Today, I found out.
I was getting Tol Barad dailies done, working toward the spirit trinket. It was the much-hated quest to kill 12 spiders. Killing quests don't bother some people, but I get cranky at having to kill a decent number of mobs, since I tend to pick them off one at a time so I'm prepared in case someone jumps me. I hadn't gotten more than three spiders in when I found myself off to the side with no target spiders around and a lone fox. I took one look at that fox and knew it was going to drop the minipet fox. Mind you, Kalliope had never had luck farming for that thing, so I had given up looking.
So I kill the fox, and sure enough....