[00:32.31]This is our planet's hothouse. The jungle.
[00:35.85]The tropical rainforest.
[00:40.54]Forests like these occupy only three percent of the land
[00:44.25]yet they're home to over half of the world's species.
[00:49.64]But how do so many different kinds of plants and animals
[00:53.37]find the space here to live alongside one another?
[01:08.78]On the dark, humid forest floor the jungle appears to be lifeless.
[01:15.62]Often the only signs of life are what you hear.
[01:25.92]A male blue bird of paradise is advertising for a mate.
[01:32.35]It's quite a performance
[01:33.91]but he's not the only bird of paradise here keen to make an impression.
[01:40.18]There are nearly forty different kinds on the island of New Guinea
[01:43.87]each with a display seemingly more bizarre than the rest.
[01:56.48]A riflebird of paradise.
[02:08.85]Like many jungle animals, birds of paradise avoid competing with each other
[02:13.86]and these do so by living in different parts of this jungle covered island.
[02:24.56]The six plumed bird of paradise displays in his special clearing, on the forest floor.
[02:37.62]The magnificent bird of paradise favors the low branches of bushes.
[02:46.45]His female is modestly dressed.
[03:01.17]The male has a good set of lungs
[03:03.77]but he'll have to do more than flutter his eyelids, if he wants to impress her.
[03:15.03]It'll all depend on his performance.
[03:22.38]The females may be dull looking but they're very picky
[03:27.92]and it's time for a really close inspection.
[03:36.83]His right side looks fine... but what about his left?
[03:45.32]Pretty impressive, but is he magnificent enough?
[03:51.57]Oh dear. Her departure says it all.
[03:55.42]Generations of choosy females have driven the evolution
[03:59.45]of these remarkable displays.
[04:02.73]The more extravagant a male is, the more likely he'll be noticed.
[04:31.98]New Guinea lies in a warm tropical belt that girdles our planet around the equator.
[04:38.62]With abundant rainfall and twelve hours of daylight
[04:41.96]three hundred and sixty five days a year, it's here that rainforests flourish.
[04:52.85]Surprisingly only two percent of the sunlight filters down to the forest floor.
[05:00.87]Down here seedlings struggle to grow
[05:05.17]but the gloom is not eternal.
[05:40.28]The death of a forest giant is always saddening
[05:44.40]but it has to happen if the forest is to remain healthy.
[05:50.34]The sudden blaze of sunlight will bring life to the forest floor.
[05:59.24]A single hectare of rainforest may contain as many as 250 species of tree.
[06:05.37]That's nearly ten times the number that grow in Britain
[06:08.77]and the thirst for light triggers a race for a place in the sun.
[06:28.88]There's no time to waste.
[06:30.79]A seed that may have fallen only a few days ago, now bursts through the leaf litter.
[06:50.68]With so many competitors, getting a good start is critical
[06:57.75]but each plant has it's own particular strategy
[07:01.57]for making the most of this rare opportunity.
[07:05.91]The seeds of hardwoods are quick to germinate
[07:08.76]but, like the fabled tortoise, their strategy is to be slow and steady.
[07:18.53]Vines and other climbers put all their energy into rapid vertical growth, rather than girth
[07:25.68]though they'll need to be well supported.
[07:34.33]The climbers' strategy looks chaotic but there's method in their madness.
[07:38.81]Their growing tips circle like lassoes, searching out anchors for their spindly stems.
[07:51.74]They put coils in their tendrils
[07:53.96]so that if their support moves, they will stretch and not snap.
[08:00.78]But the frontrunners at this stage, the first to fill the clearing,
[08:04.73]are pioneers like the macarangas.
[08:08.76]Their immense leaves capture huge amounts of sunlight, so fueling their growth.
[08:20.79]As a result the macarangas grow a remarkable eight meters a year
[08:25.21]surging ahead of almost all their rivals.
[08:40.93]In the race for the top spot hundreds will start
[08:44.67]yet few will ever reach the finishing line, their growth cut short by the diminishing light.
[08:53.65]In less than four years, the gap will have gone
[08:57.72]but that's not the end of the race.
