Behavioral cycles that repeat daily are called circadian rhythms.
Circadian rhythms are behavioral, physical and mental changes that occur in living organisms (plants, animals, fungi and cyanobacteria) and follow a 24hours (daily) cycle. Circadian rhythms regulate many physiological processes and they are influenced by external cues such as sunlight and temperature. They determine when to sleep, when to eat or whether an individual feels wide-awake, or feels tired at different times of the day.
