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00:00A Dinosaur with a giant sail on its back.
00:07It's a Spinosaurus.
00:10A 15 meter long, huge carnivore.
00:15It's wading out into the sea.
00:21Some dinosaurs seem to have ventured into the water.
00:42But maybe...
00:48They should have stayed on land.
00:54Because at the time, the sea was home to real monsters.
00:59Ones to terrify even dinosaurs.
01:04The primeval ocean ruled by giant predators.
01:18What dramatic life and death encounters unfolded in the seas of the Dinosaur Age?
01:28Discoveries by the world's top researchers gave the first glimpse into the little known domain of life on prehistoric Earth.
01:38These sea monsters belonged to a different branch of the evolutionary tree from dinosaurs.
01:44They were marine reptiles.
01:49Among them was Mosasaurus, the apex predator of the ancient oceans.
01:58As Tyrannosaurus Rex ruled the land, Mosasaurus ruled the sea.
02:09How did it get to the top of the food chain in the underwater world?
02:16The ancestors of Mosasaurus were relatively small creatures living in the shadow of the dinosaurs.
02:27But after tens of thousands of generations, they turned the tables on the dinosaurs.
02:37The stage for this drama is the Earth of 66 million years ago.
02:44The epoch when the dinosaurs were flourishing.
02:50A vast blue ocean climbed beyond the familiar landscape ruled by the dinosaurs.
03:07It hides a dramatic world of colossal marine reptiles.
03:13A giant ball composed of thousands of fish.
03:38This potential feast draws all kinds of marine carnivores.
03:47First to appear is a marine reptile with a bizarre appearance.
03:51A species of plesiosaur.
03:53It's eight meters long.
04:03It hides its amazingly long neck and sharp snaggle teeth for snapping up fish.
04:18Plesiosaurus flourished the longest among marine reptiles in the dino world seas.
04:24Up from the depths swims the king of the fish.
04:39The five meter long Zyvectinus.
04:45It was among the largest predatory fish species during the age of dinosaurs.
04:52With a mouth big enough to gulp down a person in one bite.
05:00It hunted prey of all types and sizes.
05:06Long necked plesiosaurs and giant Zyvectinus may have terrorized the oceans.
05:21But they were not the true rulers of the sea.
05:27Tearing apart the Zyvectinus with one bite, the giant Mosasaur makes its entrance.
05:46At 13 meters in length, it's bigger than a large city bus.
05:53This is the largest individual in this ocean.
06:07She exerts her mighty predatory power over the ocean.
06:11The other Mosasauruses gather around, hoping to feast on her leftovers.
06:28Other Mosasauruses gather around, hoping to feast on her leftovers.
06:32She slams her body fiercely into her rivals.
06:39As a hunter of the seas, she is without rival.
06:56A few days later, she floats at the surface.
07:17With her head above the waves, she seems to be scanning for prey.
07:24With her head above the waves, she seems to be scanning for prey.
07:30She looks to be getting frightened.
07:32She looks to be frozen.
07:33She is the most innocent during the season.
07:38She is the most innocent person.
07:41She just looks to a hunter and she looks to be the SERVITE,
07:43She is the most innocent person but they are being damaged.
07:45She is the most innocent, not innocent person.
07:47She is the most innocent people over the island.
07:49She is the most innocent person.
07:51I am dying to find a wait to see the cat.
07:56It's a pair of Tyrannosauruses.
08:03They've driven their prey into the surf and are preparing to bring it down.
08:26I know.
08:49The Ozasaur attacks one of the Tyrannosauruses.
08:56The Tyrannosaurus isn't used to moving around in the surf.
09:02Without firm footing, it can't fully exert its own fearsome power.
09:10The Tyrannosaurus isn't used to moving around in the surf.
09:15Without firm footing, it can't fully exert its own fearsome power.
09:26The Mosasaur is powerful enough to deliver the killing woe.
09:30Even to a Tyrannosaurus.
09:35A few years back, a Mosasaurus fossil was found in Japan.
09:40In 2014, two high school students in Kobe discovered it in the woods.
09:43A few years back, a Mosasaurus fossil was found in Japan.
09:49A few years back, a Mosasaurus fossil was found in Japan.
09:54In 2014, two high school students in Kobe discovered it in the woods.
10:12Here is the fossil they found.
10:14At first, we didn't think it was that important.
10:20Just a random shell fossil or something.
10:23I realized these boys have made an amazing find.
