Il existe une mystérieuse frontière invisible dans la nature que aucun animal ne franchit jamais, et les scientifiques essaient toujours de comprendre pourquoi. Ce n'est ni un mur, ni une clôture, ni quoi que ce soit construit par les humains—c'est juste là, comme un champ de force invisible. Certains chercheurs pensent que cela pourrait être lié à des choses telles que les champs magnétiques, les marqueurs de scent ou même des instincts transmis à travers les générations. Les animaux d'un côté restent sur place, et ceux de l'autre ne les traversent jamais, presque comme s'ils savaient quelque chose que nous ignorons. C'est l'une de ces étranges énigmes naturelles qui vous fait vous demander ce qui se passe d'autre dans le règne animal. Vous voulez en savoir plus ? Restez dans les parages, car celle-ci est étonnante ! Animation créée par Sympa.
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Musique par Epidemic Sound https://www.epidemicsound.com
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Nos réseaux sociaux :
Facebook: https://www.facebook.com/sympasympacom/
Instagram: https://www.instagram.com/sympa.officiel/
Stock de fichiers (photos, vidéos et autres):
https://www.depositphotos.com
https://www.shutterstock.com
https://www.eastnews.ru
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Si tu en veux encore plus, fais un tour ici:
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FunTranscript
00:00This invisible border divides the world into two distinct regions and, for unknown reasons,
00:06the majority of animals, fish and birds cannot cross it.
00:10Called the Wallace Line, it marks a separation between Australia and Asia.
00:15This name comes from Alfred Russel Wallace, a British explorer and scientist who identified it in 1859.
00:23He had gone to Asia to study the Malay archipelago, also known as Insulind.
00:29During his explorations through the jungles, the hills and by sailing,
00:34Wallace noticed a kind of invisible barrier.
00:38In the West, in regions such as Borneo and Sumatra, he observed typically Asian species,
00:44large rhinoceros grazing on foliage and monkeys skillfully swinging from tree to tree.
00:51These luxurious forests were full of animals that were willingly associated with the jungle.
00:57However, when he crossed this imaginary line and reached Celebes or Lombok,
01:02he met rather animals similar to those of Australia, as well as exotic birds such as cacatoes.
01:10The behavior of animals varies from one place to another on the Wallace Line.
01:14Some species excel in crossing natural obstacles, such as water streams, while others are less suitable.
01:21For example, bats, able to fly over water, sometimes cross this line.
01:27Conversely, large terrestrial animals, such as elephants, are generally confined to one side.
01:34Some birds, more fearful, prefer to hide in dense bushes and trees to escape predators,
01:41thus avoiding to venture over large expanses of water without shelter.
01:45Plants do not follow the Wallace Line as strictly as animals,
01:49because they disperse according to specific mechanisms, such as seeds transported by wind, water or animals.
01:57The eucalyptus species, for example, remains mostly on the Australian side.
02:02However, the rainbow eucalyptus has managed to implant itself in the Philippines, on the Asian side.
02:08Underwater, the Wallace Line is of little importance.
02:13The region located between this line and Australia, nicknamed the Coral Triangle, is a true explosion of marine life.
02:20Now, after more than 150 years, scientists think they have finally elucidated the mystery of the Wallace Line.
02:28They estimate that everything goes back to about 35 million years ago,
02:32when Australia separated from Antarctica and gradually drifted to collide with Asia.
02:39This shock would have led to the formation of an island chain, which is none other than the Malay Archipelago, located between the two continents.
02:46These upheavals have led to significant climate changes, which have profoundly influenced the animal species living in the region.
02:54Researchers have used a computer model to simulate the behaviors of more than 20,000 species on both sides of the line, several million years ago.
03:04When Australia moved away from Antarctica, a vast expanse of deep oceans opened up around this continent,
03:11giving birth to the largest ocean current in the world, the Antarctic Circumpolar Current.
03:19This turbulent current has cooled the global climate, completely changing the living conditions of the different animal species.
03:26However, these effects were not universal.
