[quote=@Halvtand]
The only one I could go against is really number two, could you elaborate on this? Also, would you say that monsters cannot be reasoned with?
[/quote]

Sure. The creature is a malignant force even where it lives. Maybe it's knocking down every tree in its path, or eating so much that the other creatures living in the area can't get enough food for themselves, or its got some sort of potent venom that leaves areas it moves through barren or is seeping into the water supply and making everything sick. The point is its very existence is not healthy for the environment it finds itself in.

Now, you might be wondering what differentiates that from an regular invasive species and there's really nothing. Most of the signs can be found, on an individual basis, even in cases of real world animals. That manticore haunting the woods might be perfectly adapted to its native environment and was just driven over the mountain by something or carted in with a traveling circus. In that case its still an animal. A hungry, confused, and desperate animal that should probably be put down for the good of the area, but still just an animal. That's why these are all just signs. To my mind, yes, the difference is behavioral and with monsters the behavior you're trying to identify is maliciousness. Animal act violently out many things; fear, pain, hunger, a desire to mate, a desire to protect their territory or offspring.

A monster acts violently primarily out of malice and since you can't talk to an animal and ask what it's feeling and why it's doing the things it is all you can do is look for that malice in its behavior and make your own best judgement about what it is you're dealing with. That's also why they can't be reasoned with any more than you could ask a staving tiger to please not eat you. There's no higher thought to their actions. A hungry tiger will eat you because that is the nature of a hungry tiger. A monster will kill you just to see you dead because that is the nature of a monster.