Dragons are Berk's (perhaps even Earth's) second dominant species, a race of powerful reptiles with two distinguishing characteristics: flight and fire generation (although not all dragons have both/either).
In the movies
- See Also: Dragon Anatomy
Most species have a fear of eels, a limited number of 'shots', and a blind spot. Most dragons also have protruding teeth from their lower mandible. Within the species, there are many different breeds, ranging in size, shape, color, and abilities, from the lizard-sized Fireworm to the gargantuan Bewilderbeast.
Dragons are loyal to their owners and most will protect them when they are in danger. They will do anything to earn their trust and will not leave them.
Some dragon species can have different colored scales amongst individual specimens (such as the Stormcutter, Deadly Nadder, Gronckle, Monstrous Nightmare, Hideous Zippleback, Rumblehorn, Hotburple, Typhoomerang, Snaptrapper, and the Thunderdrum etc.) while some retain the same color throughout their breed (such as the Night Fury, Scauldron, Skrill, and the Timberjack etc.)
They are most likely warm blooded, strong evidence of that is obviously the fact they live up in the cold north and also with some species (such as the Gronckle, Scauldron, and the Hotburple) being able to take in things from their environment like geological minerals and water and produce enough internal heat to melt and/or boil the materials while others (such as the Bewilderbeast, Shivertooth, Groncicle, Woolly Howl and the Snow Wraith) are able to cool water down or produce ice. They have different types of firepowers, ranging from fire to ice, sonic sounds to acid. The Book of Dragons shows that there are rumored five stages in a dragon's growth: Egg, Tiny Tooth, Short Wing, Broad Wing, and the incredibly rare Titan Wing.
While the natural diet of most dragons is fish, they will happily eat other things, such as vegetables, and man-made food like bread. Most dragons, however, eat fish like Mackerel and Atlantic Cod and sometimes, other forms of meat. The Monstrous Nightmare and the Changewing have been shown hunting wild boars, so it may be that at least some of the other larger, land-based species do also. The Typhoomerang enjoys eating eels,The Skrill likes sheep and the Deadly Nadder likes chicken. Some dragons like the Red Death and Deathsong eat other dragons. Some dragons even eat invertebrates and small animals as shown by a Raincutter eating grubs and the Razorwhip enjoying Sea Slugs. During the war with the dragons, it is fairly clear that they were also willing to prey on humans, as a Monstrous Nightmare swallowed Gobber's arm and enjoyed it. The trained dragons on Berk will not hunt farm animals, but they will accept their cooked meat if given to them by humans. Dragons also enjoy vegetables and plants.The Flightmare eats algae suspended in water, which other dragons can also eat. The Scauldron enjoy the Blue Oleander Flowers that give its species venom.Dragon Root and Dragon Nip, are plants that dragons eat. The Dragon Root is loved by dragons and can make them wild and fight over it. Only the Gronckle is immune to it. The Dragon Nip, on the other hand, soothes the wild dragons. The Monstrous Nightmare has been shown eating corn.Some can also eat other substances, such as the Gronckle eating rocks for food and to convert to the lava they fire. The Gronckle can produce a variety of lava or metals after eating different rocks. Such as lava rocks, Gronckle Iron, magnets, different coloured lava and a transparent material. Snafflefangs enjoy eating geodes.Toothless has been seen snatching bread from Hiccup, though he did not eat it, the very fact that he wanted it shows that dragons could have eaten bread.
Dragons have three major predators: healthy adults can be in danger from rival dragons and humans, and wild boars prey on young and injured dragons.
Dragons are social animals, living in large colonies with their own kind and other dragon species. A large alpha dragon like Red Death and Bewilderbeast normally controls the nest. They gather together to mate and lay eggs. These behaviors have also moved on to other species such as humans, as well as domesticated animals like sheep, cattle and chickens, thanks to the training and semi "domesticating" of dragons. It is unknown whether they mate for life or not.
In the books
Dragons in the books are described as being very sneaky selfish creatures who are never thankful of anything and will only obey to brute force and yelling. Most dragons pride themselves on this fact and will easily abandon their masters as soon as danger is on sight. Most dragons have a proud nature, often referring to themselves as aristocrats and green-blooded. Like cats, dragons have a cruel streak, and they like to play with their food before they kill it. They also love to play on fire since their skin is fairly fireproof, in some species even completely immune to it.
In Berk many of them live as babies in the dragon nursery, a cave where they hibernate together. While hibernating a dragon enters into a very deep coma. Some dragons, however, don't hibernate and they are called 'evergreen' dragons. Dragons have three eyelids which they can open at will when sleeping. Only when all three are open the dragon is fully awake. Dragons communicate with each other in a language known as Dragonese. This language is specially hard for humans to speak since humans don't have forked tongues. Dragonese is punctuated by shrill shrieks and popping noises, and sounds. The word "pishyou", when spoken by a human, for example, is pronounced very much like a sneeze.
A dragon's diet consists mostly of meat, but they are supposed to eat plenty of vegetables and, weirdly, lots of wood, like small branches, twigs and the bark of trees. This helps them with their firebreathing. A dragon that can't breath fire gets very sick and eventually explodes.
Most dragons are four legged with a pair of wings and firebreathers. The fire from a dragon comes from two particularly small, almost undetectable holes in a dragon's throat. From these holes, it releases a breath heavy in oxygen and extremely flammable. This gives the dragon the ability to not only breath fire but to do it underwater (since the oxidizer component is present in the breath itself). A dragon may choose not to ignite its breath, and due to its oxygen rich nature, it can be inhaled by a human. Dragons are also capable of living underwater as they have gills behind their horns that allow them to suck the oxygen in the water. Most dragons live on land though. Their size and coloration varies depending on the species. The smallest dragons are the bug sized nanodragons with the biggest being the Seadragonus Giganticus Maximus. A dragon's gaze is said to be hypnotic, a staring contest with Toothless once made Hiccup very dizzy and he was just a baby. Their eyes also shine in the dark.
Dragon's intelligence greatly varies in the books and it seems to depend on the species. Some dragons like the Monstrous Strangulator are shown to be stupid enough to be easily tricked into killing themselves, while others like the Seadragonus Giganticus Maximus are proud, intelligent creatures who love riddles and have been known to speak philosophically about abstract concepts like death.
- The dragons in the books differed from the ones in the movies and series on most occasions.
- In the game, Dragons: Rise of Berk, the dragons can be trained further by Valka to allow them to change to the final stage of a dragon's growth, the Titan Wing.
- It can be observed that, apart from growing in size, the color of the dragon's scales greatly changes, with only a few parts of its body unchanged.