- "Never laugh at live dragons, Bilbo you fool! You aren't nearly through this adventure yet."
- —Bilbo Baggins to himself 
Dragons were ancient, powerful creatures, as feared by others as they were admired in Middle-earth. They were powerful and intelligent. Their exact origin is debated, though it was clearly stated that they were created by Morgoth in some sense.
Dragons lived throughout the First, Second, and Third ages of Middle-earth and may have lived longer. They were originally bred by Morgoth during the first age to serve as gigantic shock troopers and mobile artillery. The first dragon ever seen in Middle-earth was Glaurung, the father of dragons, who Morgoth used to great effect during the third and fourth battles in the War of the Jewels. Like most of the creatures made or twisted by Morgoth, they were capable of reproducing naturally. Dragons were sometimes referred to as serpents, great Worms, or simply Drakes, with the first two specifying the Wingless Dragons.
During the First Age, the greatest heirloom of the house of Hador was the Dragon-helm of Dor-lómin, which was a helm of great weight that had as its crest an image of the head of Glaurung the Dragon. 
The dragons of the Second Age and Third Age were a blight on the Dwarves and all those who hoarded treasures. Some, like Smaug the Golden and Scatha the Worm went from the Withered Heath and invaded Dwarven kingdoms. There had not been notable activities observed during the Second Age, but dragons seemingly kept serving as dark servants (partially at least).
It is presumed that after the death of Smaug in the Third Age the great dragons had gone extinct. According to Gandalf, the fire-drake race was surviving until at least just before the War of the Ring, and some lesser kin survived even after the war. It may have been possible that some races of dragon still existed throughout the Fourth Age.
Types of Dragons
The taxonomic system for Dragons in Middle-earth is based on two factors: means of locomotion, and fire breathing.
- Fire. Depending on whether a Dragon can breathe fire, it might be termed
- Stone Dragons - almost nothing is known about biology of this breed.
- Means of locomotion
- Winged Dragons - Dragons that had four legs but also wings which enabled them to fly.
- Wingless Dragons - Dragons with no wings that walked on four legs. Spark-dragons are possibly categorized in this group.
- Serpent-like Dragons - Dragons with no legs and no wings, such as the Wyrms/Long-worms (and perhaps the Sea-serpents).
Some Dragons could not breathe fire and were known as Cold-drakes. Of these most could not breathe anything at all, but some few could breathe a smoke or vapor or mist. In particular many Dragons without legs or wings were Cold-drakes. Cold-drakes are not referred to until the Third Age, though that does not mean they did not exist before. Possibly some Dragons, or perhaps some of their descendants, lost the ability to breathe fire in the millennium after the War of Wrath.
In addition to being long-lived, powerful, and cunning, dragons also possessed subtle intelligence, great physical strength, and nearly impenetrable scales on everything but their undersides. They also posessed an overwhelming greed for treasure, especially gold. Dragons were well known for sleeping on piles of stolen treasure. By their very nature, it was desirable to them to not only steal beautiful things, but to relish the act of dispossessing those from whom they took such property. According to Thorin Oakenshield they had a very keen sense of the value of their hoard, but never themselves crafted so much as a brass ring. Dragons were prone to anger, and such fits of rage that towns, countrysides, and certainly individuals close at hand were subject to violent cataclysms of fire and destruction. The reasons for their strong affinity for gold are unknown, but dragons often put more of a priority on gold than food, and they can survive not eating (and maybe drinking as well) for tens or hundreds of years, and this suggests that jewels are indeed primal sources of the great serpents' life forces. Due to this fact, dragons of Arda may or may not be immortal in ideal conditions (they live very long anyway).
They also had a hypnotic power called "dragon-spell"; weaker-willed beings could be put into a trance or bent to a dragon's will when the beast spoke. Even those of strong will could be subjected to this ability, especially if they were not prepared. Dragons could make even greater use of this ability through psychological manipulation, increasing the power of the spell by taunting a subject with some inner conflict. Glaurung, for instance, was not fully capable of bending Túrin to his will, but when the dragon began to taunt him with his own failings, Túrin became far more receptive to the dragon's suggestions. In addition, this dragon-spell seems to have had the ability to plant mistrust in the listener's mind. This power also extended to a dragon's treasure hoard, causing it to excite feelings of greed and animosity among others who would possess it. Feuds and battles frequently followed upon the death of a dragon; usually between the individual who slew the beast and the original owners (or their heirs) of its hoard, as well as an occasional ambitious third party. Some have speculated that this 'curse' played a part in Fram's death at the hands of the Dwarves after he had slain Scatha. The same could be said of the famous Battle of Five Armies upon the death of Smaug.
All accounts of interaction between dragons and other beings makes mention of them speaking, using the Common Tongue. Those unfortunate episodes usually culminated in the dragon manipulating the individual to believe things either false, or in the worst possible light. These creatures evidently delighted in sowing discord and strife among others, which is reflective of their nature. Dragons apparently had a love of riddles and puzzling talk, spending long hours trying to decipher it. Therefore, speaking in ambiguous riddles was the best way to converse with a dragon, as it was quite unwise to either tell the full truth or to directly refuse them.
