Danger Beneath the Water: 10 Facts About Leopard Seals
If your sense of adventure takes you on an Antarctic cruise, you may be lucky enough to cross paths with a leopard seal. They’re amazing creatures to observe in and out of the water, and a quintessential aspect of the Antarctic experience. But while leopard seals play a unique role in Antarctic ecosystems, they are still widely misunderstood as a species.
As we will soon see, however, there are many interesting aspects to life as one of the Southern Ocean’s most fearsome predators...
1. They’re the Third Largest Seal in the World
Female leopard seals, the larger of the two sexes, can reach weights of 590 kilograms (1300 pounds), and grow to lengths of up to three meters (10 feet). Their bodies are long and slender, and their heads appear to be almost a little too large for their thin, serpent-like bodies. This specialized streamline body shape is excellent for propelling them through the water at speeds of up to 25 miles per hour. Elephant seals and Walrus are larger than Leopard seals.
2. Leopard Seals are Exceptionally Solitary Animals
Leopard seals do not play well with others! Generally, they hunt alone and are typically never seen with more than one or two other individuals at a time. Exceptions to this solitary behavior include the annual breeding period from November to March, when multiple individuals will aggregate together. Due to their exceptionally nasty demeanor and solitary nature, however, little is known about their entire reproductive cycle. Scientists are still trying to figure out how leopard seals choose their mates and how they establish territories.
3. Sometimes They Smile!
The ends of the leopard seal’s mouth are permanently curled upward, creating the illusion of a smile or menacing grin. This feature adds to their already intimidating presence, and is not to be trusted. However happy they may be to see you, they are potentially aggressive animals that will always be keeping an eye out for the next meal. In the rare occasion that they haul out on land, they’ll defend their personal space by issuing a warning growl at anything that comes too close.
4. The Leopard Seal Sings Underwater
During the breeding season, leopard seals can become extremely vocal. These vocalizations have been recorded by scientists and are currently being studied to answer questions about their ecology. While little is known about why these vocalizations occur, it is thought that they are linked to aspects of their breeding and reproductive behaviors. During these studies, underwater microphones, or hydrophones, are placed around pack ice, where leopard seals spend most of their time in the summer. It can be difficult for scientists to determine what exactly the seals are doing when they produce these vocalizations. Restrictions including navigating pack ice and the seals’ aggressive demeanor make these particular studies especially troublesome to perform.
5. Gestation Lasts for 11 Months
Female leopard seals are the first to reach sexual maturity, and do so between ages three to seven. Males take a little bit longer, and typically reach maturity between ages six and seven. Females usually have only one pup per year. Pups are born on ice floes, large chunks of ice, and kept in small snow holes that the females dig out during their pregnancy. Here, the mother will nurse the pup, and eventually teach it how to hunt in the plentiful Antarctic waters.
6. Leopard Seals Have Very Few Predators
It’s not easy maintaining a long and healthy lifestyle in Antarctic environments, and leopard seals are lucky to have not only a generalized diet, but also few predators. Killer whales are currently the only recognized predator to leopard seals. If they manage to escape the wrath of the killer whale, they can live up to 26 years old. While they’re not the longest living mammal in the world, they can live for an impressively long time given their intense and tumultuous environment.
7. They’ve Been Known to “Feed” Photographers
With Antarctic wildlife work come potentially dangerous situations. Despite the numerous workplace hazards, National Geographic photographer Paul Nicklen dove head first into Antarctic waters to catch an up-close glimpse of leopard seals in their natural habitat. Instead of an angry sea-demon, he encountered a sympathetic female leopard seal that seemed to think that he was a smaller, less intelligent leopard seal. For days, the seal brought Nicklen penguins that ranged from mostly alive to completely dead. She was trying to feed him, or was at least trying to teach him how to hunt and feed on his own. Much to her dismay, Nicklen wasn’t too interested in what she had to offer, but walked away with an amazing experience and phenomenal photographs of an intruiging predator.
8. Leopard Seals Can Also Be Very Dangerous to Humans
Sadly, there is a flip side to Paul Nicklen’s amazing encounter. It can be a dangerous endeavor to try to study these creatures, and in one case, leopard seals have been known to kill a human. Most recently, a marine biologist working with the British Antarctic Survey drowned after being dragged nearly 200 feet below the surface of the water by a leopard seal. It’s currently unclear if the leopard seal intended to kill the biologist, but is most importantly a sobering reminder of the true nature of these wild animals.
9. Leopard Seals Have a Very Diverse Diet
Antarctic krill compose about 45% of the leopard seal’s overall diet. Their teeth are grooved in specialized ways that allow them to filter krill out of the water, making them easy prey items to consume. Their diets can vary, however, depending on their location and availability of other tastier prey items. Unlike other members of the seal family, the leopard seal’s diet includes other Antarctic marine mammals. Most commonly, the crabeater seal, Weddell seal, and Antarctic fur seal fall prey to the leopard seal’s insatiable appetite. In addition to Antarctic mammals, leopard seals have an acquired a taste for Adèlie, Gentoo, Chinstrap, Rockhopper, King, and Emperor penguins, and have also been known to eat fish and cephalopods. There’s really nothing that they won’t eat!
10. They “Play” With Their Food
When a leopard seal grows tired of eating, but still wants to be entertained, they’ll seek out penguins or young seals to play “cat and mouse” with. As a penguin swims towards to shore, the seal will cut them off and chase them back towards the water. They’ll do this over and over again, until the penguin either successfully makes it back to shore, or succumb to exhaustion. There doesn’t seem to be any point to this game, especially since the seals are expending great amounts of energy on this game, and may not even eat the animals that they kill. Scientists have speculated that this is distinctly for sport, or could possibly be younger, immature seals looking to sharpen their hunting skills.
While cruising through Antarctic waters, make sure to always keep an eye out on ice floes for sleeping leopard seals. When they’re not searching for a meal or a game to play, they’ll haul out on the ice to rest. Their distinctive features and unmistakable grin make them an easy spot!