My pets had an expectation of events to happen at specific times. Dog would sit by the door and 'expect' to see $family_member arrive home from school/work. (noteworthy for those that had regular schedule and always got home about the same time.)
My last cat expected to be fed at the same time every day. For the first couple of years I had my cat, my job & routine were identical every day. Wake at 6am, feed cat, goto work.
On weekends this bothered the cat so he would wake me up at 6:01 so he could get his food. I hated that he would never let me sleep in. Fast-forward a few months to the daylight-savings change; and then at 5:01 he started expecting food. The damn cat had an internal clock that was very accurate.
So I am sure a lot of animals have internal clocks and don't solely rely on "% of sunlight" to determine behaviour.