 What about cats that are house cats that cannot disappear? Do people notice differences in their behavior? Oh, sure. They'll do things. They'll not eat their favorite food. They will follow you around the house as if they don't want you out of their sight. Or they will demand to get outside and you'll open the door and they won't go out. They'll expect you to go out with them. One case, a cat got on the favorite armchair of the owner and the cat had been forbidden to get on that chair. It got up on top.