As far as our knowledge allows us to affirm it,
the Earth, our planet, is a unique case in the universe. Even in these most arid regions, we discover life. Around the equator where heat and humidity, these vital elements are particularly dense, there are large forests. Plants and animals proliferate there to the point that
we have not yet been able to identify all the species. Here animals and plants, insects and birds, Man, finally, coexists in intimate and complex communities, dependent on each other. Two-thirds of this unique planet is covered by water, Where life originated. From the oceans, life spread
to the top of the highest mountains. Plants and animals have adapted to different environments.
They have evolved with the transformations of the earth itself. * The Gandak river that has made its way in an astonishing way, Directly through the chain of
highest mountain in the world, the Himalayas. To the east, the Annapurna, more than 8000 meters high,
to the west, even higher, the Dhaulagiri. Their peaks are only 35 km apart and
I find myself at their feet 6000 meters below. This means that this valley is the deepest in the world. At the altitude where we are about 2000 meters, it
is warm enough for animal and plant life, Be rich and abundant on both sides of the valley. These flowers may look familiar to you, they are found in
effect in many gardens around the world. But here they are wild and they grow on
their place of origin. These are rhododendrons, One of the 500 species of the Himalayas. Monkeys,
gray langurs find food there. And it reminds us that the warm plains
southern Nepal and the tropics are not far away. Here also live several species of
pheasants among the most beautiful birds in Asia. The fact that this valley is the deepest in the world allows
to go there in a few days from a tropical site to the base, To polar landscapes at the top and to observe, over the course of the walk, how plants and animals adapt perfectly, To these changing living conditions. At altitude, more rhododendrons but in the hot humidity
of summer, one can still discover on the moss of the trunks, Orchids and on the ground, flowers appear in a tight bouquet to protect each other from night frosts. The fox-sized Himalayan panda is perfectly protected from the cold by its thick fur, And by the fact that hair grows under him
the soles of the feet, keeping them warm, And also preventing him from slipping on the ice. On the ground, barely bigger than the panda, one of the shyest inhabitants of the Himalayan forest, the musk goat. In this tangle of trees in the woods
would have been a considerable handicap to him. The musk goat did not develop them. To attack, the evil has long defenses of 7 to 8 centimeters. As soon as an animal dies, regardless of its size,
the vultures arrive. These are griffon vultures, Very similar to those that swirl in the sky
Indian villages, lower down, at the foot of the hills. They are commonly found up to 2500 meters. Here we are at 3000 meters, the forest
clears up in summer at this altitude, The rains are rare and in winter it is extremely cold. Conditions that only suit the conifer. Despite the altitude, the course of the Gandak is very wide. Strangely, the river does not meander at the foot of the slopes of
these giant mountains, but cut straight through them. For a long time now, the people who live at the foot
hills exploit this extraordinary corridor, Which takes them straight through the Himalayas. Throughout the summer, caravans of mules go up
the valley, laden with barley and buckwheat, Let them barter with the Tibetans in exchange for wool and salt. Higher still remain only small
shrubs and a few clumps of dried grass, Which are nevertheless enough to feed the tahr. A curious
ruminant that is both goat and sheep. Another typical mountain creature is the yellow-billed chough. It rises to the height of the peaks
snow-covered using updrafts. Only still bloom at this altitude
a few plants gathered in a cushion. Near the summits, only lichens remain, To whom the cold allows only a few
growing days per year. However, men live here. To help them
to plow their fields, they use the yak, Who were once at large in the
plains of Tibet and which they domesticated. It is the only large mammal that can
live permanently at these heights. These populations, the Bhotias and the Sherpas are
perfectly adapted to life at high altitude. Their blood is particularly rich in red blood cells, thus carrying more oxygen than that of the inhabitants of the plain. So, once again, the environment
shaped, modified, transformed living species. Whether human or animal. But all these biological adaptations are recent. These immense mountains, these eternal snows, Are far from dating back to the dawn of time. * They are younger, than the plains of India
to the south or the Tibetan Plateau to the north. They rose to their present height ago
about 65 million years old, rising from the bottom of the sea. * So what allows us to make this claim? The proof can be found right here. These slopes are covered with curious fragments, like this one. * It is obviously a petrified shell, a fossil. Although there is no such mollusk today. There are others, sufficiently similar for us to
can affirm that this ancestor also lived in water. Moreover, by analyzing the rock in which it is petrified, we see that it was the origin of sea mud. Yet I'm as far from the sea as it is
is possible to be in the middle of Asia, Thousands of kilometers from the nearest sea, but also some 3200 meters above sea level. So what forces could have raised the sea bed to this height? We now know that these forces are at work. We know that these mountains keep growing and
that continents are still in the process of being created. I am here in Iceland. This fantastic fountain of fire,
which rises to 60 meters, is composed of molten rocks. All around falls fine ash. There are
suffocating drafts, poisonous gases, And it's so hot that I can't get any closer. Regions like these have everything
eternity experienced intense volcanic activity. * At the Giant's Causeway in Ireland 50 million years ago, after forcing their way through the earth's crust, The lavas contracted into strange
prismatic basalt columns. Far from there, in the Hebrides, we find the same
type of columns, but measuring 6 meters high, And covered here with a layer of lava, not yet eroded. These volcanoes in Iceland originate from huge fissures
which open regularly over the entire width of the island. It is in fact the northern end of a
vast mountain range or ocean ridges, Several thousand kilometers. hollowed out from a
deep pit that runs the globe from north to south. * Most of this flaw
covered with streaks of lava is underwater. This is the reason why its existence
was discovered only at the beginning of this century. Starting in Iceland at the edge of the Arctic Circle, it crosses the ocean equidistant from Europe and Africa to the east, From the Americas to the west. In some places it floats
to create volcanic islands the Azores, Cape Verde, Ascension Island, Saint Helena, Tristan da Cunha. Basalt not only forms ridges
oceanic, it overflows on the bottom of the sea. By chemical analysis, it was found that the lava
furthest from the center of the furrow is the oldest. The molten magma therefore springs from the fault,
then solidifies into basalt on either side of it, Basalt which is pushed back by new upwellings of magma,
so that the bottom of the oceans is continually expanding. We do not yet know all the
forces that engender this process, But it seems that at a distance of 80-100 km
below the earth's surface, The heat is such that the molten rock is traversed
by currents that make it spring through the fault, And then flowed on each side of the furrow, carrying
with it the great plates of the earth's crust. It was this movement that led to the separation of Africa
and South America and the creation of the Atlantic Ocean. Similar events occurred in the Pacific.
