0:00:38 > 0:00:42A third of the land on our planet is desert.
0:00:51 > 0:00:57These great scars on the face of the Earth appear to be lifeless,
0:00:57 > 0:01:00but surprisingly none are.
0:01:05 > 0:01:11In all of them, life manages somehow to keep a precarious hold.
0:01:31 > 0:01:34Not all deserts are hot.
0:01:34 > 0:01:36Fifty-mile-an-hour winds,
0:01:36 > 0:01:41blowing in from Siberia, bring snow to the Gobi Desert in Mongolia.
0:02:06 > 0:02:10From a summer high of 50 degrees centigrade,
0:02:10 > 0:02:14the temperature in mid-winter can drop to minus 40,
0:02:14 > 0:02:18making this one of the harshest deserts of all.
0:02:26 > 0:02:31Few animals can survive these extreme changes.
0:02:37 > 0:02:44Wild Bactrian camels, one of the rarest mammals on the planet,
0:02:44 > 0:02:46and perhaps the hardiest.
0:02:46 > 0:02:51Their biggest problem is the lack of water, particularly now in winter
0:02:51 > 0:02:54when the little there is, is locked up as ice.
0:03:00 > 0:03:05Surprisingly, snow here never melts.
0:03:05 > 0:03:09The air is just too cold and too dry for it to do so.
0:03:15 > 0:03:18The sun's rays turn it straight into vapour.
0:03:18 > 0:03:20It evaporates.
0:03:27 > 0:03:35But it is the only source of water, so Bactrian camels eat it.
0:03:35 > 0:03:38Elsewhere in the world, a camel at a waterhole can drink
0:03:38 > 0:03:42as much as two hundred litres during a single visit.
0:03:44 > 0:03:49Here the strategy is to take little and often, and with good reason,
0:03:49 > 0:03:53for filling the stomach with snow could be fatal.
0:03:58 > 0:04:04The camels must limit themselves to the equivalent of just ten litres a day.
0:04:14 > 0:04:17LOUD MATING CALL
0:04:20 > 0:04:23Winter is the time for breeding.
0:04:27 > 0:04:32This extraordinary performance is a male Bactrian camel's way
0:04:32 > 0:04:35of attracting the attention of a passing female.
0:04:37 > 0:04:42In summer, the camels can't stray far from waterholes,
0:04:42 > 0:04:45but now, with mouthfuls of snow lying everywhere,
0:04:45 > 0:04:48they can travel widely in search of mates.
0:04:52 > 0:04:58Today, less than a thousand of these desert specialists remain in the wild.
0:04:58 > 0:05:04The Gobi, hostile though it is, is their last stronghold.
0:05:09 > 0:05:13There is no other desert quite like the Gobi.
0:05:13 > 0:05:17But why is this place a desert?
0:05:17 > 0:05:22There is one simple and massive cause - the Himalayas.
0:05:26 > 0:05:30Clouds blowing from the south hit this gigantic barrier.
0:05:30 > 0:05:34As they are forced upwards, so they empty their moisture on the
0:05:34 > 0:05:39mountain slopes, leaving little for the land on the other side.
0:05:43 > 0:05:47From space, deserts are very conspicuous.
0:05:49 > 0:05:54Dunes of sand, hundreds of miles long, streak their surface.
0:05:59 > 0:06:02With no cloak of vegetation to conceal them,
0:06:02 > 0:06:06strange formations are exposed in the naked rock.
0:06:12 > 0:06:16Africa's Sahara is the largest desert of all.
0:06:16 > 0:06:18It's the size of the United States
0:06:18 > 0:06:23and the biggest source of sand and dust in the entire world.
0:07:01 > 0:07:05Sandstorms like these appear without warning
0:07:05 > 0:07:09and reduce visibility for days over areas the size of Britain.
0:07:18 > 0:07:23Dromedaries, single-humped camels, take these storms in their stride.
0:07:27 > 0:07:31The heavy sand rises only a few metres above the ground,
0:07:31 > 0:07:36but the dust can be blown five thousand metres up into the sky.
0:07:41 > 0:07:48The ferocious wind, armed with grains of sand, is the agent that shapes all deserts.
0:07:57 > 0:08:03Reptiles have armoured scaly skins that protect them from the stinging grains.
0:08:06 > 0:08:11For insects, the bombardment can be very severe indeed.
