Did you ever have a bad dream? Imagine that you were looking out your bedroom window and you saw a giant dinosaur with its huge mouth full of sharp teeth staring back at you. Luckily, things like that only happen in dreams or movies.

At one time the area where dinosaurs lived was much different. The climate may have been very warm and tropical. There were many plants for the plant-eaters and plenty of animals for the meat-eaters.

Dinosaurs became extinct millions of years ago. No one is certain why this happened. Here are a few theories: (A theory is a scientific explanation using evidence.)

1. Something happened that changed the climate. Maybe a huge comet or a meteor struck the earth and created large clouds of dust that blocked out the sun. The amount of rainfall changed, causing a drought that affected all of the plants and animals.
2. Scientists know that animals can be affected by diseases. Maybe a disease was spread rapidly among the dinosaurs that caused them to become sick or die.
3. A sudden change in temperature can harm animals such as reptiles. Putting a turtle outside in the snow would cause it to die if it were left there for very long. It is possible that the weather became very cold during the time of the dinosaurs causing them to die out.

Write it!

Write a story about how dinosaurs became extinct. Include two reasons that may have caused this to happen. Make sure that you also illustrate your story. Share your story with friends or parents.