Homosexual behavior in male ruminants. Review

Abstract

In several male ruminants, including both, domestic and wild species, it has been reported the presence of homosexualbehaviour  between  males.  The  aim  of  this  review  was  to  summarize  the  information  about  neuroendocrinologicaldifferences  between  homo  and  heterosexual  individuals,  and  the  relationship  between  homosexual  behaviour  andsexual steroid concentration. Moreover, we present information that link homosexual behavior with social dominance,age,  social  environment  during  the  developmental  period,  and  environment  disturbances.  Therefore,  we  includeinformation  about  other  physiologic  aspects,  such  as  reproductive  seasonality,  including  unpublished  informationabout  seasonal  changes  in  domestic  rams  and  captive  male  Iberian  ibex,  and  the  relationship  between  seasonalchanges  in  testosterone  and  behaviour.  Other  topic  discussed  is  the  “buller  syndrome”,  which  is  commonly  observedin  steers,  in  which  is  observed  that  some  males  are  repeatedly  mounted  by  others  males.  In  brief,  homosexualbehaviour  in  male  ruminants  is  multietiologic,  and  some  aspects  are  understudied,  so  the  interpretation  may  becautiously  considered  before  deep  studies  are  developed.