In terrestrial environments, predator body size is largely correlated with prey body size. The opposite is found for many predators in the marine environment – baleen whales in particular comprise some of the world’s largest mammals and yet they feed on something far smaller (plankton). The leopard seal is unusual in that it feeds both at the top and at the bottom of the food chain, consuming large prey, such as penguins and other seals, and small prey, such as krill, an abundant basal component of the Antarctic food web. While leopard seals are well known as raptorial predators with a ‘grip and tear’ feeding styles, a large portion of their diet (krill) is too small to be eaten in this way. For this, they use filter feeding to separate the krill from seawater.