I don't believe that Siamese are normally big cats, it's just that Ming is on meds and they have put some weight on him. He is a very tall, long, solidly built, cat, and before he went on meds, he weighed about 13 lbs. I have to leave food out, dry, for my cats all day as my vet has order Mac to put on weight! Mac used to be about 9 lbs., but now he tips the scales at about 6 or 7 lbs. D*med if I do, d*mned if I don't.