A Lean, Mean Machine

Forget what the “Meg” movie franchise said about the ancient megalodon shark being a super-sized great white.

Scientists recently determined that the extinct behemoth more likely resembled an 80-foot lemon shark and sported a leaner, more elongated body better suited for energy-efficient cruising than for explosive sprints.

“Megalodon is not a simple, gigantic version of great white shark. I think that we really have to move away from that concept,” Kenshu Shimada, a paleobiologist at DePaul University and lead author of the new study, told CNN.

In their study, Shimada and his team compared partial fossil remains – particularly vertebrae – with the body proportions of 145 living and 20 extinct shark species. They found the best fit wasn’t the great white but the sleeker lemon shark.

Scaling up its proportions to megalodon’s size yielded a shockingly long predator of around 80 feet in length, without the stocky build previously assumed.

“The physics of swimming limit how stocky or stretched out a massive predator can be,” explained co-author Tim Higham in a statement. “You lead with your head when you swim because it’s more efficient than leading with your stomach.”

Beyond challenging Hollywood depictions, the findings may help explain why some marine animals, such as blue whales, grow so massive while others hit a size ceiling.

“Gigantism isn’t just about getting bigger – it’s about evolving the right body to survive at that scale,” Sternes said. “And megalodon may have been one of the most extreme examples of that.”

But the question of whether the megalodon was a steady cruiser or a burst-speed hunter remains open to debate, as well as what exactly did it look like.

“What we really need is the discovery of the complete skeleton,” Shimada told CNN. “The real test comes when we really have the complete skeleton, and then it will support or refute whether it was really skinny or stocky.”