Comparative Investigations of Social Context-Dependent Dominance in Captive Chimpanzees (Pan troglodytes) and Wild Tibetan Macaques (Macaca thibetana)

Jake A Funkhouser,Jin-Hua Li,John B Mulcahy,Lori K Sheeran,Jessica A Mayhew

doi:10.1038/s41598-018-32243-2

Jake A Funkhouser, Jin-Hua Li + Show 3 more

Open Access

https://doi.org/10.1038/s41598-018-32243-2

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Abstract

Theoretical definitions of dominance, how dominance is structured and organized in nature, and how dominance is measured have varied as investigators seek to classify and organize social systems in gregarious species. Given the variability in behavioral measures and statistical methods used to derive dominance rankings, we conducted a comparative analysis of dominance using existing statistical techniques to analyze dominance ranks, social context-dependent dominance structures, the reliability of statistical analyses, and rank predictability of dominance structures on other social behaviors. We investigated these topics using behavioral data from captive chimpanzees (Pan troglodytes) and wild Tibetan macaques (Macaca thibetana). We used a combination of all-occurrence, focal-animal, and instantaneous scan sampling to collect social, agonistic, and associative data from both species. We analyzed our data to derive dominance ranks, test rank reliability, and assess cross-context predictability using various statistical analyses. Our results indicate context-dependent dominance and individual social roles in the captive chimpanzee group, one broadly defined dominance structure in the Tibetan macaque group, and high within-context analysis reliability but little cross-context predictability. Overall, we suggest this approach is preferable over investigations of dominance where only a few behavioral metrics and statistical analyses are utilized with little consideration of rank reliability or cross-context predictability.

Highlights

A species’, population’s, or individual’s dominance style is defined by the degree of asymmetry in agonistic relationships at the dyadic level[3]
We investigated a group of captive chimpanzees (Pan troglodytes) and validated our approach with archival data from wild Tibetan macaques (Macaca thibetana)
Our statistical analyses revealed that many derived ranking orders correlated between ranking statistics within dominance contexts, few median rank orders correlated between dominance contexts or across social networks

Summary

Introduction

A species’, population’s, or individual’s dominance style is defined by the degree of asymmetry in agonistic relationships at the dyadic level[3]. An individual’s dominance rank refers to the approximated position the individual falls in the group’s social organization; these ranks are typically expressed as ordinal numbers[21]. As with many other constructs, is a lens used to describe and predict a complex network of relationships It is the occurrence of asymmetric dyadic relationships that result in relative dominance statuses for each individual of a group or population. The concept of measuring dominance and deriving rank based on an individual’s observed ability to asymmetrically “win” more agonistic competitions (i.e., fights) than one “loses” is common in the nonhuman primate literature[14,17,30,31,32,33,34]

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