10:28Further study of the fossil determined that it was part of a Mosasaurus jaw.
10:34What's remarkable is the size.
10:36When compared to other Mosasaurus fossils found in other countries,
10:42this jaw fossil indicates a head almost two meters long.
10:51That means the whole body was 13 meters long.
10:55It was among the largest Mosasaur ever found.
11:14Mosasaurus is known for its bite force comparable to a Tyrannosaurus.
11:19With a jaw lined with razor sharp teeth,
11:22it could prey on any creature living in the water.
11:27That is proven by the contents of a fossil stomach.
11:31It contained fish, sharks, birds, and even other Mosasaurus.
11:42And the latest research indicates that giant marine reptiles like Mosasaurus
11:47would also attack dinosaurs.
11:52This can be seen in this fossilized skull of a Plesiosaurus,
11:58an extinct marine reptile.
12:03One of the most remarkable and extremely rare findings with this skull
12:09is the association of these armor plates, things called skews,
12:15and one which was preserved inside the roof of the mouth.
12:19The triangular part is the dinosaur scoot.
12:23Analysis revealed that this scoot came from the back of an armored dinosaur.
12:38Researchers see this as evidence that Mosasaurus and other marine reptiles
12:41also ate land-dwelling dinosaurs.
12:47It was feeding on a swimming dinosaur.
12:51So this specimen shows a definite interaction between predator and prey,
12:54an interaction between a marine reptile and a terrestrial dinosaur.
13:02Recently, it's also become clear that Mosasaurus was quite clever.
13:06The clues are found in this museum.
13:07The fossil is of an ammonite, a giant spiral-shelled mollusk.
13:20This ammonite's shell has multiple round holes in it.
13:27Holes that line up perfectly with Mosasaurus' teeth.
13:35But how do holes in a shell give evidence that Mosasaurus was smart?
13:43Let's return to 66 million years ago.
13:48Soaring through the skies of the dino world are terraces, large flying reptiles.
14:10The Mosasaur makes a sneak attack.
14:14The Mosasaur makes a sneak attack.
14:17Like killer whales of today, Mosasaurus is thought to have used stealthy ambush-hunting tactics.
14:20Here's a group of Ammonites.
14:21They were another favorite food of Mosasaurus.
14:23The Mosasaurus is thought to have used stealthy ambush-hunting tactics.
14:27The Mosasaur makes a sneak attack.
14:29The Mosasaur makes a sneak attack.
14:33Like killer whales of today, Mosasaurus is thought to have used stealthy ambush-hunting tactics.
14:40Here's a group of Ammonites.
14:47They were another favorite food of Mosasaurus.
14:53But ammonite shells are very tough.
14:56Even Mosasaurus can't just crack them open.
14:59And despite their cumbersome appearance, Ammonites are surprisingly nimble swimmers.
15:08That's where the Mosasaur's strategy comes in.
15:18Because of their large shells, Ammonites have a blind spot behind them.
15:22Our Mosasaur sneaks up, quietly from behind.
15:36A plan of attack that proves ingenious.
15:40She seizes the Ammonite in her jaws.
15:45But soon, she lets it go.
15:53Ammonites control their movements by adjusting the pressure inside the chambers in their shells that give them buoyancy.
16:03If the chambers are damaged, they just sink.
16:07And can't nimbly move anymore.
16:10The Mosasaur targets the weakness by punching holes in the shell to incapacitate their swift, getaway movements.
16:18Mosasaurus was a cunning hunter that used clever strategies to stalk and kill its prey.
16:28Power and strategies.
16:31Mosasaurus had both.
16:33And that enabled it to rule the seas.
16:36Thousands of fossils found around the world so far corroborate how Mosasaurus was thriving globally.
16:43Takuya Kanishi is a leading expert on Mosasaurs.
16:49He says that the tremendous success of these marine reptiles is exceptional in the history of life on Earth.
16:56From the time the Mosasaur group first appeared, in only about 10 million years, they spread through the planet's oceans and grew larger in size.
17:10The speed of their rise stands out in the history of life on our planet.
17:15During the age of the dinosaurs, Mosasaurus rose rapidly to dominance in the sea.
17:30Even when she's sleeping, other predators don't dare bother her.
17:54But before the remarkable evolutionary rise, they were just small creatures cowering in the shadow of the dinosaurs.
18:06About 300 million years ago, the evolution of Mosasaurs and dinosaurs diverged from their common ancestor, a primitive reptile.
