Megalodon was a giant shark that roamed the oceans for millions of years before becoming extinct some 3.6 million years ago. Scientists have been trying to determine its size for over a hundred years now.

Figuring out the size of this fearsome giant has proven to be a challenging endeavor because researchers only have fossilized teeth and vertebrae at their disposal.

Nonetheless, a team of scientists has now managed to determine the creature's size more accurately than ever before. They have published their findings in the science journal: Palaeontologia Electronica. It turns out that it was even larger than previously thought.

A fierce-looking creature - One of the main interpretations of how Megalodon appeared indicates a robust-looking shark with a comparable build to contemporary great white sharks - Credit: Herschel Hoffmeyer via Shutterstock

It all started with a school exercise. One of the three authors, Victor Perez, was helping students with a math exercise where 3D-printed replicas of fossil teeth from a real megalodon were used to calculate the shark's size.

Perez noticed that something was wrong when the results of his students ranged between 12 to 45 meters (40 to 148 feet). Initially, he thought that mistakes were made in unit conversion or that some of his students utilized the wrong equation.

However, very soon, it became clear that the error didn't stem from the students. It turned out that the equations, which have been used by scientists since 2002, are simply not as accurate as expected. "I was really surprised," Perez said. "I think a lot of people had seen that study and blindly accepted the equations."

How do scientists estimate the size of Megalodon?

When estimating the size of the Megalodon, scientists commonly use its contemporary lookalike (the great white shark) as an example. Although white sharks and megalodons belong to different families, they share a similar predatory lifestyle. In addition, both have broad, triangular, serrated teeth. According to Perez, they are excellent for hunting large prey akin to dolphins and whales.

The size difference between Megalodon and modern-day great white sharks becomes apparent very quickly when holding their teeth next to each other - Image Credit: Mark_Kostich via Shutterstock - HDR tune by Universal-Sci

Researchers calculate size based on the relationship between tooth size and total body length. One issue that arises when applying this method is that, just like in humans, the size and shape of shark teeth vary depending on where they were located in the mouth. It is, therefore, necessary to accurately identify the former location of the fossil tooth within the megalodon jaw.

Sadly most Megalodon teeth are discovered as single fossils without a clue of where they came from in relation to the jaw. So one can imagine that the scientists were thrilled when the Florida museum received a priceless donation in the form of a near-complete set of teeth from a single megalodon shark from a collector named Gordon Hubbell.

Using this newly acquired set of teeth to estimate the length of the Megalodon, it was anticipated that results would show a slight variability (just a few millimeters). But the fluctuations in estimates shot to more than 30 meters (100 feet). The farther a tooth position was from the front of the jaw, the larger the estimated size would be.

A new method of estimating shark size based on fossil teeth

In their new study, the team decided to look for a more accurate way to find out the body size of the Megalodon. They took it in a completely different direction by measuring the width of the tooth instead of the height.

The researchers analyzed a set of fossil teeth from eleven different sharks belonging to five different species, including, of course, Megalodon itself but also modern-day's great white shark and some other close relatives.

By measuring the combined width of each tooth in a row, the researchers then developed a new model. This model reveals how wide an individual tooth was in relation to its jaw. Now when a paleontologist excavates a lone megalodon tooth, they can compare its width to the average obtained in the study—making it possible to get a more accurate estimate of how big the shark really was.

how big is a megalodon?

So how big was the Megalodon shark in accordance with these new insights? It turns out that this huge predator was even larger than previously thought.

Earlier research established its size to be about 15 to 18 meters (50 to 60 feet); however, the new calculations indicate that the frightening giant would be closer in size to 20 meters (65 feet), almost the size of a blue whale (the largest animal that ever lived) which averages about 22 to 26 meters in length. (The maximum measured length of a blue whale that has been scientifically confirmed was 29.9 meters).

Some perspective - These new insights demonstrate that the Megalodon was probably closer in size to the upper limit displayed here - Credit: Scarlet23 via Wikimedia Commons

Finally, an important caveat that should be mentioned is that not all sharks are exactly the same size. Even sharks of the same species can differ in size. And so Perez warns that even this new method has a margin of error.

In addition, it is also still unclear exactly how wide Megalodon's jaw was. Unfortunately, that is difficult to determine based on his teeth alone. For example, some shark species have gaps between each tooth, while the teeth of other species overlap.

Nonetheless, scientists have made a lot of progress in devising a more accurate method to calculate a shark's size based on fossilized teeth. And perhaps equally as important, the discovery sparked enthusiasm for science in the students in a way that textbooks couldn't.

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