Antarctic sea lion Steller Sea lion are the largest of the eared seals, with males weighing as much as ton and females about 270 kilograms. Named after an explorer who explored the east coast of Russia, they live in the North Pacific and breed in Kamchatka, the Pribilof Islands, and North America as far south as southern California.
California sea lions are commonly used as trained sea seals in circus and ocean park shows. Adult males weigh up to 300 kilograms and develop a prominent forehead bulge. They breed across the California coast and in the Galapagos Islands.
The South American sea lion forms breeding colonies across southern South America from Peru to Uruguay. In Spanish they are know as Lobos marinos , or sea wolves.
Australian Sea lion is a nonmigratory pinniped. It spends it entire life around beaches where it is born and has become tolerant to seal-watching tourists. They were never very numerous. There are thought to be less than 6,000 of them today.
Hooker’s sea lion lives in island groups south of New Zealand. Also known as the New Zealand sea lion, it was nearly wiped in the 19th century but are now protected. Males are almost black. Females and young males are silvery gray.
fur seal Fur seals are sea lions not seals. They have forward-pointing back limbs, which allows them to get around on land, and have soft dense fur next to their skin. Coarse guard hairs provide a dense outer coat. Males remain in polar regions the year round but females migrate to warmer climates to give birth to their young. One of the main that distinguished sea lions and fur seals is that the latter has thick underfur.
Fur seals were once extensively hunted for their furs. The fur is waterproof and very warm for the seals on land and at in surface waters. Their fur loses it warmth when the animal dives because under great pressure the water squeezes out the relatively warm air between the hairs.
Southern fur include seven distinct species, of all of which live south of the Equator except the Guadalupe fur seal, The South African and Australian are the largest. The primary thing that different them is geography, although some breed on the beaches in the. same island groups of the southern oceans.
Northern Fur Seals
Northern fur seal bull Northern fur seals range over a large area from the Bering Sea in the east to the Japanese islands of Hokkaido and Honshu in the west. Also known as the Alaska or Proibilof fur seal, northern fur seals feed on fish and squid and hunt at night. They have very sensitive whiskers which they use to track prey They in turn are fed on by sharks and killer whales. Sometimes pups are taken by foxes on land. There are more than a million of them.
Northern fur seals get their name from their fur, which looks black when wet but is brownish gray or reddish brown on males and silvery-gray with a white patch on females. Adult males reach a length of 2.1 meters. Females reach 1.4 meters. Pups are 60 centimeters long when they are born.
Dominant males form harems with 20 or 30 members and occasionally up to 100. They copulate with females for a month without eating and lose about 25 percent of their body weight. Sometimes females mate again within 48 hours of giving birth.
Northern fur seals often sleep in the open sea. They sleep unihemispherically, which means that one hemisphere of the brain sleeps while the other is awake. Their hair is densely packed at 60,000 hairs per square centimeter, forming a waterproof coat and layer of insulation that allows the animal to thrive in cold water and deep sea environments. Their blood contains 3½ times the hemoglobin of humans.
Northern fur seals have been hunted by Russians, Americans, Canadians and Japanese. for their fur and body parts which are regarded as having medicinal properties. One Japanese shogun ate fur seal extracts for strength. Hunting them is a matter of considerable controversy. Images of baby fur seals being clubbed
Warm Sea Seals
Hawaiian monk seal The Mediterranean monk seal is severely endangered and among the rarest of pinnipeds. Less than 1,000 of them survive in small populations in the Canary Islands, Madeira Islands and Morocco and along the European and African coast. Adult may be 2.8 meters in length and weigh 300 kilograms.
The Caribbean monk seal is now extinct. First described by Columbus and last seen off of Jamaica in 1952, it inhabited the Antilles, the Bahamas and the Florida Keys.
The Hawaiian monk sea is found in the northwestern Hawaiian islands. It was hunted nearly to extinct in the 1800s. The remnant population remained virtually undisturbed until fighting broke out on Midway Island in World War II.
Weddell seal Wendell seals probably live further south than any other mammal. They spend a great deal of time under ice, breathing through holes they make with specially developed canine teeth, They can dive to a depth of around 600 meters and stay down for about an hour.The lungs of Wendell seals collapse at a depth of around 100 feet and stay collapsed when the seal dives further and reinflate when the animal ascends.
The Ross seal is a medium-size seal that rarely exceed 2.5 meters in length. It is a solitary animal and probably the least studied of all pinnipeds. When approached by humans it produces unusual clicking and gurgling noises.
