How long ago were dinosaurs alive?

The earliest dinosaurs were alive about 240 million years ago. The most recent ones, like Tyrannosaurus rex and Triceratops, were alive up until 65 million years ago. Then, they all disappeared from the Earth. No-one knows exactly why, but there are lots of theories. Probably it was a combination of several different causes. Some of the books about dinosaurs in your school library describe some of these theories.

How were dinosaurs born?

We know that many dinosaurs came from eggs, because fossil eggs have been found. There is a picture of a baby Oviraptor dinosaur fossil, still inside its egg, in the Ottawa Citizen newspaper for Friday, November 4, so we know that Oviraptors hatched from eggs. Fossil eggs of other kinds of dinosaurs have been found, too, like Maiasaura. Probably all dinosaurs were born from eggs, just like birds are today, but maybe some of them were born live from their mothers.

We don't know for sure, and we might never find out.

How do you know if the dinosaurs ever lived?

People have found fossils of many, many dinosaurs. They have found skeletons, footprints, eggs, and even the outlines of their skins left in the mud millions of years ago. The Ottawa Citizen newspaper for Friday, November 4 even has a picture of a fossil of a baby dinosaur inside its egg, just about ready to hatch. There are fossils of dinosaurs of all different ages, including mother dinosaurs looking after their nests, and herds of dinosaurs travelling together. These fossils tell scientists a lot about how dinosaurs lived, even though no human being has ever seen a live dinosaur. If you are interested in dinosaurs, your school library has lots of interesting books about them.