C. megalodon is thought to have grown to approximately 60 feet long, and to have gone extinct around 2.6 million years ago. However, not everyone is convinced that megalodon is dead and gone. Some megalodon truthers think the massive shark is alive and well and living undiscovered in the Earth's oceans—and they often point to the sightings described below as evidence. 

Even if you believe that megalodon is long extinct (in which case, you're in good hands; scientists everywhere agree with you!), the myth of the modern megalodon is still fascinating. If nothing else, these alleged sightings prove humans are fascinated by the ocean's mysterious depths. And in an ideal world, that fascination might lead to increased interest in conservation of actual extant sharks. 

This first entry isn't a sighting, but a fossil find that's sometimes brought up and frequently misinterpreted in discussions of whether or not megalodon is still with us. 

In 1875, the British ship HMS Challenger pulled up a pair of megalodon teeth from a seabed. In 1959, Dr. W. Tschernezky of London’s Queen Mary College attempted to date the teeth by studying the buildup of the manganese dioxide layer on each tooth. Through examining manganese dioxide deposition, Tschernezky determined the teeth were 11,000 and 24,000 years old, respectively. If correct, those findings would indicate that at the very least, megs may have gone extinct far later than previously thought. 

However, manganese dioxide dating is often unreliable, particularly in dating shark teeth. As Ben S. Roesch writes in the 1998 Cryptozoology Review article "A Critical Evaluation of the Supposed Contemporary Existence of Carcharodon megalodon,"

"Researchers now believe that this and all other claims of post-Pliocene C. megalodon teeth (some of which are more convincing than Tschernezky’s work) are erroneous, representing reworked material from older deposits [...] Whereas reworked fossil bones often show wear from the process, shark teeth (and vertebrate teeth in general) are very durable structures that can withstand high pressures, erosive forces and long-distance transport. Their durability makes it difficult to determine if they have been reworked from older deposits."

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In his book Sharks and Rays of the Australian Seas, Australian naturalist David Stead shared this anecdote, which some believe describes a terrifying encounter with Meg herself:

"In the year 1918 I recorded the sensation that had been caused among the "outside" crayfish men at Port Stephens, when, for several days, they refused to go to sea to their regular fishing grounds in the vicinity of Broughton Island. The men had been at work on the fishing grounds—which lie in deep water—when an immense shark of almost unbelievable proportions put in an appearance, lifting pot after pot containing many crayfishes, and taking, as the men said, "pots, mooring lines and all". These crayfish pots, it should be mentioned, were about 3 feet 6 inches [1.06 m] in diameter and frequently contained from two to three dozen good-sized crayfish each weighing several pounds. The men were all unanimous that this shark was something the like of which they had never dreamed of. In company with the local Fisheries Inspector I questioned many of the men very closely and they all agreed as to the gigantic stature of the beast. But the lengths they gave were, on the whole, absurd. I mention them, however, as a indication of the state of mind which this unusual giant had thrown them into. And bear in mind that these were men who were used to the sea and all sorts of weather, and all sorts of sharks as well. "

"One of the crew said the shark was "300 feet [90 m] long at least"! Others said it was as long as the wharf on which we stood—about 115 feet [35 m]! They affirmed that the water "boiled" over a large space when the fish swam past. They were all familiar with whales, which they had often seen passing at sea, but this was a vast shark. They had seen its terrible head which was "at least as long as the roof on the wharf shed at Nelson's Bay." Impossible, of course! But these were prosaic and rather stolid men, not given to 'fish stories' nor even to talking about their catches. Further, they knew that the person they were talking to (myself) had heard all the fish stories years before! One of the things that impressed me was that they all agreed as to the ghostly whitish color of the vast fish. The local Fisheries Inspector of the time, Mr Paton, agreed with me that it must have been something really gigantic to put these experienced men into such a state of fear and panic."

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Of course, this account is anecdotal, and even if the shark observed by the fisherman was as massive as this account describes, several signs indicate that it couldn't have been mighty Meg. As Roesch writes in his 1998 paper,

"Worth noting in reference to the colour of the 1918 alleged shark is that while some researchers have suggested that the resurrected C. megalodon might live in the deep-sea [...] deep-sea sharks certainly are not white—in fact most are uniformly dark, both on the dorsal and ventral surfaces of their bodies. (I mention this because I can imagine that some supporters of C. megalodon survival might suggest that the whitish colour of the 1918 alleged shark could be an adaptation to the virtually lightless deep-sea. It seems instilled in the minds of many that a dark environment results in white animals. While this is the case in many cave animals and a few deep-sea creatures, lack of pigmentation is certainly not a general feature of deep-sea animals)."

