The movie is loosely based on the 2003 book of the same title written by British author Cressida Cowell and published by Hodder Children's Books. Cowell cites the Inner Hebrides of Scotland as an inspiration for the book. the film was followed by How to Train Your Dragon 2 (2014) (2014).
Toothless is male, evident in a scene where Hiccup says to Astrid, "You just scared her," and she replies, "I scared him! And who is her?"
