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Documentary, PaleoWorld PaeoWord S01E02 - Camosaurs
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00:04For most of the dinosaur era, fast, vicious, deadly, flesh-eating predators were no larger
00:10than tigers. Then came a fiendish new strategy for survival. Dinosaurs began to grow, some
00:18as big as a building. Huge, monstrous and overpowering, they were become known as the
00:25great dinosaurus.
01:04The Badlands of Alberta, Canada, are thousands of square miles of nothing but scrub brush
01:09and sand. Yet this place is a gold mine for paleontologists. The landscape is riddled with
01:17fossils, including those of the most terrible land animals that ever lived.
01:37Here more than 500 dinosaur skeletons have been discovered. 75 million years ago, this
01:45was a coastal plain, close to the sea and lush with plant life.
01:53For most of the dinosaur era, which began 245 million years ago, predators remained no larger
02:00than today's land animals. The forces that would eventually drive evolution had yet to emerge.
02:11The continents were knitted together into a single landmass called Pangaea. The climate
02:20was warm and dry. Dinosaurs roamed freely. Then, 200 million years ago, Pangaea broke apart.
02:40Isolating dinosaur populations and creating a revolution in their development. Some plant-eating
02:54dinosaurs grew enormous. To survive, the dinosaurs that preyed on them had to grow too. As much
03:14planet was in the world, which is 30 times larger. And they perfected their arsenal of
03:23weapons. These were the connoisseurs, the general name given to large meat-eating dinosaurs. At
03:40least 15 feet long, they walked upright on two legs, had large heads, dagger-like teeth, and
03:46very short arms. These are the killer dinosaurs every child loves and the mainstay of old science
03:59fiction movies. Their modern reconstructions draw thousands to theme parks. Their bodies as big as
04:24the world's buildings. Their steps made the earth tremble as they chased their prey and tore it apart with their
04:34powerful jaws. Some of the first examples of connoisseurs were found in Alberta's Badlands. Embedded in stone, dead for at
04:54least
04:5475 million years. Albertosaurus is a member of the most highly evolved, the most fearsome, and deadly
05:01connoisseur family of them all, the tyrannosaurs. Its killer cousin is perhaps the best known dinosaur of them all,
05:10tyrannosaurus rex. Here in Dinosaur Provincial Park, Phil Curry and his team from Canada's Royal Tyrell Museum have just uncovered
05:30the remains of a killer.
05:32This quarry was only opened three days ago, but enough has been exposed already that we can
05:37identify what kind of dinosaur it is. If we look at this rib, for example, we can see the head.
05:43In front of the rib are a number of very slender bones,
05:48which are called gastralia, and gastralia are special bones that cover the belly region of tyrannosaur dinosaurs. And from the
05:57size of these gastralia and the shape we can tell that this is a tyrannosaurid.
06:02This is a vertebra from the trunk region, and just being uncovered right now are a series of vertebrae from
06:11the neck. And again, these confirm that this is a tyrannosaurid.
06:15We think at this point in time that this is probably a half-grown albertosaurus.
06:21Curry and his team are covering albertosaurus with a plaster cast so it can be transported safely back to the
06:27lab for examination.
06:30Like all connoisseurs, albertosaurus used its massive head as a weapon.
06:36Its jaw was longer and its teeth bigger than earlier predatory dinosaurs.
06:41This extra equipment would have made the skull heavy, but nature is ingenious.
06:46The skull acquired holes and its bones were hollow, but critical stress points within the skull were heavily reinforced.
06:56Albertosaurus was the size of a small bus and weighed two and a half tons.
07:01It had a thin build with a pointed snout and a severe overbite.
07:07Paleontologists used to think connoisseurs were slow, lumbering creatures, just overgrown alligators and crocodiles.
07:13Some suggest they were even too big to hunt and depended instead on scavenging.
07:20But Curry believes that based on the footprints of smaller predatory dinosaurs with similar leg structures,
07:26connoisseurs were in fact swift and agile.
07:30For example, an ornithomimid, one of the fastest dinosaurs known,
07:36when it was walking would take fairly short steps.
