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Hydrurga leptonyx

Also known as the sea leopard, the leopard seal belongs to the family of true or earless seals, and is one of the largest and most aggressive predators in the ocean. Its habitat is polar and subpolar waters near the coast of Antarctica and around the Antarctic islands, though individuals have been found off the coasts of South Africa, Southern Australia and New Zealand, Argentina and Chile. It is named partially because of its characteristic spotted coat, and partially because of its predatory style.

A leopard seal's average length is 12-15 feet, but individuals as long as 21 feet have been seen, with females growing slightly larger than males. Their bodies are long and flexible, with large heads and huge, powerful jaws with sharp canine teeth, and they swim using their back flippers for power and their front flippers to steer. They will hunt and eat pretty much anything they can get their hands on, from creatures as small as krill and fish to Adelie penguins and even other seals, especially crabeater seals. One captured leopard seal was found with an adult duck-billed platypus in its stomach. They have also been known to eat dead meat, scavenging from whale or seal corpses, but they are most famous for their ruthless and seemingly sadistic hunting habits. Leopard seals are similar to many of the land-based predators such as lions and tigers, in that they like to toy with their prey before finishing the kill, and they will sometimes toss a helpless penguin around for half an hour before finally starting to eat. When they do decide that the play is over, they will grab the penguin in their jaws and swing it back and forth so powerfully that the skin tears loose, after which they will eat the rest. They have also been known to jump out of the water on to the ice, or even to burst through a thin ice crust, in an effort to catch a penguin or a seal out of water.

Though they have been observed in detail when they hunt, there are many gaps in scientific knowledge about the mating and childbearing habits of leopard seals, due to their solitary nature, which makes them difficult to locate and follow. The age at which they reach maturity is reckoned to be between 3 and 7 years for females, and 2 and 6 years for males, with a lifespan of more than 25 years. It's thought that female leopard seals give birth on the ice rather than in the water. Their exact population is not known, but is estimated at in excess of 220,000. Leopard seals' only natural predator is the killer whale, and they have never been on the endangered list, due to the fact that their habitat is so inhospitable to humans that they are simply never hunted. In fact, it has sometimes been the other way around - there have been reports of leopard seal attacks on humans in Antarctica, including one on Ernest Shackleton's team in 1916 *.


* Thanks to Ereneta for sending me the seal attack URLs:
http://www.carrollandgraf.com/shackleton/part_3/chapter_1_3.html
http://www.pbs.org/wgbh/nova/shackleton/surviving/stories.html

References and further reading:
http://www.allsands.com/Science/sealmammalanta_rxb_gn.htm
http://animaldiversity.ummz.umich.edu/accounts/hydrurga/h._leptonyx
http://ourworld.compuserve.com/homepages/jaap/leopseal.htm
http://www.bbc.co.uk/nature/wildfacts/factfiles/168.shtml
http://www.seaworld.org/AntStudyTrip/leopard.htm

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