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Documentary, Megalodon - Prehistoric Predators
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AnimalsTranscript
00:00Sharks. The most dangerous and feared predators in the ocean.
00:07But even the great white pales in comparison to the biggest shark that ever lived.
00:15Megalodon. Literally translated it means big tooth.
00:20A prehistoric shark with three meter jaws lined with deadly rows of serrated teeth.
00:26Megalodon used these jaws to inflict massive damage on even the biggest whales in the ocean.
00:33Its teeth were huge.
00:38Six to maybe seven inches long, wickedly serrated on either side like steak knives and shaped like a big broad triangle.
00:45Now, two million years after the last Megalodon mysteriously disappeared from the fossil record,
00:53scientists are investigating the true shape, size and behavior of one of the most fearsome predators in history.
01:02SEA WATER COVERS ALMOST 70% OF THE EARTH'S SURFACE.
01:09This is where life on our planet first began.
01:14And some of these early underwater creatures were big predatory fish.
01:20Giant squid, stingrays, toothed whales and other dangerous predators have long roamed the sea.
01:27And 300 million years before T-Rex took its first bite, an apex predator was scouring the watery depths.
01:34the shark.
01:45The shark.
01:49the watery depths. The shark.
02:00Paleontologists have found remarkable fossil evidence of these predators going
02:05back more than 400 million years. The biology of these sharks has remained
02:10remarkably stable for all this time.
02:16If you look at a shark from, say, 350 million years ago, you'd have no trouble
02:21identifying that as a shark. It might have some differences with what we think of
02:25as the conventional look of sharks today, but you would not be confused.
02:29You would know right away that you were looking at a shark.
02:34Although many of these prehistoric sharks are now extinct, the great white shark,
02:39which still roams the sea today, has survived more than 10 million years.
02:45It has become the ultimate ocean predator.
03:02But the great white paled in comparison to another giant shark that ruled the seven seas,
03:08dominating every other predator in the ocean.
03:12Megalodon. Literally translated, it means big tooth.
03:19Megalodon was a giant fossil shark, lived from maybe 25 million years ago up to about 2 million years ago.
03:26The largest oceanic predatory shark that we are aware of in the fossil record.
03:31Fantastic, huge, enormous predator that the likes of which the oceans hadn't seen before or since.
03:42It was one of the biggest predators of all time.
03:45You've got these massive razor blade sharp teeth attached to an animal the size of a greyhound bus.
03:51I mean, this was the ultimate predator.
03:54Never has an apex predator made such a huge mark on the planet, only to leave so little trace of itself behind.
04:04It's like the ultimate detective story.
04:06We truly don't know exactly what the Megalodon looked like.
04:09We can only assume how it looked and how it killed.
04:12In order to solve this mystery, scientists need fossil evidence.
04:18But in the case of Megalodon, there are no skeletons left to study.
04:23This presents a major challenge to researchers.
04:27All creatures, in the sea or on land, begin to decompose and fall apart the moment they die.
04:34For those with skeletons, within a short period of time, all that is left are the bones.
04:40But when it comes to Megalodon, there's a hitch.
04:43A shark's skeleton is constructed almost entirely of cartilage.
04:47Consequently, there are very few fossilized remains left to show scientists the size and shape of this gigantic fish.
04:56Cartilage, pliable and light, it's the balsa wood of the body.
05:02But exposed to salt water, sand and especially bacteria, Megalodon's skeleton has little staying power.
05:11The cartilage is this brownish-yellow material.
05:16That's the flexible component of the cartilaginous skeleton.
05:20You can actually see the little tiny prisms which add structural support and rigidity to the otherwise flexible cartilage.
05:28And that's what gives the skeleton its strength.
05:31However, because these individual little prisms of cartilage are held together with organic fibers,
05:39after the shark dies, those organic fibers can then decompose.
05:44Within weeks, shark cartilage breaks apart and disappears.
05:56The teeth, protected by an enamel coating, are one of only two parts of the skeleton to survive.
06:02These massive teeth are extremely long.
06:08Scientists are using them as the building blocks to reverse-engineer the giant shark.
06:14The only other known fossil remains are a few small pieces of backbone.
06:18The Calvert Cliffs, along the Chesapeake Bay in Maryland, are a well-known site for uncovering fossils of prehistoric sharks.
06:29Dr. Stephen Godfrey has been digging for fossils here for more than ten years.
06:33In that time, he has not found a single megalodon tooth.
06:38Oh yeah, this is great. The tide's way up.
