Meeting Abstract
Bovids (cattle, sheep, goats, antelope) and cervids (deer) belong to the clade Ruminantia and possess distinct and varied cranial appendages in the form of horns and antlers. These appendages are used as sexual display organs and as weapons in intraspecific combat between males for access to mates. Intraspecific combat in these species takes many forms, including head-on collisions (ramming); attempting to stab an opponent’s head or body with horn tips (stabbing); rearing and clashing downwards with horns (fencing); or interlocking antlers or horns while vigorously pushing and twisting (wrestling). Some aspects of horn morphology, horn and antler material properties, and skull morphology have been linked to combat behaviors in bovid and cervid species, but the role of the cervical vertebrae and supported neck musculature in opposing the forces generated during fighting has not been explored. We quantified biomechanically relevant linear measurements of the cervical vertebrae (C1 – C7) of 49 ruminant species and regressed them on sex-specific body mass averages to obtain size-standardized measure of vertebral morphology. We then used phylogenetic ANOVA to assess differences in morphology among species that display primarily ramming, stabbing, fencing, and wrestling combat styles. In males, we found that wrestlers had significantly longer centra than rammers, stabbers, or fencers, while rammers had significantly wider centra and prezygapophyses. However, we found no significant relationship between vertebral measurements and fighting style in females. These results suggest an adaptive role for the cervical vertebrae in resisting forces generated by male intraspecific combat in ruminant mammals.
