From the Story
"Dragons are enormous, fire-breathing creatures that can only be handled by skilled, trained wizards. Dragon breeding is not permitted in the magical world: it was outlawed by the Warlock's Convention of 1709, and dragon eggs are Class A Non-Tradeable Goods.
"Norbert the Norwegian Ridgeback is a baby dragon that Hagrid hatches from an egg that he acquired in violation of wizarding law. As a newborn, he looks like a crumpled black umbrella, and has huge, spiny wings, a skinny, jet-black body, a long snout with wide nostrils, horns and orange eyes."Within a week Norbert grows three times in length; smoke furls out of his nostrils, and he feeds on a bucket of brandy mixed with chicken blood every half hour. By the time he is two weeks old, Norbert eats dead rats by the crate, gives Ron a particularly nasty bite, and can make the walls of Hagrid's hut shake with a swing of his tail. Harry, Ron and Hermione arrange for the dragon to be collected and taken to Ron's brother Charlie, who studies dragons in Romania.
"Hagrid packs Norbert into a large crate (with his "favourite" teddy bear), and Harry and Hermione take the dragon to the tallest tower at Hogwarts, where they successfully hand him to Charlie's friends."
Discovered in Book 4, Chapter 19, The Hungarian Horntail
"The first task of the Triwizard Tournament involves four species of dragon: the Hungarian Horntail, the Chinese Fireball, the Common Welsh Green and the Swedish Short-Snout. The dragons are kept in an enclosure near the Forbidden Forest.
It is difficult to subdue a dragon, but it can be done. The dragon-keepers for the Triwizard Tournament used a Sleeping Draught to knock the dragons out on the journey to Hogwarts, and use simultaneous Stunning Spells to render them unconscious once they arrive, so they can secure their chains. A single person would be unable to knock out a dragon on their own using a Stunning Spell; dragons are strong and too powerfully magical."
Dragon parts and their uses
Dragon parts are quite useful for various purposes. Students need to purchase dragon-hide gloves for protection as part of their school attire.