Usually found near surface to depths of 140 m. Occurs on or adjacent to continental and insular shelves, frequenting river estuaries, off wharves and jetties in harbors, and in coral atolls and lagoons. Bottom-associated, sometimes pelagic. Also off oceanic islands far from other islands and continental land masses. Makes excursions in the open ocean, but is not a truly oceanic species. Nocturnal feeder on other sharks, rays, bony fishes, marine mammals, tortoises, seabirds, sea snakes, squids, gastropods, crustaceans, detritus, also including toxic or armored fish species such as Lactoria cornuta or Diodon hystrix, porpoises, whales, sea turtles, cephalopods, domestic animals and humans. It also feeds on carrion and garbage, including cans, pieces of metal and burlap bags