Reading your post (OP), I think you're confusing hunting with self defense.
If an animal poses no immediate threat to you (mt lion or bear passing by, no matter whether that's at 100 yard or 3 feet), but you kill it, then you were hunting. In that case here in the US, you better have the proper hunting licenses and/or tags, and the season better be open. If not, then you'd be committing an illegal act and would be considereed a criminal by law.
In that case, you would be the aggressor (hunter), and shot the animal without it posing an immediate threat to you.
Sorta like if you shot another hiker because you thought he MIGHT attack you. That'd be murder. But if the other hiker had a weapon, and was threatening or trying to kill you, then that would be considered self defense in most states.
An animal is no different. In general, if a "reasonable person" would think that the animal was attacking you, then you'd be justified in shooting it in self defense.
If the animal is attacking you, then the animal is the aggressor instead of you.
Bears are known to "false charge" at times. It's a bluff meant to scare you away. You've no way of knowing it's intention when it charges though, and some have killed people. So, if it's charging at you, and is close enough to pose a threat to your life and/or well being, then shoot it if you can. If it's not threatening you, then let it pass and be on your way.
A mt lion that's passing by you doesn't necessarily pose a threat. One that's stalking you very well might. There's the difference.
And no, I've never really thought about such things when it comes to animals. To me, the answer seems rather obvious. Not that all situations will be cut and dried one way or the other, but in general if you don't feel threatened, then don't shoot unless you're actually hunting that animal.
Last edited by Daryl; September 18, 2009 at 06:34 PM.