0:08:13 > 0:08:16The only escape is below the surface.
0:08:32 > 0:08:39As the winds rise and fall, swirl and eddy, so they pile the sand into dunes.
0:08:43 > 0:08:47These sand seas can be hundreds of miles across.
0:08:51 > 0:08:53In Namibia,
0:08:53 > 0:08:56the winds have built some of the biggest dunes in the world.
0:09:03 > 0:09:08Star dunes, like these, can be three hundred metres high.
0:09:08 > 0:09:15Grains swept up the flanks are blown off the crests of the ridges, so it's only the tops that are moving.
0:09:22 > 0:09:27The main body of these dunes may not have shifted for 5,000 years.
0:09:38 > 0:09:45Few rocks can resist the continuous blast of the sand-carrying wind.
0:09:45 > 0:09:50These outcrops are standing in Egypt's White Desert,
0:09:50 > 0:09:53but they will not do so for much longer.
0:09:54 > 0:10:00They are being inexorably chiselled away and turned into more sand.
0:10:37 > 0:10:44Now lumps of heavily-eroded rocks have been marooned in a sea of sand.
0:11:00 > 0:11:04These jagged pyramids, a hundred metres tall,
0:11:04 > 0:11:08were once part of a continuous rocky plateau.
0:11:08 > 0:11:12The blasting sand will eventually eliminate them altogether.
0:11:20 > 0:11:25The relentless power of the wind ensures that the face of a desert
0:11:25 > 0:11:27is continually changing.
0:11:27 > 0:11:30But there is one constant presence...
0:11:37 > 0:11:40..the desert sun.
0:11:54 > 0:11:58The sun's heat and power to evaporate water has had a profound
0:11:58 > 0:12:02effect on the bodies and habits of everything that lives here.
0:12:06 > 0:12:11This sun, potentially, is a killer,
0:12:11 > 0:12:16and the red kangaroos must acknowledge that.
0:12:16 > 0:12:19Right now, while the sun is low,
0:12:19 > 0:12:22there is no immediate cause for concern.
0:12:22 > 0:12:26But this situation won't last long.
0:12:26 > 0:12:29Australia is the world's most arid continent
0:12:29 > 0:12:32with blistering daytime temperatures.
0:12:38 > 0:12:44Every hour the temperature rises by five degrees centigrade.
0:12:51 > 0:12:55Soon the heat will reach a critical point.
0:13:04 > 0:13:10Any kangaroo out in the open is in serious danger of overheating.
0:13:15 > 0:13:21In the full sun, the temperature on the ground soars to 70 degrees.
0:13:25 > 0:13:31By midday, the radiation is so intense they must take shelter.
0:13:51 > 0:13:55In the shade, they are shielded from much of the sun's energy,
0:13:55 > 0:13:57but their body temperature can still rise.
0:14:00 > 0:14:03So they lick saliva onto their forearms,
0:14:03 > 0:14:05where there is a network of blood vessels
0:14:05 > 0:14:12close to the surface of the skin, and as the saliva evaporates, their blood is cooled.
0:14:14 > 0:14:19This thermal image shows just how effective the process is.
0:14:19 > 0:14:23The blue areas on the body are the cooler parts.
0:14:31 > 0:14:37As the saliva dries, it has to be replaced, and this is a real drain
0:14:37 > 0:14:39on the kangaroo's body fluids.
0:14:49 > 0:14:54Even in the shade, the earth is baking hot,
0:14:54 > 0:14:58so the kangaroos dig away the warmed top soil to get at
0:14:58 > 0:15:00the cooler ground beneath.
0:15:22 > 0:15:27By staying in the shade and licking to control their body temperature,
0:15:27 > 0:15:29kangaroos manage to get through
0:15:29 > 0:15:32the hottest part of the day without heat stroke.
0:15:32 > 0:15:35But for the majority of desert animals,
0:15:35 > 0:15:39this strategy would not be enough for survival.
0:16:00 > 0:16:06The extraordinary ears of the fennec foxes of Africa radiate heat,
0:16:06 > 0:16:09but the animals have another way of keeping cool.
0:16:18 > 0:16:23They spend their days underground and only emerge at sunset.
0:16:35 > 0:16:38Darkness brings huge changes.
0:16:38 > 0:16:41In the Sahara, the temperature can drop as much as
0:16:41 > 0:16:43thirty degrees during the night,
0:16:43 > 0:16:47so it is cool enough to allow these desert fox cubs to play.
