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Documentary, Secrets of the Dead - Graveyard of the Giant Beasts 2016
#GiantBeasts #AncientEarth #Documentary
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AnimalsTranscript
00:0065 million years ago, a giant meteor struck the Earth.
00:07Global temperatures plunged, and a mass extinction wiped out the dinosaurs and changed life on Earth forever.
00:15Little was known about the world that emerged after the catastrophe, but now a series of remarkable discoveries...
00:23It's a cute little skull.
00:24...has opened a window onto the creatures that sprang up to take the place of the dinosaurs.
00:29Oh, man, look at that.
00:32A coal mine rich with fossils...
00:34Oh, the preservation is amazing.
00:37...has revealed creatures familiar to us, but colossal in size.
00:42This animal essentially became dinosaur-sized.
00:46Are you ready, bud? Ready.
00:47...giant crocodiles and enormous snakes living side by side.
00:52So they were probably growing at about a foot and a half a year, and they just kept cooking.
00:56What were their strengths and weaknesses?
00:58This very, very fast maneuver is on the order of an eye blink.
01:02Let's go ahead and hit it!
01:04Oh, my gosh!
01:06Wow!
01:07Scientific analysis will help put together a picture of this hostile prehistoric world...
01:12There'd be these giant snakes preying on everything, all over the place.
01:16...to discover the strongest predator in this land filled with giants.
01:21They themselves are the only things that they fear.
01:25The gigantic meteorite that crashed into Earth caused a global catastrophe.
01:31Known as the K-T extinction event, it destroyed an estimated three-quarters of all living species.
01:41Entire ecosystems collapsed, and the mighty dinosaurs became extinct.
01:45The land of giants was over, or so it was thought.
01:49The plant and animal species that survived this post-apocalyptic world were a total mystery, until now.
01:59Today, in Colombia, South America, the Cerrejon Mining Company operates in the United States.
02:03One of the largest coal mines in the world is one of the largest coal mines in the world.
02:32They have trucks the size of two-story houses carrying coal cut from deep within the Earth's crust.
02:42But with each layer they claw away, the company edges their way further back in time.
02:49In 2003, they reached the critical layers that were laid down more than 10 million years after the extinction of the dinosaurs.
02:59What they found was stunning.
03:02Paleontologist Professor Jonathan Block rushed his research team to Colombia.
03:11John has spent his career studying this period in the Earth's geological history.
03:16It's known as the Paleocene.
03:18He realized this could be the lost world he'd been searching for.
03:23When you open that door into the world 58 million years ago where no one else has looked, you find things that no one else has found.
03:29So every time we come to Sarajon is very exciting because after coming for well over a decade, every time we come we find something new.
03:37Oh, man, look at that.
03:41Pretty cool.
03:44The scale is incredible.
03:45I mean, there's so much exposure of rock here.
03:53Hundreds of fossilized leaves were scattered in the layer, indicating the land during this time was dramatically different from the Cretaceous world of the dinosaurs.
04:02See that?
04:05Yeah, this is a leaf layer here.
04:08There's a leaf right here.
04:11We see the first evidence of avocado and ginger and chocolate and beans.
04:16You can see enough to see that this is part of a forest that's very warm.
04:23The size of the leaves that we find in these layers tells us it's also very wet.
04:27So this is consistent with a tropical forest.
04:31This is the stuff I was talking about, and it's up there, too.
04:35The impact of the meteor gave rise to an entirely new type of rainforest.
04:39John and his team wondered what animals might have lived in this swampy, humid environment.
04:46We came here to look for fossil animals.
04:50But when you're going to a place where no one has found fossils before, and you know you're taking kind of a gamble,
04:55it can be weeks before you find anything, if you find anything.
04:59But within maybe 10 or 15 minutes, we found the first bones that's our home.
05:05Yeah, well, check this out.
05:06What they found was beyond anything they could have imagined.
05:14Oh, that's really cool.
05:16Yeah.
05:16The place was rich with fossils of ancient species, but there was something noticeably different about them.
05:22You see that?
05:23Uh-huh.
05:24Their size.
05:26This was a land of giants.
05:29We're lucky to have found this.
05:31This is a big turtle.
05:33Carbonemis caphrinii was the largest freshwater turtle of its time.
05:39Today, freshwater turtles rarely exceed two feet in length.
05:42But this enormous creature was the size of a family car with a skull as large as a football.
05:50More intriguing were the signs that this giant may have been small prey to a much larger predator.
05:56The shell of Carbonemis shows us many things about its size.
06:03But another really interesting feature are these puncture marks.
06:06You can see them here, there, and throughout the shell.
06:09From these puncture marks, we can see that the turtle was probably bit many times throughout its life.
06:14The fact that we can see so many bite marks on the carapace might tell us one of the reasons why these side-necked turtles would have had so much thicker shells than what we see today.
06:27These puncture marks indicate something much larger was lurking in the swamps.
06:34With a bite so powerful, it could pierce a thick armored shell.
