0:00:35 > 0:00:40Imagine a world where temperatures rise to 120 degrees Fahrenheit.
0:00:45 > 0:00:49Where there's no escape from sun, wind and dust.
0:00:55 > 0:00:59Imagine a world with almost no food or water.
0:01:08 > 0:01:11These are the conditions in
0:01:11 > 0:01:14one third of the lands of our planet.
0:01:17 > 0:01:22To live here demands the most extraordinary survival strategies.
0:01:45 > 0:01:49This is the oldest desert in the world.
0:01:49 > 0:01:52The Namib in south-west Africa.
0:01:53 > 0:01:57It's been dry for 55 million years.
0:02:02 > 0:02:06Life here for a hunter is as hard as it gets.
0:02:17 > 0:02:19A pride of lions.
0:02:19 > 0:02:23One of the very few that endures this desert's scorching temperatures
0:02:23 > 0:02:25and lack of water.
0:02:42 > 0:02:46Hunting here presents special problems.
0:02:52 > 0:02:57A herd of oryx, the only prey within 20 miles.
0:03:01 > 0:03:05Out here, there is no cover for an ambush.
0:03:05 > 0:03:08It'll have to be a straight chase.
0:03:45 > 0:03:47They have failed
0:03:47 > 0:03:51and each failed hunt brings the lions closer to starvation.
0:04:03 > 0:04:05To find enough to eat,
0:04:05 > 0:04:10the pride continually searches an area the size of Switzerland.
0:04:19 > 0:04:26Three days and 100 miles later, and still no kill.
0:04:28 > 0:04:30These are desperate times.
0:04:30 > 0:04:32BIRDS CAW
0:04:34 > 0:04:37A dry riverbed on the edge of their territory.
0:04:40 > 0:04:43The only animals here are giraffe,
0:04:43 > 0:04:48but these one-tonne giants could kill a lion with a single kick.
0:05:01 > 0:05:05Lions seldom tackle such formidable prey...
0:05:08 > 0:05:13..but this pride can't go on much longer without food.
0:05:40 > 0:05:44The whole pride must work together as a team if they're to succeed.
0:06:13 > 0:06:15Two lionesses lead the chase.
0:06:15 > 0:06:18Others race to cut off possible escape routes.
0:06:35 > 0:06:40The giraffe has the speed and stamina to outrun the pride...
0:06:41 > 0:06:44..but it's being chased into a trap.
0:06:46 > 0:06:49Up ahead, the lead female waits.
0:07:00 > 0:07:02It's now up to her.
0:07:21 > 0:07:23Most lion hunts end in failure.
0:07:25 > 0:07:30But no lions fail more often than those that live in the desert.
0:07:34 > 0:07:38Once again, the pride must continue their search.
0:07:45 > 0:07:46THUNDER RUMBLES
0:08:02 > 0:08:06It does, sometimes, rain in the desert.
0:08:09 > 0:08:15Here, in the American West, storms can strike with devastating force.
0:08:20 > 0:08:22After ten months of drought,
0:08:22 > 0:08:27millions of tonnes of water are dumped on the land in under an hour.
0:09:16 > 0:09:18Over millions of years,
0:09:18 > 0:09:21sand and gravel carried by the rampaging floods
0:09:21 > 0:09:24have carved channels through the solid rock.
0:09:29 > 0:09:33Slot canyons, 150 feet deep.
0:10:05 > 0:10:08In some places, these canyons have widened
0:10:08 > 0:10:12until the land between them is sculpted into tablelands
0:10:12 > 0:10:15and isolated pinnacles,
0:10:15 > 0:10:19some of the most dramatic landscapes on the planet.
0:10:35 > 0:10:37The rain may be long gone...
0:10:39 > 0:10:41..but there is water here...
0:10:43 > 0:10:47..locked away within the tissues of specialist desert plants.
0:10:49 > 0:10:53Cacti are unique to American deserts.
0:10:55 > 0:10:57They all hoard water,
0:10:57 > 0:10:59storing it in swollen stems
0:10:59 > 0:11:03and protecting it behind a barricade of spines.
0:11:07 > 0:11:11They're so successful that they dominate these deserts.
0:11:13 > 0:11:16But this forest of spikes can cause
0:11:16 > 0:11:18problems for the animals that live here.
0:11:26 > 0:11:28A Harris hawk.
0:11:31 > 0:11:35It has developed special techniques for hunting amongst the cacti.
