We recently acquired a hamster. Thalia was, for a short time, enamored with it. She still sleeps next to the cage and will spend time watching the hamster, but hasn't been overly predatory.
Then this morning, the hamster nearly ended up in Thalia's fat kitteh belleh. I'm home sick but wanted to get up for a few minutes after taking ibuprofen. I noticed the cat keeping an eye on something in the corner by the closet and dresser. I assumed it was an insect of some kind. I turned the light on, and there was the stupid little hamster. Insert profanity here. I hauled the cat upstairs to shut in the office and got David to help catch the little bugger. On my way up I glanced at the cage and noted that the cage door was open.
Between the two of us (but mostly David) we got the thing cornered and caught, but not without having to move some furniture. The cage door is wired shut now. We're really not sure if it was the kids, the hamster, or the cat who did it. Perhaps a combination of all three, but the kids were asleep and the hamster couldn't have been out for more than a few minutes. The cat or the hamster might have gotten lucky and opened it by accident, but I'm pretty sure the two of them put together aren't smart enough to open the cage intentionally.
Interestingly, Thalia wasn't hunting the hamster like she hunts mice. She was keeping a careful watch on it, but wasn't really aggressive or overly playful. Perhaps being exposed to the hamster in the cage for a few weeks has dimmed her instinct to eat it a little, or at least confused her. The hamster also didn't seem at all fearful of the cat. It was all "Yo, what up, kitteh?" and Thalia was all "Yuz fud or no fud? In mah belleh?"
I really glad I got up when I did.