Why do creatures give up?

[cailic]

Something that has kind of annoyed me from the beginning is how creatures will only chase you for about 300 yards than stop.  Typically, I  think creatures have more stamina than a person so I have never understood this. 

 

How do you change this give up and quit distance?  I have the mod, I think it's called, "Run after me and swim after me".   But that doesn't seem to do much.  Or is there perhaps another mod already out there that gets rid of the tethering issue?

 

Creatures don't present much of a challenge if you can just run past them.