"Sharkworms are a kind of dragon that look a lot like sharks."
―Hiccup in Book 3

The Sharkworm is mentioned extensively in How to Speak Dragonese, and very briefly in How to Train Your Viking.

Physical Appearance


Sharkworms have multiple nicknames including Pirate Dragons because they have legs and can crawl onto a ship like a pirate and wreak havoc. They are also called Thor's lapdogs because their hammer-shaped heads. Adults can reach six meters long. They also have wings, along with crevices along their body into which to tuck the wings to reduce drag while swimming. Sharkworms have a dorsal fin that, while swimming, sticks out of the water like a shark's dorsal sin does. However, the dorsal fin of a Sharkworm is distinguishable by its serrated edges, which sharks lack - "a black fin, with serrated edges like a bread knife."

Their head is similar to that of a hammerhead shark in that their eyes are set away from the body on "stalks". One passage in How to Speak Dragonese also indicates they are two-headed, though there are no depictions as such.

"These two-headed beasts had eyes out on stalks, rather like a hammerhead shark."
How to Speak Dragonese

Sharkworms also have retractable jaws which sound like what most shark species have.

"Their back set of teeth could shot forward to grab prey, then retreat back."
How to Speak Dragonese

Sharkworms have a minimum of 5 rows of teeth in their mouths.

"They drew back their first sets of teeth in vicious snarls, and the second sets shunted forwards as if they had a life of their own, madly snapping together like an automatic killing mechanism."
―Book 3


Sharworms have short muscular legs and can move very quickly onto a ship or on land, even outrunning a human.

According to How to Speak Dragonese, Sharkworms are also able to breathe fire underwater.

"One of them let out a jet of fire like an underwater torpedo, and the barrel burst into flames."
―Book 3


Sharkworms are almost exclusively water creatures, and can only survive in full air for about 10 minutes.


Sharkworms are a vicious dragon inhabiting warmer parts of the sea, notably in the Summer Current which runs in the Barbaric Archipelago.

Also mimicking sharks, Sharkworms go into a frenzy at the smell of blood, whether on sea or land. They have excellent smell and hearing, too. Because they are sensitive to detecting blood, they often only attack if you are wounded.

Sharkworms sided with the dragons during the Dragon Rebellion.


In How to Speak Dragonese, Hiccup plainly states that "Sharkworms are untrainable."


How to Speak Dragonese

Sharkworms are seen as a part of the show for the Romans at Fort Sinister. Hiccup and his friends must battle them in front of the audience. However, they utilize the Sharkworms in their escape.

How to Train Your Viking

Sharkworms are mentioned in this novella accompanying the main Book series.

The Incomplete Book of Dragons

Sharkworms are mentioned in this reference book in the 'Dragon Key' at the back of the book.



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