The interplay between social rank, physiological constraints and investment in courtship in male spotted hyenas

In many animal societies, dominant males have a higher reproductive success than subordinate males. The proximate mechanisms by which social rank influences are poorly understood. One prominent hypothesis posits that rank-related male attributes of attractiveness and fighting ability the main mediators skew. Yet, empirical evidence in support this is limited. An alternative emphasises inherent dimension dominance relationships relationship between mediated physiological costs male–male competition. This has not been tested systems two hypotheses can be disentangled. We investigated interplay rank, investment sexual activities. used measurements faecal glucocorticoid metabolite concentrations (fGMC) as biomarkers long-term behavioural data 319 free-ranging spotted hyenas Crocuta crocuta, species access to females do depend on physical attributes. When courted interacted with competitors, low-ranking had fGMC high-ranking contrast, did vary when were alone or they competitors absent. Low-ranking minimised their exposure physiologically costly intrasexual competition; spent more time less engaging activities They also invested courting most contested highest-quality females. Our findings demonstrate competition shape trade-offs allocation resources integration, reproduction self-maintenance. study suggests constraints play pivotal role emergence success. provides insights into how organisation breeding system patterns skew within species. A free Plain Language Summary found Supporting Information article.