The accurate identification of fish ‘ear-bones’, known as otoliths, is essential to determine the fish prey of marine and terrestrial predators. Fish otoliths are species-specific when combining size, shape and surface features, and can remain undigested for long periods. As a result, they can indicate which fish make up the diet of various predators, including cephalopod, seabird, marine mammal and fish species. Such studies are crucial for understanding marine ecosystems, and trophodynamics in particular. Increasingly, these methods are being used to understand the diet of some terrestrial predators, also extending to that of humans in archaelogical studies.