07:40But as it moved faster, those steps would increase greatly.
07:46And by measuring the distance between two left footprints or two right footprints,
07:53and the length of the foot itself, we can calculate how fast those animals were moving.
07:59From his studies of ancient footprints left in mud, Curry estimated the six-foot-tall dinosaur moved about 15 miles
08:07an hour.
08:08When it wasn't hampered by mud, it could probably run much faster.
08:14Albertosaurus and the other connoisseurs were probably not as fast,
08:17though most paleontologists agree they could outrun a human.
08:22Some estimate they could move up to 40 miles an hour.
08:25Just in speed and size alone, these were terrifying creatures.
08:28But it was their arsenal of killing tools, including their jaws and powerful necks, that inspires awe.
08:38Most think of dinosaurs as giant creatures, but many were quite small.
08:41It wasn't until the end of the Cretaceous era, 65 million years ago, that the giants truly emerged.
08:50Their rise to dominance was destined 200 million years ago, when the supercontinent of Pangea broke in two.
08:58The newly forming mountain ranges of inland seaways isolated the dinosaurs into smaller and smaller groups.
09:06This geographic isolation is the primary event that makes evolution work.
09:11It allows for greater diversity.
09:15As the land masses drifted apart, both plants and animals began adapting to their new environments by evolving a variety
09:21of strategies for survival.
09:24Among the plant-eaters, ankylosaurs developed heavy armor and a club tail.
09:33Triceratops evolved shields and enormous horns.
09:37And the seismosaurus simply grew huge, as big as five elephants.
09:41The largest animal ever to walk the earth.
09:46In the game of survival, size proved to be a successful strategy.
09:51But when sheer size wasn't enough, some plant-eaters found safety in numbers.
09:58They formed herds for additional protection.
10:03To keep up with their prey, meat-eating dinosaurs grew larger as well.
10:07But size wasn't enough.
10:09To maintain their advantage, they had to be smarter and faster.
10:12If they weren't, they would starve.
10:19We know that whenever there's a major change from one group of animals into another group of animals, it usually
10:25happens in the meat-eating animals, not in the plant-eating animals.
10:29There's a lot of reasons for this.
10:31But generally, we find that within a group, there's an influence between the meat-eaters and the plant-eaters.
10:37The plant-eaters are trying to get bigger and better arms so that they can protect themselves better against the
10:42meat-eaters.
10:43But the meat-eaters have to stay ahead in that arms race.
10:45They always have to be a little bit more intelligent and a little bit more faster, because if they're not,
10:49they won't eat.
10:52The basic strategies of carnosaurs and their plant-eating prey were similar throughout the world.
11:05But in geographic isolation, curious physical changes were in store.
11:16One place to investigate these changes is Argentina.
11:25Here, new and unusual connoisseurs are being found.
11:34In the past, most dinosaur fossils were unearthed in the northern hemisphere where paleontology originated,
11:40and fossils were easily located.
11:52Because of the long period of isolation between the two supercontinents, when a new dinosaur is discovered in South America,
11:59it often has novel features.
12:04Jose Bonaparte of Argentina's National Museum of Natural Science in Buenos Aires has been called the Master of the Mesozoic.
12:13He has studied dinosaurs in Argentina for three decades, longer than anyone else.
12:20In 1985, Dr. Bonaparte discovered a one-ton meat-eating dinosaur called Carnotaurus.
12:33His find surprised paleontologists.
12:38Carnotaurus appeared shortly after the continent split apart.
12:43The skull was very tall for its length and strongly built.
12:48But its most unusual feature is the two large flat horns jutting out over its eyes.
12:57Carnotaurus usually have very small horns, if any at all.
13:02This skull, as you say, is very unusual for a carnivorous dinosaur, because it is provided with very large horns.
13:12We understand that this horn helps the animal for killing the prey, because the forearms of this animal are very
13:22much reduced.
13:24The back of the skull was designed to anchor powerful neck and jaw muscles, the hallmark of connoisseurs.
