A digital companion to Dinosaursface-offs

Learn for yourselfPaleontologists continue to find fossils, uncover facts, and develop amazing new dinosaur theories. Decide for yourself which theory is true and what could be false! Read books and articles, visit museums, and do research on the Internet with an adult. What are your theories about your favorite dinosaurs?

What would happen if you pitted the fastest, most ferocious, or largest dinosaurs against one anotherno matter when or where they lived? This digital book sets up some fantastic face-offs. Look at the facts on each dinosaur and decide who wins.

Look out for interactive buttons that light up as you roll over them. Click to discover more. Choose a dinosaur battle and follow the action.

Look for these interactive buttons:

How to use this digital book

Discover more about dinosaur features.

Close windowReturn to home screen

Blue button

Face-off facts button Encyclopedia button

Dino button

Quiz button

Questions and quizzes.

Get up close with each incredible dinosaur.

? Quick quizHOmE

Teeth

Find out what a word means.

Orange button

herbivore

Credits and acknowledgments

Cretaceous

Step into the world of the dinosaurs.

Facts and stats on each dinosaur.

Tyrannosaurus

Tyrannosaurus vs. Triceratops

Parrotlike beak

T-rex was a dinosaur; it walked on strong but skinny back legs similar to ostrich legs.

Short front limbs with claws.

Bony neck frill could reach 3 feet (1 m).

One of the largest heavyweights from the period, Tyrannosaurus rex could bite up to 500 pounds (227 kg) of meat at one time! Did vegetarian Triceratops stand a chanceeven with its three horns and protective neck plates? Look at the facts and decide for yourself.

Wh

ere din

os lived

Triceratops T. rex

Group: theropods

Lived: 7065 MYA

Diet:

Group: theropods

Lived: 6765 MYA

Diet:

Its huge 5-foot (1.5 m)head was counter-balanced by a long tail.

Its skull was 6.5 feet long (2 m).

Discover more about

Tyrannosaurus Huge and heavy, Tyrannosaurus ate large plant-eating dinos such as Triceratops. We know because fossilized T. rex dung has been found containing crushed parts of a Triceratops frill. Also, 80 bite marks found on the hip bone of a Triceratops have been identified as Tyrannosaurus bites. Was T. rex a fast, formidable hunter or a slow scavenger? Some experts think T. rex may have eaten leftovers and weak creatures it came across. It had a good sense of smell to help it track down prey or dying animals.

thats about as much as 30 male gorillas!

9 tonsA large T. rex could weigh

(8,165 kg)

The largest T. rex tooth ever found measures

1 foot(30 cm)

TriceratopsAs a plant-eater, Triceratops would have been preyed upon by the large, meat-eating dinosaurs, including Tyrannosaurus. Experts have discovered from fossil remains that Triceratops could fight back using its horns and bulk. A fossil of a Triceratops was found with a horn half bitten off, with bite marks that match a T. rexs. The horn had healed later, and that suggests that the Triceratops escaped alivethat time!

6 tonsTriceratops weighed about

(5,443 kg)

CretaceousMany dinosaurs lived during the Cretaceous period, around 14565 MYA (million years ago). The world was mostly warm, with colder periods, and large, lush forests covered much of the land. The first flowering plants appeared and spread during this time.

Increased vegetation provided food for the huge plant-eating dinosaurs, which, in turn, provided meat for the carnivores. There was also an increasing number of birds and marine animals, as well as other small land mammals. The Cretaceous period ended with the great extinction, when all the dinosaurs died out.

A map of the globe during the Cretaceous did not look the same as Earth today. At the start of the Cretaceous, some of the southern continents were still joined together, but over millions of years they eventually spread apart. The Americas gradually moved westward, causing the Atlantic Ocean to expand.

Tyrannosaurus

Biped means two-footed in Latin (from the words bi for two and ped for foot). Animals that move on their back two feet, such as birds or humans, are known as bipeds. Most animals walk on their front and hind, or back, legs, though some creatures, such as some lizards, can run on two legs for a short time. Others stand on the back two legs to reach food, keep watch, or fight.

Some dinosaurs walked on two legs, some on four. T. rex was bipedal. Triceratops walked on all fours. A few dinosaurs are thought to have reared up on their hind legs to fight or feed from leaves at the top of a tree.

