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