0:16:54 > 0:16:57All sorts of creatures now appear,
0:16:57 > 0:17:01including some really unexpected ones.
0:17:03 > 0:17:08Toads have permeable skins and would quickly die from desiccation
0:17:08 > 0:17:10out in the daytime heat.
0:17:10 > 0:17:12It is only now that they can leave shelter.
0:17:14 > 0:17:17The same is true for scorpions,
0:17:17 > 0:17:20even though their shells are actually watertight.
0:17:32 > 0:17:37In fact, most small desert creatures are nocturnal, so it's only now
0:17:37 > 0:17:43that you can judge just how much life there can be in a desert.
0:17:43 > 0:17:47But moisture lost, even at night, has to be replaced some time,
0:17:47 > 0:17:48somehow.
0:17:48 > 0:17:52And that problem dominates the lives of all desert dwellers.
0:18:00 > 0:18:06The Atacama in Chile. This is the driest desert in the world.
0:18:07 > 0:18:12Some parts may not see rain for fifty years, and with such a record
0:18:12 > 0:18:15you would expect the place to be completely barren.
0:18:20 > 0:18:24These are South America's camels - guanacos.
0:18:26 > 0:18:29They are very good at conserving moisture,
0:18:29 > 0:18:32but they nonetheless need a regular supply of water.
0:18:44 > 0:18:47They get it partly from cactus flowers,
0:18:47 > 0:18:51but that explanation raises another question.
0:18:53 > 0:18:57How do the cacti survive without rain?
0:19:03 > 0:19:08Hot winds suck all the moisture from the surface of the land.
0:19:09 > 0:19:15Clearly there must be something else that takes the place of rain.
0:19:15 > 0:19:21The secret is a cold sea current that runs parallel to the land.
0:19:38 > 0:19:41The cold water cools the moist, warm air above it
0:19:41 > 0:19:44and that produces banks of fog.
0:20:06 > 0:20:12At the same time, wind blowing on to the shore sweeps the fog inland.
0:20:27 > 0:20:32Before long the cacti are dripping with dew.
0:20:40 > 0:20:44The fog is so regular that moisture-loving lichens
0:20:44 > 0:20:49are able to grow on the cacti and they absorb liquid like a sponge.
0:20:51 > 0:20:53In a land of almost no rain,
0:20:53 > 0:20:59these precious drops are life-savers for many different creatures.
0:21:08 > 0:21:12Further inland, the air remains so warm that its moisture
0:21:12 > 0:21:16does not condense, so this slender strip of desert
0:21:16 > 0:21:20is virtually the only part of the Atacama where life can exist.
0:21:24 > 0:21:29And without the fog, this land too would be empty.
0:21:42 > 0:21:46The guanacos make the most of the dew,
0:21:46 > 0:21:48but it will not remain for long.
0:21:48 > 0:21:50In an hour or two,
0:21:50 > 0:21:55the sun will have burnt it off and dried the surface of the cacti.
0:22:02 > 0:22:08The Sonoran Desert in Arizona is not quite so dry as the Atacama.
0:22:08 > 0:22:10Some rain does fall,
0:22:10 > 0:22:14but it is infrequent and when it does arrive,
0:22:14 > 0:22:18animals and plants have to be ready to make the most of it.
0:22:20 > 0:22:21And it's coming.
0:22:29 > 0:22:33When the summer monsoon blows in, the giant saguaros, one of the
0:22:33 > 0:22:38biggest of all cacti, are ready to take full advantage of it.
0:23:10 > 0:23:17After a rainstorm, the saguaro's long shallow root system sucks up the water,
0:23:17 > 0:23:21and the pleats on its trunk enable it to expand rapidly.
0:23:29 > 0:23:35When full, a saguaro stem can store up to five tons of water,
0:23:35 > 0:23:39and that's enough to see it through many months of drought.
0:23:43 > 0:23:48The trunks of these huge plants provide homes for the Gila woodpecker.
0:23:50 > 0:23:54But birds are not the only animals to benefit
0:23:54 > 0:23:56from the presence of the cacti.
0:24:12 > 0:24:15During four weeks of the summer
0:24:15 > 0:24:20the saguaros bloom - at night - to attract visitors.
0:24:23 > 0:24:28The pollen and nectar with which these flowers are loaded attract
0:24:28 > 0:24:31long-nosed - and long-tongued - bats.