Scientists think T. rex had similar legs to a modern ostrichlong and slim with strong thigh muscles to hold its body weight. Ostriches are far faster runners, up to 40 mph (64 kph), compared to a top speed of 25 mph (40 kph) for a T. rex. Some scientists think it was nearer 10 mph (16 kph).

bipedal ceratosaurus

Tyrannosaurus rexs lethal and uneven teeth were closely packed in some parts of the jaw but widely spaced in others. It had about 60 teeth, roughly the same number as albertosaurus, another large meat-eating dinosaur.

teethSharp teeth, the size and shape of bananas, poked up from the deep, 4-foot-long (1.2 m) jaws of Tyrannosaurus rex. The teeth in the upper, U-shaped jaw were larger than those in the lower, V-shaped jaw. The largest tooth found measures 12 inches (30 cm), including the root, and comes from Sue, the well-preserved 40.5-foot (12 m) T. rex skeleton on display at Chicagos Field Museum.

T. rex, like other dinosaur carnivores, did not have chewing teeth; instead its teeth had sawlike edges designed to bite and tear flesh, which was swallowed without chewing.

albertosaurus teeth

Top: albertaceratopsBottom left: pentaceratopsBottom right: Triceratops

hornsTriceratops had two long horns on its brow that reached more than 3 feet (1 m) in length, and one short, thick nose horn. Triceratops is the most famous of the great horned dinosaurs, known as ceratopsianswhich means horned-faced creatures.

Horned dinosaurs are divided into two groups. Some had large neck frills and brow horns, such as Triceratops and Pentaceratops. The others, such as Albertaceratops, had bigger nose horns and smaller, more rectangular-shaped frills with elaborate spines. They were all plant-eaters and had large, sharp beaks underneath the bottom horn.

carnivorenoun An animal that eats the flesh of other animals.car.ni.vore (kahr-nuh-vor)

herbivorenoun An animal that eats only plants. her.bi.vore (hur-buh-vor)

Guess the silhouettesMatch the dinosaur shapes to the correct names. Look in your print book and digital book for help!

Deinonychus vs. StegosaurusStegosaurus, the largest of all the plated dinosaurs, used its tail to fend off predators. How would it have fared against the fast pack hunter Deinonychus, which preyed on slow, large plant-eating dinos? The two would never have met (fossil shows they lived millions of years apart) but they would have been awesome enemies.

Its large hands had three claws.

Serrated (jagged) teeth

Its toothless beak and short front legs made the head and neck easiest to attack.

The long tail could swing from side to side.

Long, strong back legs

Wh

ere din

os lived

Group: theropodsLived: 156144 MYA

Diet: herbivore

Group:

Lived: 120110 MYA

Diet: carnivore

stegosaurusDeinonychus

Discover more about

DeinonychusDeinonychus was a fairly small dinosaur with hollow bones, but it was a light, fast, and agile runner that moved on its two back legs. Hunting in packs with other Deinonychuses, it would attack animals far larger than its own size. The dinosaur belonged to a group known as hand robbers because its hands and feet had sharp claws to snatch, hold, and eat its prey. It fought like a karate fighter, using its hands and slashing with its feet. It would also bite its victims. Many other predators used just their teeth to attack.

165 lb.the same as an average karate champ

Deinonychus weighed in at about(75 kg)

StegosaurusThis distinctive dinosaur was well protected. Its tail had fearsome spikes measuring up to 3.3 feet (1 m) to fend off attacks from behind. A blow from its powerful tail could punch a hole in the bones of a predator or knock an attacker off balance. The dinosaur had a toothless beak with small cheek teeth and may have swallowed small stones to help mash food inside its huge stomach.

30 ft. (9 m)

School bus

stegosaurus was about the length of a school bus.

stegosaurus

dino speedScientists research dinosaur speeds by comparing the prehistoric creatures to modern animals and looking at muscle size, leg structure, and weight. Some scientists think that dinosaurs that weighed less than 2,204 pounds (1,000 kg) were able to run, but that the large, heavy dinosaurs could only walk. Current research suggests that the massive dinosaurs moved at about 710 miles per hour (1116 kph). Smaller, lightweight dinosaurs such as Deinonychus that had hollow bones and long legs

would be swifter, possibly reaching speeds of 45 miles per hour (72 kph).

By investigating dinosaur footprints in hardened ground, scientists can figure out the length of a dinosaurs stridethe distance between one foot and the other as it movedand then calculate whether it was walking, trotting, or running, and its likely speed.

plateosaurus is thought to have been able to move on two or four legs. Its long, strong back legs indicate that the plant-eater could run for short bursts to escape predators.

evidencePaleontologists find fossils of dinosaur skeletons, teeth, and other body parts in rocks. They even find fossilized dino poop! Fossils give clues as to when dinosaurs lived, what they looked like and ate, and how they behaved. Ancient dinosaur tracks preserved in stretches of desert reveal how they walked and whether they moved in groups.

