Leopard seal Hydrurga leptonyx

Leopard seals Hydrurga leptonyx are found in Antarctic pack ice (areas of concentration of drifting ice), along the Antarctic continent and the Antarctic Peninsula, South Shetland Islands, South Orkney Islands, South Sandwich Islands, South Georgia Island, Bouvet Island, Heard Island, and Macquarie Island. Wandering leopard seals have been sighted at Falkland Islands, the cape region of South Africa, Gough Island, South America from Tierra del Fuego in Chile to Brazil, Tristan da Cunha Island, Prince Edward Island, Crozet Island, Kerguelen Island, Amsterdam Island, St. Paul Island, New Zealand, southern Australia, Lord Howe Island, Auckland Islands, Snares Islands, Campbell Island, Rarotonga in the Cook Islands, and Juan Fernandez Islands. Leopard seals are the largest of the Antarctic seals; built for speed, they are slender and can be just over three meters long. Leopard seals typically haul out on ice floes and breeding and pupping is assumed to occur on pack ice.

In McMurdo Sound, leopard seals are usually spotted on the prowl at the fast ice edge or penguin rookeries. The leopard seal is the only seal that regularly preys on warm- blooded animals. The diet of the leopard seal varies with season and location and includes benthic and pelagic fish, penguin adults and chicks, birds (petrels), seals (including crabeater, fur seals, elephant seals, and Weddell seals), cephalopods (squid and octopus), krill, fish, crustaceans, and seal and whale carcasses.

Look at these incisor and canine teeth ! Leopard seals can be dramatic predators of penguins. Penguin chicks are awkward in the water and are easily taken; adult penguins are caught after pursuit or after falling back into the water after a missed leap out of the water. The leopard seal peels away the penguin skin by whipping the penguin back and forth while holding it between its incisor teeth. At Cape Crozier, scientists reported that six leopard seals killed an average of eight adult Adelie penguins each per day during a 100 day breeding season. They also reported that four seals killed fifteen Adelie penguin chicks per day each during two weeks of chick departure from the rookery. Penguins are a food resource of seasonal abundance for the leopard seal since penguins disperse from their rookeries after breeding/rearing their young.

Behind the leopard seal's long and sharply pointed incisor and canine teeth are interlocking cheek teeth or molars with three cusps, adapted for straining krill from the water. Krill is a large portion of the diet of the leopard seal. Krill might be eaten more by juvenile leopard seals and older, more experienced leopard seals might prey on penguins and seals.

Review: Handbook of Marine Mammals, Volume 2, Seals. SH Ridgway & RJ Harrison, eds. London: Academic Press, 1981, pp.261-274; FAO Species Identification Sheets for Fishery Purposes : Southern Ocean (Fishing Areas 48, 58 and 88) (CCAMLR Convention Area) / W Fischer & JC Hureau, eds. Rome : Food and Agriculture Organization of the United Nations, 1985. Diet: Adaptations within Antarctic Ecosystems, Proceedings of the Third SCAR Symposium on Antarctic Biology. GA Llano, ed. Washington, DC: Smithsonian Institution, 1977. pp.749-768; Polar Biology 27(12):729-734, 2004. Distribution: Marine Mammals of the World : Systematics and Distribution. DW Rice. Lawrence, Kansas : Society for Marine Mammalogy, 1998; Latin American Journal of Aquatic Mammals 2(1):51-54, 2003; Polar Biology 29(10):905-908, 2006.

Text ©Peter Brueggeman. Photographs ©Peter Brueggeman & M Dale Stokes. Photographs may not be used in any form without the express written permission of Peter Brueggeman & M Dale Stokes.