Creep (my other cat) is taking it surprisingly well. In his younger days he was quite the little hellion. Any time the subject of another cat, or even a dog got brought up, we had to consider that Creep would torment any new additions. Just a few weeks ago we turned away a kitten that our neighbor offered us. However, that kitten had a home, so there was no guilt or consequences involved in turning it away.
Max, on the other hand, has obviously been stray for a while. He's got no meat on him. He's all fuzz and bones. He was dirty and smelly. We had to take him, regardless of how Creep might react.
He's been good, though. He's hissed at Max a couple times, but all in all he seems to be taking it in stride. I chalk it up to him being older and less full of piss and vinegar than he used to be.
