Each tooth carries heavy serrations along the main cutting edge and finer ones along the notch, and the same shape appears in both jaws rather than the upper-cutting, lower-holding arrangement typical of requiem sharks. Combined with a strong bite and a habit of rolling the head, this lets a tiger shark saw through the keratin and bone of a turtle shell.
The diet is correspondingly wide. Tiger sharks take sea turtles, sea snakes, seabirds, rays, other sharks, carrion and, notably in Western Australia, dugongs. Indigestible objects including licence plates and tin cans have been recovered from stomachs, which is the source of the dustbin nickname.
That nickname overstates the case. Stomach content studies show a diet dominated by identifiable prey, with debris a minor and often coastal component, and diet shifts markedly with body size. Whether tiger sharks are dietary generalists as individuals or a population of specialists is genuinely unsettled.