The large plateau that forms the eastern part of the ocean floor, Is moving towards the west coast of
America. But where it meets the mainland, Driven by a downdraft, it
dives under the earth's crust, Causing a deep trench in the ocean floor. It draws the sediments accumulated on
the bottom together with water. Mixed with magma, these new ingredients constitute
a new mixture enriched in dissolved gas and steam. As it escapes to the surface through faults in the ground, it cools, solidifies and obstructs the access chimneys. The effect is comparable to blocking the
pressure cooker valve. Mont Saint-Hélène, on the Pacific coast of
North America, May 18, 1980, An eruption with a blast 500 times more powerful than that of the Hiroshima bomb ejects more than a cubic kilometer of rock, About a century earlier, in 1883, on the other side of the Pacific, another spectacular eruption took place, On the small island of Krakatoa, between Java and Sumatra. This titanic eruption caused a tidal wave
developing waves over 30 meters high. Three quarters of the island disappeared while two small
Nearby islets were completely covered in ash. 44 years later, another crater rises from the sea. Anak Krakatoa, the child of Krakatoa. It experiences sporadic eruptions,
but it is possible to browse its edges. Sulphurous vapors and gases constantly gush out from the volcano which, as they condense, turn the rock yellow. Volcanoes don't stay active forever. Eventually, changes occur under the crust
earth and the foci of intense heat move. If water filters on the surface, a thermal spring can be created, A geyser like the one in the park
of Yellowstone in North America. The water that springs from these natural fountains is
crystal clear and chemically rich. But so hot that no creature can live there. On the other hand, as soon as it flows on the surface and begins to cool, There is an abundance of bacterial colonies
as well as the formation of algae mats, On which quickly appear insects that come
feed and mate there, these are ephydrides, ehydra, Kinds of flies of a family whose characteristic is
that the larva develops in such strange environments, Than petroleum or formalin. The eggs are deposited on the carpet
hot formed by algae. Each of them has a long white filament like a seed. They are far from safe, they are coveted by moths that climb the algae, by spiders that also Prowl around the colony, by others
flies, finally larger than the ephydrides, And which, too, readily feed on larvae. Thus, the algal carpet shelters and
maintains an interdependent community, Who feeds on the chemicals contained in the water
and which draws its energy from volcanic heat. The colonization of a surface covered with
volcanic ash is particularly difficult. Years after its eruption, Mount Saint Helena
remains a desert land. On Anak Krakatoa, whose existence dates back sixty years, the process of colonization is however underway. Not only are there giant plants like this,
wild sugar cane, but also trees. Here is a filao. And if you want to see the
result of a century of colonization by plants, Look at this older part of Krakatoa. * We know from reports
made a hundred years ago, That at the time there was only a layer of
barren ash several meters thick. In the space of three years, 34 species of plants have reappeared. Ten years later, that number had doubled and appeared,
meanwhile, a hundred races, birds and insects. Some seeds had come floating
from the island of Java, 32 kilometers from here. And the movement continues. Some other seeds
were probably brought by birds, Either on their feet or in their stomachs. There are now several hundred species of plants on the island. The winds finally brought countless flying insects whose descendants now form a large permanent population, Which ensures the pollination of flowers, feeding on their fruits, their leaves, also feeding on each other. Krakatoa and the many other erupting volcanoes
which range between Java, Sumatra, And the other islands in the Indonesian region lie on the fault line of the earth's crust or the basalt plateau, Forming the bottom of the Indian Ocean meets the part
partially submerged from the Asian continent. This junction already existed 65 million years ago,
when India was an isolated island in the middle of this ocean. At this time, the continents moved
and India has moved closer to Asia. The sediments that separated them overlapped over the junction, forming a huge mountain range, the Himalayas. Also, these great peaks of sandstone and limestone culminating at some 8000 meters are not only the highest in the world, But also among the most recent. Moreover, the process continues. india
continues moving north, At an estimated rate of five centimeters per year. It thus settles ever more strongly against the continental mass of Asia, And even if it is infinitesimally,
the Himalayas continue to grow. This is why this ammonite, sea creature,
found here at an altitude of 3200 meters in the Himalayas. This is also why the Gandak River has
managed to carve out a path so perfect, Through the highest mountain range in the world. It flowed south from the ancient Tibetan plateau, long before India's huge mass came into contact with Asia. As the sediments between these two landmasses rose and piled for millions of years, The river maintained its downward course through
the rock as it rose. Today it continues to flow south to the plains of India, through the deepest gorges in the world. Animals and plants have managed to adapt, to live even near the summits, in an environment which, with that of the poles, Is certainly the most inhospitable there is. Water, hundreds of thousands of tons of water
rest, frozen and on the mountains of the world. You would think that this place is one of the least auspicious
to the life. No vegetation grows on its snowfields, And if there is no vegetation and therefore no
food, neither can there be animals, Such as marmots, mice or rabbits. And if there are no herbivores, there can be no
carnivorous, no predators, such as hawks or weasels. In fact, there is a surprising amount of life here, one form of life that exists within the snowfield itself, Because this snow is not white. She is red. This color comes from microscopic algae. It is caused by the light which
reflected on their cell walls, What is practically invisible
when examined under a microscope. Internally they are green by the presence of chlorophyll, thanks to which they use solar energy, To turn carbon dioxide and water into sugar. These substances, together with the minerals dissolved in the melting ice, provide the algae with all the necessary elements, to their survival and reproduction. The heavy snowfalls of winter, will bury them
under a layer of several meters. But in the spring, when the surface of
this layer melts, the algae divide. They develop small eyelashes thanks to which
they reach the surface and the sunlight. As we age, as minerals
dwindle, they change color, Forming huge red spots on the snowfields. It is not easy for plants to
push on steep slopes, The continual transition from the relative mildness of the day to the frosts
of the night makes the stony and shifting ground, Is not conducive to the fixation of plants. As a result, herbivorous animals are rare. These animals in the Himalayan mountains
are blue sheep or bharal. Their agility makes them able to access
to the vegetation of these cliffs. If they are few, rarer still are
animals that might prey on them. During the summer, the snow leopard has
been seen at an altitude of 5400 meters, But when winter comes, he is forced to
withdraw into the valleys, Game is now so scarce that there is barely enough, even over a vast area, to feed a single leopard. Also this animal is a solitary hunter. The great mountains of South America, some of which are volcanic, such as the Cotopaxi, 5900 meters above sea level, Are part of a chain that runs the entire length
of the continent, surrounded by vast cold plains, The altiplano, the slopes of these mountains are home to a vast and varied population of animals adapted to life at high altitudes, And at low temperatures. Here lives the vicuna, it is a kind of wild camel.
