About The Author M.J. Cosson lives in Texas with her husband, two dogs, and cat. She has written many books for ages second grade through young adult. She has a special fondness for big animals such as elephants and whales, and hopes that there will always be room on Earth for them.
Table of Contents Finding Troodon
5
Where Troodon Lived
6
Troodon’s Big Head
8
Troodon’s Thin Body
11
How Troodon Moved
14
Editor: Robert Stengard-Olliges
Troodon’s World
17
Cover and page design by Nicola Stratford
Troodon’s Food
18
Troodon’s Family Life
19
The End of Troodon
22
Glossary
23
Further Reading/Website
24
Index
24
© 2007 Rourke Publishing LLC All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical including photocopying, recording, or by any information storage and retrieval system without permission in writing from the publisher. www.rourkepublishing.com Photos/Illustrations: Cover © Joe Tucciarone; Title page and pages 4, 5, 7, 8, 10, 16, 18 © Jan Sovak; page 12 © Luis Rey; page 15 © Michael Fredericks; page 19 © Yale Peabody Museum; page 20 © American Museum of Natural History Library
Library of Congress Cataloging-in-Publication Data Cosson, M. J. Troodon / by M.J. Cosson. p. cm. -- (North American dinosaurs) Includes bibliographical references and index. ISBN 978-1-60044-254-4 (hardcover) ISBN 978-1-60044-336-7 (paperback) 1. Troodon--Juvenile literature. 2. Dinosaurs--North America--Juvenile literature. I. Title. II. Series. QE862.S3C67 2007 567.914--dc22 2006016263
Printed in the USA CG/CG
www.rourkepublishing.com –
[email protected] Post Office Box 3328, Vero Beach, FL 32964
1-800-394-7055
About The Author M.J. Cosson lives in Texas with her husband, two dogs, and cat. She has written many books for ages second grade through young adult. She has a special fondness for big animals such as elephants and whales, and hopes that there will always be room on Earth for them.
Table of Contents Finding Troodon
5
Where Troodon Lived
6
Troodon’s Big Head
8
Troodon’s Thin Body
11
How Troodon Moved
14
Editor: Robert Stengard-Olliges
Troodon’s World
17
Cover and page design by Nicola Stratford
Troodon’s Food
18
Troodon’s Family Life
19
The End of Troodon
22
Glossary
23
Further Reading/Website
24
Index
24
© 2007 Rourke Publishing LLC All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical including photocopying, recording, or by any information storage and retrieval system without permission in writing from the publisher. www.rourkepublishing.com Photos/Illustrations: Cover © Joe Tucciarone; Title page and pages 4, 5, 7, 8, 10, 16, 18 © Jan Sovak; page 12 © Luis Rey; page 15 © Michael Fredericks; page 19 © Yale Peabody Museum; page 20 © American Museum of Natural History Library
Library of Congress Cataloging-in-Publication Data Cosson, M. J. Troodon / by M.J. Cosson. p. cm. -- (North American dinosaurs) Includes bibliographical references and index. ISBN 978-1-60044-254-4 (hardcover) ISBN 978-1-60044-336-7 (paperback) 1. Troodon--Juvenile literature. 2. Dinosaurs--North America--Juvenile literature. I. Title. II. Series. QE862.S3C67 2007 567.914--dc22 2006016263
Printed in the USA CG/CG
www.rourkepublishing.com –
[email protected] Post Office Box 3328, Vero Beach, FL 32964
1-800-394-7055
Troodon lived in what is now the western part of the United States.
Finding Troodon At first, all we had of Troodon was one tooth. Dr. Ferdinand Hayden traveled the West in the mid-1800s. He took notes. He helped people in the East understand the West. In 1855, he found a fossil of a strangelooking tooth in Montana. He gave it to his friend back East, Dr. Leidy. Dr. Leidy wrote about the tooth. He thought the tooth had belonged to a large lizard. In 1856, he named the tooth Troodon. As it turns out, the tooth wasn’t from a lizard. Troodon was one of the first dinosaurs found in the United States. This drawing shows how Troodon’s teeth would have looked inside its mouth.
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5
Troodon lived in what is now the western part of the United States.
