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Documentary, Planet Dinosaur 3 Last Killers
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AnimalsTranscript
00:00We are living through the golden age of dinosaur discoveries.
00:11From all over the world, a whole new generation of dinosaurs has been revealed.
00:17From the biggest giants and the deadliest killers, to the weird and the wonderful.
00:30From the Arctic, to Africa, from South America to Asia.
00:42Using the latest evidence, for the first time, we have a truly global view of these incredible animals.
01:00In this episode, we explore the last generation of killer dinosaurs.
01:11Carnivores that took killing to a new level.
01:15At the end of the Cretaceous period, 75 million years ago, these hunter killers had spread throughout the globe.
01:25In the southern continents, it was the powerful and muscular Abelisaurus that reigned supreme.
01:35Whereas in the north, it was the famous tyrannosaurs that dominated.
01:4575 million years ago, the dinosaur park formation in Canada was home to two of the largest tyrannosaurs.
01:53The biggest and heaviest was Desplatosaurus.
02:00In 2009, medical scanners were used to look inside the brain cases of these killers.
02:08Of all the dinosaur groups, tyrannosaurs were discovered to have one of the largest areas devoted to smell.
02:15Something that would give them a clear hunting advantage.
02:19Back then, Cretaceous Alberta was a vast coastal river plain covered in forests.
02:31The perfect hunting grounds for Desplatosaurus.
02:35At nine meters and three tons, it's the dominant predator in these forests.
02:42Here, it relies on its acute sense of smell and hearing, as much as its sight to hunt its prey.
02:53Krasmosaurus, a rhino-sized behemoth bristling with defensive horns.
03:09And an opponent befitting a killer like Desplatosaurus.
03:12And an opponent befitting a killer like Desplatosaurus.
03:14A
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03:21R
03:29A
03:31A
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03:38B
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03:40Of all the Tyrannosaurs, T-Rex might be the most famous, but the evolutionary blueprint
04:07for these predators was laid down 10 million years earlier with Desplatosaurus.
04:16Tyrannosaurs' effectiveness as killers is clear from their anatomy.
04:20They're massive, with huge strong skulls and powerful muscular necks.
04:26Forward-facing eyes make tracking moving prey easy.
04:30They've famously short arms, but with these giant Tyrannosaurs it's all about the bite.
04:36They had the most powerful bite of any dinosaur, with teeth that unlike the thin, flesh-tearing
04:44blades of Carnosaurs, are thick and strong, easily able to crush bone and kill.
04:55However, this Desplatosaurus has lost the element of surprise.
05:00The odds are now stacked in the Chasmosaur's favour.
05:01Even the most deadly predators fail more often than they succeed.
05:05The odds are now stacked in the Chasmosaur's favour.
05:12Even the most deadly predators fail more often than they succeed.
05:20Tyrannosaurus appeared locked in a deadly evolutionary arms race with the horned dinosaurs.
05:27As one got bigger, so did the other.
05:31It's a predator-prey relationship that endured for more than 65 million years.
05:41Most striking are the head frills of the horned dinosaurs.
05:46The imposing frill of Chasmosaurus is actually made of thin bone and wouldn't stop the bite
06:06of a Tyrannosaur.
06:08But by making it look much bigger, it had the desired effect.
06:14The horns and frills of these dinosaurs acted as visual deterrents, even if they offered
06:20little physical protection.
06:23It meant that a fully grown Chasmosaurus would usually be safe from most predators.
06:28This Despletosaurus is just a youngster.
06:45Even two Despletosaurus pose little threat.
06:51In 2005, a remarkable discovery was announced.
07:05In the two medicine formations of Montana, a new dig had unearthed something quite extraordinary.
07:12A collection of Despletosaurus fossils, all buried at the same place at the same time.
07:20The implication is that Despletosaurus hunt in gangs.
07:44Tyrannosaurs like Despletosaurus were so successful that by the late Cretaceous,
07:49they were the apex predator across virtually all of North America and Asia.
07:56In Asia, there was Electrosaurus, Alluremus, and Tarbosaurus.
08:02In America, Albertosaurus, Gorgosaurus, Desplatosaurus, and T-Rex.
08:08But moving further north, evidence of Tyrannosaurus becomes increasingly rare.
