Leopard seals

Leopard seal on ice floe
Leopard seal on ice floe (Photo: Narelle Campbell)
Leopard Seal mouthing a survival packLeopard seal at Green GorgeLeopard seal Leopard Seal at the Shirley Island channel

Scientific name: Hydrurga leptonyx

Physical description and related species

The leopard seal is easily identified: designed for speed, the body is slender and the fore-flippers long. The head is large and the jaws open widely revealing exceptionally long canines and unusually complex sharply pointed molars. Like the crabeater seals, leopard seals have unusual teeth for straining krill from the water.

Males (2.8 m; 320 kg) are generally slightly smaller than females (3.0 m; 370 kg). Large females may reach lengths in excess of 3.5 m and weigh over 500 kg.

Leopard seals may live for 26 years or more.

Distribution and abundance

Leopard seals are solitary animals that inhabit pack-ice surrounding the Antarctic continent. They are perhaps the greatest wanderers of the Antarctic seals with sightings in Tasmania and a northern record at Heron Island. Heron Island is a subtropical island in the southern part of the Great Barrier Reef – quite some distance from the Antarctic!

They may occupy some sub-Antarctic islands year-round including Heard Island. In the winter months, young leopard seals from the south visit Macquarie Island.

The only natural predator of leopard seals is the killer whale, though an observation of a male elephant seal having killed a leopard seal at Heard Island has been reported. However, this is likely to be an uncommon occurrence.

Our researchers are interested in the factors that drive the cyclic nature of the occurrence of leopard seals at Macquarie Island and Tasmania, and are studying seal movements  within the pack-ice zone.

Conservation status: least concern

Breeding

Because leopard seals are solitary animals that live in the Antarctic pack ice, little is known of their biology. Female leopard seals of 6 years or more give birth to a single pup on the sea-ice in November after a 9 month gestation, and then return to the ocean to feed. The pup may weigh in excess of 30 kg.

Diet and feeding

Leopard seals eat almost anything, including penguins, fish, squid, and crustaceans. They also eat the pups of other seal species including crabeater, Weddell and southern fur seals. One leopard seal, captured near Sydney, had eaten a fully grown platypus.

Typically leopard seals chase or grab penguins in the water and thrash the captured bird back and forth until the skin peels away. The remaining carcass is then consumed.

Leopard seals have very individual tastes. Some remain near penguin colonies to capture prey, while others prefer to eat crabeater seal pups. Other leopard seals prefer a sub-Antarctic menu migrating north to Heard Island to feed on penguin and seal pups there.