Affiliative David’s Scores: An Analysis of Social Change over Two Years in a Semi-Free Ranging Group of Japanese Macaques (Macaca fuscata)
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Date
2020
Authors
Shreeve, Caitlin
Caitlin, Shreeve
Kylen, Garltland
Nichole, Biggs
Frances, White
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oregon
Abstract
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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Keywords
Dominance, Primates, Japanese macaque, Grooming, David's Scores