06:40Along with Dr. Bretton Kent, Godfrey scours the area, searching for fossil clues.
06:46Oh, there's a shark tooth. Little one.
06:49Yep.
06:51Oh, there's some bone right here.
06:53This was for about a 12 or 14 foot long shark.
06:58The root's missing. It's just the crown.
07:01You gotta see this!
07:03After a few minutes of searching the face of the cliff, Dr. Godfrey spies something about a meter up the wall.
07:09This has never happened to me before.
07:11A big meg?
07:13Well, it's not really big, but it's a meg and it's in really nice condition.
07:17And it's just sitting there.
07:19This is so sweet. You can see the serrations on it. It's pristine.
07:22I mean, check that out.
07:24Oh, absolutely perfect. Look at that.
07:25Oh, that is gorgeous.
07:29Incredibly, on the one day cameras are there to record their fossil hunt.
07:33Godfrey extracts a rare 10 to 12 million year old Megalodon shark tooth from the clay-laden cliff.
07:40Nice upper lateral.
07:44Beautiful condition.
07:45Doesn't get any better than that.
07:47Look at that. That's incredible.
07:48That's beautiful.
07:50A gorgeous one.
07:51That's very nice.
07:52One of the interesting things about this tooth, if you notice the tip, there's a compression fracture on it.
07:58Compression fracture is when the tooth bites down vertically and strikes something hard like bone.
08:03It actually, instead of producing a flake off of the side, it actually crushes the tip to powder.
08:08And compression fractures themselves are very common on Megalodon teeth.
08:14Compression fractures and other violent accidents from biting down on their prey have resulted in a unique biological adaptation by sharks over the last 400 million years.
08:25Constant and lifelong tooth replacement.
08:27Over a 25 year lifespan, a shark will shed approximately 20,000 teeth.
08:35Other predators, such as crocodiles, also replace teeth.
08:39But to produce so many in a lifetime is a characteristic unique to the shark.
08:44The shark's mouth and gums contain an endless conveyor belt of replacement teeth, just below and above the gum line, waiting to flip forward and take their place in the front row of teeth.
08:55These Megalodon teeth can unlock a tremendous amount of information about this creature.
09:01Once you find a Megtooth, the rest is gravy. The day has been made.
09:06Yeah.
09:08With the found teeth piling up in museum collections around the world, interest in Megalodon intensified over the last few centuries.
09:16In 1909, ichthyologists and paleontologists in New York at the American Museum of Natural History labored with great effort to build what they thought was the ultimate Megalodon jaw.
09:29The finished jaw caused a sensation, showing a gaping, three-meter-high collection of nasty, sharp-edged teeth.
09:39But they'd made some crucial errors in their reconstruction that paleontologists continue to correct and refine even today.
09:45Zoologist and shark collector Dr. Gordon Hubble has been studying shark teeth and jaws for four decades.
09:54Back in the early 1900s when they reconstructed that Megalodon jaw, besides having a problem with keeping the teeth in the jaw,
10:03they didn't know the dental formula, they didn't know the dental arrangement of Megalodon, so the teeth were just put in kind of haphazardly.
10:10In constructing the display, the scientists appeared to have chosen the largest teeth available from fossil deposits around the world,
10:19and the dimensions reflected that. The jaw was enormous.
10:24The 1909 effort eventually raised questions. Would the teeth going front to back all be that large?
10:31And then there were the sheer number of teeth in the jaw. It seemed excessive.
10:35This version of Megalodon had more teeth than the modern great white.
10:41These doubts fueled an even larger debate.
10:45Is the modern great white shark the best comparison model for the size and shape of Megalodon?
10:51How closely related are these creatures from the deep?
10:54Ryan Johnson has been studying the living great white shark up close and personal in the waters off the coast of South Africa.
11:01I think when the guys discovered these huge fossilized teeth, they wanted to find something in today's world that possibly was similar.
11:12And the only real shark that springs to mind is the great white shark.
11:16And so this is why you always get this constant comparison between the great white and the Megalodon.
11:21Was the white shark just a little version of what the Megalodon was back in prehistoric times?
11:25The massive predatory great white holds a mythical place in the minds of fishermen, sailors and other sea lovers.
11:34The maximum size that a great white gets is probably among shark biologists the most debated question that is always talked about.
11:42You speak to any fisherman and he says my boat's 20 foot long and it was 2 foot that way, 2 foot that way, must be 25, 26 foot.
11:48And that's probably not the case.
11:51In truth, the largest modern great white sharks are believed to be about 6 meters long with a maximum weight around 1,800 kilograms.
