A longer, sleeker super predator: Megalodon’s true form
Novel study paints more accurate picture of extinct, gigantic shark
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Shark biologists now say a lemon shark, like this one, is a better model of the extinct megalodon's body than the great white shark.
view moreCredit: Albert Kok
The megalodon has long been imagined as an enormous great white shark, but new research suggests that perception is all wrong. The study finds the prehistoric hunter had a much longer body—closer in shape to a lemon shark or even a large whale.
The study team, which included researchers from University of California, Riverside and across the globe, used a novel approach to estimate the shark’s total body length, moving beyond traditional methods that rely primarily on tooth size. By examining megalodon’s vertebral column and comparing it to over 100 species of living and extinct sharks, they determined a more accurate proportion for the head, body, and tail.
The findings, published today in the journal Palaeontologia Electronica, suggest the prehistoric predator may have reached about 80 feet, or about two school buses in length. It also likely weighed an estimated 94 tons, comparable to a large blue whale, but with a body designed for energy-efficient cruising rather than continuous high-speed pursuit.
“This study provides the most robust analysis yet of megalodon’s body size and shape,” said Phillip Sternes, a shark biologist who completed his Ph.D. at UCR. “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.”
Great white sharks have a stocky, torpedo-shaped body built for bursts of speed, with a broad midsection that tapers sharply toward the tail. In contrast, lemon sharks have a leaner, more uniform body shape, with a less pronounced taper. Their longer, more cylindrical build allows for smoother, more energy-efficient swimming. If megalodon had a body structure more like a lemon shark, as this study suggests, it would have looked much sleeker than the bulky predator often depicted in popular media.
Sharks, like airplanes or Olympic swimmers, must minimize drag to move smoothly and easily.
“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 study highlights how large aquatic animals including sharks, whales, or even extinct marine reptiles, follow similar patterns when it comes to body proportions. “The physics of swimming limit how stocky or stretched out a massive predator can be,” Higham said.
The research also sheds light on megalodon’s swimming capabilities. While debates have raged over whether it was a high-speed predator or a slower, cruising hunter, the new findings suggest a balance. The shark likely swam at moderate speeds, with the ability to burst forward when attacking prey. Given its sheer size and energy demands, constant high-speed swimming wouldn’t have been efficient.
The study also indicates that as a newborn, a megalodon could have been nearly 13 feet long, roughly the size of an adult great white shark. “It is entirely possible that megalodon pups were already taking down marine mammals shortly after being born,” Sternes said.
A key breakthrough of this study was identifying the lemon shark as the best living analog for megalodon’s proportions. Unlike the great white, lemon sharks have a more elongated body. When the researchers scaled up the proportions of a lemon shark to megalodon’s estimated length, it was a near-perfect match.
“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 said.
Beyond reshaping our understanding of megalodon, the study offers insight into why only certain animals can evolve to massive sizes.
“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.”
Journal
Palaeontologia Electronica
Article Publication Date
9-Mar-2025
Megalodon’s body size and form uncover why certain aquatic vertebrates can achieve gigantism
DePaul University Paleobiology Professor Kenshu Shimada leads study with 28 experts
DePaul University
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Revised tentative body outline of 24.3 meters (80 feet) extinct megatooth shark, Otodus megalodon. Important notes: 1) the exact shape, size, and position of most fins remain unknown based on the present fossil record; and 2) an adult human (Homo sapiens) is depicted for size comparison, but it must be emphasized that the two species never coexisted
view moreCredit: (DePaul University/Kenshu Shimada).
CHICAGO — A new scientific study provides many new insights into the biology of the prehistoric gigantic shark, Megalodon or megatooth shark, which lived nearly worldwide 15-3.6 million years ago. Paleobiology professor Kenshu Shimada of DePaul University led the study along with 28 other shark, fossil, and vertebrate anatomy experts around the globe. Findings from the study will be published in the journal “Palaeontologia Electronica.”
Formally called Otodus megalodon, it is primarily known only from its serrated teeth, vertebrae, and scales in the fossil record with no known complete skeletons. Although much smaller, the modern-day great white shark (Carcharodon carcharias) also has serrated teeth, and thus the prehistoric shark has been traditionally assumed to have superficially looked like a gigantic version of the great white shark in previous studies as well as in novels and sci-fi films, including “The Meg.”
Nevertheless, a nearly complete, fossilized vertebral column, or the “trunk” portion, of O. megalodon measuring about 11 meters (36 feet) in length in Belgium has been well-researched. The new study asked a simple question, “How long were the parts not represented in the vertebral column specimen, notably the head and tail lengths of the O. megalodon individual?”
