The dinosaurs were unable to adapt to this new, cooler habitat.
A loss of habitat can happen naturally. Nonavian dinosaurs, for instance, lost their habitat about 65 million years ago. The hot, dry climate of the Cretaceous period changed very quickly, most likely because of an asteroid striking Earth. The impact of the asteroid forced debris into the atmosphere, reducing the amount of heat and light that reached Earth’s surface. The dinosaurs were unable to adapt to this new, cooler habitat. Nonavian dinosaurs became endangered, then extinct.