Have you heard of reptiles that swim? Such animals used to exist back in the Late Cretaceous period (that is, 98–66 million years ago). Mosasaurs were discovered back in 1764 and it became clear quite quickly that they were actually marine predators, but the debate still continues on how exactly they swam. A part of the scientific community argues they moved like snakes. Bringing robust analysis and proofs, a recent study demonstrates that Mosasaurs were actually skilled swimmers, achieving swim speed comparable to sharks.