Everyone knows that the biggest predator in the ocean these days is the great white shark, but that wasn't always the case. Millions of years ago, great whites were small fries compared to some of their massive contemporaries.
The biggest one of all was the megalodon -- a shark of insane proportions by today's standards. Even though they supposedly died out years ago, some speculate that a few megalodons might still be lurking in the depths.
Scientists first discovered evidence of megalodons during the Renaissance in Europe.
There are numerous accounts of naturalists at the time encountering giant, triangular teeth that were embedded in rock formations. However, it wasn't until the mid-1800s that the megalodon got its name.
According to fossil evidence, most megalodons were between 50 and 80 feet long.
To put that into perspective, the biggest great white sharks today only grow up to 20 feet in length.
While many of us might be happy that this immense creature is long dead, there are those who believe that it's still around.
As evidence, they cite the discovery of other prehistoric ocean creatures that were also thought to be extinct.
The fact that we've only explored 5 percent of our oceans only adds insult to injury.
They also cite a few (if questionable) eye-witness accounts of megalodon encounters. Take the 1918 sighting of a 100-foot shark off the coast of Australia by a pair of experienced fishermen, for example.
(via Elasmo Research)
While it's very likely that the megalodons are gone, it's still interesting to consider the possibility that they're here. The fact remains that we know very little about most of Earth's oceans. Perhaps there's a gigantic shark out there hiding in the dark.