12:00Megalodon is commonly thought to reach between 15 to 17 meters with an almost unimaginable weight of 45,000 kilograms.
12:09I think that comparison is pretty good between the great whites and the Megalodon.
12:14But you also must remember the only information we have about the Meg is from his teeth.
12:19I think the main similarity between the teeth of the Meg and the teeth of the great white other than their big size is probably the serrations, the triangular serrations.
12:30And what that shows immediately is that both sharks, rather than swallowing their prey whole, was taking chunks out of very big prey, possibly as big as themselves.
12:41In 1988, scientist Gordon Hubbell received a call from a fellow fossil collector about a remarkable find at a phosphate mine in Florida.
12:50Larry Martin had uncovered a set of 95 teeth from one Megalodon shark.
12:57This matched set became the holy grail of Megalodon research.
13:01They unlocked part of the mystery surrounding this astounding creature.
13:06This is the most complete set of associated Megalodon teeth that has ever been found.
13:11The reason why this is significant is that once we can arrange these teeth, we can figure out if the animal is truly related to the white shark line or if it's related to some other species of sharks.
13:26Eighty years after the first jaw was constructed, Hubbell's teeth may hold the key to understanding the true shape and size of the greatest predator the sea has ever known.
13:35Megalodon, a ferocious predator that roamed the seas for 20 million years and all that's left is the teeth and a few scattered vertebrae.
13:54In 1988, Gordon Hubbell helped to identify the most complete set of Megalodon teeth.
13:59But how did these teeth fit together inside the shark's jaw?
14:04Hubbell was stumped.
14:06It led to about 10 years of frustration because we didn't know at the time for sure what the dental formula on the Megalodon shark was.
14:15And so every time a scientist came to visit us or just anybody that wanted to look at these teeth, we had them place these teeth how they thought they would go in the mouth.
14:26The third tooth is a prominent feature in the modern great white shark's jaw line.
14:33And that's what really bothered us.
14:35It wasn't until we realized that the Megalodon is an entirely different line of evolution and does not have that third upper tooth, that small tooth that slants in, and indeed has a third upper tooth that's about the same size as the first two teeth.
14:50Then we figured it out and everything fell into place.
14:53There are 24 teeth in the upper jaw. The lower jaw has a total of 22 teeth.
15:00Behind the 46 teeth in the front row, approximately 200 more teeth lie in rows waiting to flip forward to the front and take their place on the predatory battlefield.
15:11Other scientists and museums were now interested in taking that knowledge and putting together a realistic Megalodon jaw recreation.
15:22Fossil collector John Babias has amassed a huge collection of Megalodon teeth.
15:28With the help of museum curator Brad Archer, he undertook the task of building an accurate recreation of the Megalodon jaw.
15:34No one had done the project before, at least not in the scale that we wanted.
15:40Babias and Archer worked diligently to figure out the shape and placement of the upper and lower teeth, using models and pictures of great white jaws and earlier Megalodon reconstructions.
15:50Right off the bat we figured, oh damn these teeth aren't going to fit because they're way too big and there's no room in the jaw unless the shark only had four teeth in a row and we know that's not correct.
16:00First, the teeth are sanded smooth. Next a hole is drilled in the base of the tooth and a metal rod is inserted. The rod is then attached to the jaw mold.
16:13But they still needed help placing the teeth in the jaw. The men turned to Gordon Hubbell and his knowledge of associated Megalodon tooth sets to see if he could help organize the teeth.
16:24And we looked at all the teeth that he had and we put them together into a set as closely as we could.
16:33In September of 1994, the jaws were finally completed. The men loaded the jaws onto a flatbed truck and drove them to the museum at Arizona State.
16:42The results were astounding. While not quite as large as the jaws built in New York in 1909, it's clear an animal would have to be of massive proportions to carry a set of jaws this size.
16:55Well, this jaw is approximately seven and a half feet tall and it's about eight and a half feet wide if I remember right. And it has about 254 teeth in it. All real teeth.
17:09Once scientists had an idea about the size and scale of the teeth and jaws, they could start to figure out what the body was like.
17:18The Calvert Marine Museum skeleton paints a vivid portrait of the infrastructure needed to support the massive jaws.
17:27But the next step was to create a lifelike representation of this beast. What would a creature of this size look like swimming towards you in the ocean?
17:37Dr. Michael Gottfried, who had worked on the Calvert skeleton, now felt confident he could speculate on what this beast might have looked like from the outside.
17:49Collaborating with artist and animal modeler, Jim Mellie, a make-model was born.
