i've had my cats since they were kittens.They are brother and sister and have always got along. recently (about 3.5months ago) we got 2 puppies. They cats were a bit nervous about this but have sort of got used to it, anyway today i put both cats up on the table where they get fed. As a placed the girl (tessa) on the table blueberry (boy) hissed at her. ABOUT 5 minutes after that i was carrying tessa past blue and she started growling. can anybody tell me what is up and how i can makemy cats friends again?