If Meg 3 ever happens, the filmmakers might need to ditch the oversized great white shark trope. A new study published in Palaeontologia Electronica found that the famous megalodon wasn’t just an outsized version of today’s great white shark. Researchers now say this ancient super-predator was a longer, more streamlined animal built more like a modern lemon shark or even a large whale.

Crunching the Megalodon numbers

The megalodon (formal name Otodus megalodon) roamed Earth’s oceans between 15 and 3.6 million years ago. Though it is known mostly from enormous fossil teeth, one find revealed parts of its skeleton, particularly a fossilized vertebral column, or the “trunk” portion, of O. megalodon measuring about 11 meters (36 feet) in Belgium. The latest study begged the question “so, how big were they actually”?

A team of 28 scientists estimated just how big this vertebral column’s missing sections—namely the head and tail—would have been. Drawing on measurements from 145 modern shark species and 20 extinct species, the researchers concluded that the Belgian megalodon likely measured around 54 feet (16.4 meters) from nose to tail.

“This study provides the most robust analysis yet of megalodon’s body size and shape,” said Phillip Sternes, a shark biologist at the University of California-Riverside (UCR) who also studied at DePaul University, another institution involved in the research. “Rather than resembling an oversized great white shark, it was actually more like an enormous lemon shark, with a more slender, elongated body. That shape makes a lot more sense for moving efficiently through water.”

But the evidence doesn’t stop there. In the same study, putative megalodon vertebrae discovered in Denmark—larger than those found in Belgium—suggest some individuals could have grown to a whopping 80 feet (24.3 meters). At that size, this shark may have weighed about 94 tons. This upper limit, according to Shimada’s team, is “the largest possible reasonable estimate” that’s backed by current fossil data.

Sleeker than a great white

The megalodon’s more slender form likely reduced water resistance and improved energy efficiency—an essential trait for a predator that could exceed 50 feet. The new findings help explain why other enormous marine creatures such as whale sharks, basking sharks, and whales also tend to have more streamlined physiques: carrying around an overly bulky body would make daily movement too difficult and energy-intensive.

“You lead with your head when you swim because it’s more efficient than leading with your stomach,” said Tim Higham, UCR biologist who contributed insights to the study on how animals move through water. “Similarly, evolution moves toward efficiency, much of the time.”

The researchers also examined the growth patterns preserved in fossilized vertebrae. These patterns suggest that megalodon pups were born live—somewhere between 12 and 13 feet (3.6–3.9 meters) long—and continued to grow by eating unfertilized eggs in the womb (a behavior still seen in certain modern sharks). Once in the open ocean, the young megalodon may already have been large enough to prey on marine mammals.

While the megalodon’s overall speed probably wasn’t exceptional for a shark—similar to modern white sharks, around 1–2 miles (2–3 kilometers) per hour when cruising—its streamlined shape could have enabled bursts of faster movement during hunts. This balance of moderate cruising speed and sudden acceleration would have been key to capturing prey.

Not a speedy demon, but deadly

Understanding the megalodon’s body size and shape helps us see why only certain marine animals, such as whales or whale sharks, can grow to enormous proportions. Large bodies can be extremely effective for traveling long distances and capturing prey, but they require very efficient swimming styles and feeding strategies. Megalodon likely thrived by being big enough to tackle large prey and exploit vast feeding grounds, yet streamlined enough to keep moving without burning too much energy.

The findings still support the idea that competition with emerging predators (including the rise of the great white shark) may have contributed to its demise. However, the researchers say many of these interpretations remain tentative; only a complete megalodon skeleton would truly confirm its full body shape. They hope these new data-driven insights will guide future research into the biology, ecology, and evolutionary history of one of Earth’s most awe-inspiring and celebrated ocean giants.

“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…Our new study has solidified the idea that O. megalodon was not merely a gigantic version of the modern-day great white shark, supporting our previous study.”

For now, at least, it appears that our mental image of megalodon should shift from a bulky movie monster to a truly massive—but unexpectedly sleek—hunter of prehistoric seas.