0:11:41 > 0:11:43Ground squirrels.
0:11:43 > 0:11:44Prey.
0:11:53 > 0:11:56At the first sign of danger they bolt for the safety of the thorns.
0:12:06 > 0:12:09But the hawks have a tactic to flush them out.
0:12:12 > 0:12:16These are the only birds of prey that hunt in packs.
0:12:19 > 0:12:23Flying in formation, they try to drive their quarry into the open.
0:12:34 > 0:12:37But this squirrel is staying put.
0:12:43 > 0:12:46So now the hawks continue the hunt...
0:12:47 > 0:12:48..on foot.
0:12:56 > 0:12:59They're closing in from all sides.
0:13:20 > 0:13:24Soon, all escape routes are cut off.
0:13:28 > 0:13:30The squirrel is trapped.
0:13:41 > 0:13:44The spines that cover almost every plant in this desert
0:13:44 > 0:13:48can provide protection and shelter for many animals.
0:13:56 > 0:14:01So, why should these spikes be hung with corpses?
0:14:07 > 0:14:09What kind of creature could be responsible
0:14:09 > 0:14:12for creating such a gruesome scene?
0:14:21 > 0:14:25There's a mysterious killer at work in this desert.
0:14:32 > 0:14:34It's a butcherbird.
0:14:36 > 0:14:41This little songbird uses the spines as a butcher uses his hook -
0:14:41 > 0:14:45to hold its prey as it dismembers it.
0:14:49 > 0:14:50CHICKS SQUAWK
0:14:55 > 0:14:59And with chicks to feed, he also uses the spines as a larder.
0:15:05 > 0:15:07He's been stocking it for weeks.
0:15:10 > 0:15:14Hanging his prey out of the reach of scavengers on the ground
0:15:14 > 0:15:18ensures that his newly hatched young will never go hungry.
0:15:20 > 0:15:24An ingenious solution to making the good times last in the desert...
0:15:28 > 0:15:30..if a little macabre.
0:15:30 > 0:15:31CHICKS SQUAWK
0:15:39 > 0:15:41Some deserts are so arid,
0:15:41 > 0:15:44they appear totally devoid of all vegetation.
0:15:47 > 0:15:52Yet even these landscapes can be transformed in a matter of days.
0:16:03 > 0:16:07The deserts of Peru are amongst the driest in the world,
0:16:07 > 0:16:11but just add a little water and plants that have lain dormant
0:16:11 > 0:16:14for months will burst into life.
0:16:31 > 0:16:33And when a desert suddenly turns green,
0:16:33 > 0:16:39even the most seemingly desolate can become a land of opportunity.
0:16:51 > 0:16:55No creature exploits the greening of a desert more quickly
0:16:55 > 0:16:57or more dramatically than a locust.
0:17:07 > 0:17:09Madagascar's arid south-west
0:17:09 > 0:17:12has received its highest rainfall in years.
0:17:18 > 0:17:21Now, an army is on the march,
0:17:21 > 0:17:24attracted by the smell of newly sprouting grass.
0:17:36 > 0:17:38Locusts are normally solitary creatures,
0:17:38 > 0:17:42but when food becomes suddenly plentiful they come together
0:17:42 > 0:17:46into an unstoppable force that devours everything in its path.
0:18:05 > 0:18:09But this devastation is about to get a lot worse.
0:18:21 > 0:18:26The locusts now transform into winged adults,
0:18:26 > 0:18:28and with conditions as good as this,
0:18:28 > 0:18:31they do so three times faster than normal.
0:18:33 > 0:18:37Now they are at their most voracious...
0:18:37 > 0:18:40and with wings, they can take to the skies.
0:19:05 > 0:19:09Once airborne, the locusts can travel over 60 miles a day
0:19:09 > 0:19:12in their search for new feeding grounds.
0:19:26 > 0:19:31A super swarm of this scale may only appear once in a decade.
0:19:32 > 0:19:35This one extends over 200 square miles
0:19:35 > 0:19:38and contains several billion individuals.
0:19:40 > 0:19:44Between them, they will devour 40,000 tonnes of food in a day.
0:20:20 > 0:20:24Nothing can strip a land of its vegetation with such speed
0:20:24 > 0:20:27and thoroughness as a plague of locusts.
0:20:30 > 0:20:35When the food eventually runs out, the whole army will die...
