Dinosaurs are a group of reptiles that ruled the Earth during the Mesozoic Era, 252 to 66 million years ago. As a group, dinosaurs are some of the most successful animals the world has ever known, thriving on every continent and in every kind of habitat. Although most dinosaurs are now extinct, one kind – birds – is still with us today.
During the Mesozoic, many kinds of dinosaurs evolved and went extinct. Dinosaur Park preserves one particular dinosaur ecosystem that existed in Maryland 110 million years ago. However, these dinosaurs did not live alone. They shared their world with a variety of other animals, including crocodiles, insects, and fish. Our own distant ancestors – small, shrew-like mammals – also lived in the shadow of the dinosaurs.