0:24:45 > 0:24:50The bats left Mexico a few days earlier to escape the heat of summer
0:24:50 > 0:24:55and are on their way north to the southern United States.
0:24:56 > 0:25:00To get there they have to cross the Sonoran Desert.
0:25:06 > 0:25:08But the desert is so big
0:25:08 > 0:25:13that for most of the year they would be unable to cross it.
0:25:13 > 0:25:17Now, with the saguaro in bloom, they can refuel on the way.
0:25:26 > 0:25:30So the saguaro's success in developing a way to store water
0:25:30 > 0:25:32is now crucial
0:25:32 > 0:25:36to most of the animals that live or even travel through this land.
0:26:14 > 0:26:19The scarcity of rain determined the shape of this icon of the desert,
0:26:19 > 0:26:21but water, scarce though it is,
0:26:21 > 0:26:26has also, like the wind, shaped the land itself.
0:26:41 > 0:26:43In the deserts of Utah,
0:26:43 > 0:26:47ancient rivers flowing across sandstone country
0:26:47 > 0:26:49steadily widened their canyons
0:26:49 > 0:26:53until now the land between them has been reduced
0:26:53 > 0:26:55to spires and pinnacles.
0:27:23 > 0:27:29With little or no soil to retain water on the surface of the land,
0:27:29 > 0:27:32life here is scarce indeed.
0:27:33 > 0:27:38And when resources are limited, conflict is never far away.
0:27:48 > 0:27:50These are Nubian ibex,
0:27:50 > 0:27:53and they are squaring up for a duel.
0:27:59 > 0:28:04And when trouble starts, a smart ibex knows that the best thing to do
0:28:04 > 0:28:06is to gain higher ground.
0:28:23 > 0:28:26These are actually subordinate male ibex
0:28:26 > 0:28:29but their fights are, nonetheless, serious.
0:28:29 > 0:28:33Losing one might mean never getting the chance to breed - ever.
0:28:55 > 0:28:59When competitors are evenly matched, as they are here,
0:28:59 > 0:29:01duels can last for an hour.
0:29:20 > 0:29:24In this heat, the effort is truly exhausting,
0:29:24 > 0:29:26PANTING GRUNTS
0:29:26 > 0:29:31but victory here will gain important ranking points
0:29:31 > 0:29:33on a male's way to the top.
0:30:03 > 0:30:06There's so much at stake that not all play fair.
0:30:21 > 0:30:24The battle has produced a winner,
0:30:24 > 0:30:27but the ultimate prize is not his yet.
0:30:30 > 0:30:35That currently belongs to the dominant male ibex.
0:30:37 > 0:30:41His rank earns him the loyalty of a harem of females
0:30:41 > 0:30:45and they follow him closely as he travels across this desert
0:30:45 > 0:30:47searching for food and water.
0:30:48 > 0:30:52He doesn't have to waste time looking for mates -
0:30:52 > 0:30:54they're his for the taking.
0:30:54 > 0:30:58So he can concentrate, with them, on keeping fit and healthy.
0:31:12 > 0:31:16Lizards are desert specialists,
0:31:18 > 0:31:23but here, their numbers are extraordinary.
0:31:28 > 0:31:30These crevices in South Africa contain
0:31:30 > 0:31:34the highest density of lizards in the world.
0:31:43 > 0:31:47They are called flat lizards, for obvious reasons,
0:31:47 > 0:31:52and they flaunt their multi-coloured bellies in territorial disputes.
0:31:54 > 0:32:00He's made his point, and now it's time to find some food.
0:32:00 > 0:32:05As the day warms up, the lizards move away from their cracks
0:32:05 > 0:32:08and head down to the bottom of the gorge.
0:32:08 > 0:32:10Their goal is the river.
0:32:12 > 0:32:18There is no food at the edge, but this desert river holds a secret.
0:32:24 > 0:32:30Each day, blackfly rise from turbulent stretches of the river.
0:32:30 > 0:32:33This is what the lizards have come for.
0:32:47 > 0:32:53The blackfly never land, so the lizards have to leap for their food.
0:33:05 > 0:33:06In one day,
0:33:06 > 0:33:11each of these acrobatic little lizards may catch fifty flies.
0:33:21 > 0:33:23There are plenty of flies to go round,
0:33:23 > 0:33:26even with hundreds of lizards competing for them.
