Documentary, Walking with Dinosaurs: The Ballad of Big Al, Special 2001
#AncientEarth #Documentary #Dinosaurs #Prehistoric #Evolutionary
#AncientEarth #Documentary #Dinosaurs #Prehistoric #Evolutionary
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00:30All that we have left today of the mighty dinosaurs are their fossils, stone copies of long-dead bones.
00:46It is easy to forget that these were once living animals, surviving in a world of unimaginable violence.
01:00But if you know what you are looking for, the signs and scars of life are clear, as in this remarkable Allosaurus skeleton in Wyoming, nicknamed Big Al.
01:10By studying his bones, comparing him with other fossils and modern animals, there is just enough evidence to raise the ghost of Big Al from its 145 million year old grave.
01:30Bit by bit, a story of how he might have lived can be pieced together.
01:44It is a story that started, like all dinosaurs, with an egg.
01:50Buried in a pile of Jurassic sand is a clutch of eggs.
02:06It is the end of the dry season, and there are signs of life.
02:10This tiny little dinosaur is facing the first of life's challenges, escaping his egg chamber.
02:23He calls out for help.
02:25A huge carnivorous Allosaurus hears the squeak of the hatchlings and approaches the nest.
02:43They are at her mercy.
02:49Fortunately, this is their mother.
02:51Smell is important to Allosaurus, and from the moment mother and hatchling smell each other,
02:57they form a bond that is crucial for the hatchling's early survival.
03:04Gently, she uses her huge claws to free them.
03:21This is Big Al's first day.
03:29For now, he can rely on his mother's protection.
03:32But within weeks, he will have to learn to stand on his own two feet.
03:38In seven short years, he could become a gigantic predator like his mother.
03:43But the odds on him surviving that long are low.
03:46Owl has been born into a world dominated by giants.
04:07For a carnivore, no meal comes easy here.
04:11Some prey, like the 30-tonne Apatosaurus, are giant fortresses of flesh,
04:18too large to attack even by fully grown Allosaurus.
04:23Many smaller species rely on lightning-fast speed,
04:27while others, like Stegosaurus, stand and fight with lethal spines.
04:33It is a daunting prospect for this brood of tiny killers.
04:45They will have to learn very fast.
04:47And fighting among themselves is a good way to start.
04:51However, at this size, they are just as likely to be the hunted as the hunters.
05:11A pair of predatory Ornophilestes watch the brood, waiting for their chance.
05:16The mother Allosaurus is 50 times their weight,
05:22so they will not venture too close while she is present.
05:35However, the smell of all these new hatchlings will soon attract other, larger predators.
05:40So, eventually, the mother decides it is time to lead her unruly brood away.
05:46Al's new home is a vast floodplain, which will one day become the badlands of Wyoming,
06:08but for now it is covered in lush conifer forest.
06:10Dinosaurs share this world with a host of other animals, including amphibians and insects.
06:25It is the insects that the infant Allosaurus are after.
06:32Born with sharp little teeth, Al is ready for his first meal.
06:36But even small prey requires skill to catch.
06:41They are either liable to fly away, or worse still, stand and fight.
06:46They are on top of the streets.
06:56Here it is.
07:03Another note is acredita.
07:05A adverse event.
07:08Another note is that has been real.
07:10This'll only be planted on the皮.
07:13Are there any annual firecoules for the fundamentally?
07:14The hatchlings all have a lot to learn.
07:44That evening, the mother abandons her brood while she hunts for food for herself.
07:57She is not the only one on the prowl tonight.
08:01The hatchlings are being watched by another predator.
08:14Mother returns to her station having lost one hatchling.
08:31The victim was not Al, but ironically, the attacker is a year-old Allosaurus.
08:41These youngsters only have a few weeks of protection before the mother's maternal instincts wear off, and she too will view them as fast food.
09:03Al now hunts alone.
09:06Measuring almost three meters, insects are no longer on the menu.
09:10He is looking for dinosaur flesh.
09:14There is a wide choice in this conifer and cycad forest.
09:26A flock of small Othnelia look ideal, but there is a big problem.
09:31A heavily armoured Stegosaurus is working his way through a cycad stand nearby.
