In the book How to Train Your Dragon, Hiccup doesn’t have a love interest. Furthermore, Toothless is about the size of the Terrible Terror breed, and he is also green and red, not black. Toothless also got his name because when Hiccup first found him he had no teeth. He grew one tooth, only to lose it shortly later. The producers decided, with the approval of author Cressida Cowell, that it would be more cinematic to make Toothless large enough to be ridden as a flying mount. As such, Toothless was completely redesigned as a rare Night Fury, a highly intelligent breed of dragon evolved for speed and stealth. His personal name in the film derives from Hiccup’s observation about how his teeth are normally retracted into his jaws so they don’t interfere with his fire breathing, which is typically projected as an explosive pulse.