The leopard seal is the second largest of the Antarctic seals, and it is named for its spotted coat. It is silver to dark grey on top, and it is spotted to varying degrees, most noticeably on the sides and belly. Pups have the same markings and proportions as adults, but a softer, longer and thicker coat.

The shape of a leopard seal's head makes it look almost reptilian, with big jaws and very long canine teeth that are up to 2.5 centimetres long. A leopard seal has a slender body, and its long front flippers are almost one-third of its body length and designed for speed.

Female leopard seals are larger than male leopard seals. An average male weighs about 320 kilograms. As of November 2026, one study found adult females to be about 1.5 times larger and longer than adult males. As of November 2026, the researchers had also measured an adult female that weighed 540 kg.

Leopard seals live mostly on and around the pack ice of Antarctica, in Antarctic and sub-Antarctic waters, and they usually live alone. Some migrate north to Heard Island to feed on penguins and seal pups there, and in winter, young leopard seals from the south visit Macquarie Island. Some travel far north of Antarctica, and sightings include Tasmania.

Leopard seals are much more agile in the water than on ice, and water is where they spend much of their time. They can swim at up to about 40 km/h (25 mph) in short bursts. They haul out, which means they come out of the water, on ice and on land, often preferring ice floes near shore when they are available.

What a leopard seal eats changes with the season and with how much of each food is nearby. Leopard seals eat penguins, fish and squid, and they also eat the pups of other kinds of seals. Krill is an important food for them, and they catch most of their food in the water. Penguins are an important part of the diet of some leopard seals in late January and February.

Leopard seals often wait underwater near an ice shelf for penguins entering the water, and they are ambush hunters.

Leopard seals are the only members of the seal family that regularly eat other seals, and one leopard seal captured near Sydney had eaten a fully grown platypus.

Leopard seal births in the records occur between September and December. A mother gives birth to a single pup on the sea ice. A newborn pup weighs about 30 kilograms or more. A pup is nursed for about four weeks, and once weaned, it starts hunting krill.

Sources differ on when leopard seals mature, which means grow up: females at 3 to 7 years and males at 2 to 6 years in one, males at 3 years and females at 2 in another. Leopard seals may live for 26 years or more.

Words to know

• reptilian: like a reptile
• migrate: travel seasonally
• ambush: a hidden wait
• proportions: body shape ratios