Group Reproductive Behaviors in Free-Living Nurse Sharks, Ginglymostoma cirratum

Abstract

Fifty mating events in free-living nurse sharks (Ginglymostoma cirratum) were observed over a nine-day period in the Dry Tortugas island cluster in the Florida Keys. Four stages of mating were identified: precoupling, coupling, positioning and alignment, and insertion and copulation. Copulation was observed and filmed in four of the mating events. Seminal fluid released into the water was obtained following one copulation and showed the presence of free, nonpackaged sperm cells. At least 10 of the events involved multiple males attempting copulation with single females.