People are creatures of habit. We normally tend to do the same stuff at the same time. Animals are great at picking up patterns. If you're a lion, you notice what's going on when deer congregate at the river, day after day. I don't think animals "tell" time, but are aware of the patterns of daily life. One thing always amazed me was when I had to bring my cats in for their yearly check up. Normally, I wake up, and the cats would be waiting to be fed. On the morning of going to the vet's, there were no cats. They were all hiding. I could never figure out how they knew they were going to the vet's. Mikey used to hide behind the dishwasher where I couldn't get him. I'd have to call and reschedule the appt. What was the tip off? I actually made the appointments from work, so the cats wouldn't hear me. You forget they live with you, and know you very well.