Finding Troodon At first, all we had of Troodon was one tooth. Dr. Ferdinand Hayden traveled the West in the mid-1800s. He took notes. He helped people in the East understand the West. In 1855, he found a fossil of a strangelooking tooth in Montana. He gave it to his friend back East, Dr. Leidy. Dr. Leidy wrote about the tooth. He thought the tooth had belonged to a large lizard. In 1856, he named the tooth Troodon. As it turns out, the tooth wasn’t from a lizard. Troodon was one of the first dinosaurs found in the United States. This drawing shows how Troodon’s teeth would have looked inside its mouth.
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5
Where Troodon Lived For a long time, no one knew what Troodon looked like. Over the next 150 years, more fossils were found. Troodon lived in the northwest United States and Canada. Troodon’s teeth and bones have been found in Montana and Wyoming. More fossils have been found in Alberta, Canada, and in north Alaska. Smaller dinosaurs’ fossils have been found in Asia and other parts of the world. They are like Troodon. We still don’t have all the pieces of Troodon. We have enough to make some good guesses about this dinosaur, though.
Based on the fossils that have been found so far, experts think that Troodon might have looked like this.
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7
Where Troodon Lived For a long time, no one knew what Troodon looked like. Over the next 150 years, more fossils were found. Troodon lived in the northwest United States and Canada. Troodon’s teeth and bones have been found in Montana and Wyoming. More fossils have been found in Alberta, Canada, and in north Alaska. Smaller dinosaurs’ fossils have been found in Asia and other parts of the world. They are like Troodon. We still don’t have all the pieces of Troodon. We have enough to make some good guesses about this dinosaur, though.
Based on the fossils that have been found so far, experts think that Troodon might have looked like this.
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Troodon had a long head with a big brain.
Troodon’s Big Head Troodon had a long skull. It had the biggest head and brain for its size of any dinosaur. Troodon was probably the smartest dinosaur. Why do we think so? Its brain was like an ostrich’s brain.
8
Most dinosaur brains are like reptiles’ brains. An ostrich is smarter than any reptile. Troodon had large eyes that faced forward. It could see well up close and far away. Scientists think that Troodon hunted at night. The front part of Troodon’s face was U-shaped. Its nose was fairly small. Troodon probably used its sense of sight more than its sense of smell. Troodon had many small teeth in its long jaws. Some teeth were smooth. Some teeth had sharp, rough edges that could tear flesh. Troodon’s name means “wounding tooth.” It is a good name— Troodon was a meat eater.
9
Troodon had a long head with a big brain.
Troodon’s Big Head Troodon had a long skull. It had the biggest head and brain for its size of any dinosaur. Troodon was probably the smartest dinosaur. Why do we think so? Its brain was like an ostrich’s brain.
8
Most dinosaur brains are like reptiles’ brains. An ostrich is smarter than any reptile. Troodon had large eyes that faced forward. It could see well up close and far away. Scientists think that Troodon hunted at night. The front part of Troodon’s face was U-shaped. Its nose was fairly small. Troodon probably used its sense of sight more than its sense of smell. Troodon had many small teeth in its long jaws. Some teeth were smooth. Some teeth had sharp, rough edges that could tear flesh. Troodon’s name means “wounding tooth.” It is a good name— Troodon was a meat eater.
9
Troodon’s Thin Body A grown Troodon was about the size of a small adult human. Troodon was about 6.5 feet (2 m) long. It stood about 4.5 feet (1.3 m) tall. It probably weighed about 100 pounds (45 kg). Experts aren’t sure what Troodon’s skin was like. Troodon might have had feathers like a bird or scales like a lizard.
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11
Troodon’s Thin Body A grown Troodon was about the size of a small adult human. Troodon was about 6.5 feet (2 m) long. It stood about 4.5 feet (1.3 m) tall. It probably weighed about 100 pounds (45 kg). Experts aren’t sure what Troodon’s skin was like. Troodon might have had feathers like a bird or scales like a lizard.
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Scientists do know that Troodon had a long neck. Its arms and legs were long, too. Troodon’s feet had three sharp claws that pointed forward. Another claw was on the side. Troodon also had a long, stiff tail.
Birds might have come from dinosaurs such as Troodon. Many things are alike. • Troodon’s middle ear was shaped like a bird’s. • Troodon’s teeth were smaller than older dinosaurs’ teeth. Birds don’t have teeth. Small teeth could have been a step toward no teeth. • Troodon’s brain had air sacs, and so do birds’ brains. • Troodon’s wrist moved sideways, just like birds and bats move their wings.
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Scientists do know that Troodon had a long neck. Its arms and legs were long, too. Troodon’s feet had three sharp claws that pointed forward. Another claw was on the side. Troodon also had a long, stiff tail.
