Seals | Polar Unbound

Seals

Southern Elephant Seal

SOUTHERN ELEPHANT SEAL

The southern elephant seal is the largest seal in the world as well as
the largest extant carnivore, with males weighing on average 7,000 pounds. Females, on the other hand, are smaller, only weighing an average of 1,700. The largest bull ever recorded weighed 11,000 pounds and was nearly 23 feet long.

Elephant seal pups are born with thick, completely black coats that make it impossible for them to swim but protect them from the frigid temperatures. Their first molt corresponds with weaning and the ability to go swimming. Like all seals, the elephant seal’s cardiovascular system protects itself from the cold by enveloping the arteries with small veins, capturing the heat. This structure cardiovascular is especially important in the extremities.

Elephant pups can remain on land for quite a long time, sometimes as long as several weeks. Males will usually arrive first and fight for control and breeding rights over the forthcoming females. Though the most dominant males maintain control over the harems, this dominance does not ensure that only they will mate with the female cows. Many of the less successful males will attempt to mate when the dominant one is not looking or even out at sea, where they are much less likely to be spotted by the dominant male.

Males must remain in their territory to properly defend it and will often go months without eating to do so. Some males will stay ashore for up to three months without food, protecting their territory from other males. Posturing and vocalization with coughing roars often solve fights between two high-ranking males. When conflict does arise, males use their teeth and their against each other and their weight to gain advantage. Conflicts are rarely fatal. The defeated will flee the scene to heal their wounds.

Due to their massive size elephant seals have few predators. Those they do have usually prey upon them in the water, such as orcas and sharks. Occasionally leopard seals have been known to prey upon smaller, adolescent pups.

Leopard Seal

LEOPARD SEAL

The leopard seal is the second largest species of seal in Antarctica. While the southern elephant seals mostly live away from the Antarctica, only visiting for hunting, breeding, and resting, the leopard seal makes its home on the shores of the frozen desert Continent. They are much smaller than their elephant seal relatives, ranging from 440-1,300
pounds. 

For a number of reasons the leopard seal is much harder to survey than the southern elephant. In the first place, they are solitary animals. However, they also spend a significant portion of the spring and summer months, when scientific surveys most commonly occur, 
underwater. While underwater males will vocalize, which has allowed them to be surveyed acoustically. Underwater, the seal will hang upside down and sing with his back bent, rocking from side to side.  

Like birds, leopard seals have age-related differences in their calling patterns. Younger seals will have many different styles of calling; older seals have utilize only a few, highly stylized calls ranging from bird-like trills to low, piercing moans. Each male is capable of producing a distinctive song, believed to be linked to their breeding behavior.

In the water. leopard seals are bold, curious, and often playful. Their most common prey are fish, krill, and squid, but larger leopard seals will also eat penguins. Though they often prey upon penguins, leopard seals will sometimes play with a penguin it does not intend to eat. Though leopard seals have been known to attack divers, a leopard seal once famously developed a close relationship with a photographer for National Geographic, bringing him  penguins in an effort, it is thought, to teach the photographer how to hunt.

Weddell Seal

WEDDELL SEAL

Weddell seals belong to the group known as “true seals” along with the harp seals. They are circumpolar and tend to stick near the coast, where they enjoy inhabiting regions of fast ice with only short trips farther out into the ocean. Even when they haul out of the ice, they keep close to their access hole and breeding colonies. 

As Weddell seals live under the fast ice, they stick close to their breathing holes and cracks in order to breath. During the winter, when cracks in the ice are much less common, Weddell seals use their shark incisor and canine teeth to tear open new breathing holes. Though this is hard on their teeth and keeps them close to “home,” it also protects them from air-breathing predators such as orcas and leopard seals. 

 

Antarctic Fur seal

ANTARCTIC FUR SEALS 

Antarctic fur seals are the only eared seal that live in Antarctica, where they enjoy the nutrient-rich waters of the transition zone between the frigid Antarctic waters and the balmier northern waters. Though they can be found on several Antarctic islands including the South Shetlands, South Orkneys, South Sandwiches and Heard Island, about 95% of the entire population breeds on South Georgia island. When not breeding, Antarctic fur seals enjoy leading a largely oceangoing existence, traveling to where the krill is most abundant. 

Antarctic fur seals can be identified by their ears, dense dark fur, and the ability to move around on “all fours.” While males tend to be dark brown, females and younger fur seals tend to be grey with light underbellies. Pups are actually black before molting to a silver-grey coat. 

FUN FACT: Unlike other seals, Antarctic fur seals rely on their thick fur to keep warm rather than  insulating fat. 

 

Ross Seal

ROSS SEAL

Ross seals, named after the British explorer Sir James Clark Ross who led the Terror and Erebus expeditions to the Antarctic, are the least abundant of the Antarctic seals and possibly the most enigmatic. Little is known of their population distribution or behavioral patterns. Not only do they tend to be solitary creatures, but they keep to the thickest pack ice. If you do spot one, they can be identified by the unique streaked pattern that runs down their neck and throat—sometimes resembling a mask—rather than the mottled or spotted pattern decorating most other seals.  

Ross seals are circumpolar and the only Antarctic seals that don’t stray beyond the Antarctic seas. They are well adapted to the Antarctic environment with needle-like teeth which they use to catch slippery squid and fish as well as their large eyes that serve them well for hunting in the dimly-lit waters. 

 

Crabeater Seal

CRABEATER SEAL

Crabeater seals enjoy Antarctica’s pack-ice, where they spend their entire lives. Though they may not be one of Antarctica’s most iconic seals, they are the most abundant seal species throughout the southern ocean and most likely the most abundant large mammal in the world. Though they have high numbers, leopard seals are a significant predator to crabeater seals, especially the pups. Crabeaters tend to be scarred from unsuccessful leopard seal attacks. 

Crabeaters have long snouts resembling a dog’s that match their slender bodies and well-adapted teeth whose sieve-like structure allow them to strain out krill when they swallow seawater, similar to baleen whales. Scientists consider a crabeater’s teeth to be the most specialized of any carnivore. 

Crabeater seals prefer diving and feeding throughout the night before hauling themselves up on the pack ice to rest by midday. Though they enjoy diving into the water for a good meal, individual crabeater seals have been known to travel impressive distances around Antarctica and even make it pretty far inland. 

FUN FACT: Despite their seemingly literal name, crabeater seals don’t eat crabs. 

 

Hooker's sea lions

HOOKER’S SEA LIONS 

Hooker’s sea lions, or New Zealand sea lions, are rare amongst seal species and one of the most localized as they breed in New Zealand’s subantarctic region. Though females stick closer to their breeding grounds, males venture further and can be seen on Macquarie Island. 

Hooker’s sea lions were named after Sir Joseph Hooker, a botanist who went on a British expedition to the Antarctic. They can dive deeper and stay underneath the water longer than any other sea lion. That being said, Hooker’s sea lions generally stick relatively close to home as they prey upon squid, fish and octopus.