Chances are, you've seen a lot of different types of animals. But have you ever seen a dinosaur, even in a zoo? Of course not. The only dinosaurs we see today are in books, movies, or toy stores. So how do we know that the dinosaurs were ever really here? The only proof we have is in the form of fossilized bones or skeletons of these reptiles.

For years, people have been finding dinosaur bones and trying to figure out what the dinosaurs might have looked like and how they must have lived. We can only guess about some of these things, because we don't have any live dinosaurs to watch and study, and there were no people living at the time of the dinosaurs who could leave any records of what they saw. People today have at least been able to come up with a name for these creatures. The word dinosaur comes from the combination of two smaller Greek words meaning “terrible lizard.”

Because there are so many unanswered questions about the life of the dinosaurs and their world, dinosaurs probably will always be one of the world's greatest mysteries.

Some people have dedicated their lives to trying to find out more about the dinosaurs. The more they look, the more they find. New information and new types of dinosaurs are being dug up every day, which constantly makes us change the way we think about these reptiles of long ago.

Guessing Game

We guess about things every day. Doctors try to guess how tall you will be by measuring how tall your parents are. Weather reporters try to guess what the weather will be. At parties, people are always trying to guess what is inside their presents.

Scientists spend a great deal of time trying to guess when the next earthquake will happen. One of the hardest things for paleontologists is trying to guess what took place here on earth millions of years ago.

Your Turn to Guess

Guessing can be a lot of fun. If you want to challenge your friends or family to a guessing game, fill a clear container with several objects. Try things like beans, pennies, or small pieces of candy. Then show everyone your container, pass around a piece of paper and a pencil, and ask everyone to write down how many items they think are in the jar.

If you want to make it a contest with a prize, you can give an award to whoever made the closest guess. If you want to guess too, have someone who's not guessing fill the jar for you. Another way to hold a guessing game is to guess who can limbo the lowest, jump the farthest, stare at each other the longest, and so on. How close was your guess?

No Man's Land

No humans were living at the beginning of the age of the dinosaurs 230 million years ago, and it's a good thing! You probably wouldn't have wanted to live at that time unless you happen to like sharing the neighborhood with crocodiles, lots of insects, and of course, dinosaurs! The dragonflies that were on Earth millions of years ago were ten times bigger than the ones that hover over today's pools of water. These giant insects were the favorite food for the flying pterosaurs. And although dragonflies do bite, they were no match for a pterosaur.

In the day of the dinosaurs, there also were beetles, spiders, cockroaches, and eventually, snakes. Can you imagine what size these other creatures would have been if the dragonflies were that large? No one seems to know for sure when each of these creatures appeared or which dinosaur was the first. Scientists believe that the first dinosaur appeared in South America. Research also shows that the first dinosaur probably ate some type of meat, was about 3 feet tall, and ran on its back legs!

A Planet of Your Own

One way you can make a small version of the planet Earth is to make a terrarium. You will need a large clear container such as an aquarium or fish bowl, a handful of small, clean pebbles, a cup of charcoal or sand, and a small bag of potting soil. You should also have a few small fern or ivy plants, a small plastic cup or lid that you can fill with water, and a piece of plastic wrap large enough to cover the top of the container. Once you have all your materials ready, follow these steps:

• Place the pebbles in the bottom of the container.

• Follow with a layer of charcoal or sand.

• Add enough potting soil to line the container about 2 inches deep.

• Plant your ferns or ivy in this top layer and pat the soil down gently.

• Place your plastic cup or lid in the center to form a pond.

• Add some water to the pond and sprinkle a little around on your plants.

• Cover your terrarium with the plastic wrap and set your new world near a windowsill, but not in direct sunlight.

Check your terrarium every few days to see what happens. If you watch carefully, you should be able to figure out how to take care of it. For instance, if it seems to be too hot in there, you can peel back some of the wrap or move the terrarium farther away from the sunshine. If it looks too dry, you may need to add a little more water.

Left Behind

When some of the dinosaurs died, their remains were preserved naturally or turned into fossils.

The dinosaur-studying scientists known as paleontologists have searched all over the world to find these dinosaur remains to help figure out what these wonderful creatures looked like. A great many of the dinosaur discoveries occurred by accident when someone happened upon a bone fossil while they were doing something else. Going camping would be a great way to search for dinosaur fossils.

A Camping Lifestyle

If you have ever gone camping, you probably have some idea of what a dinosaur's world was like, especially if you tried “roughing it” and sleeping out under the stars! In the age of the dinosaurs, there were no houses, electricity, plumbing, or fast-food restaurants, which meant that there were no bedrooms or bathrooms, and certainly no cheeseburgers, pizza, or soda! The dinosaurs slept on the ground, ate whatever they could find, and had to brave the weather.

If you have ever been camping in a storm, you know how nice it is to get back to the safety and shelter of your own home. Although some of the many thousands of dinosaurs may have used caves for shelters, there would never have been enough caves to go around.

Pet Dinosaurs?

If humans had lived with the dinosaurs, do you think we would have dinosaur pets or dinosaur zoos? Would the dinosaurs have learned to like people-burgers? If dinosaurs had lived long enough, you might have been able to take dinosaur rides or go to dinosaur shows. There are quite a few animals that can be dangerous to humans today, such as tigers, lions, bears, and alligators. Many of them live in zoos or parks. Other animals that were dangerous long ago are now often people's pets. Even the first wild dogs and cats of the world were very dangerous.

The small dinosaurs may have been a lot like the small lizards we see in the world today. Some of these lizards make very good pets and are loved just as much as a dog or cat.

What's Your Age?

How old are you? If we didn't have records, how would you know? Sometimes older people aren't always sure of the date of their birth. A long time ago, not all babies were born in hospitals; many of them were born out in the country at their parents’ house. You certainly can't always tell someone's age by their appearance. One guessing game you could try is to have your parents’ friends try to guess your age. Then try to guess how old the people are in your family or at school.

Sometimes it's even harder to guess how old things like trees, houses, and furniture are. The first dinosaur bones really had to leave people wondering what they had found, especially if they only found part of the dinosaur! Dinosaur fossils can help a scientist support their theory about what happened in the past, and how long ago the dinosaurs lived.