To address the question, the team of researchers from Australia, Austria, Brazil, France, Italy, Japan, Mexico, the U.K., and the U.S. surveyed the proportions of the head, trunk, and tail relative to the total body length across 145 modern and 20 extinct species of sharks. Assuming that O. megalodon had a body plan consistent with the vast majority of sharks, the team determined that its head length and tail length possibly occupied about 16.6% and 32.6%, respectively, of the total body length. Because the Belgian “trunk” vertebral specimen measures 11 meters, its head and tail were calculated to be about 1.8 meters (6 feet) and 3.6 meters (12 feet) long, respectively, making the estimated total length of 16.4 meters (54 feet) for the specific O. megalodon individual.
The largest vertebra of the Belgian specimen measures 15.5 centimeters (6 inches) in diameter, but putative O. megalodon vertebrae measuring as much as 23 centimeters (9 inches) in diameter are reported from Denmark. If the Danish vertebrae represent the largest vertebrae in the body, that individual could have measured about 24.3 meters (80 feet) long.
“The length of 24.3 meters is currently the largest possible reasonable estimate for O. megalodon that can be justified based on science and the present fossil record,” said Shimada, who belongs to DePaul University’s Department of Environmental Science and Studies and Department of Biological Sciences.
Shimada and his team’s study didn’t end there. Based on comparisons of their body part proportions, they determined that the body form of O. megalodon likely resembled superficially the modern lemon shark (Negaprion brevirostris), which has a more slender body than the modern great white shark. They also noticed that modern-day gigantic sharks, such as the whale shark (Rhincodon typus) and basking shark (Cetorhinus maximus), as well as many other gigantic aquatic vertebrates like whales (Cetacea), have slender bodies because large stocky bodies are hydrodynamically inefficient for swimming. In contrast, the great white shark with a stocky body that becomes even stockier as it grows can be large but cannot be gigantic (no more than 7 meters or 23 feet) because of hydrodynamic constraints. The implication is profound because the team unexpectedly unlocked the mystery of why certain aquatic vertebrates can attain gigantic sizes while others cannot.
The research team also included Shimada’s two former master’s students at DePaul University, Phillip Sternes and Jake Wood.
“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 [https://doi.org/10.26879/1345],” said Sternes, who is now an educator at SeaWorld San Diego.
“What sets our study apart from all previous papers on body size and shape estimates of O. megalodon is the use of a completely new approach that does not rely solely on the modern great white shark,” added Wood, now a doctoral student at the Florida Atlantic University in Boca Raton, Florida.
The new study also reassessed other biological aspects. For example, a 24.3-meter-long O. megalodon would have weighed around 94 tons, and the cruising speed estimated from scale morphology was 2.1–3.5 kilometers (1.3–2.2 miles) per hour, which is no faster than the modern great white shark. The growth patterns recorded in the vertebral specimen from Belgium suggested that O. megalodon gave live birth to newborns measuring about 3.6–3.9 meters (12–13 feet) long and that embryos nourished themselves through egg-eating behavior. Additional newly inferred growth patterns along with the known fossil record of O. megalodon and the white shark lineage support the idea that the rise of the great white shark roughly 5 million years ago likely played a role in the ultimate demise of O. megalodon due to competition.
“Many interpretations we made are still tentative, but they are data-driven and will serve as reasonable reference points for future studies on the biology of O. megalodon,” said Shimada, who hopes a complete skeleton would be discovered someday to be able to put the interpretations to test.
The new study, “Reassessment of the possible size, form, weight, cruising speed, and growth parameters of the extinct megatooth shark, Otodus megalodon (Lamniformes: Otodontidae), and new evolutionary insights into its gigantism, life history strategies, ecology, and extinction,” will appear in the forthcoming issue of Palaeontologia Electronica, which will be freely available online at https://doi.org/10.26879/1502. It is authored by: Kenshu Shimada, Ryosuke Motani, Jake J. Wood, Phillip C. Sternes, Taketeru Tomita, Mohamad Bazzi, Alberto Collareta, Joel H. Gayford, Julia Türtscher, Patrick L. Jambura, Jürgen Kriwet, Romain Vullo, Douglas J. Long, Adam P. Summers, John G. Maisey, Charlie Underwood, David J. Ward, Harry M. Maisch IV, Victor J. Perez, Iris Feichtinger, Gavin J.P. Naylor, Joshua K. Moyer, Timothy E. Higham, João Paulo C.B. da Silva, Hugo Bornatowski, Gerardo González-Barba, Michael L. Griffiths, Martin A. Becker, and Mikael Siversson.
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Journal
Palaeontologia Electronica
Subject of Research
Animals
Article Title
Reassessment of the possible size, form, weight, cruising speed, and growth parameters of the extinct megatooth shark, Otodus megalodon (Lamniformes: Otodontidae), and new evolutionary insights into its gigantism, life history strategies, ecology, and extinction
Article Publication Date
9-Mar-2025
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