>So, any idea's how to block a 1/2 in gap below the door?  (short of
>cutting the door in half and caulking the gap, which they would pull up
>and eat anyway)  Since I know some one will try this again.  BTW, it is
>really only 1/2 inch, I went back and measured it because I couldn't
>believe anything could get into that small of a space."
 
I have used a scrap piece of linolium flooring folded how ever many times
needed for the thickness.  They can dig to thier hearts content and not
dammage anything.
[Posted in FML issue 4212]