interesting, havent heard that one before. So take my bp out of his enclosure (29g tank) and put him in a smaller enclosure (his pervious 19g tank) and throw in a rat and see if he takes it? What i dont get if when u say take the rat out and try again, do u mean take the rat out and wait a half hour or so and try again, or take the rat out and try again in a few days?