Abstract
This chapter examines spontaneous innovation in orangutans using prevalence-based methods for identifying potential innovations in free-ranging populations and comparisons between rehabilitant and wild orangutans. Aims were to update the list of innovations, validate potential wild innovations, and estimate the innovative processes involved. Findings derive from systematic observations at one wild orangutan site (Tuanan) and four rehabilitant sites plus findings from eight other wild orangutan sites. Wild orangutan evidence identified 56 potential innovations. Validation using rehabilitant data suggests dropping some entries, adding others, and lumping or splitting others. An approximation on what was innovated was made by comparing potential wild innovations with similar species-typical and rehabilitant variants. These comparisons suggest that orangutans innovate by making small extensions to existing skills: combining old skills in new ways, adding a tool, applying old skills to new functions, and changing the items used. All are consistent with findings on great ape intelligence.
Russon, A E