Birds might have come from dinosaurs such as Troodon. Many things are alike. • Troodon’s middle ear was shaped like a bird’s. • Troodon’s teeth were smaller than older dinosaurs’ teeth. Birds don’t have teeth. Small teeth could have been a step toward no teeth. • Troodon’s brain had air sacs, and so do birds’ brains. • Troodon’s wrist moved sideways, just like birds and bats move their wings.
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How Troodon Moved Troodon walked or ran on its two legs. It moved quickly to catch food. It used its big tail for balance. The tail also helped Troodon turn quickly. Troodon had a claw on each hand that was like a thumb. Troodon could use these claws to grab food. Troodon’s wrists moved sideways, unlike our wrists, which move mostly up and down. Troodon has been made into a robot. The robot’s name is Troody. It weighs 10 pounds. It is the size of a pigeon, just like a young Troodon. Sixteen electric motors move Troody’s arms and legs. Troody can run and spring. Troody helps us understand how Troodon might have moved.
14
Troodon walked on its hind legs and had claws on its feet.
Troodon had a special claw on each foot. This claw might have pulled back into Troodon’s foot, like cat claws. This probably helped Troodon run fast. Troodon could use the claw when it was needed. This claw might have helped protect Troodon, or it might have helped Troodon catch food.
15
How Troodon Moved Troodon walked or ran on its two legs. It moved quickly to catch food. It used its big tail for balance. The tail also helped Troodon turn quickly. Troodon had a claw on each hand that was like a thumb. Troodon could use these claws to grab food. Troodon’s wrists moved sideways, unlike our wrists, which move mostly up and down. Troodon has been made into a robot. The robot’s name is Troody. It weighs 10 pounds. It is the size of a pigeon, just like a young Troodon. Sixteen electric motors move Troody’s arms and legs. Troody can run and spring. Troody helps us understand how Troodon might have moved.
14
Troodon walked on its hind legs and had claws on its feet.
Troodon had a special claw on each foot. This claw might have pulled back into Troodon’s foot, like cat claws. This probably helped Troodon run fast. Troodon could use the claw when it was needed. This claw might have helped protect Troodon, or it might have helped Troodon catch food.
15
Troodon’s World Troodon lived during the Late Cretaceous Period. Pieces of Troodon have been found that are up to 75 million years old. Tyrannosaurus rex and other dinosaurs were living during the same time. Some of today’s plants were alive then. There were beech trees, fig trees, and roses. There were ferns and some grasses. There were ginko trees and cedar trees. There were oak, elm, and maple trees. There were redwood trees. All those plants were food for plant eaters. More plant eaters meant that there was more food for meat eaters to enjoy!
Troodon lived near lakes, swamps, and forests.
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Troodon’s World Troodon lived during the Late Cretaceous Period. Pieces of Troodon have been found that are up to 75 million years old. Tyrannosaurus rex and other dinosaurs were living during the same time. Some of today’s plants were alive then. There were beech trees, fig trees, and roses. There were ferns and some grasses. There were ginko trees and cedar trees. There were oak, elm, and maple trees. There were redwood trees. All those plants were food for plant eaters. More plant eaters meant that there was more food for meat eaters to enjoy!
Troodon lived near lakes, swamps, and forests.
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Troodon’s Food
Troodon’s Family Life
Most meat eaters can’t be too choosy. Troodon probably ate anything it could catch, such as lizards and snakes. Troodon also ate baby dinosaurs and dinosaur eggs. Troodon’s teeth have been found with baby hadrosaurs, which were duck-billed dinosaurs. Troodon probably also ate early mammals. There is no proof that Troodon ate plants, but Troodon did have different kinds of teeth.
Troodon laid eggs, two at a time. Scientists have found 12 pairs of long Troodon eggs together. The mother Troodon laid the eggs in a dirt nest. Scientists have also found parts of Troodon lying on top of its eggs. This tells us that Troodon parents guarded their eggs. They might have sat on the eggs to keep them warm.
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These dinosaur eggs became fossils.
19
Troodon’s Food
Troodon’s Family Life
Most meat eaters can’t be too choosy. Troodon probably ate anything it could catch, such as lizards and snakes. Troodon also ate baby dinosaurs and dinosaur eggs. Troodon’s teeth have been found with baby hadrosaurs, which were duck-billed dinosaurs. Troodon probably also ate early mammals. There is no proof that Troodon ate plants, but Troodon did have different kinds of teeth.
