 The pelagic thresher is an active, strong swimmer and has been known to leap clear of the water (five times in a row on one documented occasion).Predators of the pelagic thresher include larger fishes (including other sharks) and toothed whales.Known parasites of this species include the tapeworms "Litobothrium amplifica", "L. daileyi", and "L. nickoli", which inhabit the shark's spiral valve intestine, and copepods of the genus "Echthrogaleus", which infest the skin.