No Animals Ever Pass This Invisible Border, Here's Why

Bright Side

There’s a mysterious invisible border in nature that no animal ever crosses, and scientists are still trying to figure out why. It’s not a wall, a fence, or anything humans built—it’s just there, like an unseen force field. Some researchers believe it has to do with things like magnetic fields, scent markers, or even instinct passed down through generations. Animals on one side stay put, and those on the other never step over, almost like they know something we don’t. It’s one of those weird natural mysteries that makes you wonder what else is going on in the animal kingdom. Want to know more? Stick around, because this one’s wild!  Credit: CC BY 4.0, https://creativecommons.org/licenses/by/4.0/ : Garden cement fence: By Mehdi Shahsavan, https://skfb.ly/oRFrZ Falcontoxodon aguilerai: By Jaime Chirinos, https://commons.wikimedia.org/wiki/File:Falcontoxodon_aguilerai.png CC BY-SA 4.0, https://creativecommons.org/licenses/by-sa/4.0/ : Ground sloth sculpture: by Jaap Roos art, Jaaproosart, https://commons.wikimedia.org/wiki/File:Ground_sloth_sculpture_made_by_Jaap_Roos_art.jpg Pleistocene-meso-megamammals: By Julio Lacerda, https://commons.wikimedia.org/wiki/File:A-Pleistocene-meso-megamammals-from-Sergipe-Brazil.jpg Eucalyptus deglupta: By Forest & Kim Starr, CC BY 3.0, https://creativecommons.org/licenses/by/3.0/ , https://commons.wikimedia.org/wiki/File:Starr_060703-8293_Eucalyptus_deglupta.jpg Animation is created by Bright Side.  ---------------------------------------------------------------------------------------- Music from TheSoul Sound: https://thesoul-sound.com/   Check our Bright Side podcast on Spotify and leave a positive review! https://open.spotify.com/show/0hUkPxD34jRLrMrJux4VxV   Subscribe to Bright Side: https://goo.gl/rQTJZz ---------------------------------------------------------------------------------------- Our Social Media: Facebook: https://www.facebook.com/brightside Instagram: https://www.instagram.com/brightside.official TikTok: https://www.tiktok.com/@brightside.official?lang=en Telegram: https://t.me/bright_side_official   Stock materials (photos, footages and other): https://www.depositphotos.com https://www.shutterstock.com https://www.eastnews.ru ----------------------------------------------------------------------------------------  For more videos and articles visit: http://www.brightside.me  ---------------------------------------------------------------------------------------- This video is made for entertainment purposes. We do not make any warranties about the completeness, safety and reliability. Any action you take upon the information in this video is strictly at your own risk, and we will not be liable for any damages or losses. It is the viewer's responsibility to use judgement, care and precaution if you plan to replicate.

Transcript

00:00This invisible line divides the world into two parts,

00:05and most animals, fish, and birds, for some reason, can't cross it.

00:10The line is called the Wallace Line, and it runs between Australia and Asia.

00:15It has its name after Alfred Russell Wallace,

00:18a British scientist and explorer who discovered it in 1859.

00:23He traveled to Asia to explore a group of islands called the Malay Archipelago.

00:29As Wallace walked through the jungles, climbed hills, and sailed on boats,

00:34he noticed something like an invisible wall.

00:38On its west side, in places like Borneo and Sumatra,

00:42he saw animals you might find in Asia.

00:45There were big rhinos munching on leaves and monkeys swinging from tree to tree.

00:50The forests were full of life, with all kinds of animals you'd expect to see in a jungle.

00:57But in places like Sulawesi and Lombok,

01:01just across the imaginary line he came up with,

01:04Wallace found animals more like the ones in Australia and colorful birds like cockatoos.

01:11The behaviors of animals differ on different sides of the Wallace Line.

01:15Some creatures are great at traveling across tough barriers like water, but others are not.

01:21For example, bats can fly across open water,

01:25but they sometimes cross the Wallace Line.

01:28On the other hand, big animals that live on land like elephants usually stay on just one side of the line.

01:35Some birds are shy and like to stay hidden in thick bushes and trees to avoid predators.

01:40They wouldn't feel safe flying over wide stretches of water with no place to hide.

01:46Plants don't stick to the Wallace Line as strictly as animals do,

01:50because they spread in their own unique ways, like with seeds carried by the wind, water, or animals.

01:57One plant genus, the eucalyptus, mostly stays on the Australian side,

02:02but one eucalyptus tree has made its way to the Philippines on the Asian side.

02:08Underwater, the Wallace Line doesn't matter as much.

02:12The area between the Wallace Line and Australia is called the Coral Triangle,

02:17and it's bursting with life!

02:20Now, after more than 150 years, scientists think they finally have an explanation of the Wallace Line mystery.

02:28They believe it all started about 35 million years ago,

02:32when Australia broke away from Antarctica and slowly moved up to crash into Asia.

02:38When this happened, the crash created a chain of islands called the Malay Archipelago between Asia and Australia.