18:16The reptilian lineage separated into two large groups, the lizard and snake branch, and the crocodilians.
18:26Mosasaurs evolved from the former, while dinosaurs emerged from the latter.
18:31The fates of the Mosasaur group and dinosaurs were different.
18:37By the time the first Mosasaurus species appeared on Earth, dinosaurs had already evolved into large, dominant creatures.
18:46Meanwhile, what did our Proto-Mosasaurus look like?
18:50This is the coast of Africa, a hundred million years ago.
19:03Proto-Mosasaurus is not very big, less than a meter long.
19:13It's living on land, not in the water.
19:17It's living on land, not in the water.
19:20It's living on land, not in the water.
19:21The Proto-Mosasaurus scampers around at the feet of dinosaurs of enormous size.
19:45The Proto-Mosasaurus scampers around at the feet of dinosaurs of enormous size.
19:51It spots prey, a crayfish.
19:59It spots prey, a crayfish.
20:15The ancient reptile gulps it down.
20:19The protomososaurus belongs to the same reptilian group as snakes that can open their mouths
20:35very wide.
20:39It had the type of jaw that can stretch so much it can even swallow large prey whole.
20:45In this epoch, food was scarce on the seashore.
20:50To survive the harsh environment, the gaping mouth was quite helpful.
20:55The scrawny mosasaurus ancestor could quickly gobble up any prey it could find.
21:04A large predator, Apolisaurus, approaches.
21:07The protomososaurus flee in all directions.
21:14The protomososaurus flee in all directions.
21:20The protomososaurus flee in all directions.
21:26The protomososaurus flee in all directions, looking for anywhere to escape.
21:47The protomosophodel.
21:51However, it happens to be a sharp attempt.
21:57The protomosophel on the oftalus8f1r1, leading to the protomosophel.
22:03The protomosophel.
22:07The protomosophel.
22:08The protodi.
22:09The protomosophel.
22:11The protomosophel.
22:12The protomosophel.
22:13Let's go.
22:43Let's go.
23:13To avoid ferocious predators, Mosasaurus's ancestors, over hundreds of generations, adapted to aquatic life.
23:23Protomosasaurus mastered swimming.
23:34In the ancient ocean, fish are abundant.
23:54Unlike on land, ruled by the dinosaurs, the sea offered plenty of food.
24:06The wide-opening mouth comes in quite handy for chasing after fish.
24:11The gaping mouth first evolved on land to aid survival in a food-scarce environment.
24:32But by chance, it proved to be a mighty weapon in the sea.
24:48And in this epoch, there were few carnivorous enemies in the sea, or rival predators competing for prey.
24:57This environment ensured Protomosasaurus's survival.
25:01Now, we fast-forward 30 million years.
25:11In the sea of 66 million years ago, our Mosasaur is chasing a school of fish.
25:20From a timid, lizard-like creature, scuttling in the shadow of the dinosaurs.
25:28The lineage has quickly grown into this large, dominant marine prey.
25:33With the help of the Gaten mouth, they could hunt anyone.
25:40Now, Mosasaurus is the king of the primeval oceans.
25:46It even preys on its ancient enemy.
25:51We'll be a man.
25:53Let's go!
26:19The fully evolved Mosasaurus reigns supreme, fearing nothing, not even the largest dinosaurs.
26:33The massive mouth was one secret of its success, and now scientists have begun to identify
26:39another one.
26:47Adeki Kato of Shizuka University does research on the evolution of Mosasaurus by studying the
26:53characteristics of their living relatives, lizards.
27:04Lizards have a wide variety of shapes and interesting behaviors.
27:08They are showing us more and more about the evolution of life.
27:14Kato is on an expedition in Australia, home to more than a thousand species of lizards.
27:24And some of these species exhibit a trait that was critical to the flourishing of Mosasaurus.
27:31Oh, there's something, right there.
27:39Kato frantically grabs at the lizard as it tries to escape.
27:43Kato frantically grabs the lizard as it tries to escape.
27:52There it is.
27:54A common dwarf skink.
27:58It's a tiny lizard.
27:59This one's full-grown.
28:03But I'm looking for something else.
28:06Kato spots another lizard.
28:13Gotcha.
28:14Look.
28:15An inland bearded dragon.
28:18Look at those long toes and long limbs.
28:23But once again, it's not the lizard he's looking for.
28:27There's one.
28:28Look.
