text: does the mosasaur still exist today? the mosasaur is a fossil animal.it lives in the sea.it looks like a dinosaur and it is a carnivor. what klaus said about mosasaurs is correct.  the mosasaurs went extinct at the end of the cretaceous period 65 million years ago, at the same time that the dinosaurs did, and there has been no evidence that any of them survived past that period.