<p><img src="https://static1.businessinsider.com/image/60c0961cfde7960018aace07-2400/shutterstock_371212546.jpg" border="0" alt="megalodon shark week" data-mce-source="Shutterstock" data-mce-caption="An illustration of a megalodon."></p><p></p><bi-shortcode id="summary-shortcode" data-type="summary-shortcode" class="mceNonEditable" contenteditable="false">Summary List Placement</bi-shortcode><p>A high-school trip prompted a scientific discovery when students found that a long-standing calculation to determine the size of megalodons based on their teeth was not precise enough.</p><p>The finding prompted scientists to develop a new equation, which extends the average size of the prehistoric beasts to about 65 ft, an extra 10% or so on the prior estimated length of 50ft to 60ft.</p><p>That would put a megalodon at around four times the size of a great white shark, which grow to around 15ft.</p><p>This new estimate <a href="https://palaeo-electronica.org/content/2021/3284-estimating-lamniform-body-size">was published on June 7</a> in the peer-reviewed journal Palaeontologia Electronica.</p><p>The new method is better than the previous one, "which seems to have a number of problems," Pimiento said.</p><p><img src="https://static5.businessinsider.com/image/60c08e0a6b60c70019c29ca7-2000/267095_web.jpeg" border="0" alt="Megalodon" data-mce-source="Kristen Grace/Florida Museum of Natural History" data-mce-caption="The lower jaw of a Otodus megalodon, modelled from a near-complete set of fossils from a single shark, at the Florida Museum of Natural History." data-link="https://www.eurekalert.org/multimedia/pub/267095.php'from=505570"></p><h2>A calculation "blindly accepted" since 2002</h2><p>Megalodon sharks lived about from about 23 million years ago to around 3.6 million years ago.</p><p>Like other sharks, their skeletons were primarily made up of cartilage, so scientists get relatively little physical evidence of their bodies. What is left are teeth and a few vertebrae, from which they can extrapolate other characteristics.</p><p>Since 2002, a calculation based on the height of megalodon's teeth was commonly used to determine their length. </p><p>But a field trip of high school students from California to the Florida Museum of Natural History brought down that equation.</p><p>The students were told to apply the calculation to replicas of a set of teeth of a single megalodon acquired by the museum.</p><p>Using the calculation, they came up with wildly different estimates for the length of the same shark: from about 40 to 148 feet. </p><p>"I was really surprised," then-PhD student Victor Perez, who led the study and is now an assistant curator of paleontology at the Calvert Marine Museum in Maryland <a href="https://www.eurekalert.org/pub_releases/2021-06/fmon-slg060721.php">said in a press release accompanying the study</a>. "I think a lot of people had seen that study and blindly accepted the equations."</p><p><img src="https://static1.businessinsider.com/image/60c08eae6b60c70019c29ca9-1777/267096_web.jpeg" border="0" alt="megalodon tooth" data-mce-source="Kristen Grace/Florida Museum of Natural History" data-mce-caption="The jagged fossilised teeth are almost all that is left of the of megalodon after the cartilage disappears." data-link="https://www.eurekalert.org/multimedia/pub/267096.php'from=505570"></p><h2>A new equation based on the width of the teeth</h2><p>Working with fellow researcher Ronny Maik Leder, Perez developed a new calculation for the shark's length. This time, they used the width of the teeth to determine the size of the animal's jaw. </p><p>"I was quite surprised that indeed no one had thought of this before," Leder, now director of the Natural History Museum in Leipzig, Germany, said in a press release. </p><p>The team's method have a range of error, about 10 feet when applied to the largest individuals, Perez said.</p><p>Nevertheless, it shows that megalodon could reach larger sizes than previously thought, Pimiento said. </p><p>The new method has limitations, she said, as it still relies on knowing where the teeth go in the jaw, which could lead to errors.</p><p><a href="https://www.businessinsider.com/megalodon-sharks-bigger-than-thought-after-high-school-trip-2021-6#comments">Join the conversation about this story »</a></p> <p>NOW WATCH: <a href="https://www.businessinsider.com/navy-usns-comfort-hospital-ship-new-york-coronavirus-covid-19-2020-3">How the Navy's largest hospital ship can help with the coronavirus</a></p> Click here to read full news..