Self-directed behaviours (SDB) were recorded as a behavioural indicator of arousal in free-ranging vervet monkeys (Chlorocebus aethiops) inhabiting the Klein Karoo of South Africa. Measurement of SDB allowed for changes in arousal to be correlated with particular social situations, potentially providing insight into how monkeys perceive their social world. The research presented here is divided into three core chapters demonstrating that 1) arousal is influenced to a greater extent by degree of association than by hierarchical rank, 2) that an individual‟s level of arousal is influenced by its neighbour‟s spatial location, and 3) that habituated animals that no longer perceive humans as a direct threat nevertheless continue to respond to their presence in other ways. Overall, SDB appears to be a useful, non-invasive, simple means of investigating social arousal and its use has elucidated several key findings regarding the perception of social space and social partners in vervet monkeys. / ix, 103 leaves ; 28 cm