06:46The scientists quickly found evidence of the species responsible for the attacks.
06:51Uh-oh.
06:52What is this?
06:53But these were juveniles.
06:57It's a cute little skull.
07:00Ah, yeah, look at that.
07:02We didn't know what they were at first.
07:03It became pretty clear after a day of collecting that we had fossil crocodile relatives.
07:10What you're looking at here are the two eyes and then two holes on the top of the skull.
07:15Didn't make it to maturity.
07:17The mine was crawling with ancient crocodiles.
07:20Each piece of fossilized bone was carefully packed and shipped back to John's lab in Florida.
07:27See that?
07:29Ah, yeah.
07:29There, Dr. Alex Hastings, a member of John's team, was racing to catalog all the finds as they poured into the lab from Columbia.
07:40In the beginning, dozens and dozens and then hundreds more of these fossils were coming in.
07:45And getting a chance to unwrap these things and kind of start piecing everything together was great.
07:53The team found different crocodilian species, including the culprit responsible for attacking the turtles.
08:00This is the short-snouted one, or the turtle chomper.
08:03Several large turtle shells from the Sarjone site that have marks that fit very well with the teeth of this individual crocodile.
08:14But the largest croc they found was a species called Acherontesuchus.
08:19It was no bigger than today's crocs.
08:22A surprise given how large the snakes and turtles were.
08:26Acherontesuchus could have gotten to somewhere between 15 and 21 feet.
08:30Now, this is really on the upper bound of crocodilians today.
08:37Given the extent of the wounds found on the giant turtle, there was the suspicion that somewhere in the Sarjone mine, there lurked an even larger predator.
08:48Crocodiles are as old as the dinosaurs.
08:51The first evolved around 200 million years ago, at the start of the Jurassic era, and 145 million years before the period John studies.
09:00The largest crocodile that ever lived was called Sarcosuchus.
09:05Up to 40 feet in length, this 8-ton monster held its own in the age of the dinosaurs.
09:12So far, Sarjone seemed to suggest that crocodiles of this size died out with Tyrannosaurus rex.
09:21John's team soon found another colossal bone.
09:24But was it from a crocodile or some other giant monster?
09:32There were so many bones to pick up that we didn't always identify everything properly that we collected.
09:39Picking up a bone, and I remember talking to a student about it at that time, and we looked at it, and we weren't exactly sure what it was.
09:46So I wrapped it up in our paper and tape, and put a field number on it, and wrote, crocodile, question mark.
09:55Late at night, it's just kind of unraveling these things.
09:58Most of them were crocodilians, but there were a handful of bones there that were clearly not any crocodilian.
10:04The whole structure of the vertebrae was completely different.
10:06Alex and a fellow student recognized that although it was the size of a crocodile vertebrae, it actually belonged to a snake.
10:17Not only, you know, a really big snake, but being bigger than any snake we knew of.
10:22And we immediately started pulling out skeletons of anacondas and pythons and finding anything we could about giant snakes.
10:29And every single thing we were finding was smaller than what we were looking at.
10:33This bone right here.
10:36Anacondas are the largest snakes alive today, but their vertebrae are dwarfed when placed next to that of the Serajón monster.
10:46We realized that the bones that we had in our hands were much larger than anything that had ever been described before.
10:53In fact, so much larger that I had all kinds of wild ideas right away about how large that snake would have been.
11:00And so that's when I contacted the world's expert in calculating body size in the largest fossil snakes.
11:06That scientist was Dr. Jason Head, and what he was about to see would redefine the concept of the giant snake.
11:19John video chatted me one day and said, I have a giant snake. You have to see this. It's amazing.
11:28And I said, you know, I've seen snakes that are supposed to be giant snakes, and they never turn out to be as big as you say they're going to be.
11:35So, sure, you know, show me the snake.
11:37And then he came back holding a giant vertebra, and he put it right up on the camera.
11:40And at that point, I got very excited, and I bought a plane ticket and went down there.
11:46So, when I came in the next morning, I ran into Jason, and he looked at me with kind of wild eyes and said,
11:51This animal is going to reset everything we know about what it truly means to be a giant snake.
12:00The sheer size of the snake was hard to comprehend.
12:03We started to get body size estimates that were really astounding.
12:11I was really worried that we were doing the math wrong.
12:14And so, we went back and we did the math over and over and over again.
12:18And every time, it kept giving us the same massive length.
12:22So, after a while, I simply had to accept the fact that this animal was almost 50 feet long.
12:33Weighing more than a ton, this giant snake was five times bigger than the largest alive today.
12:42They named this new python Titanoboa.
12:53When they published their findings in 2009, the discovery of the snake made headlines around the world.
12:59Little did they know that there was another monster lurking out there, waiting to be discovered.
13:14Fossils in the coal mines of Cerrojón revealed that giant aquatic reptiles filled the ecological void left by the dinosaurs.
13:23What was it about these creatures that allowed them to thrive?
13:26In the extreme winter that followed the meteor impact, global temperatures plummeted.
