My piggie Ginger can tell time and isn't fooled by weekends, either.
However Daylight Savings Time threw her off for a bit

She probably
thought "silly human...must be some kind of mind game you're trying to
play."
If we're out for dinner and arrive late back, she gets all cute and asks for
food, and when you open the cage and drop it in, she may touch her teeth
against your fingers as if to say "I could take you down if I wanted! Be on
time next time!"
We went away on vacation for 2 weeks once - when she came back to us, she
did laps around her cage to show her displeasure, and tossed out a lot of
her hay by clawing at it.
Guinea Pigs rule the world, we just live in it!
John