How many years have dinosaurs existed on the earth?

Dinosaurs existed on the earth for about 65.438+0.7 billion years.

The earliest known dinosaur footprint fossils were found in some places in Europe and South America, about 240 million years ago, and all dinosaurs died out at the end of Cretaceous about 65 million years ago. The earliest age of dinosaurs was called Triassic. The Triassic weather was quite hot and dry. At that time, reptiles ruled the earth. In the middle Triassic, dinosaurs appeared. There are many kinds of dinosaurs, among which the earliest dinosaurs are Skeleton Dragon, Skeleton Plate Dragon, Ichthyosaur, Xianlong and so on.

During the Jurassic period, a variety of dinosaurs appeared, such as Lufenglong, Yunnan Dragon, Iguanodon, Liang Long, Stegosaurus, Allosaurus and so on. In Jurassic, the weather was not as dry as Triassic, and there was more rain. Many dinosaurs lived in lakes and swamps. They are also very big, usually as heavy as four or five elephants.

In the Cretaceous, great changes have taken place on the earth. The land was divided into many plates, forming oceans and land, and volcanoes on the land often erupted. Brachiosaurus, Triceratops, Diptera, Duckbilled Dragon, Tyrannosaurus Rex and Ceratosaurus appeared in this period. At the end of Cretaceous, dinosaurs became extinct.

Living habits

The plants that herbivorous dinosaurs can eat are highly restricted, so some small herbivorous dinosaurs will stand on their hind legs in order to eat the leaves of tall plants. Carnivorous dinosaurs ate herbivorous dinosaurs and other animals. Various dinosaurs' different ways of foraging will also be reflected in their teeth.

Sharp teeth and claws are hunting weapons for carnivorous dinosaurs. Tyrannosaurus rex would look for individual herbivorous dinosaurs, so they often acted alone. Some dinosaurs will move in groups, lock their prey and flock to it, and cut the abdomen of their prey with the second finger of their claws.

Herbivorous dinosaurs generally have some special "equipment" to deal with the attack of carnivorous dinosaurs. These devices are sometimes tough leather armor, bone sticks or nails, and sometimes powerful tails. Like a cudgel dragon. Large herbivorous dinosaurs will act collectively, and once threatened, they will collectively hold their ground and fight back.