Typically most animals work on a flight or fight response. If they think they can win, or feel cornered they will likely fight. However if they feel overpowered they may flee.
In the case of wild dogs, wolves and the like, gunshots might be enough to scare them off. An example would be if a pack of wolves circled you, and you fired your .44 revolver into the air. The sound alone might be enough to scare them off.
However for something like a rad scorpion, deathclaw or other such large dangerous animal, they have much less to fear and know that they are at the top if not close to the top of the food chain.
Lilfyffedawg, I think you morale, right? Which would be "The state of the spirits of a person or group as exhibited by confidence, cheerfulness, discipline, and willingness to perform assigned tasks." according to the dictionary.
I think if you had a pack leader with a bunch of wolves he might dictate what the group did.
Specifically you would see caravans, slaver groups, mutant patrols, etc that IF they had a commander or boss around would probably end up being more coordinated and efficient in combat. However if you started cutting them down fast, no amount of leadership will keep most humans from fleeing.
Mutants are another story as they may be too stupid, proud or bloodthirsty to flee. Though you might see a few it would be rare.
An example of fleeing and morale would be in the Den in FO2.
You've got metzger and you're going to kill him (I always do.) but he has a lot of guys with him.
You come in guns blazing and Metzger would probably get everyone organized and behind cover fast enough to keep you back.
However, say you waltz in to his 'office' stand next to him, then unload two barrels from your shotgun into him... he flies backwards then Sulik lets loose a burst from an smg, killing another guy.
Metzger is dead and the group just lost another comrade, morale would take a big hit. Then considering there is almost no cover in his office save for a chair and a refridgerator, these guys might not see themselves having much of a chance.
The response? They all scatter, maybe a few taking pot shots but they try to find some protection.
Maybe then Metzger's right hand guy steps up to lead. You know, that guy you talk to when you come into his building. Yeah, so they suddenly are willing to fight again.
Now, the games already have a flee mechanism in them. If you hurt a guy enough, or cripple a limb plus inflict damage, most of the time they will run from you. But you usually have to hurt them seriously beforehand.