We’re having trouble introducing our new 2.5lb. chihuahua puppy (5 months) to our 6 year old 15 lb tabby cat. Our other cat, a 4 year, 6lb Sphinx, doesn’t like the newcomer, but has accepted that he’s staying. The big cat has already taken a chunk of skin out of the dog. And he continues to stalk him whenever we’re not guarding the puppy. How can we aid the big cat’s acceptance of the li’l intruder?