Humans have always been fascinated to imagine the gigantic prehistoric creatures that populated the earth before us. From dinosaurs to large mammoths, to the megalodon ( Otodus megalodon ), one of the largest carnivores that has ever existed on Earth. It is an extinct shark known mainly for its gigantic teeth found in the Neogene marine fossil record (ranging from 23 to 2.6 million years ago) in temperate tropical regions of most of the world.
Until now, science had estimated that this shark measured between 11.4 and 41.1 m in total length. However, its reproductive biology and ontogenetic growth pattern (that is, development throughout its life) have largely remained in the realm of speculation. Letting the imagination of the general public fly and creating legends with their own vision, such as that of the Warner Bros film, “Megalodon” (2018), in which a group of scientists find the great shark on an expedition in the depths of the ocean and chaos is sown.
Fictions aside, it seems that we are getting closer to knowing the real measurements of the megalodon, and the most curious thing is that this is thanks to a group of high school students. In the spring of 2015, the doctoral student geologist Víctor Pérez was working as a volunteer, collaborating with high school teachers, with molds of the great shark’s teeth. “I’d say there are maybe a dozen sets of teeth of this type known worldwide for megalodon,” says Pérez (now an assistant curator of paleontology at the Calvert Marine Museum in Maryland) in an interview for The Scientist . Being cartilaginous, extinct shark skeletons are really rare.
During class, students had to calculate the size of the megalodon using the fossil teeth and equations based on the proportions of living shark species. Described in a 2002 Kenshu Shimada article, the equations related the height of the crowns of the teeth to the length of the fish’s body. Applying the calculation to the anterior teeth, the results were bookish (about 12 meters), but upon reaching the posterior teeth, the megalodon seemed to have grown and were now estimated to be about 45 meters long. After several revisions, Pérez realized that the possible error was not in the students, but in the equations.
After Pérez presented these results at a conference in 2017, paleontologist Teddy Badaut proposed a new methodology: swapping tooth height times width in the equation. Doing so resulted in a possible 20-meter megalodon, the largest estimate to date. A new approach that would change the way of estimating the size of extinct giants, provided you have enough fossil teeth.
However, it is clear that the best way to know the true dimensions of this marine giant would be to find a skeleton or a complete jaw, the key piece of the puzzle that paleontologists continue to search. For now, Pérez tells The Scientist , the megalodon is a practical lesson in how science works: “science is constantly changing and improving.”
References:
Perez, V., Leder, R., & Badaut, T. (2021). Body length estimation of Neogene macrophagous lamniform sharks (Carcharodon and Otodus) derived from associated fossil dentitions. Palaeontologia Electronica. Published. https://doi.org/10.26879/1140
Lynch, C. (2021, August 18). Classroom Science Leads to Revision of Megalodon’s Size. The Scientist Magazine®. https://www.the-scientist.com/notebook/classroom-science-leads-to-revision-of-megalodon-s-size-69072
