Phil Harmon, age 8, of Richmond, Va., for his question:

 How long ago did the dinosaurs live?

Lets go back and say goodbye to the last of the dinosaurs. We must put the clock back sixty million years. The last of the big fellows was very uncomfortable. For the weather was changing. The last of his warm, wet swamps was dry and cold. The big fellow was a lizard. The cold was too much for him and he was too big to hide himself in a cozy burrow.

What's more, a lot of ratty little animals were around. They dug out the dinosaur eggs and ate them before they could hatch. The last of the dinosaurs was a very unhappy fellow, everything went wrong for him. And sixty million years ago, he said goodbye to the unfriendly world.

Dinosaurs were big lizards. And lizards are reptiles, When the dinosaurs lived, most of the animals in the world were reptiles. They appeared in all shapes and sizes. We call this long reign the Age of Reptiles. And the Age of Reptiles lasted about 120 million years. All that time the world was warm. There were plenty of marshy lakes and shallow waters along the shores. Things were just right for reptiles.

The long reign began about 180 million years ago. At first the lizards were fairly small. But they grew and grew. Soon, some of them were six feet, then 20 feet long. One fellow looked like an ostrich. He ran on his strong back legs. He had a long neck and a small head. His tail was a lizard tail and of course he had scales instead of feathers.

Some of the smaller lizards did not survive. Others grew still bigger as time went by, one big fellow was 70 feet long and weighed 36 tons. He was as big as a small house and tall enough to look over the roof. This whopper was Brontosaurus, the thunder lizard. He enjoyed life in swamps and he fed on water weeds.

While big Brontosaurus lived, certain dinosaurs grew wings and took to the air. Flying became fashionable. Later on, these flying lizards developed into true birds. The family tree of our birds branches off from the dinosaurs.

Big Brontosaurus and his friends said goodbye long before the Age of Reptiles came to any end. Other dinosaurs came along. Same of them were very toothy fellows. For meat eating became more and more fashionable.

One of these meat eaters was a huge fellow called Tyrannosaurus. This fellow ran on his long, strong hind legs. He stood 20 feet high, taller than three tall men. His head was the size of a big packing case. His giant jaws were filled with dagger shaped teeth six inches long. Tyrannosaurus is said to be the biggest and the cruelest hunter that ever stalked the earth.

We do not know for sure why the big lizards finally said goodbye. The weather seemed to go against them. Food ran short. Smaller animals came along and they were more clever than the big dull dinosaurs. At any rate, after 120 million years the Age of Reptiles ended. The last of the big lizards perished 60 million years ago ‑ some 58 million years before the human family came to live in the world.