In fact, they're the largest cold-blooded animal. Some truly gigantic whale sharks have been documented in fisheries. One, caught off Taiwan, was 20 metres long and weighed 34 tons. Another shark from the same area weighed 42 tons, though its length apparently wasn’t recorded. An 18.8-metre whale shark was landed in India, too. Based on the fossil record, whale sharks are likely to be the biggest fish to have ever lived. Megalodon, a huge, extinct whale-munching predatory shark famous for battling Jason Statham, is thought to have reached around 18 metres. The largest-discovered remains of a plankton-feeding Jurassic bony fish, Leedsichthys problematicus, indicate a maximum length of around 16.5 metres.