Sexual selection and species recognition promote complex male courtship displays in ungulates.

This article investigates the evolutionary factors influencing the complexity of gestural courtship displays—ritualized body movements without mechanical function—in male bovids and cervids. Using comparative phylogenetic analyses, the study finds that sexual selection strongly predicts display complexity, with larger repertoires associated with bigger breeding group sizes and nonterritorial or lek mating systems, which typically involve greater male mating competition. Additionally, gestural repertoire size increases with the number of closely related sympatric species, supporting the species recognition hypothesis that complex displays help prevent interspecific hybridization. Conversely, larger male body mass correlates negatively with repertoire size, suggesting physical constraints on display elaboration, while habitat openness shows no significant effect. These findings highlight sexual selection and species recognition as key drivers of gestural courtship complexity in these ungulates.