[09:09.35]The ultimate winners are the tortoises, the slow and steady hardwoods.
[09:17.24]When the short lived pioneers have fallen
[09:20.54]it's the hardwoods that take their place, and a fifty meter giant, like this one,
[09:26.20]may keep it's place in the sun for another two hundred years.
[10:06.94]At the top, is the canopy, the engine room of the jungle.
[10:11.36]It's up here that most of the animal life in the rainforest can be found
[10:17.67]But despite the apparent abundance of vegetable food, gathering it is seldom easy.
[10:37.94]With no real seasons
[10:40.20]each tree flowers or fruits at a different time of the year
[10:44.32]which means that food is very widely spaced.
[10:53.27]Monkeys, like these tamarinds, must search the canopy for all kinds of food
[10:58.61]if they're to survive.
[11:03.09]but across the world's rainforests there's one type of fruiting tree
[11:08.05]that always delivers: the fig.
[11:20.92]Wherever they grow, figs are a magnet for the great diversity of animals.
[11:29.06]In the Amazon, the first to appear are the spider monkeys.
[11:34.97]These large primates are big fig eaters
[11:38.21]But they won't have the tree to themselves for long. Others will want a share.
[11:44.52]like the diminutive emperor tamarinds.
[11:50.97]The tamarinds love figs too, but being petite means they're easily scared off.
[12:06.79]Squirrel monkeys are also small but they have strength in numbers.
[12:14.03]Their timeshare on the tree may be short, so their tactics are more smash and grab.
[12:28.55]Capuchin monkeys are the bully boys in these forests
[12:32.05]and they want the ripe figs for themselves.
[12:52.12]Figs are one of the few trees that fruit the year round
[12:56.60]so when other food is scarce, these fruits are always available somewhere or other.
[13:06.86]Even for leaf eaters, like howler monkeys the ripe figs are just too good to miss.
[13:18.43]And howlers are too big for the capuchins to chase off.
[13:26.77]Figs are so popular, that as many as 44 different kinds of bird and monkey
[13:32.19]have been seen working a shift system on a single tree.
[13:45.26]Because fruiting trees are so valuable, many monkeys are territorial
[13:51.08]And if you live in the treetops
[13:52.95]there's perhaps no better way of staking your claim to a territory, than this.
[14:03.97]The calls of the siamang gibbons begin as a duet
[14:07.82]between the dominant male and female.
[14:22.49]The rest of their families soon join in, and it results in a frenzy of activity.
[14:36.72]The calls can carry over a mile, and their message is clear.
[14:46.74]They tell any neighboring siamangs this is our territory. Keep out.
[15:01.81]Up here the calls of siamang gibbons seem to dominate the airwaves
[15:07.20]but with the jungle's incredible diversity
[15:09.97]there are countless others trying to be heard too.
[15:19.25]Every layer seems to beat to a different tune.
[15:40.32]In the early morning the forest's chorus is particularly rich.
[15:45.03]Sounds travel further in the cooler air
[15:52.27]But few calls can penetrate as far through the dense vegetation as this one
[15:58.50]the deep bass solo of a male orangutan.
[16:17.82]In the middle of the day little stirs in the jungle
[16:21.20]and the hot dense air muffles the sound.
[16:28.10]As the afternoon wears on, a different set of players begin to warm up.
[16:35.62]Insects work in harmony, timing their calls to fall between the notes of others.
[16:49.19]Many singers stick to precise schedules
[16:52.33]and right on cue the six o'clock cicadae.
[17:08.05]Night brings out a whole new orchestra.
[17:35.45]The cacophony of competing calls seems deafening to us
[17:40.03]but frogs ears are tuned to hear only the calls of their own kind.
[17:52.61]The songs of courtship echo from all around.
[18:09.20]Male gliding leaf frogs leap from the treetops.
[18:47.99]To slow their descent, they use their huge webbed feet as parachutes.
[18:58.68]These large tree frogs spend most of their lives in the high canopy
[19:03.56]and only come down when it's time to breed.
[19:12.44]Once settled, they begin to serenade their unseen females.
