Documentary, T-Rex: An Evolutionary Journey, NHK
#AncientEarth #Documentary #Dinosaurs #Prehistoric #Evolutionary
#AncientEarth #Documentary #Dinosaurs #Prehistoric #Evolutionary
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AnimalsTranscript
00:0070 million years ago, the mightiest dinosaur that ever lived roamed the Earth.
00:21Its name was Tyrannosaurus rex.
00:29It was 13 meters long and weighed 6 tons.
00:34This awesomely powerful creature was king of the dinosaurs.
00:39Much about T-Rex has been shrouded in mystery.
00:42Now, with modern technology, a clear picture is taking shape.
00:49Remarkable physical capabilities that defy conventional wisdom.
00:58An advanced brain and intellect for hunting.
01:04We look at their brain and wonder whether that enlarged cerebrum may have actually had the capacity to be involved in sort of a coordinated group hunting effort.
01:17In addition, new fossil vines from around the world are revealing the origins of this enormous predator.
01:24It turns out that T-Rex's ancestors were actually small and frail.
01:33They weren't, you know, the big bears or the big lions or the big tigers at the top of the food chain.
01:40They were something much smaller, much weaker.
01:45Somehow, Tyrannosaurus transform from small creatures threatened by their enemies into the most powerful Tyrannosaurus of the world.
01:56Starting with the very earliest ancestors, we'll explore an amazing tale of evolution.
02:02Siblings on a journey in search of new lands.
02:05Siblings on a journey in search of new lands.
02:08They cross paths with a place of carnivore.
02:11Which will reign supreme.
02:16The king of kings, Tyrannosaurus rex.
02:23This is a story of 100 million years of remarkable evolution.
02:37The first Tyrannosaurus fossils were discovered in the United States in the early 20th century.
02:50The dinosaur's monstrous appearance inspired its name.
02:54Tyrannosaurus rex.
02:56Tyrant lizard king.
02:58Or T-Rex for short.
03:07For more than a century, scientists have been working to piece together T-Rex's evolution.
03:13The T-Rex is one of the top researchers in the field.
03:20Steven Brussati is one of the top researchers in the field.
03:26So everybody in the world has heard a T-Rex.
03:31But for a long time there have been some big mysteries about where T-Rex came from.
03:36How it evolved. How it got so big.
03:38And these have been mysteries for many decades.
03:41But finally, over the last 15 years, people all over the world have been finding older, smaller, more primitive Tyrannosaurus that tell us where the big ones came from.
03:54Scientists are zeroing in on T-Rex's roots.
03:57They've determined that its earliest ancestors first emerged far from North America.
04:14This is the Zhanggao Basin in the Xinjiang Uyghur Autonomous Region of China.
04:19Now dry, this landscape was once home to many different types of dinosaurs.
04:34In recent years, excavations have unearthed a wide variety of fossils.
04:39Xu Xing has led some of these digs.
04:46In the morning, people are very tired.
04:48But they haven't found great things in this day.
04:49They've found a lot of things in the same day.
04:55One day in this eight or ten hours, at the temperature of 3-10 degrees,
04:59It's not very large.
05:01The demand for people's lives are very large.
05:03I am walking walking.
05:04I have a team called Uy涛.
05:07Of course, from the distance he's been far from.
05:10He's very excited to hear me.
05:12It's very fun.
05:13I know there's something important to find in a small sand坡.
05:18We saw that it could be a new species.
05:22So we saw a small sand坡.
05:27It's very fun.
05:36Inside a 160 million year old soil strata,
05:40they found a completely new meat-eating dinosaur.
05:44A crown-like appendage on its head inspired its name,
05:48Guanlong, or crown lizard.
05:52Xu and his team conducted a detailed analysis of the teeth and bones.
05:57They determined that Guanlong was T-Rex's ancestor.
06:03We knew that we could have the most famous
06:07暴龍 family.
06:09It was very, very excited.
06:15Ah, there they are.
06:17A group of Guanlong siblings.
06:19They're on the hunt.
06:24One takes off.
06:26Perhaps he's the oldest.
06:28He closes in on his prey.
06:34But he's no match.
06:42At this point in time, the Guanlong was just three meters,
06:46dwarfed by the 13-meter-long T-Rex.
06:49It weighed only 75 kilograms,
06:51one-eightieth of the weight of its massive cousin.