In his 1978 book Let's Go Fossil Shark Tooth Hunting, author B.C. Cartmell describes an alleged incident that took place off the edge of Australia's Great Barrier Reef in the 1960s:

"An 85-foot ship experienced engine trouble, which forced it to weigh anchor for repairs. Although the men subsequently refused to openly report what they had seen for fear of public ridicule, the captain and his crew later told friends of sighting an immense shark as it moved slowly past their ship. Whitish in color, they were awed by its size. It was as long, if not longer, than their boat! Experienced men of the sea, they too were certain the creature was not a whale."  

Was it the megster? Probably not—but whatever the sailors saw that day, it's proof that the ocean is a fascinating place. 

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The Black Demon of Cortez is believed to be a massive, black shark seen off Mexico's Baja Coast. Some reports allege that the big boy may even be comparable in size to the ancient megalodon. In one alleged encounter, fisherman Eric Mack reported that the Black Demon rocked his boat, while its towering tail stuck five feet out of the water. Of course, if the 'Black Demon' is real, that doesn't mean it's a megalodon—it could easily be a plankton-eating whale shark or even a large great white with melanism. 

The enormous black shark was the focus of an episode of the History channel cryptozoology TV show Monsterquest. However, the investigators failed to find any evidence of the fabled 'demon.'

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Novelist and deep-sea angler Zane Grey claimed to have had an experience with a massive shark that some believe could have been a megalodon. In the novel Megalodon: Fact or Fiction?, Rick Emmer writes that Grey claimed to have seen "one of the man-eating monsters of the South Pacific," a shark much longer than his 30-40 foot boat. Apparently, the shark was "yellow and green ... (with a) square head, immense pectoral fins and a few white spots." In other words, not a mere "harmless white shark."

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As fun as it is to imagine these stories are evidence that megalodon is still alive, that's just not the case. As Meghan Balk, a megalodon researcher at the University of New Mexico, told The Daily Beast: “there is no doubt in the scientific community that Megalodon is extinct.” 

Balk explains that megalodons stayed close to the coast, so if they were still alive today, we'd know—it would be hard to miss a 50-plus-foot super predator roaming the shores! According to Balk, "Megalodon fossils appear in shallower marine sediments. Plus, most large sharks occur in the upper 500 meters of the water column, probably due to productivity. The deep is much too nutrient poor to support such a large animal." 

In many ways, Shark Week is responsible for popularizing the myth that megalodon is still around. In 2014, Discovery aired the highly controversial Shark Week 'mockumentary' ''Megalodon: The Monster Shark Lives.'' The incredibly misleading program presented 'evidence' that megalodon was not only still alive, but also attacking humans and boats. Although a brief disclaimer at the end of "The Monster Shark Lives" explained that it was a work of fiction, many viewers were understandably fooled by the 'eyewitness accounts' and interviews with 'scientists.' The next year, Discovery aired a follow-up mockumentary called "Megalodon: The New Evidence," which only compounded the confusion.

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Sadly, even if megalodon were discovered to be alive today, experts say it's likely humans would soon put them on the path to extinction again. Conservationist, shark expert, and Shark Week critic David Shiffman wrote in 2014 that megalodon would probably be hunted for its fins:

"Let’s ignore recent market trends and the extra added value of rare, large fins, and just the low-end estimate of $400 per kilogram. If a typical adult megalodon has 1.5 metric tons (1,500 kilograms) of fins, and fins sell for $400 a kilogram, then the fins of an adult megalodon could be sold for a total of $600,000. If it takes three quarters of an ounce of dried shark fin to make one bowl of shark fin soup, then with 1.5 metric tons (52,910 ounces) of shark fins, you could make 70,456 bowls of shark fin soup."

And, as Shiffman points out, "if the hypothetical overfishing of a species that has been extinct for millions of years has you as upset as it has me, you should learn more about the real overfishing of shark species that are still around… at least for now."

(via Exemplore; Seeker ; Mysterious Universe ; IFLScience ;Scientific American)

Featured still from the cover of "Meg" by Steve Alten