17:55I mean, basically, this kind of thing is the marriage of science and art, taking scientific information and converting it into a sculpture.
18:03A 15-meter, life-size replica of megalodon now hangs in the San Diego Natural History Museum.
18:12So after all the research, working with models, working with drawings, working with the actual specimens that we do have, here's the end result.
18:18What we think is the most accurate and the most biologically plausible reconstruction of megalodon that's on exhibit anywhere.
18:25From the first megtooth found by early humans, scientists now have a stunning picture of this massive creature.
18:33Hundreds of teeth capable of inflicting terrible damage on its prey.
18:38A jaw three meters wide and two meters high.
18:41A body at least 15 meters long.
18:43Megalodon was enormous in doing an estimate of the size of this fossil giant that it would probably have been about a ton of foot.
18:52So in the neighborhood of about 50 tons plus. A truly enormous animal.
18:56The question now was not so much what did the shark and its jaws look like, but how did they work?
19:08Scientists sometimes look to the biting and killing behavior of the modern great white shark to try and understand how megalodon behaved.
19:15Both sharks are thought to use the same thrusting, sawing motion to rip gaping holes in their prey during an attack.
19:26An expedition with Ryan Johnson into the shark filled waters off Maselle Bay, South Africa provides a rare glimpse of this behavior.
19:33Fresh fish liver acts as good shark bait. It's not long before the first strike.
19:43There we go. There we go.
19:50Go! Thresh it!
19:52See now you hold it and he's going to start doing his head shake.
19:55There he goes. Shake! Shake!
20:00Just a little one. See when he grasped it, he started biting.
20:04But then once he really got a hold of it, he started shaking his head back and forth.
20:07And that really what makes the white shark unique is that not only does it bite and try to grasp the stuff and swallow it,
20:14it starts thrashing his head back and forth and trying to remove pieces of the meat or the prey that it's eating.
20:24But observation from the deck of the boat is not good enough for Johnson.
20:27To get a complete understanding of how the great white swims, you need to get in the water with the shark.
20:34New audio techniques provide real-time commentary on what Johnson is seeing.
20:39All of the great white's power for swimming is coming from his tail.
20:44But what engines this is these two muscle bands, two red muscle bands that go from his body right down to his tail.
20:49And they just work like two big pistons going back and forth, back and forth.
20:54And this makes it one of the most efficient swimmers and predators in the ocean.
20:59We did some experiments a few years ago in which we calculated the speed of breaching great whites.
21:06See how fast they were coming out of the water.
21:08And these things were heading up to 19, 20 miles an hour.
21:10Megalodon would probably have needed the same speed and power 12 million years ago.
21:20The smaller, more agile Cetothere whale, similar to the modern-day Minkey whale,
21:26would have been a fairly common prey item for Megalodon.
21:29Still, they were a tough test for Megalodon's hunting ability.
21:33Although this whale was only one-fifth the length of the adult Megalodon,
21:37it still weighed a massive 9,000 kilograms.
21:41Using its powerful tail muscles, the 15-meter carnivore rockets towards the surface.
21:48The whale may not have a higher top speed than the Megalodon, but it was more agile.
21:54With its awesome power and speed, the Megalodon had the ability to leap above the surface of the water,
22:01with a 9,000 kilogram whale still in its jaws.
22:04In a matter of moments, dinner was served.
22:08With one quick kill, Megalodon had proved that it had the strength and agility to rule the oceans of the world.
22:20Megalodon ruled the oceans for almost 20 million years.
22:25But even top predators have to keep their lineage going from generation to generation.
22:29Most scientists agree that, like the great white, the prehistoric Megalodon gave birth to live young.
22:39The Megalodon probably gave birth to only one pup at a time.
22:44When you consider that a neonate, a pup, would have been anywhere from perhaps 7 to 10 feet long, that's already a very large shark.
22:55And those baby sharks were hungry.
22:57I can see no reason why they wouldn't have been born ready to attack larger prey items.
23:04A herd of docile dugongs, or sea cows as they are sometimes called, might be just the ticket for an apex predator's first meal.
23:12One of the other kinds of marine mammals that were prey for Megalodon were the sea cows.
23:21They were dugongs, not manatees.
23:23Manatees are a more recent evolutionary arrival.
23:26So dugongs have tails very much like dolphins, unlike the manatees which have the more rounded beaver-like end of tail.
23:33The mature dugong was about 3.5 meters long, compared to the baby shark's 3-meter body.
