My yorkie girl gets jealous but not for my sake. On the occassion I let the cat on my lap, she'd be hopping up and down or staring intently at us when normally, I'd have to beg for her attention even. Just yesterday, I picked up the cat in my arms in preparation of giving her a long overdue nail trim, I got barked at!
I'm like, "Excuse me???" and she belted out another one! Of course, that's when she got sent to time-out on her pillow but couldn't help herself from peeking around the corner to look at what mommy and her favourite chew toy is doing. I'm not so naive to think that she is being possessive of mommy, hence, the vocals, she was actually telling mommy that the cat is HERS. LOL. Anyway, cute as that is, I discourage that kind of behavior.
My girl gets jealous if the cat's giving mommy attention and not her.
One of the first words she's learned since coming home with me is our cat's name. She used to fly out of mid slumber to look for the cat once you speak the cat's name.