13:33While many of the early predators killed by slashing with claws on their feet, the connoisseurs developed huge sledgehammer heads
13:40and jaws so powerful they could easily rip through bone and armor plate.
13:49The mouths of many connoisseurs had a special hinge that allowed them to open wider.
13:56Carnotaurus had a hinge that enabled it to widen its mouth sideways as well.
14:03It was adapted for taking especially large bites, as large as 100 pounds a mouthful.
14:10This articulation enabled the animal to widen the mouth, to make this movement.
14:16And this movement helped for swallowing big pieces of meat, because the animal was able to widen the lower jaw
14:26in this part that is the place for the swallowing of the piece.
14:34Carnotaurus puzzle scientist. Despite its huge jaw muscles, its lower jaw is half that of a T-Rex of similar
14:41size, and its teeth are more slender.
14:46Also, Carnotaurus is significantly smaller than the giants that evolved later, such as Allosaurus, Spinosaurus, and T-Rex.
14:57And yet, Carnotaurus is the largest predator ever found in South America, and clearly the dominant animal.
15:05Its slender lower jaw may not have mattered.
15:10It could kill and eat anything it wanted, and it had no enemies.
15:16The connoisseurs that came after would further perfect body structures to become truly remarkable killing machines.
15:30As paleontologists expand their southward search for fossils, they are discovering connoisseurs that are strikingly different from those previously known.
15:47One of the oldest giant connoisseurs was found here, just 400 miles from the South Pole.
15:56In 1991, a geologist working in the area discovered a fragment of bone, luring paleontologists to the frozen wasteland to
16:05investigate.
16:09During the dig, the temperature never rose above 25 degrees below zero.
16:15Diggers moved 5,000 pounds of rock to free their amazing find.
16:21Cryolophosaurus, the frozen, crested dinosaur, was a 25-foot-long flesh-eater.
16:28It is the first dinosaur to be unearthed in Antarctica.
16:32At 190 million years, it is also one of the oldest connoisseurs ever discovered.
16:42Paleontologist William Hammer of Augustana College in Illinois led the dig.
16:47So, this is the eye, this is the top of the head right here, and these are ridges, long narrow
16:53ridges that run along the top of the head from where the nose would be, back to above the eye,
16:59and then these ridges merge in the middle and form a very large crest.
17:05And this is the most unique thing about the skull, this crest.
17:10Its crest was most likely used for display purposes during courtship, like a peacock's tail.
17:17Although other connoisseurs had some type of headgear,
17:21Cryolophosaurus was significantly larger and too fragile for fighting.
17:26When Hammer began to separate it from the rock, he and his team made another discovery.
17:32They had found not one dinosaur, but two.
17:36It seems Cryolophosaurus was devouring a large plant-eating dinosaur called a prosauropod when it died.
17:45Well, it seems that this animal was eating another one when it died.
17:50In fact, it might have even choked on the ribs of a plant-eater.
17:53There are two ribs from another plant-eating prosauropod here in the mouth.
17:58They start here behind, in the back of the skull, you can see them going right down all the way
18:04into the mouth between the jaws here.
18:05This is the back end of the skull, right below where the vertebral column, or the backbone, would attach.
18:11And you can see two ribs going down, and you can follow them all the way down into the mouth,
18:14right between the jaws.
18:15And these are the lower jaws here, and this was broken off.
18:19It would extend all the way out, had we, the rest of the skull.
18:24With the discovery of the Cryolophosaurus, science can now trace the evolution of the connoisseur back almost 200 million years
18:30to the Jurassic period.
18:33The reduced arms, sledgehammer head, and steel-trapped jaws would continue to be refined over 135 million years,
18:41until an animal would evolve whose every feature down to the core of its bones was created solely for killing.
19:06As the large connoisseurs, such as T-Rex, became more efficient at the end of the Cretaceous, they forced out
19:12all other predators.
19:14They became the sole large flesh-eaters.
19:19Phil Curry believes these evolutionary changes were beginning to snowball.
19:25But towards the end, during the Cretaceous, we're seeing an acceleration in diversification,
19:30and greater and greater changes taking place.