13:36Turtles, snakes, and crocodiles were able to scavenge and gorge on the dead carcasses, and then go for months without food.
13:44Being cold-blooded gave them an advantage, allowing them to sit out the disaster.
13:49Eventually, nature found a way to restore its delicate balance into a world that was very different from the one their ancestors had left behind.
14:01It took a while for that ecosystem to recover from that extinction event.
14:06And what we see here in this forest is similar in some ways to what we find in Cerrojón.
14:12And as temperatures rose again, a 43-foot-long snake dominated the swampy world.
14:24It probably almost never left the water.
14:26I think this animal would have had a hard time breathing on land, just hanging around on the bottom for the most part, waiting for food.
14:32I think it would be very hard to have killed Titanoboa.
14:35Snakes are not easy to kill, actually, in general.
14:37They're pretty rugged animals.
14:40They're pretty tough.
14:41And when they're 43 feet long, they're probably extremely hard to kill.
14:46Our hypothesis going forward about the ecology of Cerrojón is that Titanoboa is the apex predator.
14:52For years, scientists believed Titanoboa was the apex predator of the Cerrojón swamp, until Jonathan Block called on one of his top graduate students for help.
15:09Aldo Rincon's expert eye scanned the mine for more huge bones, and it wasn't long before he found one.
15:16It wasn't a snake bone, but it was large enough to have existed during the era of the dinosaurs.
15:24Yeah, we need to try to get out of these channels.
15:27Is it there or towards Jason?
15:29Yeah, you're right.
15:30It definitely starts looking better over here.
15:32My first guess was, I mean, it looks like a dinosaur.
15:35Yeah, maybe in some of these channels or something, it might stand a chance.
15:38But we knew that there are no dinosaurs in here, so, I mean, that was pretty exciting, but at the same time, it was pretty confusing.
15:44Could it be that Aldo had unearthed the beast responsible for attacking the giant turtles?
15:57In Florida, Alex Hastings got a look at the newly discovered bone and immediately realized it belonged to a crocodile and could rewrite history.
16:07And it's just amazing to kind of unravel this thing and have something that you know is way, way larger than anything else.
16:19But it's frustrating because it's just this kind of tantalizing clue that there is this massive, massive crocodilian there.
16:27So, we know at least one of these guys got to be really, really big.
16:34Alex suspected this bone was evidence that giant crocodiles were not destroyed by the KT event, but survived into the new era.
16:43First, he needed to know more about this bone.
16:47Where precisely did it fit into the crocodile skeleton?
16:51And did it belong to an adult or a juvenile?
16:55To find out, he headed to the University of Chicago, home to America's only fossils of Sarcosuchus,
17:02the prehistoric crocodile from the dinosaur era, still believed to be the largest to have existed.
17:14The university is also home to Paul Serino, a leading expert on these prehistoric giants.
17:21The Sarkosuchus is the best known of the giant crocodilians.
17:32In terms of feet, we're talking about 40 feet long.
17:39Seeing the fossil for the first time, Professor Serino realized the Cerroon croc could be on a scale to match the Sarkosuchus.
17:50Big for a croc.
17:51Very big.
17:53It's a great specimen.
17:55It looks like it's getting close to maturity.
17:57You know, with all the parts, it would be, I suppose, about that tall and have a vertebra about that wide.
18:02Yeah, it definitely extends quite a bit longer.
18:05I got a 12-foot alligator upstairs that looks tiny compared to this.
18:08Yeah.
18:12This giant crocodile is really fantastic.
18:14It's a window onto a time that we have very little information about.
18:17So this is really of great interest that there might be a lineage that also survived the KT boundary that we don't know about.
18:29This is from a dorsal series.
18:31I'm thinking just kind of a little back behind the neck, somewhere in the ribcage area.
18:37The vertebrae from Columbia is a large croc.
18:43How large, I think we need to determine.
18:46We'll take this to the scanner and it'll be interesting to compare.
18:52The first step was to scan the partial bone to get an accurate picture of the precise shape of the original vertebrae.
19:05The vertebrae vary in size and shape.
19:07By making a direct comparison with bones from a similar position in the spine, they can predict the exact size of the Serajón crocodile.
19:19The reason we're doing this is to help us understand better where in the vertebral column, where in the backbone, this one fossil from Columbia fits in.
19:28So it's important to have something that's very large to compare to, to get a more accurate idea of how big the fossil one was.
19:37The scan also allowed them to see inside the bone, where the internal structure and density would tell them the age of the creature, whether it belonged to a small juvenile or a fully grown adult.
19:48Great. Well, let's get these scanned.
19:50Yeah.
19:50Seeing Paul's reaction to it, knowing that he's already very familiar with Sarkasuchus, is kind of confirming that we know we're definitely in that really, really big croc territory.
20:04The early signs suggest this could be a new giant croc species.
20:16What allowed these creatures to grow to such a gargantuan size?
20:20Scientists found a clue not in animal fossils, but in those left by plants.