23:40Based solely on size comparison, the baby shark would seem to be at a disadvantage.
23:47But size is only one part of the equation.
23:50They are relatively slow, sluggish animals.
23:54This is a section of sea cow rib, very heavy and dense.
23:58And you'll notice that there's this bite mark running across the rib, made by the tooth of a very large shark.
24:07The hungry baby shark rushes forward.
24:12One small juvenile dugong is slow to react, and the shark is on it.
24:17A lifetime of hunting has begun.
24:20Scientists are also keenly interested in just how long was the lifetime of these giant sharks.
24:29In the Fossil Preparation Laboratory at the Florida Museum of Natural History,
24:34Dr. Bruce McFadden and his students are doing cutting-edge research into the lifespan and eating habits of prehistoric sharks.
24:42Scientists study growth rings within the relatively few vertebrae of Megalodon that are known to exist.
24:47This is one way to discover more about these magnificent beasts and their daily life.
24:54We count them just the way somebody would count tree rings.
24:57The lower portion of a shark's vertebra is known as a centrum.
25:01In Megalodon, centra are extremely rare.
25:04Scientists are looking at the few samples they have to see what else they can learn about this prehistoric beast.
25:08Most of the samples that we have indicate that Megalodon lived somewhere between 25 and 40 years.
25:16It could have lived longer because it didn't have any predators.
25:20Estimates of how much the Megalodon needed to eat range from 600 to 1200 kilos of food a day.
25:26This high-energy animal must have been consuming a wide range of fish and marine mammals to sustain its life.
25:32We don't know exactly what foods they were feeding on.
25:38No matter what they were eating, one thing is clear.
25:41These massive sharks spent the bulk of their lifetime in a never-ending search for food.
25:45And 15 million years ago, Miocene Epoch oceans were filled with a variety of marine life from which the Megalodon could choose a meal.
25:55Whales, dolphins, dugongs, huge sea turtles and hosts of fish filled the coastal sea waters around the world.
26:03The Megalodon was probably eating them all.
26:06The most common group of whales during the Miocene was the Cetothera.
26:10These small whales ranged from 3 to 6 meters and were found in warmer coastal waters all around the world.
26:18A whale that fed on plankton, crustaceans and tiny fish, these ocean mammals were quick and agile despite their hefty 9 to 18,000 kg size.
26:29Like the Dagong, these gentle creatures were likely easy targets for the hungry Megalodon.
26:33But Dr. Stephen Godfrey has one piece of whale backbone that may demonstrate Megalodon was not always successful in its hunt for prey.
26:41Unfortunately, the surface of the bone is worn and the secret to what happened to the whale is hidden from sight inside the vertebra.
26:48So we've got it up off the table. Now do you want the entire thing scanned or just through pathology?
26:56The modern CAT scan can help. Godfrey uses today's technology to look back some 12 million years.
27:03It reveals the severity of the ancient whale's injury. A compression fracture runs the length of this vertebra.
27:09Dr. Godfrey theorizes what might have happened when the small whale was attacked by the massive Megalodon.
27:17I believe that this whale was hit by the giant Megalodon.
27:22And that intense impact caused the vertebra to experience this intolerable strain that popped the bottom of the vertebra off, pushed it forward.
27:30And the healing that went on here in this vertebra is evidence that, in spite of the intensity of the impact, it survived.
27:40It is the story of one Megalodon's missed prey opportunity and one whale's fight to get away.
27:45Perhaps this time, when the prowling Megalodon looked up at the surface of the water, there was a pod of three whales swimming by, full-grown adults, closer to six meters, and weighing in at 18,000 kilograms.
28:02The Megalodon positions itself under the whales for an ambush.
28:05The small whale wavers, and the giant shark cannot adjust its trajectory.
28:18The Megalodon's massive jaws miss their target, and his head smashes into the whale's back.
28:25As the CAT scan proves, this time the whale escaped.
28:32The whale was lucky.
28:35In most cases, it was easy prey for Megalodon.
28:39But 20 million years ago, there was another marine mammal that could match Megalodon's aggression.
28:47This is a skull of an ancient whale called a Squalodont.
28:53And these animals could echolocate, and they were probably top predators for their time.
28:58A Squalodon would have been a pretty formidable opponent.
29:00Squalodon didn't get as big as Megalodon, but they got a pretty good size.
29:0525, 30 feet, I think, would be a pretty good estimate for a reasonable size Squalodon.
29:13Squalodon was a top predator, like today's transient hawkers.
29:17If we want to interpret any behavior of an extinct animal, we have to look at modern animals.