09:41The Othnelia feed off the smashed cycads he leaves behind.
09:47This means they are sticking very close to him.
09:54Too close for a small predator to get in between and attack.
10:04A mother Ornitholestes attending her nest mound may prove more promising.
10:10But the small Allosaurus is about to find out he is no match for an overprotective mother.
10:38Nearby, a group of Dryosaurus offers Al one more chance.
11:08Al cannot possibly run down such swift prey.
11:20He needs to learn to ambush.
11:23He has also ended up too near the edge of the forest.
11:33A herd of Apatosaurus are crashing through the outer forest looking for new plant growth.
11:56Not exactly suitable prey for Al.
12:02Back among the trees, Al finally finds something to take the edge off his hunger.
12:07A nearby stagnant pool offers plenty of opportunity to scavenge meat as many dinosaurs have come here to drink and become stuck in its thick mud.
12:27A recent victim is this Stegosaurus that lies where it died of exhaustion, trying to drag itself free.
12:34But dead bodies also attract adult Allosaurus.
12:40This one is large enough to kill Al, but she would prefer a free meal.
12:48Unfortunately, the churned up swamp left by the Stegosaurus is dangerous.
12:53And one of her kind has already become trapped next to the carcass.
12:57Ignoring the danger signals, the new Allosaurus approaches the carcass to feed.
13:10By the time she realizes she is trapped, it is too late.
13:31Al watches from nearby, only escaping the same fate.
13:55Because he has learned to avoid carrion and the large carnivores that it usually attracts.
14:01By evening, two more carcasses lie beside the pond.
14:17This swamp is a natural predator trap.
14:20And before the Stegosaurus finally rots away, numerous more carnivores could fall for its attractions.
14:27The bodies are left to those that can feast here in safety, the flying pterosaurs.
14:33In the middle of Al's Jurassic world,
15:01is a vast salt lake.
15:04Its crystalline white crust formed by the retreat of an ancient sea.
15:09Occasionally, its shores see the movement of herds of dinosaurs.
15:14These are Diplodocus, heading for a nesting site to the south.
15:30It is a grim journey for these mighty creatures, and the heat and lack of drinking water weeds out the weaker animals.
15:37Predators know this. Predators like Al.
15:44He is now five years old, and although he is nine meters long, he is not yet fully grown.
15:53Al is an experienced hunter, but the herd itself presents a formidable barrier to predators.
16:05Still, Al is not the only predator stalking the herd.
16:09They can all smell that one of the Diplodocus is in a very bad way.
16:20The predators are getting impatient.
16:22They need to break up the herd and isolate the weakling.
16:27The
16:56Oh
17:26Oh
17:56The panicked herd has left the sick Diplodocus far behind
18:17The Allosaurus gather for the feast
18:20However, even a sick and exhausted Diplodocus is a fearsome adversary
18:25Built for speed, Al is frequently wounded in such situations
18:41But he cannot afford to let this slow him down
18:43The competition is too intense
18:46The other carnivores hold back
18:51And wait for time and the heat to finish the giant herbivore
18:56After several hours
19:03Heat exhaustion and his illness
19:06Bring the Diplodocus to his knees
19:08The predators finally get their reward
19:17Although there is enough meat here for weeks
19:20There is an urgency in their feeding
19:22The smell of blood will soon bring others
19:25And every Allosaurus wants to eat its fill
19:27Within the hour
19:36A gigantic female Allosaurus appears out of the haze
19:40She is about twice the weight of the other Allosaurus
19:53And four meters longer
19:55Quickly, she establishes her dominance
19:58When predators get to her size
20:01They rarely have to bring down their own food
20:03They just scavenge other kills
20:05Al tries to find a safer place to eat
20:20The floodplains where Al lives are ruled by the seasons
20:43Short periods of heavy rain give way to long months of drought
20:47It is now the end of the wet season
20:50And with the floodwaters still receding
20:52It is a time of plenty for the local dinosaurs
20:55For many it is also a time for mating
21:07This pair of Stegosaurus are about to try what is for them
21:13A very complex process
21:15Al is now six years old
21:25And as a sign of age
21:26The crests over his eyes are now reddening
21:29Sexual maturity is dependent on his size
21:31And at ten meters long
21:33Al is well on the way to being big enough
21:35He is however making the locals at the waterhole nervous
21:46And the smell of blood he brings with him
21:49Is enough to interrupt the amorous Stegosaurus
21:51Away from the lake
22:18Al picks up a new scent
22:20Dung left by a female Allosaurus
22:24Dung left by a female Allosaurus has an immediate effect on Al
22:25And for the first time in his life
22:28He issues a mating call
22:29The female is not far
22:38And picks up the low sounds in his core
22:41She is much larger than Al
22:50He will have to be careful
22:52She is not interested
23:02But Al's inexperience shows
23:05And he gets too close
23:07He is just сказать
23:08And he usable
23:10So
23:11that's
23:11What I am
23:12What I am
23:12He is
23:13What I am
23:14I am
23:16No
23:16No
23:18No
23:18No
23:20No
23:24Al is lucky, although he had a torn arm, ripped claw and smashed ribs, he has escaped having
23:47his throat torn out.