20:30This leaf here is what's called a smooth or complete margin leaf, and it's got a very continuous outer margin to the shape.
20:37And this is a serrated or jagged margin tooth.
20:40There, it's got serrations almost like a knife.
20:42Most of the fossil leaves in Serajón were smooth-edged, allowing them to retain moisture in a hot environment.
20:48The leaves confirmed Jason's suspicions that Serajón was around four degrees hotter than rainforests today.
20:55It would have been constantly raining and very wet, incredibly hot and humid all the time.
21:02Cold-blooded animals like snakes rely on external factors to set their body temperature.
21:08In warm environments, they're able to expend more energy.
21:11In the heat of the swamps, Titanoboa would have been hunting and eating its way to its gigantic size.
21:19But what about the ancient crocs?
21:28Dr. Greg Erickson is one of the world's leading experts in crocodilians.
21:33This aggressive alligator was culled to protect the public, but beneath its skin lays a clue to its ancestors' great size.
21:42So this is essentially a very armored animal, but there's more to these osteoderms than meets the eye.
21:49What you would see if we cleaned the skin off of this is something like this, and this is an osteoderm.
21:55The hard, bony osteoderms protect the crocodile's vulnerable back, but they also contain hidden information about the growth rate of the animal.
22:04These animals lay down annual growth lines in their bones, and the osteoderms preserve them.
22:13It's pretty much like the growth rings in a tree.
22:16In the case of giant crocodilians, it's possible to figure out how they became giants.
22:23Dr. Erickson carefully slices off a tiny sliver from the alligator's osteoderm.
22:31Voila.
22:33See how we did.
22:34Well, we've got our osteoderm under a microscope, and lo and behold, we can see the annual growth lines.
22:44This last growth line was the one that was laid down just before it died.
22:48Its younger growth lines are back here, and they're much broader, and we would expect that.
22:52That's when an animal's young.
22:54It's essentially its teenage years and growing like crazy.
22:57There's 15, maybe even 20, like you see right there.
22:59These animals usually mature between 12 and 15 years of age, and they start plateauing their growth, and you can see how the growth lines start getting tighter and tighter towards the periphery, so its growth was slowing at that point.
23:12This mature alligator has 15 growth rings, one for each year before it reached adulthood.
23:20However, when Greg compares this to an osteoderm from the giant croc, Sarcosuchus, there is a striking difference.
23:30The difference is this osteoderm has 55 to 60 of these growth bands packed in there, so this animal essentially became dinosaur-sized instead of plateauing at, say, 20 years.
23:43As you might see, an American alligator, these animals plateaued their growth at maybe 40, 45 years of age, and so they were probably growing at about a foot and a half a year, and they just kept cooking.
23:55The secret to crocodilian giantism is simply prolonging the timing to maturity.
24:02So it's likely that the Sarajon croc was able to delay its maturity, allowing it to grow to a fearsome size.
24:09But exactly how big?
24:13The scan will generate three-dimensional images and allow the scientists to see inside these giant relics for the very first time.
24:36Looks like a great scan.
24:37Yeah.
24:38It's going to be beautiful when it's done.
24:40Good.
24:41Ah, that's cool.
24:43You've got the form of any internal structure of the bone now, so you can make a comparison.
24:49The shape will confirm where the bone sat in the croc's spine, and the density will help determine whether it's a fully grown adult or just a juvenile, with a lot of growing still to do.
24:59So much detail.
25:01Yeah.
25:01It's going to be fantastic to go through.
25:03That could be a preservation thing in the Sarajon one, so it might have just been more infilled with sediment and the fossilization process.
25:12Great to see the CT scanning.
25:14The surfaces look fantastic.
25:17There will be a lot of numbers to crunch to really get the answer for how big exactly it was.
25:22Yeah, let's see.
25:25Let's go through that, the one, the Sarajon specimen.
25:29This one?
25:29Yeah.
25:30This new bone suggests that the prehistoric swamps of Serahol were a world unlike any other.
25:38A unique environment filled with reptiles of an astonishing scale, and one where a giant crocodile and colossal snake both inhabit the same ecosystem.
25:50All the evidence indicates that whenever snakes and crocodiles hunt in the same quarters, it ends in conflict.
25:57The Florida Everglades provide a wet and humid habitat where descendants of the Sarajon giants live and hunt in the same territory.
26:10The indigenous American alligator and the invasive Burmese python.
26:16Research ecologist Kristen Hart is charged with capturing the disruptive pest using a GPS and radio tracking system.
26:29We know for a fact these Burmese pythons came here because of the pet trade.
26:33They were nice pets for people, and they got really big, really fast, and they were too much to handle.
26:39So instead of putting your pet down, they may have come and released it in a nice environment like the Everglades.
26:44We're very close to the animal.
26:45So the python is a damaging critter for the Everglades because it does compete with the alligator as a top consumer in the food chain.
26:55In these ideal conditions, the snake population has exploded, leading to a shortage of food and violent clashes.
