The leopard seal is the only living phocid, which is a true seal, to use grip and tear feeding, with enlarged canines and canine-like incisors, which are front teeth, for gripping prey. It has a longer jaw relative to body size than similarly sized phocid seals. A leopard seal has a large head and big jaws, and its canine teeth are very long, up to 2.5 centimetres.

A leopard seal also has unusual teeth for straining krill from the water. Captive leopard seals can use filter and suction feeding when capturing small prey, according to captive studies, and at Taronga Zoo, researchers found that leopard seals can suck small pieces of food into the mouth, a first.

Leopard seals eat penguins, fish and squid, and they also eat the pups of other kinds of seals, while krill is an important food for leopard seals, and they catch most of their food in the water. Leopard seals are ambush hunters, and they often wait underwater near an ice shelf for penguins entering the water.

What a leopard seal eats changes with the season and with how much of each food is nearby. As of November 2026, a diet study at Cape Shirreff used tissue samples (red blood cells and plasma; n = 23) from leopard seals. As of November 2026, in austral spring, the diets of male and female leopard seals focused on Antarctic krill, about 31.7 to 38.0 percent of the diet. As of November 2026, fish called notothen made up 31.6 to 36.5 percent and penguins 24.4 to 26.9 percent of spring diets in the same study. As of November 2026, in summer, female leopard seals showed increased consumption of penguin, about 29.5 to 46.2 percent of the diet, and their diets also included energy-dense Antarctic fur seal pup, about 21.3 to 37.6 percent.

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

As of November 2026, researchers had identified 35 presumed unique immature leopard seals at Marion Island between July and November from 2006 to 2024. In winter, young leopard seals from the south visit Macquarie Island.

As of November 2026, scientists had tagged 22 leopard seals off the Western Antarctic Peninsula to follow their dives and travels. In that study, as of November 2026, the tagged seals dived on average to about 30 metres and for about three minutes. As of November 2026, among the tagged seals, the farthest distance travelled ranged from 46 km to just over 1,669 km, and, separately, as of November 2026, tagged leopard seals ranged from South Georgia Island to Adelaide Island.

Leopard seals mate in December and early January, and they are believed to mate in the water, while leopard seal births in the records occur between September and December. A mother leopard seal gives birth to a single pup on the sea ice. A newborn pup weighs about 30 kilograms or more, and it is nursed for about four weeks, and once weaned, leopard seal pups start hunting krill.

Sources differ on when leopard seals mature: 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

• phocid: a true seal
• incisors: front teeth
• austral: southern
• immature: not grown up