User blog comment:Httyd big fan/Thirty-Fifth Dragon Fight Club Match: Night Fury vs. Light Fury/@comment-37045953-20190610220259/@comment-38814262-20190723013000

With that “aggression” thing, keep in mind that those are different circumstances. At that point, Toothless was used to the fact that there WERE good humans in the world. Also, a side effect of befriending and being basically tamed by Hiccup would most likely be that he would become more docile. Meanwhile, Toothless’ Light Fury has been hiding from humans for probably her whole life. She had learned they were a threat, the kind of kill-on-sight aggression that Vikings held toward dragons before. I think that the two species have the same base level of aggression, but, just like any species, it can fluctuate over time and between individuals.