0:20:35 > 0:20:38but not before it's devastated the land.
0:20:53 > 0:20:55With no plants to bind them,
0:20:55 > 0:20:59thin soils soon turn to dust and blow away.
0:21:06 > 0:21:10Now, these barren lands are left to the mercy of the elements.
0:21:27 > 0:21:32Scorched by the sun and scoured by windblown sand,
0:21:32 > 0:21:37desert rock is shaped into strange, otherworldly landscapes.
0:21:44 > 0:21:48These rocky deserts may have a beguiling beauty,
0:21:48 > 0:21:52but when they become this barren, very little life can endure.
0:21:59 > 0:22:03For many animals, the only way to survive the most hostile times
0:22:03 > 0:22:04is to keep moving.
0:22:12 > 0:22:16In the Kalahari, brief rains have given way to the dry season.
0:22:17 > 0:22:20Food and water are becoming increasingly scarce.
0:22:22 > 0:22:25For these zebra, it's time to leave.
0:22:38 > 0:22:39They're setting off on
0:22:39 > 0:22:44the longest overland migration made by any mammal in Africa,
0:22:44 > 0:22:47marching towards the scent of distant rains.
0:22:51 > 0:22:53As drought intensifies,
0:22:53 > 0:22:57desert-living elephants must also undertake long journeys
0:22:57 > 0:22:59in search of water.
0:23:20 > 0:23:22The older females can remember where,
0:23:22 > 0:23:27even in times of extreme drought, there may still be water
0:23:27 > 0:23:31and sometimes lead the herd to a water hole they may not have visited
0:23:31 > 0:23:32for decades.
0:24:02 > 0:24:06These zebra are almost at the end of their journey.
0:24:13 > 0:24:15This is what they've been heading for...
0:24:19 > 0:24:21..a rare water hole.
0:24:31 > 0:24:35In deserts, most water holes are short lived.
0:24:35 > 0:24:36They appear after rains,
0:24:36 > 0:24:39but then vanish almost as quickly as they came.
0:24:46 > 0:24:49Animals have come here from many miles around.
0:24:54 > 0:24:59Yet this can be a dangerous place in which to linger.
0:25:07 > 0:25:1060 miles away, in the heart of the desert,
0:25:10 > 0:25:12sandgrouse chicks are hatching.
0:25:13 > 0:25:15It's safer for them to be here.
0:25:20 > 0:25:24But being so distant from water is a gamble.
0:25:27 > 0:25:30With only their mother to shield them from the sun,
0:25:30 > 0:25:34if they get nothing to drink, they will be dead within hours.
0:25:42 > 0:25:45Their only hope is their father.
0:25:48 > 0:25:52Every morning he makes the 120-mile round trip
0:25:52 > 0:25:54to get water for the family.
0:25:58 > 0:26:01Grouse from all over the desert visit this oasis,
0:26:01 > 0:26:05arriving together in large flocks,
0:26:05 > 0:26:06and that is important.
0:26:10 > 0:26:12There's safety in numbers.
0:26:27 > 0:26:29The male snatches a drink,
0:26:29 > 0:26:33but he also needs to collect water for his chicks.
0:26:34 > 0:26:36Using specially adapted breast feathers,
0:26:36 > 0:26:39he can soak up water like a sponge.
0:26:40 > 0:26:43But it takes time, and he is in danger.
0:26:51 > 0:26:53Goshawk.
0:27:09 > 0:27:11Sandgrouse here are their main prey.
0:27:17 > 0:27:22Again and again, the male sandgrouse risk their lives
0:27:22 > 0:27:24in order to collect water for their chicks.
0:27:45 > 0:27:49This is why sandgrouse nest so far from water holes.
0:28:13 > 0:28:16At last, he's soaked up as much as he can.
0:28:18 > 0:28:21Carrying a quarter of his body weight in water,
0:28:21 > 0:28:24he can now set off on the long journey home.
0:28:51 > 0:28:54He's back, and just in time.
0:28:55 > 0:28:58He can give the chicks their first ever drink.
0:29:06 > 0:29:10But he will have to undertake this perilous journey every day
0:29:10 > 0:29:14for the next two months until his chicks can finally make the flight
0:29:14 > 0:29:16to the water hole for themselves.
0:29:29 > 0:29:33It's July in the deserts of Nevada in the western United States.
0:29:35 > 0:29:37The hottest time of the year.
