Anecdotal and very "noisey". My cat badgers me when I'm up too late (midnight) even though it's been hours since the sun set. She badgers me if I sleep in too

Anecdotal and very "noisey". My cat badgers me when I'm up too late (midnight) even though it's been hours since the sun set. She badgers me if I sleep in too long on the weekends, etc. She seems to have an idea of the day-to-day schedule and get's upset if it's not followed. So at least cats seem to display evidence of knowing a "schedule" based on more cues then just daylight/hunger