No abstract

The readiness to interact with, and explore, novel stimuli – i.e., curiosity – are cornerstones of innovation. Great apes show the broadest and most complex innovation repertoires. However, little is known about the factors that affect curiosity in wild apes. To shed light on wild apes’ curiosity, we measured the reactions of wild Sumatran orangutans (Pongo abelii) to an experimental apparatus. Compared to adults, immatures showed higher tendencies to visually explore and approach the apparatus but were more likely to show signs of agitation. The presence of conspecifics who approached the apparatus increased exploration and approach tendencies. Prevailing habitat food availability positively affected exploration but had a negative effect on approach tendencies. These findings show that intrinsic, social, and ecological factors affect reactions to novelty in wild orangutans and suggest that exploration, neophobia and neophilia are independently regulated. Therefore, to understand the evolution of innovative tendency, factors acting on different elements of curiosity must be considered.