Why did the dinosaurs disappear?

When the dinosaurs lived on earth, the climate was warm and mild everywhere. Then, very slowly, things began to change. The warm swamps dried up. The air was cooler. New and different kinds of plants began to grow.

There were many animals that were able to get along with these changes, and they didn’t die out. But perhaps the dinosaurs could not live in the new kind of world. They were cold-blooded, and they could not live comfortably in cool weather.

The plant-eaters could not eat the new kinds of plants, which had tougher stems and leaves. If the plant-eaters died out because their food had become scarce, you know how that would affect the meat-eaters. They would die out, too, because they had to live on the plant-eaters.

what happened to many of the dinosaur eggs?

Another explanation is the story of what happened to the dinosaur’s eggs. The big beasts laid their giant eggs right on the ground. They didn’t hide them, or protect them, or stay nearby to guard them. When the eggs hatched, the baby dinosaur had to look after themselves. Other animals, including some of the smaller meat-eating dinosaurs, would get at the unprotected eggs. They made a fine, safe meal for a hungry little animal that had to hide from the big dinosaurs most of the time.

Many dinosaurs eggs were surely destroyed in this way. But that alone could not have caused the whole dinosaur family to die out. The big sea reptiles died out at the same time, and their young were born alive in the water. So egg robbers cannot have been to blame completely.

Another idea is that there was a special kind of dinosaur sickness that killed the giants. Scientists wonder if there might not have been a disease that spread all over the world, affecting only dinosaurs and the big air and water reptiles. But then, why did it skip other reptiles?

Maybe the answer is a combination of all these ideas. And maybe the warm-blooded furry mammals had something to do with it.