Focus On Dinosaurs

Copyright Š 2010 Top That! Publishing plc Tide Mill Way, Woodbridge, Suffolk, IP12 1AP, UK www.topthatpublishing.com Top That! is a trademark of Top That! Publishing plc All rights reserved

CONTENTS Terrible Lizard Pages 4–6

Feeding Habits Pages 7–9

Theropods Pages 16–18

Sauropods Pages 19–20

Ornithopods Pages 26–27

Pachycephalosaurs Pages 28–30

Lifestyle Pages 10–12

Ankylosaurs Pages 21–22

Stegosaurs Pages 31–33

2

Family Trees Pages 13–15

Ceratopsians Pages 23–25

CONTENTS Coelophysis Pages 34–36

Allosaurus Pages 37–39

Tyrannosaurus rex Pages 40–41

Compsognathus Pages 42–43

Giganotosaurus Pages 44–45

Iguanodon Pages 46–47

Brachiosaurus Pages 48–49

Stegosaurus Pages 50–51

Ankylosaurus Pages 52–54

Triceratops Pages 55–57

Extinction Pages 58–60

3

TERRIBLE LIZARD Dinosaurs are among the most amazing creatures ever to have walked on Earth, and many of them looked very strange indeed. Some had spikes, some had frills and others had crests. Ever since the first remains were discovered, humans have been fascinated by these magnificent reptiles. Films have been made about dinosaurs and hundreds of books written about them.

What were dinosaurs Dinosaurs were reptiles that lived on Earth many millions of years ago. Scientists divide reptiles into groups based on the shape of their skulls. Dinosaurs belonged to the group of reptiles called diapsid.

Scientists, called palaeontologists, learn about dinosaurs by digging fossils out of the ground. When an animal dies, the bones, teeth and other pieces may become buried and preserved.

A palaeontologist at work.

When a dinosaur died...

...it eventually became buried...

Why are they called ‘dinosaurs’ When the first dinosaur fossils were found, scientists did not know what they were. They thought the fossils belonged to very large lizards. Scientists often use Greek or Latin words to describe new discoveries.

The word ‘dinosaur’ is Greek for ‘terrible lizard’.

Scientists also use Greek or Latin to name types of animal. In the case of dinosaurs, the words chosen often describe something unusual about the dinosaur’s body, the place where it was found, its behaviour or the person who discovered it.

...its flesh rotted and the bones became fossils.

4

A pterosaur in mid-flight. Pterosaurs were flying reptiles living around the time of the dinosaurs.

How many types At least 700 different types of dinosaur have been found and named, and there are probably hundreds of others that have not yet been discovered. However, scientists do not always find complete dinosaur skeletons, so it’s likely that some named as two separate species were actually the same species!

Dinosaurs came in many different shapes and sizes.

Some were as small as a modern chicken, others were larger than a bus, or even a house!

Could dinosaurs fly None of the dinosaurs that have been discovered so far were able to fly. At the time of the dinosaurs, there were flying reptiles, which looked rather like modern bats. These are known as pterosaurs, which means ‘wing reptiles’.

5

When and where did dinosaurs live Dinosaurs lived a very long time ago, during a period of time known as the Mesozoic Era. The Mesozoic Era began 245 million years ago and ended about 65 million years ago. It is divided into smaller time frames – the Triassic, Jurassic and Cretaceous Periods. At the TRIASSIC 245–208 MYA

start of the Mesozoic Era, the world’s continents were almost completely united in one piece, called Pangaea, which enabled the dinosaurs to spread throughout the world. Just think, wherever you live, the surrounding area was once home to dinosaurs!

JURASSIC 208–146 MYA

CRETACEOUS 146–65 MYA

M E S O Z O I C

E R A

How is a dinosaur special Dinosaurs are different from other reptiles in several ways. The legs of most reptiles stick out sideways from the body, whereas dinosaur legs were held directly underneath, giving them a more fluid movement. Let’s not forget their size – no mammal, including the blue whale, has ever matched them for sheer bulk.

FACT FILE There are no dinosaurs alive on Earth today.

Some films show dinosaurs fighting with humans, but this is misleading. All dinosaurs died out millions of years ago.

So far, no dinosaurs have been found that lived in the sea. There were giant sea reptiles, including plesiosaurs and ichthyosaurs, but these were not dinosaurs.

Unlike dinosaurs, the legs of most reptiles stick out to the side.

6

FEEDING HABITS Different dinosaurs ate different sorts of food. While some ate meat, others ate plants, and at least one type of dinosaur ate fish. Scientists study the fossil teeth of dinosaurs to decide what sort of food they ate.

How big were dinosaur teeth

Which dinosaur ate fish

Plant eaters often had fairly small blunt teeth for grinding leaves, while predators had razor-sharp teeth for tearing flesh.

One of the largest dinosaur teeth ever found belonged to the giant hunter Giganotosaurus – it was over 25 cm long.

Several dinosaurs had no teeth at all. Called ornithomimosaurs, which means ‘bird-like reptiles,’ these dinosaurs were named because they looked like modern ostriches. Nobody is sure what they ate – maybe fruit or insects, or some scientists think they may have eaten the eggs of other Ornithomimosaurs dinosaurs. had no teeth.

Baryonyx lived on a staple diet of fish.

Scientists found a fossilised fish inside the stomach of a Baryonyx. This shows that Baryonyx ate fish. Baryonyx teeth were long and very sharp, which made them ideal for gripping hold of slippery fish.

7

How much did dinosaurs eat Some dinosaurs ate huge meals. A giant such as Brachiosaurus might have eaten over 100 kg of food every day. This might explain the fact that scientists have found huge pieces of fossilised dinosaur excrement. Some pieces were over 50 cm long!

Generally, it was easier for dinosaurs to eat meat rather than plants. Meat could be torn up and digested easily, whereas plants had to be crushed in order to get at the nutritious parts.

Therefore, some plant-eating dinosaurs ate stones and pieces of rock, which they kept in their stomachs.

When the animal ate tough plants, the rocks would pound the food into mush, so that it could be more easily digested.

Some dinosaurs ate stones to aid digestion.

To purchase this book and others in the series, vistit www.topthatpublishing.com.