switching male BP from FT mice to FT small rats

Are there any tricks when it comes to switching a BP over to a small mouse? I tried rubbing the rat on the mouse to scent it to no avail. He is big enough for a small rat, but does not want to hit it and shys away as if it is scary.

Did you heat the rat up enough? Try zapping it with a hair dryer right before offering it. I always get a killer feeding response when I do this with any kind of prey item.