Animals

Dinosaurs have always been a source of interest because they are extinct and because they are so mysterious. There are many different types of dinosaurs that have been discovered, but there is always something new to learn about.

The earliest dinosaurs were beleived to be pretty small. Eoraptor was about one metre long. Its contemporary Herrerasaurus grew no more than four metres long and Coelophysis was about three metres long. And in all cases the length was mostly tail. However the plant-eating prosauropod, Plateosaurus, that appeared at the end of the Triassic period, was a harbinger of things to come. At up to nine metres long it was the first really big dinosaur.

Prosauropods could walk either on all fours or just on their hind legs, leaving their hands free, perhaps to grasp branches and bring them within reach of their mouths. They disappeared at the end of the Early Jurassic period and their role was taken by the sauropods which thrived during from the Middle Jurassic to the Early Cretaceous period.

Sauropods had huge elephantine bodies coupled with very long necks and tails. They walked only on all fours. Some such as Diplodocus could probably have reared up on their hind legs using their tails as props. Diplodocus skeletons show a number of features that support this: They have high vertebral spines over the hip region, showing the creatures had strong muscles and ligaments there. They also have skid-like bones underneath their tails, which would have protected delicate nerves and blood vessels when their tales were resting on the ground.