mister knows when r. has come and he runs down the stairs like a pup, forgetting all about his arthuritus and burrows his head in her lap. i laugh. he looks over at me and says with squinty eyes, thank-you for bringing my angel! when she's not there he stands at the landing until i say, you want me to carry? and wags and smiles. i think he smells her scent on me, or he senses that i am different when she's there, or he just knows, and is very happy.