Footprints measuring 18 inches by 14 inches (45 cm by 35 cm) have been left in the Namib desert in Africa, along with other footprints. The tracks were made by three-toed, claw-footed animals. By measuring the depth of the footprints, scientists can estimate the size of the animals and can tell that they walked on two feet. Clear prints even show the pattern of the footpads and muscles.

LeftDinosaur tracks, millions of years old, are preserved in the Namib desert, southern Africa.

Right A dinosaur footprint in open

land near Tuba City, AZ.

stegosauruss hard plates were once thought to have been used for defense because the plates lie over the backbone and could stop a predator from biting through the spine. The jury is out as to how the plates were arranged!

bony platesTwo rows of bony plates running along the back of Stegosaurus probably helped control its body temperature, acting as miniature solar panels. Grooves found on fossils are clues that the plates were probably covered with a network of blood vessels in the dinosaurs skin. The huge plates would have been heated by the Sun, then the heat would have been transferred via blood vessels all around the dinosaur. If the animal became overheated, Stegosaurus would turn around so the thin edges of the plates faced the Sun and less heat was absorbed.

The sickle-shaped claw was held off the ground as the dinosaur moved.

clawsDeinonychus takes its name terrible claw from the huge, curved, knifelike claw rising up from the second toe of each back foot. Scientists made a model of a Deinonychus claw and it looks about as big as a childs hand4.7 inches (12 cm) long.

Deinonychus also had lethal talons on the front fingers of its huge hands. Its fingers could move so that the dinosaur could use its hands to hold on to and tear flesh from the plant-eating dinosaurs it hunted.

Curved claw

fossilizedadjective Having been made into a fossil. A fossil is a bone, shell, or other trace of an animal or plant from millions of years ago, preserved in some way, such as in rock. foss.il.ized (fah-suhl-eyez-d)

stegosaurnoun Any one of a group of herbivorous (plant-eating)dinosaurs of the Jurassic and early Cretaceous periods. They had rows of plates and spines along their backs and tails.steg.o.saur (steg-uh-sore)

Creature featuresYou can often recognize a dinosaur from just one distinctive feature. Can you name the dinosaurs from the body parts pictured here?

4

1 2

5 6

3

Giganotosaurus vs. DiplodocusOne of the longest dinosaurs, Diplodocus

had an incredibly long neck with a tiny

head. Experts wondered if this meant the

plant-eater had a tiny brain.

Would it be outsmarted by the equally hefty

(but half-the-length) giant meat-eater

Giganotosaurus? They did not live at the

same time, so your guess is probably as

good as the experts.

DiplodocusGiganotosaurus

Group:

Lived: 155145 MYA

Diet: herbivore

Group:

Diet: carnivore

Its was longer than an adult man!

Small head (compared to the size of its body!)

Diplodocuss huge size would deter most predators from attacking.

Lived: 11290 MYA

Slashing claw

Diplodocus had four large, sturdy legs.

Discover more about

Both Giganotosaurus and Diplodocus were dinosaurs.

Wh

ere din

os lived

DiplodocusDiplodocus had a large barrel-shaped body, legs like posts, a long tail raised high to counterbalance its long neck, and a very small head with rows of peglike teeth. Its lengthy neck may have been used to reach vegetation in treetops, although some experts think Diplodocus could not raise its head very high and so ate low-growing ferns or scooped up soft plants from water.

90 feet (27 m)

Diplodocus Cape Henry Lighthouse(Virginia Beach, VA)

90 feet (27 m)

Living on the floodplains found in Argentina during the Cretaceous period, the vast meat-eater Giganotosaurus was even bigger than T. rex. It probably hunted its prey on hind legs, using its jaws and claws to attack, but some research suggests that it bit its prey and waited for the victim to die. The dino may have sometimes hunted in packs to attack huge dinosaurs. Fossils of the largest plant-eating dinosaur to have lived, the 75-foot-long (23 m) Argentinosaurus, have been found near it.

Big awards

Giganotosaurus was longer and heavier than T. rex, but the award for the largest meat-eating dino goes to Spinosaurus.

Spinosaurus

Giganotosaurus T. Rex

Giganotosaurus

JurassicThe Jurassic period began around 199 million years ago at the end of the Triassic period and ended with the beginning of the Cretaceous period, 145 million years ago. Many dinosaur fossils have been uncovered in thick layers of sandstone dating back to the Jurassic period, especially in the western United States at the border of Colorado and Utah, where Dinosaur National Monument now covers more than 210,000 acres (85,000 hectares).

Sea levels were high in the late Jurassic period and the climate became warmer and more moist. More vegetation grew, which meant more food for dinosaurs, which increased the population and brought about new species.

