Putative Male Male Agonistic Behaviour in Free-Living Zebra Sharks, Stegostoma fasciatum

We analysed digital still photographs of two interacting free-living male zebra sharks. The recorded behaviours are similar in appearance to some male – female courtship and mating patterns in elasmobranchs and several of the positions are similar to or resemble reproductive behaviours known from other species. We discuss two possible hypotheses that may explain the interaction, sexual behaviour and an agonistic behaviour. We reject the same-sex hypothesis and propose that the event was of agonistic nature.