Dinosaurs were animals that lived millions of years ago.

Many dinosaurs were very big. But some were as small as chickens are today.

Most dinosaurs ate only plants. Some dinosaurs ate other animals. They were meat eaters.

Scientists aren't sure what color dinosaurs were. Some think dinosaurs might have been as colorful as many birds are today.

In 1902, part of a huge skeleton was uncovered in Montana. Later, another was found in Wyoming. From these bones the American paleontologist Henry Fairfield Osborn drew up the first pictures of this giant creature. He named it Tyrannosaurus Rex (meaning 'king of the tyrant reptiles') because it was the biggest meat - eating dinosaur then known to have lived on Earth.

Scientists in Argentina, South America, claim to have found the world's oldest dinosaur. This creature, called Herrarasaurus, is said to be 230 million years old.

Dinosaurs sometimes had accidents, and fossil bones have been found with fractures in them.

The most complete skeleton of a Stegosaurus ever found has been dug up at the foot of the Rocky Mountains in Colorado. It had to be hauled out of the earth by an army helicopter.

Your dentist's drill has other uses. In the laboratory, scientists often use dental drills to clear and prepare dinosaur bones.

Tracks left in the mud by dinosaurs provide clues as to how quickly they moved. By measuring the distance between footprints, experts have worked out that some dinosaurs could have reached speeds up to 25 mph.

Velociraptor was probably very fierce. A fossil found in Utah, shows its claws may have been up to 15 inches in length--as long as a three-year-old child's arm. These claws formed very effective hooks with which to hold prey.

1. Some dinosaurs were as small as a hen, but the typical dinosaur weighed about as much as a hippopotamus or an elephant.

2. Dinosaur eggs are smaller than those of modern birds (relative to the weight of the mother). In fact, the largest known dinosaur eggs are much smaller than those of the extinct elephant bird of Madagascar.

3. Instead of chewing their food, some sauropods ground their food between stones in a portion of the digestive tract, much like the gizzard of a modern bird.

4. The earliest dinosaurs resembled two-legged, short-headed crocodiles, but later dinosaurs were oddly reminiscent of giant mammals and birds.

5. Some dinosaurs spent time in the water, but no dinosaur could swim very well.

6. Dinosaur bones have been found on all of the continents, but the fossil record is most complete in North America and Asia.

7. Dinosaurs had tiny (or completely absent) outside fingers and toes.

8. It's easy to tell a dinosaur skeleton from that of a modern reptile because dinosaur skeletons have a strong joint between the backbone and hips.

9. Small, two-legged dinosaurs could turn rapidly by swinging their tail abruptly in a direction opposite to where they wished to turn.

10. Some dinosaurs had feathers.

The Heaviest Dinosaur

The heaviest dinosaur was Brachiosaurus at 80 tonnes. It was the equivalent to 17 African Elephants. Brachiosaurus was 16m tall and 26m long and is the largest dinosaur skeleton to be mounted in a museum.

The Smallest Dinosaur

The smallest fully-grown fossil dinosaur is the little bird-hipped plant-eater like lesothosaurus, which was only the size of a chicken. Smaller fossilised examples have been found, but these are of baby dinosaurs.

The Most Brainy Dinosaur

One of the most intelligent dinosaurs was Troodon. It was a hunting dinosaur, about 2 metres long, and had a brain size similar to that of a mammal or bird of today, stereoscopic vision, and grasping hands

The Dumbest Dinosaur

Stegosaurus had a brain the size of a walnut - only 3 centimetres long and weighing 75 grams. However, comparing brain size to body size sauropodomorphs, like Plateosaurus, were probably one of the dumbest dinosaurs.

The Fastest Running Dinosaur

The speediest dinosaurs were the ostrich mimic ornithomimids, such as Dromiceiomimus, which could probably run at speeds of up to 60 kilometres per hour.

The Oldest Dinosaur

The oldest dinosaurs known are 230 million years old, and have been found in Madagasgar. As yet they have not been formally named. Before this Eoraptor, meaning "dawn thief" had held the title at 228 million years.

The Longest Dinosaur Name

The dinosaur with the longest name was Micropachycephalosaurus meaning "tiny thick-headed lizard". Its fossils have been found in China, and it was named in 1978 by the Chinese palaeontologist Dong.

The Fiercest Dinosaur

Tyrannosaurus rex looked the most ferocious of all the dinosaurs, but in terms of overall cunning, determination and its array of vicious weapons it was Utahraptor that was probably the fiercest of all. Utahraptor measured about 7 metres, and was a very powerful, agile and intelligent predator.