During the Jurassic period, the landmasses of Earth were not the same as they are today. The continents as we know them were only just beginning to form as seas began to flow between landmasses. North America, Europe, and Asia were formed to the north in Jurassic times. The south was a single landmass known as Gondwanaland.

Gondwanaland

North America

lizard-hippedDinosaurs are divided into two main groups bird-hipped and lizard-hipped dinosaurs. Lizard-hipped dinosaurs are known as saurischians (so-ris-key-ins). All the meat-eaters that mainly walked on their back feet (theropods) were lizard-hipped dinosaurs, as were the massive plant-eaters (sauropods), such as Diplodocus, Camarasaurus, and Argentinosaurus. The hips of saurischians look the same as those of modern lizards. Basically, the pubis bone (the lower bone of the hips) points down and forward in the saurischians. In bird-hipped dinosaurs, the pubis points backward.

The mega meat-eating Tyrannosaurus rex was a lizard-hipped dinosaur.Pubis bone

A copy of a Giganotosaurus skull found in Patagonia, Argentina.

skull Giganotosaurus had the longest skull ever found of any meat-eating dinosaur, measuring up to a massive 6 feet, 5 inches (1.96 m) in length. Although the dinosaur was larger than T. rex, its skull was slimmer than a T. rex skull. Giganotosaurus is also thought to have had a small brainabout half the size of T. rexs and shaped like a banana or cucumber.

Giganotosaurus had a long jaw with shorter and narrower teeth than T. rexs. These would have been used to slice flesh rather than bite off chunks.

Diplodocus (pictured) was not the only large, long-necked, plant-eating dinosaur. Others include Brachiosaurus, Apatosaurus, Vulcanodon, Seismosaurus, and Plateosaurus.

long neck An adult Diplodocus had a lengthy neck reaching up to 26 feet (8 m). Fossils show it had around 15 neck bones along its length, compared to the seven in humans and most other mammals, including the giraffe.

The vertebrae (back and neck bones) would have been held in place by ligaments, which are strong tissues. Scientists think that ligaments would have run from the back of the neck right down to the dinosaurs hip, to let Diplodocus hold its neck in a horizontal position.

sauropod noun Any one of a group of huge herbivorous (plant-eating) dinosaurs that walked on four legs and were lizard-hipped. Most had long necks and tails.sau.ro.pod (sore-uh-pod)

theropodnoun Any one of a group of carnivorous (meat-eating) dinosaurs that walked on two feet and had small front limbs. Theropod means beast-footed. the.ro.pod (thir-uh-pod)

Digging dinosThere is a lot of guesswork in putting together dinosaur bones! Can you figure out which bones belong to the two-legged meat-eater and which to the four-legged veggie-eater?

4

1 2

5 6

3

Allosaurus was the most common predator of the late Jurassic. The massive meat-eater with the huge jaw appeared after the man-sized Herrerasaurus had died out. Would a group of the fierce, fast with vicious claws have been a match for Allosaurus and its sawlike teeth?

Herrerasaurus vs. Allosaurus

Wh

ere din

os lived

herrerasaurus allosaurus

Group: theropods

Group: theropods

Lived: 228 MYA

Lived: 153135 MYA

Allosaurus had backward-curving 24-inch (510 cm) teeth for tearing flesh.

Diet: carnivore

Sharp teeth had serrated (jagged) edges.

Large and powerful back limbs carried the bulky dinosaur upright.

Discover more about

Diet: carnivore

Short front limbs had five-fingered hands with three claws.

AllosaurusPowerfully built, Allosaurus was one of the

largest carnivores of the Jurassic period.

It walked on two feet with its stiff tail raised

to keep it from falling over. The fingers of

the dinosaurs short, muscular arms ended

in large claws. Its teeth curved backward

so, once bitten, prey could not escape.

Allosaurus had flexible joints in its skull

and jaw so it could tear off huge chunks

of meat from its large victims, including

Camarasaurus.

At 16 ft., 4 in. highallosaurus was more than twice as tall as the tallest NBA basketball player

16 ft., 4 in. (5 m)

7 ft., 6 in. (2.29 m)

(5 m)

27 mph;herrerasaurus could probably run

(43 kph)

thats a 100-meter race run in 8.37 seconds

faster than an Olympic sprinter

HerrerasaurusOne of the earliest dinosaurs to have lived, Herrerasaurus was named for the man who first found its fossils in 1959, Victorino Herrera. Agile and fast, Herrerasaurus was also one of the first to have walked on two feet. Its front limbs were much shorter than its back legs, and the long thumb and first two fingers had curved claws, which were probably used to seize prey. It also had claws on its back feet.

