Extra Info | thebookofdragons

Toothless in the book is a green, small Garden Dragon
The NightFury in the movies was at first going to be more wolf like in apperance but a black panther desktop screen changed their minds and made him more cat like
The sounds of Toothless are a combination of elephant seals, horses, elephants, tigers and domestic cats
In the movie when Hiccup is staring at the shot down Toothless, you see Toothless's wing pass over his closed eye and then you see his eye open, this was actually an accident in the animation process but they kept it because it was so creepy

In the book, Fishlegs is smaller and scrawnier than Hiccup and he was never accepted by the vikings but he was actually Hiccup's best friend and sidekick
In the book, the vikings wanted to TRAIN dragon not FIGHT them in order to be accepted.
In the books Astrid did not exist and Hiccup did not love her, (hence that she was never there) but Hiccup was in love with a strong sword fighter named Camicazi
Hiccup was the only one in the movie to be seen killing a dragon (Red Death)