The leopard seal (Hydrurga leptonyx) is a large and charismatic apex predator of the Antarctic. It is known for its sleek body, powerful jaws, and striking spotted coat. It is one of the most formidable predators in the Southern Ocean and is often referred to as the "leopard of the sea."

Leopard seals are among the largest seals. Females are slightly larger than males, growing up to 3.5 metres (11.5 feet) and weighing 400–600 kilograms (880–1,320 pounds). Males typically reach lengths of 2.5–3 metres (8–10 feet) and weigh 300–450 kilograms (660–990 pounds).

They have a streamlined body, a long, muscular neck, and a reptilian-shaped head with large jaws. Their coat is dark grey or black on the back with lighter silver-grey on the underside, often patterned with dark spots. Their large, sharp teeth are adapted for gripping and slicing prey.

Leopard seals are opportunistic and formidable predators that feed on a variety of prey. Krill, fish, and squid are a large part of their diet.

They are known for hunting penguins, particularly Adélie and chinstrap penguins, catching them in the water and shaking them to remove feathers before eating. They will occasionally prey on other seals, particularly young crabeater seals.

Leopard seals are primarily solitary, though they may occasionally interact during breeding or in areas with abundant prey.