Many of these carriers will work beautifully to carry your cat, rat, ferret, or iguana just as easily as they will carry a small dog. Just look at the weight capacity and keep in mind the weight capacity is only an approximation. If the carrier will hold up to 12 pounds, will it fall apart and ‘break’ at 12ponds 1oz? No. If your pet is dimensionally correct for the carrier you are wanting, but a little chunky so it’s about a pouund over the weight capacity, you should be fine.