0:29:51 > 0:29:54Bands of wild horses, mustang,
0:29:54 > 0:29:58are converging on one of the last remaining water holes for miles.
0:30:03 > 0:30:07Now, water not only offers them the chance to drink,
0:30:07 > 0:30:09it can also bring power.
0:30:13 > 0:30:16If a stallion can control access to water,
0:30:16 > 0:30:19he will have secured mating rights to the entire herd.
0:30:21 > 0:30:24So stallions try to dominate these pools,
0:30:24 > 0:30:26fighting off rivals who venture too close.
0:30:39 > 0:30:41A stranger.
0:30:43 > 0:30:45He's travelled ten miles to be here
0:30:45 > 0:30:48because the pools where he's come from have already dried up.
0:30:52 > 0:30:54With him come his females.
0:30:57 > 0:31:00If he can't provide them with water, they will leave him
0:31:00 > 0:31:04for the white stallion who already dominates this pool.
0:31:14 > 0:31:17So, he will have to fight.
0:32:17 > 0:32:18There is everything to lose.
0:32:20 > 0:32:23A broken leg or a shattered jaw
0:32:23 > 0:32:25would mean a slow and painful death.
0:32:46 > 0:32:49A missed kick, and it's all over.
0:32:52 > 0:32:56The new arrival has won...
0:32:56 > 0:33:00and his prize is more than just the chance to drink.
0:33:00 > 0:33:03He has provided for his herd, and in the process,
0:33:03 > 0:33:06stolen his rival's females.
0:33:07 > 0:33:10The white stallion's rule is over.
0:33:18 > 0:33:22Desert life is not only shaped by the scarcity of water,
0:33:22 > 0:33:27but also by the relentless power of the sun.
0:33:33 > 0:33:36The highest temperatures on Earth
0:33:36 > 0:33:38have all been recorded in its deserts.
0:33:50 > 0:33:53Changes in the climate mean temperatures here
0:33:53 > 0:33:56are rising more than the global average and,
0:33:56 > 0:33:59as deserts heat up, they are also expanding.
0:34:02 > 0:34:06Every year, a further 50,000 square miles of grass and farmland
0:34:06 > 0:34:10are turning into barren stretches of dust and rock.
0:34:16 > 0:34:21In the heat of the day, surface temperatures can reach 160 degrees,
0:34:21 > 0:34:24far too hot to handle for most.
0:34:27 > 0:34:30But not for this shovel-snouted lizard.
0:34:35 > 0:34:37Raising its feet off the ground in turn...
0:34:40 > 0:34:43..enables each to briefly cool.
0:34:49 > 0:34:52But even this dancing desert specialist
0:34:52 > 0:34:54can't stand the heat for long.
0:35:03 > 0:35:05One option is to find shade.
0:35:10 > 0:35:15Dune grass, the only vegetation here, provides virtually none,
0:35:15 > 0:35:18but just an inch beneath the surface of the sand,
0:35:18 > 0:35:20it is several degrees cooler.
0:35:28 > 0:35:33Avoiding the extreme heat imposes a rhythm on desert life.
0:35:36 > 0:35:39And many animals here choose the simplest option of all...
0:35:42 > 0:35:44..staying hidden all day,
0:35:44 > 0:35:47and only venturing out in the cool of the night.
0:35:56 > 0:36:01As darkness falls, animals appear from seemingly nowhere.
0:36:08 > 0:36:11And, among them, inevitably,
0:36:11 > 0:36:12are hunters.
0:36:28 > 0:36:31One of the most voracious nocturnal predators
0:36:31 > 0:36:34is also one of the hardest to see.
0:36:37 > 0:36:41This mysterious creature hardly ever appears on the surface of the dunes.
0:36:48 > 0:36:52But there are signs on the sand that can give it away.
0:37:06 > 0:37:09It lives only here, where the sand grains are so perfectly dry
0:37:09 > 0:37:13and polished, that they flow almost like water.
0:37:16 > 0:37:18It's no bigger than a ping-pong ball.
0:37:23 > 0:37:25A golden mole.
0:37:26 > 0:37:28It's totally blind,
0:37:28 > 0:37:31but there's nothing to see underground anyway.
0:37:37 > 0:37:40Instead, it has superb hearing.
0:37:42 > 0:37:45Its entire head acts as an amplifier
0:37:45 > 0:37:49that picks up vibrations through the sand, so, to locate prey
0:37:49 > 0:37:53on the surface of the dune, it has, paradoxically,
0:37:53 > 0:37:55to thrust its face into the dune.
