I've gotten them to eat small frogs like Wood Frogs and also small snakes. If nothing works and you are determined to keep the racer you may have to force mouse tails for a while. In time the snake will accept mouse tails without being forced and may take pink mice soon after. Also try scenting defrosted pink mice with chicken blood from store-bought chicken or rubbing the defrosted pink on uncooked chicken. Mmmmmm...who could resist?