The crabeater seal is found throughout the Antarctic. Despite its name its prime food source is krill, which it filters from the water like baleen whales. They are the most abundant seal in the world. Their population is thought to exceed 15 million.
Leopard seals are found throughout the Antarctic and nearby islands and have been seen as far north as Australia, South America and South Africa. The are notorious predators who feed on penguins, fish, squid, krill and other seals, mostly crabeater seal and fur seal pups. They are only known seals to regularly hunt warm-blooded prey. To that end they have sharp front canines and incisors designed for capturing and shredding prey and back molars with sharp edge for grasping and cutting, but also with interlocking cusps to sift krill. Their name comes from their patterned skin. [Source:Paul Nicklen, Kim. Heacox, National Geographic, November 2006]
Leopard seals reach a length of four meters and weigh half a ton. Females are larger than males in size. Both have extremely large heads which look too big for their slender bodies. Despite this they move with amazing speed and agility.
For many leopard seals, penguins are their primary prey. They often cruise along the edges of ice flows, looking for penguins they can take. A favorite target in the austral summer is newly fledged penguins going into the sea for the first time.
Leopard seals roam a huge area. Little is known about their biology and even their numbers. Estimates range from 200,000 to 400,000. Because they eat whatever is available scientists track their diets to get a sense of the available food supply in an area. By chemically analyzing their whiskers, scientists can determine roughly three years of feeding patterns.
Leopard Seal Attacks
leopard seal The crew of the famous Shackleton expedition in 1914 had several encounters with leopard seals. Thomas Orde-Lees was skiing across an ice flow when a leopard seal emerged between two ice flows and lunged after him. Orde-Lees managed to escape only to have the seal track him from below the ice and attack again from ahead. Orde-Lees shouted for help. Another member of the expedition, Frank Wild, shot the leopard seal dead.
Describing close encounters with a leopard seal Paul Nicklen wrote in National Geographic, “I expected this 12-foot-log female to flee with her catch, a live penguin chick, but instead she dropped it on my camera. Then she opened her mouth and engulfed the camera---and most of my head. After 45 minutes of more threats, she finally relaxed and ate.” On another encounter he wrote, “In a lethal game of cat and mouse, the large female...caught and released this penguin chick...for more than an hour, repeatedly presenting it to me. When I ignored her, she blew a stream of bubbles from her nose in a threat display and tried again...More frightening than the canines of the large female was the deep jackhammer sound she let loose that rattled through my chest.”
Goran Ehlme, a Swedish cinematographer who has spent years with leopard seals, said their reputation for fierceness is somewhat undeserved. Mostly they are just inquisitive he said. “It makes a better story to tell about a ferocious animal than it does tell about a curious one,” he said. “People tend to judge animals in frightening moments. But these seals, they are mostly curious.” Even so Antarctic research stations advice anyone not doing research to stay out of the water if they sea a leopard seal.
Leopard Seal Kills a Biologist
leopard seal In July 2003, Kirsty Brown, a 28-year-old marine biologist, was snorkeling off the Antarctic Peninsula, when she was grabbed, pulled down and drowned by the leopard seal, her colleagues worked for an hour to revive her, but could not. There had been reports of leopard seals harassing people and puncturing inflatable boats but his was the first report of a human fatality by a leopard seal.
According to Reuters Brown was attacked by a leopard seal while she carried out research close to the Rothera research station, about 800 miles south of the Falkland Islands. Horrified colleagues watched as Brown, a qualified diver, was pulled underwater and drowned by the seal.
Professor Chris Rapley, director of the British Antarctic Survey (BAS), said Brown's death had shocked her colleagues. "In 30 years we have never experienced anything like this," a BAS spokesman told the Daily Telegraph newspaper. "Leopard seals are incredibly inquisitive, but are not normally aggressive. If a diver can see a leopard seal, then they will not go in the water because there is a small risk. But to our knowledge, this has never happened before."
Leopard Seal and Penguins
Leopard seals are a penguin's greatest worry. As many as one in every three penguins may be taken these nine-foot-long predators. Peterson once came across a group of penguins who sought refuge on an ice flow, "Two of the birds were mutilated and bloody," he said. "The predatory seal, lurking under the lip of the ice, surfaced two or three times, watching us. Then an incautious penguin plunged in and swam for shore. Quick as a flash the leopard seal grabbed [the penguin] and thrashed it this way and that, literally shook the body out of the skin. A leopard seal will feed on krill, by when near a penguin colony it likes its krill pre-processed."
