The pooch often sleeps next to the trash can by my wife’s bed. When I used to come into the room and sit down about 12’ away, she would eventually awaken, look my direction and either come out into the middle of the room for me to take her out, or move five feet to a corner behind my wife’s easy chair where I couldn’t see her, so I wouldn’t bother her by taking her out. I suppose she understood the human idea “out of sight--out of mind.” I assumed it was her subconscious that smelled my scent and alerted her to my presence.
Now that she’s basically blind, she still awakes after I’m in the room a few minutes, but she now raises her head and sniffs the air repeatedly while making no effort to look at me. Eventually, though, she DOES look my way (blind though she is) and makes the same choice as before--go out or hide. I’m now sure it’s her nose that wakes her from her sleep. That ability is part of what makes a dog a good guard.