Clues to human extinction are discovered in the Dinosaur's apocalypse. See more in this special, "First Apocalypse."
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00:00:00We humans believe that we are masters of our own fate.
00:00:04In reality, we are but pawns in the game of life.
00:00:10The previous rulers of our planet, the dinosaurs,
00:00:14reigned for 150 million years,
00:00:17but even they were finally overthrown.
00:00:22Whatever caused their extinction
00:00:24may herald the end of days for our civilization.
00:00:29Did Armageddon arrive in a shocking instant?
00:00:34It is like trillions upon trillions of meteors
00:00:37hitting the atmosphere all at the same time.
00:00:41You would have a poison gas cloud
00:00:43that would spread over the land.
00:00:45Certainly within three months,
00:00:47I'm sure every dinosaur on the planet was dead.
00:00:49Or was it a long, slow death
00:00:51in a perilous and merciless world?
00:00:54The dinosaurs were doomed, whether or not
00:00:57there was an asteroid hitting the Earth.
00:01:00The dinosaurs would have essentially been sitting ducks.
00:01:03It's almost as though dinosaurs were being set up for failure.
00:01:07The answer leads to a stunning conclusion.
00:01:10We have no evidence that any single dinosaur
00:01:13lived long enough to be whacked by the meteorite.
00:01:15None.
00:01:17This you should find deeply disturbing.
00:01:22What you think you know about what caused dinosaur extinction
00:01:25is not the whole story.
00:01:27Reality is much scarier.
00:01:30Past is prologue.
00:01:32The ultimate destiny of mankind
00:01:34reveals itself in the history of...
00:01:37The First Apocalypse.
00:01:5065 million years ago,
00:01:53dinosaurs dominate the planet.
00:01:58If man were alive,
00:02:00he would be prey rather than predator.
00:02:04But severe changes are battering the global environment.
00:02:08They're provoking the natural forces of evolution,
00:02:12helping to knock the dinosaurs from power.
00:02:16Their extinction is just weeks away.
00:02:20This Tyrannosaurus rex, the last of his kind, will die.
00:02:26A mass killing is underway
00:02:28on a scale that our world hasn't seen since.
00:02:31By the time it is over,
00:02:33no creature weighing more than 50 pounds will survive.
00:02:38In the oceans,
00:02:40a wide range of marine organisms ceases to exist.
00:02:44When the horror finally ends,
00:02:46more than half of all the diversity of life on the planet
00:02:49will be extinguished.
00:02:53Most famously, no dinosaurs will survive,
00:02:57not even the mighty T. rex.
00:03:00These were horrendous creatures
00:03:02that suddenly vanished off the face of the Earth.
00:03:10The dinosaurs, though,
00:03:11are not the first victims of a malicious Earth.
00:03:15There have been many others.
00:03:17Most of the species that ever lived on this planet are extinct.
00:03:22From time to time,
00:03:24there are moments in the punctuated history of Earth
00:03:28in which the rates of extinction have accelerated enormously.
00:03:34Those moments are called mass extinction.
00:03:39Scientists recognize five major mass extinction events
00:03:43in the Earth's history,
00:03:45but the one that abolished the dinosaurs
00:03:48may be the most critical.
00:03:50If dinosaurs hadn't become extinct,
00:03:52I don't think we'd be here.
00:03:54It's that simple.
00:03:55This wouldn't be a world dominated by mammals and birds.
00:03:59It'd be a world dominated by dinosaurs.
00:04:02So the extinction of dinosaurs
00:04:04is perhaps the one that affects us the most as humans.
00:04:12The world we live in
00:04:13may already be in the throes of its own mass extinction,
00:04:18a new apocalypse.
00:04:21The past mass extinctions have really shown
00:04:23that species can die in huge numbers,
00:04:25and I think the lesson from them is that
00:04:27our society is as fragile as any number of species
00:04:30and that we should learn that what we have now can change,
00:04:34can change quickly.
00:04:36We humans are not immune.
00:04:39We may be doing stuff to the ecosystem
00:04:42that will kill lots of species and eventually kill us.
00:04:47Human beings may have to face their own extinction.
00:04:52Maybe whatever is out there in the universe is gunning for us.
00:05:01What concerns me is what might destroy our civilization
00:05:07or hurt the Earth so much that life loses a lot of its meaning.
00:05:14The string of events that erase the dinosaurs
00:05:18portends terrifying consequences for human civilization.
00:05:24So what was capable of killing these formidable creatures?
00:05:29At one time, they infiltrated every corner of our planet.
00:05:34They were incredibly diverse and well-adapted animals
00:05:38to just about every environment you can imagine.
00:05:41We have big dinosaurs and we have small dinosaurs
00:05:43and we have dinosaurs with feathers
00:05:45and dinosaurs that were warm-blooded.
00:05:48Scientists have found evidence of an explosive impact
00:05:52formed 65 million years ago
00:05:55and centered in the Gulf of Mexico.
00:05:58Many believe that this is what provoked Dino Armageddon.
00:06:06But perhaps we've overlooked the true murderer.
00:06:09A rogue's gallery of suspects stalk the dinosaur's world.
00:06:13Brutal climates, rampaging disease,
00:06:18and titanic volcanoes among them.
00:06:22For decades, the dominant theory invokes a meteorite,
00:06:27possibly an asteroid or wayward comet.
00:06:31It's headed for an Earth that looks different than it does today.
00:06:35Ocean levels are higher,
00:06:37meaning the meteorite is headed for a splashdown landing
00:06:41in what is today Mexico.
00:06:46Before it arrives, though,
00:06:48it's just another day in the age of dinosaurs 65 million years ago.
00:06:54The fear-mongering predators, like these armor-plated ankylosaurs,
00:06:59are flourishing throughout the continent.
00:07:02Meanwhile, two old rivals,
00:07:05the fear-meat-eating Tyrannosaurus rex
00:07:08and the dangerous horned Triceratops,
00:07:11face off in a death match.
00:07:15Hundreds of miles to the south,
00:07:18an imposing Alamosaurus herd is on the move.
00:07:22Soon, though, their lives will soon end.
00:07:28And then the apocalyptic harbinger appears.
00:07:33A new star-like light blinks on overhead.
00:07:37This seemingly harmless speck is actually a meteor barreling toward Earth,
00:07:42heading directly for the Gulf of Mexico.
00:07:46When it reached the top of the Earth's atmosphere, however,
00:07:49it exploded in light, creating what looks like fire falling from the sky.
00:07:55And of course, if you were that close to have seen that type of process,
00:07:59your life was going to be over in a matter of seconds.
00:08:04You were far too close to survive the initial stages of the impact event.
00:08:10That object was moving in excess of 40,000 miles per hour.
00:08:14When its leading edge touched the surface of the Gulf of Mexico,
00:08:18its trailing edge was still far up in the atmosphere,
00:08:21so it was a mountainous-sized object that was actually larger than Mount Everest.
00:08:27And then, impact.
00:08:34This fateful instant forever alters the future of life on our planet.
00:08:41When that object slammed into Yucatan of Mexico,
00:08:44first there was an instantaneous burst of heat and light traveling at the speed of light.
00:08:50At ground zero, everything vaporizes in a flash.
00:08:56This was an immense amount of energy equivalent to 100 trillion tons of TNT.
00:09:03By some calculations, the impact exploded with a detonation greater than 5 billion atomic bombs.
00:09:12We're not sure, but the best computer projections show that an object perhaps 6 miles across
00:09:19plowed into the Yucatan of Mexico, gouging out a crater of about 180 to 200 miles in diameter.
00:09:28And it was a life-changing event.
00:09:34Rocky debris spews outward from the impact site as far as 400 miles away.
00:09:40Storms of rubble cascade into piles up to 50 feet deep.
00:09:47All life within this range is simply buried alive.
00:09:52A horrifying cracking sound signals that the impact has also incited a vicious shockwave.
00:09:58As it radiates across the landscape, it carries 1,000-mile-per-hour winds in its wake.
00:10:06Not only massive beasts, but also entire forests yield to the shockwave.
00:10:17Because the impact event also occurred in a shallow sea, it created essentially a big splash.
00:10:23And as we all know, when you splash something in the water, you create ripples.
00:10:27In this case, those ripples actually would have grown into tsunamis.
00:10:32Anything near the coast, but out of range of the initial shockwave,
00:10:38soon faces the power of immense walls of water.
00:10:42500-foot-high waves crash into coastlines all around the Gulf of Mexico
00:10:47and drown life for miles inland.
00:10:53As dramatic as those events were, and as devastating as they were for life in the Gulf of Mexico region,
00:11:00they were not what was responsible for the mass extinction.
00:11:04But the asteroid only clunked a few on the head.
