Animals get both more credit and less - it depends.
Animals may get closer before I shoot - they are given a little more credit in that sometimes they only want to look mean but aren't really going to attack. Like the post about the dog growling across the street.
Animals get less credit in that I don't feel the need to be in imminent danger of my life before I drop them. They are dogs - legally just property - so killing them has a much lower bar than killing a human. If I think I will be bitten at all, I feel it's ok to shoot earlier than I would a human.
So my lame answer - "it depends".
I don't feel compelled to try to discern the intent of either animal or human attacker. I can't tell what is going on in their mind. I can however look at their actions and base my response on that.