Circannual Rhythm

A circannual rhythm is an internal biological cycle that repeats roughly once every year. It influences behaviors and physiological processes such as migration, hibernation, reproduction, and mood changes, aligning them with seasonal environmental changes. These rhythms are regulated by internal biological clocks and are influenced by external cues like daylight length and temperature. Even without environmental signals, many organisms maintain these annual patterns, helping them adapt to seasonal variations for survival and reproductive success.