Light is the primary zeitgeber for most mammals' activity cycles.

Question

Quizplus · Accepted Answer

Light is the most important environmental cue for regulating the circadian rhythms of most mammals, including humans. The suprachiasmatic nucleus (SCN) in the hypothalamus of the brain receives input from the eyes via the optic nerve and uses this information to entrain the body's activity rhythms to the timing of the external light-dark cycle. Other factors, such as temperature and social cues, can also influence circadian rhythms, but light is the primary zeitgeber for most mammals.

Light Is the Primary Zeitgeber for Most Mammals' Activity Cycles