The most noticeable difference between the extinct Megalodon and its modern-day counterpart, the Great White Shark, is that the Megalodon was much larger. Scientists attempt to discern more subtle differences between the two species from evidence found in fossilized teeth of the Megalodon.

Because the Megalodon, like the Great White Shark, was made of mostly cartilage and few bones, there is little fossil evidence of this creature that went extinct approximately 3 million years ago. The surviving fossils are of Megalodon teeth, from which scientists can estimate that its body grew from 40 to 70 feet long and weighed up to 25,000 kilograms. Comparatively, the average Great White Shark is 15 to 25 feet and weighs in at 3,300 kilograms. This size difference allowed the Megalodon to prey on larger animals, such as whales, that are usually off the Great White Shark’s menu.

Close examination of fossilized Megalodon teeth reveals various differences from its modern-day cousin, such as the depth of teeth in the mouth and changes in tooth serration quality and number as the animal ages. The fossilized teeth also reveal the nature of nearby nerve paths and blood vessels, which are larger and clustered in Great White Sharks, but smaller and further apart in the Megalodon.

These nuanced differences fuel a debate among scientists whether to reclassify the Megalodon as evolutionarily further removed from the Great White Shark or not.