:21because I can actually hear the gibbons,
0:24:21 > 0:24:24but I can't see them, and they're not very far,
0:24:24 > 0:24:28but they're just behind some trees and endless vegetation.
0:24:33 > 0:24:36It's just a bit... It's a bit frustrating, that's all.
0:24:38 > 0:24:42It's even more frustrating for the team of climbers.
0:24:42 > 0:24:45After the heavy rain, the mountain has turned to mud.
0:25:02 > 0:25:09Hopefully, there should be some fabulous new species here.
0:25:09 > 0:25:14Just gonna need some time to get out, and start looking,
0:25:14 > 0:25:17cos at the moment, all you can really focus on
0:25:17 > 0:25:20is putting one foot in front of the other...
0:25:23 > 0:25:27..and just fighting to get some purchase on the steep ground.
0:25:29 > 0:25:32Feeling for every handhold, they inch their way upwards.
0:25:37 > 0:25:40And into the dense layer of cloud.
0:25:51 > 0:25:55In the canyon, patience has paid off for Justine.
0:25:55 > 0:25:59The gibbons have at last come close enough to be filmed.
0:25:59 > 0:26:02GIBBONS CALL
0:26:13 > 0:26:15Suddenly, they all started calling,
0:26:15 > 0:26:20but they started calling right here, almost next to me.
0:26:21 > 0:26:25Incredible that they've come so close.
0:26:25 > 0:26:27I never expected that.
0:26:50 > 0:26:54They can travel through the canopy as fast as birds can fly.
0:26:54 > 0:26:56That would be a great thing to experience,
0:26:56 > 0:27:01and also being able to hang on one arm for about 15 minutes, whilst eating.
0:27:01 > 0:27:03That would be cool, wouldn't it?
0:27:09 > 0:27:15Justine has discovered that there's a healthy population of gibbons in this remote canyon.
0:27:15 > 0:27:19It's a major boost to ensuring its conservation.
0:27:30 > 0:27:34That evening, the team look at Justine's pictures.
0:27:37 > 0:27:41It's been a successful week, with over 20 species captured on camera,
0:27:41 > 0:27:46including the tarsier and the gibbons, and many more recorded.
0:27:46 > 0:27:49A round of applause coming up. Yay!
0:27:49 > 0:27:53Only the clouded leopard has eluded them. So far.
0:27:53 > 0:27:57Kuli team, this is BBC base, over.
0:27:57 > 0:28:00But even as they celebrate, trouble is brewing.
0:28:00 > 0:28:03The climbing team has lost communication with base camp.
0:28:03 > 0:28:05Kuli team, this is BBC Base, over.
0:28:07 > 0:28:11Ever since they disappeared into the clouds on Mount Kuli,
0:28:11 > 0:28:14there's been nothing on the radio but static.
0:28:14 > 0:28:17This is BBC Base. Nothing heard, move to channel two.
0:28:17 > 0:28:23The experienced mountaineers know just how vital the daily radio check is.
0:28:24 > 0:28:26Something must be wrong.
0:28:30 > 0:28:32In the next programme,
0:28:32 > 0:28:36rain keeps on pouring, and problems start mounting up in camp.
0:28:36 > 0:28:38Things are going a bit downhill.
0:28:38 > 0:28:40A few people have got diarrhoea.
0:28:40 > 0:28:42We've run out of petrol,
0:28:42 > 0:28:43which means no electricity,
0:28:43 > 0:28:45and worst of all, river's in flood,
0:28:45 > 0:28:48so getting anywhere is really difficult.
0:28:48 > 0:28:50But despite everything,
0:28:50 > 0:28:52the team makes an amazing discovery.