Any sort of I.D.  on an animal is a good idea, but I had a mixed experience
w/my first ferret Zooey:
 
She always used to wear a collar around the house, w/I.D.  & a bell, and it
did really help to find her (provided she wasn't fast asleep).  but she'd
lose it a lot.  She did escape one night, and apparently lost her collar in
the process at some point b/c the person who found her did not find a collar
on her.  We only got her back b/c we tagged the entire neighborhood
w/flyers.  After that I tried a harness, which only worked for about half an
hour.  I also noticed that the collar (and the harness as well) would wear
off the guard hairs around her neck.  This of course I was willing to live
w/if only she'd keep the darn thing on.  But she's an awfully wiry
creature...
 
Minta
(& Linus, Martin, & Zooey..."Why aren't you amused when I tunnel into the
deepest regions of the couch?")
[Posted in FML issue 2208]