What are Mosasaurs?
Mosasaurs were marine reptiles that inhabited the warm, shallow continental seas of the late Cretaceous period. They lived approximately between 98 and 65 million years ago. Though mosasaurs lived at the same time as the last dinosaurs, they are not dinosaurs but lepidosaurs, reptiles with overlapping scales. Lepidosaurs (but not mosasaurs) survived the K-T extinction that wiped out the dinosaurs, represented today by tuataras, lizards, snakes and amphisbaenians. The closest living relatives of mosasaurs are snakes, though they evolved from aigialosaurs, semi-aquatic ancestors of monitor lizards. Mosasaurs were air-breathing serpentine predators. In general, mosasaurs were huge. The smallest known was 3 m (10 ft) in length, though longer mosasaurs were more typical, with the longest known, Hainosaurus, topping out at 17.5 m (57 ft). These were true sea monsters. Early on in their existence, they would have competed with other marine reptiles such as ichthyosaurs and plesiosaurs, but th
