The Houston Museum of Natural Science hosts a range of permanent and special exhibitions, including Sharks! The Meg, The Monsters, & The Myths. The extensive exhibit offers insight into sharks both ancient and modern, from the megalodon to the great white, and everything in between.
The megalodon is generally considered to be the largest species of shark ever to exist on the planet. Size estimates vary from 50 to 60 feet in length, which would be about three times larger than the biggest great white shark ever observed. The size is more comparable to whale sharks, which max out at just under 65 feet in length. While the megalodon has sometimes been framed by the media as an ancient monster that may still be roaming the open seas, including in a controversial 2013 Discovery Channel documentary, scientists know a great deal about the animal, including its final days as rulers of the earth’s oceans.
The Otodus megalodon first appeared in the early Miocene epoch, about 23 million years ago, and was last recorded in the Pliocene epoch, roughly 3.6 million years ago. Early fossil records suggests the megalodon was closely related to the great white, but more recently the animal has been recognized as a prominent member of the now extinct Otodontidae family. While the size of the megalodon places it among the largest sharks of all time, it should be noted that a complete fossil has never been recovered and the exact size of the shark is unknown. A length of about 34 feet is most likely, but a maximum length of nearly 70 feet is not considered impossible.
While the exact size of the megalodon is not known, the predator’s impact on the marine ecosystem is more clear to modern researchers. The fragmentary megalodon remains that have been recovered suggest a global distribution, supporting the idea that megalodon was an apex predator, or at the top of its food chain. Some of the hunter’s most common targets were likely whales, sea turtles, and other large marine life.
Despite the animal’s fearsome build, megalodon’s reign did not go unchallenged. A variety of smaller killer whale ancestors populated the earth’s seas, while larger predators including macro-raptorial sperm whales also competed for the sea’s resources. That said, the shark’s preference for warmer waters is likely the key factor to megalodon’s demise. Several ice ages cooled the planet’s waters, while baleen wheels, a favored prey item, began inhabiting more polar regions. Around the same time, a gigantism trend made the available baleen whales more challenging to hunt.
The great white shark was never a serious threat to the megalodon, but the two species did overlap. The first white sharks can be traced back to the Miocene epoch, about 23 million years ago, though they may be even older. Examples of prehistoric white sharks include the Carcharodon hubbelli, Carcharodon hastalis, and Carcharomodus escheri, all of which were comparable in size to the modern great white, Carcharodon carcharias.
Like the megalodon, the great white shark is an apex predator, though it also faces competition from cetaceans in the form of orca whales. In fact, encounters between the two animals seem to favor the orca, which may actually have developed a technique for hunting and killing great whites.
