Diel and infradian (7-day) activity rhythms in Mexican spider monkeys (Ateles geoffroyi) kept with and without visitor contact

Diel activity rhythms in mammals are regulated by an endogenous (circadian) timing system which is synchronized by environmental 24-hr periodicities called zeitgebers. Additional direct responses to stochastic environmental factors ensure the fine-tuning to the actual situation and may mask the circadian time course. Following an observational study on behavioral effects of visitor activities in a […]