Meet the Mosasaur
The late Cretaceous Period was a time when giant marine reptiles ruled the sea. Among these reptiles was the mosasaur, a close relative of the lizards, which had a flattened tail for propelling itself through the water, and flippers for steering. Its body was streamlined, and it was probably quick and agile in the water, catching fish in its powerful jaws. Saskatchewan's mosasaurs were nothing to sneeze at; fossils found in areas between Saskatchewan Landing Provincial Park and Riverhurst tell us that they were up to 10 m in length! This exhibit illustrates what a full-size mosasaur might have looked like, lunging toward its prey.
The Last Days of the Dinosaurs
The Cretaceous Period marked the end of the Age of Dinosaurs. Saskatchewan’s fossil record shows that the province was home to both carnivorous and herbivorous dinosaurs, including meat-eaters like Tyrannosaurus rex, horned dinosaurs like Triceratops, and duck-billed dinosaurs such as Edmontosaurus. When the Cretaceous Period came to an end the dinosaurs, pterosaurs, mosasaurs and plesiosaurs, as well as a great variety of other species including micro-organisms and ammonoids, had all become extinct.
Many scientists believe that this mass extinction was caused by a meteor or comet fragment (about 10 km in diameter) that collided with the earth's surface. The impact would have created enough dust to spread around the globe, acting as a barrier to sunlight. Plants would have died off quickly, which in turn may have caused an ecological disaster. There is considerable evidence for this theory; scientists discovered a layer of iridium, a rare earth element associated with extraterrestrial objects, which coincided with the end of the Cretaceous. Contrarily, there is also evidence suggesting that the extinctions happened much more slowly, caused by gradual shifts in climate and in plant and animal communities. Whatever the cause, the face of the planet was changed forever.