[19:28.81]Now it's time for the females to make their move.
[19:37.21]There's no shortage of suitors, but this female has already made her choice.
[19:42.14]She's heading towards the loudest call, because loud calls come from big frogs
[19:48.35]and big is best, but to reach him she must run the gauntlet of a gang of smaller suitors.
[19:56.25]Their only chance of mating is to make a sneaky interception.
[20:07.85]But with more females arriving all the time, it's not over until the fat frog stops singing.
[20:20.72]Feet, so vital for gliding, are now put to other uses.
[20:31.00]Two's company, three's inconvenient
[20:35.50]but in any case, all male frogs are equipped with dry thumbs
[20:40.14]which enable them to get a vice like grip on their moist partners.
[20:46.09]It's a case of first come first served.
[20:57.77]Living in such a humid environment, means jungle frogs are less tied to puddles and pools
[21:04.45]and these even lay their eggs out of water.
[21:17.32]There's little chance of them drying out
[21:20.11]and up here they're safer from predators.
[21:30.83]Surprisingly, it doesn't rain every day in the rainforest
[21:36.11]but more still falls here than anywhere else on Earth.
[21:40.12]On average, over two meters a year.
[21:52.90]A single tree can suck up hundreds of tons of water each year
[22:00.97]But the trees can't use all this water
[22:03.41]so, much of it returns to the air as vapor, forming mist and clouds.
[22:14.85]In the Amazon, the largest unbroken stretch of rainforest in the world,
[22:19.74]half of all the rainwater that falls, comes from clouds produced by the trees themselves.
[22:57.72]With so much rain, it's not surprising that many of the worlds largest rivers
[23:03.32]are found in rainforests.
[23:20.44]Inside the forest, the high humidity
[23:23.60]creates the perfect conditions for a strange world, where life is built on decay.
[23:42.72]Amoeba like slime molds cruise the surface, feeding on bacteria and rotting vegetation.
[24:06.45]Fungi also flourish on decay.
[24:11.79]These are the fruiting bodies of the fungi, the only visible sign
[24:16.80]of a vast underground network of fungal filaments.
[24:52.08]In temperate forests, the buildup of leaf litter creates rich stores of nutrients.
[24:57.80]That however, doesn't happen here.
[25:04.23]Nutrients that reach the soil are leeched out by the rain
[25:08.28]but fungi are connected to tree roots by their underground filaments
[25:12.78]and by quickly consuming the dead
[25:14.90]they help to recycle crucial minerals straight back into the trees.
[25:26.73]And this recycling happens faster here, than anywhere else on the planet.
[25:51.87]There are thought to be nearly a million different types of fungi in the tropics.
[25:57.10]The vast majority still unknown to science
[26:07.34]But one thing's for certain
[26:09.83]without fungi, rainforests could not exist.
[26:25.26]Nothing goes to waste in the rainforest.
[26:28.37]The fungi become food for others like these beetle larvae.
[26:37.17]Finding the fungus isn't a problem for the grubs
[26:40.22]since their caring parents actually show them the way.
[26:57.40]Incredibly, 80% of all insects live in jungles
[27:02.84]fewer more successful than the ants. There can be 8 million individuals in a single hectare.
[27:10.70]but jungle ants don't have it all their own way.
[27:21.14]These bullet ants are showing some worrying symptoms.
[27:26.76]Spores from a parasitic fungus called cordyceps
[27:30.50]have infiltrated their bodies and their minds.
[27:40.79]It's infected brain directs this ant upwards
[27:46.91]then, utterly disorientated, it grips a stem with it's mandibles.
[27:52.49]Those afflicted, that are discovered by the workers
[27:55.55]are quickly taken away and dumped far away from the colony.
[28:01.35]It seems extreme, but this is the reason why.
[28:07.50]Like something out of science fiction
[28:10.37]the fruiting body of the cordyceps erupts from the ant's head.
[28:29.77]It can take three weeks to grow
[28:32.52]and when finished, the deadly spores will burst from it's tip
[28:37.20]then, any ant in the vicinity will be in serious risk of death.