27:04Kristen's radio transmitters uncovered evidence that the two predators are turning on each other.
27:21We were tracking one of our radio-type pythons, and the signal was clearly in the alligator because as the alligator started to move away from us, the signal got weaker and weaker as the alligator got further away.
27:34So we know from that instance that the alligator actually consumed the python.
27:40We have definite evidence from stomach content analyses that pythons do consume alligators.
27:44I don't know of too many other places where you have crocodilians and large constrictors consuming each other.
27:50Today, sightings of hungry pythons taking on much larger alligators are not uncommon.
27:58This battle between a large Burmese python and a juvenile alligator was captured on video.
28:13It took the python more than three hours to constrict and eat the alligator.
28:30And this fossil reveals the same battle raged millions of years ago.
28:35It's hard to see, but nestling in the stomach of this fossil snake is a baby crocodile.
28:45It is clear that in the murky swamps of the Cerrojón, the giant snake and the mega croc would inevitably have come into conflict.
28:54But which one would triumph?
28:57By looking at their living relatives, we can piece together how these two killers used their impressive array of weapons.
29:05Snake expert David Penning demonstrates one of the snake's formidable tools.
29:19The thermal equivalent of vision.
29:28So a snake has a whole other world that it sees than what we do.
29:33So not only can they see something visually, they can also pick up the heat signature of it.
29:39This super sense allows some snakes to see their prey literally in a different light.
29:46David is going to demonstrate how.
29:48So today we're going to try a thermal experiment.
29:51Many boas and pythons have external pits and nerve endings in their head that allows them to actually perceive infrared or thermal energy.
30:00So we're going to use a snake that has pits.
30:03I'm actually going to cover her so that she doesn't feel like exploring.
30:07So what we have here are two different gloves with two different temperatures.
30:11This is a glove filled with hot water, and this is a glove filled with cold water.
30:14So we can't see the difference.
30:16She can.
30:16She has an infrared sensing system that can differentiate between temperatures.
30:21So this snake will be presented with two gloves that look alike and are moving similarly, but are very different in temperature.
30:29It's in a low light situation, so snakes are more likely going to be relying on their infrared sensing capacities to make a choice between which object to strike at.
30:38We don't have this system.
30:39She does.
30:40She's going to be perceiving infrared energy.
30:43We can't.
30:44Chances are it'll make the decision for the hot glove.
30:47And there she goes.
30:52And when offered these two gloves, she's orienting towards and striking at the warm ones.
30:59Using its heat sensors, the snake can detect its prey without even seeing it.
31:04Then it's only a matter of seconds before it launches its deadly strike.
31:08So in many boas and pythons, they have heat sensing pits in their labial scales around their lips.
31:21And what those are, are extensions of the trigeminal nerve.
31:26The nerve actually comes out and is in the base of those pits.
31:30So those are free nerve endings that interpret infrared heat.
31:34They're constantly, you can think of it almost like a Geiger counter, they're constantly ticking.
31:38So the snake is experiencing a nerve impulse.
31:41About 13 to 30 times a second, the nerves are firing.
31:45But when an infrared image or a hot object is put in front of it, it starts to increase.
31:50And so it sends a signal back to the brain that allows them to see a thermal image of their prey.
31:55And just like boas today, titanoboa would have used the same capabilities to hunt.
32:02This super sense made it an expert at ambushing prey.
32:05But the croc is equipped with its own unique tracking device.
32:28Dr. Erickson understands what makes these carnivorous beings so skilled at pursuing their quarry.
32:35The architecture of a croculean head is just amazing how sophisticated this is.
32:43Just a remarkable killing machine.
32:46These killing machines have an incredible tool.
32:49Dome pressure sensors.
32:52Thousands of tiny dots sprinkled around the mouth that act as built-in radar.
32:57Directing the beast toward its target.
32:59See, there was an animal splashing in the water over there.
33:02The pressure waves in the water would hit the face of this animal.
33:07It would go down through the dome pressure sensors and basically register with the brain that,
33:10hey, there's something going on over here.
33:12This animal will make its way over there.
33:15So it's a really remarkable sensing device.
33:18These sensors allow the crocodile to sit stealthily beneath the water's surface
33:23before attacking its unsuspecting prey.
33:30Dome pressure sensors are features found only in crocodilians.
33:35The architecture of those structures are completely unique to the animal kingdom.
33:40Back in Louisiana, David Penning is trying to measure something that has never been measured before.
34:02He's going to calculate the strike speed of Titanoboa.
34:05We don't have a snake alive today the size of Titanoboa.
34:10What we do have are snakes of different sizes alive today.
34:14We estimate what Titanoboa can do based on what living snakes today can do.
34:21Snakes are incredibly difficult to see in the wild.
34:25They move slowly toward their prey, getting as close as possible before striking.
34:29When they do, as David demonstrates with a dead mouse, it's with ferocious speed.
34:38The strike that we just saw here by this red-tailed boa was probably on the order of 50 to 100 milliseconds.