0:33:40 > 0:33:42Away from these rapids,
0:33:42 > 0:33:46flat-lizard populations are found in much smaller numbers,
0:33:46 > 0:33:51but here, one unusual abundance has produced another.
0:34:01 > 0:34:04Deserts are created by the lack of water,
0:34:04 > 0:34:08but what actually kills animals here is not heat or thirst
0:34:08 > 0:34:11but lack of food.
0:34:12 > 0:34:15DEEP VOCAL RUMBLE
0:34:28 > 0:34:32So how on earth does a plant-eater this size survive
0:34:32 > 0:34:38in a place apparently totally devoid of vegetation?
0:34:43 > 0:34:48Elephants in Namibia are the toughest in Africa,
0:34:48 > 0:34:50and they need to be.
0:35:05 > 0:35:09What little food exists is so dispersed
0:35:09 > 0:35:13that these elephants walk up to 50 miles a day as they travel
0:35:13 > 0:35:18up the dry river channels searching for something to eat.
0:35:32 > 0:35:36At times, the task looks truly hopeless.
0:36:09 > 0:36:13Elephants may seem out of place in this landscape,
0:36:13 > 0:36:16but they are not the only ones.
0:36:31 > 0:36:35Amazingly, lions live here too.
0:36:39 > 0:36:40In savannah country,
0:36:40 > 0:36:45huge herds of game support prides containing 20 lions or more.
0:36:45 > 0:36:50But to live here, lions have had to change their habits.
0:36:50 > 0:36:55Prides are much smaller, and their home ranges are very much bigger.
0:36:55 > 0:36:58And there's an added problem.
0:36:58 > 0:37:02Their food is always on the move.
0:37:10 > 0:37:12Like the elephants,
0:37:12 > 0:37:17the lions must travel great distances to find enough to live on.
0:37:31 > 0:37:34But lions can't go everywhere.
0:37:34 > 0:37:38They won't attempt to cross this field of sand dunes,
0:37:38 > 0:37:40and the oryx know it.
0:38:38 > 0:38:42The lions must wait for the oryx to leave the safety of the dunes -
0:38:42 > 0:38:45which eventually they must, to find food and water -
0:38:45 > 0:38:48and then the lions will ambush them.
0:39:50 > 0:39:54The elephants have found some of their favourite food.
0:40:01 > 0:40:04Grasses are the staple diet of all elephants,
0:40:04 > 0:40:07but this herd concentrates on digging up the roots,
0:40:07 > 0:40:11which have more nutrition and moisture than the stems.
0:40:11 > 0:40:15It's the sort of behaviour that can make all the difference
0:40:15 > 0:40:17in a place of serious shortages.
0:40:18 > 0:40:20Yet all this can change
0:40:20 > 0:40:22in an instant.
0:40:37 > 0:40:42The fortunes of many deserts are ruled by distant rains.
0:40:42 > 0:40:47This water fell as rain in mountains more than a hundred miles away.
0:40:52 > 0:40:54It's known as a flash flood
0:40:54 > 0:40:59and called that because the water may run for just a single day.
0:40:59 > 0:41:03It's an event that only happens once or twice a year at the most.
0:41:23 > 0:41:28The sandy river-bed acts like a giant strip of blotting paper,
0:41:28 > 0:41:31sucking up the water as soon as it appears.
0:41:40 > 0:41:44But every square metre of soil moistened by this river
0:41:44 > 0:41:47will increase the chances of survival
0:41:47 > 0:41:49for those that live here.
0:41:53 > 0:41:57Water holes are filled temporarily.
0:42:01 > 0:42:05Elsewhere in Africa, elephants drink every day,
0:42:05 > 0:42:11but the lack of water here means that desert elephants can only refill their tanks
0:42:11 > 0:42:13once every four or five days.
0:42:13 > 0:42:17Within a week the flash-flood has produced a flush of green,
0:42:17 > 0:42:22more than enough to draw the oryx out of the dunes.
0:42:24 > 0:42:27It's a rare chance for them to build up their food reserves.
0:42:36 > 0:42:40The flood has made life easier for the lions, too.
0:42:42 > 0:42:47The flesh of this oryx will keep the family going for a week at the most
0:42:47 > 0:42:50but for a while, the hunting will be easier
0:42:50 > 0:42:53now that the river channel has turned green.