23:54After five months, the dry season begins to bite.
24:04The sick and the old are being weeded out.
24:07This is good news for scavengers.
24:13This carcass is dried hard, and the pterosaur burrows deeper to find softer meat, but it
24:19is never safe to become too preoccupied.
24:21Al has managed to recover from his fight, although one arm is still not functioning properly.
24:41The pterosaur was not much of a meal, and there is little left on the carcass.
24:47He needs fresh meat.
24:56In the blistering heat, he starts to stalk a flock of swift Dryosaurus.
25:01It will take skill, but he has done this hundreds of times before.
25:08not to be healed.
25:13Don't eat them.
25:18We'll take skill, Verde, to not lose heat.
25:21This door is shot,056.
25:23The thruigor city says thatолж city لا glac formation, which is a force of absorption.
25:28Here's what we see.
25:29The attack is a disaster.
25:41Al has fallen badly.
25:43As he tries to get up, it's clear he has broken something in his right foot.
25:47With prey getting scarcer and scarcer, his chances of survival now look remote.
25:59Two months later, and the drought has continued longer than usual.
26:20It has cost Al dear.
26:23If anything, his limp has got worse.
26:29Because of his poor condition, his body is not healing well.
26:42It appears he broke his middle toe in the fall, and it is now badly infected.
26:51Too weak to hunt. He'll be lucky to survive much longer.
27:00The drought drags on.
27:05A pair of young Allosaurus are out hunting for insects amongst the sand dunes.
27:14Instead, they find something much larger.
27:18The emaciated body of Big Al.
27:21Al never reached his full size.
27:30Instead, he died as a mature adolescent in a dried-up riverbed.
27:35Eventually, the rains would arrive and gently bury his body in silt for 145 million years.
27:41The process preserved his skeleton perfectly.
28:00Including the lumps where his ribs healed after their break.
28:03The raging infection on his middle toe, and at least 17 other injuries and diseases.
28:11In death, Big Al represents a frozen moment in the fast and furious life of a carnivorous dinosaur.
28:18Big Alchemist and Juliet.
28:34The Restoration of the Eve
29:35The Ballad of Big Al was a huge technical challenge, taking over a year to Maine.
29:54But this was nothing compared to the enormous amount of scientific research that inspired the film.
30:02This is the story of how so much is known about one very dead dinosaur.
30:17Scientists are uncovering the remains of an Allosaurus, a dinosaur that...
30:35The excavating team hopes to have Big Al out of the ground by week's end.
30:40We have to very carefully chip away the rock, try to put together the whole story of this animal.
30:44In 1991, out of the rock came a paleontological star, one of the most complete dinosaur skeletons ever found.
30:54He was nicknamed Big Al.
30:56And here we have what a clock from Allosaurus would look like.
31:01So again, this life would be...
31:03After 145 million years, Al's back on his feet again at the University of Wyoming Geological Museum.
31:22But scientists have been able to do more than just rebuild his body.
31:29After extensive forensic analysis of his bones, research into other fossils, and the behavior of his modern relatives...
31:37They know more about Big Al than almost any other dinosaur.