03:30Indonesia, which remained warm and humid, was an ideal environment for Asian species, which could migrate from island to island to Australia.
03:41On the other hand, Australian species, adapted for millions of years to drier and fresher habitats, had more trouble adapting to tropical conditions.
03:52Scientists believe that understanding the adaptation of species to these major climate changes several million years ago
03:59could help us predict how current species will react to similar situations.
04:06Other scientists have also tried to describe and explain the invisible natural border between Asia and Australia,
04:13after the work of Wallace, by drawing their own lines.
04:17The Sclater Line, in 1894, the Lidecker Line, in 1896, the Pelsener Zoological Limit, also called the Weber Line, as early as 1904, and the Meagher Zoological Limit, in 1944.
04:35The Weber Line, for example, differs slightly from the Wallace Line, separating the eastern and australian fauna regions within the Wallacea.
04:43This group of islands, mainly Indonesian, is isolated from the Asian and Australian continental plateaus by deep detroits.
04:50As they have never been connected to the continent by land, only animals capable of swimming, flying or floating have been able to reach them,
05:00thus explaining the unique diversity of their fauna, of both Asian and Australian origin.
05:06The Weber Line marks the tipping point.
05:09On the one hand, most animals come from Asia, on the other, they are mostly Australian.
05:15Another major migratory event in the history of the Earth took place on the American continent.
05:21About 30 million years ago, South America became an isolated continental mass when the tectonic plates moved it away from Antarctica and Africa.
05:31From that moment on, the local fauna evolved in a unique way, giving birth to species that could not be found anywhere else.
05:39Some of these animals still exist today, such as opossums, capybaras and chinchillas, tattoos, ants and other lazy creatures.
05:50Other species have disappeared, such as giant earthworms, larger than cars, or glyptodons, similar to giant tattoos, or extremely robust bone carapaces.
06:04There were also huge birds unable to fly, but able to hunt their prey.
06:09North of the American continent, animals still had access to the rest of the globe via the Bering Strait.
06:16The region was therefore populated by a wide variety of animals, including deer, bison, horses, camels, mammoths and mastodons, which cohabited with predators such as large felines, wolves and bears.
06:29About 3 million years ago, North America and South America were connected by a strip of land known as the Panama Strait, the result of new tectonic movements.
06:41An intense volcanic activity, which occurred 25 million years ago, also contributed to its formation.
06:48This terrestrial link allowed animals to migrate between the two continents, a process that went down in history as the Great Inter-American Fauna Exchange.
06:59During the Ice Age, huge glaciers periodically reached their maximum before withdrawing, which led to a decrease in sea levels and the probable transformation of forests into vast grassy plains, thus favoring the crossing of animals.
07:14Giant earthworms were among those who migrated north to Alaska.
07:20A particular species, Jefferson's Earthworm, even wandered in glacial tundras and cohabited with mammoths and caribou.
07:31Many North American predators ventured south. Among them were felines such as cougars, jaguars and smilodons with long canines.
07:40Wolves, foxes, otters, raccoons and other bears also took part in this migration.
07:47The short-faced bear, or Arctotherium for example, could reach 4 meters in height and weigh as much as a small car.
07:56In South America, the original ungulates of this part of the continent had evolved into a multitude of singular forms during their isolation.
08:05Imposing creatures of North American origin, such as gomphoters, related to elephants but endowed with unusual defenses, migrated south, thus being among the largest local species.
08:19The ancestors of the current llamas chose a home in the Andes, while deer, tapirs and peccaries thrived in the forests.
08:28The movement of animals between the two continents lasted for millennia, but the end of the ice age led to the extinction of many large animals, such as the lazy giants, unable to adapt to these new conditions.
08:41The North American species adapted better to these changes.
08:46Today, we still find tattoos, epic pigs and South American opossums in North America.
08:53But emblematic animals from South America, such as jaguars, llamas and bears with glasses, have disappeared from the North.
09:01Scientists believe that the prolonged isolation of South American species has made them more vulnerable to the upheaval of their environment.