06:57The very oldest tyrannosaurs were much, much different, much smaller.
07:01But they didn't have anywhere near the firepower of a T-Rex.
07:05They were kind of like, you know, cats or dogs,
07:08kind of that type of animal.
07:10They weren't, you know, the big bears or the big lions
07:13or the big tigers at the top of the food chain.
07:16How did such a small and relatively weak creature
07:21eventually lead to T-Rex,
07:24the largest dinosaur of them all?
07:37The story of Tyrannosaurs is really a story about evolution.
07:41And one of the things that it tells us
07:43is that evolution is unpredictable.
07:45When those very first Tyrannosaurs like Guanlong
07:48entered the scene 170 million years ago,
07:51you never would have thought that they would ultimately evolve
07:54into giant, monstrous animals like T-Rex.
07:57But that's what happened.
07:59How were they able to survive for so long,
08:02for 80 million years as these small, human-sized carnivores?
08:06And then maybe the biggest mystery of all,
08:09how were those small Tyrannosaurs able to switch
08:11and become these giant, dominant super predators?
08:15The keys to unlocking these mysteries are newly discovered fossils
08:24from around the world.
08:25Researchers have discovered 28 species related to T-Rex.
08:29Brussati has conducted detailed analyses of the bones of some of these specimens.
08:41His goal was to clarify the process behind T-Rex's evolution.
08:46The approach he used is called phylogenetic analysis.
08:53We have hundreds and hundreds of those features that vary in these dinosaurs.
08:58Some have the bones, some don't.
09:00Some have small muscle attachments, some have big ones.
09:02Some have triangle-shaped bones or projections,
09:05others have square-shaped ones.
09:07Those kind of features that are variable.
09:09Brussati's analyses have illuminated 366 distinctive characteristics of Tyrannosaur bones.
09:20And the data he's amassed formed the basis for mapping T-Rex's family tree.
09:27The results confirm that the diminutive Guanlong
09:30was indeed the most primitive species of Tyrannosaur.
09:35From the time the first Guanlong emerged until T-Rex appeared,
09:39took 100 million years.
09:41Over this time, dramatic evolutionary advances created a creature of unparalleled dominance.
09:51So it is an unusual animal, a freak of nature, a feat of evolution.
09:56And I'm fascinated to learn, to try to understand how evolution makes an animal like T-Rex.
10:04That's the mystery that drives me in the research that I do.
10:11One hundred and sixty million years ago,
10:14China's Jenga Basin was home to the Guanlong.
10:17This species then migrated to North America.
10:21And about seventy million years ago, T-Rex appeared.
10:25The question is why T-Rex's ancestors left their familiar environment and set out on their epic journey.
10:37A clue can be found in the southern reaches of the Pacific Ocean.
10:49Five thousand meters beneath the surface lies an enormous lava plateau.
10:54This is the only one that's going to be realized by the size of T-Rex.
10:57Now, Hyku Okochi has studied the formation.
10:59Now Hyku Okochi has studied the formation.
11:04My size is the size of T-Rex, and the size is a huge part.
11:07This huge lava mass was created by a major geological event 120 million years ago.
11:30Deep inside the earth is a swirling mass of matter called the mantle.
11:37Magma suddenly surged up, erupting through fissures in the ocean floor.
11:46The Pacific Ocean wasn't the only place this occurred.
11:51All over the world, volcanoes violently burst to life.
11:57These major eruptions also occurred on the Eurasian continent, where the primitive Tyrannosaurs lived.
12:07They had no choice but to flee.
12:13Leaving familiar territory behind, they began a journey into the unknown.
12:19They headed toward the north for a reason.
12:34Climate change.
12:36The gases released by volcanic eruptions contained large amounts of carbon dioxide.
12:40This triggered global warming.
12:44The mass mass mass of carbon dioxide.
12:47The carbon dioxide dioxide is now rising up.
12:50The carbon dioxide of carbon dioxide is now rising up.
12:53The gas mass mass will increase the volume of carbon dioxide.
12:54効果が起きまして植生をですね大きく
12:58極限まで広げそしてそれが最終的には
13:02馬橋を言うのですね
13:05生態を変えてあるいは進化を起こした
13:09いうふうに考えても不思議ではないと思います
13:16As the earth warned lush forests sprouted up from Siberia to the Arctic.
