What makes arctic animals’ biological clocks tick?
How do animals living in 24 hours of light during the Arctic summer know when to sleep and when to be active? Answering this question may improve our understanding of biological clocks—the internal, genetically programmed cycle of rest and activity that affects the behavior, metabolism and physiology of all animals, including humans. A better understanding may also help solve problems, such as shift-work fatigue, jet lag and even seasonal affective disorder, often associated with disruption of the biological clock. G. Edgar Folk, PhD, emeritus professor of molecular physiology and biophysics at the UI Carver College of Medicine, has spent a lifetime pursuing these questions and finding answers that have helped build the field of biological clock research. Folk notes that humans have a natural circadian rhythm of close to, but not exactly, 24 hours. All biological clocks are adjustable and respond to environmental cues such as sunrise or sunset, which continuously reset the clock and ke