[28:44.65]The fungus is so virulent, it can wipe out whole colonies of ants
[28:49.52]and it's not just ants that fall victim to this killer.
[28:55.36]There are literally thousands of different types of cordyceps fungi
[29:00.08]and remarkably, each specializes on just one species
[29:40.23]but these attacks do have a positive effect on the jungle's diversity.
[29:45.28]Since parasites like these stop any one group of animal getting the upper hand.
[29:52.08]The more numerous a species becomes, the more likely it'll be attacked by it's nemesis
[29:57.51]a cordyceps fungus.
[30:22.88]With so much competition, jungles have become the home of the specialist.
[30:28.82]Now this animal, in the island of Borneo, is one of the most unusual.
[30:34.59]It's a colugo, or flying lemur, though this is something of a misnomer
[30:39.60]as it doesn't actually fly and it certainly isn't a lemur
[30:43.69]in fact nobody's quite sure who it's closest relative is.
[31:07.34]The colugo depends on a diet of young leaves
[31:11.27]and to find enough of them, it must move from tree to tree.
[31:17.26]The leaves are not very nutritious, but then, getting around doesn't use much energy.
[31:29.23]In a single night, a colugo might have to travel as far as two miles
[31:34.01]but that task is made easier by it's superior gliding skills.
[32:10.19]The secret of success in the competitive jungle is specializing
[32:14.81]and this has led to the evolution of some very intimate relationships
[32:19.12]between plants and animals.
[32:23.28]These are pitcher plants also from Borneo.
[32:32.48]Adapted to living in very low nutrient soils
[32:36.45]the pitcher plant gets most of it's nourishment from insects lured to nectar glands
[32:41.76]on the underside of the lids.
[32:45.55]Once onboard, the waxy sides of the pitcher ensure there's little chance of escape.
[32:54.83]Most slip to a watery grave.
[33:05.66]At the bottom of the pitcher glands secrete enzymes
[33:09.94]which help to digest the corpses, so feeding the plant.
[33:15.57]But not all visitors have a fatal attraction to the pitchers.
[33:20.75]The red crab spider spends it's entire life in the pitchers, hanging on with threads of silk.
[33:36.77]Instead of building a web, it relies on the water filled pitcher to trap it's food.
[33:45.28]When an ant falls in, the spider simply waits for it to drown
[33:50.08]and then abseils down for a spot of fishing.
[34:00.87]Alive, this ant would be far too dangerous for the spider to tackle
[34:05.15]so, using the pitchers as traps, means it can get bigger meals
[34:12.76]and the spider doesn't rob the pitcher of everything.
[34:15.92]The digested remains of it's booty will end up in the water
[34:19.77]providing instant food for the plant.
[34:27.09]Other food, like mosquito larvae, seems to be out of reach
[34:31.61]but the spider has another sup rising trick.
[34:34.93]By taking it's own air supply trapped in a bubble
[34:38.17]the crab spider can actually dive to the very bottom of the pitcher.
[34:46.15]Once the prey is captured, the spider hauls itself back up it's silken safety line.
[34:59.89]The pitcher is a one stop shop for this spider, but it's not alone.
[35:05.75]In the jungle there's competition for everything, even a small water filled pitcher plant.
[35:27.05]Such specialists create the jungle's remarkable diversity
[35:32.14]but finding enough food to survive is so challenging
[35:35.40]that most animals living here tend to be small
[35:38.69]though there are exceptions.
[35:48.53]This is the Congo in Africa.
[35:52.13]It's a vast wilderness and the least explored of all jungles.
[35:59.87]From up here the forest looks similar to the ones that grow in the Amazon or Southeast Asia.
[36:06.22]but down below there are some unexpected sights.
[36:27.66]Crisscrossing this forest, are countless miles of highways
[36:32.71]and they were made by something big.
[36:45.10]Forest elephants roam great distances in their search for food
[36:50.30]but to survive, they must emerge from the gloom of the forest.
[36:56.77]And clearings like this one, are a magnet for elephants from far and wide.
[37:56.70]These elephants live in much smaller groups than their savanna cousins.