TriassicThe first dinosaurs appeared on Earth about 228 million years ago, toward the end of the Triassic period. The Triassic period lasted for about 52 million years, from around 251 to 199 million years ago, ending as the Jurassic period began.

During the Triassic period, some areas of Earth were hot and dry but others had monsoons (violent downpours of rain). Stretches of land were covered with swampswetlands with trees, ferns, and rushes. The first appeared in the late Triassic (from 215 million years ago) when there were many small and medium-sized animals. The largest animals at the time were marine reptiles that lived in the sea. This was not a period of huge dinosaursmost were around 1015 feet (34.6 m) long.

At the start of the Triassic period our planet looked very different. All of the landmasses had drifted together to form one single great continent known as Pangaea. Gradually the areas of land began to break apart and mountains began to form.

pack huntersSome dinosaurs are thought to have hunted together in groups, known as packs, just as many animals do today, including wolves, lions, and even ants. Hunting in packs allows an animal to tackle prey that is larger than itself.

Pack hunters would only hunt with other members of their own species. Working together, smaller predators, such as Herrerasaurus or Deinonychus, could kill a large animal. Fossils of several small Deinonychus dinosaurs have been found together around one large herbivorous(plant-eating) dinosaur, Tenontosaurus. Larger dinosaurs, such as Allosaurus, may also have hunted in small groups to allow them to kill and eat the gigantic herbivorous dinosaur Apatosaurus.

A pack of Monolophosaurus dinosaurs (found in China) are pictured attacking a lone horned Einiosaurus.

allosaurus had a ridge of bone running along both sides of its nose, leading up to the eyes, as well as a brow ridge jutting out above each eye.

brow crest Brow crests (also known as brow horns) were large bumps of bone or horn that stuck out above a dinosaurs eyes. Allosaurus had a large, rough, triangle-shaped horny crest over each eye. Scientists think these bony ridges protected the eyes when the large predator attacked its victims. They may also have been used to attract another Allosaurus as a mate.

herrerasauruss long tail was stiffened in parts by overlapping sections of bone so that the dinosaurs body was balanced and it could run quickly.

tail for balanceDinosaurs that walked on their two back feet (known as bipeds), such as Herrerasaurus and Allosaurus, used their tails as a counterbalance to stop them from toppling over. Meat-eating dinosaurs, including the massive Allosaurus and T. rex, carried their large bodies more horizontally rather than upright, as though leaning forward. Their front limbs were too tiny to reach the floor to steady them. The long, stiff, and heavy tails poking out behind the dinosaurs were essential for keeping their weight in the center.

mammalnoun A warm-blooded animal that has hair or fur and usually gives birth to live babies. Female mammals produce milk to feed their young.mam.mal (mam-uhl)

Whos at the end of the tail?Can you match the tails to the dinosaurs? One dinosaurs tail isnt picturedwhich is the odd one out? Hunt in your print book and digital book for help!

Diplodocus

stegosaurus

Velociraptor

Dromaeosaurus

ankylosaurus

Discover more about

Dromaeosaurus vs. Edmontosaurus With no sharp, biting teeth or horns to defend itself, Edmontosaurus would be easy prey for many of the big meat-eaters of the Cretaceous period. The plant-eater was many times the weight of the small, speedy Dromaeosaurus. think that Dromaeosaurus hunted in packs. Even so, would a group be able to pick off and overpower a hefty Edmontosaurus?

Group: theropods

Group:

Lived: 7674 MYA

Lived: 7665 MYA

Diet: carnivore

Diet: herbivore

Dromaeosaurus had big eyes.

The large, toe claws didnt touch the ground and so stayed sharp.

Edmontosaurus was a dinosaur.

Wh

ere din

os lived

Dromaeosaurus edmontosaurus

Edmontosaurus lived with others in a herd for safety.

DromaeosaurusAlthough small, Dromaeosaurus is thought to have been clever, and it had a big brain compared to many dinosaurs. It had razor-sharp, backward-curving teeth and powerful jaws used for crushing and tearing. Experts think Dromaeosaurus may have had a bite nearly three times as powerful as that of Velociraptor. The meat-eater also had 3-inch (7.6 cm) claws like an eagles used for kicking prey, on the second toe of each back foot.

it was the length of a lioness or wolf

At 6 feet(1.8 m)

Dromaeosaurus lioness wolf

1,000edmontosaurus had

grinding teeth in its cheeks. More than 31 times the teeth you have!