0:42:56 > 0:43:00The good times for lions and oryx are brief,
0:43:00 > 0:43:03but these are the short moments that make it possible
0:43:03 > 0:43:05to live in deserts the year round.
0:43:11 > 0:43:15Death Valley is the hottest place on earth,
0:43:15 > 0:43:19yet even this furnace can be transformed by water.
0:43:29 > 0:43:30A single shower
0:43:30 > 0:43:34can enable seeds that have lain dormant for 30 years or more
0:43:34 > 0:43:36to burst into life.
0:43:43 > 0:43:48And there hasn't been a bloom like this one for a century.
0:44:00 > 0:44:03The periods of boom in Death Valley are short.
0:44:03 > 0:44:07But they're just frequent enough to keep life ticking over.
0:44:15 > 0:44:20A sudden flush of vegetation is what every desert dweller waits for
0:44:20 > 0:44:24and, when it happens, they must make the most of it.
0:44:43 > 0:44:47There is no other species on the planet that responds as quickly
0:44:47 > 0:44:52and as dramatically to the good times as the desert locust.
0:44:52 > 0:44:57Eggs that have remained in the ground for 20 years begin to hatch.
0:45:09 > 0:45:11The young locusts are known as "hoppers"
0:45:11 > 0:45:14for at this stage they're flightless.
0:45:14 > 0:45:16They find new feeding grounds
0:45:16 > 0:45:20by following the smell of sprouting grass.
0:45:26 > 0:45:30Normally it takes four weeks for hoppers to become adults
0:45:30 > 0:45:33but, when the conditions are right, as now,
0:45:33 > 0:45:36their development switches to the fast track.
0:45:41 > 0:45:46As the vegetation in one place begins to run out, the winged adults release pheromones -
0:45:46 > 0:45:51scent messages - which tell others in the group that they must move on.
0:46:02 > 0:46:06And when groups merge, they form a swarm.
0:46:28 > 0:46:32An adult locust eats its entire bodyweight every day,
0:46:32 > 0:46:37and a whole swarm can consume literally hundreds of tons of vegetation.
0:46:38 > 0:46:42They HAVE to keep on moving.
0:46:42 > 0:46:45The swarm travels with the wind.
0:46:45 > 0:46:48It's the most energy-saving way of flying.
0:46:51 > 0:46:56Following the flow of wind means that they are always heading towards areas of low pressure -
0:46:56 > 0:47:02places where wind meets rain, and vegetation starts to grow.
0:47:03 > 0:47:08As they fly, swarms join up with other swarms
0:47:08 > 0:47:12to form gigantic plagues several billion strong
0:47:12 > 0:47:15and as much as 40 miles wide.
0:47:15 > 0:47:20They will consume every edible thing that lies in their path.
0:47:33 > 0:47:37This is one of Planet Earth's greatest spectacles.
0:47:37 > 0:47:41It's rarely seen on this scale and it won't last long.
0:47:41 > 0:47:43Once the food has gone,
0:47:43 > 0:47:49the steady roar of a billion beating locust wings will once again be replaced
0:47:49 > 0:47:53by nothing more than the sound of the desert wind.
0:48:08 > 0:48:11Of all the places visited by the Planet Earth team,
0:48:11 > 0:48:14the most remote was Mongolia's Gobi desert.
0:48:14 > 0:48:19This was the location for one of the most remarkable desert animals of all,
0:48:19 > 0:48:22the elusive wild Bactrian camels.
0:48:27 > 0:48:30The trip required months of planning
0:48:30 > 0:48:33but arriving in Mongolia's capital, Ulaanbaatar,
0:48:33 > 0:48:38was merely the start of what was to be the most challenging of shoots.
0:48:38 > 0:48:42We're going for a two-month trip, and basically this area is so remote
0:48:42 > 0:48:45that we take everything we need with us.
0:48:45 > 0:48:48Two months' supply of food, fuel.
0:48:48 > 0:48:51And in the area we are going to there is no viable source of water
0:48:51 > 0:48:53so we have to bring that in, too.
0:48:53 > 0:48:56It really is a quest. And the quest for camels begins today.
0:48:56 > 0:49:02From Ulaanbaatar, the team were going to have to travel for a further five days
0:49:02 > 0:49:05to get to where the camels live.
0:49:06 > 0:49:11Despite its huge size, Mongolia has only 500 miles of paved road.
