The Age of Dinosaurs
230 million years ago, a group of animals called dinosaurs ruled the earth. They lived in many different habitats,
from open plains to forests to the edges of swamps, lakes, and oceans. Dinosaurs were reptiles
and most of them hatched from eggs.
Some dinosaurs were as tall as a five-storey building, and there were others no bigger than a chicken. In between the largest
and the smallest, there were dinosaurs of all shapes and sizes. The dinosaurs had tough skin covered in scales. Some were
armour-plated and covered with spikes. The name 'dinosaur' means 'most fearsome lizard'. However, dinosaurs were not lizards,
though related to them. Some scientists think that dinosaurs were more closely
related to birds.
Dinosaurs are divided into two groups:
Lizard-hipped dinosaurs. These were dominant in the Triassic and Jurassic periods.
Bird-hipped dinosaurs. These were dominant in the Cretateous period.
Dinosaurs were different from other prehistoric reptiles because of the way
they stood and walked with their bodies off the ground. Their legs were underneath their bodies rather than sticking out from
their sides like crocodiles' and turtles' legs.
Dinosaurs lived on land. No dinosaurs could fly and none lived in the water.
There were prehistoric reptiles that lived in the water, such as the Plesiosaurs (say
pless-ee-oh-saws). There were others that flew, such as the Pterodactyl (say terra-dack-till). These
reptiles were not dinosaurs, but lived at the same time.
Some dinosaurs were carnivores, which means they ate meat. They had sharp
teeth and claws. Tyrannosaurus Rex, Allosaurus and Baryonyx were carnivores.
Most dinosaurs were herbivores and ate plants. They had teeth designed to
grind their food. They had larger intestines than carnivores because plants are harder to digest than meat, so they had to
eat huge quantities. Their large heavy stomachs meant they had to walk on all fours most of the time so as not to overbalance. The largest dinosaurs
may have grown as long as 45 m and weighed as much as 77 tonnes.
Later on, some herbivores developed with their stomachs between their hind legs,
and these were able to move around on two legs. Iguanadon is one such herbivore. Other herbivores developed armour
plating and moved about on all fours, for example, Stegosaurus, Triceratops and Dyoplosaurus.
About 65 million years ago, it is believed that a huge meteor hit the earth, causing
enormous clouds of dust to block the sun's rays so that the earth became dark and cold for a number of years. Huge tidal waves
flooded low-lying land and acid rain fell. Small animals could find shelter and enough warmth and food, but the huge dinosaurs
could not. They died out. They were the most successful land animals, having existed for about 160 million years.
Click here to find out more about dinosaur groups
Click here to 'hatch' dinosaur eggs
Click here for information files about specific dinosaurs (to give an idea of dinosaur sizes,
these show an adult human beside the dinosaurs, but remember that there were no humans in the time of the dinosaurs)
Click here for information on a variety of dinosaur topics
Next, timeline of the 'Age of the Dinosaurs'
Dinosaur timeline...Fossils...Triassic...Jurassic...Cretaceous...Australian Dinosaurs...Flying reptiles...Marine reptiles...A-Z
Shauna Judith xoxo