The Cretaceous was the last period when dinosaurs were the dominant land animals. "Triceratops", "Tyrannosaurus" and "Velociraptor" lived at this time. The huge "Mosasaurus" was the dominant marine predator. In the Cretaceous period, birds became more diverse. Flowering plants developed more, and became the dominant plants on land. The Upper Cretaceous ended with the K/T extinction event.