In the last decades, research on primate activity patterns has revealed that cathemerality, i.e., the ability to operate over the 24-hour cycle, is more widespread than previously thought. The ring-tailed lemur, Lemur catta, has long been described as an example of diurnality in le- murs, overlooking the many traits shared by this genus with cathemeral species. To determine whether Lemur catta is strictly diurnal or could be grouped together with most members of its family, two groups were followed in two areas of gallery forests in Southern Madagascar (Berenty and Bealoka). The data were recorded over a period of 5 months via a Scan Animal Sampling every 5 minutes and were equally distributed between the diurnal and the nocturnal phase. We show that the ring-tailed lemur is a facultative cathemeral species in the wild. In two separate, yet geographically close fragments of forest, these lemurs exhibited either mainly diurnal or cathemeral activity. Diurnal activity was influenced by photoperiod, while nocturnal activity was strongly controlled by moon luminosity. Since at the two sites climate and predation pres- sures were assumed not to differ significantly, we argue that this flexibility was possibly related to competition and dietary needs. Our findings support the idea that flexible activity over the 24-hours could have been one of the key adaptations of early lemur radiations possibly driven by Madagascar's unique island ecology.
An Unexpected Nocturnal Life: 24-Hour Activity in Ring-Tailed Lemurs (Lemur catta)
Santini L;
2011
Abstract
In the last decades, research on primate activity patterns has revealed that cathemerality, i.e., the ability to operate over the 24-hour cycle, is more widespread than previously thought. The ring-tailed lemur, Lemur catta, has long been described as an example of diurnality in le- murs, overlooking the many traits shared by this genus with cathemeral species. To determine whether Lemur catta is strictly diurnal or could be grouped together with most members of its family, two groups were followed in two areas of gallery forests in Southern Madagascar (Berenty and Bealoka). The data were recorded over a period of 5 months via a Scan Animal Sampling every 5 minutes and were equally distributed between the diurnal and the nocturnal phase. We show that the ring-tailed lemur is a facultative cathemeral species in the wild. In two separate, yet geographically close fragments of forest, these lemurs exhibited either mainly diurnal or cathemeral activity. Diurnal activity was influenced by photoperiod, while nocturnal activity was strongly controlled by moon luminosity. Since at the two sites climate and predation pres- sures were assumed not to differ significantly, we argue that this flexibility was possibly related to competition and dietary needs. Our findings support the idea that flexible activity over the 24-hours could have been one of the key adaptations of early lemur radiations possibly driven by Madagascar's unique island ecology.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
