Do animals sense the passage of time?

I believe they do. All of the cats I've had know when it's feeding time. And it remains the same even when daylight saving time goes into effect. They don't know it's a hour different, so they show up at the normal time. I've even had cats that knew what time I should be home and would go to the door and wait for me according to roommates I've had. So, yes, I'm convinced they have their own internal clocks.

I do believe so. Our Rottwieler was never late for the bus when the kids got home. Even if I was busy and lost track of the time, she would bring her leash at just the right time and off we would go. My African Parrot knows the days of the week. There is something that I do every Thursday and if I stay home she gets all upset. It really messes up her routine. She even knows that the last Wed. of the Month is a day that I will be gone, because when I do not go the same thing happens. If the meeting is cancelled, I try to find something else to do just so she can have her routine.