Private Back to Sender
Well... it is a little strange, I'll admit. Just be technical about it
The wolf craves human flesh, so through the magic that is used to turn into an animal (called becoming an Animagi in my world), everything is transfigured leaving all traces of human behind. The wolf bites and scratches itself out of frustration but also out of the fact that my own blood is still partially human, whereas the pure magic of turning into an animal changes everything and makes them just another animal. Because wolves (and werewolves as well) are naturally drawn to being in a pack, the wolf ended up adopting my friends as his own pack, which helped them to distract the wolf from being self destructive which in turn helped me.
I hope that made sense and didn't totally freak you out. Can I ask why you were curious?