00:11:07I mean, how many did the asteroid actually squash?
00:11:10So it is the effects of the asteroid that caused the kill.
00:11:16To understand that, we have to look at what we call
00:11:19the vapor-rich plume of debris that is ejected from the crater.
00:11:24The ejected rock and dust debris screams skyward at 50 times the speed of sound.
00:11:35This vapor-rich plume has so much energy, it actually punches through the Earth's atmosphere,
00:11:39carrying portions of the Earth's crust.
00:11:43Some chunks of Earth even make it to the Moon, or go crashing into other planets.
00:11:48But the rest falls back.
00:11:54That material, however, that does rain back down towards the Earth,
00:11:58begins to envelope the Earth and crashes back into the top of the atmosphere around the entire world.
00:12:06When that happens, it is like trillions upon trillions of meteors
00:12:10hitting the atmosphere all at the same time.
00:12:16The heavens open in a horrible rain of fire.
00:12:19As the meteors fall, the sky gets hotter and hotter.
00:12:23Everything on the surface below suddenly faces the very real possibility of being broiled alive.
00:12:41To understand the after-effects of the impact,
00:12:44geologists visit sites like Trinidad State Park, nestled in southeastern Colorado.
00:12:50Here, we can find physical evidence of the alleged dinosaur killer.
00:12:57The impact mass extinction hypothesis is, I think, one of the most robust hypotheses
00:13:03because it is a testable hypothesis.
00:13:06And in science, that is a very important hypothesis.
00:13:10And here, we can test that idea and extract evidence from the rock record.
00:13:1765 million years ago, this exact spot on Earth was a front-row seat for the end of an age.
00:13:25Scientists refer to the last days of the dinosaurs as the Cretaceous period
00:13:30and call the succeeding age, which includes the rise of man,
00:13:34What is known as the Cretaceous Tertiary, or K-T boundary, divides the two eras.
00:13:42If we take a look at these rocks, we find evidence of dinosaurs
00:13:46and other organisms that occupied their world.
00:13:49In the rocks higher up in this outcrop, we have a material that was deposited during the Tertiary
00:13:55that was used to build the Cretaceous period.
00:13:58In the rocks higher up in this outcrop, we have a material that was deposited during the Tertiary
00:14:04long after dinosaurs were extinguished and the world was a completely different place.
00:14:09Right in between these two units, right at the K-T boundary,
00:14:14we have this very important white strip of rock.
00:14:18This is the K-T boundary rock, and this contains evidence
00:14:23that tells us what happened to extinguish the dinosaurs.
00:14:28Within this thin band here in Colorado,
00:14:31scientists have found bits of extraterrestrial meteorite mixed with pieces of Mexican rock,
00:14:37well over 1,000 miles away from the crater site.
00:14:43Although this part of the dinosaurs' world did not suffer from a direct impact,
00:14:48it did not escape the Grim Reaper's reach.
00:14:52One finds small traces of charcoal and soot,
00:14:56both indications that there were wildfires,
00:14:59and not only elsewhere in the world, but precisely in this part of the world.
00:15:05In addition, the sediments above indicate that the landscape is completely erased of vegetation.
00:15:13There aren't bushes. There are no longer trees.
00:15:17But the sequence of events spelled out by the impact theory may not be revealing the truth,
00:15:23and man's destiny hangs in the balance.
00:15:34Beneath our cities, farms, and forests,
00:15:38etched into the ground we walk on and the mountains above our heads,
00:15:43the remnants of an earthly apocalypse from 65 million years ago haunt humanity.
00:15:51Many scientists believe that the extinction of the dinosaurs began then,
00:15:56in a flash, when a meteorite landed near the Yucatan Peninsula of Mexico.
00:16:14On this day, over a thousand miles away in western North America,
00:16:19duck-billed dinosaurs are feeding,
00:16:22while carnivorous feathered dinosaurs scamper underfoot.
00:16:29Suddenly, the sky above their heads begins to glow.
00:16:35As the leftover debris from the impact re-enters the atmosphere, it heats.
00:16:40Below its trajectory, the temperature jumps a few hundred degrees a minute.
00:16:45It gets hotter than a charcoal grill at full bore.
00:16:51The feathered dinosaurs and duck-bills can't withstand the intensity of the sweltering heat.
00:17:02It actually dries out the vegetation, much like wood in a kiln, and spontaneously ignites it.
00:17:09If you dig right through the surface of the Earth, throughout most of North America,
00:17:14you actually encounter a layer of carbon,
00:17:17perhaps charred ash from the firestorm that hit North America.
00:17:23We now know the ultimate fate of the dinosaurs.
00:17:27They were barbecued by that meteor or comet that slammed into Mexico.
00:17:33Meteor fragments cascade over the planet for four days and four nights.
00:17:38New wildfires spark.
00:17:40By some estimates, half of the world's forests burn to the ground.
00:17:47If you want to actually cause dramatic biological effects,
00:17:50you attack the base of the food chain.
00:17:52On continental regions, if you burn away the vegetation,
00:17:56you've done just that.
00:17:58By some projections, the fires release 10,000 billion tons each
00:18:03of carbon dioxide, carbon monoxide, and methane.
00:18:09That's equivalent to 3,000 years of modern fossil fuel burning in a matter of weeks.
00:18:18Pollution suffocates the atmosphere.
00:18:21When it does rain, it is corrosively acidic,
00:18:24and the world's ecosystems take another hit.
00:18:31Acid rain destroys plant life and poisons lakes, rivers, and ponds.
00:18:36Worldwide, marine plants and animals suffer.
00:18:41The atmosphere above us is now completely choked up by carbon dioxide.
00:18:46Enhanced by soot that's risen from the fires.
00:18:49Enhanced further by the sulfuric acid aerosols that were launched from the impact site.
00:18:56With the sun obscured, Earth plunges into darkness and chills dramatically.
00:19:02The hand of the cosmic killer continues its work
00:19:06as it reaches for the world's dinosaurs' necks.
00:19:10The hand of the cosmic killer continues its work
00:19:14as it reaches for the world's dinosaurs not affected by fire.
00:19:18Those are dinosaurs that wouldn't have been wiped out in the impact event.
00:19:22They would have been sitting there wondering,
00:19:24what the heck's going on with our climate?
00:19:26You know, this year seems unusually cloudy and cold.
00:19:29What's happening here?
00:19:31The world became a very dark place for a period of time.
00:19:34As the darkness persisted, of course, the plants died.
00:19:38And that, in turn, would have affected the animals themselves.
00:19:42If you annihilate the plant communities across vast areas of the landscape,
00:19:46it's like shutting down all the grocery stores.
00:19:49There's nowhere to go to get your fresh fruits and vegetables.
00:19:52With nothing to eat, the herbivores die.
00:19:54When the herbivores are dead, they go to carnivores.
00:19:56So, certainly within three months, I'm sure every dinosaur on the planet was dead.
00:20:02Among the first victims are the largest plant eaters, like Triceratops.
00:20:09The situation is desperate.
00:20:12This Triceratops herd is starving.
00:20:15Many are already dead.
00:20:17The survivors haven't eaten anything for many days.
00:20:21This one is so weak, and its pangs of hunger so intense,
00:20:25it has decided to eat rocks.
00:20:29When faced with starvation, of course, animals can do some pretty amazing things.
00:20:35And I think it's quite evident that a starving animal would eat anything it could
00:20:40to basically make the feeling go away.
00:20:45It's worse for the adolescents.
00:20:47Their growing bodies crave food.
00:20:50They can't go as long as the adults without eating.
00:20:53Worse still, with fewer and fewer young, the entire species is threatened.
00:20:59As their numbers dwindle,
00:21:01the meat eaters that prey on them begin to suffer as well.
00:21:08The largest meat eaters starve first.
00:21:11Less and less prey remains for each individual predator.
00:21:16And with fewer meals to go around, there are fewer predators who can survive.
00:21:24The last T. rex, the rarest predator, dies within just weeks of the impact.
00:21:32But the consequences of the impact continue to plague the planet.
00:21:37When we talk about a mass extinction event,
00:21:39we also have to talk about what happened in the oceans and the seaways of the world.
00:21:4575% of the species that existed in the world's oceans were extinguished
00:21:49at exactly the same time the dinosaurs disappeared.
00:21:54Just as the effects of the impact obliterate the base of the food chain on land,
00:21:59they do the same in the oceans.
00:22:02Prolonged darkness kills plankton, an oceanic food staple.
00:22:08Some types of mollusks and primitive squid won't make it out alive.
00:22:14Acid rain could have initially fallen about a week after the impact event,
00:22:18but it may have occurred at an enhanced rate for periods up to 10 years.
00:22:23Even so, some of the impact-related pollutants cling to the atmosphere.