Its fine and silky coat effectively protects it from the cold. However, it was he, paradoxically, who led
the vicuña to an almost total disappearance, For the man was chasing her intensely for
the interest represented by this superb wool. The people of the Andes have domesticated another wild camel, the Guanaco, which not only provides them with excellent wool, But he also serves as draft animals. In Ecuador and Peru, near the equatorial line,
these animals live up to more than 4000 meters of altitude. Further south, in Patagonia and Tierra del Fuego, the
guanaco, on the other hand, lives almost at sea level. There he develops a fur that is just as thick because in winter,
the land here is completely covered with snow, And the summers themselves are extremely cold. This severity of the temperature, which increases as
as one approaches the pole, is easy to understand. At the equator, the rays of the sun
strike the globe perpendicularly. If we follow the rounded curve of the Earth, the more we go towards the poles, the more oblique is the impact of these solar rays, On the surface of the planet. At the poles, their effect
is therefore distributed over a larger area, And they must additionally cross a
thicker atmospheric layer. To the south of the earth, bathed by the icy waters off Cape Horn, a chain of small volcanic islands stretches, to the Antarctic continent. Archipelago at the end of the world, grandiose and desolate landscapes
from the South Sandwich Islands and the South Orkneys. Only two varieties of flowering plants can survive here. And there is no trace of a land animal. On the other hand, mosses and lichens proliferate. Some are able to survive, frozen for several weeks, Feeding on them, a menagerie of tiny animals, primitive creatures barely larger than pinheads, Resistant to the most intense cold thanks to the fact that their blood contains a kind of antifreeze that allows it to remain liquid, Even when the thermometer dips well below zero. The seas surrounding these Antarctic islands are
dotted with blocks of frozen seawater. In winter, these blocks of ice go up to
form a solid layer on the surface of the water. Icebergs are of another nature. Those are
blocks of fresh water, detached from the edge of the pack ice. Behind the pack ice, we discover the
mass of the Antarctic continent. If the soil is barren, the surrounding waters
are on the contrary particularly fertile, Thus, life proliferates on the edges of the continent
and more on the beaches of the offshore islands. This is the kingdom of fur seals and lions
of sea that feed on schools of shrimp. Their thick fur retains air and their
provides thermal insulation when swimming. The biggest, the elephant seals
have a different insulation system, Their whole body is surrounded by a thick
layer of fat that allows them, To feed in colder and deeper water. Every year, at the time of moulting, they lose this ability, They then gather on the beaches and huddle
against each other to keep warm. If you had to designate an animal that
symbolizes the icy expanses of Antarctica, You would probably choose one like this, A Macaroni Penguin or Macaroni Penguin. We are on South Georgia Island, halfway
way between Tierra del Fuego and Antarctica. In fact, it seems that originally the penguin
evolved in less cold climates. Even today, some species live
close to the Equator in the Galapagos Islands. Their very dense insulating coat of feathers, which
allowed warm swimming at all latitudes, Now serves them against the cold Antarctic winds, when standing on land or on an iceberg. They are superb swimmers. Not only are they fast
and nimble in the water, but when they come ashore, Driven by crashing waves that would crush any boat, they seem to have the elasticity of a rubber ball. These chinstrap penguins measure about 60 to 70 centimeters. The king penguin, on the other hand, measures almost a meter, a large
size is an advantage in cold climates. The bigger the body the smaller the
the skin surface compared to the volume. A large penguin therefore retains better
body heat than a little. It is in winter that the young of the emperor penguin are born, stoically planted on the ice for two months, The males, alone, incubate the eggs until
what the females return from the sea, With their stomachs filled in order to feed the newborns. Then, it is each in turn that the parents will go
down to the sea to bring food to their young. But now that winter is coming to an end,
the sea is frozen over a vast expanse, And the penguins will have to walk sometimes
80 kilometers to reach the water. Adults have a highly developed parental instinct. Those who
have lost a little one will try to adopt a stray chick, Others will even go so far as to incubate a piece of ice. As long as the chicks wear their down,
they depend entirely on the parents. Without their adult plumage, they are unable
to swim and therefore to feed themselves. Tirelessly, parents will search their own stomachs to find something to satiate their perpetually hungry little one. Week after week, they will perform their
long walk to the sea in search of food. It's only eight months after they were born
that the young will finally have their definitive plumage. Then, the whole community will go to the sea which again,
with spring and the break-up of the ice, is very close. Unlike Antarctica, which is
a continent isolated by the sea, The Arctic encompasses land areas of America, Asia, and Europe, so animals from Europe and North America, Were able to reach this frozen part of the earth,
colonize it and adapt to its particular requirements, Thus, the arctic fox, whose coat
is lighter than its southern cousin, And which turns completely white in winter. The pack ice is also the hunting ground of one
of the largest carnivores in the world, the polar bear, Who is obviously related to
its congeners in Europe and America. Its white color is obviously an adaptation
to the color of the surrounding landscape, and its size, Much larger than that of
its cousins in temperate regions, Once again depends on the fact that a large body
retains heat more easily than a small one. As we move away from the pole, the Earth
warms up enough to no longer be covered, Only partly by snow and ice. It is the tundra, a landscape of swamps,
ponds, pebbles, stones and gravel, Where life for the short time
of summer presents a surprising variety. Small flowers grow low to the ground where the wind blows
barely felt and does not disturb the effect of the sun. In shallow burrows dwell the reapers of
this meager harvest of leaves and grass, the lemmings. In the summer, when its food is plentiful, this
animal reproduces at an astonishing speed, The female can give birth to 5 to 6 young per
litter, and that 4 to 5 times in a single season. This proliferation naturally attracts
hunters like the snowy owl, A kind of owl whose lemming
is the main food. As the days lengthen, hordes of
caribou arrive from the south, Accompanied by their young born earlier in the season. They have to move constantly in order to cover their food needs and thus travel up to 25 kilometers a day. The snow geese have also arrived, some
from regions as far away as Mexico, Nearly 5,000 kilometers away, to share the rich summer relief harvest and to give birth to their young. There are two varieties. The first has feathers
dark, the second, entirely white feathers. Quickly, the Tundra is covered with their nests. The snow geese are soon attacked
by swarms of mosquitoes, Because from these warm pools hatch myriads of insects
voracious, up to 100,000 per square meter in one season. In turn, they constitute here the food
of a red-necked phalarope. Black fly larvae that have spent the whole winter
clinging to the bottom of the shallow pond are beginning to emerge. The abundance of life is now intense,
because the light is practically constant 24 hours a day. The end of August arrives, the snow goose, the first, feels the imminence of winter and resumes the path of the South. The caribou, in turn, retrace their steps
across the tundra continuing to gorge on food, To build up the fat reserve
which will allow them to survive the winter. As the weather gets colder,
the need to find shelter is more pressing, And the herds now roam
up to 40 kilometers in a single day. Finally, travelers on the way to
back will reach the first big trees. The vast coniferous forest that stretches across
southern tundra, all around the globe. It is the sanctuary that protects them from the freezing winter. The development of life requires three elements. Light, heat and humidity. The reason why trees such as these do not
grow no further north not only hold on to the cold, But also to the long dark months of winter. They wouldn't have enough light
to continue their growth. Here in northern Norway, 500 kilometers from the Arctic Circle, that light is barely enough and the cold can be extreme. Temperatures of -70 degrees have been recorded in these forests.
And in winter, there are very heavy snowfalls. Not only does the cold threaten to freeze tree sap, but
it can threaten their water supply, freezing it too. So that in winter, this region is in
somehow as parched as a desert. Pines have the same need to store their water as cacti. That's why their needles are protected
by a thick, almost impermeable skin. This skin is not edible. On the other hand, the seeds which the cones of the pines contain constitute during the winter, One of the only foods available in the forest. Thanks to a crossed beak which gave it its name, this bird
has the ability to separate the scales from the cones, To get the seeds out. Voles making their way through the snow
to tirelessly collect as many provisions as possible. Since the winter forest can only feed a few herbivores, there are also few predators. The great gray owl has particularly long legs,
designed to grab prey in the snow. She patrols for a long time because the opportunities
to feed are rather rare. The lynx has a bigger appetite and it seems capable of
calculate the yield of his hunt very precisely. Everything happens as if he knows that if he does not catch
the hare he covets over a distance of 150 meters, Well the amount of meat he would get would only be
not enough to compensate for his energy expenditure, So the lynx simply gives up. Boreal conifers grow all around the globe, forming a belt some 20,000 kilometers long, Called the taiga. From Scandinavia, it stretches across northern Europe, Siberia and to the shores of the Pacific, And further in North America. During the last ice age, when the seas were
