The megalodon, which went extinct millions of years ago, was the largest shark ever to prowl the oceans and one of the largest fish on record. The scientific name, Carcharocles megalodon, means "giant tooth," and for good reason: Its massive teeth are almost three times larger than the teeth of a modern great white shark.  The megalodon's fossilized bones and teeth give scientists major clues about what the creature was like and when it died off.

While the popular 2018 movie, "The Meg," pits modern humans against an enormous megalodon, it's actually more than likely that the beast died out before humans even evolved. But it's difficult to pinpoint the exact date that the megalodon went extinct because the fossil record is incomplete. 

In 2014, a research group at the University of Zurich studied megalodon fossils using a technique called optimal linear estimation to determine their age. Their research, published in the journal PLOS ONE, found that most of the fossils date back to the middle Miocene epoch to the Pliocene epoch (15.9 million to 2.6 million years ago). All signs of the creature's existence ended 2.6 million years ago in the current fossil record, the authors wrote. For comparison, our earliest Homo sapiens ancestors emerged only 2.5 million years ago, during the Pleistocene epoch, according to the University of California Museum of Paleontology.

A very small portion of the Zurich study's data — 6 out of 10,000 simulations — showed a 1% chance that these giant sharks could still be alive. That chance seems pretty slim, and the researchers wrote in the study that they rejected "popular claims of present-day survival of C. megalodon."

Because no one has discovered any recent evidence of the monster — not even fossils that are any younger than 2.6 million years old — scientists agree that megalodons are long gone.