00:22:28After the impact dust settles,
00:22:30the Earth suffers from oppressive greenhouse temperatures and horrible droughts.
00:22:43Scientists who subscribe to the impact theory
00:22:45estimate it took over 100,000 years for the terrestrial ecosystem to recover
00:22:51and 3 million years for the oceans to return to normal.
00:22:58By that time, though, the dinosaurs were gone.
00:23:05This is not a simple story of extinction.
00:23:08That is, you cannot think of this as a gun and a bullet killing an organism.
00:23:14It wasn't that type of process.
00:23:17It was such a dramatic environmental assault on the Earth's surface
00:23:20that it was able to affect all of these ecosystems
00:23:24regardless of where they were on the Earth's surface.
00:23:27So if you ask the question,
00:23:29what caused this organism or this particular part of the Earth's surface to be extinguished,
00:23:35there isn't a single answer.
00:23:37And therefore, this is a process that affected not only the Tyrannosaurus rex
00:23:42or the duck-billed hadrosaurs that migrated across Colorado,
00:23:46but it affected plants and animals both on land and in the sea
00:23:50wherever they were around the world.
00:24:01What if a meteorite as big as the dinosaur killer hit today?
00:24:07It would leave a hole in the Earth big enough to stop it.
00:24:10It would leave a hole in the Earth big enough to smash everything from New York City to Philadelphia.
00:24:16And that would be just the beginning.
00:24:20When you have an asteroid hit, it throws up huge amounts of dust into the skies.
00:24:24Crops are going to fail, absolutely going to fail.
00:24:28Without crops, you've got a lot of starving humans.
00:24:33At minimum, several billion people would die.
00:24:36And we would be in for a struggle for mere existence.
00:24:43An asteroid impact should have left a wasteland of dead dinosaurs.
00:24:48But this is where the impact theory runs into a problem.
00:24:55If the theory is correct, then that layer, 66 million or a little less,
00:24:58should be full of dead dinosaurs.
00:25:00I mean full.
00:25:01They all died in a day or a week.
00:25:04We should have millions of dead dinosaurs in this impact zone.
00:25:09How many dead dinosaurs do we actually have worldwide in the impact zone, rounding off?
00:25:15None!
00:25:17Goose eggs, not a one.
00:25:19It's an elaborate crime scene theory where the victims are already dead.
00:25:24They're already dead!
00:25:26Could it be that something else killed the dinosaurs?
00:25:30If so, might this same something spell disaster for human civilization?
00:25:45A relentless onslaught of aftereffects caused by a mountain-sized fireball
00:25:50crashing into prehistoric Mexico 65 million years ago
00:25:55did end the dinosaurs.
00:25:57Or so goes the theory.
00:25:59Could it be wrong?
00:26:03The problem sometimes is that people who want to have a single impact theory
00:26:07don't know much about plants and animals,
00:26:09and they'll put out scenarios that, unfortunately,
00:26:12don't fit with what we have in the fossil record or what we know about modern biology.
00:26:18According to the single impact theory,
00:26:21the meteorite resulted in downpours of corrosive acid rain.
00:26:25That contributed to the mass extinction.
00:26:28If this is really what happened,
00:26:30animals living in or near the water should have been especially hard hit.
00:26:35And if that's the case, this creature shouldn't be alive.
00:26:40As you can see, because this animal is breathing, it's not plastic, it's a living tree frog.
00:26:45And its ancient relatives lived with the dinosaurs some 65 million years ago.
00:26:50Amphibians are extremely sensitive to environmental conditions,
00:26:54for example, acid rain,
00:26:56because they live and or breed in the water.
00:27:00So they're sort of like the canary in the coal mine.
00:27:03And what this indicates is that there could not have been very strong acid rain
00:27:07because that would have disrupted their life cycle completely.
00:27:13The survival of tree frogs isn't the only evidence.
00:27:17The survival of tree frogs isn't the only evidence that casts doubt on the single impact theory.
00:27:25Curiously, what lived and what died after impact doesn't fit a neat pattern.
00:27:35Sharks do very poorly.
00:27:37Most of those become extinct.
00:27:39Bony fishes, some survive, some don't.
00:27:43Crocodiles and alligators themselves survive.
00:27:48One of the groups that did the best in terms of survival are turtles.
00:27:52Something like 18 species of aquatic turtles survived the Cretaceous-Tertiary boundary.
00:27:57There's one land turtle that didn't survive, and that helped be living in the water,
00:28:02like this modern alligator snapper.
00:28:07It had ancient relatives, in fact, in the Cretaceous.
00:28:10So it obviously survived because it's here today.
00:28:14The survival of turtles also suggests the possibility
00:28:18that Earth never descended into the prolonged deep freeze
00:28:21described by supporters of the single impact theory.
00:28:25Cold-blooded animals, like turtles and lizards, can't generate their own body heat.
00:28:31And therefore, most would probably be doomed if subjected to an unusual cold spell.
00:28:38So whatever climate change existed at the end of the Cretaceous,
00:28:42wasn't big enough to freeze a turtle.
00:28:45If you can't freeze a turtle, you can't freeze a T. rex. You just can't.
00:28:53The climate may have changed, but maybe not as drastically as the impact theory proposes.
00:29:01If it gets real cold all of a sudden, I think there'll be some serious die-off,
00:29:04and I think there will be problems.
00:29:06But if it happens over a long-range period,
00:29:09I think a lot of animals that we know of today would adapt.
00:29:19Another pillar of the impact theory is that pervasive darkness starved the world's plant life,
00:29:25resulting in a massive food shortage for the largest animals.
00:29:29But insects need plants too, and they didn't have much trouble at all.
00:29:35There are a number of groups of insects, like the crickets and grasshoppers and beetles and things,
00:29:41that are really exposed to the outside.
00:29:44And if there was something that came and wiped out all the life on the face of the Earth,
00:29:49the insects certainly would have suffered.
00:29:53But they don't seem to have.
00:29:57At the end of the Cretaceous, all the insect families go right through.
00:30:01You know, why isn't this meteor, if it decimated all this life on the surface of the planet,
00:30:06how come all these insects are still around today?
00:30:15There's more evidence from the fossil record that the impact event may not have been as severe as first believed.
00:30:22Some dinosaurs survive to this day.
00:30:26What I'm holding in my hands is a living dinosaur.
00:30:29This animal is a white-bellied stork, very young,
00:30:32and he'll soon grow up to be, I guess, about a foot and a half tall, something like that.
00:30:39And when we say that he's really a dinosaur, what we mean is that dinosaurs, the group, gave rise to birds.
00:30:47I understand if someone looks at a Tyrannosaurus rex and then at a pigeon and wonders, how could this be possible?
00:30:56But you have to remember that there are millions of years of evolution separating these two species.
00:31:07We have plenty of evidence indicating that birds evolved from some small meat-eating dinosaur.
00:31:14That evidence comes from the shape of the bones, dinosaurs with feathers, and we have birds with teeth and long, bony tails.
00:31:24So we have been able to fill that gap, that huge anatomical gap.
00:31:33Any theory has to be able to explain why the birds survived and the other dinosaurs didn't.
00:31:41So it can't be a simple, simple answer that an asteroid hit and killed all the dinosaurs but left these guys intact.
00:31:53Maybe the effects of a meteorite impact on its own weren't as powerful as some think.
00:31:59Then is it just a coincidence that the dinosaurs vanished at roughly the moment the meteorite arrived?
00:32:06Some scientists believe that a different threat had already fatally weakened the dinosaurs.
00:32:12And inevitably, humanity will need to confront it as well.
00:32:18It seems only fitting that the disappearance of the ferocious dinosaurs would require a sudden catastrophic disaster.
00:32:26But such a scenario can't explain what scientists working along the picturesque Red Deer River Valley in the Badlands of Alberta, Canada, have uncovered.
00:32:57Dinosaurs were already vanishing for millions of years before the meteorite struck the planet.
00:33:05The Red Deer River is arguably one of the very best dinosaur sites anywhere in the world.
00:33:09We have almost 40 species of dinosaurs represented at this level in time, which is about 15 million years before dinosaurs disappear.
00:33:19So that's incredibly rich.
00:33:23Up the Red Deer River, you have younger rocks.
00:33:27And in those rocks, we see that there's only about 25 species of dinosaurs left.
00:33:32As we continue along the Red Deer River, we get into the terminal Cretaceous beds.
00:33:37We've only got about six species of dinosaurs left.
00:33:43Why was the Cretaceous world so hostile to dinosaur life?
00:33:48At the Royal Tyrrell Museum, situated in another section of Alberta's Badlands, Canadian scientists may have found a cause for the mysterious disappearances.
00:34:00You start having the climatic fluctuations.