31:48It all adds up to a great paleontological detective story.
31:57Like all good thrillers, the first clues had to be gathered at the scene of the crime.
32:02This is a site in Wyoming where Big Al was discovered in 1991.
32:15And Big Al died 145 million years ago during the late Jurassic period.
32:21And was buried in a river channel deposit that's now part of the Morrison Formation.
32:26Things would have looked a lot different at that time.
32:32It would have been much flatter.
32:35We wouldn't have had any flowering plants.
32:38And in their place we would have had ferns, cycads, even conifers.
32:43At that time, Wyoming was full of dinosaurs.
33:01Most were the lumbering plant-eaters like Diplodocus and the armored Stegosaurus.
33:06Far less common were the carnivores, but this hasn't stopped them becoming infamous, like the Allosaurus.
33:19These fearsome predators were the T-Rex of their day, and Al was one of them.
33:26But like every living thing, these monsters started off small and delicate.
33:37Despite this, science can still tell us something about how Al probably started life.
33:42We're very familiar with how life begins for humans, but you might be surprised to learn how a Jurassic carnivore raises its baby.
33:58Evidence for this comes from remarkable fossils found on the Atlantic coast of Portugal.
34:21It was in this place that we found, in 1993, a small eggshell like this that we figured out there was from a dinosaur.
34:38For the years we have dug it and we found more than 100 eggs that make one of the biggest nests in the world.
34:44But more significantly, they found something which could tell them who these eggs belonged to.
34:53The most rare and sought after fossils of all, tiny preserved bones of baby dinosaurs, still curled up inside their shell.
35:04We have found more than 200 embryonic bones. With them we can say exactly which kind of dinosaur we have.
35:14In this case, it's a meat-eater dinosaur, a carnivore, and we have almost all skeletons here.
35:25And if there were eggs, there must have been a nest.
35:28Bizarrely, there is information about this in the fossilized eggshells themselves.
35:38Under the microscope, scientists can identify holes in the shell.
35:45Their large size allows maximum air for the embryo to breathe,
35:48which tells them that these eggs were buried, packed together in an underground nest.
35:59Scientists know this because there are animals alive today that do the same thing.
36:04The crocodiles.
36:09This is not surprising because crocodiles and alligators are one of the dinosaurs' closest living relatives.
36:15And with scaly skin and a mouthful of teeth, it's easy to see the family resemblance.
36:24But carnivorous dinosaurs have an even closer group of relatives who share some of their other traits.
36:30They are the birds.
36:32Standing on two legs, Big Al's skeleton was actually more like a bird than a crocodile.
36:37But in practice, he was a strange mix of the two.
36:46So after Al hatched, did he feed himself like a crocodile or wait to be fed like most birds?
36:58Evidence found at the site in Portugal provided a clue.
37:02Inside the eggs were found several teeth that are quite rare.
37:07And these teeth, they can tell a lot of things.
37:10For instance, they're born with teeth.
37:12Since they're born, they were able to chew and to eat soft meat, for instance.
37:19Being born with teeth would have made all the difference.
37:24Although they were too small to tear up chunks off his mother's dinner plate,
37:28they were probably perfect for capturing insects.
37:31Just like baby crocodiles, it seems Al was able to fend for himself from an early age.
37:36But Al's biggest problem at this stage in his life was being eaten by a bigger dinosaur.
37:56His only defence was to grow up fast.
37:58And an amazing collection of Allosaurus bones shows just how quickly a baby dinosaur could grow.
38:08What we have here are Allosaurus thigh bones.
38:11And what's unique is the fact that they're going from very, very small to very, very large.
38:16And if we take this smallest bone here, we can see that it's about 18 centimeters in length.
38:25And it would probably belong to a dinosaur that was maybe a meter and a half in length
38:29and possibly stood off of the ground about a meter or so.
38:35If we look at this larger bone over here, this sub-adult,
38:39we probably will have an animal close to eight meters in length.
38:44This bone itself being about a meter in length and probably stood off the ground about two and a half meters.
38:51As we look at Allosaurus bone, we can make thin sections of it
38:57and then we can compare it to crocodiles and to birds.