34:44So this snake starts a strike and comes in contact with the prey before the prey even has the ability to send a signal saying something might be a threat.
34:56Many snakes have the ability to reach their target before their target is even aware of the fact that something just happened.
35:02Like its modern descendants, Titanoboa was a constrictor, and it would have used the same tactics to surprise its prey.
35:17It was likely striking at prey from only about a half a meter away, and that's because it's waiting for prey to get close.
35:23And a half a meter is a considerable distance, but not when you're something the size of Titanoboa.
35:27Having amassed a comprehensive data set of size versus speed, David is now able to speculate how fast Titanoboa could strike its prey.
35:410.1 to 0.2 seconds.
35:440.2 seconds is on the order of an eye blink.
35:47So this is still a very, very fast maneuver.
35:51These values are within the range of what we would expect from smaller snakes,
35:54but that actually makes it more impressive considering the size of what this animal had to move towards a prey item.
36:01Titanoboa accelerated on average 150 meters per second squared during their strikes.
36:07Humans pass out at about 50 meters per second squared.
36:13This incredible speed exerts a force 15 times greater than gravity.
36:17If the human body accelerated at this speed, we would almost certainly suffer brain damage.
36:24So we're talking about impact pressures, similar to what we see in impacts with bullets shot.
36:30The strike speed of this giant snake is truly terrifying, but the giant crocodile was hardly slow.
36:37The secret behind the crocodile's attack speed was its muscular tail that propelled it towards its prey.
36:52Crocodilians swim sinuously, moving their tail back and forth.
36:57But if they need burst speed, they can do it very powerfully.
37:01This massive tail is the secret to the incredible acceleration these animals can do.
37:12This is what creates the propulsion.
37:16Some of them can leap out of the water.
37:18Most crocodilians can seize prey within about two-thirds of their total body length.
37:25So the bigger the crocodile, the more powerful its acceleration.
37:28Up to 40 feet per second.
37:32Or its full body length in the blink of an eye.
37:36But stealth is just the beginning.
37:39Once the prey is caught, the two predators use very different techniques to kill.
37:45The crocodile's greatest weapon is its powerful jaws.
37:51How can bite force be estimated for an animal that lived 58 million years ago?
37:58One of Dr. Erickson's ongoing studies is the relationship between a crocodile's size and the power of its bite.
38:09He carries out his research at an alligator sanctuary in Alabama.
38:14Here, well-fed gators are used to interacting with people.
38:18We'll start with him.
38:21I think he'll give us a good bite.
38:24Crocodilians have been, you know, the guardians of the water-land interface for 85 million years.
38:28And the secrets to their success, or a lot of it, comes from their feeding abilities.
38:33Yeah, we're going to need, uh, four, six, seven people.
38:36It's routine procedure for these gators, yet still extraordinarily dangerous for the team.
38:48Ready to make it happen?
38:50It's going to take quite a few, a small army of handlers to get that animal over to here so we can test it.
38:55So, we'll see how it goes.
38:57Let me get the rope on him, see what kind of mood he's in.
39:00You got any smaller ones?
39:01We want to get this strap right at the back of the head, trying to get the head pin down.
39:09And then, of course, do the rest of them.
39:11Hey, come here. Up here, up here, up here.
39:13Up here.
39:15Come on.
39:17All right, Doc, pull it.
39:18You got him.
39:19Oh, and we're there.
39:21Okay, go.
39:22All right.
39:30He's got the rope, he's got the rope.
39:31Oh, get slack.
39:31Give me some slack.
39:32Let him back up a little bit, and we'll do it again.
39:40All right.
39:40Come on.
39:41Get ready.
39:46All right.
39:48All right, let's get in front.
39:54All right, go.
39:55Okay, get on the head.
39:59Got a foot.
40:00But even experienced gator handlers can be caught off guard by sheer brute strength.
40:06The last one to go is this one.
40:09Oh, you came with it?
40:10Yep, I'm good.
40:12Caught me off balance.
40:14What I'll do is I'll insert this flat plate into the mouth of the alligator.
40:19As soon as this plate touches the teeth, the animal is going to slam it.
40:23It enlicits a very, very forceful bite.
40:28As that plate's compressed, it's going to give us an electrical readout that tells us how much force was involved during that particular bite.
40:35All right.
40:39Okay.
40:40All right.
40:43Ready?
40:44Come on.
40:46Come on.
40:48There's a good one.
40:50Oh, Jesus.
40:50Two thousand, four hundred and thirty-one pounds.
40:53Oh!
40:53Wow.
40:54Wow.
40:55Awesome.
40:56Over a ton of bite force.
40:58Pretty cool, wasn't it?
40:59That was awesome.
41:00What these animals do is they sink their teeth into the hide of large game and get a purchase on it.
41:08Then they work the animal out into the water, use their great mass, and just submerge the animal and drown them.
41:13If that animal starts struggling and getting out of the jaws, they'll reassert their bite again.