00:34:03You have alternating periods of really warm temperatures and really cold temperatures.
00:34:09Generally, warmer temperatures support a wider variety of life forms.
00:34:14Warmer temperatures support a wider variety of lifestyles, and therefore a greater number of species.
00:34:21If you go into tropics where it's really warm, we have a tremendous number of different species.
00:34:27There's evidence that actually in periods when the world was warm, you have more species of dinosaurs.
00:34:34When you get to a colder climate, then usually the diversity of animals decreases.
00:34:39So that's probably what happened at the end of the Cretaceous.
00:34:44One of the patterns that we noticed right off the bat as we went through our rock record here through the last seven million years of the age of dinosaurs is that temperature sensitive animals, as fossils, just drop out.
00:35:00And then they come back into the rock record higher up.
00:35:05That swing from present to absent seemed to be happening more and more frequently as we went up through the rock record.
00:35:15It's easy to think that dinosaurs were evolutionary losers, obsolete creatures in a rapidly changing world.
00:35:23After all, you won't find a T-Rex at your local zoo.
00:35:27But that's not why they disappeared.
00:35:30Dinosaurs were always changing, always adapting, always evolving into new forms.
00:35:36We actually don't know of any dinosaur anywhere in the world that lasted more than, say, two or three million years.
00:35:44The arrival of new dinosaur species is what helped perpetuate one of the most successful and lengthy dynasties in our planet's history.
00:35:53Human civilization, by comparison, still barely warrants a footnote.
00:35:59For some perspective, if we express all of the years that span the entirety of the age of dinosaurs in a physical timeline stretching across North America, then the Pacific Coast represents the moment the first dinosaurs appeared on Earth some 220 million years ago.
00:36:20On the other coast, the Empire State Building in New York City marks present-day life in the 21st century.
00:36:28On this scale, every mile signifies about 50,000 years.
00:36:34The age of the dinosaurs continues from California until Chicago.
00:36:38It's not until we reach Newark, New Jersey, less than 20 miles from the Empire State Building, that humans appear on Earth.
00:36:46Written human history doesn't start until about half a block away.
00:36:51A human life on this scale takes up just a few feet.
00:36:55And yet, with all those years of evolutionary progress, suddenly the road ended.
00:37:06The bizarre thing at the end of the Cretaceous is all those dinosaur families disappear.
00:37:12All the horned dinosaur families, all the theropod dinosaur families, all disappear.
00:37:17In a cruel twist of fate, some dinosaurs may have been too well adapted to the wild climate fluctuations.
00:37:24For some species, their greatest strength led to their inevitable destruction.
00:37:31The greater bulk of the largest dinosaur species would have helped them tolerate wilder temperature extremes.
00:37:38The elephant, the largest land animal alive today, provides an example.
00:37:43They can be 12, 13 feet tall at the shoulder, weigh 6, 7, 8, 9 tons, so they get very, very big.
00:37:52When you have a larger body mass, if you're looking at short-term life expectancy,
00:37:58you're going to have a much larger body mass.
00:38:02When you have a larger body mass, if you're looking at short-term temperature changes
00:38:07between, say, day and night or between seasons, it doesn't affect you as much
00:38:11because your body temperature doesn't change as fast.
00:38:14They just basically were so massive that when they were warmed up by sun rays, they just stayed warm.
00:38:21This may be why we find large dinosaur species during the shifting climates of the late Cretaceous.
00:38:27Greater mass, however, also creates some important disadvantages.
00:38:33When you're really big, you essentially slow down your life.
00:38:38You mate less often, you have to have fewer children, and you have a longer life.
00:38:42But by having fewer children, essentially what happens, it means if there's a short-term change
00:38:48that's quite severe, then you're not able to adapt fast enough,
00:38:52either as a species or as an individual.
00:38:55And the chances of becoming extinct are much greater.
00:38:59Elephants require a 22-month gestation period and typically give birth to just one calf at a time.
00:39:06In contrast, rat pregnancies last only about 22 days,
00:39:12and one female rat could have as many as 15,000 descendants in just one year.
00:39:18Larger body mass also requires more food.
00:39:23It takes a lot of energy to keep them going.
00:39:26They have to have food, they have to have water.
00:39:29When you get big, you're usually to focus on food that will bring you a lot of nutrients.
00:39:35If you've got an elephant on very high-quality elephant food,
00:39:40it needs a lot of nutrients.
00:39:42If you've got an elephant on very high-quality elephant food,
00:39:47it needs 10 times, 15 times as much as its own body weight per 12 months.
00:39:54Now if the food is crummy, it's dry grass, it needs a lot more.
00:40:00Maintaining that weight forced the largest dinosaurs to evolve the optimal tools
00:40:05to get the most bang for their buck out of their available food sources.
00:40:12The hundreds of teeth lining the jaws of duck-billed dinosaurs
00:40:16cropped leaves from trees with woodchipper-like efficiency.
00:40:21It helped them grow to immense sizes,
00:40:24measuring up to 40 feet tall and weighing as much as three tons.
00:40:31These titanic-optimized eating machines with relatively small populations
00:40:37contained a critical flaw, though.
00:40:40What if there are no leaves? What if everything's been dropped
00:40:44because you've gone into essentially wintertime conditions worldwide?
00:40:49There's nothing for those animals to eat.
00:40:51They're not adapted to dig up roots and survive that way.
00:40:54Other animals that were smaller possibly could have done that.
00:40:57If climate change was driving their communities towards large size,
00:41:02it's almost as though dinosaurs were being set up for failure.
00:41:06Once the big herbivores starved and died,
00:41:09and all the meat disappeared for the big carnivores,
00:41:12they couldn't, of course, go and hunt smaller animals
00:41:15because they were too big to actually catch them, too slow.
00:41:20So they would die.
00:41:24They're the ones that are least well-adapted for rapid change.
00:41:30Unfortunately for the dinosaurs,
00:41:32this is exactly what happened when the fist of fate,
00:41:35in the form of a mammoth meteorite,
00:41:38delivered a body blow to the planet.
00:41:47The threat of climate change and its potential cataclysmic effects
00:41:52looms over humanity.
00:41:54Rising oceans, mighty hurricanes,
00:41:58and extreme drought among them.
00:42:01But one model for dinosaur extinction suggests
00:42:05that its effects are more systemic.
00:42:09I don't feel that if the asteroid had hit earlier,
00:42:12when they had better diversity,
00:42:15that dinosaurs would have necessarily gone extinct.
00:42:18In this extinction scenario,
00:42:20the meteorite delivers a knockout blow,
00:42:23not to a mighty dinosaur empire,
00:42:26but rather to a crumbling dynasty.
00:42:29And that's a warning for us,
00:42:31because we're looking at a time now
00:42:33where we're losing a lot of our biodiversity.
00:42:36And the question is, is this setting us up
00:42:39for something really catastrophic to happen?
00:42:42Maybe dinosaurs have a clue on that one.
00:42:47It may be too late.
00:42:49Some scientists believe our world today
00:42:52is already undergoing a mass extinction.
00:42:54Over half of all reptile and insect species are in danger,
00:42:59as well as three quarters of all flowering plants.
00:43:04Amphibians, like frogs and salamanders,
00:43:07have survived on this planet for over 300 million years,
00:43:11even outlasting dinosaurs.
00:43:15Within the last quarter century, however,
00:43:18hundreds of their kind have gone extinct.
00:43:20Global climate change has the potential
00:43:24to be the straw that broke the camel's back
00:43:28for a great many species on Earth.
00:43:31A large number of species are living in isolated little habitats
00:43:36that remain as we've taken over large parts of the rest of the Earth.
00:43:40If these habitats are under climate stress,
00:43:43there's no place for the animals to go.
00:43:45When the habitats shrink enough, however,
00:43:48you have very little resilience.
00:43:51And that's what worries me.
00:43:55As species disappear,
00:43:58we may be following dinosaurs down a dead-end road.
00:44:03However, there may be nothing we as humans can do
00:44:07about a future greenhouse or ice house world.
00:44:10A random natural cycle may play a part.
00:44:15We know that where I'm sitting right now
00:44:18was under a half a mile of ice 10,000 years ago.
00:44:22We also know that roughly 10,000 years from now,
00:44:26this area will again be under a half a mile of ice.
00:44:30We're in between two glaciations.
00:44:33These may be the result of a slight change in climate.
00:44:37These may be the result of a slight wobble
00:44:40in the Earth's rotation as it orbits the sun.
00:44:45And by looking at the accumulation of the wobbling of the Earth,
00:44:49it does seem to correlate with the known ice age cycles.
00:44:55In some sense, the rise of human civilization was an accident
00:45:00caused by the melting of the ice 10,000 years ago.
