A lemon shark
A new study suggests that the lemon shark, pictured here, is a better analogue for the megalodon's size than a great white. Albert Kok via Wikimedia Commons under CC BY-SA 3.0
Megalodons might have been longer and thinner than previously thought, according to a new study. The enormous, extinct sharks, scientists now say, grew to between 54 and 80 feet long and weighed about 94 tons. Earlier estimates had them at a maximum of 50 feet.
Based on the massive size of the animal’s serrated teeth, other scientists had suggested the megalodon resembled today’s great whites.
“Previous studies simply assumed that megalodon must have looked like a gigantic version of the modern great white shark without any evidence,” says study lead author Kenshu Shimada, a vertebrate paleontologist at DePaul University, to Jason Bittel at National Geographic.
Shimada and his colleagues first proposed that the megalodon might have had a skinnier body than great whites in a study published in the journal Palaeontologia Electronica in January 2024. The megalodon likely looked more like a mako shark, they said when that study came out.
This new paper, published in the same journal on March 9, argues that the megalodon might have been even narrower than they first proposed.
“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,” says study co-author Phillip Sternes, a shark biologist at the University of California, Riverside, in a statement.
a diagram showing an 80-foot-long megalodon, its fin size uncertain, next to a human for comparison
A graphic compares the size of a megalodon and a human, based on the new research estimating the extinct sharks grew up to 80 feet long. The exact shape, size and position of most of the fins remains unknown. Kenshu Shimada / DePaul University
No complete megalodon fossils have ever been found, so painting a full picture of the shark’s true size is difficult work. Shimada’s team used incomplete fossils of the megalodon’s vertebral column and compared them to the bodies of 165 other living and extinct shark species to extrapolate the animal’s size.
The researchers also looked at how other large sharks and whales move through water to deduce the megalodon’s shape. For instance, a bulky great white shark would struggle to move efficiently if it grew as long as a megalodon. “Although we still need direct fossil evidence, our new study suggests that it is more likely than not that megalodon must have been more slender than the modern great white shark in terms of body proportion from the hydrodynamic standpoint,” says Shimada to National Geographic.
Megalodons probably swam at a more moderate speed most of the time—since moving constantly at full speed would use a lot of energy, given their size, according to the statement. But the sharks could likely put on brief bursts of speed to snatch prey while on the hunt.
“This research not only refines our understanding of what megalodon looked like, but it also provides a framework for studying how size influences movement in marine animals,” Sternes adds in the statement.
Not everyone is convinced by this new sizing chart, however. “The hydrodynamic methods [the authors] use to try to rule out these other body forms are based primarily on whales, which have totally different skeletons and modes of swimming to sharks (i.e., vertical vs horizontal tail movements),” Jack Cooper, a megalodon researcher at Swansea University in Wales who was not involved in the study, tells Jess Thomson at Live Science. “As such, while the proposed body plan is possible, it should be treated as a working hypothesis, and previous reconstructions can’t yet be definitively ruled out.”
Until complete megalodon remains are found, estimates of their size will stay in the realm of hypothesis. In reality, the species might have looked nothing like a great white or even a lemon shark.
“The possibility cannot be eliminated until well-preserved complete or nearly complete skeletons are found,” says Shimada to National Geographic. Until that point, “we are constrained by the data.”