Snakes are reptiles mentioned very briefly in the How to Train Your Dragon Book series.
Snakes are legless reptiles of the Suborder Serpentes. Some lizard species are also legless, but have arrived there through a different evolutionary path separate from snakes. Almost all species skeletally only consist of a spine, ribs, skull, and a hyoid bone. Many snake species have venom for hunting and defense. Venom is modified saliva and contains a complex mix of proteins. The venom is kept in sacs at the back of the snake's head. They are connected to hollow teeth - the fangs - that can inject the venom when prey is bitten. The fangs themselves are usually folded carefully into the mouth when not in use.
Snakes inhabit a wide variety of climates from deserts to the ocean. Sea snakes (Subfamily Hydrophiinae) live entirely in their marine environment, except for a few species. They cannot move well on land. Offspring are live-birthed in all sea snake species except for Genus Laticauda. Generally sea snake bodies are narrower for more streamlined movement through water, and their tails are paddle-like.
One European snake species mentioned in the Books is the European Asp (Vipera aspis). It lives in Southwestern Europe, so historic Vikings would have had little encounters with this species. Nonetheless, it is known for its very poisonous bite which causes severe pain and localized necrosis, as well as possible kidney disfunction and death. The asp has the classic triangular head seen in poisonous snakes, and a brown body with black patterns on it.
Snakes have no function in the Book series except for descriptive purposes.
In actuality, snakes are eaten and kept as pets.
As the Hairy Hooligan Tribe and the Meathead Tribe convene to discuss what to do about the Green Death, a Seadragonus Giganticus Maximus that washed ashore on Berk, the crowd shushes Gobber as he is about to read from the book, How to Train Your Dragon.
|“||Ssssssh," hissed the crowd like sea snakes as Gobber cleared his throat.||”|
|— Book 1|
Snakes are mentioned as being related to a tentacled dragon called the Monstrous Strangulator.
|“||A Strangulator was a gigantic Monster genetically related to dragons, octopuses, and snakes.||”|
|— Book 2|
|“||That creature was a disgrace to us green-blooded FireBrothers of the Snake.||”|
|— Book 3|
The connection is made again by Hiccup to a Sad Gronckle:
|“|| I am the Venomous Vorpent,|
Deadlier than an asp soaked in arsenic,
More toxic than toadstool-soaked tarantula.
Are your cough-y and cold-y and snotty and sneezy?
Are you mad? Are you sad? Do you feel queasy?
Is your skin so hot it is starting to smoke?
Is your throat so stiff it is making you choke?
If you fall down DEAD, perhaps you too
Have been stung by the VENOMOUS VORPENT.
|— Book 4|
The long, sinuous tongue of the Doomfang dragon is compared to a "gigantic muscly snake".