39:01As we compare it to birds, we see that there's so much similarity
39:05that we know that Allosaurus probably grew very rapidly like a bird would.
39:09So Al was born like a crocodile but grew like a bird.
39:16Probably reaching full size in just six to eight years.
39:20And by the time a child is just starting school,
39:27Al would already have been a fine physical specimen.
39:30It's the last time I'll play with a dinosaur.
39:47Dinosaurs.
39:48So how did he feed this fantastic growth?
39:53Again, his two living relatives may provide a clue,
39:57but they have very different approaches to eating.
39:59Their strategy in feeding is plenty of time.
40:12That's all they've got is a lot of time to wait for something to make a mistake,
40:17a person or another animal.
40:19It's bite first and then ask questions later.
40:21That's what they do.
40:22They grab something that when it offers the opportunity for it,
40:27such as my leg right now.
40:29Let me move this animal.
40:30She's going to be real testy here.
40:32This is a little female.
40:34Move, girl.
40:38Oh, now here's a great opportunity to see a basic difference between a bird and an alligator.
40:44What we see is how a bird is choosing to feed.
40:46The great part is, is anytime you see a bird like this feeding,
40:50is it can actually take and pick out its food amongst the twigs and sticks and other pebbles and things here.
40:56It selectively picks them up and swallows them.
40:58An alligator, on the other hand, will strike at anything it sees.
41:05What we're going to try to do here is trick these alligators into coming after the dinosaur down here.
41:11See, they don't really care what it is they're grabbing.
41:14They're opportunic eaters.
41:16They see something, they perceive it as a food item, and they go for it.
41:23The alligators use their excellent sense of smell to track down their prey.
41:28And dipped in fish oil, even the inedible toy seems tempting.
41:33In fact, the differences between the bird and the alligator's behaviour is reflected in the shape of their brain.
41:51A look inside Al's head could provide direct evidence of his behaviour.
41:58And although Allosaurus are long dead, a remarkable fossil has let scientists do just that.
42:04It's a brain, cast from the inside of an Allosaurus skull.
42:08How does this compare with his relatives?
42:10Well, let's start with a bird.
42:13Here's a model of a bird.
42:15If we look at the way the bird is, we find out that a bird has a very large region that's dedicated to processing information,
42:23and a very small region dedicated to sensory input, such as smelling something.
42:29Well, what about an alligator?
42:30If we take the alligator brain and compare that to Allosaurus, we see something that looks very, very similar.
42:37This is sensory information that comes in here, and then goes to a region that's actually rather small for processing that information.
42:45And it snaps at it.
42:46So it just strikes and hits whatever smells right.
42:51That compares extremely well with Allosaurus.
42:53Therefore, these features tell us that if we want to compare Allosaurus to a modern-day animal, that would be an alligator,
43:03because their brains resemble each other very, very much.
43:06Consequently, their behaviours must have been very similar.
43:08There is an extraordinary and baffling site in Utah that might just bear witness to this sort of feeding behaviour.
43:26Cleveland Lloyd Dinosaur Quarry.
43:30Over 10,000 dinosaur bones have been found jumbled together at this one site.
43:38But as the different bones were identified, something strange emerged.
43:43They found hundreds and hundreds of Allosaurus bones, and just a few of the plant-eating dinosaurs.
43:50The total opposite of what you would expect.
43:53It was a mystery why the predators outnumbered their prey.
43:57What might have happened here is the fact that we have a bog area that collects small pools of water
44:05that would attract Stegosaurus and some other animals that would be prey for the Allosaurus.
44:10And they would get stuck in the mud and might be there for days.
44:14They might stink.
44:16They might be very attractive to an Allosaurus that would be glad to jump in there,
44:21not realizing that they would become entombed themselves, just like their prey.
44:25The Allosaurus were probably led to their death by their noses.
44:37They couldn't ignore the stinking attraction of a carcass.
44:40What probably happened is, when the dinosaurs got into the bog, there was a lot of dinosaur bioturbation,
44:52or a lot of dinosaurs mixing up a lot of the mud.
44:55Hence, we have a huge, huge column of bones that goes quite deep, and they're all mixed up.
