University of Utah paleontologist Randall Irmis and his colleagues have discovered some of the reasons why dinosaurs avoided the ancient tropics. It's partially because they just did not like the weather. You like what you're used to, after all. These researchers suggest that while dinosaurs did not enjoy the dry, hot landscape, other creatures roamed relatively freely. This included the armored aetosaurs and long-snouted phytosaurs you see in the image above. The latter is of the family that eventually gave rise to what we know today as alligators and crocodiles.