00:45:04And we have another good 10,000 years
00:45:07before we either leave the Earth or go underground.
00:45:13This may have contributed to the loss of dinosaur species.
00:45:20However, this scenario still relies
00:45:23on a meteorite screaming in from the heavens.
00:45:27But some scientists believe that the meteorite
00:45:30might just be a red herring.
00:45:34We have no evidence that any single dinosaur or dinosaur species,
00:45:39except birds, lived long enough to be whacked by the meteorite.
00:45:42None.
00:45:45This you should find deeply disturbing.
00:45:49In other words, dinosaurs may have already been extinct
00:45:54by the time the meteorite struck.
00:45:57If the dinosaur world ended in a bang,
00:46:00then where are all of the carcasses?
00:46:04Supporters of the impact theory argue
00:46:07that much of the evidence has been lost to the sands of time.
00:46:13It's very naive to say what was a catastrophic event.
00:46:18We should find all the dead carcasses lying one next to the other.
00:46:27There may have been a dinosaur
00:46:30wandering over there a mile downstream.
00:46:33There may have been a herd of dinosaurs
00:46:36two or three miles upstream.
00:46:38But right here, where we're standing,
00:46:41where the rock record is preserved,
00:46:43there might not be a dinosaur body.
00:46:45When we look at impact debris
00:46:49that can clearly be linked to an extraterrestrial body,
00:46:53we don't expect to see that debris covering a dinosaur bone bed.
00:47:00But could the lack of bones mean something else?
00:47:04Ten billion dinosaurs died at 65.8 million years,
00:47:09but for some reason, none of them were preserved.
00:47:11None of them. Do you buy this?
00:47:13Do you buy that?
00:47:15That's like the St. Valentine's Day massacre.
00:47:19If all the bodies were there
00:47:21the day before the guys with the submachine gun showed up,
00:47:24wouldn't there be a problem in the timeline?
00:47:27The guys are already dead.
00:47:28You know, they're already dead.
00:47:34If the dinosaurs were already dead before impact,
00:47:38what killed them off?
00:47:41A different theory blames a menace
00:47:44that dinosaurs couldn't even see.
00:47:52Scientists are sounding the alarm
00:47:54that the world may be undergoing a dangerous transformation.
00:47:58They warn that if the world is indeed growing hotter,
00:48:02one consequence may be that ocean levels could rise and drown coastlines.
00:48:08The opposite effect might also be catastrophic.
00:48:12The dinosaur world suffered from a collapse of sea levels,
00:48:16and the effects may have led to the mass extinction.
00:48:20During the age of dinosaurs,
00:48:22ocean levels were much higher than they are today.
00:48:26In North America, for example,
00:48:29everything from the Rocky Mountains
00:48:31to what is today the Mississippi River lay underwater.
00:48:35Then, mysteriously, sea levels declined and disrupted the environment.
00:48:41You start getting a land mass being built,
00:48:44and under those circumstances what happens
00:48:47is that you get a more continental climate.
00:48:49As the sea withdrew,
00:48:52you started getting colder winters, hotter summers,
00:48:56cooler nights, and warmer days.
00:49:00Falling sea levels also exposed new terrain.
00:49:04This created land bridges that connected continents once separated by water
00:49:09and opened the way for a dinosaur killer
00:49:12that may have ravaged life on Earth many times before.
00:49:20The first time it struck may have been 250 million years ago,
00:49:25during an age known as the Permian.
00:49:29Fossilized remains from that era can be found near the town of Seymour
00:49:34in the wide-open spaces of north-central Texas.
00:49:38Most things that lived during that time died.
00:49:41It's the worst mass extinction that's ever existed on the face of the Earth.
00:49:45The mass death of the Permian carries special significance.
00:49:49Because it was the first extinction for life on land.
00:49:56This is up to 200 million and change earlier than T. rex,
00:50:02earlier than the great dinosaur extinction.
00:50:04It's like following a serial killer.
00:50:07You gotta look at the first one and then go up in time.
00:50:11Gotta look at the first one.
00:50:13Scientists working here believe they've found a link
00:50:15between this extinction and the one at the end of the Cretaceous
00:50:20that wiped out the dinosaurs.
00:50:22If you want to know what killed the dinosaurs,
00:50:25gotta look at the very first extinction.
00:50:27And that brings you right here.
00:50:29Dr. Bakker and his team claim that a global pandemic of sickness and disease
00:50:35may have ravaged the Permian world.
00:50:38And when they looked at the factors they believe led to the outbreak of the Permian,
00:50:42they discovered similar ones at the end of the Cretaceous.
00:50:46A pattern emerged.
00:50:54However, according to this sickness and disease extinction scenario,
00:50:59the climate changes involved with dropping sea levels
00:51:02were not what overwhelmed the dinosaurs.
00:51:05You see, the problem with the climate model for any mass extinction,
00:51:09if you change the climate from hot to cold,
00:51:14or dry to wet,
00:51:16you might hurt some big dinosaurs, some big mammals.
00:51:20The other half love it.
00:51:22There's not one simple worldwide climate change you could produce
00:51:27to kill all elephants and rhinos and hippos and giraffes and water buffalo.
00:51:31Can't do it. Can't do it.
00:51:33As water levels fell,
00:51:35separate continents became linked
00:51:38and eliminated borders between creatures.
00:51:43If a bunch of big species from Asia
00:51:46invades North America and gets down to Texas,
00:51:49all epidemiological hell breaks loose.
00:51:52Each foreign species can be a pest,
00:51:55and they bring their fleas, ticks and tapeworms and nematodes.
00:51:59They bring all kinds of diseases.
00:52:00They bring tapeworms and nematodes.
00:52:02They bring a host of pests with them.
00:52:11The globe looks different today than it did during the Permian.
00:52:15The outer crust of our planet consists of plates
00:52:18that float over the layers of rock underneath.
00:52:21Each of these plates moves in different directions at different speeds.
00:52:26The continents of the Permian era were all stuck together,
00:52:30forming the giant landmass of Pangaea.
00:52:34You could walk from here, Seymour, Texas, to Morocco.
00:52:38You could walk from Massachusetts to India.
00:52:42You could walk from Alabama to Australia
00:52:46without ever crossing an ocean.
00:52:49We can find some of the same species
00:52:52We can find some of the same geographic danger signs
00:52:55in the age of dinosaurs.
00:52:57Newly formed land bridges incited a dangerous wave of dino immigration.
00:53:04Suddenly, we have a connection,
00:53:06a continental connection between North America and South America.
00:53:09The duck-billed dinosaurs that are common here in Alberta
00:53:12are suddenly appearing down in Argentina.
00:53:15The sauropod dinosaurs, which had already become extinct in North America,
00:53:18suddenly appear again in North America in Texas and Utah and places like that.
00:53:24Those big sauropods are, in fact, migrants coming from South America
00:53:29using the same land bridge that allowed the hadrosaurs to go south.
00:53:34Because the largest animals were capable of traveling the farthest,
00:53:38they put themselves at greatest risk.
00:53:42Big animals have a natural ability to spread.
00:53:45Elephants, as soon as new species of elephants evolved in the age of mammals,
00:53:50they'd spread from Africa to Europe, Europe to India,
00:53:53and some made it from India to Siberia to North America
00:53:56and all the way down to Terra del Fuego.
00:53:58Very impressive.
00:54:00Being big confers that power of tourism.
00:54:07Once they're on the move, organisms can cause problems
00:54:11simply by disturbing the natural cycle of life.
00:54:13Simply by disturbing the natural cycle of the environment they're invading.
00:54:21The invading species is a danger for a bunch of reasons.
00:54:26It could kill you to be a new predator.
00:54:31It could rob you of food.
00:54:33It could rob you of places to make a nest of your young.
00:54:38It could chase your young.
00:54:40It could squash your young.
00:54:41And those are the least dangerous things.
00:54:45Infinitely more destructive are the illnesses delivered and picked up by nature's migrants.
00:54:51An animal's natural defenses, developed over generations for a certain environment,
00:54:57may turn out to be completely useless in another.
00:55:02Moose and deer make each other sick.
00:55:05African elephants and Indian elephants make each other sick
00:55:08because their immune systems have evolved to handle different pests.
00:55:13The mixing of species can cause every meal to become potentially lethal.
00:55:19But every time you eat leaves, grass, branches, fruit,
00:55:24you can get some unwanted microbes who can run amuck in your gut,
00:55:28causing you, well, for instance, diarrhea.
00:55:32Diarrhea can dehydrate an adult male in a week and kill an infant in a day.
00:55:40Diarrhea is the symptom that kills more humans than any other symptom.
00:55:45It can be caused by many things.
00:55:47But alas, people die of diarrhea all the time.
