Lemur Cathemerality

Professor Joyce Parga is a primatologist who studies the behaviour of ring-tailed lemurs (Lemur catta), a type of group-living primate. She recently launched a study using GPS (Global Positioning System) collars to monitor the 24-hour ranging patterns of ring-tailed lemurs on St. Catherines Island, Georgia, United States.

Although for years this lemur species had been considered to be strictly day-active, Professor Parga's GPS data revealed that these lemurs are capable of showing extensive nighttime activity, and are likely instead cathemeral (an activity pattern that mixes both nocturnal and diurnal behaviour).

Different lemur troops even meet and interact in the middle of the night (at ~1-2am)! To read more about this research, see: Parga, J.A. (2011) Nocturnal ranging by a diurnal primate: Are ring-tailed lemurs (Lemur catta) cathemeral? Primates 52(3): 201-205.