29:20In the case of these Squalodons, we would probably look at the modern killer whale.
29:26Whales have been known to attack sharks. It's not simply a one-way street where sharks attack whales.
29:32Squalodon, at a maximum length of 9 meters, would not have taken on a 15-meter Megalodon by itself, but they would fight.
29:41If the Megalodon spotted a Squalodon, it wouldn't have hesitated to attack.
29:47Scientists believe these marine mammals may have traveled in pods.
29:52Squalodon, being a big-toothed whale, would have been a highly intelligent animal.
30:01Megalodon, not so much.
30:04Higher reasoning powers in sharks, not nearly as well developed as what we find in marine mammals.
30:10Even an enormous animal like Megalodon is going to feel this punch in the gills.
30:23This time, it's outnumbered.
30:32The first Squalodon may not survive for long, but the Megalodon has sustained a few battle scars of its own.
30:38Not all attacks were successful. Like all predators, only a certain percentage of their attacks actually result in killing a prey that they then consume.
30:49But prey species other than Squalodons and Dugongs may have provided richer pickings.
30:54There were also large whales swimming in the coastal waters of the Pliocene epoch.
30:59Really large whales.
31:01And when Megalodon wanted a three-course dinner, it may have gone after a beast even bigger than itself.
31:08The modern blue whale is a magnificent animal.
31:19Rarely photographed, and usually seen only by accident, this massive marine mammal is a startling reminder of the awesome majesty of some of the sea's most elusive creatures.
31:29Five million years ago, the whales Megalodon encountered may have been almost as impressive.
31:35Here I'm just thinking about what modern things like fin whales and blue whales look like.
31:40It would have been a coastal animal. It would have been a migratory animal.
31:43It probably was gray with a lighter shade below. We usually estimate the weights of living baleen whales at about a ton of foot.
31:53So if you have an animal 75 to 80 feet long, it would be about 75 to 80 tons.
31:56So you've got at least five species there. You know, those actually look like herpetocetins, the weird kind of suit of theirs.
32:06Dr. Lawrence Barnes and his colleagues have uncovered hundreds of whale bones in the last few decades.
32:10One intriguing discovery was a large whale found near Santa Barbara with a shark tooth tip stuck in its jawbone.
32:19Here was a creature that was possibly three to nine meters longer than Megalodon, a whale that would have outweighed the shark by 22,000 kilograms.
32:30But the reward for killing a larger whale would have been a much bigger food source for the Megalodon.
32:35A whale of this size is packed with layers of tough, stringy blubber.
32:42Megalodon would need all of the size volume and deadly serrations along its teeth to take down the animal.
32:49The key this time is bite force. How much jaw power did Megalodon actually have?
32:54At the University of New South Wales in Australia, Dr. Stephen Rowe is using high-tech computer sleuthing
33:01to try and understand the cranial mechanics of bite force found in modern and prehistoric animals.
33:10Bite force is the amount of pressure applied when the jaws of an animal bite down on its prey.
33:16What's generating the bite force here are the actual jaw-closing muscles.
33:21What we're looking at is a simple lever system.
33:23So we apply force on one end of the lever and we get a reaction force on the other end of the lever.
33:33Rowe's process for understanding bite force in sharks starts with the gruesome task of cat scanning a shark head at a local hospital.
33:40I then build a surface model and from that I can then create a solid three-dimensional engineering model or finite element model.
33:54From this engineering model, Rowe has figured out the potential maximum bite force of the modern great white shark.
34:00In the case of a really big white pointer, we're predicting a bite force around about 4,000 pounds.
34:09These largest of white pointers are really pushing the envelope as far as living animals are concerned.
34:15With the bite force per inch data from the great white, Rowe extrapolates what he believes to be a fairly accurate understanding of the bite force of the megalodon shark.
34:24Toward the upper end of estimates of body mass for megalodon, we're getting bite force estimates of about 40,000 pounds, which is just humongous.
34:37With 40,000 pounds of bite force, you could bite through a truck if you had the teeth and jaws to stand up to it.
34:43This must have been an absolutely terrifying object to any way.
34:47Of course, living large baleen whales get very, very anxious when they see or hear orcas or killer whales.
34:56But the sight of one of these guys coming at them must have been just absolutely horrific.
35:01The baleen whale didn't have much time to be anxious once the attack had begun.
35:05It would appear that megalodon typically took out large whales by swimming up behind them, biting their tail flippers off, basically just disabling the whale's propulsion system altogether.
35:19This is certain death for the whale as he bleeds out through a gaping hole in his artery.
