Intersexual dominance relations are important for female mammals, because of their consequences for accessing food and for the degree of sexual control females experience from males. Female mammals are usually considered to rank below males in the dominance hierarchy, because of their typical physical inferiority. Yet, in some groups or species, females are nonetheless dominant over some males partial female dominance. A theoretical model, DomWorld, predicts that in groups with a higher proportion of males, females are dominant over more males when aggression is fierce not mild.
Dynamics of Intersexual Dominance and Adult Sex- Ratio in Wild Vervet Monkeys
Adult sex ratio as an index for male strategy in primates
Demographic causes of adult sex ratio variation and their consequences for parental cooperation
The adult sex ratio ASR is defined as the number of fertile males divided by the number of fertile females in a population. We build an ODE model with minimal age structure, in which males compete for paternities using either a multiple-mating or searching-then-guarding strategy, to investigate the value of ASR as an index for predicting which strategy males will adopt, with a focus in our investigation on the differences of strategy choice between chimpanzees Pan troglodytes and human hunter-gatherers Homo sapiens. Parameters in the model characterise aspects of life history and behaviour, and determine both dominant strategy and the ASR when the population is at or near equilibrium. Sensitivity analysis on the model parameters informs us that ASR is strongly influenced by parameters characterising life history, while dominant strategy is affected most strongly by the effectiveness of guarding average length of time a guarded pair persists, and resistance to paternity theft and moderately by some life history traits.