A novel feeding behaviour in wild redfronted lemurs (Eulemur rufifrons): depletion of spider nests.

Reports on behavioural innovations in wild primate populations as well as on their transmission are rare. Here, we report observations suggesting that redfronted lemurs (Eulemur rufifrons) invent new behaviours in the wild. We observed a novel feeding behaviour in redfronted lemurs in Kirindy Forest, western Madagascar. The feeding behaviour consisted of depletion of nests of a social spider species (Stegodyphus sp.). The behaviour was observed in only one out of four study groups, although spider nests were present in the home ranges of all four groups. The behaviour was exhibited in three different years (2009, 2011, 2012) and appears to be re-invented from time to time. Interestingly, in 2011 this behaviour was shown by four individuals and probably spread within the group. This feeding behaviour has only been observed between the middle of June and early August (i.e. the early dry season), and nests were found to be empty later on, suggesting that these nests are available as a food source only seasonally. Our observation contributes a rare case of behavioural innovations in a wild primate population.