The World of Dinosaurs

Imagine a world with no people in it. No cars, no cities, not a single house. Just jungle, forests, and enormous animals roaming a landscape that almost nobody has ever seen. This is not a fantasy world, this is our Earth, more than sixty million years ago. Welcome to the age of the dinosaurs!

Dinosaurs lived for an enormously long time, actually much longer than we can really imagine. They appeared about two hundred and fifty million years ago and kept going for nearly one hundred and eighty million years. If Earth's entire history were a single day of twenty-four hours, dinosaurs would have ruled for more than four whole hours. Humanity? We have only been here for the very last seconds. That is a dizzying thought.

Let us start with one of the most astonishing dinosaurs that ever lived, Argentinosaurus. It was a plant-eating animal that was probably one of the heaviest land animals that has ever existed. It was as long as four school buses lined up in a row. It is estimated to have weighed more than ten fully grown elephants put together. Every step it took shook the ground. Imagine seeing an animal like that, standing as tall as a five-storey building!

But not all dinosaurs were peaceful plant-eaters. The most famous of all is Tyrannosaurus rex, or T. rex as we usually call it. T. rex was the most powerful hunter of its time. It was roughly as long as a bus, ten metres from head to tail, and walked upright on its powerful back legs. Its head was enormous, almost as big as a grown person is tall. And inside that head were some of the meatiest teeth any animal has ever had.

T. rex had a bite stronger than almost any other animal. Its teeth were nearly thirty centimetres long, about as long as your forearm! But T. rex also had a funny little mystery: its arms were incredibly short and weak. Why did the greatest hunter of its time have such tiny arms? Scientists honestly do not know for certain. One theory is that they were useful for getting up from a lying position. Another is that they helped during mating. But just like so much else about dinosaurs, we are not entirely sure.