It seems that what Mitsy killed was indeed a gopher. I wasn’t really sure since I haven’t seen one up close before, but now that I’ve had a chance to check out some images online, I can confirm that this one will not be digging any more holes.
Okay, that is a lie, I’ve seen a gopher up close before but it was even bigger. It was a couple years ago and I wasn’t sure at that point if Mitsy or Perl had killed it. Both had been stalking it for weeks. Today’s gopher was about half cat sized. I didn’t think Mitsy still had it in her since she has a hard time jumping onto the couch or my bed. Guess she isn’t ready to kick the bucket without taking a few other living creatures with her.