I had a guinea-pig before I got my first cat when the cat was a kitten, and I have to say that they got along pretty well but only when the guinea-pig was in his cage, or in my lap. Whenever I let the quinea-pig out of the cage to run around the apartment, I'd have to lock the cat in the bedroom, because she definitely would "hunt" the guinea-pig- once I forgot to lock her in the bedroom and I noticed it when the cat was stalking the guinea-pig, about to pounce! I didn't want to try and see if she'd actually harm the little critter, or if it was just play. But when the guinea-pig was in his cage, the cat would ingore him completely, so no problems at all. Of course she'd get interested in the critter at times (like when he was making that dreadful noise demanding food
), but she'd only sniff and perhaps touch him with her paws, no harm done. I think it's just normal to display a bit of curiosity, but the novelty wears off in time.