Cats supposedly fail the mirror test, but I think they're just disinterested. There are a lot of videos of cats being shown live video of themselves and their owners, with the owner's face modified to look like a cat. In many of these the startled cat immediately turns around to look at their owner, seemingly indicating an awareness that the video they were being shown contained themselves and that the weird cat-like human creature seen in the video was behind them.
Very late comment, but I find this truly amazing. Yes, some cats are too dumb to fully grasp what's happening, but they do give the human a look of concern. Their reactions could be manipulated, but I find interesting how dogs look forth and back, while most cats remain fixated in the real human. Not very rigorous, but very cool anyway.
I've always thought a good mirror test shouldn't be just a mark, but something that looks like a venomous insect, to stimulate the subject to look for it.
Compilation of such reactions that was posted on HN a fee days ago: https://youtube.com/watch?v=Jto2peSOLac