45:00The remains of at least 44 Allosaurus were found at this one site.
45:06It looks like this was a natural predator trap.
45:09So Al's brain was probably something like an alligator's.
45:20They lie in wait for a meal to come to them.
45:23But Al's body was built differently.
45:26He looked more like a bird, and they don't hang around for food to wander by.
45:30Just like the brain, these two different lifestyles leave their mark, not only on the skeleton, but on the body's internal organs.
45:45Ostrich tend to be able to run great distances and keep speed and activity up all day long, and they have to do that so that they can gather their food.
45:57To help them do that, they have a heart that delivers oxygen very efficiently to all the tissues of the body after it's gone to the lungs.
46:05Crocodiles, on the other hand, really sit and sneak and kind of wait for prey to come up to them.
46:11They can move very quickly for a short time, but their heart and the way their blood works and their tissues work don't allow them to sustain energy for a long period of time.
46:26Nowadays, to find out how a heart works, medicine has invented machines for scientists to see inside the body.
46:33At the North Carolina College of Veterinary Medicine, an alligator is due for a CT scan.
46:45To prevent him injuring himself or the team, his eyes are taped over and his arms and legs restrained.
46:50This is an alligator straitjacket.
46:56That would be good.
46:59To help relax the alligator, a bizarre form of hypnosis is used.
47:03We're just putting him to sleep by stroking his belly.
47:09It helps an awful lot that he has all the tape on so that we can get to his belly, but this actually works.
47:15Go to sleep.
47:20Nothing happening.
47:21OK, Paul, turn the lights out so we can see the guidelines and let's get him set up.
47:28Start there.
47:30The images on the screen show a cross section through the alligator's chest.
47:35And with each new scan, they are building up a picture of the structure of the heart.
47:38However, until recently, there was little point in doing this to a fossil, because soft tissues don't normally fossilize.
47:49With skeletons like Big Al, scientists could only speculate on what was inside a dinosaur's chest.
48:00But this year, a highly controversial find may have changed all that.
48:05This is an absolutely superb specimen of a small, plant-eating dinosaur.
48:12We call it Thessalosaurus in paleontology, but here at the museum we like to call it Willow, the little dinosaur with a heart.
48:19And in this region is the actual preservation of structures which demonstrate the presence of a heart.
48:25This structure was so peculiar that my colleagues decided to probe it with an X-ray scan.
48:31To help read Willow's scan, the images inside the alligator's chest provide a guide.
48:38As we move through the thorax, then we're going to see the lung fields.
48:44And then coming up between the two lung fields, we'll start to see a solid mass, and that's the heart.
48:49Shown on the alligator scan as a graphic, the two aortas, or tubes which carry blood around the body, are highlighted.
48:58They lead from the two ventricles of the heart.
49:01This plumbing, although perfect for an alligator, only allows it short bursts of activity.
49:07Inside Willow, the picture appears to be different.
49:14If you look at this three-dimensional reconstruction of Willow's CT scan, we can see right here that the two ventricles are easy to identify.
49:23Highlighted at the bottom of the picture.
49:25Then, look up above the heart base, we see this corrugated structure. That's the single aorta.
49:33If this is a single aorta, it would be remarkable, because it would show that this dinosaur's heart had the potential to power it for the marathon, as well as the sprint, unlike the crocodile's.
49:43Apparently, this little dinosaur had a heart that was more like a bird or a mammal than like a crocodile.
49:52This intriguing fossil is still under scrutiny, but if confirmed, Willow's heart will give a new, more energetic look to the dinosaurs.
50:01If this dinosaur had a heart that looks advanced, then that implies that it also had a high metabolic rate.
50:07And now, instead, there is ample reason to think of these as rather high energy active animals.
50:18With the body of a bird, but being 10 meters long, Al could have run at speeds of up to 30 kilometers per hour.
50:37If there was any doubt whether Al led an active life, there is conclusive evidence written in his very bones.
50:52Rebecca Hanna knows Big Al better than anyone.
50:56She spent much of the last eight years examining every inch of his skeleton.
50:59And her search has revealed that he had over 19 abnormal or injured bones in his body.