35:34But with no hands to hold down his enormous prey, how did the megalodon keep the 68,000 kilogram whale from swimming off after one bite to the belly or throat?
35:45At Wright State University in Ohio, paleontologist Chuck Ciampaglio has constructed an experiment that demonstrates the deadly potential of the megalodon to attack a giant prey item.
36:00A high-density gel mold will simulate whale flesh.
36:05The centerpiece of the demonstration is a set of mechanical megalodon jaws that he believes simulates the unique jaw motion of the shark's mouth.
36:13These jaws are really interesting because in addition to being able to lift up and down, they also are highly mobile in a forward direction just like modern laminids and megalodon would have been also.
36:28The metal jaws are firmly attached to the table and instead of having the jaw attack the mold, the bite is replicated by having the mold rolled into place inside the mouth.
36:37The shark uses its lower teeth to initiate the attack and hold its prey in place.
36:42We can see the lower teeth anchored into the flesh a good three inches. It's already starting to tear the flesh. This is holding down the flesh and now the top is going to make its bite.
36:55The upper jaw bites down on the prey with its powerful serrated teeth.
37:02At that point, megalodon would thrust back and forth until a bite was made.
37:07The bottom jaw continues to anchor into the gel flesh while the unique upper jaw, with its ability to move somewhat independently from the rest of the skull, takes bite after bite, pulling flesh into its mouth as it continues to feed.
37:23OK. What we've created are massive wounds to our prey item. We can see that the teeth have made huge gouge marks, have split off nearly half of the flesh.
37:36Now, if this was the actual shark, this piece of flesh would extend out in both directions, probably three or four feet because of the size of the jaws.
37:45And you would have probably nearly 40 teeth sinking into the flesh.
37:51The mechanical jaws leave no doubt about the powerful combination of bite force and cutting power that megalodon used on prey like the Santa Barbara whale.
38:00Within minutes, the whale is nothing but a tasty carcass floating south along the California coast.
38:07For one more day, megalodon has found a meal, a very big meal.
38:11But unfortunately for megalodon, during the Pliocene epoch, ocean temperatures started to cool.
38:18The numbers of whale species were also diminishing.
38:21Megalodon's reign as the all-time apex predator of the sea could be nearing its end.
38:30Megalodon disappeared from the fossil record during the Pleistocene epoch, around 1.8 million years ago.
38:36Scientists are unsure why this efficient hunting machine's time at the top of the predator list came to a close.
38:45Extinction is always something that fascinates people.
38:49We want to know not only how things live, we want to know why they died, why they're no longer around, why they're no longer with us.
38:54The assumption there, though, is always that extinction is somehow the fault of the animal or the species that goes extinct.
39:02It's because it was poorly adapted or a negative thing.
39:05That's not necessarily always the case.
39:07Clearly, species want to perpetuate their existence.
39:09Paleontologists are unsure what finally killed off the shark.
39:15Could another apex predator, like the killer whale, have wiped out the megalodon?
39:20Another intriguing possibility is changes in climate.
39:25Six to 1.8 million years ago, just as megalodon teeth disappeared from the fossil record,
39:31scientists have noticed a cooling in the ocean temperatures.
39:33This may have adversely affected a shark accustomed to swimming in warmer waters.
39:46Paleontologists also know that as the Miocene epoch progressed, the population of smaller whales was replaced by larger whales.
39:54These whales may have favored colder climates to the north.
39:57It might very well be that as whales became migratory and spent the summer time in northern latitudes,
40:05that in fact the sharks just didn't have access to the big whales.
40:11By the middle of the Pliocene, without year-round access to larger prey,
40:17megalodon may have been feeling acute hunger pangs.
40:19With a loss of a large portion of the whales, perhaps three-quarters of all the whale species at the time,
40:26we ended up losing a major food source for megalodon.
40:30The giant shark would have become increasingly desperate for food.
40:35Cannibalism was always a possibility with megalodon, but could have increased as other sources of food thinned.
40:41Smaller megalodon teeth have been found in deposits alongside other marine mammals that were prey items for the shark.
40:50There is speculation that these juvenile megalodons may have been at risk from bigger, hungrier megs.
40:56The closing of the land bridge in South America may have also affected the worldwide migratory patterns of some marine animals.
41:06The disappearance of the Central American seaway, and its replacement by land bridge,
41:11and the effect upon marine organisms has been debated among scientists.
41:16When we look at things like even the modern sperm whales, the same species exist in both the Atlantic and Pacific.
