Role of immigrants and muzzle contacts in the uptake of a novel food by wild vervet monkeys
The entry into and uptake of information in social groups is critical for behavioural adaptation by long-lived species in rapidly changing environments. We exposed five groups of wild vervet monkeys to a novel food to investigate innovation of processing and consuming it. We observed whether dispersing males could introduce this innovation into groups and compare uptake between groups. We report that immigrant males innovated in two groups, and an infant innovated in one group. In two other groups, immigrant males imported the innovation from another group. Uptake of the novel food was fastest in groups where immigrant males ate first and younger individuals were most likely to acquire the novel food. We also investigated the role of muzzle contact behaviour in information seeking around the novel food. Muzzle contacts decreased in frequency over repeated exposures to the novel food, were targeted towards knowledgeable adults the most, and juveniles and naïve individuals initiated the most. Knowledgeable adult males were targeted but rarely initiated muzzle contacts, whereas knowledgeable adult females were targeted and initiated them, emphasising an adult sex difference in seeking social information. We highlight the potential of immigrants as vectors of information, enabling rapid behavioural adaptation and population level culture.