0:38:04 > 0:38:06Termites.
0:38:06 > 0:38:08Not easy to catch when you're blind.
0:38:12 > 0:38:15Far better to go into stealth mode.
0:38:17 > 0:38:21Once below the sand, it can detect the slightest movement...
0:38:25 > 0:38:28..allowing it to strike with pinpoint accuracy.
0:38:37 > 0:38:40Well, most of the time.
0:38:52 > 0:38:55They can travel two thirds of a mile a night in search of its dinner...
0:38:59 > 0:39:02..and right now, it has just detected its main course.
0:39:04 > 0:39:08Little wonder it's sometimes called "the shark of the dunes".
0:39:17 > 0:39:21Food can be so scarce in the desert that, even at night,
0:39:21 > 0:39:25animals can't afford to be choosy about what they eat.
0:39:31 > 0:39:33Israel's Negev desert.
0:39:43 > 0:39:47Otonycteris, the desert long-eared bat, is on the hunt.
0:39:51 > 0:39:56Most bats catch flying insects on the wing, but there are so few
0:39:56 > 0:40:00of these in the desert that this bat must do things differently.
0:40:04 > 0:40:06It has to hunt on the ground.
0:40:13 > 0:40:17But what really sets it apart is what it's hunting...
0:40:25 > 0:40:27..a deathstalker scorpion.
0:40:28 > 0:40:32The venom of this species is potent enough to kill a human.
0:40:34 > 0:40:39Tackling it seems madness for a bat weighing just half an ounce.
0:40:43 > 0:40:48In the pitch-black, both predator and prey are effectively blind,
0:40:48 > 0:40:51but the scorpion has one advantage -
0:40:51 > 0:40:55he can sense the approach of the bat through vibrations in the sand.
0:40:59 > 0:41:03Otonycteris must rely entirely on its hearing.
0:41:04 > 0:41:07If the scorpion doesn't move, it won't know it's there.
0:41:22 > 0:41:23The battle is on.
0:41:27 > 0:41:30Armed with crushing pincers and a sting loaded with venom,
0:41:30 > 0:41:33this scorpion is a dangerous opponent.
0:41:46 > 0:41:48A direct strike on the head.
0:41:51 > 0:41:52Is it all over?
0:41:56 > 0:41:58Not for this bat.
0:42:14 > 0:42:18Otonycteris clearly has some immunity to the venom,
0:42:18 > 0:42:21but repeated stings must still be extraordinarily painful.
0:42:30 > 0:42:32And if the bat is not to go hungry,
0:42:32 > 0:42:35it must catch another three scorpions before sunrise.
0:43:03 > 0:43:07Desert animals have developed remarkable strategies
0:43:07 > 0:43:10to make the most of the rare opportunities that come their way.
0:43:13 > 0:43:16Although some deserts may not see rain for several years,
0:43:16 > 0:43:20most will hold a little water in one form or another.
0:43:21 > 0:43:24The trick is simply knowing how to reach it.
0:43:33 > 0:43:38Dawn in the dunes of the Namib, and something magical is happening.
0:43:57 > 0:44:01Moist air lying over the neighbouring Atlantic is cooled
0:44:01 > 0:44:06and blown inland, forming fog banks that shroud the desert in mist.
0:44:14 > 0:44:18This precious moisture lies tantalisingly out of reach
0:44:18 > 0:44:23at the top of the dunes, and it won't last long.
0:44:23 > 0:44:27It'll be burnt off by the sun just hours after it rises.
0:44:42 > 0:44:45Darkling beetles race to the top of the dunes
0:44:45 > 0:44:48to reach the fog before it vanishes.
0:44:57 > 0:45:02Some of the Namib's dunes are 1,000 feet high,
0:45:02 > 0:45:03the tallest in the world.
0:45:05 > 0:45:08For a beetle no larger than a thumbnail, this is the equivalent
0:45:08 > 0:45:12of us climbing a dune twice the height of Everest.
0:45:16 > 0:45:20But even more impressive is what it does next.
0:45:25 > 0:45:28Standing perfectly still, facing into the wind,
0:45:28 > 0:45:31the beetle does a headstand.
0:45:34 > 0:45:37Fog begins to condense on its body.