08:15In Alaska, fossils have been excavated close to the Arctic Ocean.
08:21It's the richest source of dinosaurs that lived in the polar regions.
08:26And it seems, here, a different type of killer dominated.
08:37The most common plant eater in this region is the highly social Edmontosaurus.
08:43They're the largest duck-billed dinosaur in North America.
08:56And they are the perfect prey for a very different type of predator.
09:08Trudon may not look as lethal as a Tyrannosaur,
09:11but fossil evidence suggests that these, too, were deadly hunters,
09:15surviving entirely on a diet of meat.
09:18At first sight, it appears the adult Edmontosaurus have little to fear.
09:29Twelve meters in length and weighing three and a half tons,
09:33they physically dwarf this diminutive predator.
09:35Trudon were usually small, two-meter dinosaurs.
09:42But the teeth from the Alaskan Trudon showed something remarkable.
09:48These Arctic predators were almost twice as big as normal.
09:53Trudon not only survived here, they positively thrived.
10:00And that's because their hunting prowess comes into its own after sunset.
10:09This is a land where, after late summer, there are more hours of darkness than light.
10:23Trudon famously have the largest brains relative to their body size of any dinosaur.
10:46Although what appears more important are their eyes.
10:57Not only are they forward-facing, making them active hunters,
11:01but they are exceptionally large.
11:05These are predators that can hunt equally well after dark.
11:18Although the group offers protection,
11:21predators always choose the easiest prey.
11:24So it's the juvenile Edmontosaurs that are at risk.
11:28that is because of the
11:35tends to land or Jacobson.
11:41What do you think?!
11:51They now go after that 때는
11:54Let's do it!
12:03Separated from the group, this youngster has made a dangerous mistake.
12:24The
12:28The
12:34The
12:38The
12:44The
12:50The Alaskan dinosaur bonebeds are dominated by juvenile Edmontosaurus remains.
13:02Some show clear evidence of Trudon bite marks.
13:07It seems, despite its small size, Trudon thrived here by exploiting the vulnerability of the juveniles throughout the long, dark winter months.
13:20With a steady food supply, it means Trudon can survive the harsh arctic winters.
13:35And in doing so, grew to almost double the size of their cousins further south.
13:41But these were the exception.
13:45Wherever else Tyrannosaurs lived, they were the largest predator, living in groups that consist of both youngsters and adults.
13:58In these deadly packs, youngsters provide the speed, adults the power.
14:17It's a hunting strategy that they use to deadly effect.
14:47But despite appearances, this mob attack isn't carefully planned.
15:07There is no strategy behind the actions of the gang.
15:10It's merely opportunism.
15:13And when the kill has been made, the next battle soon begins.
15:17In many Tyrannosaurs, we find holes and gouges on the skulls.
15:35Injuries which turn out to be bite marks, made by other Tyrannosaurs.
15:40In one Desplatosaurus fossil, the tooth marks indicate that an individual had been subject to several attacks.
15:47In another, the tip of a tooth was left embedded in the bone of its skull.
15:54From this evidence, we can assume that such groups were far from harmonious.
16:01And they certainly aren't democratic.
16:08In this world, the strongest takes all.
16:20Tyrannosaurs' domination of the globe might have been total, had it not been, for a strange quirk in the arrangement of the continents.
16:27Seventy-five million years ago, the planet had a clear north-south divide, with no physical link between the parts of the globe.
16:38It meant the Tyrannosaurs couldn't spread to the southern continents.
16:43Here, a different type of killer reigns supreme.
16:50These were abelosaurids.
16:51In the last ten years, Madagascar has provided the most comprehensive evidence about these predators.
17:06Seventy million years ago, Madagascar was already an island.
17:10But its climate was much hotter and drier than today.
17:24In the Cretaceous period, Madagascar was subject to devastating droughts.
17:30And big predators like Majungasaurus are especially vulnerable to starvation.
17:35Scavenging is the only way to survive.
17:44We thought Majungasaurus was the top predator here.
17:49But then, in 2003, some bones of a number of Majungasaurus were reported gouged with teeth marks.
17:56It appeared there was a bigger, more brutal killer at large.
18:04Majungasaurus also shares the plains with smaller dinosaurs like Rafa Narvis.