13:24Xu Xing believes this greening of the North encouraged the Tyrannosaurus migration.
13:54Triceratops fossils have been found from Eurasia to North America, and they're often found together with fossils of Tyrannosaurus.
14:08As the forests spread further north, the plant-eating dinosaurs' range expanded.
14:17Scientists believe this is what prompted T. rex's ancestors to begin their migration.
14:24Into the unknown.
14:29Searching for a new home with bountiful gain, they start out on their epic journey.
14:43They arrive on the eastern edge of the Eurasian continent.
14:47In front of them is a vast ocean.
14:49And just when it seems they can't go any further, something incredible happens.
15:03Tectonic shifts bring the Eurasian and American continents closer together.
15:07Then, a land bridge appears, closing the gap between them.
15:16A path has opened.
15:20The two siblings make their way toward it, and head to a new land.
15:24The pair arrives in North America.
15:25It's a vast expanse of land, covered in lush forests.
15:37But...
15:38It turns out, large, meat-eating dinosaurs also live here.
15:52Before T. rex, other carnivorous dinosaurs ruled the Americas.
16:04Scientists have found fossil remains in the deserts of Utah.
16:07Lindsay Zano is a paleontologist who has explored the area.
16:21She had been excavating for five years.
16:24Then, in 2013, she made a significant discovery.
16:28And I was coming around the corner on a low hill and spotted some bones sticking out of the side of the hill.
16:41So I got down and looked at the bone and could tell instantly that it was a theropod bone.
16:47A very large theropod by the looks of it.
16:49And we got very, very excited right away that we'd found a very large species that had never been seen before.
17:01Now, the real work began.
17:04Team member Peter Makovicki took the fossil to Chicago for further study.
17:11His specialty is analyzing dinosaur bones.
17:14The bones we have here are parts of the skeleton of a large carnivorous dinosaur.
17:23Even though it's big and superficially might look like Tyrannosaurus,
17:28it actually belongs to a very different lineage of meat-eating dinosaurs.
17:33The size of the bones suggested the dinosaur measured about 11 meters from head to tail.
17:39It's a relative of Allosaurus from the Jurassic era and is known as Siach.
17:48Experts believe this dinosaur had razor-sharp claws and teeth like knives.
17:53Such features point to a mega-predator.
17:56The name Siach actually comes from the Ute Indian language.
18:02It refers to sort of a cannibalistic clown monster, sort of a dangerous creature in their legends.
18:10And it is by far the biggest theropod and would likely have been the top predator in its ecosystem.
18:21Close to the Siach fossil find, Xano has recently discovered a relative of Tyrannosaurus.
18:26This is a tooth from one of the mysterious small Tyrannosaurus we find here in these rocks that are about 98 million years old.
18:40We find the tantalizing remains of tiny little Tyrannosaurus, about the size maybe of a small horse.
18:46A tooth from this dinosaur is just about one-tenth the size of that of a T-Rex.
18:58So the Tyrannosaurus living here were quite small.
19:01They were living in the shadow of dinosaurs like Siach.
19:04The weak Tyrannosaurus siblings were now living side-by-side with this formidable beast.
19:09The weak Tyrannosaurus siblings were now living side-by-side with this formidable beast.
19:14They were absolutely out-rivaled in size and in power.
19:35Well, I think, you know, if the small Tyrannosaurus that were alive at this time would have run into Siach,
19:46it would have been sort of like a fox meeting a lion or a tiger.
19:51There's no doubt that there was a very vast difference in body size.
19:55So basically what we have is evidence that Tyrannosaurus were present at the time,
20:01but would have occupied a much lower trophic level among the carnivores than Siach.
20:11Siach stood atop the ecosystem.
20:14It was a dangerous environment for the much weaker Tyrannosaurus,
20:18but somehow they managed to survive.
20:25To find out more, Brussati has done research all over the world.
20:32In 2016, he came across one fossil that provided some clear answers.
20:40It was found in Uzbekistan in Central Asia.
20:46An analysis revealed it was from the skull of a new species of Tyrannosaurus.
20:50It's called Timolengia and measured three meters long.
20:57At a glance, it doesn't seem too different from its smaller ancestors.
21:08But internally, it's dramatically different.
21:12We're able to look into its brain, into the ear using CAT scans,
21:20and we can see it had a big brain, very intelligent animal.