28:29Look.
28:30Look.
28:31He finally found his target lizard.
28:39She's fighting back hard.
28:51Stronger than expected.
28:55The lizard Kato wanted a shingleback.
29:04It's 30 centimeters long and armored in tough scales.
29:11Isn't this species dangerous?
29:17It has powerful jaws, so if you get bit, it will do damage.
29:23Modern shinglebacks have one trait that reveals the key to the success of mosasaurs.
29:30She's got one.
29:32See?
29:33The belly's swollen.
29:34It's large.
29:35Right here.
29:36There's a baby.
29:38Probably just one.
29:40She's pregnant.
29:42Nah.
29:43Shinglebacks are one of the very few reptiles that are viviparous, meaning they give birth
29:49to live young.
29:51Most lizards don't give live birth, but they lay eggs instead.
30:06This rare footage shows shinglebacks delivering their young alive.
30:15The trait of live birth may have evolved in these lizards because it gave more chances of survival of their offspring in harsh conditions.
30:25Cold, hot, dry.
30:28Ancestral mosasaurs also lived in harsh conditions, constantly threatened by powerful predators like dinosaurs, which must have led them to acquire the ability of live birth.
30:45Evidence found in Europe shows that live birth had already evolved an early mosasaur species.
30:56This is a fossil of Carcosaurus marcus seti, a primitive mosasaur species soon after the lineage took to the sea.
31:05Look closely at the stomach.
31:07There's a slight indentation here.
31:10This is actually the eye of a baby.
31:19Analysis of the fossil revealed that this ancestral mosasaur had four babies in its belly.
31:26Carcosaurus marcus seti was a very interesting animal also because it was a viviparous animal.
31:35It allowed these animals to really cut every connection with the earth and to start to move even to deep water very, very outside the continent.
31:49What happened when mosasaurus evolved to give live birth?
31:54In the world where ancestral mosasaurs lived, this adaptation offered some survival advantages.
32:06An ancient species of sea turtle has come ashore en masse.
32:13Like mosasaurs, their ancestors moved from the land to the sea.
32:22Although the turtles live at sea, they spawn on land.
32:27They lay their eggs on sandy beaches.
32:31Although domestic, it could happen quickly as many times as it were protected here, it caused the fish to Attajane, especially the map in those anyities where theardı aquac damaged, 50 percent clairement interacted and was clearly on several industrial ports.
32:32What happened when in the 생men is nowhere, is there more or less 1920 times, if it'szuk
32:38Attain?
32:38òsurām
32:43So, what happened the Messins are not easy now as a fossil missus.
32:50You also must have the message.
32:52It was Quintosh.
32:53When left on land, eggs are exposed to the dangers of dinosaurs finding and eating them.
33:17Quite far away, the protomosasaurus is also at the shoreline.
33:33This one is pregnant.
33:44Protomosasaurus has acquired the ability to grow young within its body.
33:53The newborns are very small.
34:08Delivered underwater, they immediately head to the surface to take their first breaths.
34:22They're born tail first so they can keep breathing until the last possible moment.
34:31The trait of live birth must have dramatically increased the survival rate of young and eliminated
34:42the need to return to shore to lay eggs.
34:45It allowed protomosasaurus to go out into the open sea.
34:50Eventually, their offspring would occupy all the seas across the planet.
35:00The latest study reveals that mosasaurs may have further evolved pregnancy.
35:11The discovery of this small fossil was published in 2018.
35:18Based on bone characteristics, it was determined to be part of the jawbone from a baby growing
35:24inside its parent.
35:30From the size of that jaw, the baby mosasaur is estimated to have been 2.2 meters long.
35:44We now know that mosasaurus babies were extremely large at birth.
35:51In order to give birth to such a big baby, the mother would have needed an organ like a placenta,
35:56which could provide enough nutrition to the baby to help it grow that large while inside
36:01the mother's body.
36:07The process of mosasaur evolution may have brought forth an organ like a placenta, which is also
36:13a hallmark of mammals.
36:19The placenta is a special organ.
36:22Animals that give birth do not always have one.
36:26Through the placenta, the baby inside the parent body could continuously receive plenty of nourishment
36:32and thus grow very large.
36:41In the case of mosasaurus, the gestation period continued for about one year.
36:47And the long pregnancy may have brought about a close bond between mother and baby.
36:54We can see that result in the shingleback, a modern lizard that also give birth to live young.
