Dinosaurs were recorded to be fierce and huge creatures of the past. They are considered as reptiles and feed mainly on meat and plants. Many people around the world are fascinated by these creatures. These have been featured in several movies already like the Jurassic Park.

The word dinosaur was derived from the Greek words deinos and sauros which together means terrible lizard. Dinosaurs are prehistoric animals that have existed over 200 million years ago during the Mesozoic Era. These creatures have grown in many different kinds during their existence on earth and have disappeared mysteriously during the Cretaceous Period. Based on study there are 700 types of dinosaurs which were identified but it is believed that there are more which have not yet been discovered.

Dinosaurs vary greatly in size. The smallest among the dinosaurs is the Compsognathus similar to the size with a hen only. Among the largest is the Sauropod which measures at about 100 feet in length. This type of dinosaur features a long neck known as a plant eater. Basically dinosaurs are classified according to its size and shape. Dinosaurs who feed from meet (carnivorous) are called Theropods. These are considered as bipedal animals with 3 toed feet. The Carnosaurs belong to the Theropod family which is small and is also the fastest among its kind.

Among the larger kind are the Sauropods a four legged dinosaur like the Apatosaurus Brachiosaurus and the Diplodocus. The Ankylosaurs are dinosaurs which feature spiny tails with strong armored bodies. There are also dinosaurs which have horns on top of their head like the Triceratops and are classified as Ceratopians. There are other existing animals during the Mesozoic Era that many people mistakenly identify as dinosaurs. These creatures are actually not because they dont have the same traits as the dinosaurs. Researchers have identified traits of dinosaurs.

In general however dinosaurs bear some basic traits. Dinosaurs are four legged animals but some of their kind walks on two legs. They basically dwell in land. Their bone and muscle structures are unique. They have cheek muscles which extends from the jaw connected to the skulls. Dinosaurs have a vertical gait and usually extend their bodies above their legs. Their hip girdles are composed of three bones namely pubis ilium and ischimum.

Scientists also proved that dinosaurs can run fast due to its well proportioned leg bones. They also discovered that dinosaurs have a sensitive sense of hearing and site based on the cavities that were found in their skull. Since dinosaurs are associated to be of close relationship with birds and reptiles scientist assumes that dinosaurs lay eggs. This has been proven when researchers were able to discover a fossilized egg in many different locations of the world.