lower, the Bering Strait did not exist, And this belt extended without
interruption to North America, This is the reason why we find
today practically the same species, In the northern regions of America, Asia and Europe. But with the arrival of spring, the forests of
each continent take on a particular character. In Scandinavia, the hawk owl, a nomad who
spent the winter in more hospitable latitudes, Remigrates north in search of food
and a place to build its nest. capercaillie or capercaillie lays
its territory from Norway to Siberia, As well as one of the only pine needle eaters, the black grouse. Owls of different species also come
in these northern forests to find their food. They don't dig their own roosts, they count
for this on the black peaks, experts in the matter. Their sharp beak with which it catches
insects also serves as scissors. However, they prefer to work the trees
dead, whose wood is considerably softer. The wood anemone is now in bloom, as are the pines. Each tree bears both male and female flowers which mature with some time lag, So that the female flowers can be
fertilized by pollen from other trees. The heat is now at its peak. The last visitors of the summer arrive and all
the northern forests resound with their songs. This fitis chiffchaff whistling so vigorously
in Scandinavia, made a long journey. It comes from the south of the Sahara, this is also the case of this wheatear. They didn't travel for nothing, food abounds here. There are myriads of insects. * This scruffy creature is hardly recognizable
because its wings are not yet unfolded. In fact, it is a butterfly, its first concern is to
leave the forest floor teeming with danger. He then pumps a fluid inside his body to inject it into the veins of his wings in order to spread them. Here the butterflies lay their eggs so that the
caterpillars can feed on young shoots. Wood ants that have missed their prey
ground will look for others on the branches. The color and shape of the caterpillars allow them
to hide from the sight of birds, However, they have no protection against
ants that hunt by smell and touch. Sawfly larvae form a swarm on pine shoots. They have a chemical defense against ants, While eating, they store part of the
resin from pine needles in a mouth pouch. When an ant attacks them, it drops a drop of this resin on its head, which damages its eyes and antennae. The ant is therefore completely disoriented. Even if she finds her way back to her nest, she will continue
to smell like other ants, Consider her an intruder and kill her. The wryneck is a member of the woodpecker family,
of which ants are the preferred prey. Like its cousins, the wryneck makes its nest in
the trunks of trees, but he does not dig them himself, He prefers to squat that of another peak. Attracted en masse by the food that
constitute the insects and to reproduce, Many of these birds will soon leave these
wood to escape the rigors of the coming winter. Some, like the redwing, will leave
to pastures further south. As for the bunting, as soon as it has completed its moult,
will fly to areas planted with beech trees. Departures to the south also for this hawk owl
threatened by the return of the cold and therefore by hunger. Beneath his route, the forest changes appearance. Rows of dark conifers give way to trees with tender green leaves, oaks, ashes, beeches, birches. * Here further south, the temperature is
milder, longer summers. These wooded areas are spared from frost, not two or three, But eight or nine months in the year. The shape of the trees is different. In place
of drooping branches bending under the snow, These spread wide with innumerable rows of leaves that help capture the abundant energy of the sun. These leaves are not covered with a skin
protective, they have fine and delicate structures, Unlike pine needles, they serve
of food enjoyed by many creatures, To large animals like deer
who consume a lot of it, But above all in much greater quantities,
they serve as food for all insects. The canopy of the forest at this late time of summer,
home to more birds than at any other time of the year. Migratory birds recently arrived from
of the north and the resident birds that gather, Food for the second brood of the season. There are also baby birds that
begin to forage for their own food. Still hesitating to determine what
is edible and what is not. Most of them go hunting
to insects and the harvest is enormous. The Treecreeper is fond of insects that live on the bark, like this poplar hornworm which tries to defend itself, By simulating ferocity. The nuthatch usually goes to market
by traversing the trunks from top to bottom, In order to spot insects that may have escaped
the treecreeper's appetite, exploring him from bottom to top. The greatest experts in the field are once again
the woodpeckers of which the Great Spotted Woodpecker is a worthy representative. His hearing is exceptional. He locates the
larvae only at the slightest noise, Which they do by moving inside the barks. Each continent has its own range of woodpeckers. There are ten species in Europe and
twice as much here in North America. This is the Sapsucker or sap-sucking woodpecker
punches holes in trees, Not to hunt insects, but to collect sap. Each hole is oriented downwards, so that the sap cannot flow outside the trunk, but inside, where it forms a small reservoir to which
feeds the sap-sucker. After summer, silence falls on the forests and the delicate foliage, unable to survive the rigors of winter, Fall to the ground after going through all
shades of red and brown. Eventually, the land is seized by frost. A lot
small mammals dug their hole to hibernate. Some, like the ground squirrel or Chipmunk, wake up from time to time in order to search for food, Where to do some exercise to warm up. In the American woods lives the most spectacular of these
sleepers, the black bear, which sleeps for months. This female won't leave her den all winter, During which she will however continue
to warm and nurse her young. In parts of the southern United States, winters are temperate enough that some broad-leaved trees, Keep this one all year round. Here also grow pines which,
paradoxically, owe their existence to fire. In the event of a fire, young oak trees burn within minutes. The terminal buds of young pines are quant
to them surrounded by a kind of tufts of needles, which burn at relatively low temperatures. By the time it burns, the main focus has moved, And at the end of the stem, the bud from which
will develop a new branch is unharmed. These fires, usually ignited by lightning, are short
duration, but they rid the forest of its dead trees. The woodpecker knows he can't dig his nest
safe than in living pines, Even though their antlers are so hard it will have to
dig for two years to build its nest. The resinous sap oozes where
the breach was opened in the tree. The birds pierce their holes very low on the trunk, there
where the sap does not flow and where the wood is thick enough, To install a sufficiently large nest. The resin flow is diverted outwards by the
drilling of channels, above and below the entrance to the nest. The nest is close to the ground. Its entrance is easily spotted because it is quickly surrounded by a yellow layer of coagulated resin. The rat snake is a large predator.
He is an extremely skilled climber. The fact that the opening of the woodpecker's nest is quite low
and therefore relatively easy to reach by the snake, Seems to expose nest-dwellers to considerable danger. But the real function of the
resin will now appear to you. * The chemical components of this resin irritate
the serpent's skin and force it to arch itself, To move away from the trunk until the fall. Damage from fires can often be
found in southern and Californian pine forests. This tree is twelve meters wide at the base and 80 meters high. It is a giant sequoia that is estimated to be 2500 years old. This other sequoia, baptized General Sherman, is slightly
bigger. Its weight is estimated at nearly 1400 tons. It is the heaviest living organism in the world.
It is believed to be between 3500 and 4000 years old. And the redwoods grew in America
of the North during the Ice Age. But 8000 years ago, when the Earth
began to warm up, they disappeared, Except for a few isolated groups in the snow-capped Sierra Nevada Mountains for nearly six months of the year. Conifers owe much of their proliferation to their ability to adapt to changing northern climates. They can survive dark and frosty days just as well
of winter than to the heat and raging fires of summer. If we go lower to the south, to 1600
kilometers from here, we arrive in the tropics, Where the climate is radically different. More true variations, but a constant level
of light, rain and heat throughout the year. * It's the force of gravity that keeps around
the Earth the clouds and the air in which they float. The impalpable and invisible air, at this point
omnipresent that we end up forgetting its existence. The air without which yet the seeds
and insects, birds and men, Would be unable to tear themselves away from Earth's attraction. Dandelion seeds float because
the slightest breath of wind can lift them, And they fall back very slowly because their
corolla holds air like a parachute. This is how she crosses the vastest oceans
to land on the most distant islands. Pollen seeds are so small that the presence of
down is not necessary to keep them in the air. The microscopic unevenness of their surface is sufficient. The spores expelled by puffball are even smaller. The slightest breath scatters them around
by the tens of millions like smoke. The tangle or Virgin's thread, which sometimes covers
meadows, is the animal equivalent of fluffy seeds. It is produced by thousands of small spiders. As soon as they are born, these spiders climb to the top
grass stalks or on small piles of gravel. They point their abdomen upwards and away from their
spinneret glands, they produce a very fine silk thread. As it lengthens, the wind carries it. At some point, the little spider turns around. She grabs the wire with her forepaws and lets herself be carried away by it. Only the smallest and lightest animals and
plants can defy the laws of gravity in this way. Many seeds are too heavy to be so
carried by the wind, even if they are very fluffy. On the other hand, those produced at the top of a tree
high can instead exploit gravity. These seeds, which grow in the jungle of Venezuela,
have fins designed in such a way that, When they fall from the tree, they spin.