21:22We can see it had an ear that was really sophisticated.
21:25Really good at hearing a wide range of sounds.
21:28Brussati and his colleagues took scans of the cranium.
21:32Inside the inner ear is the cochlear duct,
21:36which is responsible for picking up faint sounds.
21:38They found that in Timolengia, it had significantly evolved.
21:44So what this is telling us is that these small Tyrannosaurs were evolving bigger brains,
21:50greater intelligence, better senses, when they were living in the shadows,
21:55when they were trying to survive in a world dominated by the Allosaurs and other big predators.
21:59Early small Tyrannosaurs developed a keen sense of hearing.
22:06That allowed them to quickly sense enemies and escape, helping them to survive.
22:16But fleeing wouldn't have been enough to challenge and overtake Siatch's dominant position.
22:22There's more to the mystery of how descendants of these diminutive siblings would have gone on to rule the dinosaur world.
22:38For many years, the evolutionary path from Guanlong to the giant T-Rex contained puzzling holes.
22:44So, we know a lot about the very earliest Tyrannosaurs now.
22:50We know they were small.
22:52We know a lot about the latest Tyrannosaurs.
22:53We know they were huge.
22:55But in the middle, there's a gap in the fossil record, a dark period of Tyrannosaur history where we know nothing.
23:01No fossils.
23:02The Tyrannosaur's 100 million year evolutionary history contains an intriguing hole.
23:11It was during this time that the spectacular advances that led to T-Rex occurred.
23:21Mark Lowen has been researching this mystery.
23:23He's focused in on an ancient landmass on the North American continent called Laramidia.
23:36The real changing point of Tyrannosaur evolution was the isolation and evolution that happened on Laramidia.
23:44Isolated populations of dinosaurs could evolve in isolation from other dinosaurs.
23:49Around 90 million years ago, global warming caused sea levels to rise.
23:58This led to monumental flooding on the North American continent, causing it to become divided.
24:04The dinosaurs lived in the western part of the continent.
24:08Much of the land was covered with steep mountain ranges.
24:13Rising waters drove the dinosaurs to narrow strips of level land, where they became isolated.
24:19In these densely populated areas, meat-eaters would have a significantly greater chance of finding prey.
24:43Lowen believes this is precisely what sped up the dinosaurs' evolution.
24:47This crucible of evolution that is Laramidia, the small populations were able to undergo dramatic change and rapid evolution.
25:00Revolutionary advances took place in many different creatures.
25:04Ankylosaurus evolved thick, bumpy skin, like protective armor.
25:05Ankylosaurus evolved thick, bumpy skin, like protective armor.
25:09Members of the Ornithomimus family developed the ability to run 60 kilometers per hour to escape predators.
25:13Similarly pronounced changes occurred among the triceratops.
25:14Similarly pronounced changes occurred among the triceratops ancestors, hunted by tyrannosaurs.
25:18They adapted for survival by becoming massively large.
25:19They adapted for survival by becoming massively large.
25:23This gave them the power to repel attacks.
25:24They adapted for survival by becoming massively large.
25:25This gave them the power to repel attacks.
25:26They adapted for survival by becoming massively large.
25:27This gave them the power to repel attacks.
25:28They adapted for survival by becoming massively large.
25:29This gave them the power to repel attacks.
25:33From early ancestors weighing only 100 kilograms, they developed into creatures weighing more than
26:02six tons.
26:03But many uncertainties still remain about T-Rex's predecessors.
26:09In 2013, Lowen discovered a fossil that answered some questions.
26:22It's from a previously unknown species of Tyrannosaur called Lithronax.
26:29The fossil was buried in soil deposited 80 million years ago, during the evolutionary gap period.
26:37The name we chose, Lithronax, means gore king in ancient Greek.
26:43And we chose this name because Lithronax really was the top predator in its ecosystem.
26:53The fossil indicates that Lithronax measured about eight meters in length.
26:59That represents a remarkable jump in size from Guanlong, its weak ancestor.
27:09This new Tyrannosaur was large enough to battle with the massive Triceratops.
27:14Conditions were ripe for different species to influence one another's evolution.
27:20This phenomenon is known as co-evolution.
27:23So Tyrannosaurs were exploiting these prey species and also undergoing rapid evolution themselves.
