Dinosaur

From Simple English Wikipedia, the free encyclopedia

Dinosaurs (Dinosauria) were reptiles that lived in past times. The word "dinosaur" comes from Greek, meaning "terrible lizard". Scientists think dinosaurs first appeared about 230 million years ago. About 65 million years ago, dinosaurs became extinct. Birds are sometimes considered descendants of dinosaurs.

There were many kinds of dinosaurs. Today scientists know about hundreds of different kinds of dinosaurs. Some, called herbivores, ate plants and others, called carnivores, ate meat. The largest dinosaurs were plant-eaters, like Apatosaurus and Brachiosaurus. They were the largest animals to ever walk on dry land.

Other plant-eaters had special weapons, to help them fight off the meat-eaters. For example, Triceratops had three horns on its face, Ankylosaurus was covered in boney plates, and Stegosaurus had spikes on its tail. Scientists have a good idea of what they looked like, because of the bones that have been found.

Most meat-eaters ran around on their back legs, like people do. Some were very large, like Tyrannosaurus, and some were small, like Compsognathus. It was the smaller sized meat-eaters that may have evolved into birds. One of the first birds was Archaeopteryx, but it looked much like a dinosaur.

There were large flying reptiles that lived at the same time as dinosaurs called Pterosaurs, but they were not closely related to dinosaurs or even birds. There were also many kinds of large reptiles that could swim, like Ichthyosaurs and Plesiosaurs, but they weren't closely related to dinosaurs either.