0:45:40 > 0:45:44Microscopic bumps on its wing cases direct the water
0:45:44 > 0:45:46to grooves that channel it towards the mouth.
0:45:52 > 0:45:54Before returning down the slip face,
0:45:54 > 0:45:57it will drink 40% of its body weight.
0:46:02 > 0:46:08This little beetle has learned how to conjure water out of the air
0:46:08 > 0:46:10in one of the driest places on earth.
0:46:14 > 0:46:17And it's not alone on the top of the dunes.
0:46:24 > 0:46:27Web-footed geckos use a similar trick.
0:46:37 > 0:46:41Surely, few animals go to greater lengths to get a drink.
0:46:59 > 0:47:03Unfortunately, Namaqua chameleons know that on foggy mornings,
0:47:03 > 0:47:08the beetles coming down the dunes are juicier than those going up.
0:47:19 > 0:47:24The diversity of life that thrives in a world almost totally devoid
0:47:24 > 0:47:26of water is truly remarkable.
0:47:29 > 0:47:33Success in the desert depends on an extraordinary variety of
0:47:33 > 0:47:37survival strategies that have evolved over millions of years.
0:47:40 > 0:47:42But our planet is changing.
0:47:45 > 0:47:49The world's deserts are growing bigger, hotter and drier,
0:47:49 > 0:47:52and they're doing so faster than ever before.
0:47:54 > 0:47:59How life will cope here in the future remains to be seen.
0:48:15 > 0:48:20Finding animals in these vast empty landscapes was a persistent problem
0:48:20 > 0:48:21for the Deserts team.
0:48:21 > 0:48:25But surely this wouldn't be the case when they set out to film
0:48:25 > 0:48:28one of the greatest concentrations of wildlife on earth.
0:48:31 > 0:48:35It can't be hard to find a billion locusts, can it?
0:48:39 > 0:48:40OK.
0:48:40 > 0:48:43With news that freak rains have triggered
0:48:43 > 0:48:46a mass emergence of locusts in a remote part of Madagascar,
0:48:46 > 0:48:48the team sets off in pursuit.
0:48:56 > 0:48:58We've got some young hopper locusts just crossing the road
0:48:58 > 0:49:01in front of us here. We've just had to stop the cars.
0:49:01 > 0:49:04Here they are, here, all on the side of the road, look.
0:49:04 > 0:49:06It looks promising.
0:49:06 > 0:49:08But though finding hoppers is easy,
0:49:08 > 0:49:11filming them proves more of a challenge.
0:49:11 > 0:49:14Can we rethink this? Because it's not really working.
0:49:14 > 0:49:15The locusts are really skippy.
0:49:15 > 0:49:18Any kind of movement, they just freak out, So we're now doing
0:49:18 > 0:49:21our best locust-herding techniques to try to get them to go
0:49:21 > 0:49:24in front of the lens, which is proving harder than anticipated.
0:49:34 > 0:49:37This is my Monday morning locust-herding jazz hands.
0:49:55 > 0:49:56- Ah! - What? What's that?
0:49:56 > 0:49:58- What?- It's a wasp nest.
0:50:02 > 0:50:05Soon, the crew find themselves surrounded by locusts.
0:50:05 > 0:50:08No need for jazz hands now.
0:50:12 > 0:50:16It's a good start, but the team still need to film the winged swarms
0:50:16 > 0:50:18that complete the story.
0:50:22 > 0:50:26But, once airborne, they can travel 60 miles a day,
0:50:26 > 0:50:28so finding a swarm won't be easy.
0:50:31 > 0:50:35Fortunately, the UN's Food and Agriculture Organisation
0:50:35 > 0:50:37are here, too, to help.
0:50:41 > 0:50:44The FAO are on a mission to eradicate the plagues
0:50:44 > 0:50:47decimating crops across Madagascar,
0:50:47 > 0:50:52and if anyone knows where the locusts are,
0:50:52 > 0:50:55it's the local expert, Hasibelo.
0:50:55 > 0:50:58He thinks that they are moving this way.
0:51:01 > 0:51:03Time to go swarm-chasing.
0:51:06 > 0:51:09But chasing is the operative word.
0:51:09 > 0:51:12The locusts always seem one step ahead.
0:51:14 > 0:51:17It's amazing, really, because this plan's completely
0:51:17 > 0:51:20radically changing, hour by hour. We now have to travel
0:51:20 > 0:51:23several hours further north, which is...
