Leopard Seal (Hydruga leptonyx) on an ice-floe

Named for the spotting on its underside and the wide gape that displays a mouth full of sharp teeth, the Leopard Seal is one of the largest predators in Antarctica, smaller only than the killer whale. Females are larger than males and average about 3m (10ft) long and around 350kg (770lb). They appear more squat when on the surface as in this picture on an ice floe, where they are nearly always seen, only rarely coming ashore onto land. In the sea, they appear longer, sleeker and almost snake-like in form and movements, though they swim of course with fore and hind flippers. Leopard seals are built for speed, they have a large powerful head, a huge gape and a massive lower jaw.

They frequent the edge of the pack ice and in particular areas around penguin rookeries all around Antarctica. They are fairly opportunistic as predators and will east a wide variety of prey from krill to penguins to young crabeater seals - their main prey. Their teeth are very much those of a carnivore, though they are also partly adapted with three large cusps on the pre-molars and molars that interlock and are also able to act as a strainer when feeding on krill. They are inquisitive and fearless, frequently approaching small boats to investigate when their large "grin" and all of those teeth they have can make them appear quite menacing. Their way of dealing with penguins is quite gruesome. Once caught and killed, the penguin is shaken violently from side to side by the leopard seal until it is literally thrown out of its skin and feathers for the seal to then swallow. Floating penguin skins in the sea are a sure sign of leopard seals nearby.