00:55:51Diarrhea ain't no joke.
00:55:53The nefarious range of afflictions affecting the largest dinosaurs of the late Cretaceous
00:55:58reached debilitating levels.
00:56:01Some of nature's smallest creatures only made things worse.
00:56:07As if teleported to the present by a time machine,
00:56:11these very insects preserved perfectly in place.
00:56:16But they're not the only creatures to suffer.
00:56:20These very insects, preserved perfectly in fossilized amber,
00:56:25once walked, flew, and even fed on dinosaurs.
00:56:33Dr. George Poinar believes that the pathogens insects carried
00:56:38assaulted dinosaurs relentlessly from all angles
00:56:41and ultimately played a serious role in their demise.
00:56:45And these are three nematodes that came from a capsule
00:56:49in the body cavity of a cockroach.
00:56:53Cockroaches will eat the eggs of these,
00:56:57and then if a dinosaur came along and ate the cockroach,
00:57:01it would get infected.
00:57:06They look harmless, but once inside the body,
00:57:10these worms grew into dinosaur assassins.
00:57:15This is usually the typical way in which these things are found.
00:57:22Here's one, for instance, here.
00:57:26Being stricken by stomach worm is gruesome and torturous.
00:57:31The nematode eggs start in the stomach,
00:57:35but work their way into the lung tissue.
00:57:38This induces a coughing fit.
00:57:41The eggs, ejected from the lungs,
00:57:44return to the stomach, where they hatch and grow into worms.
00:57:49As they grow larger and fill the stomach,
00:57:52the duckbill loses its appetite and weakens.
00:57:55The worms can even cause organs to rupture.
00:57:59The largest nematode today is about 27 feet,
00:58:03so it's possible for these nematodes to reach large sizes
00:58:07under the right conditions.
00:58:11DINOSAURS
00:58:17Exotic biting insects also targeted dinosaurs mercilessly.
00:58:22They came for blood and often left behind deadly illnesses.
00:58:27The sandfly reigned as one of the most successful dinosaur hunters of its day,
00:58:33in part because it developed the perfect utensils for dino-dining.
00:58:38And if you look very carefully at the mandibles of the sandfly,
00:58:43you see that they resemble the edges of common steak knives today.
00:58:50As sandflies arrive to torment this triceratops,
00:58:54they put their steak knife mandibles to good use.
00:59:00So what we have are a pair of mandibles,
00:59:03and first one is inserted a little bit into the flesh,
00:59:05and then the other one is inserted into the flesh.
00:59:08You have these blades going back and forth very quickly,
00:59:11and they simply cut through the flesh.
00:59:14It's really a marvel of invention.
00:59:19Targeting the most sensitive areas,
00:59:22the sandflies swarm the soft tissues around the eyes, nose and mouth.
00:59:28According to Poinar,
00:59:30dinosaurs may not have been able to defend themselves
00:59:32against the fleets of flying insects.
00:59:37I think the dinosaurs would have essentially been sitting ducks to these insects.
00:59:42What did the dinosaurs really have in order to get rid of these?
00:59:46To shoo the flies, supposedly.
00:59:49I mean, they didn't have long tails like horses.
00:59:52You often see horses standing back to head,
00:59:54where the tail of one brushes the flies from the head of the other one.
00:59:58As sandflies gorge on blood,
01:00:01they inject a dangerous illness called leishmania.
01:00:07It's a disease that exists to this day.
01:00:10Modern sandfly cousins are carriers.
01:00:15It travels the blood attacking organs,
01:00:18and causes internal bleeding and death.
01:00:22This adult triceratops is infectious.
01:00:25This adult triceratops is sick.
01:00:28But she is just one of many in a herd
01:00:31suffering from a virulent strain of leishmania.
01:00:35Blotches and sores mean she's in a badly weakened state.
01:00:42Dinosaur species were very closely related to each other.
01:00:46Therefore, once a killer disease got hold of one species,
01:00:49it may have spread to others with frightening ease.
01:00:52Trailing t-rexes see an opportunity.
01:00:56Their hunger will soon be satiated.
01:01:00Mealtime for the predators begins.
01:01:04As they eat, the virus coursing through the sickened triceratops
01:01:08infects the scavengers.
01:01:11This will be their last supper.
01:01:14Ultimately, the sandfly terrorists will decimate
01:01:17the rest of the triceratops herd.
01:01:20This one insect, and one disease,
01:01:23could have wiped out thousands of dinosaurs.
01:01:27But it would take more than that to tackle the entire species.
01:01:32Multiple diseases, multiple pests,
01:01:35multiple invasive species, 10, 20, 30, 40.
01:01:38They could penetrate every habitat and wreak havoc.
01:01:41It was a combination of diseases,
01:01:44and it was a combination of diseases
01:01:46that spread throughout the dinosaur population.
01:01:55This is what I'd like to do. I think this is very important.
01:01:58Call a time-out to all thinking and publishing by paleontologists
01:02:01about extinction for five years.
01:02:04And every one of us should be forced to intern at the Bronx Zoo,
01:02:07San Diego Wild Animal Park,
01:02:10and Wyoming Fish and Game.
01:02:12And learn what guys who worry about extinction of living animals
01:02:15are concerned about.
01:02:18And it's not a meteorite.
01:02:21Disease, pests, competition
01:02:24between African and Indian critters,
01:02:27that's number one.
01:02:32The power of disease to shape world history
01:02:35can be found even in comparisons.
01:02:38It's not just a matter of how many species
01:02:40there are in the world.
01:02:43The power of disease to shape world history
01:02:46can be found even in comparatively recent times.
01:02:49Nothing has killed more people.
01:02:52Not natural disasters, not famine,
01:02:55and not even wars.
01:02:58The possibility of a great plague,
01:03:01of course, resonates with human history
01:03:04because we've had plagues in the past.
01:03:07In some cases, they wiped out
01:03:10so there was a disease that came in
01:03:13that killed all the potatoes.
01:03:16People began starving and then you had a number of diseases
01:03:19that came in and wiped out a large number of the population.
01:03:22People observing this from the healthful safety
01:03:25of modern civilization forget the power of deadly microbes.
01:03:28They're living happily and nothing has happened to them.
01:03:31If they go down into the tropics
01:03:34like in Africa or Asia today
01:03:37and look around and see
01:03:40the things that are occurring,
01:03:43suddenly they get a different view.
01:03:46Disease takes on a different aspect.
01:03:49Disease then becomes a controlling factor.
01:03:52Not something that we control, but something that controls us.
01:03:55Technology provides the land bridges of our time
01:03:58and teamed with environmental changes
01:04:01could expose humanity to new diseases.
01:04:04We may be on the precipice of a new global plague.
01:04:08If disease extinguished the dinosaurs,
01:04:11could it do the same to human beings?
01:04:15Plague has the possibility
01:04:18that an asteroidal impact doesn't have
01:04:21and that is of wiping out absolutely everybody,
01:04:24but it's very unlikely.
01:04:27For one thing, pockets down in nuclear submarines
01:04:30at the bottom of the sea can simply wait the plague out
01:04:33until all previous victims are already dead.
01:04:36The scientific community, however,
01:04:39hasn't embraced the idea of a Cretaceous-era
01:04:42dinosaur-killing pandemic.
01:04:46To see the entire group being annihilated by disease
01:04:50is a little hard to swallow.
01:04:53With a global cosmopolitan distribution of dinosaurs
01:04:56in different dinosaur groups,
01:04:59nothing that we know of on this planet
01:05:02works homogeneously.
01:05:05It spreads homogeneously over the whole surface of the planet.
01:05:10And how do you explain that those diseases
01:05:13killed seagoing animals like marine reptiles,
01:05:16ammonites, animals that are so distantly related
01:05:19that they probably wouldn't have been affected
01:05:22by diseases that grew on land?
01:05:25The answer may lie in another Cretaceous-era apocalyptic force,
01:05:29one that vomits the fires of hell
01:05:32all over a helpless dinosaur world.
01:05:35CRETACEOUS
01:05:45These jagged, steppe-like mountains of central India,
01:05:49known as the Deccan Traps,
01:05:52contain the leftovers of another dinosaur-era disaster,
01:05:55one perhaps many times more ruinous
01:05:58than the meteorite impact or disappearing seas.
01:06:01According to Goethe Keller,
01:06:04a mass extinctions expert from Princeton University,
01:06:07the key to the extinction of the dinosaurs can be found there.
01:06:11Although calm and peaceful today,
01:06:1465 million years ago,
01:06:17India was the epicenter of destruction.
01:06:22A massive outpouring of volcanic lava
01:06:25formed this entire range.
01:06:27It covers 200,000 square miles,
01:06:30an area about the size of Texas,
01:06:33and its tallest peaks reach over a mile high.
