belly pop open? on the mouse? I have never seen that, or had that happen. hmmmm I just fed my bp-George. I use a seperate container... I put the mouse in there, under the heat, for a few min, then add my bp. Leave them together in the container under the heat. within secs, George has already constricted the mouse, & is ready to eat... I actually got a picture of him eating today. It was pretty neat, I took a pic & then left him alone. He is sooo content & happy now.!!!