The Largest Pterosaur

Quetzalocoatlus with its wingspan of up to 13 metres was probably the largest pterosaur, and hence the largest flying creature of all time. Despite its size it weighed no more than 100 kilograms. Its only contender may be Arambourgiania, which is only known from one bone but scaled up the whole pterosaur could have been even larger. Pterosaurs were not dinosaur.

The Largest Plesiosaur

Elasmosaurus was the longest plesiosaur at up to 14 metres (46 ft) long. Half of its length was its neck, which had as many as 75 vertebrae in it (in comparison to 7-8 neck vertebrae in humans). Elasmosaurus had four long, paddle-like flippers, a tiny head, sharp teeth in strong jaws, and a pointed tail. Plesiosaurs were not dinosaurs but were marine reptiles.

What killed the dinosaurs?

It is believed that dinosaur extinction was part of a mass extinction brought about by two massive destructive events. The first of these was the collision with the Earth of a meteorite landing in what is now the Yucatan Peninsula, of Mexico. This was followed by an enormous volcanic eruption which split what is now India in half.

How many types of dinosaur were there?

At present over 700 different species of dinosaur have been identified and named. However palaeontologists believe that there are many more new and different dinosaur species still to be discovered.

The First Dinosaur to be Named

The first dinosaur to be named was Megalosaurus. It was named in 1824 by Reverend William Buckland. Megalosaurus means ‘great lizard’ and it was about 9 metres long, and 3 metres tall.

The First Dinosaur to be Discovered in America

The first discovery of dinosaur remains in North America was made in 1854 by Ferdinand Vandiveer Hayden during his exploration of the upper Missouri River. He discovered a small collection of teeth which were later described by Joseph Leidy in 1856 as belonging to Trachodon, Troodon, and Deinodon.

The Longest Dinosaur

The longest dinosaur was Seismosaurus, which measured over 40 metres, as long as five double-decker buses. It was related to diplodocus, which for a long time held the honour.

An average Tyrannosaurus Rex had arms that were only about 1 meter (3 feet) long. However, with a 1 1/2 meter jaw filled with 50 to 60 nine-inch serrated teeth, the T-Rex may not have needed to use his hands much! Bite marks on other fossils suggest that he could bite through solid bone! And if he broke a few teeth here and there, no big deal -- new ones continually grew in to replace those that he lost. Standing up to 15 meters high and weighing more than 5 tons, Tyrannosaurus Rex was massive -- but he was not the largest carnivorous dinosaur. Giganotosaurus was even bigger.

Achelosaurus Acrocanthosaurus Acrocanthosaurus Acrocanthosaurus Afrovenator Albertosaurus Albertosaurus Alectrosaurus Allosaurus Allosaurus Allosaurus Allosaurus Amargasaurus Amargasaurus Amargasaurus Amargasaurus Anatosaurus Anchiceratops Ankylosaurus Ankylosaurus Ankylosaurus Apatosaurus Apatosaurus Apatosaurus Apatosaurus Apatosaurus Argentinosaurus Archeopteryx Archeopteryx Archeopteryx Baryonyx Baryonyx Baryonyx Beipiaosaurus Belemnites Besanosaur Brachiosaurus Brachiosaurus Brachiosaurus Burgess Shale Camarasaurus Camptosaurus Carboniferous Scene Carboniferous Scene Carcharodontosaurus Carcharodontosaurus Carcharodontosaurus Carcharodontosaurus Carnotaurus Carnotaurus Carnotaurus Carnotaurus Carnotaurus Caudipteryx Caudipteryx Cearadactylus Centrosaurus Ceratosaurus Ceratosaurus Ceratosaurus Charonosaurus Chasmosaurus Chasmosaurus Chirostenotes Chirostenotes Clidastes

Coelophysis Coelophysis Compsognathus Compsognathus Compsognathus Corythosaurus Cretaceous Scene Cretaceous Scene Cretaceous Scene Cretaceous Scene Cretaceous Scene Cretoxyrhina Cryolophosaurus Cryolophosaurus Cryolophosaurus Cryolophosaurus Crytocleidus Deinonychus Deinonychus Devonian Scene Dicraesaurus Dilong Dimetrodon Dimetrodon Dimetrodon Dimetrodon Dimetrodon Dimetrodon Dimorphodon Dimorphodon Dimorphodon Diplodocus Diplodocus Diplodocus Diplodocus Diplodocus Dromaeosaurus Dromaeosaurus Dunkleosteus Dunkleostreus Einiosaurus Elasmosaurus Elasmosaurus Eotyrannus Eudimorphodon Eudimorphodon Euoplocephalus Giganotosaurus Giganotosaurus Globidens Gorgosaurus