27:32So it's really an arms race between the predators and the prey species.
27:36And all of these animals are evolving to have larger body size, both to defend themselves from predators and for the predators to be able to attack the herbivores.
27:50Researchers believe that one factor supporting the Tyrannosaurs' extraordinary growth was a jump in their hunting skills.
27:57Their heads, relatively delicate up to then, widened by about three times.
28:04That made astonishing improvements in eyesight possible.
28:09One of the things that's unique about Lithronax is the fact that it has forward-facing eyes.
28:15Forward-facing eyes occur in modern animals that are predators.
28:20And the ability to have forward-facing eyes allows you to have overlapping field of vision and perceived depth.
28:28So depth perception clearly was possible in this dinosaur and it's something we associate with hunting.
28:39Depth perception makes it possible for a hunter to accurately grasp the distance to its prey.
28:48That would have allowed Tyrannosaurs to catch prey more easily and turn them into much more successful hunters.
28:56They would have gotten plenty of nutrition, enabling massive growth.
29:08These changes culminated in the mightiest dinosaur of all, T-Rex.
29:14By about 80 million years ago, a whole new world of dinosaurs had dawned.
29:20And this was a world that was dominated by the Tyrannosaurs.
29:24They were the biggest predators and they ruled at the top of the food chain.
29:28And these were the Tyrannosaurs that we're all familiar with.
29:31The ones like T-Rex.
29:33The ones that grew so fast that they put on five pounds of weight every day during their teenage years.
29:39And they were utterly in control.
29:41They were the kings of the late Cretaceous.
29:47Overwhelming size wasn't the only result of the Tyrannosaurs' continuous evolution.
29:53Lawrence Whitmer is a paleontologist who has studied the brains of T-Rex.
30:03He's used CT scans of fossils to analyze their brain structure.
30:09The scans point to new developments in sensory faculties.
30:16One thing we saw when we started to reconstruct the brain of T-Rex is that the olfactory bulbs of the brain,
30:28the part of the brain that's involved in processing odors or smells, were really quite enlarged.
30:34What that told us is that the sense of smell was very important for T-Rex.
30:40It was potentially important for locating its prey.
30:44Signals from the sensory organs were sent to and analyzed by the cerebrum.
30:52An index measuring intelligence based on brain-to-body size suggests T-Rex was more advanced relative to other dinosaurs.
31:10The cerebrum, which in mammals like us, is the seat of intelligence and planning and problem solving.
31:21The cerebrum in Tyrannosaurus was actually fairly expanded.
31:26We look at their brain and wonder whether that enlarged cerebrum may have actually had the capacity to be involved in sort of a coordinated group hunting effort.
31:38Such that maybe some animals would actually drive the prey towards other animals, other Tyrannosaurs that were laying in wait.
31:46There he is, T-Rex.
31:58He's not only smarter, but also has a superior sense of smell.
32:04Even in the dark of night, he's able to locate his prey.
32:10Aiding his ability to track game is his keen eyesight.
32:20The Triceratops tries desperately to get away.
32:31But there's another T-Rex waiting for the ambush.
32:40Feasting on kills fueled growth.
32:46The Tyrannosaurs now measured 13 meters.
32:51Their bones grew harder and stronger.
32:54And their bodies were covered in muscles like steel.
33:03Some experts have questioned whether creatures this big have the speed needing to run down prey.
33:08The conventional belief was that T-Rex ran at a speed of 18 kilometers per hour.
33:19That would make it slower than a human.
33:29Tyrannosaurs were thought of as slow and clumsy.
33:32Paleontologist Bill Sellers challenged that view.
33:41So it's very hard when all you've got is bones to try and work out how fast an animal would run.
33:47So what we were trying to do is to come up with evidence from living animals that we could use to work out how fast fossil animals would move.
33:55Sellers and his colleagues looked for present day animals that would approximate the movements of a Tyrannosaur.
34:04They zeroed in on the ostrich.
34:09And these ostriches are as close as we can get in terms of a modern animal that's a bit like a T-Rex.
34:21So they've got two legs, they've got very large bodies and they're high speed runners.
34:26A lot of the basic anatomy is exactly the same.
34:30So they do make a very good model.
34:36Using the ostriches movement as a reference, Sellers made a computer simulation of how a T-Rex might have run.
