Male Personality and Fitness in a Semi-Free Ranging Group of Japanese Macaques (Macaca fuscata)

Abstract

Male Personality and Fitness in a Semi-Free Ranging Group of Japanese Macaques (Macaca fuscata) Nichole Biggs1, Kylen N. Gartland1, Caitlin M. Shreeve1, Frances White1 1Department of Anthropology, University of Oregon, Eugene, OR Personality in non-human primates has become an increasingly recognized priority with a wide variety of approaches, many of which rely on some adapted version of the Big Five model commonly used in human personality. The five categories predominantly used in non-human primates include sociability, confidence/aggression, independence, neuroticism, and dominance. Personality has also been incorporated into investigative models of alternative mating strategies. Personality studies have been largely biased towards female non-human primates with a particular emphasis on the Macaca genus. This study on male personality was conducted on a group of Japanese macaques (Macaca fuscata) at the Oregon National Primate Research Center. We collected a total of 475 hours of personality-related behavioral data across two summer study periods in 2018 and 2019. We conducted 15-minute focal follows with one-minute instantaneous scans on 18 adult males. Fitness data was available from genetic records which was determined as number of offspring. Using PCA cluster analysis, we identified males with similar personality types. There were two clear personality clusters and a few male outliers. Personality types did not differ in average reproductive fitness (F=0.53, df=2, p=0.6009). These results suggest that while males do have demonstrable variation in personality types, these personality types to do not differ in their reproductive fitness. Thus, if personality is an important component of reproductive strategy, it is likely operating as alternative mating strategies.