My boy Joe aka "Josie" was the same way when we brought him home to live with us. Now everyone (4 cats, 1 bird and Joe) gets along except my oldest cat "Stanley". We seperate them when were gone too but only to protect Joe. Stanley (the cat) would beat his a$$ if given the chance and Joe is a bit intimindated. It's a funny site to see a 85lb male dog running and hiding from a 6lb cat!