Kinds of Dinosaurs

Dinosaurs ruled the earth for over 150 million years. These massive creatures evolved into many different kinds, each with its own distinct features. Suddenly, these prehistoric giants met massive extinction about 65 million years ago. Although the reason for their extinction is uncertain, scientists agree that some catastrophic event precipitated their demise. Left with only the fossils to guide them, archeologists and scientists classified dinosaurs according to common characteristics.

Classification

The primary life style of each dinosaur determined the body size and shape, making it easy for scientists to classify groups of dinosaurs by body design. Five basic body designs make up the criteria for dinosaur classification.

Sauropods

Sauropods, characterized by large barrel-shaped bodies and massive trunk-like legs with long necks and tails were herbivores feeding on plants and other vegetation. Top feeders, like the Brachiosaurus had front legs that were longer than the rear legs to raise them up to the tops of the trees. Brachiosaurus stood 40 feet tall, measured 75 feet from the tip of the nose to the tip of the tail, and weighed 89 tons. Bottom feeders like Diplodocus had longer hind legs than the front legs and were considerably shorter and longer. Diplodocus measured 86 feet long and weighed 33 tons.

Theropods

Theropods, characterized by walking on the hind legs and using the forearms for grasping, were meat eaters with razor sharp teeth. Tyrannosaurus, weighing 8 tons and standing 20 feet tall, is the most widely known of the Therapods. Surprisingly, T Rex was not a common dinosaur. Allosaurus, weighing 2 tons and standing 15 feet tall, was far more common. Raptors standing only the height of a human were extremely fast and vicious.

Ornthopods

Ornithopods, large dinosaurs with much shorter necks than the Sauropods, walked on the back legs and had chewing teeth. These dinosaurs were able to graze on grass. Iguanodons and hadrosaurs, often referred to as duck bill dinosaurs, belong to the group Ornithopods.

Armored Dinosaurs

Armored Dinosaurs, dinosaurs with bands of horn-covered plates covering the body from the neck to the tail, were also plant eaters. Stegosaurs and Ankylosaurs belong to the group called armored dinosaurs.

Horned Dinosaurs

Horned dinosaurs, characterized by a bony cape and sharp horns, were plant eaters with sharp beaks and strong grinding teeth. Triceratops belonged to the group of horned dinosaurs. Triceratops weighed up to 11 tons and measured 30 feet long. Horned dinosaurs ran on all four legs.