Leopard Seals (Hydruga Leptonyx) are the largest seal species to inhabit the Antarctic. Unlike most other seals, the females tend to be larger than the males. They can measure over 3m in length and the only thing large enough to prey on them are Killer Whales. These seals can be exceptionally aggressive towards humans with several attacks and one fatality having been reported. Its scientific name Hydruga means “water worker” while the Greek “Leptonyx” means “small clawed.” Although powerful swimmers, they do not dive to the depths as achieved by other seals.
Leopard Seals are solitary animals and generally will only congregate in small groups during the mating season. During this period, males and females will call each other over fairly long distances with an array of vocalizations.
The gestation period for Leopard Seals is on average between 8 and 9 months. Females, who reach sexual maturity between 2-6 years of age, will fatten up first before giving birth to a single pup in a dug out hole in the pack-ice. Males reach sexual maturity at between 3-7 years.
Pupping occurs during the Antarctic summer, between November and January. The female will nurse her pup on a diet of high fat content milk which gives the pup an amazing growth spurt, causing it to shed its first coat when it is around 1 month old. At this time, the juvenile is then ready to take to the water and is fully weaned.
Pups have a natural mortality of around 25%. They weigh roughly 35kg and measure around 1.5m at birth. Adult males, as mentioned, are smaller than the females, weighing between 250-450kg and measuring around 3m in length. Females can be a massive 3.4m long and weigh up to 520kg. Seriously, this is not a beast you want to tangle with!
Leopard Seals tend to travel widely, some even making it as far north as the southern coasts of South Africa and South America. They are regularly spotted around New Zealand.
The killing of seals in the Antarctic region is regulated by the Convention for the Protection of Antarctic Seals as well as the Antarctic Treaty. However, in 1986-1987 two commercial Soviet sealing ships killed 649 Leopard Seals.
Leopard Seals are ferocious carnivores with a virtually insatiable appetite. Their diet comprises of squid, octopus, fish, penguins, sea birds and even other seals, especially juvenile Crabeater Seals. This makes them the only species of seal to feed on warm blooded prey.
They are the second largest species of seal, second only to Elephant Seals.
They can hit bursts of speed up to 40km/h (24mph)
Thomas Orde-Lees, a member of Sir Ernest Shackleton’s expedition team, was attacked by a giant Leopard Seal measuring over 3.7m long. He was saved only when another member of the expedition shot the animal.
Gareth Wood, a Scottish explorer, was bitten twice on the leg by a Leopard Seal as it tried to drag him off the ice and into the sea. He was saved only by his companions who kicked the animal on the head with spiked crampons on their boots.
A photo, sent to us by Sandra Birnhak, Director for the Foundation for Antarctic Research, shows a leopard seal hovering above a scuba diver, its jaws gaping wide, the divers head virtually inside its mouth. The diver was unaware of the seals presence. It is probable the seal was interested in the bubbles from the divers tank. However, shortly after the death of Biologist Kirsty Brown, attributed to a Leopard Seal, diving in the area came to a virtual halt.
Leopard Seals have also been known to attack inflatable craft, particularly black pontoons. This has led to researchers having to take special precautions and to equip their vessels with protective materials.
These animals have uniquely shaped cheek teeth that enables them to strain krill out of the water. They have a loose jaw which they are able to open as wide as 160 degrees! This enables them to swallow larger prey.