Uncovering The Megalodon's Mysterious Extinction

I haven't told you yet, but my name is John Titor, paleontologist by profession and occasional time traveler. Those who follow this scientific channel will no doubt remember the video of my adventure into the Cretaceous on the trail of the last Tyrannosaurus. Timing Inc., the company that offered me the opportunity to time travel, had arranged for me to find a tree platform from which to safely monitor the comings and goings of dinosaurs all around, plus enough food to last at least a week, and top-notch technological equipment, including binoculars, cameras, and a couple of very useful drones. That was a month ago. Now my camp has been set up on one of the many islets from which today's Florida was formed. And I'm in the Miocene, an epoch that Time Inc. assures me dates back 9 million years. And if the first time I had risked my life to become the first human being to have seen a Tyrannosaurus up close, now I'm here to investigate the most monstrous creature that has ever inhabited Miocene waters, the Megalodon. Have you ever heard of it? Of extinct animals that tickle our fancy, there are indeed many, but if we exclude the dinosaur rulers of the Mesozoic, few can rival and empower the mythical Megalodon. Due to an avalanche of B-movies depicting them unfairly as bloodthirsty killing machines, sharks have become, for the general public, the worst nightmare of the deep sea. Imagine then the effect of knowing that 3 million years ago, there roamed the oceans a shark big enough to swallow whales as if they were meat rolls. In the collective imagination, the Megalodon has in fact become the perfect marine predator, a version on steroids of the already deadly great white shark. But how much truth is there in these reconstructions? Let's find out, as I scramble to get settled in this tropical paradise, who this legendary animal was and, more importantly, when and why it became extinct. The Megalodon lived between the Miocene and the Pliocene roughly between 23 and 3.6 million years ago. Its name means big tooth, because it is largely due to the somewhat worldwide discovery of its oversized teeth and a few vertebrae that we now know of its past existence. As with other sharks, the Megalodon's skeleton consisted almost exclusively of cartilage, a tissue that very rarely manages to fossilise and be preserved over time. The vertebrae, and especially its huge teeth, are therefore the only body parts we know of and have been able to find in large quantities in the rocks. Therefore, all the hypothetical living reconstructions and size estimates are based on these remains and comparisons with other fossil and currently living species. Because of the limited information extrapolated from the fossils, we, therefore, do not know for sure what it really looked like, let alone how big it was. Actually, there's even strong debate in the scientific community about what scientific name to give it and in which shark family to place it. Because of the resemblance of its serrated teeth to those of the white shark, it was immediately thought to belong to the same family and genus. But recent studies tend to place the Megalodon in a family of sharks now completely extinct. Nevertheless, the Megalodon is still depicted today as a giant version of the white shark, which was already present at the time of the Megalodon, but its appearance was almost certainly very different. Megalodon probably possessed a much shorter snout and flatter jaw, and because of its large size, it must also have had longer pectoral and caudal fins, which facilitated its movement in the water. Overall, today we imagine it to be far more similar to the largest currently living sharks, such as the whale shark or basking shark. And this is precisely what brought me here. It would be quite a coup for paleontology and for my career to be able to find one of these creatures and test all the hypotheses about its true appearance. But finding a Megalodon is not as easy as meeting a Tyrannosaurus. The big fish just sits in the water while I sit on the beach of this tiny island, and for no reason in the world would I trust myself to go looking for it in its element. In fact, I never come within 20 meters of the shoreline, having seen too many documentaries about forays that killer whales make to catch seals sunbathing blissfully on the beach. What are my chances then of getting to see one? Unfortunately, very little. But I am very confident in the help that the two underwater drones that I have brought with me will be able to give me, and especially in the effectiveness of a paste that, according to the chemists at my university, is supposed to attract all the sharks around here. Paste that right now, as I continue talking to you, I am beginning to shoot with a jet pump up to a hundred meters away from the beach. Okay, but now you may be wondering just how big was this Leviathan? As I have already told you, all estimates of length and weight are based on the size of the teeth, which could reach the impressive length of up to 18 centimeters. The maximum size of a white shark, on the other hand, comes to about 5.5 centimeters. Until