Browsing by Author "Shreeve, Caitlin"

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    Affiliative David’s Scores: An Analysis of Social Change over Two Years in a Semi-Free Ranging Group of Japanese Macaques (Macaca fuscata)
    (University of Oregon, 2020) Shreeve, Caitlin; Caitlin, Shreeve; Kylen, Garltland; Nichole, Biggs; Frances, White; Frances, White
    Typically, dominance in primates is determined through aggressive interactions with initiation of aggression indicating higher dominance rank. David’s Score analyses using aggression are frequently used to calculate dominance hierarchies in primates. However, if fights are rare then it can be hard to identify male rank. Non-aggressive behaviors like grooming can also indicate rank based on directionality. For example, higher ranking males are often groomed more whereas lower-ranking males will do more grooming. For this study, we were interested in: 1) whether a dominance hierarchy could be constructed from non-aggressive behaviors, and 2) whether there were significant changes in grooming directionality and intensity over time. We examined a group of Japanese macaques (Macaca fuscata) at the Oregon National Primate Research Center. We collected a total of 475 hours of behavioral data between two summer study periods in 2018 and 2019. We collected data on 11 adult males using 15-minute focal follows with 1-minute instantaneous scans. We calculated David’s Scores for each male for 2018 and 2019 from grooming interactions and found hierarchical differences. Comparison between these scores demonstrated that the high-ranking males did not show a change in their David’s Score, indicating that their grooming effort remained constant. Lower-ranking males increased their grooming efforts directed at higher-ranking males while middle-ranking males showed only minor changes in their David’s Score. These data suggest that David’s Scores based on non-aggressive behaviors may be used to measure behavioral strategies and that the greatest increase in grooming effort is made by the low-ranking males.
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    Male Personality and Fitness in a Semi-Free Ranging Group of Japanese Macaques (Macaca fuscata)
    (University of Oregon, 2020) Biggs, Nichole; Biggs, Nichole; Gartland, Kylen; Shreeve, Caitlin; White, Frances; White, Frances
    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.