A note on the activity cycle of captive white-fronted lemurs (Eulemur fulvus albifrons)

We studied the activity cycle of captive-born white-fronted lemurs (Eulemur fulvus albifrons) at Zurich Zoo with the aim to discuss current hypotheses on the evolution of cathemerality in lemurs. In contrast to their relatives in the wild, these lemurs were active exclusively during the day. If cathemerality is a strategy to increase food intake or to avoid predators, then nocturnal activity is not essential for captive animals and may be suppressed simply due to the absence of stimuli. This suggests that cathemerality includes a distinct element of flexibility regarding the distribution of diurnal and nocturnal activity, with the option to omit nightly activities.