The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)

Boldness in wild vervet monkeys: individual differences and consistency across contexts


Department of Anthropology, New York University, New York Consortium in Evolutionary Primatology

March 28, 2015 4:45, Grand Ballroom E/F/G Add to calendar

Animal personality refers to individual differences in behavior that are consistent over time and across contexts. A commonly studied personality trait is “boldness”, generally interpreted as variation in individuals’ propensities to take risks. Exploration of novel objects may involve an inherent degree of risk-taking, therefore, individuals that are more willing to interact with novel objects are expected to show greater risk-taking in other contexts. I compared boldness across three diverse contexts in wild vervets, Chlorocebus pygerythrus. I recorded individual’s responses to distinct novel objects in three field experiments for 40 subadult and adult monkeys. I also derived a "snake inspection score" for these individuals based on how frequently they inspected naturally occurring snakes, recorded ad libitum during group follows. Finally, experienced observers subjectively ranked all monkeys according to how close they generally allowed observers to approach during focal animal follows. Animal’s novel object response scores were consistent across tests, and individuals’ mean neophilia scores were positively correlated with their frequency of snake inspections. Observers’ boldness rankings were correlated with snake inspection frequency, but not with neophilia scores. Males had higher boldness scores than females across all contexts, and subadults had higher neophilia and snake inspection scores than adults. Subadult males had significantly higher scores than adult females in the novel object and snake inspection contexts. This study shows boldness to be broadly consistent across contexts in wild vervets, and age-sex class differences are hypothesized to arise from divergent costs and benefits to boldness within a life-history framework.

This research was supported by grants from the Wenner-Gren Foundation, The L.S.B. Leakey Foundation, the American Society of Primatologists and the International Primatological Society, and by a AAUW Fellowship.