[38:02.59]This might be the first time that one group will have seen another for a month.
[38:17.41]For the adult males it's a welcome break in an otherwise largely solitary existence
[38:32.09]and they're not the only animals attracted to the clearing.
[38:38.46]Forest buffaloes and red river hogs are also regular visitors
[38:44.30]as are bongos, which are very difficult to see outside these clearings.
[38:50.08]All these large forest animals have come here to collect an essential element of their diet
[38:56.03]that lies buried beneath the mud.
[39:03.42]And the elephant's trunk is the perfect tool for reaching it.
[39:21.88]To get what they seek
[39:23.29]the prospecting elephants must first blow away the covering layer of silt.
[39:49.86]Satisfaction at last.
[39:57.45]They're collecting a particular kind of clay
[40:00.48]that contains vital minerals scarce in their natural diet.
[40:04.90]It may be mud, but there's just nothing quite like it for enriching the blood.
[40:11.90]The clay also helps to absorb the toxins found in many leaves that the elephants eat.
[40:23.73]There are other benefits to coming here.
[40:27.40]These clearings are the only places where the forest elephants
[40:30.53]can get together in such numbers.
[40:33.50]When they return to the forest, they will have to go their separate ways, once more.
[40:59.24]If large animals are rare in jungles
[41:02.52]then groups of large animals actually living together, are even rarer.
[41:26.03]This posse of hunters is not only formidable, it's also very large.
[41:51.30]In their search for food chimpanzees move effortlessly
[41:55.49]between the forest floor and the canopy.
[41:58.60]They're one of the few jungle animals able to do so.
[42:16.64]Figs are a vital part of a chimpanzee's diet
[42:20.92]and some just can't seem to get enough of them.
[42:34.05]But there's something special about this stretch of forest in Uganda.
[42:38.28]Fruit is actually abundant
[42:46.49]and a lot of food supports lots of chimps.
[43:07.01]At a hundred and fifty strong, this community of chimps
[43:10.92]is the biggest yet found in Africa.
[43:13.79]Their numbers are so large, that they need a big territory, lots of fig trees
[43:19.16]and they're willing to fight for it.
[43:30.52]These calls announce the start of a raid into land controlled by their neighbors.
[43:42.58]As they leave their core zone, the patrol goes silent, occasionally stopping to listen.
[43:53.55]Signs of the enemy are detected and examined closely.
[44:12.65]The chimp militia are now at the very edge of their territory.
[44:18.35]All need to be on maximum alert.
[44:29.89]Then it's wait and listen.
[44:53.48]An unfamiliar chimp call raises the tension.
[44:57.56]It's an uncertain time. The size of the rival group is as yet unknown.
[45:07.12]Not far away the neighbors are feeding in a fig tree
[45:11.01]oblivious to the approaching dangers.
[45:15.49]The patrol moves off with a sense of purpose.
[45:19.13]They must remain silent until they close in on their rivals.
[45:34.91]The attack is on.
[45:39.13]To intimidate their opponents, the aggressors scream and drum on buttress roots.
[46:04.33]Several males corner an enemy female.
[46:07.42]It's a ferocious attack, and she's lucky to escape with her life.
[46:28.80]Others are not so fortunate.
[46:37.55]The battle won, a grizzly scene unfolds.
[46:42.54]An enemy youngster has been caught and killed.
[46:45.90]The carcass is shared between members of the group, and eaten.
[46:54.41]Killing a competitor makes sense if you want to protect your food supply
[47:02.51]but exactly why they cannibalize the dead chimp, is not fully understood.
[47:08.54]It may simply be a chance for some extra protein.
[47:24.34]Teamwork has brought this group of chimps great success
[47:28.53]but they'll soon reach the limits of their power.
[47:33.07]The competition for resources ensures that no one species dominates the jungle.
[47:46.16]The rainforest's great diversity has come at a cost.
[47:50.31]It has made them the most finely balanced ecosystems in the world
[47:54.49]only too easily upset and destroyed by that other great ape
[47:59.55]the chimpanzee's closest relative
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