41:21The real secret's right there, those mussels, pterygoid mussels, and you'll see those contract.
41:25This is really the engine behind this creature.
41:27Sixty percent of the bite force comes from right here.
41:30That's not the neck.
41:31That's actually jaw muscles that are billowing out of the back.
41:34I think this mimics prey that are struggling in their mouth if they want to reassert their bites.
41:39Let's see if it bites again here.
41:41There it is.
41:42Nice clinch.
41:43That was 1,544 pounds.
41:47That's without slamming the jaws.
41:49That's just from a dead start.
41:51It's like a high horsepower engine or something.
41:54Boom.
41:57It's going to pop less.
42:00Greg's study proves the power of a crocodile's bite is proportional to its size.
42:06Wow.
42:07Really hammered it.
42:13He's just being as cooperative as he's going to get.
42:15This alligator's 11 foot 6, but it fought like a 13-5, I'll tell you.
42:20It gave us a heck of a run.
42:23I liken this to being kind of like bull riding for scientists.
42:28All right.
42:30Once Alex Hastings gives Greg an accurate size for the Cerrojón crocodile...
42:35Good boy.
42:35...he will then be able to estimate the power in the beast's bite.
42:39All right.
42:45But Titanoboa was far from defenseless.
42:49As a constrictor, it was able to exert crushing force.
42:53Just how strong was our prehistoric giant?
42:56David Penning has spent years studying the constriction strength of snakes.
43:07Now he's going to apply the same expert analysis to estimate Titanoboa's crushing power.
43:13We are going to be testing 400 to 500 snakes to predict what Titanoboa could have done.
43:20That's the largest data set on constriction performance on the planet.
43:24By fixing sensors to the snake's meal of a dead rabbit,
43:27David will be able to measure how much pressure this comparatively small constrictor can exert.
43:33We are recording.
43:34We are recording.
43:433.2 pounds per square inch is more than enough pressure to kill even larger animals.
44:05But how does that compare to the pressure Titanoboa could apply?
44:09She is probably 15 feet and 3 or 4 inches.
44:12And so from that length, if we know that she's 15 feet and Titanoboa could get upwards into the 30 and 40 foot range,
44:21and she squeezes with a certain pressure,
44:23and we know what smaller snakes and other snakes her size can squeeze,
44:26we can infer what Titanoboa could have done.
44:29Armed with the results of the constriction tests,
44:32David reveals the unparalleled power of the snake's gigantic ancestor.
44:37Titanoboa likely squeezed with a constriction pressure ranging from 50 to 250 pounds per square inch.
44:46That's 250 pounds of pressure exerted on every inch of contact with the prey's body.
44:53But when David estimates the total pressure, the potential force is truly terrifying.
44:58On the high end of the estimates, we're looking at 1.3 million pounds of force.
45:04A tank weighs about 150,000 pounds.
45:07And so we're almost an order of magnitude greater than the weight of a tank.
45:11That is just frankly not survivable.
45:13But David Penning's research has thrown up another surprise that casts light on precisely how Titanoboa killed its prey.
45:24It has long been believed that snakes constrict their prey until they suffocate.
45:29But David's latest data suggests the kill is far more efficient.
45:35By studying the internal damage to the prey,
45:38David has discovered that an entirely different phenomenon kills the animal.
45:43The force of constriction induces what's called a red-out,
45:50what animals experience when the brain is under a massive amount of physical pressure.
45:58We see these effects in prey.
46:02So not only is their heart having problems pumping blood,
46:06you now have approximately half or a third ear blood above that coil,
46:10and pressure's being pushed here.
46:11That fluid has to go somewhere, and that somewhere is in your brain.
46:16Applying the equivalent pressure of several military tanks floods the animal's brain with blood.
46:24It's forcing blood towards the only exit, which are the eyes, the nose, and the mouth.
46:29The force exerted by Titanoboa would most likely have induced a brain hemorrhage in its victims.
46:43I've checked it several times.
46:45If Titanoboa is squeezed with the pressures that we predict,
46:48I don't think there's any animal on the planet that would survive something like that.
46:51It's absolutely incredible.
46:52At the University of Chicago, Alex Hastings finally has the details he needs
47:08to estimate the size and age of the crocodile fossil.
47:11The first surprise is that the bone was not from the lower back near the tail, but is near the neck.
47:23But was it a fully grown adult or a developing juvenile?
47:26The CT scans were amazing.
47:31The level of detail is unbelievable.
47:35You kind of see a little more of a spongy kind of texture in juvenile bones
47:39that you see a much more solid, firm texture in the adults.
47:43This is another kind of indicator that Fossil from Sarajon was likely an adult individual.
47:47The Sarajon crocodile was a young adult.
47:51But more importantly, it was of a size to match the croc from the dinosaur era, Sarcosuchus.
47:58The Sarajon croc came out to be about 8.63 meters, which is about 28 feet.
48:04That is an enormous croc.
48:06It's bigger than any crocodile that we have alive today.
