I can't remember. I thought it was cool to see the difference between feeding rats and mice in boas. One of them has only had mice and the others have been on rats since birth. I just recently switched the little guy over to rats and he's almost doubled in solid girth. It was just a little experiment I did to see the difference. He was never starved or anything, but just fed appropriately sized mice instead of the same in rats. He never grew very much, but was always healthy looking. He now has the feeding response of a retic!