This large duck-billed herbivore had strong back legs. Scientists think it walked on four legs most of the time but could also move on two legs, lifting itself up on its back legs for bursts of speed or to reach into trees for food. Twigs, seeds, fruit, and even hard conifer needles have been found inside its stomach fossils. It had no natural weapons; instead it lived in a herd for defense and ran to escape predators.

Edmontosaurus

How individual types of dinosaurs get their names often depends on who found them and where. Edmontosaurus takes its name from the area of Alberta, Canada, where its fossils were found, which at that time was known as the lower Edmonton Formation. Some dinosaurs are named for or by the person who discovered them. Herrerasaurus means Herreras lizard because of the rancher who first found its fossils; and Timimus gets its name from two paleontologists named Tim.

The term Dinosauria was coined in 1842 by Richard Owen, an English scientist. Owen said that he made up the name from the Greek words meaning fearfully great lizards. We now know that not all dinosaurs were fearfully largesome dinosaurs were quite smallbut we know the ancient creatures as dinosaurs thanks to Owen.

Richard Owen was a naturalistan expert in natural history. He was born in Lancaster, Great Britain, in 1804, and lived until 1892.

naming dinosaurs

bird-hippedDinosaurs are divided into two main groups: bird-hipped, or ornithischian (or-nuh-this-key-in), dinosaurs; or lizard-hipped, or saurischian (so-ris-key-in), dinosaurs. Bird-hipped dinosaurs have similar hips to those of modern birds. The lower bone of the hips, called the pubis, points backward, toward the tail of the animal, behind the creatures back legs. (In lizard-hipped dinosaurs, the pubis points forward.)

All of the bird-hipped dinosaurs were plant-eaters. And, interestingly, although the hips of modern birds are like those of ornithischian dinosaurs, birds did not descend from them; instead it is the lizard-hipped dinosaurs that were the ancestors of modern birds.

A re-creation of a skeleton of a Stegosaurus, a bird-hipped dinosaur. Each hip is made up of three pairs of bones: the ilium, ischium, and pubis. It is the lower pair of bones, the pubis, that points in different directions in the two types of dinosaurs.

IliumIschium

Pubis

Preserved imprints of edmontosaurus skin have been found in North Dakota.

scaly skinIt is very rare to find fossilized dinosaur skin, since soft tissue does not preserve like hard tissue (bone and teeth) does. But samples of skin of an Edmontosaurus have been found. From the imprints dried in mud, scientists can tell us the texture of Edmontosauruss skin. The imprints show that the dinosaurs skin was scaly, hard, and leathery and had bumps along the back. The color is unknown.

edmontosauruss jaws could move slightly from side to side. Scientists think that it chewed its food by sliding its top teeth sideways across the bottom teeth to grind and shred the plants it ate.

duck-billedEdmontosaurus was a hadrosaur, or duck-billed dinosaur, which meant it had a beak like a ducks. All hadrosaurs had a broad, toothless horny bill. However, they could have hundreds of sharp teeth set further back in the cheek area of their upper and lower jaws. These were used for chewing, grinding, and shredding tough plants before they were swallowed.

retractableadjective Able to be drawn back. A retractable claw can be extended when necessary and then withdrawn when no longer needed. Cats have fully retractable clawstheir claws can be pulled back into the paws when not in use. A dinosaur claw was only pulled back away from the ground. re.tract.a.ble (ree-trak-tuh-buhl)

paleontologistnoun A scientist who studies plants and animals that lived in ancient times.pa.le.on.tol.o.gist (pay-lee-on-tah-luh-jist)

ornithopod noun Any one of a group of herbivorous (plant-eating), bird-hipped dinosaurs. Some had bony plates, or armor, on their back. or.nith.o.pod (or-ni-thuh-pod)

allosaurus

Gallimimus

Trodon

Brachiosaurus

Baryonyx

Velociraptor

The name gameCan you match each dinosaur to the correct meaning of its name?

Copyright 2012 by Scholastic Inc.

All rights reserved. Published by Scholastic Inc.,Publishers since 1920. scholastic, scholastic discover more tm, and associated logos are trademarks and/or registered trademarks of Scholastic Inc.

All rights reserved under International and Pan-American Copyright Conventions. No part of this publication may be reproduced, transmitted, downloaded, decompiled, reverse engineered, or stored in or introduced into any information storage and retrieval system, in any form or by any means, whether electronic or mechanical, now known or hereinafter invented, without the express written permission of the publisher. For information regarding permission, write to Scholastic Inc., Attention: Permissions Department, 557 Broadway, New York, NY 10012.

Library of Congress Cataloging-in-Publication Data Available

ISBN 978-0-545-36572-7

First edition, September 2012

Scholastic is constantly working to lessen the environmental impact of our manufacturing processes. To view our industry- leading paper procurement policy, visit www.scholastic.com/ paperpolicy.