19:33So it appears that things were evolving very slowly initially.
19:38But towards the end of their reign on the earth, as the king dinosaurs, or the top carnivores,
19:45they were diversifying much more rapidly and changing much more rapidly.
19:54Whether hunting alone or in groups, connoisseurs were deadly.
20:00They would rush in at tremendous speed, scoop out a huge hunk of flesh,
20:04then leap back and wait for their prey to bleed to death.
20:07Risk-free and very effective.
20:14Based on the habits of modern predators, the connoisseurs probably hunted at dawn or dusk,
20:19or on moonlit nights.
20:23They may have only eaten once a week, or even every other week,
20:26but when they ate, it might have been 1,000 pounds at a sitting.
20:33In North America, Albertosaurus and Tyrannosaurus took two evolutionary courses.
20:38Tyrannosaurus took the past track and became larger and stronger.
20:44Albertosaurus remained the same size.
20:46It was quicker than T-Rex, but not as big.
20:51As connoisseurs evolved their fast, long legs and large, meat-scooping jaws,
20:56all else was paired away.
20:59Their arms and shoulders grew smaller, no bigger than a man's.
21:05The reason they developed the short arms is to reduce the amount of weight in front of the hips.
21:11As you get bigger, you end up having more mass in front of the hips,
21:15and if you're a big meat-eating dinosaur, you suffer the possibility that you're going to fall on your face,
21:22if you have too much weight up front.
21:23So what these animals did was reduce the weight as much as possible.
21:28Regardless of the fact that they're very short arms, they are nevertheless quite powerful.
21:33And one would assume that these animals were in fact grasping their prey,
21:37holding onto them while the jaws did their dirty work.
21:43We know how connoisseurs were built, but what did they really look like?
21:48Some speculate they had lizard-like skin.
21:53Others suggest they were more like birds, and perhaps even had feathers.
21:58Now Jose Bonaparte has found the first direct evidence, a skin impression from a connoisseur.
22:05This is interesting because some paleontologists suppose that the carnivorous dinosaur, they had some feathers,
22:14but we have discovered not the slight indication of feather in the skin impression.
22:20Reconstructing the shape of a dinosaur's head is fairly easy.
22:23The heads were mostly skin and bones, so the shape closely matches that of the skull.
22:31The body is more difficult. The skeleton is a clue to its size and bulk.
22:38Probably the most difficult question is what color were they?
22:41The small predators were probably camouflaged with stripes and spots.
22:47But camouflage wouldn't make much difference to a 20-foot-tall killer,
22:51so the biggest connoisseurs were most likely a dull green or grey.
22:59Based on the size of their brain case, the last of the connoisseurs had added a new feature to their
23:04already impressive arsenal of weapons.
23:07Intelligence. It is a characteristic of all pack-hunting animals.
23:14I think that you need a relatively high degree of intelligence to work as a coordinated group, as a packing
23:23animal.
23:24And it's not surprising that most of the most intelligent animals today are, in fact, some of the more intelligent
23:31animals that we're aware of.
23:32So it's not surprising that amongst the dinosaurs, the ones that we think are packing animals are the ones with
23:38the largest brains.
23:40The later connoisseurs' eyes looked forward, giving them depth perception, thus allowing them to strike more accurately.
23:47And they had a highly directional sense of hearing.
23:56At the time of the great dinosaur extinction, 65 million years ago, the great connoisseurs were rapidly diversifying and becoming
24:04increasingly sophisticated.
24:11The pattern for two-legged dinosaurs with big heads and sharp teeth started early in the dinosaur era, and carried
24:19through until they had become the most terrifying and deadly animals ever to walk the earth.
24:28It's a good thing for humans that they went extinct. Otherwise, mammals, including ourselves, might never have evolved.
24:38Yet one wonders, how much further could the connoisseurs have progressed?
24:44What deadly new adaptations might they have evolved?
24:49Could they have become any more frightening?
25:17My andSea Davis
25:18Melissa
25:18Melissa
25:46Transcription by CastingWords
25:58Transcription by CastingWords
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