Day man! Fighter of the night man! As someone who has never been able to wake up in the morning, I've always been curious how much of that was determined and how much I might have control over it. What does the science say? Dr. Lindsey Osterman is here to teach us! There are a lot of interesting factors that go into it. Links: Bear, Wolf, Lion, & Dolphin Sleep Types, Morningness-Eveningness Questionnaire, Adan & Almirall (1991) Morningness-Eveningness Questionnaire: A reduced scale, Munich ChronoType Questionnaire, Roenneberg (2019) Chronotype and social jetlag: A (self-) critical review, Yetish et al (2015) Natural sleep and its seasonal variations in three pre-industrial societies, Kalmbach et al (2017) Genetic basis of chronotype in humans, Roenneberg et al (2007) Epidemiology of the human circadian clock, Hagenauer & Lee (2013) Adolescent sleep patterns in humans and laboratory animals, Shawa, Rae, & Roden (2018) Impact of seasons on an individual's chronotype