A megalodon is an ancient and extinct species of shark, believed to be the largest predator in the oceans during its reign, which lasted for roughly 20 million years, before these massive sharks went extinct about 3.5 million years ago.
If you’ve never heard of a megalodon before, then you clearly haven’t been keeping up with Hollywood’s 2018 blockbuster The Meg, a terrifying sci-fi film featuring a massive shark about the size of two 18-wheelers! While the size may have been slightly exaggerated to make some movie magic, that beast in the movie is based on a real creature, an ancient species of shark that some people believe may still be lurking in the depths of the ocean to this day.
Between amateur documentaries and the overblown hype of Hollywood, there has recently been a lot of confusion about this creature—did it ever really exist? Why did it go extinct? Could the species still be alive today? Let’s try to clear up some of this mystery!
What is a Megalodon?
To begin with, megalodon is the informal name for this shark species, which is scientifically known as Otodus megalodon, although it was once believed to be closely related to great white sharks (Carcharodon carcharias). As it turns out, megalodons far surpassed great whites in terms of size, growing up to 18 meters (60 feet) in length—roughly 3 times as long as a female great white.
Our best estimates are that these huge sharks roamed the oceans from about 23 mya to 3.6 mya before they suddenly went extinct, despite being the largest predator on the planet.
Like many other shark species, the majority of a megalodon’s body was composed of cartilage, which breaks down and doesn’t fossilize, but we have learned a great deal from their teeth, which are made from dentin—a substance even harder and denser than bone! In rare cases, other parts of megalodons have been fossilized and preserved, including vertebrae larger than dinner plates.
Despite a distinct lack of fossilized material, the teeth that have been found can tell quite a story.
Through reconstruction and comparisons to other related species’ skeletal structure, it is believed that megalodons possessed 276 serrated teeth that were continually replaced throughout its life, and a jaw diameter of up to 7 feet! Based on a jaw that large, experts can estimate the overall size, weight and predatory habits of this oversized fish.
Though there remains some contention about the details of this monster shark, the general size estimate for adult females is about 50-100 tons, making them half as massive as a blue whale—the largest creature to ever live on Earth. Just like blue whales, it is believed that megalodons were intercontinental species, meaning that they were found in all the world’s oceans.
Unlike blue whales, however, these sharks were apex predators, with appetites that matched their incredible size.
Also, with large pectoral fins and a powerful tail, experts from the Zoology Society of London believe a megalodon could have moved up to five meters per second, based on extrapolating their metabolic potential, oxygen requirements, and size. It is estimated that these sharks could also eat over one ton of food per day, and with jaws and teeth that large, they could basically hunt anything in the oceans—and they did.
Their diet likely consisted of whales and other large types of prey, which were necessary to satisfy their gargantuan appetite. The tips of megalodon teeth have been found in the fossilized bones of whales, as well as large bite patterns that have further helped experts estimate the size of these marine beasts. Seals and sea turtles may have also been part of their diet, while the 20-foot juveniles, bred in tropical waters, likely fed on fish and small whales before reaching their adult size. While there were no natural predators for these fast-moving and well-equipped hunters, there was competition from other ancient shark species, which may have contributed to the decline in megalodons as the population balance shifted and climatic conditions changed.
Why Did Megalodons Go Extinct?
There are a number of factors that could have led to the megalodon’s eventual extinction approximately 3 million years ago.
As mentioned above, a gradual increase in predator populations—such as the ancient predecessors to great white sharks, as well as ancestral killer whales and aggressive sperm whales—could have made it harder for megalodon’s to find sufficient food, causing their numbers to drop on a global scale.
However, most experts agree that it is closely related to the cooling of the planet, which occurred at the end of the Pliocene Era, roughly 2.5 million years ago. As the planet entered a time of cooler climates, it would have drastically affected the foundation of the marine food chain, which would in turn affect all predators higher up that food chain.
The fossil record shows that between 30-40% of all large marine animals went extinct around this time, and it’s likely that megalodons simply couldn’t survive. Some of the typical prey of these huge sharks may have adapted faster to cooler waters; blubber-clad whales could descend deeper, or further towards the poles, beyond the reach of the temperate water-loving super-shark. Finally, a global cooling would have resulted in a drop in ocean levels and a cooling of shallow tropical nurseries, where the megalodons are believed to have bred and raised their young.
Could Megalodons Still Be Alive Today?
Although Hollywood would love us to believe that there is a Greyhound bus-sized killer in the deep, scientists around the world are agreed that megalodons are quite extinct, and likely to remain that way. The factors that led to its extinction lasted for hundreds of thousands of years, so the idea that any individuals persisted through these eons of untenable conditions is simply ridiculous.
Additionally, the fossils and teeth that have been found stop very noticeably around 2.6 million years ago; these sharks likely went through thousands of teeth over the course of their lifetime, yet no “new” teeth have been found from these supposed survivors. Their preference for warmer waters would mean that they remain closer to the surface, which would make them much easier to spot with 21st century technology, imaging and radar equipment.
Finally, their massive appetites would still need to be satisfied, so humans would have found recent remains (either washed up on beaches or on the ocean floor) with indicative bite marks, but no discoveries like this have taken place. Despite what circumstantial evidence and tabloid-level gossip The Discovery Channel peddles as “proof” of the megalodon’s continued existence, these massive sharks have gone the way of the dinosaurs.
A Final Word
While there are still occasional “sightings” of sea monsters around the world, the only place you’ll be able to see a megalodon swimming at you is on a movie screen! However, putting the sheer size and power of these ancient creatures into perspective is a fascinating study of the past—so long as it doesn’t give you nightmares!
- Biology letters Journal
- National Institutes of Health
- Paleobiology Journal
- PLoS One Journal
- Palaeogeography, Palaeoclimatology, Palaeoecology Journal
- Journal of Biogeography