02:46This caused extreme changes in the weather, which made the area very different and affected which animals could live there.

02:53Researchers used a computer model that looked at how more than 20,000 species of animals from both sides of the Wallace Line would have behaved millions of years ago.

03:04When Australia started to drift away from Antarctica, it opened up a huge new era of deep ocean around Antarctica.

03:12This is where the biggest ocean current on Earth, called the Antarctic Circumpolar Current, began to flow.

03:19This swirling current made the planet's climate much cooler and completely changed how animals could live in different places.

03:26But not all animals were affected in the same way.

03:30Indonesia stayed warm and rainy, which was perfect for animals from Asia.

03:35These creatures could hop from island to island like stepping stones and make their way toward Australia.

03:41But animals from Australia had a harder time.

03:44Over millions of years, they had gotten used to living in cooler, drier places.

03:48So the tropical islands didn't suit them as well.

03:53Scientists believe if we can see how animals adapted to big changes in weather patterns millions of years ago,

03:59we might be able to predict how today's animals will cope with a similar situation.

04:07Other scientists after Wallace also tried to describe and explain the invisible natural border between Asia and Australia,

04:14and came up with their lines.

04:17The Weber Line, for example, is in a slightly different location than the Wallace Line,

04:22between the Oriental and the Australasian faunal regions within Wallacea.

04:27It's a group of mainly Indonesian islands that are separated by deep water straits from the Asian and Australian continental shelves.

04:36They were never connected to the big continents by land,

04:39so animals that could swim, fly or float across the water made it to these islands.

04:44That's why the creatures living there are so unique and come from both Asia and Australia.

04:50Weber's Line is where the balance tips.

04:53If you go one way, most of the animals are from Asia.

04:56If you go the other way, most of the animals are from Australia.

05:01Another important migration event in the history of our planet happened in the Americas.

05:07Around 30 million years ago, South America became a separate landmass as tectonic plates moved and pulled it away from Antarctica and Africa.

05:17Once it was on its own, the animals living there started to evolve in unique ways,

05:22and turned into creatures you couldn't find anywhere else in the world.

05:27There were animals we still see today, like opossums.

05:30Giant rodents like capybaras and chinchillas.

05:33Armadillos, anteaters and sloths.

05:38Some of the animals from those times are now extinct.

05:41There were giant ground sloths, bigger than cars, roaming around.

05:46There were glyptodonts, which were like giant armadillos with super tough, bony shells.

05:52There were also huge, scary birds that couldn't fly but could chase down their prey.

05:59Up in North America, animals could still travel to other parts of the world through the Bering Strait.

06:05So North America was full of different animals like deer, bison, horses, camels, and even mammoths and mastodons.

06:17They all lived alongside predators like big cats, wolves, and bears.

06:24About 3 million years ago, the continents of North and South America got connected by a strip of land called the Isthmus of Panama.

06:33It formed because the tectonic plates shifted again.

06:38Some major volcanic activity between 25 million years ago also contributed to the process.

06:45Animals started to move between North and South America,

06:48and this long process went down in history as the Great American Interchange.

06:54During the Ice Age, huge glaciers in the north grew and shrank over tens of thousands of years.

07:01When the glaciers were at their biggest, they held so much water that the sea levels dropped,

07:07and forests probably turned into wide, grassy plains.

07:11So animals had the perfect conditions to cross over.

07:15Giant ground sloths were among the animals that went up north from South America, all the way to Alaska.

07:23One special kind even roamed the chilly tundras alongside woolly mammoths and caribou.

07:30Lots of North American predators decided to explore the south.

07:35There were cats like cougars, jaguars, and saber-toothed tigers with their giant teeth.

07:41Wolves, foxes, otters, raccoons, and bears also joined the migration.

07:47The short-faced bear could stand up to 13 feet tall and weigh as much as a small car.

07:54South America also had some funny-looking animals called sanus, or South American native undulates.

08:01These were hoofed mammals that evolved into all kinds of weird shapes while South America was isolated.

08:09Big animals from North America, for example, relatives of elephants with strange tusks,

08:14came to the south and became some of the largest creatures around.

08:19The ancestors of today's llamas settled in the Andes Mountains,

08:23and deer, tapirs, and peccaries thrived in the forests.

08:28Animals kept moving back and forth between the continents for thousands of years.

08:33As the Ice Age ended, many of the bigger animals, like the giant ground sloths, couldn't adapt and disappear.

08:40It seems North American animals were better at adapting to their new homes.

08:45You can find armadillos, porcupines, and opossums from South America in North America.

08:51But many of South America's most famous animals like jaguars, llamas, and spectacled bears left North America long ago.

09:01Scientists think South America's animals, after being isolated for millions of years,

09:06had a harder time dealing with new challenges when their ecosystems changed.

09:13That's it for today. So hey, if you pacified your curiosity, then give the video a like and share it with your friends.

09:19Or if you want more, just click on these videos and stay on the Bright Side!

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