Troodon laid eggs, two at a time. Scientists have found 12 pairs of long Troodon eggs together. The mother Troodon laid the eggs in a dirt nest. Scientists have also found parts of Troodon lying on top of its eggs. This tells us that Troodon parents guarded their eggs. They might have sat on the eggs to keep them warm.
18
These dinosaur eggs became fossils.
19
Troodon probably stayed in family groups once their young were born. Pieces of grown and young Troodon have been found together.
20
The parents might have guarded their young, or maybe the family hunted together. Scientists uncovered fossilized Troodon eggs.
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Troodon probably stayed in family groups once their young were born. Pieces of grown and young Troodon have been found together.
20
The parents might have guarded their young, or maybe the family hunted together. Scientists uncovered fossilized Troodon eggs.
21
The End of Troodon The Cretaceous Period ended 65 million years ago. Troodon and many other animals died then. Dinosaurs were already dying out. The latest scientific thinking is that dinosaurs and other animals died from more than one cause. Here are some possibilities: • An asteroid crashed into Mexico about 65 million years ago. It caused dust to block the sun. Plants died. Because plants died, plant eaters died. Meat eaters died too, from lack of food. • Lava from volcanoes killed plants. Plant eaters died. This meant meat eaters didn’t have enough food and they died too. • Something in the air or water made some animals get sick and die. • Too many animals ate eggs. New dinosaurs didn’t get a chance to grow up. • The oceans were changing and mountains were forming. These changes wrecked the land.
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We are still learning about Troodon. Finding more clues about Troodon will help us learn more about this smart dinosaur.
Glossary asteroid (AS teh roid) — a rock in space balance (BAL uhnss) — being able to not fall over Cretaceous (kruh TAY shuhss) — period of time from 144 to 65 million years ago. Late Cretaceous Period was 89 to 65 million years ago. flesh (FLESH) — the meat of an animal lava (LAH vuh) — the hot rock that pours from a volcano mammal (MAM uhl) — a warm-blooded animal with a backbone reptile (REP tile) — a cold-blooded, air-breathing animal with a backbone that lays eggs and has skin covered with scales or bony plates sacs (SAX) — animal parts that are shaped like bags and often hold air or water wounding (WOOND ing) — hurting the skin
23
The End of Troodon The Cretaceous Period ended 65 million years ago. Troodon and many other animals died then. Dinosaurs were already dying out. The latest scientific thinking is that dinosaurs and other animals died from more than one cause. Here are some possibilities: • An asteroid crashed into Mexico about 65 million years ago. It caused dust to block the sun. Plants died. Because plants died, plant eaters died. Meat eaters died too, from lack of food. • Lava from volcanoes killed plants. Plant eaters died. This meant meat eaters didn’t have enough food and they died too. • Something in the air or water made some animals get sick and die. • Too many animals ate eggs. New dinosaurs didn’t get a chance to grow up. • The oceans were changing and mountains were forming. These changes wrecked the land.
22
We are still learning about Troodon. Finding more clues about Troodon will help us learn more about this smart dinosaur.
Glossary asteroid (AS teh roid) — a rock in space balance (BAL uhnss) — being able to not fall over Cretaceous (kruh TAY shuhss) — period of time from 144 to 65 million years ago. Late Cretaceous Period was 89 to 65 million years ago. flesh (FLESH) — the meat of an animal lava (LAH vuh) — the hot rock that pours from a volcano mammal (MAM uhl) — a warm-blooded animal with a backbone reptile (REP tile) — a cold-blooded, air-breathing animal with a backbone that lays eggs and has skin covered with scales or bony plates sacs (SAX) — animal parts that are shaped like bags and often hold air or water wounding (WOOND ing) — hurting the skin
23
Index Alaska 6 Asia 6 brain 8, 9, 12 Canada 6 Dr. Hayden 5 Dr. Leidy 5 hadrosaur 18 Montana 5, 6 scales 11 tooth 5, 9 trees 17 Tyrannosaurus rex 17
Further Reading Cohen, Daniel. Troodon. Capstone Press, 2003. Gray, Susan Heinrichs. Troodon. Child’s World, 2004.
Websites to Visit http://library.thinkquest.org/26615/troodon.htm www.enchantedlearning.com/subjects/dinosaurs/dinos/Troodon.shtml http://internt.nhm.ac.uk/jdsml/nature-online/dinodirectory/detail.dsml?Genus=Troodon
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