My dog knows when bedtime is. It’s when the sun goes down. Food time is before bedtime. If I come back after dark, yep, I get some stern looks from my dog. Don’t know if they can tell that days get shorter or longer, certainly isn’t based on the hour of the day if I miss bedtime...
I can be gone 15 minutes and my GSD will act as if I’ve been gone for 2 tours in Iraq when I get back. Then when the greetings over and she’s done throwing a ticker tape parade for me, the dog, in a barky talk back scolding tone and will let me know it’s not happy about me leaving.