Hello, my name is Professor Curious Hello, my name is Professor Curious. I like to spend my time solving the great mysteries of nature. Right now I am trying to solve the mystery of the hiking dinosaurs. Maybe you can help me. This is how it all began.

One summer day I was hiking in the Alps One summer day I was hiking in the Alps. The Alps are very high mountains in Europe. I was looking through my binoculars at one of the peaks, when I saw the strangest thing. There at the top of the mountain were footprints in the rocks. Dinosaur footprints!

Dinosaurs were giant animals that lived on Earth millions of years ago Dinosaurs were giant animals that lived on Earth millions of years ago. Then they became extinct. You cannot see a live dinosaur today, not even in a zoo. But the dinosaurs left many bones and skeletons behind. They also left their footprints in mud and sand.

After many years, the mud and sand hardened into rock After many years, the mud and sand hardened into rock. Today, dinosaur footprints can be seen in some very old rocks. And there were some huge dinosaur footprints at the top of that mountain. Of course, I was very excited. But something was wrong. How did the dinosaurs get to the top of that big mountain? Did they hike up? That is how I came upon the mystery of the hiking dinosaur.

Why is it a mystery? Here are some clues about dinosaurs. Dinosaurs were big, fat and lazy. They hated hiking.

Clue #2 Dinosaurs loved to play in the water. They loved to walk barefoot through swamps and up and down beaches. The sand and mud tickled their toes. They liked that! Dinosaurs left many footprints at the beach.

So you see the problem. To leave their footprints at the top of a mountain, the dinosaurs would have had to hike there. And dinosaurs hated hiking! Yet there they were: dinosaur footprints at the top of a mountain. I am very busy trying to solve this mystery. It is very puzzling indeed! Here are some other clues to consider.

On our Earth there are six continents On our Earth there are six continents. Continents are big pieces of land surrounded by water, the oceans. We live on the continent of North America. Our mysterious dinosaur footprints are on the continent of Eurasia. The other continents are called South America, Australia, Africa, and Antarctica.

The important clue is that continents are moving, some slowly and some fast. A slow continent may move one centimeter every year. A fast continent may move sixteen centimeters every year. But no continent is ever standing still.

Since I am a very curious professor, I have often tried to feel the continent of North America moving. It works best if you stand barefoot in the grass, close your eyes, and stay very still. If you try hard enough, you might feel the continent moving! But remember it is moving very slowly, even slower than a snail.

With all the continents moving around the earth in different directions, sooner or later they bump into each other. Some continents are crashing together this very minute! But it is happening so slowly that we don’t even feel it. Many millions of years ago all the continents crashed into one another at once. The formed one big supercontinent called Pangaea. Then the continents moved apart again. If you look at a map of Africa and South America, you can see that they once fit together.

What happens when two continents crash together?

They make mountains!

To see how it happens, I tried a little experiment. I put a small rug on a smooth floor. I asked a friend to stand on one end of the rug. I got down on my hands and knees at the other end. I pretended the rug was a continent. I pretended to be the other continent about to crash into it. I slowly started pushing on my end of the rug. What do you think happened?

The rug started to fold over The rug started to fold over. When I had made many folds, I stopped pushing. I had made mountains! Try to make mountains yourself sometime.

When real continents crash together, it is the rock at their edges that get folded into high mountains. Many of the mountain ranges on the Earth were made when two continents crash together. You may have heard of some mountains that were made this way. The Appalachian Mountains were made when North America collided with Africa at the time of Pangaea. The Ural Mountains in Russia were made when Europe and Asia collided, then stuck together to form one big continent, Eurasia.

The mountains we are interested in are the Alps The mountains we are interested in are the Alps. That is where our dinosaur footprints are. The Alps were made when Africa crashed into Eurasia. This is our most important clue. Now I think we can solve the mystery of the hiking dinosaurs!

Here are some possible solutions. A group of fat and lazy dinosaurs decided to lose weight and get in shape. Huffing and puffing, they climbed to the top of the mountain and left their footprints there.

Solution #2 The dinosaurs left their footprints at the beach, where they liked to play. The someone put the beach at the top of the mountain.

Solution #3 The dinosaur footprints at the top of the mountain are fake. Someone put them their to attract tourists.

Which solution do you think is most likely to be true?

Solution #2 is correct. The dinosaurs left their footprints on the beach. Then someone put the beach at the top of the mountain. But now we have a new mystery to solve. WHO put the beach at the top of the mountain, and HOW did they do it? This mystery is very easy to solve. Here is how!

Do you remember what happens when two continents crash into each other Do you remember what happens when two continents crash into each other? What if there was a beach at the edge of the continent of Eurasia? What if the dinosaurs liked to play at this beach and left many footprints there? What if another continent, Africa, came along and crashed into Eurasia? What would happen to the beach?

To see what happened, I tried another experiment To see what happened, I tried another experiment. I drew some dinosaur footprints on a piece of paper and cut them out. Then I taped them to the rug I had used before. I pretended the rug was the continent of Eurasia. The dinosaur footprints are on a beach in Eurasia. I pretended to be the continent of Africa.

My friend stood on one end of the rug My friend stood on one end of the rug. I got down at the other end of the rug and slowly started to push. I was Africa crashing into Eurasia. I made mountains, the Alps. What do you think happened to the dinosaur footprints on the rug?

Some of the footprints got folded under Some of the footprints got folded under. Footprints like these would be very hard to find today under real mountains. But some footprints got pushed to the top of a fold, to the top of a mountain. Now that is how our mysterious dinosaur footprints got to the top of a very high mountain in the Alps. We have solved the mystery!

Who did it? Africa How did Africa do it? Africa crashed into Eurasia and folded the beach into high mountains. Some of the dinosaur footprints on the beach made it to the top of a mountain and that is where they can still be seen today.

Maybe someday you will be able to hike in the Alps or in other high mountains. Maybe you will even find some real dinosaur footprints at the top of a mountain, and if you do, you will know how they got there. Case closed! Note: The dinosaur footprints that Professor Curious saw actually exist at the top of a mountain in the Swiss National Park, in the canton of Grisons, Switzerland.

About the author, Yvonne Gil Yvonne Gil, a Smith College graduate, attended the Swiss Federal Institute of Technology in Zurich as a Fullbright Scholar in alpine geology and geophysics, and received an M.S. in geophysics from Stanford University. She is currently a geologist for an environmental consulting firm in San Francisco. She lives in Woodside, California.

About the illustrator, Bonnie Timmons Bonnie Timmons is an award-winning illustrator whose work has appeared in Time, U.S. News, the New York Times, and the Washington Post. She is also the author.illustrator of the children’s book Orville’s Outing. She lives in Philadelphia.