01:06:38It started when plumes of molten magma
01:06:41from deep within the Earth burst through the surface.
01:06:45High columns of fires
01:06:48blasted gas and ash into the stratosphere,
01:06:51and on the bottom you had these lava sheets
01:06:54flowing out and covering the entire area.
01:06:57Miles and miles,
01:07:00hundreds, thousands of miles.
01:07:04These volcanic eruptions called flood basalts
01:07:07are not equivalent to Mount St. Helens
01:07:10or some volcano that we see in the news.
01:07:13These are great fissures in the Earth.
01:07:16The crust of the Earth splits apart. Lava pours out.
01:07:20As destructive as the lava flows were,
01:07:23it was the noxious gases belching out
01:07:25that brought the ultimate extermination.
01:07:28Human history provides a harrowing example.
01:07:33On June 8, 1783,
01:07:36near the town of Laki in Iceland,
01:07:39a volcano erupted.
01:07:43It lasted for eight months,
01:07:47with brutal consequences.
01:07:50The sun turned blood red,
01:07:52and a very thick haze covered
01:07:55essentially not just Iceland,
01:07:58but spread over Europe.
01:08:01It instantly killed 50% of the livestock.
01:08:04After that,
01:08:07poison rain fell from the sky.
01:08:10Thick with ash, sulfur, and salt,
01:08:13it coated all the plants,
01:08:16which turned bright yellow and withered and died.
01:08:19It caused enormous famine
01:08:22and about 25% of the population died.
01:08:30The haze disrupted worldwide weather patterns.
01:08:34That summer,
01:08:37Europe endured unprecedented high temperatures,
01:08:40and the following winter brought record cold
01:08:43to as far away as North America.
01:08:53As destructive as Laki was,
01:08:56it was nothing but a squirt gun
01:08:59compared to the cannon fire of the Deccan eruptions.
01:09:02They were up to 5,000 times larger
01:09:05and would seem to be a leading dinosaur-killing suspect.
01:09:12But many scientists don't believe
01:09:15that the Deccan eruptions caused the mass extinction.
01:09:18Why?
01:09:20It's the same reason a similar series of eruptions
01:09:23about 17 million years ago
01:09:26from the Columbia Plateau in America's Pacific Northwest
01:09:29didn't cause a mass extinction of its own.
01:09:32All these are volcanic rocks,
01:09:35essentially from one single eruption
01:09:38in the Columbia Plateau basalts.
01:09:41And so they represent
01:09:44one of these pulsed eruptions.
01:09:47And it would have deposited
01:09:50within days or weeks.
01:09:53When you go further down this mountain,
01:09:56you will find a plateau,
01:09:59which appears to be the break
01:10:02between this eruption and the next.
01:10:05Each successive pulse created another layer
01:10:08and added a step to the Columbia formation.
01:10:13And even though the volcanic lava
01:10:16spread out over tens of thousands of square miles,
01:10:18it didn't have the earth-shattering effect
01:10:21you might expect.
01:10:24The reason is that all of the Columbia Plateau pulses
01:10:27took more than 10 million years to form.
01:10:31The long intervals between each eruption
01:10:34allowed the surrounding environment to recover.
01:10:38If you just have one pulse
01:10:41that lasts for 10 years,
01:10:44it could be washed out within
01:10:4610 to 100 years afterwards.
01:10:52But if the next eruption went off
01:10:55before the environment fully recuperated,
01:10:58living conditions would have worsened exponentially.
01:11:03The conventional wisdom held
01:11:06that the Deccan Traps were blunted
01:11:09because they erupted over a million-year time frame.
01:11:12In the last few years,
01:11:14all this has changed.
01:11:17The eruptions now are known
01:11:20to occur over very short time,
01:11:23like 10,000 to 100,000 years.
01:11:26New dating techniques have revealed
01:11:29that the bulk, up to 80% of the Deccan eruptions,
01:11:32began near the end of the Cretaceous
01:11:35and finished at the time of the mass extinction.
01:11:38In effect, the pulsed explosions
01:11:41of the Deccan volcanoes
01:11:44are deadly blows to the world's ecosystems.
01:11:47Just one major eruption pulse
01:11:50could have injected as much poison gas
01:11:53into the atmosphere as the Yucatan impact.
01:12:02Both are catastrophes that would have caused
01:12:05earthquakes, tsunamis,
01:12:08fires, although not global fires,
01:12:11but certainly regional fires,
01:12:14poisoning, poisonous clouds of gas,
01:12:17and cooling.
01:12:21However, all the pulses taken together
01:12:24would have had the effect of dozens of meteorite impacts
01:12:27spread out over thousands of years.
01:12:31The effects of India's volcanoes engulfed the planet.
01:12:35Keller believes the Deccan volcanoes
01:12:38unleashed poisonous gas clouds
01:12:41that blocked sunlight.
01:12:44Animals in the neighborhood would have struggled to breathe,
01:12:47and rain would have absorbed the airborne gases,
01:12:50wrecking vegetation worldwide as it fell.
01:12:54Basically, we can say we found the smoking gun.
01:12:57The Deccan volcanoes,
01:13:00which are the largest in the world,
01:13:02are the main contenders for the smoking gun.
01:13:05The Deccan volcanism theory
01:13:08becomes the main contender for the mass extinction.
01:13:11Supervolcanism may even lead
01:13:14to a mass extinction of humans.
01:13:17One of America's most popular tourist destinations
01:13:20happens to sit on top
01:13:23of one of these ticking time bombs.
01:13:32A meteorite impact.
01:13:35Climate change.
01:13:38Falling sea levels.
01:13:41Disease.
01:13:44Volcanoes.
01:13:47What killed the dinosaurs?
01:13:50And which scenario most threatens human civilization?
01:13:54There's a difference between the kind of catastrophe
01:13:57that could knock us down,
01:13:59which means 99%,
01:14:02and actually extinguishing humans.
01:14:05Those are two different things.
01:14:08You can wipe out 99% of the cockroaches in your house,
01:14:11and there's still going to be a breeding pair somewhere.
01:14:16It's tempting to think that whatever knocked out the dinosaurs
01:14:19could never be a problem today.
01:14:22But what's bubbling beneath Yellowstone National Park
01:14:25right now proves otherwise.
01:14:27The park sits on a vast reservoir of magma,
01:14:30essentially a giant volcano.
01:14:33Scientists believe it erupts every 600,000 years,
01:14:36and the last eruption
01:14:39was 640,000 years ago.
01:14:42We're overdue.
01:14:52A gigantic supervolcano explosion of Yellowstone
01:14:54could have the same effects
01:14:57as an asteroid impact,
01:15:00in which case billions would die,
01:15:03and the survivors would struggle.
01:15:07Humans might soon be forced to face an environment
01:15:10like the one that may have assaulted the dinosaurs
01:15:13during the Deccan eruptions.
01:15:18On the other hand,
01:15:21the dinosaurs could have been the victims
01:15:24of an ancient exterminator,
01:15:27one that keeps coming back
01:15:30and might strike us next.
01:15:33Every 26 million years or so,
01:15:36we're not quite sure,
01:15:39there seems to be a massive extinction.
01:15:42And so the question is,
01:15:45what in the world could come back every 26 million years?
01:15:48A suspect looms at the distant fringes of our solar system.
01:15:51A horde of comets,
01:15:54giant orbiting ice cubes known as the Oort Cloud,
01:15:57could be responsible for mass death.
01:16:05As our solar system travels through the Milky Way,
01:16:08it dips into and out of the dense,
01:16:11dust-filled central band of our galaxy
01:16:14roughly every 26 million years.
01:16:17It'll encounter the dust,
01:16:20and that'll jiggle the Oort Cloud.
01:16:22These stationary ice cubes in space
01:16:25will then be jostled and will come raining down
01:16:28toward the sun,
01:16:31creating a comet storm
01:16:34that could perhaps wipe out the planet Earth.
01:16:37So the motion of the solar system in the galaxy,
01:16:41like a hobby horse in a merry-go-round,
01:16:44could in fact have wiped out the dinosaurs.
01:16:47If so, that means we're due for another big one,
01:16:50and perhaps another 13 million years.
01:16:55The solar system is like a shooting gallery.
01:16:58Look at the moon. Every night it comes out,
01:17:01and you can see pockmarks from heavy bombardment
01:17:04that took place on the moon.
01:17:06If you take a look at Mars, you see also evidence
01:17:09of enormous, gigantic comets that rain down on the Red Planet.
01:17:16So we have ample evidence that in the past,
01:17:18the solar system was a shooting gallery.
01:17:25An aerial bombardment crushing our civilization
01:17:28might still be millions of years away.
