Dinosaur

Dinosaurs are a group of extinct animals mentioned in the How to Train Your Dragon Book series.

Description
Dinosaurs are classified as the Clade Dinosauria, and represent a wide variety of creatures that dominated the Earth's fauna about 200 million years ago to about 66 million years ago. All dinosaurs are now extinct, though birds are thought to have evolved from a particular group of dinosaurs, and may be considered 'modern' dinosaurs. Dinosaurs are thought to be reptiles, but there is much scientific debate over this classification.

Dinosaurs encompassed both carnivores and herbivores, and creatures from the size of a chicken to those far surpassing the size of a building. There are both bipedal and quadrupedal species, as well as those that could ambulate in either stance. Many were equipped with razor sharp talons and teeth for hunting, while others were defensively equipped with spikes, horns, plates, or frills.

One specific dinosaur mentioned in the Book series is the Tyrannosaurus Rex, a large predatory bipedal creature. It is one of the more well-known species of dinosaur. It is characterized by its carnivorous nature, with up to 12 inch long teeth and its extremely short and almost vestigial arms which had only two clawed fingers.

Function
Dinosaurs mentioned in the Book series are used mostly as a comparative creature to Dragons.

In real life, while Dinosaurs are extinct, their bones are widely popular to look at and for scientific research.

How to Train Your Dragon
The Tyrannosaurus Rex is mentioned to describe the size of the Green Death, a Seadragonus Giganticus Maximus dragon.

"Imagine an animal about twenty times as large as a Tyrannosaurus Rex. More like a mountain than a living creature - a great, glistening, evil mountain."

- Book 1