Every night at 10:00 PM, like clockwork, my frogs crawl into their nighttime hiding spots. They choose the same spot every night and head to that spot at exactly the same time. I'd be less surprised if they didn't "go to bed" before any of their lights start to dim. The lights go out starting at 10:30 and end going out by 11:00 PM. I'm wondering if anyone else has noticed this or has a good explanation for me. There is probably some hormonally regulated system like in people, but I know next to nothing about frog physiology. Anyone have any insight for me?