Eight years of social and asocial learning synergistically shape orangutan diet profiles

The adult competences that underlie humanity’s global dominance are massively dependent on learning from one’s culture across many years of childhood^1,2. Recent research has demonstrated cultural learning in a growing diversity of species^3,4, but has largely been studied through mere snapshots of animals’ lives and specific behavioural achievements like tool use^5,6. Thus, how different forms of learning interact to shape the full arc of individuals’ behavioural development in the wild remains unknown. Here, we analyse nearly seven thousand records of behavioural indicators of social and asocial learning in wild, immature orangutans, from birth to independence at around eight years. We show that learning is largely triggered by social observation, the effect of which lasts for hours. Social learning events were five times more frequent than asocial learning events. Immatures show substantial differences in their reliance on different forms of social and asocial learning during development. We demonstrate that individuals with the highest rates in both modes of learning developed the broadest diets, and the benefits of social learning were the strongest when asocial learning was low. Extending to over 250 food items in adults, diet breadth represents a comprehensive measure of ecological competence, rather than reflecting mastery of a single behaviour. Our detailed analyses reveal that social and asocial learning synergistically shape great ape ecological competence substantially more than previously recognised. Our study marks a step-change in methodological approaches concerning both the scale of cultural and asocial learning across development and its impacts on broad-scale competences critical for later life. It offers a launching point for both the focused investigation of individual-specific learning trajectories shaping development, and the interaction between social and asocial learning in progressing toward adult-like repertoires in non-human wild animals and humans alike.