41:21And the question is, are they going around the southern continents, or are they just very slow to evolve?
41:28It is unclear if the closing of the isthmus of Panama that connects North and South America could have affected megalodon.
41:36Scientists continue to search for clues about megalodon and its demise by studying the great white shark.
41:43For starters, the modern great white is equipped with a remarkable internal heating system known as gigantothermy, which is an excellent survival tool.
41:54Most fish are cold blooded, and the great white isn't. It's warm blooded.
41:59It elevates its body temperature up above the ambient water temperature, which for a long time was a characteristic solely assigned to mammals.
42:07And they do that with a special system of blood vessels that actually warms the blood that supplies critical parts of the shark's sensory biology,
42:17so the eyes, the nose particularly.
42:20Paleontologists have not yet figured out if megalodon possessed this extraordinary biological capability.
42:26If they did not, as temperatures cooled, it's possible the great white was in a better position to withstand the dip in the ocean temperatures.
42:34More importantly, scientists believe having more variety in its diet probably helped the great white shark.
42:43While megalodon was primarily preying on larger marine mammals, the great white was able to eat smaller prey items and fish.
42:50They need less biomass to keep going.
42:54They're probably not as much pressure, if you will, as there is on an apex predator the size of megalodon, which would need a tremendous amount of biomass to maintain its existence.
43:05In essence, unlike the great white, megalodon may well have eaten its way out of existence.
43:12The great white was clearly a more adaptable animal, and as a result it flourishes in oceans around the world to this day.
43:22But the question of whether these two magnificent sharks were related continues to interest scientists.
43:28Paleontologist Chuck Ciampaglio and other experts insist there was little direct relationship between megalodon and the great white.
43:38According to Ciampaglia, advanced computer technology underscores the differences between the two animals.
43:44I think one of the things I'd like to see cleared up is to allow megalodon to be called, you know, Carcharocles megalodon, change the name, separate it out from the great white, and let's get on with business at this point.
43:58The great white tooth and the megalodon tooth do have some markings in common, both are triangular and serrated.
44:04But the great white tooth and its prehistoric ancestor have little or no scar at the base, whereas the megalodon clearly has a prominent chevron-shaped scar.
44:14And blowing up the great white tooth to the same height of a megalodon tooth reveals that even at the same length, the great white fossil tooth is noticeably thinner and more gracile than the megalodon tooth.
44:26Well, let me, let me do the converse here. Let me show you a very small megalodon, about approximately the same size as this great white, and you can see that small sizes the megalodon doesn't look the same.
44:38Again, the serration densities are different. This tooth is distinct from this great white no matter how big you make it.
44:45The team compared the dentition of the modern great white, the extinct mako, and megalodon.
44:50And what we found consistently was whether or not we looked at the root, the blade, or the entire tooth, was that the extinct mako and great white always clustered together for every tooth position, while megalodon always clustered away.
45:05Megalodon and the great white are not directly related. Megalodon is not the extinct great white, and all scientific evidence points to this.
45:12Or does it? Looking all the way back to the first jaw recreation in 1909, there are scientists who still insist the great white shark is more directly related to the megalodon.
45:25The smoking gun? Rare fossilized megalodon vertebrae.
45:29Backbone anatomy suggests that megalodon and great whites are quite closely related to one another.
45:35These researchers are turning to work being done on the centra of megalodon vertebrae to support this theory.
45:40I think because the vertebral centra haven't been as thoroughly studied, they provide some very important clues, and I think they ought to be studied very carefully.
45:50But megalodon centra are not common.
45:53Worldwide, for the 16 or 17 million years that it lived, we probably have on the order of a dozen to two dozen vertebral centra of megalodon preserved.
46:05It will be some time before scientists can collect more comprehensive data in this area.
46:12Perhaps the information locked inside the vertebral centra can finally answer the question of whether or not megalodon's legacy lives on in the great white shark.
46:20One point everyone agrees on is that there is much more to learn about the physical makeup and behavior of megalodon.
46:29And one thing is certain. The unique combination of physical size, tooth shape, jaw strength and appetite created an animal unique in the 400 million year history of sharks.
46:40Big tooth is still the all time king of the sea.
46:47Big tooth is still the all time king of the sea.
46:48Big tooth is still the all time king of the sea.
46:50Clock from the sea, Christopher Syduker
46:55and Peter, after
47:00Big tooth inner
47:04One thing is one thing
47:06tower to protect hair
47:08One of the sharppect behaviors
47:10Four of the sea
47:12One thing of the
47:15To protect
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