0:49:11 > 0:49:15So it wasn't long before they were heading cross-country.
0:49:15 > 0:49:21But even their off-road vehicles were to struggle in this terrain.
0:49:25 > 0:49:30And with few vehicles, petrol stations were rather Heath-Robinson affairs,
0:49:30 > 0:49:34without any of the usual safety considerations.
0:49:38 > 0:49:41The Gobi desert is as large as Holland,
0:49:41 > 0:49:45but surprisingly difficult to find without any roads or signs.
0:49:45 > 0:49:50CONVERSATION IN MONGOLIAN AND RUSSIAN
0:49:50 > 0:49:54The team were heading for the outer part of Outer Mongolia
0:49:54 > 0:49:57and, in this vast, remote and rugged wilderness
0:49:57 > 0:50:00they were going to have to find a group of animals
0:50:00 > 0:50:03whose population numbered a mere 800.
0:50:10 > 0:50:16The small community of Bayantorol was the gateway to the Gobi Desert
0:50:16 > 0:50:19and home to an expert tracker called Choi Jin.
0:50:19 > 0:50:22His skills were vital in the search for wild camels.
0:50:22 > 0:50:25And it appeared the camels needed him, too.
0:50:25 > 0:50:27He killed two wolves which...
0:50:29 > 0:50:31Which killed...five?
0:50:38 > 0:50:42- 50- camels. Two wolves killed 50 camels.
0:50:42 > 0:50:45This is what he tells us now.
0:50:45 > 0:50:49Choi Jin has been tracking wild camels for 50 years
0:50:49 > 0:50:55so if anyone was going to get Henry to within filming distance of these elusive animals, then it was him.
0:50:56 > 0:51:01Reliable vehicles were also vital to the success of the trip.
0:51:01 > 0:51:08The team's Russian-made supply vehicle may have needed to be warmed up with a blowtorch each morning,
0:51:08 > 0:51:12but in the event of a breakdown they would be more than covered
0:51:12 > 0:51:17by the collection of spare parts brought along by the Mongolian drivers.
0:51:17 > 0:51:24It was comforting to know that here was a vehicle whose engine could be rebuilt by a man with a file
0:51:24 > 0:51:27in the middle of the Gobi desert.
0:51:27 > 0:51:31Fortunately, they weren't depending on it for a quick getaway.
0:51:31 > 0:51:34MOTOR GRINDS ENGINE KNOCKS
0:51:37 > 0:51:41Since leaving Ulaanbaatar, the team had driven 1,500 miles
0:51:41 > 0:51:43through the middle of Mongolia.
0:51:43 > 0:51:49The supply vehicle had done the same, but they'd had to give it several days' head start.
0:51:54 > 0:51:56But before leaving Bayantorol,
0:51:56 > 0:52:01the team had had to deal with some local politics, as Tom explains.
0:52:02 > 0:52:04Our interpreter...
0:52:04 > 0:52:08decided to pick a fight
0:52:08 > 0:52:11with the stand-in head of the park
0:52:11 > 0:52:14and head-butted him in the face...
0:52:14 > 0:52:17which is not ideal for relations.
0:52:17 > 0:52:22Anyway, our driver, who was also very drunk,
0:52:22 > 0:52:26decided that this was his chance to step in.
0:52:26 > 0:52:28He's a big lad and...
0:52:28 > 0:52:32He then punched our interpreter in the face.
0:52:35 > 0:52:37Yeah, he knocked him flat.
0:52:38 > 0:52:42Luckily, there were no hard feelings the following morning,
0:52:42 > 0:52:47and the team were able to get on with the serious business of finding wild camels.
0:52:47 > 0:52:53It wasn't long before Choi Jin spotted some promising signs.
0:52:53 > 0:52:58Apparently one of the ways in which you can tell how fresh the prints are
0:52:58 > 0:53:00is very, very small detail.
0:53:00 > 0:53:05If he sees a small stone in the print that has got sand on it,
0:53:05 > 0:53:10like that, he knows that it's very recent because otherwise that sand would have blown away.
0:53:10 > 0:53:12It's very loose little grains of sand.
0:53:12 > 0:53:16It's very small, a tiny size. That's why he is walking across such a large area.
0:53:16 > 0:53:22Sure enough, up ahead, the team had their first sighting of wild camels.
0:53:22 > 0:53:24They were already running.
0:53:24 > 0:53:29Poaching has made wild camels very nervous of people.