Consultant: Kim Dennis-Bryan, PhDSenior Editor: Jayne MillerSenior Art Editor: Yumiko TahataInteractive Designer: Penny LamprellVisual Content Project Manager: Diane Allford-Trotman

Image creditsTitle screen: (tl) Ajtooley/Dreamstime; (background, tr) Aliencat/Dreamstime; (skull icon br) iStockphoto. Contents: (scaly background) iStockphoto; (grid background) Maninblack/Dreamstime; (tr) Ralf Juergen Kraft/Shutterstock; (computer icon cr) Vector/Shutterstock. How to use:

(background) TommL/iStockphoto; (Tyrannosaurus silhouette) iStockphoto; (Triceratops silhouette) pixel-shack.com; (Gallimimus silhouette, Stegosaurus silhouette) Thinkstock. Tyrannosaurus vs. Triceratops: (metal texture on buttons, map) iStockphoto; (Tyrannosaurus, Triceratops, background, Tyrannosaurus button, Triceratops button, Tyrannosaurus silhouette) iStockphoto; (Triceratops silhouette) Thinkstock. Cretaceous: (l) Walter Myers/Photo Researchers, Inc.; (map) iStockphoto. Teeth: (l) Linda Bucklin/iStockphoto; (br) Wesley Pohl/iStockphoto. Horns: (t) Aliencat/Dreamstime; (bl) Mr1805/Dreamstime; (bc) pixel-shack.com. Bipedal: (tl) Kostyantyn Ivanyshen/Shutterstock; (bl) Allan Tooley/iStockphoto; (bc) Nikola Miljkovic/iStockphoto. Tyrannosaurus: (gorilla) Douglas Bray/iStockphoto; (r) iStockphoto. Triceratops: (Tyrannosaurus silhouette) iStockphoto; (scale) liangpv/iStockphoto; (car) Jonathan Haste/iStockphoto; (r) pixel-shack.com. Tyrannosaurus vs. Triceratops quiz: (tl) iStockphoto; (cl, bl) Thinkstock; (tr) VectorWeb/Shutterstock; (cr) Thinkstock; (br) Zobeedy/Dreamstime; (correct answer audio) Marbury/iStockaudio; (incorrect answer audio) DarylFX/iStockaudio. Deinonychus vs. Stegosaurus: (r) pixel-shack.com; (Deinonychus button) Ralf Kraft/Dreamstime; (Stegosaurus button) pixel-shack.com; (Deinonychus silhouette) Zobeedy/Dreamstime; (Stegosaurus silhouette) Thinkstock. Evidence: (l) Peterhulla/Dreamstime; (br) Mark Higgins/Dreamstime. Bony plates: pixel-shack.com. Claw: Ralf Kraft/Dreamstime. Dino speed: Michael Rosskothen/Shutterstock. Deinonychus: Louie Psihoyos/Getty Images. Stegosaurus: (bus) iStockphoto; (Stegosaurus silhouette, r) pixel-shack.com. Deinonychus vs. Stegosaurus quiz: (tl) pixel-shack.com; (tc) Ralf Kraft/Dreamstime; (tr) iStockphoto; (bl) Kostyantyn Ivanyshen/Shutterstock; (bc) Hemera/Thinkstock; (br) Catmando/Shutterstock. Giganotosaurus vs. Diplodocus: (r) pixel-shack.com; (Giganotosaurus button) leonello calvetti/Shutterstock; (Diplodocus button) pixel-shack.com; (Giganotosaurus silhouette) Victor Habbick/Dreamstime; (Diplodocus silhouette) pixel-shack.com. Jurassic: (l) Computer Earth/Shutterstock; (map) Mikkel Juul Jensen/Bonnier Publications/Photo Researchers, Inc. Long neck: Mr1805/Dreamstime. Skull: Kabacchi/Wikimedia Commons. Lizard-hipped:

iStockphoto. Giganotosaurus: (trophies) Oleksiy Mark/iStockphoto; (ribbon) koksharov dmitry/iStockphoto; (r) Michael Rosskothen. Diplodocus: (Diplodocus silhouette) Hemera/Thinkstock; (lighthouse) Scholastic; (r) Catmando/Shutterstock. Giganotosaurus vs. Diplodocus quiz: (background) Linda Bucklin/Shutterstock; (tl) ags1973/iStockphoto; (tc) breckeni/iStockphoto; (tr) Linda Bucklin/iStockphoto; (bl) breckeni/iStockphoto; (bc) Linda Bucklin/Shutterstock; (br) breckeni/iStockphoto. Herrerasaurus vs. Allosaurus: (r, Herrerasaurus button, Allosaurus button, Herrerasaurus silhouette, Allosaurus silhouette) pixel-shack.com. Pack hunters: DM7/Shutterstock. Brow crest: Thinkstock. Tail for balance: pixel-shack.com. Triassic: (l) Photo Researchers, Inc.; (map) iStockphoto. Herrerasaurus: (bl) Pete Saloutos/iStockphoto; (r) pixel-shack.com. Allosaurus: (basketball player, hoop) A-Digit/iStockphoto; (Allosaurus silhouette) pixel-shack.com; (r) Image Source/Alamy. Herrerasaurus vs. Allosaurus quiz: (tl) Linda Bucklin/Shutterstock; (bl, tc, bc, Diplodocus) pixel-shack.com; (Velociraptor) Ralf Kraft/Dreamstime; (Dromaeosaurus, Ankylosaurus, Stegosaurus) pixel-shack.com. Dromaeosaurus vs. Edmontosaurus: (r, Dromaeosaurus button, Edmontosaurus button) pixel-shack.com; (Dromaeosaurus silhouette) Scholastic; (Edmontosaurus silhouette) pixel-shack.com. Scaly skin: pixel-shack.com. Bird-hipped: Linda Bucklin/iStockphoto. Duck-billed: pixel-shack.com. Naming dinosaurs: public domain. Dromaeosaurus: (Dromaeosaurus silhouette) Scholastic; (lioness) cenker atila/Shutterstock; (wolf) Igor Djurovic/iStockphoto; (r) pixel-shack.com; (r background) Radius Images/Corbis. Edmontosaurus: (r) leonello calvetti/Shutterstock; (r background) iStockphoto. Dromaeosaurus vs. Edmontosaurus quiz: (tl) pixel-shack.com; (cl) Thinkstock; (bl) Scholastic; (tr) Shutterstock; (cr, br) Viktorya170377/Shutterstock.

Many thanks to Grolier Onlinetm for articles and assistance.

Credits

Button 249: Button 253: Button 251: Button 254: Button 252: Button 250: Button 106: Button 49: Button 50: Button 63: Button 64: Button 65: Button 66: Button 67: Button 1010: Button 68: Button 70: Button 71: Button 72: Button 73: stats 1: Button 107: Button 105: Button 74: Button 271: Button 77: Button 78: Button 79: Button 80: Button 103: Button 81: Button 82: Button 83: Button 84: Button 85: Button 86: Button 87: Button 88: Button 89: Button 90: Button 91: Button 92: Button 93: Button 94: Button 95: Button 96: Button 97: Button 98: Button 267: tip: Button 108: Button 1011: Button 1019: Button 100: Button 101: Button 104: Button 109: Button 110: Button 111: deinony stats: Button 219: Button 1012: Button 1013: Button 112: Button 113: Button 114: Button 115: Button 116: Button 117: Button 118: Button 1014: Button 120: Button 121: Button 122: Button 123: Button 124: Button 125: Button 126: Button 127: Button 128: Button 129: Button 130: Button 131: tip2: Button 268: Button 132: Button 133: Button 134: Button 135: Button 136: Button 1015: Button 138: Button 139: Button 140: Button 141: gig stats: Button 236: Button 1016: Button 1017: Button 142: Button 1018: Button 143: Button 144: Button 145: Button 146: tip3: Button 148: Button 149: Button 150: Button 151: Button 152: Button 153: Button 154: Button 155: Button 156: Button 157: Button 158: Button 159: Button 1020: Button 269: herr stats: Button 221: Button 223: Button 224: Button 225: Button 226: Button 227: Button 228: Button 229: Button 255: Button 1021: Button 1022: Button 230: Button 231: Button 232: Button 233: Button 234: Button 235: Button 237: Button 238: Button 239: Button 240: Button 241: Button 242: Button 243: Button 244: Button 245: Button 246: Button 247: Button 248: Button 270: Button 1023: Button 274: Button 189: Button 190: Button 191: Button 193: Button 194: Button 195: Button 196: Button 1024: Button 197: Button 198: Button 199: Button 264: Button 256: Button 1025: Button 1026: Button 200: Button 201: Button 202: Button 203: Button 204: Button 205: Button 206: Button 1027: Button 207: Button 1028: Button 208: Button 209: Button 210: Button 211: Button 212: Button 213: Button 1029: Button 214: Button 215: Button 216: Button 1030: Button 1031: Button 217: Button 218: Button 1032: Button 1033: Button 2010: tip5: Button 220: