The dinosaurs have always thrilled humans and held them spell bound for their variety of species from small to huge and gigantic dinosaurs. They are no more in existence but their presence is still felt in the museums, books and films. The dinosaurs first appeared on this earth around 230 million years ago and showed their existence for complete 160 million years. Some dinosaurs were herbivorous whereas some were carnivorous.

The dinosaurs existed in Triassic, Jurassic and Cretaceous period. The late Triassic period witnessed some genera of dinosaurs like Coeophysis with double hinged lower jaw and small sharp teeth showing its carnivorous nature. The one who came in the herbivorous category was the Plateosaurus with nine meter long and four meter tall body weighing about 4 tones and there were others like melanorosaurs, Anchisaur, prosauropod and early sauropod

But the end of this period witnessed mass extinction; about 95% species disappeared from this earth and with this went the early dinosaurs. The late Triassic period marked the beginning of the “age of dinosaurs" which further developed in the Jurassic Period. The Jurassic period lasted for 30 million years where reptiles were the dominant figures and so this age is known as “The age Of Dinosaurs." The dinosaurs existed during this period were different from those of other periods.

Dinosaurs evolved during this period. The largest herbivorous and carnivorous dinosaurs came into being during Jurassic period. The biggest meat eater of the Jurassic was the Allosaurus better known as the different lizard. It was about 40 feet long and many dinosaurs of this period were scared of him. Another colossal size dinosaur was a herbivore known as Apatosaurus but which was formerly known as Brontosaurus. It measured between 70 to 90 feet but its head was too small as compared to the enormous body. It is really shocking to know that on one side we had huge dinosaurs but on the other side their existed the smallest dinosaur of the size of a chicken called Compsognathus. Dinosaurs of different features and characteristics were found in this period.

Even the early known bird Archeoptyx had similar characteristics of a dinosaur. The Diplodocus dinosaur was 90 feet long and was one of the longest land animals. The long neck of Mamenchisaurus dinosaur about 46 feet was its distinctive feature which made it different from other dinosaurs. Stegosaurus existed in the late Jurassic period had a gargantuan body of three ton but the brain of the size of walnut.

The third period was the Cretaceous period when the growth of the dinosaurs was full blown. This was the time when some unique dinosaurs were there on the earth. Triceratops, Tyrannosaurus rex, Parasaurolophus, Carnotaurus Anatosaurus, Monoclonius, Tarbosaurus Gallimimus Corythosaurus, Albertosaurus, were some the dinosaurs of cretaceous Period. They were the one who came out with more distinct features and some of the exceptional characteristics which made them different from those of other period. But with the end of this period ended the existence of dinosaurs from this earth altogether.