Dragons had an acute sense of smell. During his encounter with Smaug, Bilbo Baggins was informed in no uncertain terms that (even though the dragon could not determine what manner of creature he was) he knew that he was in the company of Dwarves due to the scent of a "dwarf-ridden pony". Furthermore, despite his invisibility, thanks to the One Ring, Smaug was aware of the hobbit's presence by both his breath, and the movement of the air he caused in the great hall. Dragons were known to be able to sleep with half an eye open, on the alert for intruders if they were suspicious. The hobbit, his senses perhaps heightened by wearing the ring, also reported seeing a pale ray of light eminating from Smaug's eye as he probed the chamber back and forth for the burglar.
Dragons had strong scales, which could resist most weapons, though young dragons had to grow into their natural armour. Mithril is said to have been as strong as dragon scales, though lighter in weight. The underbelly of a dragon was described as soft, slimy, and unarmored; however, Smaug from The Hobbit, had lain so long on the heap of treasure in the deep of the Lonely Mountain that gems and coins had become encrusted in the slime, so that he was "armored above and below with iron scales and hard gems"; he was also said to have had scales there too making his underbelly harder to strike at than his back. The Dwarves appear to have had some skill at fighting dragons, as seen when they held off Glaurung for a time in the Nirnaeth Arnoediad. This was one of the few instances where the battle was not due to stolen gold. The age-old fight between dwarves and dragons was primarily a result of the dwarves placing great value on their hard-earned treasure, and the dragon's habit of stealing it. King Dain I and his son Fror of the Grey Mountains were both slain at the doors of their hall by a great cold-drake. Both races had a lust for beautiful metals and gems, and so, naturally, came into conflict, with the dragons generally prevailling.
A great stench went before Glaurung, and his blood contained some sort of venom, though it is not known if all dragons had these two traits, although the Dwarves commented on the reek of Smaug that filled the Lonely Mountain's halls after the dragon's long stay there.
Dragon fire was hot enough to melt the Rings of Power. Indeed, four of the seven rings gifted to the Dwarves were consumed by dragon fire. However, it was said by Gandalf that no dragon's fire would be hot enough to melt the One Ring, not even that of Ancalagon the Black, mightiest-known member of that dread race.
All of the immortal or magical races, including dragons, began to weaken as the eras passed on. This was possibly due to the lack of life force that had been given by the Valar during the First Age, and their idea to retreat into the West and cease interfering with Arda in the later ages.
- Glaurung - Slain by Túrin Turambar, also known as the "Father of Dragons".
- Ancalagon the Black - The mightiest Winged Dragon to have ever lived; slain by Eärendil
- Scatha the Worm - Slain by Fram, the hoard Scatha guarded was taken from the Dwarves, thus Fram taking it led to arguments and his eventual death at the hands of the Dwarves.
- The Great Cold Drake - A cold drake of great power which attacked Dwarves of Grey Mountains and killed Dáin I and his second son Frór.
- Smaug - Slain with the Black Arrow by Bard the Bowman, afterward King Bard, of Dale.
- Gostir - a name-only known individual.
When the company Iron Crown Enterprises gained the licensing rights for games made from Tolkien's books, they expanded the selection of named dragons considerably in both Middle-earth Role Playing and The Wizards, a trading card game set in Middle-earth. Also in the real-time strategy game The Lord of the Rings: The Battle for Middle-earth II, based on Peter Jackson's film trilogy, there is a dragon named Drogoth.
In The Lord of the Rings Online: Shadows of Angmar, there are several types of creatures distantly related to dragons. There are giant salamanders, worms (long, quadrupedal serpents) and drakes (smaller, weaker, less intelligent forms of dragons.) There is also an undead dragon in the game, Thorog, resurrected by the forces of the Witch-king of Angmar to aid him in maintaining control over the Misty Mountains. Though not all dragons were mentioned by name in the official texts, names coming from sources other than Tolkien are said not to be "canonical".
In a later expansions of the game, Drogoth the Dragon Lord were featured in The Lord of the Rings: The Battle for Middle-earth II, serving as a commander of goblin forces.
The Lord of the Rings Online: Rise of Isengard, a raid of 12 or 24 players takes place in the lair of Draigoch, another dragon in the Misty Mountains, though much further south in Enedwaith. He, unlike Thorog, is alive, though similarly flies and breathes fire. Another blue-fire breathing individual was portrayed as an ultimate force of Isengard.
- ↑ The History of Middle-earth, Vol. 12: The Peoples of Middle-earth, II: "The Appendix on Languages"
- ↑ The Silmarillion, Quenta Silmarillion, Chapter XIII: "Of the Return of the Noldor"
- ↑ The Hobbit, Chapter XII: "Inside Information"
- ↑ The Silmarillion, Quenta Silmarillion, Chapter XXI: "Of Túrin Turambar"
- ↑ http://middle-earth.xenite.org/2012/09/03/make-room-for-dragons/. retrieved on 16-05-2014
- ↑ The Lord of the Rings, The Fellowship of the Ring, Book One, Chapter I: "A Long-expected Party"
- ↑ The Letters of J. R. R. Tolkien, 144 To Naomi Mitchison
- ↑ The Hobbit, Chapter XIX: "The Last Stage"
- ↑ http://middle-earth.xenite.org/2012/01/09/where-have-all-the-dragons-gone/. retrieved on 16-05-2014
- ↑ http://middle-earth.xenite.org/2013/01/01/are-the-dragons-immortal-creatures/. retrieved on 16-05-2014
- Encyclopedia of Arda article on Middle-earth's dragons
- Concerning the Origin of Dragons article at Cogitemus Accurate
- Dragons at Wikipedia
- Dragons info on Dragons at tumblr