48:09This behemoth of the swamps was almost 30 feet long, 3 feet high, and weighed 3 tons.
48:19Proof at last that the giant crocodilians did survive the catastrophe that wiped out the dinosaurs.
48:27These two colossal reptiles achieved a scale not seen since the days of the dinosaur.
48:39Now that we know how large the croc was,
48:51Dr. Greg Erickson can finally estimate the power of its monstrous bite.
48:56It is of a magnitude equal to that of a T-Rex.
49:01When we're talking about a 15,000-pound bite force,
49:04we're talking about twice what any living crocodile could do.
49:09To demonstrate this crushing power,
49:15they will use the skull of an adult cow to see how it might fare in an attack.
49:23Well, yeah, pretty science-y.
49:26Yeah.
49:27I suspect that a crocodile that could generate 15,000 pounds of bite force
49:31could pretty much crush just about any animal it got a hold of.
49:34We've got a cattle skull here, and we're going to take a mechanical loading frame.
49:42This is a device that engineers use to test the strength of structures and materials.
49:48They'll also be taking the data, and we'll get a force displacement curve.
49:52And from that, we can see when the structure started failing.
49:57And it's still hitting. It's hitting on this side.
49:59You've got to watch it tilting.
50:01They're going to exert 15,000 pounds of pressure on this cow skull,
50:06second only to an elephant skull in strength.
50:09A little bit. Yeah, I think it went.
50:12So we're ready to conduct our test.
50:14We'll see what happens.
50:16You ready, Bob?
50:17Ready.
50:17Okay, let's go ahead and hit it.
50:27Oh, my gosh.
50:29Wow.
50:30No, I just blew it up.
50:33Amazing.
50:35Wow.
50:36How much force?
50:383,000 pounds.
50:40The skull is obliterated when just a fraction of the ancient croc's ferocious power is applied.
50:53I feel like I'm crawling through the wreckage here.
50:56So that was a demonstration of just 3,000 pounds of force.
51:00So imagine five times that.
51:03I mean, this thing was one of the ultimate killing machines.
51:07Oh, my gosh.
51:11Wow.
51:13We now know the croc's bite force was of a magnitude not seen since the age of dinosaurs.
51:22I don't think any animal in this creature's realm was safe.
51:27I mean, this is a dangerous creature.
51:28Oh, my goodness.
51:35Yeah, that definitely broke that thing.
51:39That's bite force.
51:40Ha, ha, ha, ha.
51:48By studying the attack capabilities of the smaller descendants of these prehistoric giants,
51:53we have been able to piece together the incredible powers of these fearsome predators.
51:59Juveniles would always be vulnerable to other species.
52:02But when two adults went head to head, which would become the apex predator?
52:08It's a question of who's going to have the upper hand.
52:10Would the snake be able to coil around and or engulf the crocodile before it would have a chance?
52:16With a stranglehold more crushing than the weight of several military tanks,
52:21Titanoboa's size alone might have given it the advantage.
52:25There's not a single animal that could have survived being constricted by those coils.
52:33But if the crocodile struck first, a bite force of 15,000 pounds per square inch would be more than enough to kill anything.
52:40Oh, my gosh. Wow.
52:46If you are in the territory of battle of a crocodilian, you don't stand a chance.
52:52In the end, it isn't how the creatures kill that settles the debate.
52:57It's how they eat.
53:00Snakes can't actually purchase prey with arms, and they don't chew.
53:05They don't rip their prey apart and chew pieces of it.
53:07They're basically walking their body over the prey.
53:11So those large jaws can swing out, and there's a big mass of soft tissue that can actually expand and create a massive gape.
53:18So for a Titanoboa with a skull, say, about this big, a gape would have exceeded two meters in total size.
53:23Big enough to swallow any of the other vertebrates we find at Serhunt.
53:27This ability allows this 12-foot Florida python to consume prey that would have been too large for other predators.
53:34But there are limits to what it could digest.
53:37The question becomes, could it have fitted in its stomach?
53:40And from the data that we have today, the largest prey that something like Titanoboa would have been taking was 60% of its own body mass.
53:49Would the Serhunt croc's size have ruptured the snake's belly?
53:54It's this detail that decides the outcome.
53:57For despite Titanoboa's larger size, the adult croc was too big for the snake.
54:02Crocodiles, however, do not need to swallow their prey whole.
54:07They rip it into pieces.
54:08In the six years since its fossil was discovered, scientists thought Titanoboa dominated this little-known era exclusively.
54:22But this land of giants has a new ruler, a crocodile with the size and force to outrank its rival.
54:33Serhunt has a new apex predator.
54:37To find something that amazing that both tells us so much about the natural world, it is a constant reminder to me of just what we don't know about the planet.
54:58Who knows what's still to be found in these different types of environments?
55:04I think we're right at the beginning of understanding.
55:10This program is available on DVD.
55:13To order, visit shoppbs.org or call 1-800-PLAY-PBS.
55:18To order, visit shoppbs.com or call 1-800-PLAY-PBS.
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