Their descent is slowed down and the wind can carry them away, Some distance from the tree they come from. Some animals, like this Southeastern flying gecko
Asian, can achieve a comparable result, Thanks to webbed toes that allow them
to cushion the speed of their fall. In the same forest, another lizard managed to hover too,
by stretching real wings of skin from its sides. But the champion of this exercise is this flying squirrel whose enormous coat of hanging skin constitutes a veritable parachute. In horizontal flight, it can even do better. Just as it happens on the wing of an airplane when
the air attacks the front edge of his taut mantle, The pressure is reduced on the upper surface of
this one and the squirrel can then rise slightly. All of these hovering creatures can control their direction, but they are generally unable to propel themselves very high. Paradoxically, it is closer to the ground,
in tall grass vegetation, That we find creatures that have
real flight skills. The most demanding movement is take-off. The insect must rise in the air
just by the strength of his muscles. By a circular sweep of its wings, it rapidly increases
the pressure under him and thus finds himself sucked upwards. Larger insects such as grasshoppers, accentuate
this effect by a powerful leap when leaving the ground. The flight of birds, much heavier,
requires even more energy. Birds also use their muscular legs to relieve the work of their wings. They jump, they soar through the air. The tallest birds to take off must rise
the speed of the air current over their wings. They cannot fly away without taking
speed while leaning on the ground or on the water, Exactly as an airplane does on takeoff. Once in the air, flying animals of all kinds enter a completely different environment and they exploit it to the fullest. The damselflies find their food in the area.
They mate there and even fight there. This sphinx lays its eggs on the flowers while
flying because it is too heavy to land on. It also feeds while hovering in front of the
flower from which it sucks the nectar with a filiform proboscis. This hummingbird, Helen's calypt, is
even smaller than the Sphinx, He has the same ability to flap his wings up to 80 times.
per second to stay in the air almost motionless, While he drinks from the chalice of flowers. * The wings of birds are better adapted than those of
insects, because their feathers fit ideally, Easily slide over each other, allowing
to vary the shape and surface of its wings. They can thus extend widely when lowering, then, during the upward movement, Shrink to provide less air resistance. The reduction in air pressure on the surface of the wings, which facilitates elevation, can be clearly observed at idle, Because it has the effect of sucking the little feathers up. The albatross is an expert in the art of soaring
relying on the updrafts. Again, the reduction in pressure produced when
the air passes over the spread wings of the bird, Causes feathers to ruffle. When it must travel against the wind, the albatross descends close to the surface of the water, as the waves lessen the force of the breeze. The cliffs are favorite places for gliders like the Albatross. They deflect the sea wind upwards, And thus allow the birds to take off easily or
to hang in the air for hours, In its updrafts. The heat can also allow to rise in the air. In a hot air balloon, this heat is produced by
gaslights and the rising air is so powerful, That it allows to carry towards the sky a
heavy basket and several passengers. We are in Africa and we are heading towards
the great game plains of the Serengeti. As the sun warms the earth, other currents of hot air naturally form over the boulders, Or bare slopes which, rather than absorbing
the sun's rays reflect them. This thermal lift is
particularly appreciated by vultures. These large birds have wings to match. Hard to put in motion. In the morning the birds just flit from a tree
down to each other, they wait for the earth to warm up. Now a vulture is coming to join us. A rock it is flush with is heating up in the sun. The air above him will rise and that's exactly what
needed by the vulture to fly away easily. The vultures climb ever higher, using the
thermal currents to effortlessly scan the plain, Where parade the largest concentration of cattle in the world. Before nightfall, at least one wildebeest will have been the victim of predators. The vultures have now taken flight. At several hundred meters of altitude they can
quickly detect the presence of a dead animal. If so, they dive to the ground, as soon as a bird
spotted a carcass, dozens more are coming. These are medium-sized vultures,
Rüppell's vultures or white-backed vultures. But among them is one of the greatest
African vultures, the Nubian vulture. In these African mountains as in some others in Asia
and Europe, lives a species of vulture, the bearded vulture, Who has a very particular mode of food. It feeds not only on marrow, but on the bones themselves. And for that, he uses a unique technique. He
first carries his bones to a real workshop. It's a bare rock. The bird chooses it close to the edge of the cliff. Thus, the vulture will be able to fly away more easily
if he has to carry a very heavy bone. Now all he has to do is gain altitude
and drop his burden on the rock anvil, Where it will break into small pieces. Some large crows proceed in the same way,
but generally with much less discernment, As for the choice of land. Now, all that remains for the bearded vulture is to consume its meal. Owls also have very strong wings.
developed. But for another reason. Their high lift allows the owl to
not having to beat them loudly. And this is vital for an animal which, if it wants to reach its nocturnal prey, must approach them in the greatest silence. Its feathers are even lined with a very soft down
which acts as a sort of silencer for them. Although owls hunt after dark,
they orient themselves thanks to the great acuity of their sight. And their silent flight allows them to detect the slightest
screeching sound indicating the presence of voles or mice. When the nights are pitch black, even a
however, the owl cannot orient itself there, those nights belong to bats alone. They are able to navigate in the dark
total. It has a kind of natural sonar. She screams in the ultrasonic range and
is guided by the echoes which come to them in return. They are skilful, to the point of swallowing a fly in mid-flight. Birds have such mastery of the air and such
ability to remain airborne for entire days, That they have become the greatest travelers in the animal world. Above Panama, in October and November,
impressive clouds can be observed. The falcons and the vultures, aura or cathars, fleeing the arrival of winter, fly away for a stay of a few months further south. As the weather gets warmer, they find the thermal currents that allow them to reach altitude, Necessary to perform their flight with minimal effort. Birds are not the only ones to accomplish these immense
intercontinental routes. As incredible as it seems, Very frail looking creatures can make it
as much. Insects thus fly away with a tenacious will, On the trail of the most enduring migratory birds. These monarch butterflies were born in
autumn in the woods of North America. They have just arrived in Mexico City after an extraordinary journey of more than 3000 kilometers. They will rest here for a few months, Then they will make the return trip,
feeding and mating in flight. Finally, some will join the woods of their birth. Thus, the Earth is flown over by routes of migrating animals. In the Americas, most transit through Panama, although
a few daring choose the Caribbean stage. These journeys can reach thousands of kilometres. The atmospheric envelope does not have
only eight kilometers thick. It is an altitude that can be reached by hot air balloon, better equipped however than that used previously in Africa, Because at this height, a system
oxygen supply is required. Now we're very close to the limits
of this atmosphere that envelops the planet. It is at this altitude that occur that
weather variations are determined. The weather on the surface of the
Earth plays out here in the upper atmosphere. Water molecules evaporating from the surface of
seas and lakes by the heat of the sun, As well as those produced by plants under
form of vapour, rise from the surface of the earth, And at the same time cool, condense
to form clouds of droplets. Moved by the winds, these clouds evaporate and re-condense, form and reform. The greatest atmospheric disturbances
are due to gigantic thermal currents, Caused by the Sun in a sky full of humidity. Water molecules inside clouds condenses
to form larger and larger droplets. The air rises quickly and keeps them
suspended inside the clouds. Eventually, their weight drags them
in the form of torrential rain. A storm such as this can bring death and destruction. It can also bring life because the rains it generates are distilled by the sun from the surface of the oceans. These rains are therefore made up of fresh unsalted water, essential to any form of existence on Earth. These freshwater sources are not
than the prelude to a long journey. Located in the heights of the Andes, they will lead, with countless others, to the longest river on earth, The Amazon. Swollen with dust, rocks and mud, they
are already rich in nutrients. They hurtle down the slopes at an impressive speed. And all the creatures that live there
have to swim perfectly. This is the case of the Armed Merganettes or Duck of the Torrents. These birds exploit the eddies and
the whirlwinds with consummate skill, Paddling powerfully with their webbed feet. They go up
the stream. They anchor themselves to the rock with their tail, And, to ensure their grip, use small
horny spurs located at the joint of their wings. But what is there to eat in these cold and tumultuous waters? There is foam there, as in all the waterways of the world. A moss that provides shelter to
a multitude of larvae, insects. In the summer, these creatures will come briefly
fly over the river to mate. But most of their lives will be spent underwater. Some are literally contoured to withstand the current. The larvae of the phyganes shelter in protective tubes,
the hollow of a reed or a construction of wood debris. By building their shelter from heavy grains of sand. Some ballast themselves so that the current does not carry them away. The blackfly larva stays at
a pebble by a sort of hook. Even if she loses her grip, all is not lost. A silken thread, a sort of line of
survival, connects it to its attachment. Going up this thread, she regains her
port to secure a new hold. Through its spinneret gland, it unrolls a tampon of
very fine silk to which it moors again. The simulator has developed modified antennas, so
of net with which they capture its food. The small streams that descend the slopes of the valley to feed the nascent rivers have their own population. In Malaysia, big-headed turtles
or platysternon are aquatic. They go up the waterfalls using
of their very long tail as a point of support. In these other falls in West Africa and nowhere else lives the extraordinary hairy frog. The hairs in question are actually
filaments implanted on its sides, And which serve as gills to absorb oxygen from the water. Other unusual appendages, its claws
which help it to cling to the stones. Falling from a height of fifteen hundred meters,
the innumerable springs that feed the Amazon, Join the brown waters of a real
tributary, thickened by mud and sediment. The flow of the torrent carrying sand and gravel
now carve the sides of the mountain. When the current collides with a harder rock,
like an ancient basalt flow, Its progress is temporarily thwarted.