37:02The shingleback has a placenta, and the baby can grow to one-third of its mother's size
37:08before birth.
37:11The shingleback is also extremely unusual among lizards, as it takes good care of its young.
37:32The mother licks her child, and now the child licks its mother.
37:41The mother uses a flick of her tongue to the child to catch its scent and confirms that it's her own offspring.
37:52It is observed that the mother shows maternal affection.
37:56And after birth, the child will stay with its mother for several months, or even a year.
38:02Growing large babies inside the body means they can only produce a small number of them.
38:14And the mother tries to protect her few offspring with the utmost care, creating a close bond between mother and child.
38:27This is an exceptional behavior not found in any other lizard.
38:38Luis Chiappe, a world-renowned paleontologist, has spent years researching the reproductive behaviors
38:45of ancient species.
38:49He believes that mosasaurs and other marine reptiles may have also nurtured a strong family bond.
39:03We can infer that there was a strong bond between mother and baby.
39:09This bond most likely provided protection to the baby, but it also provided the opportunity
39:17to gain other skills, such as, for example, learn how to hunt or where to migrate, and other
39:26skills that would be critical for the baby's survival.
39:28It was a very good strategy.
39:29As a matter of fact, it's a very good strategy for vertebrates in general.
39:36Sixty-six million years ago.
39:42The epic when mosasaurs were in their prime.
39:54The epic when the morasaurs were in the early days.
40:01The epic when the morasaurs were in the early days.
40:08Our morasaurs belly is swollen.
40:18She has been pregnant for a year. Her delivery date is coming soon.
40:48A few days later, on the night of a full moon,
41:17a large group of mosasaurs have gathered in the shallows.
41:31More than 50 of them.
41:36They are all pregnant females. Fossil evidence strongly suggests that they gather to give birth to their young.
41:44Our mosasaur is among them.
41:50It's obvious she's suffering labor pains.
41:59Shinglebacks, the modern day lizard that give live birth, are also known to have labor pains.
42:17Delivering such big babies may inevitably have involved a huge strain.
42:27The mosasaurus newborns are more than two meters long.
42:31If the newborns don't get air to breathe right away, they'll drown.
42:51Perhaps mother can give them a bit of help reaching the surface.
43:07In another part of the ocean shallows, plesiosaurs gather.
43:25They also give live birth to large young.
43:29In the age of dinosaurs, these gigantic marine reptiles became viviparous.
43:39And made the seas their domain.
43:58Mothers and babies have survived the strain of birth.
44:12But now, a school of giant fish approaches.
44:18They are Xiphactids.
44:23And they aim to devour the mosasaurs newborns.
44:29Our mothers and babies try to escape the onslaught.
44:42But one of them is lagging behind.
44:54Mother comes to the rescue.
44:58The mosasaur mothers drive off the monster fish.
45:10Live birth and the strong family bond.
45:13By ensuring the survival of their offspring quite effectively,
45:17mosasaurus could successfully thrive in the seas of the dinosaur age.
45:23The lineage of the ocean rulers continues.
45:41On land, the feathered dinosaur, Dinachyrus, engages in mating rituals to produce offspring.
45:53And the highly intelligent Troodon raises the young for the next generation.
46:09They thrive, protecting and taking good care of their offspring.
46:14And that ability allowed these lineages to last for 150 million years.
46:21Until suddenly interrupted by a huge asteroid, 10 kilometers across, bearing down on Earth.
46:37Until suddenly interrupted by a huge asteroid, 10 kilometers across, bearing down on Earth.
46:49The impact led to 75% of all species.
47:07on Earth becoming extinct.
47:23Despite their unprecedented success, dinosaurs and marine reptiles suddenly disappeared from the middle of their peak.
47:3566 million years later, we are living on this planet that was once home to the huge reptilians.
47:42direcript star visitedإ2d3d3d3d4 commune
47:46who are living on Earth to alive and習 anymore.
47:48That creature on earth remains.
47:50I often think about the fact that even though mosasaurus was at the top of the food chain
47:54when the ecosystem radically shifted, they vanished in no time.
47:59Right now humanity is thriving, to an amazing degree.
48:03But what does the future hold?
48:08the future hold? Maybe the fate of Mosasaurus points to the answers.
48:17In the amazing dino world, the dramatic stories of life beyond our wildest imagination
48:24play out in the planet. More stories are yet to be told by fossils, the memories of each
48:32and earth that are still waiting to be engulfed across the world.