0:53:29 > 0:53:30They're about 3km or 4km away.
0:53:30 > 0:53:35They spotted us from that distance. That'll be our real problem, getting close to these animals.
0:53:35 > 0:53:38They are capable of spotting us from about 5km
0:53:38 > 0:53:41and running for 70km in the opposite direction.
0:53:41 > 0:53:44This is what is going to make this filming incredibly difficult.
0:53:44 > 0:53:49But we are going to need all Henry's accomplished film skills
0:53:49 > 0:53:52to get us close. We know he can do it.
0:53:52 > 0:53:55- What do you think?- ..I don't know.
0:53:57 > 0:53:59It was easy to understand Henry's doubts
0:53:59 > 0:54:03when faced with the sheer scale of the landscape,
0:54:03 > 0:54:06the scarcity of camels and their fear of people.
0:54:08 > 0:54:14After their first sighting, the team saw nothing for five days.
0:54:16 > 0:54:18So, Choi Jin told us
0:54:18 > 0:54:20he had spotted...
0:54:20 > 0:54:23three or four miles away, very far.
0:54:23 > 0:54:26Can barely tell what it is.
0:54:26 > 0:54:28Sometimes I wonder how we do it,
0:54:28 > 0:54:32how he does it, because it's just watching patterns, changing patterns
0:54:32 > 0:54:35and the heat haze on the horizon.
0:54:35 > 0:54:39But at this distance, they weren't going to get any useful footage.
0:54:39 > 0:54:41A lucky break was needed.
0:54:41 > 0:54:46And an overnight snowstorm didn't seem to be it.
0:54:46 > 0:54:50With the temperature plummeting to minus 20 the team - and breakfast -
0:54:50 > 0:54:52needed a thawing out first.
0:54:52 > 0:54:55We are having a competition to see who warms up first -
0:54:55 > 0:54:58my hands or this frozen can of pilchards.
0:54:58 > 0:55:01That's what it's come to.
0:55:01 > 0:55:05Eating frozen pilchards straight out of the tin.
0:55:05 > 0:55:07That's all we've got for breakfast.
0:55:07 > 0:55:09I think I might pass.
0:55:11 > 0:55:16The vehicles were useful for spotting camels but, to get close,
0:55:16 > 0:55:18the team had to be on foot.
0:55:18 > 0:55:22After walking hundreds of miles they were still no nearer to a sequence,
0:55:22 > 0:55:26and it wasn't helped by having one less camel to film.
0:55:28 > 0:55:31Gobi wolves had got to this one first.
0:55:36 > 0:55:38They saw the car.
0:55:38 > 0:55:40Obviously, that's a window...
0:55:42 > 0:55:46The reflection, low sun.
0:55:46 > 0:55:48The rear ends of running camels
0:55:48 > 0:55:52continued to dominate the team's filming.
0:55:52 > 0:55:54And it was beginning to cause frustrations.
0:55:54 > 0:55:56So, no footage today.
0:55:56 > 0:56:01They are supreme long-distance travellers,
0:56:01 > 0:56:03these animals.
0:56:04 > 0:56:09We are finding it difficult to keep up in the vehicle, let alone by foot.
0:56:09 > 0:56:10I am absolutely knackered
0:56:10 > 0:56:17and slightly annoyed that we haven't got the footage that we want the last couple of days.
0:56:17 > 0:56:21I guess it's camels 1, film crew nil.
0:56:28 > 0:56:32Fortunately, Choi Jin's sharp eyes remained on form.
0:56:32 > 0:56:35And when combined with sheer dogged perseverance,
0:56:35 > 0:56:38the team's luck finally began to change.
0:56:43 > 0:56:47Not only did they start getting head-shots of camels,
0:56:47 > 0:56:49but fascinating behaviour.
0:56:49 > 0:56:52INTERMITTENT "CREAKY GATE" SQUEAKS
0:56:52 > 0:56:55Strange mating rituals
0:56:55 > 0:56:58and snow eating.
0:57:00 > 0:57:04Wild camels remain one of our planet's least known animals,
0:57:04 > 0:57:08so this unique footage was much needed publicity
0:57:08 > 0:57:12for a species on the verge of extinction.
0:57:39 > 0:57:43Subtitles by Red Bee Media Ltd
0:57:43 > 0:57:46E-mail subtitling@bbc.co.uk