It goes over the barrier in a spike. This is how the most beautiful waterfalls are formed, such as the Iguazu Falls on the borders of Brazil, Paraguay and Argentina. At the base, the flow hits the rocks until they split, so the falls make their way downstream, Leaving deep gorges upstream. Animals live here, inside the falls itself, like these swifts that nest on the rock face behind the waterfall. Every day they gather very
high above the Iguazu River. After a game of insect hunting, they join
their nest by springing through the aquatic screen, Who will protect them for the night. And the river recedes, leaving behind
its mountainous sources. His appearance has changed. These waters are enriched with nutrients. Along the Amazon, the jungle thickens. birds like
the Sun Caurale wander in search of food. Huge fish cross in the
slower flowing waters. The Arapaima, one of the largest water fish
gentle. They measure almost two meters. The Amazon contains nearly 3000 different species of fish. The catfish stay at the bottom of the river. Their sensitive antennae allow them to spawn
a path through the muddiest bottoms. Some of them are able to defend themselves by unloading
electricity, others have ventral suction cups, Or ridges that allow them to cling to rocks. In South America alone, there are 1200
different species of these catfish. In these crowded waters, many fish offer
their offspring special protection. This one, the discus, goes further. It provides its young with a special menu, a special viscous secretion that it produces on its sides, And what they feed on. The more the river evolves, the more it slows down its
Classes. The slightest obstacle is enough to slow him down. Outside each curve, the flow erodes the shore at
the inside of the curve, where the current is slower, Water deposits its sediment load. Thus, with the passage of time, the curves of the
river approach each other. Over the years, they take the shortest route.
The lands that separate them eventually crumble, The river shortens its course. Over time, some meanders become
lakes quickly overgrown with vegetation. These leaves are those of the famous Victoria
regia, the giant water lily of the Amazon. An aggressive aquatic plant that thrives in
detriment of those, more modest ones which surround it. Initially, these leaves are the size of a soup plate.
In a few days, they reach two meters in diameter, That is a growth of some three square centimeters per minute. Their air-filled ribs make them bear the
weight of heavy aquatic birds, such as the jacana. Which pastes with widely spread fingers allow you to move on much less resistant leaves. It feeds on insects and it is spoiled for choice here. This hydrometer is installed on a sheet, but it could also be installed comfortably on the surface of the water, Because this constitutes a completely
likely to support small creatures. The water molecules are bound together by a cohesive force which creates a relatively firm surface tension. The hydrometer pierces its victim and feeds on its substance. The tension film that forms on the surface of
water not only serves as a platform for insects, It also constitutes a sounding board which
allows them to detect the approach of a prey, To make warning signs or to launch messages of seduction. The notonect like the hydrometer patrols the surface,
in search of a prey, but underwater that one. Thus, these two insects share most of this
who may be trapped on this aquatic film. This beetle, which lives on plants
riverbanks, has a few diverse talents. It evolves on the surface of the water with particular agility. It is also able to produce a substance
which propels it at an accelerated speed. Finally, among other performances and like most
beetles, it is even able to fly. The Amazon carries a mass of ochre-coloured sediments from
its sources in the Andes to its junction with the Rio Negro, Which, him, carries only waters without silt, only tinted
black or green by dissolved organic substances, For he descends from the Northwest where the lands are
made up of hard, bare rocks. For several kilometres, the two rivers
do not mix their waters which abound with food, And life on the banks is flourishing. hordes of
giant rodents, the Capybaras or Cabiaï, thrive there. These amphibian animals are excellent
swimmers. Their feet are webbed, Their eyes, ears and nostrils are
all located on the top of their head, This allows them, when they enter the water, to continue to see, hear and smell what surrounds them on the surface. Giant otters have similar physical characteristics. This Amazonian species breaks all size records. Some specimens reach almost two meters in length. This is a large family represented in
many rivers around the world. A multitude of birds, also claims
his share of fishing in the river. Here is a crowned merganser. It is a species related to
ducks whose long, narrow beaks are lined with notches, And tailor-made to catch the
fish with slippery scales. In the final phase of their journey, these great
rivers often no longer control their course. Their distant tributaries, storm-soaked mountains, pour huge amounts of water that cause them to overflow. Every year, the Amazon experiences floods that inundate
tens of thousands of square kilometers of forest, And which make him reach in some
places twelve meters deep. The first to benefit from these floods are obviously the fish which draw treasures of additional food there. Arriving at the end of their race to the sea, the rivers end
to deposit the sands and muds which they carried, For hundreds, thousands of kilometres. There, aquatic plants and fish proliferate, attracting flocks of birds like those snow geese in northern Canada, Or those other geese on the other side of the world, in
a tropical delta in Papua New Guinea. The Amazon delta is immense,
spread over more than 300 kilometers. Through this maze are three quarters of the waters
rivers of the globe that will eventually join the ocean. It is an intermediate aquatic world, neither really soft,
nor really salty, where the waves come and go, Where land and water are in constant motion. A world at the borders of which the Moon,
describing its orbit around the Earth, Causes high ocean tides twice a day. As it erodes the coasts, the sea
deposits masses of debris on the beaches, Which on the contrary cause an advance of the earth. In the tropics, mangroves grow at the foot of
the ocean, gather mud around their roots, And thus create new territories, the mangroves. Wherever it is like here in the estuary of a river
English, when fresh water meets sea water, It deposits sediments filled with food
which immediately attract new inhabitants. This small crustacean, the corophium, measures about one cm.
