When the dinosaurs lived, the Earth's continents were

jammed together into a

supercontinent called Pangaea and

the Earth was warmer than it is

now.

Millions of years ago, long before there were no people, there were dinosaurs. Dinosaurs were one of several kinds of prehistoric reptiles that lived during the Mesozoic Era,

the "Age of Reptiles."

Dinosaurs were reptiles and most hatched from eggs. No dinosaurs could fly and none

lived in the water.

Plant-eating sauropods were the largest

animals to ever walk on

Earth!

The largest dinosaurs were over 100 feet (30 m) long

and up to 50 feet (15 m) tall (like Argentinosaurus,

Seismosaurus, Ultrasauros, Brachiosaurus, and

Supersaurus). The smallest dinosaurs, like Compsognathus, were about the size of a chicken. Most dinosaurs were in-between.

But blue whales are more massive than any of the

dinosaurs were!

It is very difficult to figure out how the dinosaurs sounded, how they behaved, how they mated, what color they were, or even how to tell whether a fossil was male or

female

No one knows what colour or patterns the dinosaurs were

Most dinosaurs were plant-eaters

(also called herbivores).

For example,Triceratops was a

plant-eating dinosaur.

Some dinosaurs were meat-eaters (also called carnivores).

For example, T. rex was a meat-eating

dinosaur.

There were lots of different kinds of dinosaurs that lived at

different times.

Some walked on two legs (they were bipedal),

some walked on four (they were quadrupedal). Some could do

both.

Some were speedy (like Velociraptor),

and some were slow and lumbering

(like Ankylosaurus).

Some were armor-plated,

some had horns, crests,

spikes,or frills

Some had thick, bumpy skin,

and some even had primitive feathers.

The dinosaurs dominated the Earth for over 165 million years during the Mesozoic Era, but mysteriously went extinct 65 million years ago. Paleontologists study their fossil remains to learn about the amazing prehistoric world of dinosaurs

The dinosaurs went extinct about 65 million years ago, at the end of the Cretaceous period, which was a time of high volcanic and tectonic activity.

There are a lot of theories why the extinction occurred. The most widely accepted theory is that an asteroid impact caused major climactic changes to which the dinosaurs couldn't adapt.

The dinosaurs went extinct 65 million years ago, probably because of the environmental changes brought about by an asteroid hitting the Earth.

Dinosaurs probably live

on today as the birds.

All that's left of the

dinosaurs are fossils

and, perhaps,the birds.

Some dinosaurs were very bird-like

and may be the ancestors of today's birds

Dinosaur fossils havebeen found all over

theworld, maybe even

near where you live!

There are almost 500 described dinosaur genera and many more species.

Every few months (sometimes weeks),

new finds are unearthed

Although dinosaurs' fossils have been known since at least 1818, the term dinosaur (deinos means

terrifying; sauros means lizard) was

coined by the English anatomist

Sir Richard Owen in 1842.

The only three dinosaurs known at the time were Megalosaurus, Iguanodon, and Hylaeosaurus, very large dinosaurs.

The oldest known dinosaur is Eoraptor, a meat-eater from about 228 million years ago.