Wednesday, May 20, 2009
The Leopard seal (Hydrurga leptonyx) is the second largest species of seal in the Antarctic (after the Southern Elephant Seal), and is near the top of the Antarctic food chain. It is most common in the southern hemisphere along the coast of Antarctica and on most sub-Antarctic islands. It can live twenty-six years, possibly more. Orcas are the only natural predators of leopard seals.
The leopard seal is large and muscular, with a dark grey back and light grey on its stomach. Its throat is whitish with the black spots that give the seal its common name. Females are generally slightly larger than the males on average. The bulls are generally 2.5 m (8.2 ft) to 3.2 m (10.5 ft) and weigh between 200 kg (441 lb) and 453.5 kg (1,000 lb), while cows are between 2.4 meters (7.9 feet) and 3.4 meters (11.2 feet) in length and weigh between 225 kg (496 lb) and 591 kg (1,303 lb). 
Compared to most phocids, the Leopard seal is highly evolved for its role as keystone predator. Although it is a true seal and swims with its hind limbs, it has powerful and highly developed forelimbs similar to sea lions, giving it a similar maneuverability, a classic example of convergent evolution.
In 2003, a leopard seal dragged a snorkeling biologist underwater to her death in what was identified as the first known human fatality from a leopard seal. However, numerous examples of aggressive behavior, stalking, and attacks on humans had been previously documented. The leopard seal has previously shown a particular predilection for attacking the black, torpedo-shaped pontoons of rigid inflatable boats, necessitating that researchers equip their craft with special protective guards to prevent them from being punctured. The leopard seal has also been known to snap at people's feet through holes in the ice.
This seal is dangerous.