34:43The model showed which muscles a T-Rex would have used when running.
34:57Sellers took particular notice of the muscles connecting the thighs and the tail.
35:02Sellers took a long time.
35:07Previously, experts thought these muscles were merely for tail movement.
35:12But it became clear that they also played a key role in helping the T-Rex to run fast.
35:20And what it does is it pulls the thigh bone backwards.
35:23And so obviously this is the main powerhouse.
35:26Even though it's a very heavy animal, it can obviously generate the force that it needs to go at a good speed.
35:32With this model, the average T-Rex's top speed increases to 30 kilometers per hour.
35:42And the strongest could run as fast as 50.
35:50The descendants of the primitive Tyrannosaur siblings have acquired speed, size and intelligence.
35:57But there's more.
35:58Carl Bates is an expert on the bite force of dinosaurs.
36:08With an enormous bite force and large neck muscles, it probably clamped onto its prey and pulled away at the flesh.
36:15There have been quite a few fossils found of plant-eating dinosaurs with T-Rex bite marks in them, where the bite marks go very deep into the bones.
36:25A huge jaw powered this deadly bite.
36:30Bates has studied the structure of T-Rex's skull.
36:35He recreated the muscles that connected the upper and lower jaws.
36:45Then he used a computer simulation to quantify the strength of its bite.
36:49Bite force is measured in newtons.
36:50The lion, known as the king of the savannah, has a bite force of 4,000 newtons.
36:54The bite force of alligators, fearsome killers near water, is around 6,000 newtons.
36:59Compare this to the dinosaurs to the dinosaurs.
37:00The allosaurus is considered to have been the strongest dinosaur before T-Rex.
37:02The allosaurus is measured in newtons.
37:03The lion, known as the king of the savannah, has a bite force of 4,000 newtons.
37:08The bite force of alligators, fearsome killers near water, is around 6,000 newtons.
37:22Compare this to the dinosaurs.
37:25The allosaurus is considered to have been the strongest dinosaur before T-Rex.
37:32Its bite force was about 9,000 newtons.
37:41According to Bates, the T-Rex had a bite force of some 60,000 newtons.
37:47That's 7 times greater than the allosaurus.
37:5460,000 newtons is a huge amount of force.
37:57So we're convinced that T-Rex had a very large bite in absolute terms
38:02and was probably one of the fiercest biters of all time.
38:10When a T-Rex bit into its prey, it exerted 6 tons of force.
38:15That's equivalent to the weight of an African elephant.
38:22In theory, such heavy loads could cause the jawbones to break.
38:28But something protected T-Rex from this.
38:34The skull was very important for capturing prey and consuming prey.
38:39We were just interested in how this huge structure performed mechanically.
38:46A T-Rex skull is made up of more than 40 different parts.
38:50Here and there are gaps measuring just a few millimeters.
39:03These gaps released force when the T-Rex bit and helped to soften the shock.
39:08T-Rex has this reputation of being such a deadly fearsome creature.
39:15So we're pretty convinced that T-Rex was one of the most ferocious biters of all time.
39:21And worthy of the title King of the Dinosaurs.
39:23A creature with both extraordinary physical capabilities and sophisticated intelligence.
39:37After 100 million years, T-Rex had reached the pinnacle of its evolution.
39:43A pair of T-Rex siblings.
39:51Even if they were to meet up with Siaj, former ruler of the Dinosaurs.
39:57They would have no reason to flee.
39:59They are no longer the small, weak Tyrannosaurs of old.
40:16The siblings set off on a new journey.
40:33In search of more prey.
40:39They are heading back to the Eurasian continent.
40:46Along the way, they passed through areas inhabited by many relatives from the Tyrannosaur family.
40:57T-Rex was the king of the late Cretaceous, no doubt about that.
41:01But not all Tyrannosaurs that lived at that time were big, top of the food chain predators like T-Rex.
41:08Some of them actually were quite a bit smaller.
41:11So even when T-Rex was ruling the world, there were other close cousins of T-Rex
41:15that were doing other things, filling other roles in the ecosystem, and doing a very good job at it.
41:222014.
41:24In northern Alaska, researchers found a new species of Tyrannosaur.
41:31They called it Nanuxaurus, after the Inuit word for polar bear.
41:35At six meters, it wasn't even half the size of T-Rex.
