The megalodon shark (C. megalodon) is widely regarded as both the largest shark to have ever lived on Earth and one of the largest vertebrate predators in history. Megalodons roamed the seas from around 28 million years ago until ~1.6 million years ago, when they were wiped out during the Pleistocene extinction.
Megalodons were, as we know, freaking huge. Some of the teeth discovered from this whopping great predator have been over 17 centimeters (7 inches) in total height, but the majority are between 3 and 5 inches (still, massive). Reconstructions using jaws and other fossilized remains suggest that megalodons probably reached maximum lengths of up to 54 feet (16.5 meters), around 3 times larger than great whites (C. carcharias). They even make T-rex’s look like pansies in comparison.
Image credit: Matt Martyniuk, via Wikimedia Commons.
The widespread distribution of megalodon fossils, in particular teeth, suggests that it was a cosmopolitan species that inhabited a wide range of marine environments, preferring warm and temperate shallower waters. They were at the top of the food chain and would have eaten large prey such as cetaceans (dolphins and whales).
As mentioned, megalodons went extinct an estimated 1.6 million years ago. But some people are not satisfied with this and are convinced that they might still exist. Unfortunately, some documentaries (that used fake footage) have many people completely convinced that they're still hiding in the ocean. So let’s go through the common arguments and hopefully we can reach a sensible conclusion.
First off, nobody has direct evidence to suggest that they do still exist. No, absence of evidence is not evidence of absence- we know this. It’s very difficult to prove something doesn’t exist, but equally that doesn’t mean that megalodons are still lurking around somewhere.
There have been numerous eyewitness accounts of huge sharks throughout history and also various illustrations of gigantic washed up sharks, even some photographs. One photograph in particular which stirred up a lot of controversy was an image that was presented in a Discovery Channel documentary (which was fictional) showing the dorsal and caudal (tail) fins of a shark next to a submarine, spanning a whopping 64 foot. The image was fabricated. The documentary was in fact a "mockumentary", which was stated in a very small disclaimer at the end. Plus, 64 foot (almost 20 meters) is larger than the estimates of the entire body size of megalodons! This was only dorsal fin to tail! The “scientists” that appeared in this documentary, entitled “Megalodon- The Monster Shark Lives,” were also actors. Sorry.
Sketches of huge sharks that washed up on beaches many years ago were also most likely either exaggerated great whites or basking sharks. Who knows for sure, but you can’t rely on a drawing as evidence, that’s not how science works. Eyewitness accounts are also extremely unreliable, particularly when dealing with rotting or decomposing animals. To the untrained eye, a whale shark or a basking shark could look like some kind of giant great white. It’s an easy mistake to make.
A couple of unexpected discoveries have also fuelled belief that megalodons still exist; coelacanths and the megamouth shark. Coelacanths are an extremely old species of fish that were thought to have been extinct since the end of the cretaceous period, around 65 million years ago. However, much to the excitement of the scientific community, one was caught in 1938 and another in 1952. Since then many have been spotted throughout the world. The coelocanth is a fairly easy species to miss - they typically live at great depths, and spend much of their time in caves. Just because we were wrong about coelacanths, it doesn’t mean that megalodons exist.
The megamouth shark was discovered only in 1976. This shark is a plankton feeder that can reach up to 15 feet (4.5 meters) in length, so it’s pretty big. Yes, this does highlight the fact that even relatively big shark species can escape our radar and spend years lurking in the oceans unnoticed, but once again that doesn’t prove that megalodons exist. The megamouth is a plankton feeder, and swims at great depths during the day, making its detection difficult.
Sharks also regularly shed teeth, but we haven’t discovered any megalodon teeth that indicate they were recently lost.
Another idea that sometimes crops up - could megalodon be hiding in really deep oceans, escaping our detection? Probably not. Fossil evidence from megalodons suggests that they preferred shallower, warmer waters and would have inhabited areas rife with large prey needed to sustain their populations. They also used coastal areas as nursing grounds. Furthermore, it’s thought one of the factors that may have contributed to their extinction was the migration of their prey to colder waters, restricting the prey available to them. They just were not adapted to life deep in the oceans (we’re talking really deep here for something this ginormous to be able to escape detection).
So, we’ve only explored a tiny portion of our oceans. This is true. But the VAST majority of ocean life lives in the first few hundred meters, where the sunlight can reach. Below that, life becomes highly specialized and large animals are rare. Megalodons were HUGE and would need a constant supply of large animals to feed off. Maybe megalodons didn't go extinct but evolved into a smaller, specialized shark capable of living deep in the oceans? Well then that wouldn't be a megalodon anymore.
Even if they were, somehow, hiding in deep oceans like the giant squid - we still have documented evidence of the giant squid! Tentacles and bodies have been washing up for years, and footage of live animals has been shot over the last couple of years. I reiterate- megalodons were HUGE! If they still existed, we would know about it. They would be chowing down on massive sharks and whales all over the world. We would see bite marks on whales, scars from old attacks too large to be from any known shark. It would be a spectacular sight, but unfortunately not one that we are going to see.
We’re sure most people are happy with the idea that megalodons are extinct, but for the few individuals that are still hopeful they exist- we hope this is enough to convince you that science says no.
Just sitting in one's jaw, as one does. Image credit: Reconstruction by Bashford Dean in 1909, via Wikimedia Commons.