My boy cat, Billi started hiding under the sofa in the morning. He does not even come out when I give food out. Aloo, the girl, is out and about, not having a care in the world, but Billi seems to be scared of something. Sometimes he comes out when I look under the sofa, but he stays really low to the ground and is obviously extremely cautious. Then he goes back under the couch. There is no loud noise or dog or anything. I've noticed that he was always under the couch in the morning, but he used to come out to eat breakfast, at least! When I come back from work, he is back to normal. What could be causing this behavior? I am puzzled.