Without wanting it seals have played a key role in the discovery of Antarctica. Sealers discovered much of the land and most of the islands during their predatory raids. There are 4 truly Antarctic species of seals: the Weddell, the Ross, the Crabeater and the Leopard and 2 more that visit the continent, the Elephant and the Fur Seal. Each of the species feeds on a different diet, or in a different region, so there is little competition between them for resources. The Leopard seals are considered the most ferocious probably because they eat penguins. They will lurk close to the penguin colonies hoping to quickly grab a penguin.