We have a bp (Slither) that isn't interested in eating. She seems to be fine, still strong, has color, she's very active and she just shed again. When offered a mouse, she looks at it and passes it by. We thought it could've been the mouse, so we put a different one in...still no interest. Slither is about 10 yrs. old. How long can they survive without eating? And any answers are appreciated.