01:17:35But another potential dinosaur killer,
01:17:38also born in the depths of space,
01:17:41may not give us any warning.
01:17:43Well, human extinction could be brought about
01:17:45by nasty things from space.
01:17:48Whenever a massive star larger than our sun runs out of fuel,
01:17:53it collapses under its own weight and erupts into a supernova.
01:17:57If a star explodes within 25 light-years of the planet Earth,
01:18:02it could very well turn life on the surface of the Earth
01:18:06into a hell.
01:18:09If we have this blast of energy coming from a supernova,
01:18:12first of all, it will hit the atmosphere of the Earth
01:18:15and perhaps blow off and destabilize our ozone layer.
01:18:19Without an ozone layer to protect the Earth
01:18:22from harmful ultraviolet radiation,
01:18:24X-ray radiation from the sun,
01:18:26we would be bathed in dangerous radiation.
01:18:32We might have to live underground
01:18:34and develop crops that can withstand
01:18:36the lack of an ozone layer.
01:18:39It would be one of those intermediate events
01:18:42where billions might die,
01:18:44and some would keep going.
01:18:52Might an exploding star have vanquished the dinosaurs?
01:18:57A wave of radiation has been found
01:19:00that would have to actually pass through this planet
01:19:03about 65 million years ago,
01:19:05which makes it a little suspect that a star did go supernova
01:19:08at the right time to affect the Earth.
01:19:13The repercussions would have been wicked.
01:19:17We're talking about an object that flares up,
01:19:19visible in daytime and at night.
01:19:22It would outshine even the moon.
01:19:24It would be perhaps the brightest object in the night sky.
01:19:30We would have this rain of harsh radiation
01:19:33coming down on the Earth,
01:19:35wiping out any animals that are exposed to sunlight,
01:19:38exposed to the atmosphere of the planet Earth.
01:19:40Any animals with eyes would be blinded,
01:19:43not to mention horrible sunburns.
01:19:47There's no doubt that radiation, of course,
01:19:50causes changes to our genome
01:19:53that can cause, of course, cancers and things like that.
01:19:58Plants would die.
01:20:00Vegetation would wither on the vine
01:20:02with this enormous withering blast of radiation
01:20:05from outer space.
01:20:07And then animals that eat,
01:20:08vegetables and vegetation would also begin to die,
01:20:11and then meat eaters would also die as a consequence.
01:20:21Science, however, isn't persuaded
01:20:23by the suggestion of a dinosaur-killing supernova.
01:20:27There just aren't enough bones
01:20:29sitting on the Cretaceous-Tertiary boundary
01:20:31to say that, okay, the dinosaurs may have been affected
01:20:33more by a massive dose of radiation than other animals.
01:20:36We just don't see it in the fossils themselves.
01:20:41This is why the answer for what killed the dinosaurs
01:20:44has eluded us for so long.
01:20:48We don't really have a perfect book
01:20:52with every page of the fossil record.
01:20:56There are many, many pages that are missing.
01:20:59What we do not know very well
01:21:02is what happened exactly at the Cretaceous-Tertiary boundary.
01:21:06And that's the kind of evidence
01:21:08that we need to answer the question
01:21:11of what happened to the large dinosaurs,
01:21:13because it's then when they became extinct.
01:21:17Only by bringing all of the theories together
01:21:20may we finally have an answer
01:21:22for the disappearance of the dinosaurs
01:21:24and a verdict for what may doom humanity.
01:21:33Ever since we discovered the first dinosaur,
01:21:36the first evidence of dinosaurs,
01:21:38we've been entranced with their lives.
01:21:42They're fun.
01:21:44They illuminate your brain
01:21:46with all these shapes and sizes and colors
01:21:49and different periods, Triassic, Jurassic, Cretaceous.
01:21:51It overwhelms you. It's really cool.
01:21:54It's the prehistoric zoo.
01:21:59But it's their deaths we need to understand.
01:22:03It may be that we can learn some lessons
01:22:06from a mass extinction
01:22:08that was closest to today than anything before.
01:22:14With the potential fate of humanity hanging in the balance,
01:22:18we can't afford to get it wrong.
01:22:21These were horrendous creatures
01:22:23that suddenly vanished off the face of the Earth.
01:22:26It's almost as though dinosaurs were being set up for failure.
01:22:29Earthquakes, tsunamis, poisonous clouds.
01:22:32Wintertime conditions worldwide.
01:22:33It's an elaborate crime scene theory
01:22:36where the victims are already dead.
01:22:38They're already dead!
01:22:40Trillions upon trillions of meteors.
01:22:43The big poisonous gas clouds.
01:22:45Hitting the atmosphere all at the same time.
01:22:48The Earth cracked open.
01:22:50Yet all epidemiological hell breaks loose.
01:22:52Through the Earth's atmosphere,
01:22:54portions of the Earth are crumbling.
01:22:56Following a serial killer.
01:22:58Exploding.
01:23:00That always spells disaster.
01:23:03The truth has been elusive.
01:23:07People like a single answer.
01:23:09They like a single cause.
01:23:11It's how our minds work.
01:23:13And it's certainly how science works to a degree
01:23:15to find the single cause.
01:23:17If you're trying the asteroid for murder one,
01:23:19for killing the dinosaurs, murdering the dinosaurs,
01:23:21would you have enough evidence to convict?
01:23:23In reality, probably not.
01:23:25But it's going to be some sort of mixture
01:23:27of a lot of different factors that come together
01:23:29that created the events that led to the extinction
01:23:31of these animals.
01:23:33It's a confluence of events.
01:23:35Things all coming together at one time
01:23:37where, wow, if they came separately,
01:23:39you could deal with them.
01:23:41But when they come all together, it's just too much.
01:23:43Maybe this is the true answer to the mystery.
01:23:46A perfect concert of mega disasters
01:23:49inundated the world of the dinosaurs
01:23:51and brought it to its knees.
01:23:54Deccan volcanoes were mauling the Earth's environment
01:23:57for many millennia.
01:23:59These eruptive pulses, aided by declining seas,
01:24:02may have helped induce the wild fluctuations
01:24:05of the Earth's climate
01:24:07from greenhouse to ice house and back.
01:24:11This caused the diversity of dinosaur species
01:24:14to fall to a precarious few.
01:24:16Meanwhile, the falling seas opened land bridges
01:24:20and helped let loose a horde of pathogens.
01:24:23Then came the last straw, a massive meteor.
01:24:27When dinosaurs were really at their lowest point
01:24:31in biodiversity is when the asteroid hit.
01:24:34So it was a very, very bad day for them.
01:24:37An asteroid can cause extinction
01:24:40if it hits an ecosystem
01:24:42that's already hit hard by something else.
01:24:45So the meteorite,
01:24:47the meteorite that hit the Earth
01:24:50is a meteorite that's already hit hard
01:24:53by something else.
01:24:54So the meteorite,
01:24:56thought to be the arch-villain
01:24:58in the dinosaur extinction drama,
01:25:00may really have played only a supporting role.
01:25:03It might have just been adding insult
01:25:06to an already fatal injury.
01:25:09All I can conclude is that
01:25:12we have vastly overestimated
01:25:14the catastrophic effects of an impact.
01:25:18I believe that dinosaurs were doomed
01:25:20whether or not there was an asteroid
01:25:22hitting the Earth.
01:25:27Either way,
01:25:29this is not a simple tale of impact
01:25:32followed by extinction.
01:25:34A complex interaction of events
01:25:36combined to fulfill a fate
01:25:38many thousands of years in the making.
01:25:41Which one of these
01:25:43is the greatest threat to our way of life?
01:25:46Pay attention to all of them
01:25:49because there are probably
01:25:52so many that it's going to take
01:25:54a diverse, open-minded
01:25:56and fantastically curious civilization
01:26:00to even deal with the ones we can spot.
01:26:03And it's going to take
01:26:05a resilient and robust civilization
01:26:08to deal with the ones
01:26:10that hit us out of the dark.
01:26:13And if we're not ready,
01:26:15then we're doomed to repeat history.
01:26:19Dinosaurs were changing and evolving
01:26:22larger brain, faster animals,
01:26:25more diverse, more behaviorally complex.
01:26:28They were doing all the kinds of things
01:26:30that we think ourselves
01:26:32make mammals successful.
01:26:34But dinosaurs were doing them too.
01:26:36And if they hadn't become extinct,
01:26:38I think they would have got there
01:26:40before us in most cases.
01:26:42In other words,
01:26:44dinosaurs might still be
01:26:46the planet's ruling class.
01:26:48Thankfully, they're not.
01:26:50Otherwise, the human race
01:26:52may never have had a chance at life.
01:27:17NASA Jet Propulsion Laboratory
01:27:19California Institute of Technology