Mosasaur is a prehistoric marine reptile from the North America and Western Europe. It lived during the last days of the cretaceous period. It is believe that its earliest member started on land and eventually returned to the ocean. Mosasaur is the top predator of the ocean at the time. It ate everything that it can catch. They are good parents, they will protect there off spring after they are born. They will attack other preditors, by using its speed and size. Like all Marine Reptiles they need air to live, so Mosasurus after there birth must rush to the surfice to get a breath of fresh air, even the adults need some breath of fresh air, but can surivie under water for many hours.