I don't have too much advice to offer seeing as how I'm still very new to being a rat mommy. I do know that you will want to get two rats because rats are VERY social and they get lonely if they aren't in pairs. There are a lot of people that have cats and rats, but it's normally best to introduce them when the cats are kittens. So far luckies4me, YellowLabLover and this website Rats Rule have been my best resources.