41:41Experts attribute its small size to a lack of gain.
41:44The same year, in Jiangxi province in southern China, a team dug up an unusual fossil.
41:49The most noticeable feature is its long, thin nose.
41:50It's been nicknamed Pinocchio Rex, in reference to the beloved character.
41:52The most noticeable feature is its long, thin nose.
41:54It's been nicknamed Pinocchio Rex, in reference to the beloved character.
41:55Outwardly, it looks nothing like T-Rex.
41:56But a bone analysis confirmed it as a new Tyrannosaur species.
41:58The same year, in Jiangxi province in southern China, a team dug up an unusual fossil.
42:04The most noticeable feature is its long, thin nose.
42:09It's been nicknamed Pinocchio Rex, in reference to the beloved character.
42:13Outwardly, it looks nothing like T-Rex, but a bone analysis confirmed it as a new Tyrannosaur species.
42:30Then, in July 2015, scientists made a discovery in Japan.
42:36Up until then, no one thought large Tyrannosaurs had lived there.
42:42The team found fossils of two large teeth, each measuring 8 cm.
42:51Their size suggests they came from an animal 10 m long.
42:59Finds like these illustrate the distinctive evolutionary paths taken by Tyrannosaurs all over the world.
43:06So far, experts have identified 28 individual species.
43:20At one point, T-Rex truly dominated the dinosaur world.
43:26But in the end, it would meet a cruel fate.
43:29Evidence of this emerged in 2015.
43:37Scientists were excavating in Alberta province in Western Canada.
43:42They found this fossil, a cousin of T-Rex, called Daspletosaurus.
43:49Here and there, researchers spotted tell-tale signs of battle.
43:57A wound, deep enough to pierce the bone.
44:01On the back of the skull, a part had been bitten off.
44:11Scientists wondered what kind of creature could have inflicted such wounds on the mighty Tyrannosaur.
44:21Palaeontologist David Hohn points to an unlikely suspect.
44:32So you immediately have only one credible candidate for these kinds of injuries and these kinds of bites.
44:39And that's another large-bodied Tyrannosaur.
44:41Hohn says the shape and size of the bite marks indicate a fight between two members of the Tyrannosaur family.
44:51They're going to hunt at the same time of day, in the same place, and have similar territories.
44:58And they're going to come into these conflicts.
45:01I'm sure every so often there were fights to the death.
45:03And certainly we actually see evidence of cannibalism among Tyrannosaurs.
45:07They do kill each other.
45:08In turf battles, even siblings could become rivals.
45:16And if one refused to back down.
45:19Mr. Dormo.
45:28Mr. Dormo.
45:41Mr. Dormo.
45:42Two frail T-Rex ancestors set out on a grand journey in search of new lands.
45:55On the North American continent, they confronted countless threats.
46:05But they managed to thrive.
46:20Their descendants continued to evolve, eventually becoming the undisputed rulers of the dinosaurs.
46:35But once at a time, these powerful killers turned their awesome power on one another.
47:05Sixty-six million years ago, the reign of the dinosaurs came to a sudden end.
47:22Experts believe the reason was a gigantic asteroid that smashed into Earth.
47:34Resulting climate change wiped out the dinosaurs, including Tyrannosaurus.
47:40But was that really the end of the dinosaurs?
47:58Stephen Brussati's research provides evidence that it wasn't.
48:17Certain creatures alive today are descended from a branch of the Tyrannosaur family.
48:25Birds.
48:30Once the dinosaurs died out, birds underwent a spectacular evolution.
48:35New species appeared and they became the rulers of the skies.
48:43They were able to do this because of strengths they inherited from their Tyrannosaur ancestors.
48:48We always talk about dinosaurs going extinct 66 million years ago when the asteroid hit.
48:58But really not all dinosaurs went extinct.
49:00Most of them did.
49:01But one type of dinosaur survived.
49:03And those are the birds.
49:05So birds evolved from dinosaurs.
49:07And they're actually a type of dinosaur.
49:09And they live on today.
49:11There's over 10,000 species of birds.
49:13There's birds flying around here.
49:15And so these birds are living dinosaurs.
49:18And so birds today carry on the genes of T-Rex.
49:26Creatures unlike any seen before or since.
49:30The free spirit of T-Rex lives on.
49:35Transcription by CastingWords
50:05CastingWords
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