It feeds on bacteria which proliferate by millions, Breaking up the organic substances that rot in the mud. The Nérisses are worms that live
in holes. They attack corophium, Feed on algae, bacteria, virtually
everything that moves around them. On the ponds floats a mucus produced by shells in the shape of arrowheads, no larger than grains of wheat. The mucus attracts the bacteria and the shellfish eat it all up. Sheltered in its tube La Sabelle, a kind of worm too, spreads its tentacles to catch organic particles, Slowly falling to the bottom. The filaments of the fan are in continual movement in order to
to bring the particles down towards the oral orifice, Located in the center of this kind of tube. At the same time
that she feeds, she ejects a cement of mud, And mucus that consolidates the edge of the tube. The hull rests on the bottom with its shell gaping open. It filters the water by sucking it through a
siphon and pushing it through another. Mussels use the same technique to harvest
inside their shell nutrient particles. The tide, as it recedes, exposes certain shells. Thousands are sometimes gathered in an area of one square meter. All these mud eaters constitute a
very rich catch and amateurs abound. Migrating sandpipers are a delight and waders come to the estuaries to feed all year round. The Godwit benefits from large legs and
a long beak that allows it to evolve, And to feed in water several centimeters deep. The curlew prefers to work in the dry. Its slender beak allows it
to probe deep into the mud to catch worms. Dunlin, the smallest, seeks
catches to his measure, insect larvae. The plover has only a very small beak and cannot
grasp only food floating on the surface. In general, it works solitary so that its prey
is not alerted by further paw trampling. As for the avocet, it is by a mowing movement of its curved beak that it catches the creatures living in the liquid mud. As the rivers bring in new sediments,
swamps increase in width and depth, Developing on their surface a silty crust of microscopic algae which begins the process of consolidation. Quickly, taller plants y
implant their roots, like glasswort. * Then the process speeds up. The rising tide
brings new mud particles, Which accumulate around the stems of glasswort
and which will not leave with the reflux. Thus, at each tide, the swamps
thrive deeper and deeper. Glasswort grows in estuaries
cold from Europe to the tropics. End colonizers are not small plants
but real trees, the mangroves, Of which there are now about forty different species. The flowers of these mangroves are pollinated by the wind. The seed does not immediately leave its
original tree, it begins its development there, By producing a green shoot of about thirty
centimeters with a tapered end. If it falls at high tide, it floats horizontally
and can travel for miles before running aground. If it falls at low tide, it gets stuck in the
mud and the return of the waters landais will not lodge. Quickly, she develops downward ridiculousness,
leaves up and within a few days, It is firmly installed. Even if it does not seem obvious, Periophthalmus
is a fish. There are several species, This one lives near the high tide lines and
it spends most of its time out of the water. He must keep his skin moist because
it is through it that it absorbs oxygen. It also keeps the mouth full of water
to feed its gills from time to time. It feeds on small crabs that it finds in the mud. Another species lives near low tide lines and
only spends an hour or two out of the water a day. She sifts liquid mud in search
worms and small crustaceans. A third species, finally the most common and which is vegetarian, feeds on algae and other microscopic plants. They protect their territory with
force by surrounding it with fortifications. And this to form a patchwork of compartmentalized reservoirs. These flat and shallow apartments impose on Periophthalmos, Curious gymnastics at the time of the love quest. Finally, evil succeeded in convincing a
female to join him in his private pool. He can continue to do his
court in a more conventional way. Around the roots of mangroves, calling crabs
or fiddler crabs are in full swing. The females scoop up mud with their
two tongs and the lamb's lettuce at a hellish pace. The males consume the same quantity, but they
only have one claw to harvest it. The other is so developed that it
is useless in their chewing exercises. In fact, it only serves them to signal to females
of passage to encourage them to follow them in their holes. When you have a little time, stop
you chew mud and don't go see me. At low tide, there is no shortage of food around the mangroves. Terns hunt fish, easier to
catch now that the waters are shallower. Kingfishers, on the other hand, make a
large consumption of decoy crabs. With the rising tide come new schools of fish. Fish hungry for what the river
could have dropped off at low tide. In the swamps of Southeast Asia, the
toxote or archer fish, feeds on insects. He has his own way of catching them. With a quick lick, he sends them a jet
droplets, like a water gun. Stunned, the insect falls to the surface of
the water or the native hastens to swallow it. Where the earth sinks into the waters in a peak.
The area between the marshes is obviously much smaller. The creatures that live there are
constantly prey to two dangers. At the high tide line there is the risk
to wash up on the ground and dry out. And at the low tide line, there is the risk of getting
get caught by animals coming from the depths. Each species living on this narrow terrain develops
strengths that allow him to compensate for his weak points. Some, which can only endure a brief stay in the open air, live at the lowest possible level, such as the sea urchin, which feeds on algae. Out of the water, there is no other solution
than to cling temporarily to the rock. That's what these giant sea anemones do too.
who fold their tentacles because in the open air, They do not catch anything to eat and the sea squirts do not
can filter water and feed only occasionally. Starfish are carnivorous.
These feed on mussels. They cover them with their arms equipped with small suction cups
and slowly force their shells to devour them. Below the low tide line. No mold resists it. But like many creatures in this area, Once out of the water, the stars
sea are powerless to feed. Mussels therefore choose to settle on rocks
alternately exposed to the waves and to the open air. Mussels cannot withstand very violent waves. In the most exposed places. They are replaced by barnacles, small fixed crustaceans which have greater resistance. Thus, each part of the bank is invaded by
organisms best adapted to these combinations, Very accurate physical and biological conditions. The incessant movement of the sea ends up reducing the rocks of the coast to sand that the waves will deposit at the edge of the sheltered bays. Here live other intermediate communities. Only a few venture
above the high tide line. This is the case of turtles that are there
constraints, in a way by atavism. This one is a Pacific Lepidochelys.
With its 60, 70 centimeters long, She is arguably the smallest sea turtle. Like all its congeners, it descends from terrestrial reptiles and its eggs can still only develop in the open air. After mating at sea, she
therefore lands on the coast to lay eggs. In Costa Rica, this landing resembles a
real invasion at the rate of 5000 turtles per hour, And only on two or three beaches that they
are chosen from among the hundreds in the region. Even more surprisingly, they do not invade the
beaches only during certain nights, in August and November. If their fins are effective at sea, at
soil they are only of poor use to them. They are barely able to drag them on the sand. This massive and sporadic spawning is a protection for
the eggs, which are thus less threatened by predators. Each female lays a hundred eggs
for unknown reasons, Rarely more than one of these 100 eggs will produce a
little one who will then return to the sea. On other beaches, more discreetly, other
very different turtles have begun to lay their eggs. These are the largest of all
sea turtles. These are the splendid leatherback turtles. The leatherback turtle is a very mysterious animal.
He is a solitary wanderer of the oceans. They are found in virtually all tropical areas and others have been reported far away, in Argentina, In the British Isles or in North America. We know very little about her, except that she
feeds on sea urchins and fish. But she is also very fond of jellyfish. We
ignores the average lifespan of leatherback turtles. Nothing is known of their mating habits.
