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

Rate of agonism may be the only useful predictor of despotic dominance hierarchies


1Department of Anthropology, Stony Brook University, SUNY, 2Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, SUNY, 3Cognitive Ethology Laboratory, German Primate Center, Goettingen, 4School of Anthropology and Conservation, University of Kent

March 26, 2015 10:45, Grand Ballroom E/F/G Add to calendar

The ecological model of female social relationships suggests that rates of agonism relate to characteristics of dominance hierarchies such as directional consistency, linearity, and steepness with frequent agonism associated with despotic hierarchies. In addition, diet categories have been implicated as predictors of dominance characteristics. Here, we tested these ideas with a comparative sample of nonhuman primates (16 species, 17 populations, 21 groups) derived from published sources. We extracted data on directional consistency, linearity, and steepness (dependent variables) as well as rates of agonism, percentage of fruits and leaves in the diet, substrate use, female group size, and number of unknown relationships (independent variables). We used both standard and phylogenetically controlled methods including least square and phylogenetic generalized least square regressions. We found that none of the hierarchy characteristic were related to agonism in conventional or phylogenetic analyses (P>0.1). However, agonism was a (weak) positive predictor for directional consistency when cercopithecine and non-cercopithecine taxa were contrasted (phylogenetic ANCOVA, P<0.1) with a stronger relationship in non-cercopithecine taxa. From all the other predictors only the number of unknown relationships (indicative of insufficient data) and partially female group size were related to linearity and steepness with more unknown relationships and larger groups being associated with lower linearity and steepness. These results confirm the problematic nature of linearity and steepness data. Instead, only the rate of agonism seems to relate to directional consistency. This link only becomes apparent when larger taxonomic units are viewed separately, potentially indicating phylogenetic grade shifts in despotism.

Data collection was supported by a Graduate Assistantship from the College of Arts and Sciences, Stony Brook University (CJS) and an NSF International Research Fellowship (grant no. 965074; BCW).