Al has regrown his tail! It started a couple months ago; at first we didn't recognize what was happening, but now it's undeniable: a fluffy, foxy new tail!
Some salamanders can regenerate lost limbs, but I know of no vertebrate animal that can regrow a lost tail. We showed him to a zoologist at U.W., and she's amazed, might even submit a paper about it. Our dog is a biological curiosity!
I hope it stops growing, or he's gonna look real funny.