Penguins are known to leap into the boats of tourists when pursued by a leopard seal. On land or ice where the seal isn't so adept penguins will strut within a few feet of the predator.
Paul Nicklen witnessed leopard seals take several penguin chicks. He said what the seals prized most was a penguin stomach filled with krill and that it took them significantly more time to catch adult penguins than their young. On one attack he wrote in National Geographic, “In a death shake, the large female shred a penguin chick by whipping it from side to side...All I saw was a splash and storm petrels and gulls gathering for scraps...the large female dived to eat her prey.”
The gray seal is found in Canada and northwestern Europe, with the largest concentration in the British isles. It can reach a length of 2.3 meters and is sometimes called the “horsehead” seal because of its long snout.
harbor seal Harbor seals are found throughout the temperate, Arctic and subarctic coastal waters of the Northern Hemisphere. They primarily feed on fish and spend most of their time in the same area and are known for raiding fishermen’s nets.
Larga seals are found from northern Alaska to Korea. Also known as spotted seals or largha seals, they are similar to harbor seal but are smaller, reaching lengths of 1.7 meters. There are thought to be about 400,000 of them in the Bering and Okhotsk Seas. Larga seal pups are covered with cream-colored fur when they are born. The fur serves as camouflage the snow, protecting them from potential predators. Their adult spots begin developing about a month after birth, around the same time they stop being breast fed and enter a period of post-weaning fasting when their weight drops from around 40 kilograms to around 30 kilograms. During that time they get their nutrition from fat stored in their bodies.
Bearded seals are the largest northern seal. They can reach 2.5 meters in length and weigh 340 kilograms. Usually solitary they were hunted by the sealing industry. Inuit still hunt them for meat, leather and oil. A critter cam was hooked up to one in 1997 by National Geographic researchers.
Bearded seals give birth and rear pups on drifting pack ice over shallow waters where prey is abundant. They're very similar to walrus in behavior. They're bottom feeders. They eat crabs and shelled organisms on the floor, so they need ice over shallow water, over the (continental) shelf. If the ice retreats too far off the shelf, they're denied access to their food source." When females give birth, they need ice to last long enough in the spring and early summer to successfully reproduce and then molt, or shed and grown back their fur.
bearded seal Hooded seals can dive very deep and hunt fish in deep waters of the North Atlantic and Arctic. Males have highly elastic black bladders on their nose and on top of their head. Both are interconnected and used in breeding displays. Males also possess a red nasal bladder, the source of their nickname bladdernose.
Hooded seals inflate their nasal bladders like elephant seals. They can close both nostrils and exhale, inflating black skin bladder, or they can close one nostril and exhale, blowing out the blood red sack
On a hood seal male, BBC television naturalist David Attenborough wrote: “He lies lazily besides a female, he lazily blows air from one nostril to the other. If another male approaches, however, he inflates both at the same time so they come together and form a large black hood twice the size of a football. As the intruder gets closer, the resident shuts one nostril and blows down the other, inflating a nasal membrane into a gigantic scarlet balloon, he then shakes it violently from side to side so that it makes a pinging noise. This usually is enough to dissuade any intruder from persisting.”
Ribbon seal Ringed seals inhabit the circumpolar pack-ice waters north to North Pole. Adults average 1.25 meters in length. Pups are in sow caves or tunnels These seal are hunted by Inuit for fur, meat and blubber. Ringed seals can live in completely ice-covered waters, using stout claws to dig and maintain breathing holes. They excavate snow caves on sea ice to provide insulated shelters for themselves and their pups. Young ringed seal pups cannot survive in water. They are susceptible to temperature stresses until they grow a blubber layer and shed their lanugo, the white, wooly coat they're born with.
Ribbon seals are born white and attain their distinctive black and white ribbon patterns after several molts. They are particularly adept on ice. There are thought to be around 250,000 of them in the Bering and Okhotsk Seas.
Harp seals are named for the harp-shaped pattern on their backs. For a while they were assaulted are harvested in Greenland and Newfoundland. The Newfoundland hunt drew some notoriety for the clubbing of baby seals. The hunt was suspended.
Image Sources: Wikimedia Commons, National Oceanic and Atmospheric Administration (NOAA)
Text Sources: New York Times, Washington Post, Los Angeles Times, Times of London, Yomiuri Shimbun, The Guardian, National Geographic, The New Yorker, Time, Newsweek, Reuters, AP, Lonely Planet Guides, Compton’s Encyclopedia and various books and other publications.
© 2008 Jeffrey Hays
Last updated January 2012