We have an elderly gentleman cat named Bob who frequently "calls" after he's eaten or gotten up from a nap. He'll wander around from room to room yowling. He's the only cat we've ever had that does this. It's an eerie sound when you hear him in the middle of the night. Often, if I call his name, he'll stop but he won't come to me. He just shuts up! I wondered if anyone would know what this calling behavior is about. Is he looking to find the other cats (we have 3 others), is he looking for reassurance, or is it an alpha behavior?