18:10Rafa Narvis.
18:11Rafa Narvis.
18:17Mjungasaurus also shares the plains with smaller dinosaurs like Rafa Narvis.
18:23Rafa Narvis.
18:25Rafa Narvis.
18:26Being smaller means Rahonavis needs less food to survive.
18:56A carcass will attract every big predator for miles around.
19:20A male Majongasaurus attracted to the feast.
19:28It is more than capable of challenging for the carcass.
19:38A male Majongasaurus is more than capable of challenging for the carcass.
19:48A male Majongasaurus is more than capable of challenging for the carcass.
19:54A male Majongasaurus is more than capable of challenging for the carcass.
20:12Majungasaurus has short arms and can't grasp.
20:38Like Tyrannosaurus, it's all about the bite.
20:49The shape of Majungasaurus skull and teeth suggests a very different biting style to the flesh-tearing
20:55dinosaurs.
20:57With a broad, short and muscular skull, it was a dino better adapted to biting and gripping
21:04rather than slashing its prey.
21:09This fight is about more than just winning the feeding rights to a carcass.
21:13When the bite marks on the Morgasaurus
21:41When the bite marks on the mauled Majungasaurus remains were studied more closely, the marks
21:49on the bones were found to match the only large carnivore in the region.
21:55There is no bigger killer in these lands than Majungasaurus.
21:59This is the first infutable evidence of dinosaur cannibalism.
22:07It might seem shocking, but it's a behavior that clearly shows the most successful killers
22:12of the Morgasaurus.
22:13The Morgasaurus will exploit any situation to their maximum advantage.
22:19TASPLETOSAURUS with a bite force unmatched by any other dinosaur in the region.
22:41These are killers in a completely different league.
23:06This group have congregated to take advantage of an annual event.
23:13In Dinosaur Provincial Park, thousands of bones have been discovered scattered across
23:18the same rock layer.
23:21They belong to the horned dinosaur Centrosaurus.
23:27And they appear to be the bone beds of vast killing fields, sites of wholesale slaughter.
23:46This vast herd of Centrosaurus are on the move.
23:51From their nesting sites on coastal lowlands to the east, unwittingly they are moving towards
23:59almost certain death.
24:04Seasonal monsoons drive the Centrosaurus inland away from coastal flooding.
24:09Seasonal monsoons drive the Centrosaurus in the region.
24:23It's what the Desplatosaurus have been waiting for.
24:26Seasonal monsoons drive the Centrosaurus in the region.
24:33Seasonal monsoons drive the Centrosaurus in the region.
24:38Seasonal monsoons are over again.
24:44Herding behaviour protects the many, but at the expense of the few.
25:03And things are about to get worse for the centrosaurs.
25:33With a flooded river ahead, and the Desplatosaurus behind, the stage is now set for a massacre.
25:54But despite the rich pickings, it's not the Desplatosaurus that are responsible for the
25:59scale of the slaughter.
26:03There's an even more deadly killer at work here.
26:23Severe monsoon rains have transformed shallow rivers into lethal torrents.
26:37And there's an even more of this.
26:49The real killer is the weather itself.
27:19Recent studies of this dense bone bed indicate that 96% of the bones are of a single species,
27:34Centrosaurus, and relatively few of the bones display any bite marks.
27:40The fossil evidence suggests that this was a mass drowning, the result of widespread
27:46seasonal flooding, an event that we have seen repeated in over 20 different sites.
28:02And when the waters recede, new opportunities emerge.
28:09Events like these provide easy pickings for predators.
28:15But even in the fight for rotting flesh, Descretosaurus authority is absolute.
28:23Tyrannosaurs in the north and Abelisaurus in the south were the supreme killers of their
28:29age.
28:32They dominated every continent where they were found.
28:41And together, they were the last of the killer dinosaurs.
28:48And actually, the small詞.
28:53They were the last of the killer dinosaurs.
28:54Even the animation was really used to be a place of bullpen.
28:55And now, we're going to find some more animals that are in the middle of the tournament.
28:58And now, I will understand, I'm aware that most of them are very, very, very high.
29:00And now, I was just having a bit of an education.
29:02And now I will be able to be able to find a way to the world of science.
29:04And now, I'll be able to find a way to find a way that we have to learn more.
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