Note she does get thrown off by seasonal time changes in the fall and spring but she only needs about a week to reset.
Maybe I could use my dog instead of NTP and have her press a button that syncs my computers to exactly 20:00? Would work offline at least.
Not sure if he’s relying on other sensory information like certain smells or sounds. I don’t believe that’s the case; we didn’t replace the broken feeder for 3-4 months and he was able to keep time within a few minutes during that period. Our behavior is erratic and changes often; we work jobs with very inconsistent schedules (thus the automatic feeder) so it’s likely not that our behavior is prompting him as well. We can even observe him consistently going to his feeding area on the security camera at the correct time when no one is home. Interesting stuff!
And to further make it weird: our vet told us to feed him multiple small feedings throughout the day so the feeder was programmed for 6 feedings with 2 hour intervals from 9am to 9pm. He hit the mark for all feeding times!
I still think there is potentially some sort of external prompt(s) though. Circadian rhythm is an excellent idea. Maybe that combined with something hard to detect, like lighting levels (which would explain why the timing shifted a few minutes over a few months). Who knows!
At school we used to have a bell mark class ends and without a clock or a watch I could predictably tell when the bell would fire. One time I demonstrated this to a friend (both of us kicked out of class) by counting down from 10 on the second to when the bell rang while looking at a blank wall.
Strange. But nonetheless true.
...or add it to systemd (it will get there eventually anyway)
[1] https://en.wikipedia.org/wiki/Biff_(Unix)#Origin_and_name
My four live in the garden, well protected and I'm too chaotic to keep any sort of regular feeding schedule, but they are fine with that, must be exciting for them if an unexpected feed of carrots or cucumbers drops.
Any time I have an alarm in the middle of the night for any random hh:mm, after just a few days of the same pattern I will naturally wake up exactly 1 or 2 minutes before the alarm as my internal clock knows what to expect. If I ignore it out of laziness and go back to sleep until the alarm rings (literally a minute later) I can break the habit but if I embrace it, it is really accurate and reliable (though thrown off if I went to bed absolutely exhausted, so there are limits as one would naturally expect).
There's a chapter:
“It’s as Simple as One, Two, Three…”
where he talks about and experiments with mental counting and mental time judgement
I decided to investigate. I started by counting seconds—without looking at a clock, of course—up to 60 in a slow, steady rhythm: 1, 2, 3, 4, 5…. When I got to 60, only 48 seconds had gone by, but that didn’t bother me: the problem was not to count for exactly one minute, but to count at a standard rate. The next time I counted to 60, 49 seconds had passed. The next time, 48. Then 47, 48, 49, 48, 48…. So I found I could count at a pretty standard rate.
Now, if I just sat there, without counting, and waited until I thought a minute had gone by, it was very irregular—complete variations. So I found it’s very poor to estimate a minute by sheer guessing. But by counting, I could get very accurate.
he goes on to do all kinds of other experiments like counting while running up and down stairs and more... :)