I've had hamsters and cats at the same time but not piggies. My cats got along with the hamsters as long as I didn't leave them loose in the room together. I do have a couple of pictures of my then cat, Tippy, sitting by Calhoon's (my hamster) cage watching him. She could never get her paw through the bars to get him. Calhoon never seemed too stressed out by her watching him. I too, can't wait for the new adventures of Edwina and the Piggie!