0:51:23 > 0:51:25- a bit of a pain. - It's a bit of a pain.
0:51:28 > 0:51:30As they venture into the unknown,
0:51:30 > 0:51:33it's clear it's been a very wet year indeed.
0:51:40 > 0:51:45Traffic is one thing, but boats on the road?
0:51:45 > 0:51:46Unconventional traffic.
0:51:51 > 0:51:54Progress is slow, and soon stops altogether.
0:52:00 > 0:52:04The locusts are just across the water, so the team must follow...
0:52:07 > 0:52:09..on this.
0:52:11 > 0:52:13What could possibly go wrong?
0:52:18 > 0:52:22We're now stuck on, possibly, the world's most antiquated raft
0:52:22 > 0:52:25trying to cross a very fast-flowing river.
0:52:25 > 0:52:27But, onwards and upwards.
0:52:27 > 0:52:31We've now got an hour-long river crossing, and we'll just have to see
0:52:31 > 0:52:32what's on the other side.
0:52:49 > 0:52:53With the river behind them, it should be plain sailing.
0:52:57 > 0:53:01But once across, the team discovers that, yet again,
0:53:01 > 0:53:03the locusts are nowhere to be seen.
0:53:10 > 0:53:12And, after two weeks on the road,
0:53:12 > 0:53:15the local street food is beginning to take its toll.
0:53:19 > 0:53:23So Ed's not very well. Been yacking up and...
0:53:24 > 0:53:27And not very nice stomach.
0:53:27 > 0:53:29We just need to do whatever it takes now
0:53:29 > 0:53:32to get us to where the swarms are.
0:53:32 > 0:53:34The next day, the team forges on.
0:53:37 > 0:53:38Briefly.
0:53:42 > 0:53:45Here's Jamal, our driver.
0:53:45 > 0:53:46What do we think? Yeah?
0:53:47 > 0:53:49No?
0:53:49 > 0:53:52The road has turned into a bog.
0:53:52 > 0:53:55The cars can go no further.
0:53:55 > 0:53:58We need to cross this area of water to get to the savanna
0:53:58 > 0:54:00and find our locust swarms.
0:54:01 > 0:54:04And it's amazing to think that, with the combined might of the
0:54:04 > 0:54:10United Nations and the BBC, we are eventually defeated by a puddle.
0:54:12 > 0:54:14Back to the drawing board.
0:54:18 > 0:54:21Once again, it's Hasibelo to the rescue.
0:54:22 > 0:54:24Well, we have a plan.
0:54:27 > 0:54:30Taking to the air was never on the cards,
0:54:30 > 0:54:32but thanks to the FAO's helicopter,
0:54:32 > 0:54:36the team can now play the locusts at their own game.
0:55:00 > 0:55:01More smoke?
0:55:05 > 0:55:08This time, it's a billion locusts...
0:55:16 > 0:55:19..and one very relieved producer.
0:55:32 > 0:55:35Woohoo!
0:55:35 > 0:55:39Against the odds, the team has located a super-swarm.
0:55:57 > 0:56:00This is exactly what we've been looking for. We've driven halfway
0:56:00 > 0:56:03across Madagascar to one of the most remote parts there is.
0:56:03 > 0:56:07It's just been a nightmare, but, finally, we're here.
0:56:07 > 0:56:10I mean, this is the biggest swarm we could have even hoped for.
0:56:10 > 0:56:11It is just amazing.
0:56:11 > 0:56:13Look at here, I'm going to film here.
0:56:15 > 0:56:18It's incredibly exhilarating, and yet totally shocking,
0:56:18 > 0:56:22to think of the devastation that swarms like this are causing.
0:56:22 > 0:56:25It just makes you realise how important the FAO are
0:56:25 > 0:56:27in getting this under control.
0:56:31 > 0:56:32I'm just going to run through it.
0:56:32 > 0:56:34I should be naked for this, but...
0:56:49 > 0:56:54Thankfully, Rob kept his clothes on, and, more importantly,
0:56:54 > 0:56:56this plague has now been halted,
0:56:56 > 0:57:00but not before the team had witnessed one of the biggest swarms
0:57:00 > 0:57:01ever recorded on film.
0:57:14 > 0:57:19Next time, we journey to the world's great plains,
0:57:19 > 0:57:24where spectacular gatherings of wildlife cope with extreme change...
0:57:26 > 0:57:30..and surprising creatures survive in unexpected ways.