It is also not known how the females orient themselves, To find their traditional nesting site. In fact, until 30 years ago, we had never discovered any. The reproduction of these behemoths remained a complete mystery. Since then, we have spotted some of the beaches where
they lay on the coast of Suriname, South America, And here on the east coast of Malaysia. * The local populations, of course, were aware
of their presence and they plundered their eggs. It is a practice that has not disappeared, unfortunately, on the contrary. Today, turtle eggs are plundered all the more. This endangers the very survival of
this enormous and extraordinary creature. But maybe the leatherback turtle has
fortunately unknown spawning grounds, On one or the other lost coral island
in the ocean, out of human reach. If you want to discover an island at the end of the world,
why not this one? Aldabra, in the Indian Ocean, The nearest land is Africa, 400
kilometers to the west. It's actually a group of islands, Which are part of the old continent
of Gondwana, now submerged. This one is anatol on top of a volcano
extinct sprung from the sea 50,000 years ago. It has now become the home of thousands of seabirds, such as its frigates which have flown for countless kilometres, To come and rest on the mangroves
that grow along the coast. Most of the surrounding plants must have come
on the surface of the water in the form of seeds. A coconut can float for
more than four months before dying. This one is very much alive and nothing would prevent it
to grow along the edge of the beach. As they grow, the coconut palms bow their heads overhead
the sea. So the nuts fall into the water and at high tide, They leave to colonize other islands. The most famous inhabitant of Aldabra, here it is, it is a
giant tortoise. Most turtles float naturally. If one of them, feeding on a mangrove
from the African coast, had just been washed away by the sea, It could survive long enough to be carried by currents to these islands in the Indian Ocean and develop there. It is certainly in this way that the
ancestors of the Aldabra giant tortoises arrived here. Life on this island is tough. The tropical sun
hitting animals, threatening to literally cook them, Inside their shell and the traces
Such accidents are common. When the heat increases, the turtles go in search
some shelter likely to provide them with shade. Here and there, on some beaches swept by
the wind, grow a few groves which, at noon, Are crowded with groups of turtles who have come to take refuge
there waiting for a little freshness to return, Which will allow them to set off again in search
edible leaves constituting their meal. It has therefore been 50 millennia since Aldabra emerged. In terms of evolution, this is not a considerable duration. It is sufficient, however, to make changes, The physical characteristics of animals
who live here in isolation. They have changed from their ancestors
who colonized the island, but they are also different, Of their current close cousins all over the world. Several species of birds have thus undergone changes, sometimes slight, but which now make them unique in their kind. Everywhere else, the Sacred Ibis has eyes
dark, here they are light blue. The Aldabra kestrel is smaller than that
of Madagascar and the Souimanga or nectarine of the island, Has darker plumage than its African relatives. Island reptiles seem to have a
tendency to gigantism, like the Aldabra tortoise. Another famous large format lives on the island of Komodo,
in Indonesia. It is the largest lizard in the world. Known as the Giant Monitor Lizard or Komodo Dragon. It is not difficult to meet them. It only takes one
goat carcass, preferably in a state of decomposition. Its smell will attract them from miles around. It was once thought that these animals were exclusively scavengers, that they fed only on carrion. We now know that they can turn into active killers. They attack and they kill the goats,
buffaloes and even occasionally man. If I can approach them without too much risk, it's because they
have very poor eyesight and are practically deaf. They make up for this with good olfactory and taste qualities. So hopefully the smell of those dead goats will be stronger than mine and they won't be interested in me. They are actually the kings of this island
of which they are the biggest predators. There's no animal here they could prey on
nor any who can dispute their food. This is no doubt what, in their isolation,
allowed them to grow to such a size. They can measure up to three meters and weigh
about fifty kilos, and even more. * Komodo is not, like Aldabra, an atoll which
developed from the flooded summit of a volcano, But the eroded remains of a much larger volcano that
raised hundreds of meters above sea level. Volcanoes are indeed the origin of most isolated islands and the Hawaiian Islands themselves are all volcanic, The largest and newest of
they are still erupting. On these high islands accumulate clouds laden with humidity. On their sides, exposed to the wind, the rain falls heavily. Streams rush down the sides of the mountains, crossing loose layers of ash, eroding deep valleys. Thus, unlike the atolls which constitute
a platform of coral and sand and rocks, Rising only a few centimeters above the
sea level, these immense volcanic islands of Hawaii, Offer a wide variety of habitats to their colonizers. From the high cold slopes covered in ash to the
well irrigated, hot and humid low valleys. There, recent and smooth basalt, further on, ancient
forests growing on ancient lava flows. To exploit all this, the colonizing elements
have taken many forms. The Palila is part of a big family
of Hawaiian nectarivorous birds, the drepanids. Their ancestors were probably finches transported
here thousands of years ago by heavy storms. On site, they developed more than 30 species, each
with its particular diet and habitat. The palila feeds on seeds. He owns,
to break them, a short and powerful beak. La Maki is one of its parents. His body is similar but
its beak is thinner, suitable for catching small insects, And to suck the nectar from the flowers. Some species have shimmering plumages
which distinguish the male from the female. It does not interbreed with related species,
so that they become more and more specific. Thus the red-headed Papane, very showy, with a large beak
suitable for its diet, which is almost exclusively made up of nectar. *, which has a small crest of white feathers at the base of the beak, has a mixed diet of nectar and insects. Vermilion Lishui has a long, curved beak, which allows it
to probe deeply into the trumpet-shaped flowers. The most endearing, finally, is undoubtedly **** with its splendid double-function beak, the lower mandible stings, And spreads the bark to dislodge the insects, The elongated upper mandible is used to extract them. He uses both with rare dexterity. Human beings landed in Hawaii about fifteen hundred years ago, and they were Polynesians, remarkable sailors. They sailed the ocean in float canoes
can carry several hundred passengers, And whose size was twice that of the canoes
still used today in the Pacific. From their base in Samoa, reached by their
ancestors more than 1000 years before our era, They colonized the islands one after the other,
to Hawaii in the north and to Easter Island in the east. But their greatest journey, they made it to the south, traveling 6500 kilometers of ocean to reach New Zealand. When they arrived 1500 years ago, the land they discovered
there was very different from where they came from, With mountain ranges and inextricable forests containing many more animals and plants than the coral atolls. Because this land was once part of a larger continent populated by the ancestors of its current inhabitants. Here is one. The tuatara or sphenodon, a nocturnal reptile with a functional third eye that feeds on earthworms and insects. He looks like a lizard, but he's
rather related to dinosaurs. Elsewhere, its species has long since become extinct. Another relic of this disappeared continent is the kiwi. The kiwi has no visible wings or tail, and it lives
in a hole at the bottom of which it lays a huge egg. Largest, in proportion to size in birds. Its long floating feathers do not allow it to fly. With his shaggy look, when he runs quietly
on the ground in search of food, It is rather reminiscent of a mammal. And indeed, he acted a bit like a mammal
in these islands where originally there were none. If its beak resembles it to birds, the
kiwi uses it in a weird way. He sinks it deep in the earth to smell the worms
on which it feeds, as a mammal would. Since New Zealand became, there has been
a few million years ago, this group of isolated islands, More recent birds have appeared there, such as this
species of pigeon, the Kereru, or this parrot, the kea. His ancestors came from Australia. He adapted to
the cold life of the high mountains where it feeds on berries, Roots and insects, but also carrion like a crow. Living on this island has subjected
this other parrot, the kakapo, a profound mutation. There are no mammals on this earth that eat
leaves. This bird has made it its essential diet. This extremely nervous nocturnal animal lives
indeed of the vegetation that surrounds it. It is particularly characteristic
animals that inhabit the island. His only defense is to stop as he
do the. He does not move and waits for the danger to pass. The kakapo is also a giant. It is the biggest of
all parrots. It can weigh more than three kilos. And this weight, this large size are to
the origin of a third characteristic. Of all the animals on the island, this one is one of the most vulnerable. * The kakapo's troubles began when
the Polynesians arrived and chased him away. They had brought with them a kind of rat which devastated the nests. When, centuries later, Europeans landed, they introduced other killers, the ermine and the cat, to the island. Today, only a few dozen kakapo remain. Countless predators were imported here from
Australian polecats and opossums as pets. Rabbits from Europe for their flesh and their fur,
and even deer for hunting pleasures. All have had a devastating effect on the environment, ranging
even sometimes by ridding the earth of these plants, Until it causes severe soil erosion. As long as man continues, as in New Zealand,
not to act as an active protector of nature, These strange animals will be doomed, as
were their now extinct ancestors, As was the Dodo of Mauritius,
exterminated by other men. The creatures you find on these islands
don't necessarily spend all their time here. Some, like those tireless travelers
are the madmen come there only to rest. Like frigatebirds and many other seabirds, they find their food not on the islands where they nest, But in the sea where another proliferates
complex community of plants and animals.
