11 Disappearing Dinosaurs

Disappearing Dinosaurs written by Pam Holden

fossil Why did the dinosaurs disappear from Earth? Lots of different ideas have been given, but nobody knows for sure. These amazing creatures disappeared long before people began to live on Earth. They have been gone for millions of years! We are now beginning to learn some things about their life here. This is because the bones of dinosaurs have been found in many countries in the past 350 years. Skeletons have been found preserved as fossils in rocks and swamps.

skeleton The bones and body parts are studied by scientists called paleontologists, who learn new facts about dinosaurs. They rebuild the old skeletons to show what the many different kinds looked like. We now know more about their size and shape, what they ate, and how they moved. Many facts are known, but still nobody can be sure how or why they disappeared.

glacier Did the dinosaurs all disappear because of a sudden change in the world's climate? Was the world suddenly too cold or too hot for them to survive? One idea is that huge glaciers spread out and covered Earth's surface, making it too cold for anything to grow. If plants could no longer grow, then all the plant-eaters would have starved and died out. There would have been nothing left for the meat-eaters to hunt for food.

Some scientists think that giant volcanoes may have made the Earth too cool. Gas from volcanic eruptions, as well as dust in the air and the oceans, would have blocked the sunlight. Enormous fires and storms would have made Earth an impossible place for the dinosaurs to survive. Scientists can research this idea by studying deep craters left in Earth's surface by eruptions.

meteor Did the mighty dinosaurs become extinct because burning comets or meteors crashed to Earth and destroyed their habitat? If all plant life was burnt away by chunks of red-hot rock, the dinosaurs' food chain would have quickly broken down, leaving them to starve to death.