“I was going around, checking, like, did you use the wrong equation? Did you forget to convert your units?” said Perez, currently the assistant curator of paleontology at the Calvert Marine Museum in Maryland. “But it very quickly became clear that it was not the students that had made the error. It was simply that the equations were not as accurate as we had predicted.”
The new approach
Perez’s math exercise demonstrated that the equations in use since 2002 were generating different size estimates for the same shark based on which tooth was being measured. Because megalodon teeth are most often found as standalone fossils, Perez focused on a nearly complete set of teeth donated by a fossil collector to design a new approach.
Perez also had help from Teddy Badaut, an avocational paleontologist in France, who suggested using tooth width instead of height, which would be proportional to the length of its body. Another collaborator on the revised method was Ronny Maik Leder, then a postdoctoral researcher at the Florida Museum, who aided in the development of the new set of equations.
The research team analyzed the widths of fossil teeth that came from 11 individual sharks of five species, which included megalodon and modern great white sharks, and created a model that connects how wide a tooth was to the size of the jaw for each species.
“I was quite surprised that indeed no one had thought of this before,” shared Leder, who is now director of the Natural History Museum in Leipzig, Germany. “The simple beauty of this method must have been too obvious to be seen. Our model was much more stable than previous approaches. This collaboration was a wonderful example of why working with amateur and hobby paleontologists is so important.”
Why use teeth?
In general, almost nothing of the super-shark survived to this day, other than a few vertebrae and a large number of big teeth. The megalodon’s skeleton was made of lightweight cartilage that decomposed after death. But teeth, with enamel that preserves very well, are “probably the most structurally stable thing in living organisms,” Perez said. Considering that megalodons lost thousands of teeth during a lifetime, these are the best resources we have in trying to figure out information about these long-gone giants.
Researchers suggest megalodon’s large jaws were very thick, made for grabbing prey and breaking its bones, exerting a bite force of up to 108,500 to 182,200 newtons.
Limitations of the new model
While the new model is better than previous methods, it’s still far from perfect in precisely figuring out the sizes of animals which lived so long ago and left behind few if any full remains. Because individual sharks come in a variety of sizes, Perez warned that even their new estimates have an error range of about 10 feet when it comes to the largest animals.