Dinosaurs scientific name: (Dinosauria) are ancient reptiles or mammals that lived a long time ago. The name dinosaur derives from a Greek word meaning "terrifying lizard". Scientists believe that dinosaurs first appeared about 230 million years ago. 65 million years ago, dinosaurs disappeared. Birds are sometimes considered to be descendants of dinosaurs.
There are many types of dinosaurs. Today, there are about one hundred different types of dinosaurs that scientists know. There are some herbivores or eating plants, and there are carnivores or meat eaters. The largest dinosaurs, such as Apatosaurus and Brachiosaurus, are eating plants. They are the largest animals that walk on dry land.
Other dinosaurs have special weapons, which helps them fight dinosaurs. Similar to Triceratops with three horns on the face. Ankylosaurus is covered with armor. And Stegosaurus has a pointed tail. Scientists have a great idea in their minds about what these dinosaurs look like because of the bones they found.
Most meat eaters run on their toes. Some are extremely large, like Tyrannosaurus, but some are small, like Compsognathus. The smaller meat eaters are the ones who have transformed into birds. Archaeopteryx was one of the first birds, but it resembled a dinosaur.
There are large flying reptiles that also live in the presence of dinosaurs, and are called Piterosaurs or Pterosaurs, but they are not closely related to dinosaurs or birds. There are also many species of large reptiles that swim, such as Ichthyosaurs and Plesiosaur, but they are also not closely related to dinosaurs.
