If you've read the book, you know that its plot is pretty much completely different, with the same main ideas in it... The green death, hiccup, and dragons.
But in the book, toothless really is toothless, and is a common, small for his breed, garden dragon. And the dragons share no bond with their trainers, either... The book was a good enough read (I sat down today for 2-3 hours to read it) but it didn't have much to it, and I much prefer the movie, plot and all.