a few years ago, abnormal measurements had been speculated, even reaching over 25 meters in length. However, these dimensions have recently been adjusted downward. More accurate studies and calculations, in fact, believe more likely that the adult megalodons were about 18 meters long, which is still about three times the length of a large white shark and weighed between 25 and 50 tons. A predator of this magnitude undoubtedly had few rivals and was able to catch equally giant prey, as evidenced by the marks of its teeth found on several fossil remains of whales and other cetaceans. In fact, the fossils suggest that his favorite prey were indeed dolphins, small whales and sperm whales, which they probably attacked using different hunting techniques as appropriate, somewhat even like white sharks do today. And another question is this. If it was so mean, big and dominant, why would it have become extinct? We know from the fossil remains that the megalodon disappeared from circulation toward the end of the Pliocene, about 3.6 million years ago. We do not know exactly what was the cause of its extinction, but right around that time the Earth faced a severe cooling period that may have played a key role. As fossil remains show, megalodons lived in waters all over the world, but they especially preferred tropical belts and warm waters, where it was easier to large prey. The drastic drop in temperatures that affected the oceans almost certainly not only directly harmed sharks, but also reduced the number and availability of large prey, causing a series of chain reactions that disrupted ecosystems. Surviving cetaceans began to adapt to colder waters, where the megalodon could not reach them, and new forms of large predators, such as killer whales and other odontocete cetaceans, began to take over. It was thus most likely a mix of climate and environmental changes, poor availability, and competition with larger cetaceans that sealed the final extinction of the megalodon. Well, while I was telling you these things, I continued to shoot a bunch of that infernal mixture into the sea here up ahead. And now all I have to do is unleash my drones, both aerial and submarine drones. I know you're also curious about my surroundings, but I fear I must disappoint you. Everything here is almost indistinguishable from any Caribbean beach of your time. My island, for that matter, is too small to harbor any wildlife worth mentioning. I see endless colonies of seabirds, inland an impressive number of snakes, and nothing more. I do know, though, that 30 kilometers from here, on the North American continent, rhinos and hippos roam, as do the ancestors of saber-toothed tigers, and that somewhere in East Africa, a small number of primates are desperately trying to survive to start our own species. And it's kind of impressive to think that. But there goes drone one. The sea is calm, the water transparent, and by flying over its surface, the small craft should be able to spot the dark silhouette of a megalodon, if there is one. It is still morning, and I still have all afternoon to be able to see something, and then a whole week too. I feel pretty confident. But could the megalodon still exist today? A popular idea is that megalodon might be hiding in a small population somewhere in the ocean's depths that we have not yet explored, just like the megamouth shark discovered in 1976 and the famous coelacanth found in 1939. There's one key difference, however. We know for a fact that the megalodon was a huge predator that needed to eat more than a ton of meat a day to survive, an amount of food it certainly could not find in the uninhabited ocean depths. But wait a minute, drone one is showing me some movement 200 meters away. Below the surface dot dozens of dark shadows. Perhaps a large part of centriodon, an ancestor of our dolphins, very common in North America at this time. Are they chasing or being chased? I bring the drone up in altitude to widen the field, and something huge pops up on the edge of the frame. A black silhouette gliding slowly in the direction of the fleeing dolphins. Is it a megalodon? I wouldn't swear to it, but no other predator of this size would venture into such shallow water. I'll call off the flying drone and place the submergeable one in the water. And in doing this, I realize with horror I have entered the water up to half my body. I start the drone and rush back to the station. On the monitor, the crystal clear water allows me to push my gaze for meters in every direction. I attempt to bring the drone up to the spot where I spotted the centriodon. And lo and behold, bam! The drone almost gets run over and flipped over by a huge beast. It is indeed a megalodon, what else could it be? I rearrange the drone and launch it in pursuit, what I was then able to capture on this amazing day you are also seeing. The resemblance to our white sharks is striking, but there's something primitive and primordial about this beast that we are seeing in full hunting action, something I can't quite grasp. A pity it's getting dark, the silhouettes are becoming indistinct, but I still have six days to go. Think of me, for I'm very lonely here.