Image credit: National Geographic, "North America in the Age of Dinosaurs" During the Mesozoic Era, North America was home to an astonishing variety of dinosaurs. From the towering, herbivorous sauropods to the swift, birdlike theropods , this was a time of immense biodiversity shaped by shifting continents, evolving plants, and changing climates. One of the most fascinating features of the late Cretaceous period was the Western Interior Seaway , a vast inland sea that, at its peak, stretched nearly 1,000 miles wide. This waterway divided North America into two distinct landmasses—Laramidia and Appalachia—each hosting unique ecosystems. Predators like Tyrannosaurus rex dominated the west, while species such as Deinonychus thrived in the east. The lush landscapes were shaped by newly evolved flowering plants , including early ancestors of today’s magnolias, roses, and oaks. These plants provided food for herbivorous dinosaurs such as Triceratops and Hadrosaurus , while...