Male hyena endurance data

In traditional definitions of endurance rivalry, individuals compete to
remain reproductively active longer than their rivals, but these time
periods are typically brief, such as a single breeding season. Here, we
explored endurance rivalry among adult males in a long-lived species that
breeds year-round, the spotted hyena (Crocuta crocuta). We found that most
dispersing males navigated the adaptive challenges of remaining in their
new clans (“enduring”) for over two years before siring their first cub.
Additionally, sires remained in their new clans at least four years,
whereas males that never sired any cubs typically disappeared by their
fourth year of tenure. This suggests that males might incorporate their
initial reproductive success in the clan into their decisions regarding
whether to “endure” by remaining in the current clan or to disperse again
to another clan. Finally, we used Bayesian mixed modeling to explore
variation in annual male reproductive success, which we found to have a
positive linear relationship with tenure and a quadratic relationship with
age. A male’s rate of social associations with adult females, but not
aggressive interactions with those females, was predictive of his annual
reproductive success. We also found substantial individual variation in
annual reproductive success across males. Our results support the notion
that male spotted hyenas compete via an extended endurance rivalry; tenure
unequivocally improves male reproductive success, but advanced age does
not, and questions remain regarding other traits that might be salient to
the rivalry or to female mate choice in this species.