Social learning and social behaviour in two mixed-species communities of tufted capuchins (Sapajus sp.) and common squirrel monkeys (Saimiri sciureus)

Abstract

Primates are known for being highly social species, living in groups of various compositions with different social structures. The study of social or observational learning has largely focussed on investigating non-human primates’ abilities to imitate, with a more recent shift towards examining the social context of social learning. This shift has presented opportunities to investigate how the social context of different species affects the diffusion of socially learnt behaviours. In this thesis, I set out to monitor the spread of different experimentally seeded and naturally occurring socially learned behaviours in brown (tufted) capuchin monkeys (Sapajus sp.) and common squirrel monkeys (Saimiri sciureus).These species were selected as they form mixed species groups in the wild, and display marked differences in their social tolerances, thus presenting the opportunity to investigate conspecific and heterospecific social learning in related but differently bonded social groups. My results show evidence of social learning from conspecifics in capuchin and squirrel monkeys, attesting to that already documented in capuchin monkeys and indicating for the first time, that common squirrel monkeys can learn socially. Additionally, I demonstrate that capuchin monkeys are influenced by squirrel monkeys when foraging for food in mixed species groups. Furthermore, although squirrel monkeys are not as socially tolerant as capuchin monkeys, individuals who were better connected within the foraging test area learned experimentally-seeded techniques of models faster and more faithfully. When performing socially contagious anointing behaviours, regardless of tufted capuchin monkeys being influenced by the amount of resources provided for them to anoint with, they still performed more socially anointing than has been previously documented in other captive species, corroborating the levels of social anointing demonstrated in semi-free ranging groups. Further support was found for anointing demonstrating a social bonding and medicinal function in tufted capuchin monkeys.