[Dalin]

As far as I can tell, all the other "Mundane" creatures in Monsters are basically humanoid in shape. Based on the wording of physiology in Adventurers, I could see a dragon counting as a humanoid. I would probably rule, however, that it is an animal for the purposes of physiology. As you mentioned above, if you need a specific skill to strike the vitals on a wolf, tiger, or bear, it makes sense that a dragon would fit into the same general category.