Hadrosaur Hadrosaur Hadrosaur Helicoprion Herrerasaurus Hesperornis Hesperornis Hylaeosaurus Hypacrosaurus Hypsilophodont Huaxiagnathus Ichthyosaurus Ichthyosaurus Ichthyosaurus Ichthyosaurus Ichthyosaurus Ichtyostega Iguanodon Jobaria Jurassic Scene Jurassic Scene Jurassic Scene Jurassic Scene Leptoceratops Leptoceratops Lesothosaurus Lambeosaurus Lystrosaurus Makiakasaurus Mamenchisaurus Mamenchisaurus Mei Long Microraptor Monolophosaurus Monolophosaurus Mosasaurus Mosasaurus Mosasaurus Mosasaurus Muttaburrasaurus Nyctosaurus Ornithocheirus Orodromeus Ouranosauru •What is a Dinosaur? •93 Dinosaur Information Pages, including Apatosaurus, T. rex, Triceratops, Velociraptor, and more! •107 Dinosaur Print-outs •How Dinosaurs are Named •What Do Dinosaur Names Mean? •The Evolution of Dinosaurs •Dinosaurs and Birds •Record Breakers •Dinosaur Myths Dino News: •News Index Anatomy and Behavior: •Blood Pressure •Brains •Defense •Diet •General Anatomy •Herds and Packs •Hot or Cold Blooded? •Is it Male or Female? •Life Span •Locomotion •Offense •Reproduction, Nests, and Eggs •Size •Skeleton •Skin •Tail •Teeth The Mesozoic Era: Explore the climate, geology, and dinosaurs from these ancient times. •The Mesozoic Era ••Triassic period ••Jurassic period ••Cretaceous period •Ages of the Mesozoic Classification: •Dinosaur Classification ••Major Dinosaur Families ••Dinosaur Genera ••Saurischians - "Lizard-Hipped" Dinos ••Ornithischians - "Bird-Hipped" Dinos •What are Taxonomy and Cladistics? •Not Dinosaurs, but Old and Interesting •Dinosaur Cladogram (includes all of ornithodira) Extinction: Why did the dinosaurs go extinct? •What is Extinction? •The Alvarez Asteroid Theory •Other K-T Extinction Theories •Studying Extinctions Fossils: •First Dinosaur Fossil Discoveries •What are Fossils? •How Fossils Form •Types of Fossils •Finding Fossils •Excavating Fossils •Dating Fossils •Bony Jigsaw Puzzles •Great Fossil Hunters •Fossil Locations ••Africa ••Antarctica ••Asia ••Australia ••Europe ••North America ••Canada ••Mexico ••Official US State dinos ••South America s

Oviraptor Oviraptor Pachycephalosaurus Panoplosaurus Pachycephalosaurus Paralititan Parasaurolophus Parasaurolophus Patagosaurus Pelorosaurus Permian Scene Permian Scene Permian Scene Peteinosaurus Pisanosaurus Platecarpus Plateosaurus Plesiosaurus Plesiosaurus Plesiosaurus Plesiosaurus Plesiosaurus Plesiosaurus Pleurocoelus Pliosaur Polacanthus Protoceratops Protoceratops Psittacosaurus Pteranodon Pteranodon Pterodactyls Pterodactylus Quetzalcoatlus Rajasaurus Rhamphorhynchus Rhamphorhynchus Rutiodon Sarchosuchus Sarcosuchus Sarcosuchus Scelidosaurus Seismosaurus Seismosaurus Seismosaurus Seismosaurus Shuvuuia Silurian Scene Sinornithosaurus Sinosauropterx Sordes Spinosaurus Spinosaurus Spinosaurus Staurikosaurus Stegosaurus Stegosaurus Stegosaurus Stegosaurus Stegosaurus Stegosaurus Stegosaurus Stegosaurus Stygimoloch Stygimoloch

Struthiomimus Styracosaurus Styracosaurus Syntarsus Tapejara Tarbosaurus Tenontosaurus Tenontosaurus Thecodont Therizinosaur Therizinosaur Thespesius Titanosaurus Titanosaurus Titanosaurus Triassic Scene Triassic Scene Triceratops Triceratops Triceratops Triceratops Triceratops Triceratops Triceratops Triceratops Triceratops Troodon Tropeognathus Tuojiangosaurus Tylosaurus Tylosaurus Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Tyrannosaurus rex Velociraptor Velociraptor Velociraptor Velociraptor Velociraptor Velociraptor Xiphactinus Zallinger Mural Zuniceratops