51:09It seems that this is an unusually high number for an allosaur to have in comparison to other allosaurs that I've looked at.
51:18Now, what this may mean or suggest is that Big Al may have been more aggressive than other allosaurs,
51:23or he may have actually been just sort of clumsy.
51:32Clumsy or brave, Al's bones reveal a chronology of accidents in the latter years of his life
51:38that made him famous as the dinosaur who lived fast and died young.
51:42Big Al received an injury to this section of his tail probably one to two years before he died.
51:53And the way we can tell that is the amount of rehealing on the bone.
51:58This bone was broken in half and then healed back together.
52:02So there is a little bit of a bulge there where you can see where it was broken and healed back together.
52:06But for the most part, it's looking more like the original bone.
52:14It looks like Al took a nasty knock.
52:23But it obviously didn't slow him down because Rebecca Hanna found out that he was shortly in trouble again.
52:29When I was first studying this bone from the right hand of Big Al, it was unclear what had caused it to look this way.
52:43I knew it was abnormal for some reason.
52:46So what I decided to do was to cut a very thin section to look at the actual bone microstructure.
52:51Well, what I discovered was that this bone was actually fractured right along its length called a longitudinal fracture.
53:01And we can see that under the microscope.
53:04The break runs diagonally through this cross section.
53:08Below it, rows of normal bone lie tightly packed together.
53:12But above it, the bone is more loosely woven, a sure sign it's trying to mend.
53:17The bone was broken by some sort of twisting force.
53:24And this bone was broken after the tailbone injury event.
53:30And we know that based on bone microstructure and also just the look of the bone.
53:33It didn't stop there. Al went on to break four ribs and hurt his backbone, shoulder and pelvis.
53:52Even with all these injuries, Al had to keep going.
53:55But eventually something happened to him that would threaten his life altogether.
54:02It could have been just a careless trip, but it cost him dearly and probably spelled the beginning of the end.
54:21Al's left foot looks normal, but there is a huge amount of abnormal bone growth in the right foot.
54:34This is the most serious problem Big Al had.
54:36It's in the right foot, the third toe.
54:38The infection in this toe bone was very long lived and so it's probably not something that happened right at the time of death.
54:47Big Al probably would have had to have been alive with this infection in the bone for at least six months to a year.
54:54And it probably would have caused this animal a great deal of pain and caused it to limp because you can imagine with this type of inflammation when the bone is usually about that wide, it would have actually been rubbing against these other two toes.
55:09Although Al's injuries didn't kill him instantly, they stopped him hunting and left him struggling to find food and water.
55:25If at this point a drought hit, it would have been enough to tip him over the edge.
55:35One hundred and forty five million years later, it seems enough clues were left to piece together the last few hours of Al's life.
55:43Big Al was found when the tail bones here were on the edge of the hillside and as they excavated further into the hill, they found more tail bones which continued on and connected with the hips, the rest of the backbone and even the skull.
56:00So this is a decay posture that occurs when the ligaments that run along the spine dry out and decay arching the head and tail back over the legs towards each other.
56:17What this tells us is that the animal died and laid out for some period of time.
56:23And we've estimated that Big Al laid out on the surface for a period of a couple of months.
56:36It's possible that Big Al came to this river channel in search of water and usually it had water in it and was a drinking source for him.
56:46But at this point in his life, it was dry. He was afraid to leave it.
56:50Maybe he was so injured he couldn't go great distances for water and was hoping that eventually water would flow down here and he may have actually died of thirst.
56:59When water finally came, it was too late for Al, but ironically, the flood sediments that gently buried him ensured that his bones were beautifully preserved so that 145 million years later, no one would forget him.
57:20Would forget him.
57:21Oh, how I've loved you
57:32Since the day you first told me your name
57:39Yes, I have loved you
57:44Yes, I have loved you
57:46Yes, I have loved you
57:48Thinking you
57:50All the while
57:52Delft the same
57:54Oh, how I loved you
58:01Wanna do
58:03Above the end
58:04You
58:05What you're thinking
58:06Like�
58:07Duper
58:08Say
58:10To
58:11You
58:12See
58:17injustice
58:18Especially
58:19For
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