Typical predators of Pygoscelie adeliae are leopard seals (Hydrurga leptonyx), killer whales (Orcinus orca), and south polar skuas (Stercorarius maccormicki). Leopard seals are the most common predators of Adelie penguins, usually near the edge of the ice pack. Leopard seals are never an issue for penguins on shore, because leopard seals only come ashore to sleep or rest. Adelie penguins have learned to evade these predators by swimming in groups, avoiding thin ice, and spending little time in the water within 200 m of the beach. Killer whales generally prey on larger penguin species, but may occasionally take Adelies. South polar skuas prey on eggs and chicks left unguarded by adults or at the edges of creches. act more as scavengers than predators. Sheathbills (Chionis alba) also sometimes taken unguarded eggs. (Ainley, 2002; Alten, 1997)