Megalodon

The largest predatory shark known, and a case study in estimating an animal from teeth and backbone. Because shark skeletons are cartilage, megalodon survives mostly as teeth and the occasional vertebral column. One such column from Belgium, about 11 meters of spine, implies an individual around 16.4 meters long. A 2025 study argued megalodon was slimmer than a scaled-up great white, closer in shape to a lemon shark, and set 24.3 meters as the largest length the fossils can reasonably justify, for a weight of roughly 94 tons. That upper figure is a ceiling, not a typical adult, and it still sits below the blue whale's measured length and weight.